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Khan R, Ji W, Guzman-Rivera J, Madhvi A, Andrews T, Richlin B, Suarez C, Gaur S, Cuddy W, Singh AR, Bukulmez H, Kaelber D, Kimura Y, Ganapathi U, Michailidis IE, Ukey R, Moroso-Fela S, Kuster JK, Casseus M, Roy J, Kleinman LC, Horton DB, Lakhani SA, Gennaro ML. A genetically modulated Toll-like-receptor-tolerant phenotype in peripheral blood cells of children with multisystem inflammatory syndrome. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.02.02.24301686. [PMID: 38370700 PMCID: PMC10871447 DOI: 10.1101/2024.02.02.24301686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Dysregulated innate immune responses contribute to multisystem inflammatory syndrome in children (MIS-C), characterized by gastrointestinal, mucocutaneous, and/or cardiovascular injury occurring weeks after SARS-CoV-2 exposure. To investigate innate immune functions in MIS-C, we stimulated ex vivo peripheral blood cells from MIS-C patients with agonists of Toll-like receptors (TLR), key innate immune response initiators. We found severely dampened cytokine responses and elevated gene expression of negative regulators of TLR signaling. Increased plasma levels of zonulin, a gut leakage marker, were also detected. These effects were also observed in children enrolled months after MIS-C recovery. Moreover, cells from MIS-C children carrying rare genetic variants of lysosomal trafficking regulator (LYST) were less refractory to TLR stimulation and exhibited lysosomal and mitochondrial abnormalities with altered energy metabolism. Our results strongly suggest that MIS-C hyperinflammation and/or excessive or prolonged stimulation with gut-originated TLR ligands drive immune cells to a lasting refractory state. TLR hyporesponsiveness is likely beneficial, as suggested by excess lymphopenia among rare LYST variant carriers. Our findings point to cellular mechanisms underlying TLR hyporesponsiveness; identify genetic determinants that may explain the MIS-C clinical spectrum; suggest potential associations between innate refractory states and long COVID; and highlight the need to monitor long-term consequences of MIS-C.
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Affiliation(s)
- Rehan Khan
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ
| | - Weizhen Ji
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510
| | - Jeisac Guzman-Rivera
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ
| | - Abhilasha Madhvi
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ
| | - Tracy Andrews
- Department of Biostatistics and Epidemiology, Rutgers School of Public Health, Piscataway, NJ
| | - Benjamin Richlin
- Pediatric Clinical Research Center, and Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
| | - Christian Suarez
- Pediatric Clinical Research Center, and Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
| | - Sunanda Gaur
- Department of Pediatrics, Clinical Research Center, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
| | | | - Aalok R Singh
- Maria Fareri Children's Hospital, Valhalla, NY
- New York Medical College, Valhalla, NY
| | - Hulya Bukulmez
- Department of Pediatrics, Division of Rheumatology, MetroHealth System, Cleveland OH
| | - David Kaelber
- Department of Pediatrics, Division of Rheumatology, MetroHealth System, Cleveland OH
- Center for Clinical Informatics Research and Education, MetroHealth System, Cleveland OH
- Department of Internal Medicine, Pediatrics, and Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland OH
| | - Yukiko Kimura
- Hackensack University Medical Center, Hackensack Meridian School of Medicine, Nutley, NJ
| | - Usha Ganapathi
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ
| | - Ioannis E Michailidis
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ
| | - Rahul Ukey
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ
| | - Sandra Moroso-Fela
- Department of Pediatrics, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
| | - John K Kuster
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510
| | - Myriam Casseus
- Department of Pediatrics, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
| | - Jason Roy
- Department of Biostatistics and Epidemiology, Rutgers School of Public Health, Piscataway, NJ
| | - Lawrence C Kleinman
- Department of Pediatrics, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
- Department of Global Urban Health, Rutgers School of Public Health, Piscataway, NJ
| | - Daniel B Horton
- Department of Biostatistics and Epidemiology, Rutgers School of Public Health, Piscataway, NJ
- Department of Pediatrics, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
- Rutgers Center for Pharmacoepidemiology and Treatment Science, Institute for Health, Health Care Policy and Aging Research, New Brunswick, NJ
| | - Saquib A Lakhani
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510
| | - Maria Laura Gennaro
- Public Health Research Institute, Rutgers New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ
- Department of Medicine, Rutgers New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ
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2
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Wang Q, Feng Z, He H, Hu X, Mao J, Chen X, Liu L, Wei X, Liu D, Bi S, Wang X, Ge B, Yu D, Huang F. Nonblinking carbon dots for imaging and tracking receptors on a live cell membrane. Chem Commun (Camb) 2021; 57:5554-5557. [PMID: 33969837 DOI: 10.1039/d1cc01120k] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Blinking occurs with nearly all fluorophores including organic dyes, fluorescent proteins, semiconductor quantum dots and carbon dots (CDs). We developed non-blinking and photoresistant fluorescent CDs by introducing multiple aromatic domains onto a single carbon dot and demonstrated their great potential for imaging and tracking of receptors on a live cell membrane.
