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Schleh MW, Ahn C, Ryan BJ, Chugh OK, Luker AT, Luker KE, Gillen JB, Ludzki AC, Van Pelt DW, Pitchford LM, Zhang T, Rode T, Howton SM, Burant CF, Horowitz JF. Both moderate- and high-intensity exercise training increase intramyocellular lipid droplet abundance and modify myocellular distribution in adults with obesity. Am J Physiol Endocrinol Metab 2023; 325:E466-E479. [PMID: 37729021 PMCID: PMC10864005 DOI: 10.1152/ajpendo.00093.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 09/12/2023] [Accepted: 09/12/2023] [Indexed: 09/22/2023]
Abstract
Exercise training modifies lipid metabolism in skeletal muscle, but the effect of exercise training on intramyocellular lipid droplet (LD) abundance, size, and intracellular distribution in adults with obesity remains elusive. This study compared high-intensity interval training (HIIT) with more conventional moderate-intensity continuous training (MICT) on intramyocellular lipid content, as well as LD characteristics (size and number) and abundance within the intramyofibrillar (IMF) and subsarcolemmal (SS) regions of type I and type II skeletal muscle fibers in adults with obesity. Thirty-six adults with obesity [body mass index (BMI) = 33 ± 3 kg/m2] completed 12 wk (4 days/wk) of either HIIT (10 × 1 min, 90% HRmax + 1-min active recovery; n = 19) or MICT (45-min steady-state exercise, 70% HRmax; n = 17), while on a weight-maintaining diet throughout training. Skeletal muscle biopsies were collected from the vastus lateralis before and after training, and intramyocellular lipid content and intracellular LD distribution were measured by immunofluorescence microscopy. Both MICT and HIIT increased total intramyocellular lipid content by more than 50% (P < 0.01), which was attributed to a greater LD number per µm2 in the IMF region of both type I and type II muscle fibers (P < 0.01). Our findings also suggest that LD lipophagy (autophagy-mediated LD degradation) may be transiently upregulated the day after the last exercise training session (P < 0.02 for both MICT and HIIT). In summary, exercise programs for adults with obesity involving either MICT or HIIT increased skeletal muscle LD abundance via a greater number of LDs in the IMF region of the myocyte, thereby providing more lipid in close proximity to the site of energy production during exercise.NEW & NOTEWORTHY In this study, 12 wk of either moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT) enhanced skeletal muscle lipid abundance by increasing lipid droplet number within the intramyofibrillar (IMF) region of muscle. Because the IMF associates with high energy production during muscle contraction, this adaptation may enhance lipid oxidation during exercise. Despite differences in training intensity and energy expenditure between MICT and HIIT, their effects on muscle lipid abundance and metabolism were remarkably similar.
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Affiliation(s)
- Michael W Schleh
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Cheehoon Ahn
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Benjamin J Ryan
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Olivia K Chugh
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Austin T Luker
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Kathryn E Luker
- Department of Radiology, Center for Molecular Imaging, University of Michigan, Ann Arbor, Michigan, United States
- Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, United States
| | - Jenna B Gillen
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Alison C Ludzki
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Douglas W Van Pelt
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Lisa M Pitchford
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Tao Zhang
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Thomas Rode
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Suzette M Howton
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Charles F Burant
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States
| | - Jeffrey F Horowitz
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
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Ghovanloo MR, Effraim PR, Yuan JH, Schulman BR, Jacobs DS, Dib-Hajj SD, Waxman SG. Nav1.7 P610T mutation in two siblings with persistent ocular pain after corneal axon transection: impaired slow inactivation and hyperexcitable trigeminal neurons. J Neurophysiol 2023; 129:609-618. [PMID: 36722722 PMCID: PMC9988530 DOI: 10.1152/jn.00457.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/27/2023] [Accepted: 01/28/2023] [Indexed: 02/02/2023] Open
Abstract
Despite extensive study, the mechanisms underlying pain after axonal injury remain incompletely understood. Pain after corneal refractive surgery provides a model, in humans, of the effect of injury to trigeminal afferent nerves. Axons of trigeminal ganglion neurons that innervate the cornea are transected by laser-assisted in situ keratomileusis (LASIK). Although most patients do not experience postoperative pain, a small subgroup develop persistent ocular pain. We previously carried out genomic analysis and determined that some patients with persistent pain after axotomy of corneal axons during refractive surgery carry mutations in genes that encode the electrogenisome of trigeminal ganglion neurons, the ensemble of ion channels and receptors that regulate excitability within these cells, including SCN9A, which encodes sodium channel Nav1.7, a threshold channel abundantly expressed in sensory neurons that has been implicated in a number of pain-related disorders. Here, we describe the biophysical and electrophysiological profiling of the P610T Nav1.7 mutation found in two male siblings with persistent ocular pain after refractive surgery. Our results indicate that this mutation impairs the slow inactivation of Nav1.7. As expected from this proexcitatory change in channel function, we also demonstrate that this mutation produces increased spontaneous activity in trigeminal ganglion neurons. These findings suggest that this gain-of-function mutation in Nav1.7 may contribute to pain after injury to the axons of trigeminal ganglion neurons.NEW & NOTEWORTHY Mechanisms underlying pain after axonal injury remain elusive. A small subgroup of patients experience pain after corneal refractive surgery, providing a human pain model after well-defined injury to axons. Here we analyze a mutation (P610T) in Nav1.7, a threshold sodium channel expressed in nociceptors, found in two siblings with persistent ocular pain after refractive surgery. We show that it impairs channel slow inactivation, thereby triggering inappropriate repetitive activity in trigeminal ganglion axons that signal eye pain.
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Affiliation(s)
- Mohammad-Reza Ghovanloo
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States
- Center for Neuroscience and Regeneration Research, Yale University, West Haven, Connecticut, United States
- Neuro-Rehabilitation Research Center, Department of Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States
| | - Philip R Effraim
- Center for Neuroscience and Regeneration Research, Yale University, West Haven, Connecticut, United States
- Neuro-Rehabilitation Research Center, Department of Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States
- Department of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Jun-Hui Yuan
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States
- Center for Neuroscience and Regeneration Research, Yale University, West Haven, Connecticut, United States
- Neuro-Rehabilitation Research Center, Department of Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States
| | - Betsy R Schulman
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States
- Center for Neuroscience and Regeneration Research, Yale University, West Haven, Connecticut, United States
- Neuro-Rehabilitation Research Center, Department of Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States
| | - Deborah S Jacobs
- Cornea and Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States
| | - Sulayman D Dib-Hajj
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States
- Center for Neuroscience and Regeneration Research, Yale University, West Haven, Connecticut, United States
- Neuro-Rehabilitation Research Center, Department of Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States
- Center for Neuroscience and Regeneration Research, Yale University, West Haven, Connecticut, United States
- Neuro-Rehabilitation Research Center, Department of Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States
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3
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Postić S, Sarikas S, Pfabe J, Pohorec V, Križančić Bombek L, Sluga N, Skelin Klemen M, Dolenšek J, Korošak D, Stožer A, Evans-Molina C, Johnson JD, Slak Rupnik M. High-resolution analysis of the cytosolic Ca 2+ events in β cell collectives in situ. Am J Physiol Endocrinol Metab 2023; 324:E42-E55. [PMID: 36449570 PMCID: PMC9829482 DOI: 10.1152/ajpendo.00165.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 11/15/2022] [Accepted: 11/22/2022] [Indexed: 12/02/2022]
Abstract
The release of peptide hormones is predominantly regulated by a transient increase in cytosolic Ca2+ concentration ([Ca2+]c). To trigger exocytosis, Ca2+ ions enter the cytosol from intracellular Ca2+ stores or from the extracellular space. The molecular events of late stages of exocytosis, and their dependence on [Ca2+]c, were extensively described in isolated single cells from various endocrine glands. Notably, less work has been done on endocrine cells in situ to address the heterogeneity of [Ca2+]c events contributing to a collective functional response of a gland. For this, β cell collectives in a pancreatic islet are particularly well suited as they are the smallest, experimentally manageable functional unit, where [Ca2+]c dynamics can be simultaneously assessed on both cellular and collective level. Here, we measured [Ca2+]c transients across all relevant timescales, from a subsecond to a minute time range, using high-resolution imaging with a low-affinity Ca2+ sensor. We quantified the recordings with a novel computational framework for automatic image segmentation and [Ca2+]c event identification. Our results demonstrate that under physiological conditions the duration of [Ca2+]c events is variable, and segregated into three reproducible modes, subsecond, second, and tens of seconds time range, and are a result of a progressive temporal summation of the shortest events. Using pharmacological tools we show that activation of intracellular Ca2+ receptors is both sufficient and necessary for glucose-dependent [Ca2+]c oscillations in β cell collectives, and that a subset of [Ca2+]c events could be triggered even in the absence of Ca2+ influx across the plasma membrane. In aggregate, our experimental and analytical platform was able to readily address the involvement of intracellular Ca2+ receptors in shaping the heterogeneity of [Ca2+]c responses in collectives of endocrine cells in situ.NEW & NOTEWORTHY Physiological glucose or ryanodine stimulation of β cell collectives generates a large number of [Ca2+]c events, which can be rapidly assessed with our newly developed automatic image segmentation and [Ca2+]c event identification pipeline. The event durations segregate into three reproducible modes produced by a progressive temporal summation. Using pharmacological tools, we show that activation of ryanodine intracellular Ca2+ receptors is both sufficient and necessary for glucose-dependent [Ca2+]c oscillations in β cell collectives.
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Affiliation(s)
- Sandra Postić
- Center for physiology and pharmacology, Medical University of Vienna, Vienna, Austria
| | - Srdjan Sarikas
- Center for physiology and pharmacology, Medical University of Vienna, Vienna, Austria
| | - Johannes Pfabe
- Center for physiology and pharmacology, Medical University of Vienna, Vienna, Austria
| | - Viljem Pohorec
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | | | - Nastja Sluga
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Dean Korošak
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Civil Engineering, Transportation Engineering and Architecture, University of Maribor, Maribor, Slovenia
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Carmella Evans-Molina
- Center for Diabetes and Metabolic Diseases and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana
- Richard L. Roudebush VA Medical Center, Indianapolis, Indiana
| | - James D Johnson
- Diabetes Research Group, Life Sciences Institute, Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marjan Slak Rupnik
- Center for physiology and pharmacology, Medical University of Vienna, Vienna, Austria
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Alma Mater Europaea-European Center Maribor, Maribor, Slovenia
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4
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Stanton-Turcotte D, Hsu K, Moore SA, Yamada M, Fawcett JP, Iulianella A. Mllt11 Regulates Migration and Neurite Outgrowth of Cortical Projection Neurons during Development. J Neurosci 2022; 42:3931-3948. [PMID: 35379703 PMCID: PMC9097781 DOI: 10.1523/jneurosci.0124-22.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/13/2022] [Accepted: 03/30/2022] [Indexed: 11/22/2022] Open
Abstract
The formation of connections within the mammalian neocortex is highly regulated by both extracellular guidance mechanisms and intrinsic gene expression programs. There are two types of cortical projection neurons (CPNs): those that project locally and interhemispherically and those that project to subcerebral structures such as the thalamus, hindbrain, and spinal cord. The regulation of cortical projection morphologies is not yet fully understood at the molecular level. Here, we report a role for Mllt11 (Myeloid/lymphoid or mixed-lineage leukemia; translocated to chromosome 11/All1 Fused Gene From Chromosome 1q) in the migration and neurite outgrowth of callosal projection neurons during mouse brain formation. We show that Mllt11 expression is exclusive to developing neurons and is enriched in the developing cortical plate (CP) during the formation of the superficial cortical layers. In cultured primary cortical neurons, Mllt11 is detected in varicosities and growth cones as well as the soma. Using conditional loss-of-function and gain-of-function analysis we show that Mllt11 is required for neuritogenesis and proper migration of upper layer CPNs. Loss of Mllt11 in the superficial cortex of male and female neonates leads to a severe reduction in fibers crossing the corpus callosum (CC), a progressive loss in the maintenance of upper layer projection neuron gene expression, and reduced complexity of dendritic arborization. Proteomic analysis revealed that Mllt11 associates with stabilized microtubules, and Mllt11 loss affected microtubule staining in callosal axons. Taken together, our findings support a role for Mllt11 in promoting the formation of mature upper-layer neuron morphologies and connectivity in the cerebral cortex.SIGNIFICANCE STATEMENT The regulation of cortical projection neuron (CPN) morphologies is an area of active investigation since the time of Cajal. Yet the molecular mechanisms of how the complex dendritic and axonal morphologies of projection neurons are formed remains incompletely understood. Although conditional mutagenesis analysis in the mouse, coupled with overexpression assays in the developing fetal brain, we show that a novel protein called Mllt11 is sufficient and necessary to regulate the dendritic and axonal characteristics of callosal projection neurons in the developing mammalian neocortex. Furthermore, we show that Mllt11 interacts with microtubules, likely accounting for its role in neuritogenesis.
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Affiliation(s)
- Danielle Stanton-Turcotte
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - Karolynn Hsu
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - Samantha A Moore
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - Makiko Yamada
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - James P Fawcett
- Departments of Phamacology, Surgery, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - Angelo Iulianella
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
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5
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Hoyeck MP, Matteo G, MacFarlane EM, Perera I, Bruin JE. Persistent organic pollutants and β-cell toxicity: a comprehensive review. Am J Physiol Endocrinol Metab 2022; 322:E383-E413. [PMID: 35156417 PMCID: PMC9394781 DOI: 10.1152/ajpendo.00358.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 12/20/2021] [Accepted: 02/07/2022] [Indexed: 01/09/2023]
Abstract
Persistent organic pollutants (POPs) are a diverse family of contaminants that show widespread global dispersion and bioaccumulation. Humans are continuously exposed to POPs through diet, air particles, and household and commercial products; POPs are consistently detected in human tissues, including the pancreas. Epidemiological studies show a modest but consistent correlation between exposure to POPs and increased diabetes risk. The goal of this review is to provide an overview of epidemiological evidence and an in-depth evaluation of the in vivo and in vitro evidence that POPs cause β-cell toxicity. We review evidence for six classes of POPs: dioxins, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), flame retardants, and per- and polyfluoroalkyl substances (PFAS). The available data provide convincing evidence implicating POPs as a contributing factor driving impaired glucose homeostasis, β-cell dysfunction, and altered metabolic and oxidative stress pathways in islets. These findings support epidemiological data showing that POPs increase diabetes risk and emphasize the need to consider the endocrine pancreas in toxicity assessments. Our review also highlights significant gaps in the literature assessing islet-specific endpoints after both in vivo and in vitro POP exposure. In addition, most rodent studies do not consider the impact of biological sex or secondary metabolic stressors in mediating the effects of POPs on glucose homeostasis and β-cell function. We discuss key gaps and limitations that should be assessed in future studies.
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Affiliation(s)
- Myriam P Hoyeck
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Geronimo Matteo
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Erin M MacFarlane
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Ineli Perera
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Jennifer E Bruin
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
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6
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Medlock L, Sekiguchi K, Hong S, Dura-Bernal S, Lytton WW, Prescott SA. Multiscale Computer Model of the Spinal Dorsal Horn Reveals Changes in Network Processing Associated with Chronic Pain. J Neurosci 2022; 42:3133-3149. [PMID: 35232767 PMCID: PMC8996343 DOI: 10.1523/jneurosci.1199-21.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 02/17/2022] [Accepted: 02/17/2022] [Indexed: 11/21/2022] Open
Abstract
Pain-related sensory input is processed in the spinal dorsal horn (SDH) before being relayed to the brain. That processing profoundly influences whether stimuli are correctly or incorrectly perceived as painful. Significant advances have been made in identifying the types of excitatory and inhibitory neurons that comprise the SDH, and there is some information about how neuron types are connected, but it remains unclear how the overall circuit processes sensory input or how that processing is disrupted under chronic pain conditions. To explore SDH function, we developed a computational model of the circuit that is tightly constrained by experimental data. Our model comprises conductance-based neuron models that reproduce the characteristic firing patterns of spinal neurons. Excitatory and inhibitory neuron populations, defined by their expression of genetic markers, spiking pattern, or morphology, were synaptically connected according to available qualitative data. Using a genetic algorithm, synaptic weights were tuned to reproduce projection neuron firing rates (model output) based on primary afferent firing rates (model input) across a range of mechanical stimulus intensities. Disparate synaptic weight combinations could produce equivalent circuit function, revealing degeneracy that may underlie heterogeneous responses of different circuits to perturbations or pathologic insults. To validate our model, we verified that it responded to the reduction of inhibition (i.e., disinhibition) and ablation of specific neuron types in a manner consistent with experiments. Thus validated, our model offers a valuable resource for interpreting experimental results and testing hypotheses in silico to plan experiments for examining normal and pathologic SDH circuit function.SIGNIFICANCE STATEMENT We developed a multiscale computer model of the posterior part of spinal cord gray matter (spinal dorsal horn), which is involved in perceiving touch and pain. The model reproduces several experimental observations and makes predictions about how specific types of spinal neurons and synapses influence projection neurons that send information to the brain. Misfiring of these projection neurons can produce anomalous sensations associated with chronic pain. Our computer model will not only assist in planning future experiments, but will also be useful for developing new pharmacotherapy for chronic pain disorders, connecting the effect of drugs acting at the molecular scale with emergent properties of neurons and circuits that shape the pain experience.
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Affiliation(s)
- Laura Medlock
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Kazutaka Sekiguchi
- Drug Developmental Research Laboratory, Shionogi Pharmaceutical Research Center, Toyonaka, Osaka 561-0825, Japan
- State University of New York Downstate Health Science University, Brooklyn, New York 11203
| | - Sungho Hong
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan
| | - Salvador Dura-Bernal
- State University of New York Downstate Health Science University, Brooklyn, New York 11203
- Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962
| | - William W Lytton
- State University of New York Downstate Health Science University, Brooklyn, New York 11203
- Kings County Hospital, Brooklyn, New York 11207
| | - Steven A Prescott
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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7
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Popp NJ, Hernandez-Castillo CR, Gribble PL, Diedrichsen J. The role of feedback in the production of skilled finger sequences. J Neurophysiol 2022; 127:829-839. [PMID: 35235441 PMCID: PMC8957329 DOI: 10.1152/jn.00319.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 02/28/2022] [Accepted: 03/01/2022] [Indexed: 11/22/2022] Open
Abstract
Actions involving fine control of the hand, for example, grasping an object, rely heavily on sensory information from the fingertips. Although the integration of feedback during the execution of individual movements is well understood, less is known about the use of sensory feedback in the control of skilled movement sequences. To address this gap, we trained participants to produce sequences of finger movements on a keyboard-like device over a 4-day training period. Participants received haptic, visual, and auditory feedback indicating the occurrence of each finger press. We then either transiently delayed or advanced the feedback for a single press by a small amount of time (30 or 60 ms). We observed that participants rapidly adjusted their ongoing finger press by either accelerating or prolonging the ongoing press, in accordance with the direction of the perturbation. Furthermore, we could show that this rapid behavioral modulation was driven by haptic feedback. Although these feedback-driven adjustments reduced in size with practice, they were still clearly present at the end of training. In contrast to the directionally specific effect we observed on the perturbed press, a feedback perturbation resulted in a delayed onset of the subsequent presses irrespective of perturbation direction or feedback modality. This observation is consistent with a hierarchical organization of even very skilled and fast movement sequences, with different levels reacting distinctly to sensory perturbations.NEW & NOTEWORTHY Sensory feedback is important during the execution of a movement. However, little is known about how sensory feedback is used during the production of movement sequences. Here, we show two distinct feedback processes in the execution of fast finger movement sequences. By transiently delaying or advancing the feedback of a single press within a sequence, we observed a directionally specific effect on the perturbed press and a directionally non-specific effect on the subsequent presses.
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Affiliation(s)
- Nicola J Popp
- The Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
| | | | - Paul L Gribble
- The Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
- Department of Psychology, University of Western Ontario, London, Ontario, Canada
- Department of Physiology & Pharmacology, University of Western Ontario, London, Ontario, Canada
- Haskins Laboratories, New Haven, Connecticut
| | - Jörn Diedrichsen
- The Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
- Department of Statistical and Actuarial Sciences, University of Western Ontario, London, Ontario, Canada
- Department of Computer Science, University of Western Ontario, London, Ontario, Canada
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8
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Tracy EP, Stielberg V, Rowe G, Benson D, Nunes SS, Hoying JB, Murfee WL, LeBlanc AJ. State of the field: cellular and exosomal therapeutic approaches in vascular regeneration. Am J Physiol Heart Circ Physiol 2022; 322:H647-H680. [PMID: 35179976 PMCID: PMC8957327 DOI: 10.1152/ajpheart.00674.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 01/19/2023]
Abstract
Pathologies of the vasculature including the microvasculature are often complex in nature, leading to loss of physiological homeostatic regulation of patency and adequate perfusion to match tissue metabolic demands. Microvascular dysfunction is a key underlying element in the majority of pathologies of failing organs and tissues. Contributing pathological factors to this dysfunction include oxidative stress, mitochondrial dysfunction, endoplasmic reticular (ER) stress, endothelial dysfunction, loss of angiogenic potential and vascular density, and greater senescence and apoptosis. In many clinical settings, current pharmacologic strategies use a single or narrow targeted approach to address symptoms of pathology rather than a comprehensive and multifaceted approach to address their root cause. To address this, efforts have been heavily focused on cellular therapies and cell-free therapies (e.g., exosomes) that can tackle the multifaceted etiology of vascular and microvascular dysfunction. In this review, we discuss 1) the state of the field in terms of common therapeutic cell population isolation techniques, their unique characteristics, and their advantages and disadvantages, 2) common molecular mechanisms of cell therapies to restore vascularization and/or vascular function, 3) arguments for and against allogeneic versus autologous applications of cell therapies, 4) emerging strategies to optimize and enhance cell therapies through priming and preconditioning, and, finally, 5) emerging strategies to bolster therapeutic effect. Relevant and recent clinical and animal studies using cellular therapies to restore vascular function or pathologic tissue health by way of improved vascularization are highlighted throughout these sections.
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Affiliation(s)
- Evan Paul Tracy
- Cardiovascular Innovation Institute and the Department of Physiology, University of Louisville, Louisville, Kentucky
| | - Virginia Stielberg
- Cardiovascular Innovation Institute and the Department of Physiology, University of Louisville, Louisville, Kentucky
| | - Gabrielle Rowe
- Cardiovascular Innovation Institute and the Department of Physiology, University of Louisville, Louisville, Kentucky
| | - Daniel Benson
- Cardiovascular Innovation Institute and the Department of Physiology, University of Louisville, Louisville, Kentucky
- Department of Bioengineering, University of Louisville, Louisville, Kentucky
| | - Sara S Nunes
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Heart & Stroke/Richard Lewar Centre of Excellence, University of Toronto, Toronto, Ontario, Canada
| | - James B Hoying
- Advanced Solutions Life Sciences, Manchester, New Hampshire
| | - Walter Lee Murfee
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
| | - Amanda Jo LeBlanc
- Cardiovascular Innovation Institute and the Department of Physiology, University of Louisville, Louisville, Kentucky
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9
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Grondin JM, Déjean G, Van Petegem F, Brumer H. Cell Surface Xyloglucan Recognition and Hydrolysis by the Human Gut Commensal Bacteroides uniformis. Appl Environ Microbiol 2022; 88:e0156621. [PMID: 34731054 PMCID: PMC8752140 DOI: 10.1128/aem.01566-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/24/2021] [Indexed: 11/20/2022] Open
Abstract
Xyloglucan (XyG) is a ubiquitous plant cell wall hemicellulose that is targeted by a range of syntenic, microheterogeneous xyloglucan utilization loci (XyGUL) in Bacteroidetes species of the human gut microbiota (HGM), including Bacteroides ovatus and B. uniformis. Comprehensive biochemical and biophysical analyses have identified key differences in the protein complements of each locus that confer differential access to structurally diverse XyG side chain variants. A second, nonsyntenic XyGUL was previously identified in B. uniformis, although its function in XyG utilization compared to its syntenic counterpart was unclear. Here, complementary enzymatic product profiles and bacterial growth curves showcase the notable preference of BuXyGUL2 surface glycan-binding proteins (SGBPs) to bind full-length XyG, as well as a range of oligosaccharides produced by the glycoside hydrolase family 5 (GH5_4) endo-xyloglucanase from this locus. We use isothermal titration calorimetry (ITC) to characterize this binding capacity and pinpoint the specific contributions of each protein to nutrient capture. The high-resolution structure of BuXyGUL2 SGBP-B reveals remarkable putative binding site conservation with the canonical XyG-binding BoXyGUL SGBP-B, supporting similar roles for these proteins in glycan capture. Together, these data underpin the central role of complementary XyGUL function in B. uniformis and broaden our systems-based and mechanistic understanding of XyG utilization in the HGM. IMPORTANCE The omnipresence of xyloglucans in the human diet has led to the evolution of heterogeneous gene clusters in several Bacteroidetes species in the HGM, each specially tuned to respond to the structural variations of these complex plant cell wall polysaccharides. Our research illuminates the complementary roles of syntenic and nonsyntenic XyGUL in B. uniformis in conferring growth on a variety of XyG-derived substrates, providing evidence of glycan-binding protein microadaptation within a single species. These data serve as a comprehensive overview of the binding capacities of the SGBPs from a nonsyntenic B. uniformis XyGUL and will inform future studies on the roles of complementary loci in glycan targeting by key HGM species.
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Affiliation(s)
- Julie M. Grondin
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Guillaume Déjean
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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10
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Taguer M, Darbinian E, Wark K, Ter-Cheam A, Stephens DA, Maurice CF. Changes in Gut Bacterial Translation Occur before Symptom Onset and Dysbiosis in Dextran Sodium Sulfate-Induced Murine Colitis. mSystems 2021; 6:e0050721. [PMID: 34874778 PMCID: PMC8651081 DOI: 10.1128/msystems.00507-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 10/20/2021] [Indexed: 11/30/2022] Open
Abstract
Longitudinal studies on the gut microbiome that follow the effect of a perturbation are critical in understanding the microbiome's response and succession to disease. Here, we use a dextran sodium sulfate (DSS) mouse model of colitis as a tractable perturbation to study how gut bacteria change their physiology over the course of a perturbation. Using single-cell methods such as flow cytometry, bioorthogonal noncanonical amino acid tagging (BONCAT), and population-based cell sorting combined with 16S rRNA sequencing, we determine the diversity of physiologically distinct fractions of the gut microbiota and how they respond to a controlled perturbation. The physiological markers of bacterial activity studied here include relative nucleic acid content, membrane damage, and protein production. There is a distinct and reproducible succession in bacterial physiology, with an increase in bacteria with membrane damage and diversity changes in the translationally active fraction, both, critically, occurring before symptom onset. Large increases in the relative abundance of Akkermansia were seen in all physiological fractions, most notably in the translationally active bacteria. Performing these analyses within a detailed, longitudinal framework determines which bacteria change their physiology early on, focusing therapeutic efforts in the future to predict or even mitigate relapse in diseases like inflammatory bowel diseases. IMPORTANCE Most studies on the gut microbiome focus on the composition of this community and how it changes in disease. However, how the community transitions from a healthy state to one associated with disease is currently unknown. Additionally, common diversity metrics do not provide functional information on bacterial activity. We begin to address these two unknowns by following bacterial activity over the course of disease progression, using a tractable mouse model of colitis. We find reproducible changes in gut bacterial physiology that occur before symptom onset, with increases in the proportion of bacteria with membrane damage, and changes in community composition of the translationally active bacteria. Our data provide a framework to identify possible windows of intervention and which bacteria to target in microbiome-based therapeutics.
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Affiliation(s)
- M. Taguer
- Department of Microbiology & Immunology, Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec, Canada
| | - E. Darbinian
- Department of Microbiology & Immunology, Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec, Canada
| | - K. Wark
- Department of Microbiology & Immunology, Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec, Canada
| | - A. Ter-Cheam
- Department of Mathematics and Statistics, Faculty of Science, McGill University, Montreal, Quebec, Canada
| | - D. A. Stephens
- Department of Mathematics and Statistics, Faculty of Science, McGill University, Montreal, Quebec, Canada
| | - C. F. Maurice
- Department of Microbiology & Immunology, Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec, Canada
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11
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Lindsey ML, Brunt KR, Kirk JA, Kleinbongard P, Calvert JW, de Castro Brás LE, DeLeon-Pennell KY, Del Re DP, Frangogiannis NG, Frantz S, Gumina RJ, Halade GV, Jones SP, Ritchie RH, Spinale FG, Thorp EB, Ripplinger CM, Kassiri Z. Guidelines for in vivo mouse models of myocardial infarction. Am J Physiol Heart Circ Physiol 2021; 321:H1056-H1073. [PMID: 34623181 PMCID: PMC8834230 DOI: 10.1152/ajpheart.00459.2021] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/05/2021] [Accepted: 10/05/2021] [Indexed: 12/11/2022]
Abstract
Despite significant improvements in reperfusion strategies, acute coronary syndromes all too often culminate in a myocardial infarction (MI). The consequent MI can, in turn, lead to remodeling of the left ventricle (LV), the development of LV dysfunction, and ultimately progression to heart failure (HF). Accordingly, an improved understanding of the underlying mechanisms of MI remodeling and progression to HF is necessary. One common approach to examine MI pathology is with murine models that recapitulate components of the clinical context of acute coronary syndrome and subsequent MI. We evaluated the different approaches used to produce MI in mouse models and identified opportunities to consolidate methods, recognizing that reperfused and nonreperfused MI yield different responses. The overall goal in compiling this consensus statement is to unify best practices regarding mouse MI models to improve interpretation and allow comparative examination across studies and laboratories. These guidelines will help to establish rigor and reproducibility and provide increased potential for clinical translation.
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Affiliation(s)
- Merry L Lindsey
- Department of Cellular and Integrative Physiology, Center for Heart and Vascular Research, University of Nebraska Medical Center, Omaha, Nebraska
- Research Service, Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - Keith R Brunt
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Saint John, New Brunswick, Canada
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago Stritch School of Medicine, Chicago, Illinois
| | - Petra Kleinbongard
- Institute for Pathophysiology, West German Heart and Vascular Center, University of Essen Medical School, Essen, Germany
| | - John W Calvert
- Carlyle Fraser Heart Center of Emory University Hospital Midtown, Atlanta, Georgia
- Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine, Atlanta, Georgia
| | - Lisandra E de Castro Brás
- Department of Physiology, The Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Kristine Y DeLeon-Pennell
- Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
- Research Service, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina
| | - Dominic P Del Re
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Nikolaos G Frangogiannis
- Division of Cardiology, Department of Medicine, The Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, New York
| | - Stefan Frantz
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Richard J Gumina
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, Ohio
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Ganesh V Halade
- Division of Cardiovascular Sciences, Department of Medicine, University of South Florida, Tampa, Florida
| | - Steven P Jones
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky
| | - Rebecca H Ritchie
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), Victoria, Australia
| | - Francis G Spinale
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the Columbia Veteran Affairs Medical Center, Columbia, South Carolina
| | - Edward B Thorp
- Department of Pathology and Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Crystal M Ripplinger
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
| | - Zamaneh Kassiri
- Department of Physiology, Cardiovascular Research Center, University of Alberta, Edmonton, Alberta, Canada
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12
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Tietjen I, Cassel J, Register ET, Zhou XY, Messick TE, Keeney F, Lu LD, Beattie KD, Rali T, Tebas P, Ertl HCJ, Salvino JM, Davis RA, Montaner LJ. The Natural Stilbenoid (-)-Hopeaphenol Inhibits Cellular Entry of SARS-CoV-2 USA-WA1/2020, B.1.1.7, and B.1.351 Variants. Antimicrob Agents Chemother 2021; 65:e0077221. [PMID: 34543092 PMCID: PMC8597786 DOI: 10.1128/aac.00772-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 09/10/2021] [Indexed: 12/16/2022] Open
Abstract
Antivirals are urgently needed to combat the global SARS-CoV-2/COVID-19 pandemic, supplement existing vaccine efforts, and target emerging SARS-CoV-2 variants of concern. Small molecules that interfere with binding of the viral spike receptor binding domain (RBD) to the host angiotensin-converting enzyme II (ACE2) receptor may be effective inhibitors of SARS-CoV-2 cell entry. Here, we screened 512 pure compounds derived from natural products using a high-throughput RBD/ACE2 binding assay and identified (-)-hopeaphenol, a resveratrol tetramer, in addition to vatalbinoside A and vaticanol B, as potent and selective inhibitors of RBD/ACE2 binding and viral entry. For example, (-)-hopeaphenol disrupted RBD/ACE2 binding with a 50% inhibitory concentration (IC50) of 0.11 μM, in contrast to an IC50 of 28.3 μM against the unrelated host ligand/receptor binding pair PD-1/PD-L1 (selectivity index, 257.3). When assessed against the USA-WA1/2020 variant, (-)-hopeaphenol also inhibited entry of a VSVΔG-GFP reporter pseudovirus expressing SARS-CoV-2 spike into ACE2-expressing Vero-E6 cells and in vitro replication of infectious virus in cytopathic effect and yield reduction assays (50% effective concentrations [EC50s], 10.2 to 23.4 μM) without cytotoxicity and approaching the activities of the control antiviral remdesivir (EC50s, 1.0 to 7.3 μM). Notably, (-)-hopeaphenol also inhibited two emerging variants of concern, B.1.1.7/Alpha and B.1.351/Beta in both viral and spike-containing pseudovirus assays with similar or improved activities over the USA-WA1/2020 variant. These results identify (-)-hopeaphenol and related stilbenoid analogues as potent and selective inhibitors of viral entry across multiple SARS-CoV-2 variants of concern.