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Affiliation(s)
- Qian Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580, China.
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Abstract
Understanding the cellular basis of human health and disease requires the spatial resolution of microscopy and the molecular-level details provided by spectroscopy. This review highlights imaging methods at the intersection of microscopy and spectroscopy with applications in cell biology. Imaging methods are divided into three broad categories: fluorescence microscopy, label-free approaches, and imaging tools that can be applied to multiple imaging modalities. Just as these imaging methods allow researchers to address new biological questions, progress in biological sciences will drive the development of new imaging methods. We highlight four topics in cell biology that illustrate the need for new imaging tools: nanoparticle-cell interactions, intracellular redox chemistry, neuroscience, and the increasing use of spheroids and organoids. Overall, our goal is to provide a brief overview of individual imaging methods and highlight recent advances in the use of microscopy for cell biology.
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Affiliation(s)
- Joshua D Morris
- School of Science and Technology, Georgia Gwinnett College, Lawrenceville, Georgia 30043, USA
| | - Christine K Payne
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA;
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Ferguson R, Subramanian V. The cellular uptake of angiogenin, an angiogenic and neurotrophic factor is through multiple pathways and largely dynamin independent. PLoS One 2018; 13:e0193302. [PMID: 29486010 PMCID: PMC5828446 DOI: 10.1371/journal.pone.0193302] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 02/08/2018] [Indexed: 01/25/2023] Open
Abstract
Angiogenin (ANG), a member of the RNase superfamily (also known as RNase 5) has neurotrophic, neuroprotective and angiogenic activities. Recently it has also been shown to be important in stem cell homeostasis. Mutations in ANG are associated with neurodegenerative diseases such as Amyotrophic Lateral Sclerosis (ALS) and Fronto-temporal dementia (FTD). ANG is a secreted protein which is taken up by cells and translocated to the nucleus. However, the import pathway/s through which ANG is taken up is/are still largely unclear. We have characterised the uptake of ANG in neuronal, astrocytic and microglial cell lines as well as primary neurons and astrocytes using pharmacological agents as well as dominant negative dynamin and Rab5 to perturb uptake and intracellular trafficking. We find that uptake of ANG is largely clathrin/dynamin independent and microtubule depolymerisation has a marginal effect. Perturbation of membrane ruffling and macropinocytosis significantly inhibited ANG uptake suggesting an uptake mechanism similar to RNase A. Our findings shed light on why mutations which do not overtly affect RNase activity but cause impaired localization are associated with neurodegenerative disease.
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Affiliation(s)
- Ross Ferguson
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Vasanta Subramanian
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- * E-mail:
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5
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Lasič E, Galland F, Vardjan N, Šribar J, Križaj I, Leite MC, Zorec R, Stenovec M. Time-dependent uptake and trafficking of vesicles capturing extracellular S100B in cultured rat astrocytes. J Neurochem 2016; 139:309-323. [PMID: 27488079 DOI: 10.1111/jnc.13754] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 07/21/2016] [Accepted: 07/26/2016] [Indexed: 01/16/2023]
Abstract
Astrocytes, the most heterogeneous glial cells in the central nervous system, contribute to brain homeostasis, by regulating a myriad of functions, including the clearance of extracellular debris. When cells are damaged, cytoplasmic proteins may exit into the extracellular space. One such protein is S100B, which may exert toxic effects on neighboring cells unless it is removed from the extracellular space, but the mechanisms of this clearance are poorly understood. By using time-lapse confocal microscopy and fluorescently labeled S100B (S100B-Alexa488 ) and fluorescent dextran (Dextran546 ), a fluid phase uptake marker, we examined the uptake of fluorescently labeled S100B-Alexa488 from extracellular space and monitored trafficking of vesicles that internalized S100B-Alexa488 . Initially, S100B-Alexa488 and Dextran546 internalized with distinct rates into different endocytotic vesicles; S100B-Alexa488 internalized into smaller vesicles than Dextran546 . At a later stage, S100B-Alexa488 -positive vesicles substantially co-localized with Dextran546 -positive endolysosomes and with acidic LysoTracker-positive vesicles. Cell treatment with anti-receptor for advanced glycation end products (RAGE) antibody, which binds to RAGE, a 'scavenger receptor', partially inhibited uptake of S100B-Alexa488 , but not of Dextran546 . The dynamin inhibitor dynole 34-2 inhibited internalization of both fluorescent probes. Directional mobility of S100B-Alexa488 -positive vesicles increased over time and was inhibited by ATP stimulation, an agent that increases cytosolic free calcium concentration ([Ca2+ ]i ). We conclude that astrocytes exhibit RAGE- and dynamin-dependent vesicular mechanism to efficiently remove S100B from the extracellular space. If a similar process occurs in vivo, astroglia may mitigate the toxic effects of extracellular S100B by this process under pathophysiologic conditions. This study reveals the vesicular clearance mechanism of extracellular S100B in astrocytes. Initially, fluorescent S100B internalizes into smaller endocytotic vesicles than dextran molecules. At a later stage, both probes co-localize within endolysosomes. S100B internalization is both dynamin- and RAGE-dependent, whereas dextran internalization is dependent on dynamin. Vesicle internalization likely mitigates the toxic effects of extracellular S100B and other waste products.