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Affiliation(s)
- Ian Tietjen
- The Wistar Institute, Philadelphia, Pennsylvania, USA
| | - Joel Cassel
- The Wistar Institute, Philadelphia, Pennsylvania, USA
| | | | | | | | | | - Lily D. Lu
- The Wistar Institute, Philadelphia, Pennsylvania, USA
| | - Karren D. Beattie
- Griffith Institute for Drug Discovery, School of Environment and Science, Griffith University, Brisbane, QLD, Australia
| | - Topul Rali
- School of Natural and Physical Sciences, The University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - Pablo Tebas
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | | | - Rohan A. Davis
- Griffith Institute for Drug Discovery, School of Environment and Science, Griffith University, Brisbane, QLD, Australia
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13
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Botterill JJ, Khlaifia A, Walters BJ, Brimble MA, Scharfman HE, Arruda-Carvalho M. Off-Target Expression of Cre-Dependent Adeno-Associated Viruses in Wild-Type C57BL/6J Mice. eNeuro 2021; 8:ENEURO.0363-21.2021. [PMID: 34785571 PMCID: PMC8614227 DOI: 10.1523/eneuro.0363-21.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 11/21/2022] Open
Abstract
Adeno-associated viruses (AAVs) are a commonly used tool in neuroscience to efficiently label, trace, and/or manipulate neuronal populations. Highly specific targeting can be achieved through recombinase-dependent AAVs in combination with transgenic rodent lines that express Cre-recombinase in specific cell types. Visualization of viral expression is typically achieved through fluorescent reporter proteins (e.g., GFP or mCherry) packaged within the AAV genome. Although nonamplified fluorescence is usually sufficient to observe viral expression, immunohistochemical amplification of the fluorescent reporter is routinely used to improve viral visualization. In the present study, Cre-dependent AAVs were injected into the neocortex of wild-type C57BL/6J mice. While we observed weak but consistent nonamplified off-target double inverted open reading frame (DIO) expression in C57BL/6J mice, antibody amplification of the GFP or mCherry reporter revealed notable Cre-independent viral expression. Off-target expression of DIO constructs in wild-type C57BL/6J mice occurred independent of vendor, AAV serotype, or promoter. We also evaluated whether Cre-independent expression had functional effects via designer receptors exclusively activated by designer drugs (DREADDs). The DREADD agonist C21 (compound 21) had no effect on contextual fear conditioning or c-Fos expression in DIO-hM3Dq-mCherry+ cells of C57BL/6J mice. Together, our results indicate that DIO constructs have off-target expression in wild-type subjects. Our findings are particularly important for the design of experiments featuring sensitive systems and/or quantitative measurements that could be negatively impacted by off-target expression.
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Affiliation(s)
- Justin J Botterill
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - Abdessattar Khlaifia
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - Brandon J Walters
- Department of Cell & Systems Biology, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Mark A Brimble
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, Tennnessee 38105
| | - Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962
- Departments of Child & Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, and New York University Neuroscience Institute, New York University Langone Health, New York, New York 10016
| | - Maithe Arruda-Carvalho
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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14
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Mikolajczak A, Sallam NA, Singh RD, Scheidl TB, Walsh EJ, Larion S, Huang C, Thompson JA. Accelerated developmental adipogenesis programs adipose tissue dysfunction and cardiometabolic risk in offspring born to dams with metabolic dysfunction. Am J Physiol Endocrinol Metab 2021; 321:E581-E591. [PMID: 34459218 PMCID: PMC8791794 DOI: 10.1152/ajpendo.00229.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
This study determined if a perturbation in in utero adipogenesis leading to later life adipose tissue (AT) dysfunction underlies programming of cardiometabolic risk in offspring born to dams with metabolic dysfunction. Female mice heterozygous for the leptin receptor deficiency (Hetdb) had 2.4-fold higher prepregnancy fat mass and in late gestation had higher plasma insulin and triglycerides compared with wild-type (Wt) females (P < 0.05). To isolate the role of the intrauterine milieu, wild-type (Wt) offspring from each pregnancy were studied. Differentiation potential in isolated progenitors and cell size distribution analysis revealed accelerated adipogenesis in Wt pups born to Hetdb dams, accompanied by a higher accumulation of neonatal fat mass. In adulthood, whole body fat mass by NMR was higher in male (69%) and female (20%) Wt offspring born to Hetdb versus Wt pregnancies, along with adipocyte hypertrophy and hyperlipidemia (all P < 0.05). Lipidomic analyses by gas chromatography revealed an increased lipogenic index (16:0/18:2n6) after high-fat/fructose diet (HFFD). Postprandial insulin, ADIPO-IR, and ex vivo AT lipolytic responses to isoproterenol were all higher in Wt offspring born to Hetdb dams (P < 0.05). Intrauterine metabolic stimuli may direct a greater proportion of progenitors toward terminal differentiation, thereby predisposing to hypertrophy-induced adipocyte dysfunction.NEW & NOTEWORTHY This study reveals that accelerated adipogenesis during the perinatal window of adipose tissue development predisposes to later life hypertrophic adipocyte dysfunction, thereby compromising the buffering function of the subcutaneous depot.
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Affiliation(s)
- Anna Mikolajczak
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Nada A Sallam
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Faculty of Pharmacy, Cairo University, Giza, Egypt
| | - Radha D Singh
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Libin Cardiovascular Institute, Calgary, Alberta, Canada
| | - Taylor B Scheidl
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
- Libin Cardiovascular Institute, Calgary, Alberta, Canada
- Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Emma J Walsh
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sebastian Larion
- Division of Gastroenterology and Hepatology, Medical University of South Carolina, Charleston, South Carolina
| | - Carol Huang
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Jennifer A Thompson
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Libin Cardiovascular Institute, Calgary, Alberta, Canada
- Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
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15
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Despins CA, Brown SD, Robinson AV, Mungall AJ, Allen-Vercoe E, Holt RA. Modulation of the Host Cell Transcriptome and Epigenome by Fusobacterium nucleatum. mBio 2021; 12:e0206221. [PMID: 34700376 PMCID: PMC8546542 DOI: 10.1128/mbio.02062-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/16/2021] [Indexed: 02/03/2023] Open
Abstract
Fusobacterium nucleatum is a ubiquitous opportunistic pathogen with an emerging role as an oncomicrobe in colorectal cancer and other cancer settings. F. nucleatum can adhere to and invade host cells in a manner that varies across F. nucleatum strains and host cell phenotypes. Here, we performed pairwise cocultures between three F. nucleatum strains and two immortalized primary host cell types (human colonic epithelial [HCE] cells and human carotid artery endothelial [HCAE] cells) followed by transcriptome sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) to investigate transcriptional and epigenetic host cell responses. We observed that F. nucleatum-induced host cell transcriptional modulation involves strong upregulation of genes related to immune migration and inflammatory processes, such as TNF, CXCL8, CXCL1, and CCL20. Furthermore, we identified genes strongly upregulated in a cell line-specific manner. In HCE cells, overexpressed genes included UBD and DUOX2/DUOXA2, associated with p53 degradation-mediated proliferation and intestinal reactive oxygen species (ROS) production, respectively. In HCAE cells, overexpressed genes included EFNA1 and LIF, two genes commonly upregulated in colorectal cancer and associated with poor patient outcomes, and PTGS2 (COX2), a gene associated with the protective effect of aspirin in the colorectal cancer setting. Interestingly, we also observed downregulation of numerous histone modification genes upon F. nucleatum exposure. We used the ChIP-seq data to annotate chromatin states genome wide and found significant chromatin remodeling following F. nucleatum exposure in HCAE cells, with increased frequencies of active enhancer and low-signal/quiescent states. Thus, our results highlight increased inflammation and chemokine gene expression as conserved host cell responses to F. nucleatum exposure and extensive host cell epigenomic changes specific to host cell type. IMPORTANCE Fusobacterium nucleatum is a bacterium normally found in the healthy oral cavity but also has an emerging role in colorectal cancer and other cancer settings. The host-microbe interactions of F. nucleatum and its involvement in tumor initiation, progression, and treatment resistance are not fully understood. We explored host cell changes that occur in response to F. nucleatum. We identified key genes differentially expressed in response to various conditions of F. nucleatum exposure and determined that the conserved host cell response to F. nucleatum was dominated by increased inflammation and chemokine gene expression. Additionally, we found extensive host cell epigenomic changes as a novel aspect of host modulation associated with F. nucleatum exposure. These results extend our understanding of F. nucleatum as an emerging pathogen and highlight the importance of considering strain heterogeneity and host cell phenotypic variation when exploring pathogenic mechanisms of F. nucleatum.
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Affiliation(s)
- Cody A. Despins
- Canada’s Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Scott D. Brown
- Canada’s Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Avery V. Robinson
- Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Andrew J. Mungall
- Canada’s Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Emma Allen-Vercoe
- Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Robert A. Holt
- Canada’s Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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16
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Anand SP, Ding S, Tolbert WD, Prévost J, Richard J, Gil HM, Gendron-Lepage G, Cheung WF, Wang H, Pastora R, Saxena H, Wakarchuk W, Medjahed H, Wines BD, Hogarth M, Shaw GM, Martin MA, Burton DR, Hangartner L, Evans DT, Pazgier M, Cossar D, McLean MD, Finzi A. Enhanced Ability of Plant-Derived PGT121 Glycovariants To Eliminate HIV-1-Infected Cells. J Virol 2021; 95:e0079621. [PMID: 34232070 PMCID: PMC8387047 DOI: 10.1128/jvi.00796-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/25/2021] [Indexed: 12/14/2022] Open
Abstract
The activity of broadly neutralizing antibodies (bNAbs) targeting HIV-1 depends on pleiotropic functions, including viral neutralization and the elimination of HIV-1-infected cells. Several in vivo studies have suggested that passive administration of bNAbs represents a valuable strategy for the prevention or treatment of HIV-1. In addition, different strategies are currently being tested to scale up the production of bNAbs to obtain the large quantities of antibodies required for clinical trials. Production of antibodies in plants permits low-cost and large-scale production of valuable therapeutics; furthermore, pertinent to this work, it also includes an advanced glycoengineering platform. In this study, we used Nicotiana benthamiana to produce different Fc-glycovariants of a potent bNAb, PGT121, with near-homogeneous profiles and evaluated their antiviral activities. Structural analyses identified a close similarity in overall structure and glycosylation patterns of Fc regions for these plant-derived Abs and mammalian cell-derived Abs. When tested for Fc-effector activities, afucosylated PGT121 showed significantly enhanced FcγRIIIa interaction and antibody dependent cellular cytotoxicity (ADCC) against primary HIV-1-infected cells, both in vitro and ex vivo. However, the overall galactosylation profiles of plant PGT121 did not affect ADCC activities against infected primary CD4+ T cells. Our results suggest that the abrogation of the Fc N-linked glycan fucosylation of PGT121 is a worthwhile strategy to boost its Fc-effector functionality. IMPORTANCE PGT121 is a highly potent bNAb and its antiviral activities for HIV-1 prevention and therapy are currently being evaluated in clinical trials. The importance of its Fc-effector functions in clearing HIV-1-infected cells is also under investigation. Our results highlight enhanced Fc-effector activities of afucosylated PGT121 MAbs that could be important in a therapeutic context to accelerate infected cell clearance and slow disease progression. Future studies to evaluate the potential of plant-produced afucosylated PGT121 in controlling HIV-1 replication in vivo are warranted.
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Affiliation(s)
- Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
| | - William D. Tolbert
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Hwi Min Gil
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, Wisconsin, USA
- Department of Pathology and Laboratory Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | | | | | | | | | - Hirak Saxena
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Warren Wakarchuk
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | | | - Bruce D. Wines
- Immune Therapies Group, Burnet Institute, Melbourne, VIC, Australia
- Department of Clinical Pathology, University of Melbourne, Melbourne, VIC, Australia
- Department of Immunology and Pathology Monash University, Melbourne, VIC, Australia
| | - Mark Hogarth
- Immune Therapies Group, Burnet Institute, Melbourne, VIC, Australia
- Department of Clinical Pathology, University of Melbourne, Melbourne, VIC, Australia
- Department of Immunology and Pathology Monash University, Melbourne, VIC, Australia
| | - George M. Shaw
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Malcom A. Martin
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Dennis R. Burton
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, Harvard University, Cambridge, Massachusetts, USA
| | - Lars Hangartner
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California, USA
| | - David T. Evans
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, Wisconsin, USA
- Department of Pathology and Laboratory Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Doug Cossar
- PlantForm Corporation, Toronto, Ontario, Canada
| | | | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, Montreal, Quebec, Canada
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17
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Nguyen HT, Falzarano D, Gerdts V, Liu Q. Construction of a Noninfectious SARS-CoV-2 Replicon for Antiviral-Drug Testing and Gene Function Studies. J Virol 2021; 95:e0068721. [PMID: 34191580 PMCID: PMC8387049 DOI: 10.1128/jvi.00687-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/25/2021] [Indexed: 01/01/2023] Open
Abstract
The emerging coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread worldwide, resulting in global public health emergencies and economic crises. In the present study, a noninfectious and biosafety level 2 (BSL2)-compatible SARS-CoV-2 replicon expressing a nano luciferase (nLuc) reporter was constructed in a bacterial artificial chromosomal (BAC) vector by reverse genetics. The nLuc reporter is highly sensitive, easily quantifiable, and high throughput adaptable. Upon transfecting the SARS-CoV-2 replicon BAC plasmid DNA into Vero E6 cells, we could detect high levels of nLuc reporter activity and viral RNA transcript, suggesting the replication of the replicon. The replicon replication was further demonstrated by the findings that deleting nonstructural protein 15 or mutating its catalytic sites significantly reduced replicon replication, whereas providing the nucleocapsid protein in trans enhanced replicon replication in a dose-dependent manner. Finally, we showed that remdesivir, a U.S. Food and Drug Administration-approved antiviral drug, significantly inhibited the replication of the replicon, providing proof of principle for the application of our replicon as a useful tool for developing antivirals. Taken together, this study established a sensitive and BSL2-compatible reporter system in a single BAC plasmid for investigating the functions of SARS-CoV-2 proteins in viral replication and evaluating antiviral compounds. This should contribute to the global effort to combat this deadly viral pathogen. IMPORTANCE The COVID-19 pandemic caused by SARS-CoV-2 is having a catastrophic impact on human lives. Combatting the pandemic requires effective vaccines and antiviral drugs. In the present study, we developed a SARS-CoV-2 replicon system with a sensitive and easily quantifiable reporter. Unlike studies involving infectious SARS-CoV-2 virus that must be performed in a biosafety level 3 (BSL3) facility, the replicon is noninfectious and thus can be safely used in BSL2 laboratories. The replicon will provide a valuable tool for testing antiviral drugs and studying SARS-CoV-2 biology.
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Affiliation(s)
- Hai Trong Nguyen
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Darryl Falzarano
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Volker Gerdts
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Qiang Liu
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Vaccinology and Immunotherapeutics, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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18
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Vallée G, Norris P, Paszkowski P, Noyce RS, Evans DH. Vaccinia Virus Gene Acquisition through Nonhomologous Recombination. J Virol 2021; 95:e0031821. [PMID: 33910949 PMCID: PMC8223923 DOI: 10.1128/jvi.00318-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/19/2021] [Indexed: 01/04/2023] Open
Abstract
Many of the genes encoded by poxviruses are orthologs of cellular genes. These virus genes serve different purposes, but perhaps of most interest is the way some have been repurposed to inhibit the antiviral pathways that their cellular homologs still regulate. What is unclear is how these virus genes were acquired, although it is presumed to have been catalyzed by some form(s) of nonhomologous recombination (NHR). We used transfection assays and substrates encoding a fluorescent and drug-selectable marker to examine the NHR frequency in vaccinia virus (VAC)-infected cells. These studies showed that when cells were transfected with linear duplex DNAs bearing VAC N2L gene homology, it yielded a recombinant frequency (RF) of 6.7 × 10-4. In contrast, DNA lacking any VAC homology reduced the yield of recombinants ∼400-fold (RF = 1.6 × 10-6). DNA-RNA hybrids were also substrates, although homologous molecules yielded fewer recombinants (RF = 2.1 × 10-5), and nonhomologous substrates yielded only rare recombinants (RF ≤ 3 × 10-8). NHR was associated with genome rearrangements ranging from simple insertions with flanking sequence duplications to large-scale indels that produced helper-dependent viruses. The insert was often also partially duplicated and would rapidly rearrange through homologous recombination. Most of the virus-insert junctions exhibited little or no preexiting microhomology, although a few encoded VAC topoisomerase recognition sites (C/T·CCTT). These studies show that VAC can catalyze NHR through a process that may reflect a form of aberrant replication fork repair. Although it is less efficient than classical homologous recombination, the rates of NHR may still be high enough to drive virus evolution. IMPORTANCE Large DNA viruses sometimes interfere in antiviral defenses using repurposed and mutant forms of the cellular proteins that mediate these same reactions. Such virus orthologs of cellular genes were presumably captured through nonhomologous recombination, perhaps in the distant past, but nothing is known about the processes that might promote "gene capture" or even how often these events occur over the course of an infectious cycle. This study shows that nonhomologous recombination in vaccinia virus-infected cells is frequent enough to seed a small but still significant portion of novel recombinants into large populations of newly replicated virus particles. This offers a route by which a pool of virus might survey the host genome for sequences that offer a selective growth advantage and potentially drive discontinuous virus evolution (saltation) through the acquisition of adventitious traits.
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Affiliation(s)
- Greg Vallée
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Peter Norris
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick Paszkowski
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ryan S. Noyce
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - David H. Evans
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Li Ka Shing Institute of Virology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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19
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Jing L, Konoeda H, Keshavjee S, Liu M. Using nutrient-rich solutions and adding multiple cytoprotective agents as new strategies to develop lung preservation solutions. Am J Physiol Lung Cell Mol Physiol 2021; 320:L979-L989. [PMID: 33688744 DOI: 10.1152/ajplung.00516.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 03/05/2021] [Indexed: 11/22/2022] Open
Abstract
Commonly, donor lungs are preserved with low-potassium dextran glucose solution at low temperature. We hypothesized that adding nutrients and/or cytoprotective agents to preservation solutions improves donor lung quality. Human lung epithelial cells and human pulmonary microvascular endothelial cells cultured at 37°C with serum containing medium were switched to designated testing solutions at 4°C with 50% O2 for different cold ischemic time, followed by switching back to serum containing culture medium at 37°C to simulate reperfusion. We found that bicarbonate buffer system should be avoided in preservation solution. When pH was maintained at physiological levels, cell culture media showed better cell survival than in low-potassium dextran glucose solution. Phosphate-buffered cell culture media were further improved by adding colloid dextran 40. When rat donor lungs were preserved at 4°C for 24 h, phosphate-buffered Roswell Park Memorial Institute-1640 medium [RPMI-1640(p)] plus dextran 40 or adding cytoprotective agents (alpha 1 antitrypsin, raffinose, and glutathione) to low-potassium dextran glucose solution prevented alveolar wall swelling, apoptosis, activation of endothelial cells, and cellular edema. Using nutrient-rich solution and/or adding multiple cytoprotective agents is a new direction for designing and developing organ preservation solutions. Cell culture model, as a screening tool, reduces the use of animals and provides potential underlying mechanisms.
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Affiliation(s)
- Lei Jing
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Hisato Konoeda
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Shaf Keshavjee
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Surgery and Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Mingyao Liu
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Surgery and Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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20
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Xue YC, Ng CS, Mohamud Y, Fung G, Liu H, Bahreyni A, Zhang J, Luo H. FUS/TLS Suppresses Enterovirus Replication and Promotes Antiviral Innate Immune Responses. J Virol 2021; 95:e00304-21. [PMID: 33827951 PMCID: PMC8316056 DOI: 10.1128/jvi.00304-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/31/2021] [Indexed: 12/16/2022] Open
Abstract
During viral infection, the dynamic virus-host relationship is constantly in play. Many cellular proteins, such as RNA-binding proteins (RBPs), have been shown to mediate antiviral responses during viral infection. Here, we report that the RBP FUS/TLS (fused in sarcoma/translocated in liposarcoma) acts as a host-restricting factor against infection with coxsackievirus B3 (CVB3). Mechanistically, we found that deletion of FUS leads to increased viral RNA transcription and enhanced internal ribosome entry site (IRES)-driven translation, with no apparent impact on viral RNA stability. We further demonstrated that FUS physically interacts with the viral genome, which may contribute to direct inhibition of viral RNA transcription/translation. Moreover, we identified a novel function for FUS in regulating host innate immune response. We show that in the absence of FUS, gene expression of type I interferons and proinflammatory cytokines elicited by viral or bacterial infection is significantly impaired. Emerging evidence suggests a role for stress granules (SGs) in antiviral innate immunity. We further reveal that knockout of FUS abolishes the ability to form SGs upon CVB3 infection or poly(I·C) treatment. Finally, we show that, to avoid FUS-mediated antiviral response and innate immunity, CVB3 infection results in cytoplasmic mislocalization and cleavage of FUS through the enzymatic activity of viral proteases. Together, our findings in this study identify FUS as a novel host antiviral factor which restricts CVB3 replication through direct inhibition of viral RNA transcription and protein translation and through regulation of host antiviral innate immunity.IMPORTANCE Enteroviruses are common human pathogens, including those that cause myocarditis (coxsackievirus B3 [CVB3]), poliomyelitis (poliovirus), and hand, foot, and mouth disease (enterovirus 71). Understanding the virus-host interaction is crucial for developing means of treating and preventing diseases caused by these pathogens. In this study, we explored the interplay between the host RNA-binding protein FUS/TLS and CVB3 and found that FUS/TLS restricts CVB3 replication through direct inhibition of viral RNA transcription/translation and through regulation of cellular antiviral innate immunity. To impede the antiviral role of FUS, CVB3 targets FUS for mislocalization and cleavage. Findings from this study provide novel insights into interactions between CVB3 and FUS, which may lead to novel therapeutic interventions against enterovirus-induced diseases.
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Affiliation(s)
- Yuan Chao Xue
- Centre for Heart and Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chen Seng Ng
- Centre for Heart and Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yasir Mohamud
- Centre for Heart and Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gabriel Fung
- Centre for Heart and Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Huitao Liu
- Centre for Heart and Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Experimental Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amirhossein Bahreyni
- Centre for Heart and Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jingchun Zhang
- Centre for Heart and Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Honglin Luo
- Centre for Heart and Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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21
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Sadarangani M, Kollmann T, Bjornson G, Heath P, Clarke E, Marchant A, Levy O, Leuridan E, Ulloa-Gutierrez R, Cutland CL, Kampmann B, Chaithongwongwatthana S, Dinleyici E, van Damme P, Munoz FM. The Fifth International Neonatal and Maternal Immunization Symposium (INMIS 2019): Securing Protection for the Next Generation. mSphere 2021; 6:e00862-20. [PMID: 33504658 PMCID: PMC7885317 DOI: 10.1128/msphere.00862-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Despite significant progress in reaching some milestones of the United Nations Sustainable Development Goals, neonatal and early infant morbidity and mortality remain high, and maternal health remains suboptimal in many countries. Novel and improved preventative strategies with the potential to benefit pregnant women and their infants are needed, with maternal and neonatal immunization representing effective approaches. Experts from immunology, vaccinology, infectious diseases, clinicians, industry, public health, and vaccine-related social sciences convened at the 5th International Neonatal and Maternal Immunization Symposium (INMIS) in Vancouver, Canada, from 15 to 17 September 2019. We critically evaluated the lessons learned from recent clinical studies, presented cutting-edge scientific progress in maternal and neonatal immunology and vaccine development, and discussed maternal and neonatal immunization in the broader context of infectious disease epidemiology and public health. Focusing on practical aspects of research and implementation, we also discussed the safety, awareness, and perception of maternal immunization as an existing strategy to address the need to improve maternal and neonatal health worldwide. The symposium provided a comprehensive scientific and practical primer as well as an update for all those with an interest in maternal and neonatal infection, immunity, and vaccination. The summary presented here provides an update of the current status of progress in maternal and neonatal immunization.
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Affiliation(s)
- Manish Sadarangani
- Vaccine Evaluation Center, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
- Division of Infectious Diseases, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tobias Kollmann
- Telethon Kids Institute, Perth Children's Hospital, University of Western Perth, Perth, Australia
| | - Gordean Bjornson
- Vaccine Evaluation Center, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Paul Heath
- St. George's University of London, London, United Kingdom
| | - Ed Clarke
- Vaccines & Immunity Theme, Medical Research Council Unit, The Gambia, London School of Hygiene and Tropical Medicine (MRCG at LSHTM), Banjul, The Gambia
| | - Arnaud Marchant
- Institute for Medical Immunology, Université Libre de Bruxelles, Charleroi, Belgium
| | - Ofer Levy
- Precision Vaccines Program, Division of Infectious Diseases, Boston Children's Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
- Broad Institute of MIT & Harvard, Cambridge, Massachusetts, USA
| | - Elke Leuridan
- Centre for the Evaluation of Vaccination, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Rolando Ulloa-Gutierrez
- Hospital Nacional de Niños Dr. Carlos Sáenz Herrera, Centro de Ciencias Médicas C.C.S.S., San José, Costa Rica
| | - Clare L Cutland
- African Leadership in Vaccinology Expertise (ALIVE), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Beate Kampmann
- Vaccines & Immunity Theme, Medical Research Council Unit, The Gambia, London School of Hygiene and Tropical Medicine (MRCG at LSHTM), Banjul, The Gambia
- The Vaccine Centre, Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Surasith Chaithongwongwatthana
- Division of Infectious Disease in Gynecology and Obstetrics (InDiGO), Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Ener Dinleyici
- Eskisehir Osmangazi University, Faculty of Medicine, Eskisehir, Turkey
| | - Pierre van Damme
- Centre for the Evaluation of Vaccination, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Flor M Munoz
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
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22
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Monteil V, Dyczynski M, Lauschke VM, Kwon H, Wirnsberger G, Youhanna S, Zhang H, Slutsky AS, Hurtado del Pozo C, Horn M, Montserrat N, Penninger JM, Mirazimi A. Human soluble ACE2 improves the effect of remdesivir in SARS-CoV-2 infection. EMBO Mol Med 2021; 13:e13426. [PMID: 33179852 PMCID: PMC7799356 DOI: 10.15252/emmm.202013426] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/06/2020] [Accepted: 11/10/2020] [Indexed: 12/21/2022] Open
Abstract
There is a critical need for safe and effective drugs for COVID-19. Only remdesivir has received authorization for COVID-19 and has been shown to improve outcomes but not decrease mortality. However, the dose of remdesivir is limited by hepatic and kidney toxicity. ACE2 is the critical cell surface receptor for SARS-CoV-2. Here, we investigated additive effect of combination therapy using remdesivir with recombinant soluble ACE2 (high/low dose) on Vero E6 and kidney organoids, targeting two different modalities of SARS-CoV-2 life cycle: cell entry via its receptor ACE2 and intracellular viral RNA replication. This combination treatment markedly improved their therapeutic windows against SARS-CoV-2 in both models. By using single amino-acid resolution screening in haploid ES cells, we report a singular critical pathway required for remdesivir toxicity, namely, Adenylate Kinase 2. The data provided here demonstrate that combining two therapeutic modalities with different targets, common strategy in HIV treatment, exhibit strong additive effects at sub-toxic concentrations. Our data lay the groundwork for the study of combinatorial regimens in future COVID-19 clinical trials.
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Affiliation(s)
- Vanessa Monteil
- Department of Laboratory MedicineUnit of Clinical MicrobiologyKarolinska InstituteStockholmSweden
| | | | - Volker M Lauschke
- Department of Physiology and PharmacologyKarolinska InstituteStockholmSweden
| | | | | | - Sonia Youhanna
- Department of Physiology and PharmacologyKarolinska InstituteStockholmSweden
| | - Haibo Zhang
- Keenan Research Centre for Biomedical Science at Li Ka Shing Knowledge Institute of St. Michael’s HospitalUniversity of TorontoTorontoONCanada
| | - Arthur S Slutsky
- Keenan Research Centre for Biomedical Science at Li Ka Shing Knowledge Institute of St. Michael’s HospitalUniversity of TorontoTorontoONCanada
| | - Carmen Hurtado del Pozo
- Pluripotency for Organ RegenerationInstitute for Bioengineering of Catalonia (IBEC)The Barcelona Institute of Technology (BIST)BarcelonaSpain
- Catalan Institution for Research and Advanced Studies (ICREA)BarcelonaSpain
- Centro de Investigación Biomédica en Red en BioingenieríaBiomateriales y NanomedicinaMadridSpain
| | - Moritz Horn
- Acus Laboratories GmbHCologneGermany
- JLP Health GmbHViennaAustria
| | - Nuria Montserrat
- Pluripotency for Organ RegenerationInstitute for Bioengineering of Catalonia (IBEC)The Barcelona Institute of Technology (BIST)BarcelonaSpain
- Catalan Institution for Research and Advanced Studies (ICREA)BarcelonaSpain
- Centro de Investigación Biomédica en Red en BioingenieríaBiomateriales y NanomedicinaMadridSpain
| | - Josef M Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of SciencesViennaAustria
- Department of Medical GeneticsLife Sciences InstituteUniversity of British ColumbiaVancouverBCCanada
| | - Ali Mirazimi
- Department of Laboratory MedicineUnit of Clinical MicrobiologyKarolinska InstituteStockholmSweden
- National Veterinary InstituteUppsalaSweden
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23
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Rufai SB, McIntosh F, Poojary I, Chothe S, Sebastian A, Albert I, Praul C, Venkatesan M, Mahata G, Maity H, Dandapat P, Michael JS, Katani R, Kapur V, Behr MA. Complete Genome Sequence of Mycobacterium orygis Strain 51145. Microbiol Resour Announc 2021; 10:e01279-20. [PMID: 33414309 PMCID: PMC8407732 DOI: 10.1128/mra.01279-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 11/24/2020] [Indexed: 11/20/2022] Open
Abstract
We report the complete 4,352,172-bp genome sequence of Mycobacterium orygis strain 51145 assembled into a single circular chromosome. Comparative genomic analyses with other lineages of the Mycobacterium tuberculosis complex can provide insights into the biology, evolution, and epidemiology of this important group of pathogenic mycobacteria.
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Affiliation(s)
- Syed Beenish Rufai
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- McGill International TB Centre, Montreal, Quebec, Canada
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, Canada
| | - Fiona McIntosh
- McGill International TB Centre, Montreal, Quebec, Canada
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, Canada
| | - Indira Poojary
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Shubhada Chothe
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Aswathy Sebastian
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Istvan Albert
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Craig Praul
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Manigandan Venkatesan
- Department of Clinical Microbiology, Christian Medical College Vellore, Vellore, India
| | - Gibarni Mahata
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Hindol Maity
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
- Cisgen Biotech Discoveries, Chennai, India
| | - Premanshu Dandapat
- Indian Veterinary Research Institute, Eastern Region Station, Kolkata, West Bengal, India
| | - Joy Sarojini Michael
- Department of Clinical Microbiology, Christian Medical College Vellore, Vellore, India
| | - Robab Katani
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, Canada
- Department of Animal Science and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Vivek Kapur
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, Canada
- Department of Animal Science and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Marcel A Behr
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- McGill International TB Centre, Montreal, Quebec, Canada
- Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, Canada
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24
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Cheng D, Gao G, Di Lorenzo A, Jayne S, Hottiger MO, Richard S, Bedford MT. Genetic evidence for partial redundancy between the arginine methyltransferases CARM1 and PRMT6. J Biol Chem 2020; 295:17060-17070. [PMID: 33008887 PMCID: PMC7863876 DOI: 10.1074/jbc.ra120.014704] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/23/2020] [Indexed: 02/03/2023] Open
Abstract
CARM1 is a protein arginine methyltransferase (PRMT) that acts as a coactivator in a number of transcriptional programs. CARM1 orchestrates this coactivator activity in part by depositing the H3R17me2a histone mark in the vicinity of gene promoters that it regulates. However, the gross levels of H3R17me2a in CARM1 KO mice did not significantly decrease, indicating that other PRMT(s) may compensate for this loss. We thus performed a screen of type I PRMTs, which revealed that PRMT6 can also deposit the H3R17me2a mark in vitro CARM1 knockout mice are perinatally lethal and display a reduced fetal size, whereas PRMT6 null mice are viable, which permits the generation of double knockouts. Embryos that are null for both CARM1 and PRMT6 are noticeably smaller than CARM1 null embryos, providing in vivo evidence of redundancy. Mouse embryonic fibroblasts (MEFs) from the double knockout embryos display an absence of the H3R17me2a mark during mitosis and increased signs of DNA damage. Moreover, using the combination of CARM1 and PRMT6 inhibitors suppresses the cell proliferation of WT MEFs, suggesting a synergistic effect between CARM1 and PRMT6 inhibitions. These studies provide direct evidence that PRMT6 also deposits the H3R17me2a mark and acts redundantly with CARM1.
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Affiliation(s)
- Donghang Cheng
- Department of Pediatrics, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Guozhen Gao
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, Texas, USA
| | - Alessandra Di Lorenzo
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, Texas, USA
| | - Sandrine Jayne
- Ernest and Helen Scott Haematological Research Institute, Leicester Cancer Research Center, University of Leicester, Leicester, United Kingdom; Department of Molecular Mechanisms of Disease, University of Zurich, 8057, Zurich, Switzerland
| | - Michael O Hottiger
- Department of Molecular Mechanisms of Disease, University of Zurich, 8057, Zurich, Switzerland
| | - Stephane Richard
- Segal Cancer Center, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, and Departments of Medicine and Oncology, McGill University, Montréal, Québec, Canada
| | - Mark T Bedford
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, Texas, USA.
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25
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Baxter JC, Waples WG, Funnell BE. Nonspecific DNA binding by P1 ParA determines the distribution of plasmid partition and repressor activities. J Biol Chem 2020; 295:17298-17309. [PMID: 33055234 PMCID: PMC7863886 DOI: 10.1074/jbc.ra120.015642] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/10/2020] [Indexed: 12/13/2022] Open
Abstract
The faithful segregation, or "partition," of many low-copy number bacterial plasmids is driven by plasmid-encoded ATPases that are represented by the P1 plasmid ParA protein. ParA binds to the bacterial nucleoid via an ATP-dependent nonspecific DNA (nsDNA)-binding activity, which is essential for partition. ParA also has a site-specific DNA-binding activity to the par operator (parOP), which requires either ATP or ADP, and which is essential for it to act as a transcriptional repressor but is dispensable for partition. Here we examine how DNA binding by ParA contributes to the relative distribution of its plasmid partition and repressor activities, using a ParA with an alanine substitution at Arg351, a residue previously predicted to participate in site-specific DNA binding. In vivo, the parAR351A allele is compromised for partition, but its repressor activity is dramatically improved so that it behaves as a "super-repressor." In vitro, ParAR351A binds and hydrolyzes ATP, and undergoes a specific conformational change required for nsDNA binding, but its nsDNA-binding activity is significantly damaged. This defect in turn significantly reduces the assembly and stability of partition complexes formed by the interaction of ParA with ParB, the centromere-binding protein, and DNA. In contrast, the R351A change shows only a mild defect in site-specific DNA binding. We conclude that the partition defect is due to altered nsDNA binding kinetics and affinity for the bacterial chromosome. Furthermore, the super-repressor phenotype is explained by an increased pool of non-nucleoid bound ParA that is competent to bind parOP and repress transcription.
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Affiliation(s)
- Jamie C Baxter
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario Canada
| | - William G Waples
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario Canada
| | - Barbara E Funnell
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario Canada.
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26
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Liu Y, Trnka MJ, Guan S, Kwon D, Kim DH, Chen JJ, Greer PA, Burlingame AL, Correia MA. A Novel Mechanism for NF-κB-activation via IκB-aggregation: Implications for Hepatic Mallory-Denk-Body Induced Inflammation. Mol Cell Proteomics 2020; 19:1968-1986. [PMID: 32912968 PMCID: PMC7710137 DOI: 10.1074/mcp.ra120.002316] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Indexed: 11/06/2022] Open
Abstract
Mallory-Denk-bodies (MDBs) are hepatic protein aggregates associated with inflammation both clinically and in MDB-inducing models. Similar protein aggregation in neurodegenerative diseases also triggers inflammation and NF-κB activation. However, the precise mechanism that links protein aggregation to NF-κB-activation and inflammatory response remains unclear. Herein we find that treating primary hepatocytes with MDB-inducing agents (N-methylprotoporphyrin (NMPP), protoporphyrin IX (PPIX), or Zinc-protoporphyrin IX (ZnPP)) elicited an IκBα-loss with consequent NF-κB activation. Four known mechanisms of IκBα-loss i.e. the canonical ubiquitin-dependent proteasomal degradation (UPD), autophagic-lysosomal degradation, calpain degradation and translational inhibition, were all probed and excluded. Immunofluorescence analyses of ZnPP-treated cells coupled with 8 M urea/CHAPS-extraction revealed that this IκBα-loss was due to its sequestration along with IκBβ into insoluble aggregates, thereby releasing NF-κB. Through affinity pulldown, proximity biotinylation by antibody recognition, and other proteomic analyses, we verified that NF-κB subunit p65, which stably interacts with IκBα under normal conditions, no longer binds to it upon ZnPP-treatment. Additionally, we identified 10 proteins that interact with IκBα under baseline conditions, aggregate upon ZnPP-treatment, and maintain the interaction with IκBα after ZnPP-treatment, either by cosequestering into insoluble aggregates or through a different mechanism. Of these 10 proteins, the nucleoporins Nup153 and Nup358/RanBP2 were identified through RNA-interference, as mediators of IκBα-nuclear import. The concurrent aggregation of IκBα, NUP153, and RanBP2 upon ZnPP-treatment, synergistically precluded the nuclear entry of IκBα and its consequent binding and termination of NF-κB activation. This novel mechanism may account for the protein aggregate-induced inflammation observed in liver diseases, thus identifying novel targets for therapeutic intervention. Because of inherent commonalities this MDB cell model is a bona fide protoporphyric model, making these findings equally relevant to the liver inflammation associated with clinical protoporphyria.
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Affiliation(s)
- Yi Liu
- Departments of Cellular & Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA
| | - Michael J Trnka
- Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Shenheng Guan
- Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Doyoung Kwon
- Departments of Cellular & Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA
| | - Do-Hyung Kim
- Departments of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, USA
| | - J-J Chen
- Institute for Medical Engineering and Science, MIT, Cambridge, Massachusetts, USA
| | - Peter A Greer
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, Canada
| | - A L Burlingame
- Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Maria Almira Correia
- Departments of Cellular & Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA; Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA; Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, USA; The Liver Center, University of California San Francisco, San Francisco, California, USA.
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Khlghatyan J, Evstratova A, Bozoyan L, Chamberland S, Chatterjee D, Marakhovskaia A, Soares Silva T, Toth K, Mongrain V, Beaulieu J. Fxr1 regulates sleep and synaptic homeostasis. EMBO J 2020; 39:e103864. [PMID: 32893934 PMCID: PMC7604579 DOI: 10.15252/embj.2019103864] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 08/01/2020] [Accepted: 08/06/2020] [Indexed: 12/22/2022] Open
Abstract
The fragile X autosomal homolog 1 (Fxr1) is regulated by lithium and has been GWAS-associated with schizophrenia and insomnia. Homeostatic regulation of synaptic strength is essential for the maintenance of brain functions and involves both cell-autonomous and system-level processes such as sleep. We examined the contribution of Fxr1 to cell-autonomous homeostatic synaptic scaling and neuronal responses to sleep loss, using a combination of gene overexpression and Crispr/Cas9-mediated somatic knockouts to modulate gene expression. Our findings indicate that Fxr1 is downregulated during both scaling and sleep deprivation via a glycogen synthase kinase 3 beta (GSK3β)-dependent mechanism. In both conditions, downregulation of Fxr1 is essential for the homeostatic modulation of surface AMPA receptors and synaptic strength. Preventing the downregulation of Fxr1 during sleep deprivation results in altered EEG signatures. Furthermore, sequencing of neuronal translatomes revealed the contribution of Fxr1 to changes induced by sleep deprivation. These findings uncover a role of Fxr1 as a shared signaling hub between cell-autonomous homeostatic plasticity and system-level responses to sleep loss, with potential implications for neuropsychiatric illnesses and treatments.
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Affiliation(s)
- Jivan Khlghatyan
- Department of Pharmacology & ToxicologyUniversity of TorontoTorontoONCanada
- Department of Psychiatry and NeuroscienceFaculty of MedicineUniversité LavalQuébec‐CityQCCanada
- Present address:
Department of NeuroscienceNovartis Institutes for Biomedical ResearchCambridgeMAUSA
| | - Alesya Evstratova
- Department of Pharmacology & ToxicologyUniversity of TorontoTorontoONCanada
| | - Lusine Bozoyan
- Department of Pharmacology & ToxicologyUniversity of TorontoTorontoONCanada
| | - Simon Chamberland
- Department of Psychiatry and NeuroscienceFaculty of MedicineUniversité LavalQuébec‐CityQCCanada
- Present address:
NYU Neuroscience InstituteLangone Medical CenterNew York UniversityNew YorkNYUSA
| | | | | | - Tiago Soares Silva
- Department of Pharmacology & ToxicologyUniversity of TorontoTorontoONCanada
| | - Katalin Toth
- Department of Cellular and Molecular MedicineFaculty of MedicineUniversity of OttawaOttawaONCanada
| | - Valerie Mongrain
- Department of NeuroscienceUniversité de Montréal and Center for Advanced Research in Sleep MedicineHôpital du Sacré‐Coeur de Montréal (CIUSSS‐NIM)MontrealQCCanada
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28
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Burrows JTA, Depierreux D, Nibert ML, Pearson BJ. A Novel Taxon of Monosegmented Double-Stranded RNA Viruses Endemic to Triclad Flatworms. J Virol 2020; 94:e00623-20. [PMID: 32907972 PMCID: PMC7592200 DOI: 10.1128/jvi.00623-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 09/01/2020] [Indexed: 12/12/2022] Open
Abstract
Freshwater planarians, flatworms from order Tricladida, are experimental models of stem cell biology and tissue regeneration. An aspect of their biology that remains less well studied is their relationship with viruses that may infect them. In this study, we identified a taxon of monosegmented double-stranded RNA (dsRNA) viruses in five planarian species, including the well-characterized model Schmidtea mediterranea Sequences for the S. mediterranea virus (abbreviated SmedTV for S. mediterranea tricladivirus) were found in public transcriptome data from multiple institutions, indicating that SmedTV is prevalent in S. mediterranea lab colonies, though without causing evident disease. The presence of SmedTV in discrete cells was shown through in situ hybridization methods for detecting the viral RNA. SmedTV-staining cells were found to be concentrated in neural structures (eyes and brain) but were also scattered in other worm tissues as well. In contrast, few SmedTV-staining cells were seen in stem cell compartments (also consistent with RNA sequencing data) or early blastema tissue. RNA interference (RNAi) targeted to the SmedTV sequence led to apparent cure of infection, though effects on worm health or behavior were not observed. Efforts to transmit SmedTV horizontally through microinjection were unsuccessful. Based on these findings, we conclude that SmedTV infects S. mediterranea in a persistent manner and undergoes vertical transmission to progeny worms during serial passage in lab colonies. The utility of S. mediterranea as a regeneration model, coupled with the apparent capacity of SmedTV to evade normal host immune/RNAi defenses under standard conditions, argues that further studies are warranted to explore this newly recognized virus-host system.IMPORTANCE Planarians are freshwater flatworms, related more distantly to tapeworms and flukes, and have been developed as models to study the molecular mechanisms of stem cell biology and tissue regeneration. These worms live in aquatic environments, where they are likely to encounter a variety of viruses, bacteria, and eukaryotic organisms with pathogenic potential. How the planarian immune system has evolved to cope with these potential pathogens is not well understood, and only two types of planarian viruses have been described to date. Here, we report discovery and inaugural studies of a novel taxon of dsRNA viruses in five different planarian species. The virus in the best-characterized model species, Schmidtea mediterranea, appears to persist long term in that host while avoiding endogenous antiviral or RNAi mechanisms. The S. mediterranea virus-host system thus seems to offer opportunity for gaining new insights into host defenses and their evolution in an important lab model.
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Affiliation(s)
- Jeffrey T A Burrows
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario, Canada
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Delphine Depierreux
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Max L Nibert
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Bret J Pearson
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario, Canada
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
- University of Toronto, Department of Molecular Genetics, Toronto, Ontario, Canada
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29
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Abstract
The mechanisms by which bacteria sense and respond to surface attachment have long been a mystery. Our understanding of the structure and dynamics of bacterial appendages, notably type IV pili (T4P), provided new insights into the potential ways that bacteria sense surfaces. T4P are ubiquitous, retractable hair-like adhesins that until recently were difficult to image in the absence of fixation due to their nanoscale size. This review focuses on recent microscopy innovations used to visualize T4P in live cells to reveal the dynamics of their retraction and extension. We discuss recently proposed mechanisms by which T4P facilitate bacterial surface sensing, including the role of surface-exposed PilY1, two-component signal transduction pathways, force-induced structural modifications of the major pilin, and altered dynamics of the T4P motor complex.
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Affiliation(s)
- Katherine J Graham
- Department of Biochemistry and Biomedical Sciences, and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton ON Canada L8S4K1
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences, and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton ON Canada L8S4K1
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30
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Beaudoin-Bussières G, Laumaea A, Anand SP, Prévost J, Gasser R, Goyette G, Medjahed H, Perreault J, Tremblay T, Lewin A, Gokool L, Morrisseau C, Bégin P, Tremblay C, Martel-Laferrière V, Kaufmann DE, Richard J, Bazin R, Finzi A. Decline of Humoral Responses against SARS-CoV-2 Spike in Convalescent Individuals. mBio 2020; 11:e02590-20. [PMID: 33067385 PMCID: PMC7569150 DOI: 10.1128/mbio.02590-20] [Citation(s) in RCA: 146] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 09/29/2020] [Indexed: 01/06/2023] Open
Abstract
In the absence of effective vaccines and with limited therapeutic options, convalescent plasma is being collected across the globe for potential transfusion to coronavirus disease 2019 (COVID-19) patients. The therapy has been deemed safe, and several clinical trials assessing its efficacy are ongoing. While it remains to be formally proven, the presence of neutralizing antibodies is thought to play a positive role in the efficacy of this treatment. Indeed, neutralizing titers of ≥1:160 have been recommended in some convalescent plasma trials for inclusion. Here, we performed repeated analyses at 1-month intervals on 31 convalescent individuals to evaluate how the humoral responses against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike glycoprotein, including neutralization, evolve over time. We observed that the levels of receptor-binding-domain (RBD)-specific IgG and IgA slightly decreased between 6 and 10 weeks after the onset of symptoms but that RBD-specific IgM levels decreased much more abruptly. Similarly, we observed a significant decrease in the capacity of convalescent plasma to neutralize pseudoparticles bearing wild-type SARS-CoV-2 S or its D614G variant. If neutralization activity proves to be an important factor in the clinical efficacy of convalescent plasma transfer, our results suggest that plasma from convalescent donors should be recovered rapidly after resolution of symptoms.IMPORTANCE While waiting for an efficient vaccine to protect against SARS-CoV-2 infection, alternative approaches to treat or prevent acute COVID-19 are urgently needed. Transfusion of convalescent plasma to treat COVID-19 patients is currently being explored; neutralizing activity in convalescent plasma is thought to play a central role in the efficacy of this treatment. Here, we observed that plasma neutralization activity decreased a few weeks after the onset of the symptoms. If neutralizing activity is required for the efficacy of convalescent plasma transfer, our results suggest that convalescent plasma should be recovered rapidly after the donor recovers from active infection.
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Affiliation(s)
- Guillaume Beaudoin-Bussières
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Annemarie Laumaea
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Sai Priya Anand
- Centre de Recherche du CHUM, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Romain Gasser
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | | | - Josée Perreault
- Affaires Médicales et Innovation, Héma-Québec, Montreal, Quebec, Canada
| | - Tony Tremblay
- Affaires Médicales et Innovation, Héma-Québec, Montreal, Quebec, Canada
| | - Antoine Lewin
- Affaires Médicales et Innovation, Héma-Québec, Montreal, Quebec, Canada
| | | | | | - Philippe Bégin
- Centre de Recherche du CHUM, Quebec, Canada
- CHU Ste-Justine, Montreal, Quebec, Canada
| | - Cécile Tremblay
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Valérie Martel-Laferrière
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Daniel E Kaufmann
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Jonathan Richard
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Renée Bazin
- Affaires Médicales et Innovation, Héma-Québec, Montreal, Quebec, Canada
| | - Andrés Finzi
- Centre de Recherche du CHUM, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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31
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Bauer KC, Huus KE, Brown EM, Bozorgmehr T, Petersen C, Cirstea MS, Woodward SE, McCoy J, Hun J, Pamplona R, Ayala V, Finlay BB. Dietary Intervention Reverses Fatty Liver and Altered Gut Microbiota during Early-Life Undernutrition. mSystems 2020; 5:e00499-20. [PMID: 32900869 PMCID: PMC7483509 DOI: 10.1128/msystems.00499-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/01/2020] [Indexed: 01/04/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), largely studied as a condition of overnutrition, also presents in undernourished populations. Like NAFLD, undernutrition disrupts systemic metabolism and has been linked to gut microbiota dysbiosis. Indeed, chronic exposures to fecal microbes contribute to undernutrition pathology in regions with poor sanitation. Despite a growing prevalence of fatty liver disease, the influence of undernutrition and the gut microbiota remain largely unexplored. Here, we utilize an established murine model (C57BL/6J mice placed on a malnourished diet that received iterative Escherichia coli/Bacteroidales gavage [MBG mice]) that combines a protein/fat-deficient diet and iterative exposure to specific, fecal microbes. Fecal-oral contamination exacerbates triglyceride accumulation in undernourished mice. MBG livers exhibit diffuse lipidosis accompanied by striking shifts in fatty acid, glycerophospholipid, and retinol metabolism. Multiomic analyses revealed metabolomic pathways linked to the undernourished gut microbiome and hepatic steatosis, including phenylacetate metabolism. Intriguingly, fatty liver features were observed only in the early-life, but not adult, MBG model despite similar liver metabolomic profiles. Importantly, we demonstrate that dietary intervention largely mitigates aberrant metabolomic and microbiome features in MBG mice. These findings indicate a crucial window in early-life development that, when disrupted by nutritional deficiency, may significantly influence liver function. Our work provides a multifaceted study of how diet and gut microbes inform fatty liver progression and reversal during undernutrition.IMPORTANCE Nonalcoholic fatty liver disease (NAFLD) remains a global epidemic, but it is often studied in the context of obesity and aging. Nutritional deficits, however, also trigger hepatic steatosis, influencing health trajectories in undernourished pediatric populations. Here, we report that exposure to specific gut microbes impacts fatty liver pathology in mice fed a protein/fat-deficient diet. We utilize a multiomics approach to (i) characterize NAFLD in the context of early undernutrition and (ii) examine the impact of diet and gut microbes in the pathology and reversal of hepatic steatosis. We provide compelling evidence that an early-life, critical development window facilitates undernutrition-induced fatty liver pathology. Moreover, we demonstrate that sustained dietary intervention largely reverses fatty liver features and microbiome shifts observed during early-life malnutrition.
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Affiliation(s)
- K C Bauer
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Microbiology and Immunology Department, University of British Columbia, Vancouver, British Columbia, Canada
| | - K E Huus
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Microbiology and Immunology Department, University of British Columbia, Vancouver, British Columbia, Canada
| | - E M Brown
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Microbiology and Immunology Department, University of British Columbia, Vancouver, British Columbia, Canada
| | - T Bozorgmehr
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - C Petersen
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - M S Cirstea
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Microbiology and Immunology Department, University of British Columbia, Vancouver, British Columbia, Canada
| | - S E Woodward
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Microbiology and Immunology Department, University of British Columbia, Vancouver, British Columbia, Canada
| | - J McCoy
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - J Hun
- The Metabolomics Innovation Centre, University of Victoria, British Columbia, Canada
| | - R Pamplona
- Institut de Recerca Biomèdica de Lleida (IRB-Lleida), Lleida, Spain
- Department of Metabolomic Physiology, Universitat de Lleida, Lleida, Spain
| | - V Ayala
- Institut de Recerca Biomèdica de Lleida (IRB-Lleida), Lleida, Spain
- Department of Metabolomic Physiology, Universitat de Lleida, Lleida, Spain
| | - B B Finlay
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Microbiology and Immunology Department, University of British Columbia, Vancouver, British Columbia, Canada
- Biochemistry and Molecular Biology Department, University of British Columbia, Vancouver, Canada
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32
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Marmont LS, Whitfield GB, Pfoh R, Williams RJ, Randall TE, Ostaszewski A, Razvi E, Groves RA, Robinson H, Nitz M, Parsek MR, Lewis IA, Whitney JC, Harrison JJ, Howell PL. PelX is a UDP- N-acetylglucosamine C4-epimerase involved in Pel polysaccharide-dependent biofilm formation. J Biol Chem 2020; 295:11949-11962. [PMID: 32601062 PMCID: PMC7443510 DOI: 10.1074/jbc.ra120.014555] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/24/2020] [Indexed: 12/15/2022] Open
Abstract
Pel is a GalNAc-rich bacterial polysaccharide that contributes to the structure and function of Pseudomonas aeruginosa biofilms. The pelABCDEFG operon is highly conserved among diverse bacterial species, and Pel may therefore be a widespread biofilm determinant. Previous annotation of pel gene clusters has helped us identify an additional gene, pelX, that is present adjacent to pelABCDEFG in >100 different bacterial species. The pelX gene is predicted to encode a member of the short-chain dehydrogenase/reductase (SDR) superfamily, but its potential role in Pel-dependent biofilm formation is unknown. Herein, we have used Pseudomonas protegens Pf-5 as a model to elucidate PelX function as Pseudomonas aeruginosa lacks a pelX homologue in its pel gene cluster. We found that P. protegens forms Pel-dependent biofilms; however, despite expression of pelX under these conditions, biofilm formation was unaffected in a ΔpelX strain. This observation led us to identify a pelX paralogue, PFL_5533, which we designate here PgnE, that appears to be functionally redundant to pelX In line with this, a ΔpelX ΔpgnE double mutant was substantially impaired in its ability to form Pel-dependent biofilms. To understand the molecular basis for this observation, we determined the structure of PelX to 2.1 Å resolution. The structure revealed that PelX resembles UDP-GlcNAc C4-epimerases. Using 1H NMR analysis, we show that PelX catalyzes the epimerization between UDP-GlcNAc and UDP-GalNAc. Our results indicate that Pel-dependent biofilm formation requires a UDP-GlcNAc C4-epimerase that generates the UDP-GalNAc precursors required by the Pel synthase machinery for polymer production.
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Affiliation(s)
- Lindsey S Marmont
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Gregory B Whitfield
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Roland Pfoh
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rohan J Williams
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Trevor E Randall
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | | | - Erum Razvi
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Ryan A Groves
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Howard Robinson
- Photon Science Division, Brookhaven National Laboratory, Upton, New York, USA
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Ian A Lewis
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - John C Whitney
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Joe J Harrison
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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Slater CL, Winogrodzki J, Fraile-Ribot PA, Oliver A, Khajehpour M, Mark BL. Adding Insult to Injury: Mechanistic Basis for How AmpC Mutations Allow Pseudomonas aeruginosa To Accelerate Cephalosporin Hydrolysis and Evade Avibactam. Antimicrob Agents Chemother 2020; 64:e00894-20. [PMID: 32660987 PMCID: PMC7449160 DOI: 10.1128/aac.00894-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/01/2020] [Indexed: 12/27/2022] Open
Abstract
Pseudomonas aeruginosa is a leading cause of nosocomial infections worldwide and notorious for its broad-spectrum resistance to antibiotics. A key mechanism that provides extensive resistance to β-lactam antibiotics is the inducible expression of AmpC β-lactamase. Recently, a number of clinical isolates expressing mutated forms of AmpC have been found to be clinically resistant to the antipseudomonal β-lactam-β-lactamase inhibitor (BLI) combinations ceftolozane-tazobactam and ceftazidime-avibactam. Here, we compare the enzymatic activity of wild-type (WT) AmpC from PAO1 to those of four of these reported AmpC mutants, bearing mutations E247K (a change of E to K at position 247), G183D, T96I, and ΔG229-E247 (a deletion from position 229 to 247), to gain detailed insights into how these mutations allow the circumvention of these clinically vital antibiotic-inhibitor combinations. We found that these mutations exert a 2-fold effect on the catalytic cycle of AmpC. First, they reduce the stability of the enzyme, thereby increasing its flexibility. This appears to increase the rate of deacylation of the enzyme-bound β-lactam, resulting in greater catalytic efficiencies toward ceftolozane and ceftazidime. Second, these mutations reduce the affinity of avibactam for AmpC by increasing the apparent activation barrier of the enzyme acylation step. This does not influence the catalytic turnover of ceftolozane and ceftazidime significantly, as deacylation is the rate-limiting step for the breakdown of these antibiotic substrates. It is remarkable that these mutations enhance the catalytic efficiency of AmpC toward ceftolozane and ceftazidime while simultaneously reducing susceptibility to inhibition by avibactam. Knowledge gained from the molecular analysis of these and other AmpC resistance mutants will, we believe, aid in the design of β-lactams and BLIs with reduced susceptibility to mutational resistance.
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Affiliation(s)
- Cole L Slater
- Department of Microbiology, University of Manitoba, Winnipeg, Canada
| | | | - Pablo A Fraile-Ribot
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain
- Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Antonio Oliver
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain
- Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | | | - Brian L Mark
- Department of Microbiology, University of Manitoba, Winnipeg, Canada
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Kelly JA, Olson AN, Neupane K, Munshi S, San Emeterio J, Pollack L, Woodside MT, Dinman JD. Structural and functional conservation of the programmed -1 ribosomal frameshift signal of SARS coronavirus 2 (SARS-CoV-2). J Biol Chem 2020; 295:10741-10748. [PMID: 32571880 PMCID: PMC7397099 DOI: 10.1074/jbc.ac120.013449] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/19/2020] [Indexed: 12/17/2022] Open
Abstract
Approximately 17 years after the severe acute respiratory syndrome coronavirus (SARS-CoV) epidemic, the world is currently facing the COVID-19 pandemic caused by SARS corona virus 2 (SARS-CoV-2). According to the most optimistic projections, it will take more than a year to develop a vaccine, so the best short-term strategy may lie in identifying virus-specific targets for small molecule-based interventions. All coronaviruses utilize a molecular mechanism called programmed -1 ribosomal frameshift (-1 PRF) to control the relative expression of their proteins. Previous analyses of SARS-CoV have revealed that it employs a structurally unique three-stemmed mRNA pseudoknot that stimulates high -1 PRF rates and that it also harbors a -1 PRF attenuation element. Altering -1 PRF activity impairs virus replication, suggesting that this activity may be therapeutically targeted. Here, we comparatively analyzed the SARS-CoV and SARS-CoV-2 frameshift signals. Structural and functional analyses revealed that both elements promote similar -1 PRF rates and that silent coding mutations in the slippery sites and in all three stems of the pseudoknot strongly ablate -1 PRF activity. We noted that the upstream attenuator hairpin activity is also functionally retained in both viruses, despite differences in the primary sequence in this region. Small-angle X-ray scattering analyses indicated that the pseudoknots in SARS-CoV and SARS-CoV-2 have the same conformation. Finally, a small molecule previously shown to bind the SARS-CoV pseudoknot and inhibit -1 PRF was similarly effective against -1 PRF in SARS-CoV-2, suggesting that such frameshift inhibitors may be promising lead compounds to combat the current COVID-19 pandemic.
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Affiliation(s)
- Jamie A Kelly
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
| | - Alexandra N Olson
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
| | - Krishna Neupane
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Sneha Munshi
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Josue San Emeterio
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, USA
| | | | - Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
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Sexton DL, Herlihey FA, Brott AS, Crisante DA, Shepherdson E, Clarke AJ, Elliot MA. Roles of LysM and LytM domains in resuscitation-promoting factor (Rpf) activity and Rpf-mediated peptidoglycan cleavage and dormant spore reactivation. J Biol Chem 2020; 295:9171-9182. [PMID: 32434927 PMCID: PMC7335776 DOI: 10.1074/jbc.ra120.013994] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/15/2020] [Indexed: 11/06/2022] Open
Abstract
Bacterial dormancy can take many forms, including formation of Bacillus endospores, Streptomyces exospores, and metabolically latent Mycobacterium cells. In the actinobacteria, including the streptomycetes and mycobacteria, the rapid resuscitation from a dormant state requires the activities of a family of cell-wall lytic enzymes called resuscitation-promoting factors (Rpfs). Whether Rpf activity promotes resuscitation by generating peptidoglycan fragments (muropeptides) that function as signaling molecules for spore germination or by simply remodeling the dormant cell wall has been the subject of much debate. Here, to address this question, we used mutagenesis and peptidoglycan binding and cleavage assays to first gain broader insight into the biochemical function of diverse Rpf enzymes. We show that their LysM and LytM domains enhance Rpf enzyme activity; their LytM domain and, in some cases their LysM domain, also promoted peptidoglycan binding. We further demonstrate that the Rpfs function as endo-acting lytic transglycosylases, cleaving within the peptidoglycan backbone. We also found that unlike in other systems, Rpf activity in the streptomycetes is not correlated with peptidoglycan-responsive Ser/Thr kinases for cell signaling, and the germination of rpf mutant strains could not be stimulated by the addition of known germinants. Collectively, these results suggest that in Streptomyces, Rpfs have a structural rather than signaling function during spore germination, and that in the actinobacteria, any signaling function associated with spore resuscitation requires the activity of additional yet to be identified enzymes.
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Affiliation(s)
- Danielle L Sexton
- Michael G. DeGroote Institute for Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Canada
| | - Francesca A Herlihey
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Ashley S Brott
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - David A Crisante
- Michael G. DeGroote Institute for Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Canada
| | - Evan Shepherdson
- Michael G. DeGroote Institute for Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Canada
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Marie A Elliot
- Michael G. DeGroote Institute for Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Canada.
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Umviligihozo G, Cobarrubias KD, Chandrarathna S, Jin SW, Reddy N, Byakwaga H, Muzoora C, Bwana MB, Lee GQ, Hunt PW, Martin JN, Brumme CJ, Bangsberg DR, Karita E, Allen S, Hunter E, Ndung'u T, Brumme ZL, Brockman MA. Differential Vpu-Mediated CD4 and Tetherin Downregulation Functions among Major HIV-1 Group M Subtypes. J Virol 2020; 94:e00293-20. [PMID: 32376625 PMCID: PMC7343213 DOI: 10.1128/jvi.00293-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 04/30/2020] [Indexed: 12/12/2022] Open
Abstract
Downregulation of BST-2/tetherin and CD4 by HIV-1 viral protein U (Vpu) promotes viral egress and allows infected cells to evade host immunity. Little is known however about the natural variability in these Vpu functions among the genetically diverse viral subtypes that contribute to the HIV-1 pandemic. We collected Vpu isolates from 332 treatment-naive individuals living with chronic HIV-1 infection in Uganda, Rwanda, South Africa, and Canada. Together, these Vpu isolates represent four major HIV-1 group M subtypes (A [n = 63], B [n = 84], C [n = 94], and D [n = 59]) plus intersubtype recombinants and uncommon strains (n = 32). The ability of each Vpu clone to downregulate endogenous CD4 and tetherin was quantified using flow cytometry following transfection into an immortalized T-cell line and compared to that of a reference Vpu clone derived from HIV-1 subtype B NL4.3. Overall, the median CD4 downregulation function of natural Vpu isolates was similar to that of NL4.3 (1.01 [interquartile range {IQR}, 0.86 to 1.18]), while the median tetherin downregulation function was moderately lower than that of NL4.3 (0.90 [0.79 to 0.97]). Both Vpu functions varied significantly among HIV-1 subtypes (Kruskal-Wallis P < 0.0001). Specifically, subtype C clones exhibited the lowest CD4 and tetherin downregulation activities, while subtype D and B clones were most functional for both activities. We also identified Vpu polymorphisms associated with CD4 or tetherin downregulation function and validated six of these using site-directed mutagenesis. Our results highlight the marked extent to which Vpu function varies among global HIV-1 strains, raising the possibility that natural variation in this accessory protein may contribute to viral pathogenesis and/or spread.IMPORTANCE The HIV-1 accessory protein Vpu enhances viral spread by downregulating CD4 and BST-2/tetherin on the surface of infected cells. Natural variability in these Vpu functions may contribute to HIV-1 pathogenesis, but this has not been investigated among the diverse viral subtypes that contribute to the HIV-1 pandemic. In this study, we found that Vpu function differs significantly among HIV-1 subtypes A, B, C, and D. On average, subtype C clones displayed the lowest ability to downregulate both CD4 and tetherin, while subtype B and D clones were more functional. We also identified Vpu polymorphisms that associate with functional differences among HIV-1 isolates and subtypes. Our study suggests that genetic diversity in Vpu may play an important role in the differential pathogenesis and/or spread of HIV-1.
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Affiliation(s)
- Gisele Umviligihozo
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Kyle D Cobarrubias
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Sandali Chandrarathna
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Steven W Jin
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Nicole Reddy
- University of KwaZulu-Natal, Durban, South Africa
- Africa Health Research Institute, Durban, South Africa
| | - Helen Byakwaga
- Mbarara University of Science and Technology, Mbarara, Uganda
- University of California, San Francisco, California, USA
| | - Conrad Muzoora
- Mbarara University of Science and Technology, Mbarara, Uganda
| | - Mwebesa B Bwana
- Mbarara University of Science and Technology, Mbarara, Uganda
| | - Guinevere Q Lee
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
| | - Peter W Hunt
- University of California, San Francisco, California, USA
| | - Jeff N Martin
- University of California, San Francisco, California, USA
| | - Chanson J Brumme
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
- University of British Columbia, Vancouver, British Columbia, Canada
| | - David R Bangsberg
- Oregon Health and Science University-Portland State University School of Public Health, Portland, Oregon, USA
| | - Etienne Karita
- Rwanda Zambia HIV Research Group-Projet San Francisco, Kigali, Rwanda
| | - Susan Allen
- Rwanda Zambia HIV Research Group-Projet San Francisco, Kigali, Rwanda
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, USA
- Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | - Eric Hunter
- Rwanda Zambia HIV Research Group-Projet San Francisco, Kigali, Rwanda
- Emory Vaccine Center at Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Thumbi Ndung'u
- University of KwaZulu-Natal, Durban, South Africa
- Africa Health Research Institute, Durban, South Africa
- Max Planck Institute for Infection Biology, Berlin, Germany
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Zabrina L Brumme
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
| | - Mark A Brockman
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
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Douglas P, Ye R, Radhamani S, Cobban A, Jenkins NP, Bartlett E, Roveredo J, Kettenbach AN, Lees-Miller SP. Nocodazole-Induced Expression and Phosphorylation of Anillin and Other Mitotic Proteins Are Decreased in DNA-Dependent Protein Kinase Catalytic Subunit-Deficient Cells and Rescued by Inhibition of the Anaphase-Promoting Complex/Cyclosome with proTAME but Not Apcin. Mol Cell Biol 2020; 40:e00191-19. [PMID: 32284347 PMCID: PMC7296215 DOI: 10.1128/mcb.00191-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/15/2019] [Accepted: 03/31/2020] [Indexed: 11/23/2022] Open
Abstract
The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) has well-established roles in DNA double-strand break repair, and recently, nonrepair functions have also been reported. To better understand its cellular functions, we deleted DNA-PKcs from HeLa and A549 cells using CRISPR/Cas9. The resulting cells were radiation sensitive, had reduced expression of ataxia-telangiectasia mutated (ATM), and exhibited multiple mitotic defects. Mechanistically, nocodazole-induced upregulation of cyclin B1, anillin, and securin was decreased in DNA-PKcs-deficient cells, as were phosphorylation of Aurora A on threonine 288, phosphorylation of Polo-like kinase 1 (PLK1) on threonine 210, and phosphorylation of targeting protein for Xenopus Klp2 (TPX2) on serine 121. Moreover, reduced nocodazole-induced expression of anillin, securin, and cyclin B1 and phosphorylation of PLK1, Aurora A, and TPX2 were rescued by inhibition of the anaphase-promoting complex/cyclosome (APC/C) by proTAME, which prevents binding of the APC/C-activating proteins Cdc20 and Cdh1 to the APC/C. Altogether, our studies suggest that loss of DNA-PKcs prevents inactivation of the APC/C in nocodazole-treated cells.
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Affiliation(s)
- Pauline Douglas
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ruiqiong Ye
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Suraj Radhamani
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Alexander Cobban
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nicole P Jenkins
- Norris Cotton Cancer Center, Geisel School of Medicine, Lebanon Campus at Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Edward Bartlett
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jonathan Roveredo
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Arminja N Kettenbach
- Norris Cotton Cancer Center, Geisel School of Medicine, Lebanon Campus at Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Susan P Lees-Miller
- Department of Biochemistry and Molecular Biology and Robson DNA Science Centre, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Prévost J, Tolbert WD, Medjahed H, Sherburn RT, Madani N, Zoubchenok D, Gendron-Lepage G, Gaffney AE, Grenier MC, Kirk S, Vergara N, Han C, Mann BT, Chénine AL, Ahmed A, Chaiken I, Kirchhoff F, Hahn BH, Haim H, Abrams CF, Smith AB, Sodroski J, Pazgier M, Finzi A. The HIV-1 Env gp120 Inner Domain Shapes the Phe43 Cavity and the CD4 Binding Site. mBio 2020; 11:e00280-20. [PMID: 32457241 PMCID: PMC7251204 DOI: 10.1128/mbio.00280-20] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/24/2020] [Indexed: 12/22/2022] Open
Abstract
The HIV-1 envelope glycoproteins (Env) undergo conformational changes upon interaction of the gp120 exterior glycoprotein with the CD4 receptor. The gp120 inner domain topological layers facilitate the transition of Env to the CD4-bound conformation. CD4 engages gp120 by introducing its phenylalanine 43 (Phe43) in a cavity ("the Phe43 cavity") located at the interface between the inner and outer gp120 domains. Small CD4-mimetic compounds (CD4mc) can bind within the Phe43 cavity and trigger conformational changes similar to those induced by CD4. Crystal structures of CD4mc in complex with a modified CRF01_AE gp120 core revealed the importance of these gp120 inner domain layers in stabilizing the Phe43 cavity and shaping the CD4 binding site. Our studies reveal a complex interplay between the gp120 inner domain and the Phe43 cavity and generate useful information for the development of more-potent CD4mc.IMPORTANCE The Phe43 cavity of HIV-1 envelope glycoproteins (Env) is an attractive druggable target. New promising compounds, including small CD4 mimetics (CD4mc), were shown to insert deeply into this cavity. Here, we identify a new network of residues that helps to shape this highly conserved CD4 binding pocket and characterize the structural determinants responsible for Env sensitivity to small CD4 mimetics.
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Affiliation(s)
- Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - William D Tolbert
- Infectious Diseases Division, Department of Medicine of Uniformed Services, University of the Health Sciences, Bethesda, Maryland, USA
| | | | - Rebekah T Sherburn
- Infectious Diseases Division, Department of Medicine of Uniformed Services, University of the Health Sciences, Bethesda, Maryland, USA
| | - Navid Madani
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Daria Zoubchenok
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | - Althea E Gaffney
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Melissa C Grenier
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sharon Kirk
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Natasha Vergara
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Changze Han
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Brendan T Mann
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of the Military Medicine, Bethesda, Maryland, USA
| | - Agnès L Chénine
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of the Military Medicine, Bethesda, Maryland, USA
| | - Adel Ahmed
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Irwin Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Beatrice H Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hillel Haim
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Cameron F Abrams
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine of Uniformed Services, University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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Déjean G, Tamura K, Cabrera A, Jain N, Pudlo NA, Pereira G, Viborg AH, Van Petegem F, Martens EC, Brumer H. Synergy between Cell Surface Glycosidases and Glycan-Binding Proteins Dictates the Utilization of Specific Beta(1,3)-Glucans by Human Gut Bacteroides. mBio 2020; 11:e00095-20. [PMID: 32265336 PMCID: PMC7157763 DOI: 10.1128/mbio.00095-20] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/09/2020] [Indexed: 01/06/2023] Open
Abstract
The human gut microbiota (HGM) has far-reaching impacts on human health and nutrition, which are fueled primarily by the metabolism of otherwise indigestible complex carbohydrates commonly known as dietary fiber. However, the molecular basis of the ability of individual taxa of the HGM to address specific dietary glycan structures remains largely unclear. In particular, the utilization of β(1,3)-glucans, which are widespread in the human diet as yeast, seaweed, and plant cell walls, had not previously been resolved. Through a systems-based approach, here we show that the symbiont Bacteroides uniformis deploys a single, exemplar polysaccharide utilization locus (PUL) to access yeast β(1,3)-glucan, brown seaweed β(1,3)-glucan (laminarin), and cereal mixed-linkage β(1,3)/β(1,4)-glucan. Combined biochemical, enzymatic, and structural analysis of PUL-encoded glycoside hydrolases (GHs) and surface glycan-binding proteins (SGBPs) illuminates a concerted molecular system by which B. uniformis recognizes and saccharifies these distinct β-glucans. Strikingly, the functional characterization of homologous β(1,3)-glucan utilization loci (1,3GUL) in other Bacteroides further demonstrated that the ability of individual taxa to utilize β(1,3)-glucan variants and/or β(1,3)/β(1,4)-glucans arises combinatorially from the individual specificities of SGBPs and GHs at the cell surface, which feed corresponding signals to periplasmic hybrid two-component sensors (HTCSs) via TonB-dependent transporters (TBDTs). These data reveal the importance of cooperativity in the adaptive evolution of GH and SGBP cohorts to address individual polysaccharide structures. We anticipate that this fine-grained knowledge of PUL function will inform metabolic network analysis and proactive manipulation of the HGM. Indeed, a survey of 2,441 public human metagenomes revealed the international, yet individual-specific, distribution of each 1,3GUL.IMPORTANCEBacteroidetes are a dominant phylum of the human gut microbiota (HGM) that target otherwise indigestible dietary fiber with an arsenal of polysaccharide utilization loci (PULs), each of which is dedicated to the utilization of a specific complex carbohydrate. Here, we provide novel insight into this paradigm through functional characterization of homologous PULs from three autochthonous Bacteroides species, which target the family of dietary β(1,3)-glucans. Through detailed biochemical and protein structural analysis, we observed an unexpected diversity in the substrate specificity of PUL glycosidases and glycan-binding proteins with regard to β(1,3)-glucan linkage and branching patterns. In combination, these individual enzyme and protein specificities support taxon-specific growth on individual β(1,3)-glucans. This detailed metabolic insight, together with a comprehensive survey of individual 1,3GULs across human populations, further expands the fundamental roadmap of the HGM, with potential application to the future development of microbial intervention therapies.
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Affiliation(s)
- Guillaume Déjean
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kazune Tamura
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Adriana Cabrera
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Namrata Jain
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nicholas A Pudlo
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Gabriel Pereira
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alexander Holm Viborg
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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40
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Prévost J, Edgar CR, Richard J, Trothen SM, Jacob RA, Mumby MJ, Pickering S, Dubé M, Kaufmann DE, Kirchhoff F, Neil SJD, Finzi A, Dikeakos JD. HIV-1 Vpu Downregulates Tim-3 from the Surface of Infected CD4 + T Cells. J Virol 2020; 94:e01999-19. [PMID: 31941771 PMCID: PMC7081912 DOI: 10.1128/jvi.01999-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 01/12/2020] [Indexed: 01/26/2023] Open
Abstract
Along with other immune checkpoints, T cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) is expressed on exhausted CD4+ and CD8+ T cells and is upregulated on the surface of these cells upon infection by human immunodeficiency virus type 1 (HIV-1). Recent reports have suggested an antiviral role for Tim-3. However, the molecular determinants of HIV-1 which modulate cell surface Tim-3 levels have yet to be determined. Here, we demonstrate that HIV-1 Vpu downregulates Tim-3 from the surface of infected primary CD4+ T cells, thus attenuating HIV-1-induced upregulation of Tim-3. We also provide evidence that the transmembrane domain of Vpu is required for Tim-3 downregulation. Using immunofluorescence microscopy, we determined that Vpu is in close proximity to Tim-3 and alters its subcellular localization by directing it to Rab 5-positive (Rab 5+) vesicles and targeting it for sequestration within the trans- Golgi network (TGN). Intriguingly, Tim-3 knockdown and Tim-3 blockade increased HIV-1 replication in primary CD4+ T cells, thereby suggesting that Tim-3 expression might represent a natural immune mechanism limiting viral spread.IMPORTANCE HIV infection modulates the surface expression of Tim-3, but the molecular determinants remain poorly understood. Here, we show that HIV-1 Vpu downregulates Tim-3 from the surface of infected primary CD4+ T cells through its transmembrane domain and alters its subcellular localization. Tim-3 blockade increases HIV-1 replication, suggesting a potential negative role of this protein in viral spread that is counteracted by Vpu.
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Affiliation(s)
- Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Cassandra R Edgar
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Steven M Trothen
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Rajesh Abraham Jacob
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Mitchell J Mumby
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Suzanne Pickering
- Department of Infectious Disease, King's College London School of Life Sciences and Medicine, Guy's Hospital, London, United Kingdom
| | - Mathieu Dubé
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
| | - Daniel E Kaufmann
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Stuart J D Neil
- Department of Infectious Disease, King's College London School of Life Sciences and Medicine, Guy's Hospital, London, United Kingdom
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Jimmy D Dikeakos
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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41
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Ding S, Grenier MC, Tolbert WD, Vézina D, Sherburn R, Richard J, Prévost J, Chapleau JP, Gendron-Lepage G, Medjahed H, Abrams C, Sodroski J, Pazgier M, Smith AB, Finzi A. A New Family of Small-Molecule CD4-Mimetic Compounds Contacts Highly Conserved Aspartic Acid 368 of HIV-1 gp120 and Mediates Antibody-Dependent Cellular Cytotoxicity. J Virol 2019; 93:e01325-19. [PMID: 31554684 PMCID: PMC6880173 DOI: 10.1128/jvi.01325-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) trimer mediates virus entry into cells. The "closed" conformation of Env is resistant to nonneutralizing antibodies (nnAbs). These antibodies mostly recognize occluded epitopes that can be exposed upon binding of CD4 or small-molecule CD4 mimetics (CD4mc). Here, we describe a new family of small molecules that expose Env to nnAbs and sensitize infected cells to antibody-dependent cellular cytotoxicity (ADCC). These compounds have a limited capacity to inhibit virus infection directly but are able to sensitize viral particles to neutralization by otherwise nonneutralizing antibodies. Structural analysis shows that some analogs of this family of CD4mc engage the gp120 Phe43 cavity by contacting the highly conserved D368 residue, making them attractive scaffolds for drug development.IMPORTANCE HIV-1 has evolved multiple strategies to avoid humoral responses. One efficient mechanism is to keep its envelope glycoprotein (Env) in its "closed" conformation. Here, we report on a new family of small molecules that are able to "open up" Env, thus exposing vulnerable epitopes. This new family of molecules binds in the Phe43 cavity and contacts the highly conserved D368 residue. The structural and biological attributes of molecules of this family make them good candidates for drug development.
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Affiliation(s)
- Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Melissa C Grenier
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - William D Tolbert
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Dani Vézina
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Rebekah Sherburn
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Jean-Philippe Chapleau
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | | | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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42
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Ding H, Grüll MP, Mulligan ME, Lang AS, Beatty JT. Induction of Rhodobacter capsulatus Gene Transfer Agent Gene Expression Is a Bistable Stochastic Process Repressed by an Extracellular Calcium-Binding RTX Protein Homologue. J Bacteriol 2019; 201:e00430-19. [PMID: 31501287 PMCID: PMC6832060 DOI: 10.1128/jb.00430-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 09/06/2019] [Indexed: 01/28/2023] Open
Abstract
Bacteriophage-like gene transfer agents (GTAs) have been discovered in both of the prokaryotic branches of the three-domain phylogenetic tree of life. The production of a GTA (RcGTA) by the phototrophic alphaproteobacterium Rhodobacter capsulatus is regulated by quorum sensing and a phosphorelay homologous to systems in other species that control essential functions such as the initiation of chromosome replication and cell division. In wild-type strains, RcGTA is produced in <3% of cells in laboratory cultures. Mutants of R. capsulatus that exhibit greatly elevated production of RcGTA were created decades ago by chemical mutagenesis, but the nature and molecular consequences of the mutation were unknown. We show that the number of cells in a population that go on to express RcGTA genes is controlled by a stochastic process, in contrast to a genetic process. We used transposon mutagenesis along with a fluorescent protein reporter system and genome sequence data to identify a gene, rcc00280, that encodes an RTX family calcium-binding protein homologue. The Rc280 protein acts as an extracellular repressor of RcGTA gene expression by decreasing the percentage of cells that induce the production of RcGTA.IMPORTANCE GTAs catalyze horizontal gene transfer (HGT), which is important for genomic evolution because the majority of genes found in bacterial genomes have undergone HGT at some point in their evolution. Therefore, it is important to determine how the production of GTAs is regulated to understand the factors that modulate the frequency of gene transfer and thereby specify the tempo of evolution. This work describes a new type of genetic regulation in which an extracellular calcium-binding protein homologue represses the induction of the Rhodobacter capsulatus GTA, RcGTA.
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Affiliation(s)
- Hao Ding
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marc P Grüll
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Martin E Mulligan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Andrew S Lang
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - J Thomas Beatty
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
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43
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Salamun SG, Sitz J, De La Cruz-Herrera CF, Yockteng-Melgar J, Marcon E, Greenblatt J, Fradet-Turcotte A, Frappier L. The Epstein-Barr Virus BMRF1 Protein Activates Transcription and Inhibits the DNA Damage Response by Binding NuRD. J Virol 2019; 93:e01070-19. [PMID: 31462557 PMCID: PMC6819917 DOI: 10.1128/jvi.01070-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/16/2019] [Indexed: 02/08/2023] Open
Abstract
The BMRF1 protein of Epstein-Barr virus (EBV) has multiple roles in viral lytic infection, including serving as the DNA polymerase processivity factor, activating transcription from several EBV promoters and inhibiting the host DNA damage response to double-stranded DNA breaks (DSBs). Using affinity purification coupled to mass spectrometry, we identified the nucleosome remodeling and deacetylation (NuRD) complex as the top interactor of BMRF1. We further found that NuRD components localize with BMRF1 at viral replication compartments and that this interaction occurs through the BMRF1 C-terminal region previously shown to mediate transcriptional activation. We identified an RBBP4 binding motif within this region that can interact with both RBBP4 and MTA2 components of the NuRD complex and showed that point mutation of this motif abrogates NuRD binding as well as the ability of BMRF1 to activate transcription from the BDLF3 and BLLF1 EBV promoters. In addition to its role in transcriptional regulation, NuRD has been shown to contribute to DSB signaling in enabling recruitment of RNF168 ubiquitin ligase and subsequent ubiquitylation at the break. We showed that BMRF1 inhibited RNF168 recruitment and ubiquitylation at DSBs and that this inhibition was at least partly relieved by loss of the NuRD interaction. The results reveal a mechanism by which BMRF1 activates transcription and inhibits DSB signaling and a novel role for NuRD in transcriptional activation in EBV.IMPORTANCE The Epstein-Barr virus (EBV) BMRF1 protein is critical for EBV infection, playing key roles in viral genome replication, activation of EBV genes, and inhibition of host DNA damage responses (DDRs). Here we show that BMRF1 targets the cellular nucleosome remodeling and deacetylation (NuRD) complex, using a motif in the BMRF1 transcriptional activation sequence. Mutation of this motif disrupts the ability of BMRF1 to activate transcription and interfere with DDRs, showing the importance of the NuRD interaction for BMRF1 functions. BMRF1 was shown to act at the same step in the DDR as NuRD, suggesting that it interferes with NuRD function.
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Affiliation(s)
- Samuel G Salamun
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Justine Sitz
- Cancer Research Center and CHU de Québec Research Center-Hôtel-Dieu de Québec, Université Laval, Québec, Canada
| | | | - Jaime Yockteng-Melgar
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Facultad de ciencias de la vida, Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador
| | - Edyta Marcon
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Jack Greenblatt
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Amelie Fradet-Turcotte
- Cancer Research Center and CHU de Québec Research Center-Hôtel-Dieu de Québec, Université Laval, Québec, Canada
| | - Lori Frappier
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
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44
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Ding S, Gasser R, Gendron-Lepage G, Medjahed H, Tolbert WD, Sodroski J, Pazgier M, Finzi A. CD4 Incorporation into HIV-1 Viral Particles Exposes Envelope Epitopes Recognized by CD4-Induced Antibodies. J Virol 2019; 93:e01403-19. [PMID: 31484748 PMCID: PMC6819941 DOI: 10.1128/jvi.01403-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 08/29/2019] [Indexed: 12/23/2022] Open
Abstract
CD4 downregulation on infected cells is a highly conserved function of primate lentiviruses. It has been shown to positively impact viral replication by a variety of mechanisms, including enhanced viral release and infectivity, decrease of cell reinfection, and protection from antibody-dependent cellular cytotoxicity (ADCC), which is often mediated by antibodies that require CD4 to change envelope (Env) conformation. Here, we report that incorporation of CD4 into HIV-1 viral particles affects Env conformation resulting in the exposure of occluded epitopes recognized by CD4-induced antibodies. This translates into enhanced neutralization susceptibility by these otherwise nonneutralizing antibodies but is prevented by the HIV-1 Nef accessory protein. Altogether, these findings suggest that another functional consequence of Nef-mediated CD4 downregulation is the protection of viral particles from neutralization by commonly elicited CD4-induced antibodies.IMPORTANCE It has been well established that Env-CD4 complexes expose epitopes recognized by commonly elicited CD4-induced antibodies at the surface of HIV-1-infected cells, rendering them vulnerable to ADCC responses. Here, we show that CD4 incorporation has a profound impact on Env conformation at the surface of viral particles. Incorporated CD4 exposes CD4-induced epitopes on Env, rendering HIV-1 susceptible to neutralization by otherwise nonneutralizing antibodies.
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Affiliation(s)
- Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Romain Gasser
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | | | - William D Tolbert
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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45
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Bhattacharya A, Sharma M, Pakkinathan C, Rosen BP, Leprohon P, Ouellette M. Genomewide Analysis of Mode of Action of the S-Adenosylmethionine Analogue Sinefungin in Leishmania infantum. mSystems 2019; 4:e00416-19. [PMID: 31615876 PMCID: PMC6794121 DOI: 10.1128/msystems.00416-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/30/2019] [Indexed: 11/20/2022] Open
Abstract
To further our understanding of one-carbon metabolism in the protozoan parasite Leishmania, we conducted genomic screens to study how the parasite responded to sinefungin (SNF) selection. SNF is a structural analogue of S-adenosylmethionine (AdoMet), a key methyl group donor to a number of biomolecules. One screen consisted of sequencing SNF-resistant mutants generated by stepwise selection with gradually increasing drug concentrations. These studies demonstrated deletion of the AdoMet transporter (AdoMetT1) by intergenic recombination as a crucial loss-of-function marker for SNF resistance. The second screen consisted of Cos-seq, a gain-of-function cosmid-based genomewide functional screen with increasing SNF concentration coupled to next-generation sequencing. Cosmids enriched in that screen and sequenced led to the identification of (i) the AdoMet synthetase (METK) as the major SNF target, (ii) an mRNA [(guanine-N7)-methyltransferase (CMT1)], (iii) a leucine carboxyl methyltransferase (LCMT), (iv) two tryparedoxin genes, and (v) two protein phosphatase regulatory genes. Further functional exploration indicated that LCMT interacts with one phosphatase catalytic subunit (PP2AC) and that mutation of the C-terminal leucine residue of PP2AC affects sinefungin susceptibility. These holistic screens led to the identification of transporters, biosynthetic genes, RNA and protein methyltransferases, as well as phosphatases linked to AdoMet-mediated functions in Leishmania IMPORTANCE The two main cellular metabolic one-carbon donors are reduced folates and S-adenosylmethionine, whose biosynthetic pathways have proven highly effective in chemotherapeutic interventions in various cell types. Sinefungin, a nucleoside analogue of S-adenosylmethionine, was shown to have potent activity against the protozoan parasite Leishmania Here, we studied resistance to sinefungin using whole-genome approaches as a way to further our understanding of the role of S-adenosylmethionine in this parasite and to reveal novel potential drug targets. These approaches allowed the characterization of novel features related to S-adenosylmethionine function in Leishmania which could further help in the development of sinefungin-like compounds against this pathogenic parasite.
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Affiliation(s)
- Arijit Bhattacharya
- Division of Infectious Disease and Immunity, CHU de Quebec Research Center, Quebec, Quebec, Canada
- Department of Microbiology, Infectious Disease and Immunology, University Laval, Quebec, Quebec, Canada
| | - Mansi Sharma
- Division of Infectious Disease and Immunity, CHU de Quebec Research Center, Quebec, Quebec, Canada
- Department of Microbiology, Infectious Disease and Immunology, University Laval, Quebec, Quebec, Canada
| | - Charles Pakkinathan
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA
| | - Philippe Leprohon
- Division of Infectious Disease and Immunity, CHU de Quebec Research Center, Quebec, Quebec, Canada
- Department of Microbiology, Infectious Disease and Immunology, University Laval, Quebec, Quebec, Canada
| | - Marc Ouellette
- Division of Infectious Disease and Immunity, CHU de Quebec Research Center, Quebec, Quebec, Canada
- Department of Microbiology, Infectious Disease and Immunology, University Laval, Quebec, Quebec, Canada
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46
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Déjean G, Tauzin AS, Bennett SW, Creagh AL, Brumer H. Adaptation of Syntenic Xyloglucan Utilization Loci of Human Gut Bacteroidetes to Polysaccharide Side Chain Diversity. Appl Environ Microbiol 2019; 85:e01491-19. [PMID: 31420336 PMCID: PMC6805095 DOI: 10.1128/aem.01491-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 08/08/2019] [Indexed: 12/16/2022] Open
Abstract
Genome sequencing has revealed substantial variation in the predicted abilities of individual species within animal gut microbiota to metabolize the complex carbohydrates comprising dietary fiber. At the same time, a currently limited body of functional studies precludes a richer understanding of how dietary glycan structures affect the gut microbiota composition and community dynamics. Here, using biochemical and biophysical techniques, we identified and characterized differences among recombinant proteins from syntenic xyloglucan utilization loci (XyGUL) of three Bacteroides and one Dysgonomonas species from the human gut, which drive substrate specificity and access to distinct polysaccharide side chains. Enzymology of four syntenic glycoside hydrolase family 5 subfamily 4 (GH5_4) endo-xyloglucanases revealed surprising differences in xyloglucan (XyG) backbone cleavage specificity, including the ability of some homologs to hydrolyze congested branched positions. Further, differences in the complement of GH43 alpha-l-arabinofuranosidases and GH95 alpha-l-fucosidases among syntenic XyGUL confer distinct abilities to fully saccharify plant species-specific arabinogalactoxyloglucan and/or fucogalactoxyloglucan. Finally, characterization of highly sequence-divergent cell surface glycan-binding proteins (SGBPs) across syntenic XyGUL revealed a novel group of XyG oligosaccharide-specific SGBPs encoded within select BacteroidesIMPORTANCE The catabolism of complex carbohydrates that otherwise escape the endogenous digestive enzymes of humans and other animals drives the composition and function of the gut microbiota. Thus, detailed molecular characterization of dietary glycan utilization systems is essential both to understand the ecology of these complex communities and to manipulate their compositions, e.g., to benefit human health. Our research reveals new insight into how ubiquitous members of the human gut microbiota have evolved a set of microheterogeneous gene clusters to efficiently respond to the structural variations of plant xyloglucans. The data here will enable refined functional prediction of xyloglucan utilization among diverse environmental taxa in animal guts and beyond.
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Affiliation(s)
- Guillaume Déjean
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alexandra S Tauzin
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stuart W Bennett
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Louise Creagh
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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47
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Drabovich AP, Saraon P, Drabovich M, Karakosta TD, Dimitromanolakis A, Hyndman ME, Jarvi K, Diamandis EP. Multi-omics Biomarker Pipeline Reveals Elevated Levels of Protein-glutamine Gamma-glutamyltransferase 4 in Seminal Plasma of Prostate Cancer Patients. Mol Cell Proteomics 2019; 18:1807-1823. [PMID: 31249104 PMCID: PMC6731075 DOI: 10.1074/mcp.ra119.001612] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Indexed: 11/06/2022] Open
Abstract
Seminal plasma, because of its proximity to prostate, is a promising fluid for biomarker discovery and noninvasive diagnostics. In this study, we investigated if seminal plasma proteins could increase diagnostic specificity of detecting primary prostate cancer and discriminate between high- and low-grade cancers. To select 147 most promising biomarker candidates, we combined proteins identified through five independent experimental or data mining approaches: tissue transcriptomics, seminal plasma proteomics, cell line secretomics, tissue specificity, and androgen regulation. A rigorous biomarker development pipeline based on selected reaction monitoring assays was designed to evaluate the most promising candidates. As a result, we qualified 76, and verified 19 proteins in seminal plasma of 67 negative biopsy and 152 prostate cancer patients. Verification revealed a prostate-specific, secreted and androgen-regulated protein-glutamine gamma-glutamyltransferase 4 (TGM4), which predicted prostate cancer on biopsy and outperformed age and serum Prostate-Specific Antigen (PSA). A machine-learning approach for data analysis provided improved multi-marker combinations for diagnosis and prognosis. In the independent verification set measured by an in-house immunoassay, TGM4 protein was upregulated 3.7-fold (p = 0.006) and revealed AUC = 0.66 for detecting prostate cancer on biopsy for patients with serum PSA ≥4 ng/ml and age ≥50. Very low levels of TGM4 (120 pg/ml) were detected in blood serum. Collectively, our study demonstrated rigorous evaluation of one of the remaining and not well-explored prostate-specific proteins within the medium-abundance proteome of seminal plasma. Performance of TGM4 warrants its further investigation within the distinct genomic subtypes and evaluation for the inclusion into emerging multi-biomarker panels.
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Affiliation(s)
- Andrei P Drabovich
- ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5T 3L9 Canada; §Department of Clinical Biochemistry, University Health Network, Toronto, Ontario, M5T 3L9 Canada; ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, M5T 3L9 Canada.
| | - Punit Saraon
- ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5T 3L9 Canada
| | | | - Theano D Karakosta
- §Department of Clinical Biochemistry, University Health Network, Toronto, Ontario, M5T 3L9 Canada
| | | | - M Eric Hyndman
- **Department of Surgery, Division of Urology, Southern Alberta Institute of Urology, University of Calgary, Calgary, AB T2V 1P9, Canada
| | - Keith Jarvi
- ‡‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5T 3L9 Canada; §§Department of Surgery, Division of Urology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, M5T 3L9 Canada.
| | - Eleftherios P Diamandis
- ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5T 3L9 Canada; §Department of Clinical Biochemistry, University Health Network, Toronto, Ontario, M5T 3L9 Canada; ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, M5T 3L9 Canada; ‡‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5T 3L9 Canada.
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Von Dwingelo J, Chung IYW, Price CT, Li L, Jones S, Cygler M, Abu Kwaik Y. Interaction of the Ankyrin H Core Effector of Legionella with the Host LARP7 Component of the 7SK snRNP Complex. mBio 2019; 10:e01942-19. [PMID: 31455655 PMCID: PMC6712400 DOI: 10.1128/mbio.01942-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/18/2022] Open
Abstract
Species of the Legionella genus encode at least 18,000 effector proteins that are translocated through the Dot/Icm type IVB translocation system into macrophages and protist hosts to enable intracellular growth. Eight effectors, including ankyrin H (AnkH), are common to all Legionella species. The AnkH effector is also present in Coxiella and Rickettsiella To date, no pathogenic effectors have ever been described that directly interfere with host cell transcription. We determined that the host nuclear protein La-related protein 7 (LARP7), which is a component of the 7SK small nuclear ribonucleoprotein (snRNP) complex, interacts with AnkH in the host cell nucleus. The AnkH-LARP7 interaction partially impedes interactions of the 7SK snRNP components with LARP7, interfering with transcriptional elongation by polymerase (Pol) II. Consistent with that, our data show AnkH-dependent global reprogramming of transcription of macrophages infected by Legionella pneumophila The crystal structure of AnkH shows that it contains four N-terminal ankyrin repeats, followed by a cysteine protease-like domain and an α-helical C-terminal domain. A substitution within the β-hairpin loop of the third ankyrin repeat results in diminishment of LARP7-AnkH interactions and phenocopies the ankH null mutant defect in intracellular growth. LARP7 knockdown partially suppresses intracellular proliferation of wild-type (WT) bacteria and increases the severity of the defect of the ΔankH mutant, indicating a role for LARP7 in permissiveness of host cells to intracellular bacterial infection. We conclude that the AnkH-LARP7 interaction impedes interaction of LARP7 with 7SK snRNP, which would block transcriptional elongation by Pol II, leading to host global transcriptional reprogramming and permissiveness to L. pneumophilaIMPORTANCE For intracellular pathogens to thrive in host cells, an environment that supports survival and replication needs to be established. L. pneumophila accomplishes this through the activity of the ∼330 effector proteins that are injected into host cells during infection. Effector functions range from hijacking host trafficking pathways to altering host cell machinery, resulting in altered cell biology and innate immunity. One such pathway is the host protein synthesis pathway. Five L. pneumophila effectors have been identified that alter host cell translation, and 2 effectors have been identified that indirectly affect host cell transcription. No pathogenic effectors have been described that directly interfere with host cell transcription. Here we show a direct interaction of the AnkH effector with a host cell transcription complex involved in transcriptional elongation. We identify a novel process by which AnkH interferes with host transcriptional elongation through interference with formation of a functional complex and show that this interference is required for pathogen proliferation.
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Affiliation(s)
- Juanita Von Dwingelo
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Ivy Yeuk Wah Chung
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Christopher T Price
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Lei Li
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Snake Jones
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
- Center for Predictive Medicine, College of Medicine, University of Louisville, Louisville, Kentucky, USA
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Tharmapalan P, Mahendralingam M, Berman HK, Khokha R. Mammary stem cells and progenitors: targeting the roots of breast cancer for prevention. EMBO J 2019; 38:e100852. [PMID: 31267556 PMCID: PMC6627238 DOI: 10.15252/embj.2018100852] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/11/2019] [Accepted: 04/11/2019] [Indexed: 12/24/2022] Open
Abstract
Breast cancer prevention is daunting, yet not an unsurmountable goal. Mammary stem and progenitors have been proposed as the cells-of-origin in breast cancer. Here, we present the concept of limiting these breast cancer precursors as a risk reduction approach in high-risk women. A wealth of information now exists for phenotypic and functional characterization of mammary stem and progenitor cells in mouse and human. Recent work has also revealed the hormonal regulation of stem/progenitor dynamics as well as intrinsic lineage distinctions between mammary epithelial populations. Leveraging these insights, molecular marker-guided chemoprevention is an achievable reality.
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Affiliation(s)
| | - Mathepan Mahendralingam
- Princess Margaret Cancer CentreUniversity Health NetworkUniversity of TorontoTorontoONCanada
| | - Hal K Berman
- Princess Margaret Cancer CentreUniversity Health NetworkUniversity of TorontoTorontoONCanada
| | - Rama Khokha
- Princess Margaret Cancer CentreUniversity Health NetworkUniversity of TorontoTorontoONCanada
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50
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Sharkey K, Beernink PT, Langley JM, Gantt S, Quach C, Dold C, Liu Q, Galvan M, Granoff DM. Anti-Factor H Antibody Reactivity in Young Adults Vaccinated with a Meningococcal Serogroup B Vaccine Containing Factor H Binding Protein. mSphere 2019; 4:e00393-19. [PMID: 31270173 PMCID: PMC6609231 DOI: 10.1128/msphere.00393-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 06/18/2019] [Indexed: 12/29/2022] Open
Abstract
Meningococcal serogroup B (MenB) vaccines contain recombinant factor H binding protein (FHbp), which can complex with complement factor H (CFH) and thereby risk eliciting anti-FH autoantibodies. While anti-FH antibodies can be present in sera of healthy persons, the antibodies are implicated in autoimmune atypical hemolytic uremic syndrome and C3 glomerulopathies. We immunized 120 students with a MenB vaccine (Bexsero). By enzyme-linked immunosorbent assay (ELISA), there were small increases in serum anti-FH levels at 3 weeks postvaccination (geometric mean optical density at 405 nm [OD405], 0.54 versus 0.51 preimmunization, P ≤ 0.003 for each schedule tested). There was a similar small increase in anti-FH antibody levels in a second historical MenB study of 20 adults with stored paired preimmunization and postimmunization sera (P = 0.007) but not in three other studies of 57 adults immunized with other meningococcal vaccines that did not contain recombinant FHbp (P = 0.17, 0.84, and 0.60, respectively). Thus, humans vaccinated with MenB-4C develop small increases in serum anti-FH antibody reactivity. Although not likely to be clinically important, the data indicate a host response to FH. In the prospective MenB study, three subjects (2.5%) developed higher anti-FH titers postimmunization. The elevated titers returned to baseline within 3 to 4 months, and none of the subjects reported adverse events during the follow-up. Although anti-FH antibodies can decrease FH function, the postimmunization sera with high anti-FH antibody levels did not impair serum FH function as measured using a hemolytic assay. Thus, while additional studies are warranted, there is no evidence that the anti-FH antibodies elicited by MenB-4C are likely to cause anti-FH-mediated autoimmune disorders. (This study has been registered at ClinicalTrials.gov under registration no. NCT02583412.)IMPORTANCE Meningococci are bacteria that cause sepsis and meningitis. Meningococcal species are subdivided into serogroups on the basis of different sugar capsules. Vaccines that target serogroup A, C, Y, and W capsules are safe and highly effective. New serogroup B (MenB) vaccines target a bacterial protein that can bind to a blood protein called complement factor H (FH). While serogroup B vaccines appear to be safe and effective, there is a theoretical risk that immunization with a bacterial protein that binds host FH might elicit anti-FH autoantibodies. Autoantibodies to FH have been detected in healthy persons but in rare cases can cause certain autoimmune diseases. We found small and/or transient increases in serum antibody to FH after MenB immunization. While no serious adverse events were reported in the subjects with elevated anti-FH titers, since onset of autoimmune disease is a rare event and may occur months or years after vaccination, additional, larger studies are warranted.
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Affiliation(s)
- Kelsey Sharkey
- Center for Immunobiology and Vaccine Development, University of California San Francisco Benioff Children's Hospital Oakland, Oakland, California, USA
| | - Peter T Beernink
- Center for Immunobiology and Vaccine Development, University of California San Francisco Benioff Children's Hospital Oakland, Oakland, California, USA
| | - Joanne M Langley
- IWK Health Centre and the Nova Scotia Health Authority, Canadian Center for Vaccinology at Dalhousie University, Halifax, Nova Scotia, Canada
| | - Soren Gantt
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Caroline Quach
- McGill University Health Centre Research Institute and CHU Sainte Justine, Montreal, Quebec, Canada
| | | | - Qin Liu
- Wistar Institute, Philadelphia, Pennsylvania, USA
| | - Manuel Galvan
- National Jewish Health Complement Laboratory, Denver, Colorado, USA
| | - Dan M Granoff
- Center for Immunobiology and Vaccine Development, University of California San Francisco Benioff Children's Hospital Oakland, Oakland, California, USA
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