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Affiliation(s)
- Eva Lasič
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Fabiana Galland
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Nina Vardjan
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
| | - Jernej Šribar
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Marina Concli Leite
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Robert Zorec
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia. .,Celica Biomedical, Ljubljana, Slovenia.
| | - Matjaž Stenovec
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia. .,Celica Biomedical, Ljubljana, Slovenia.
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Intracellular dynamics and fate of polystyrene nanoparticles in A549 Lung epithelial cells monitored by image (cross-) correlation spectroscopy and single particle tracking. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2411-9. [PMID: 26164626 DOI: 10.1016/j.bbamcr.2015.07.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 06/19/2015] [Accepted: 07/07/2015] [Indexed: 11/20/2022]
Abstract
Novel insights in nanoparticle (NP) uptake routes of cells, their intracellular trafficking and subcellular targeting can be obtained through the investigation of their temporal and spatial behavior. In this work, we present the application of image (cross-) correlation spectroscopy (IC(C)S) and single particle tracking (SPT) to monitor the intracellular dynamics of polystyrene (PS) NPs in the human lung carcinoma A549 cell line. The ensemble kinetic behavior of NPs inside the cell was characterized by temporal and spatiotemporal image correlation spectroscopy (TICS and STICS). Moreover, a more direct interpretation of the diffusion and flow detected in the NP motion was obtained by SPT by monitoring individual NPs. Both techniques demonstrate that the PS NP transport in A549 cells is mainly dependent on microtubule-assisted transport. By applying spatiotemporal image cross-correlation spectroscopy (STICCS), the correlated motions of NPs with the early endosomes, late endosomes and lysosomes are identified. PS NPs were equally distributed among the endolysosomal compartment during the time interval of the experiments. The cotransport of the NPs with the lysosomes is significantly larger compared to the other cell organelles. In the present study we show that the complementarity of ICS-based techniques and SPT enables a consistent elaborate model of the complex behavior of NPs inside biological systems.
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Chaudhari K, Pradeep T. In vitro colocalization of plasmonic nano-biolabels and biomolecules using plasmonic and Raman scattering microspectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:046011. [PMID: 25901655 DOI: 10.1117/1.jbo.20.4.046011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/20/2015] [Indexed: 06/04/2023]
Abstract
An insight into the intracellular fate of theranostics is important for improving their potential in biological applications. In vivo efficacy of plasmonic theranostics depends on our ability to monitor temporal changes in their size, shape, and state of aggregation, and the identification of molecules adsorbed on their surfaces. We develop a technique which combines plasmonic and Raman scattering microspectroscopy to colocalize plasmonic scattering from metallic nanoparticles with the Raman signatures of biomolecules adsorbed on the surface of the former. Using this technique, we have colocalized biomolecules with the plasmonic scattering from silver nanoparticles in the vicinity of Escherichia coli bacteria. To prove the applicability of this setup for the measurements on mammalian cells, imaging of HEK293 cells treated with gold nanoparticles was performed. We discuss the importance of such correlated measurements over individual techniques, although the latter may lead to misinterpretation of results. Finally, with the above-mentioned examples, we have given criteria to improve the specificity of theranostics. We believe that this methodology will be considered as a prime development in the assessment of theranostics.
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Rab14 regulates maturation of macrophage phagosomes containing the fungal pathogen Candida albicans and outcome of the host-pathogen interaction. Infect Immun 2015; 83:1523-35. [PMID: 25644001 PMCID: PMC4363425 DOI: 10.1128/iai.02917-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Avoidance of innate immune defense is an important mechanism contributing to the pathogenicity of microorganisms. The fungal pathogen Candida albicans undergoes morphogenetic switching from the yeast to the filamentous hyphal form following phagocytosis by macrophages, facilitating its escape from the phagosome, which can result in host cell lysis. We show that the intracellular host trafficking GTPase Rab14 plays an important role in protecting macrophages from lysis mediated by C. albicans hyphae. Live-cell imaging of macrophages expressing green fluorescent protein (GFP)-tagged Rab14 or dominant negative Rab14, or with small interfering RNA (siRNA)-mediated knockdown of Rab14, revealed the temporal dynamics of this protein and its influence on the maturation of macrophage phagosomes following the engulfment of C. albicans cells. Phagosomes containing live C. albicans cells became transiently Rab14 positive within 2 min following engulfment. The duration of Rab14 retention on phagosomes was prolonged for hyphal cargo and was directly proportional to hyphal length. Interference with endogenous Rab14 did not affect the migration of macrophages toward C. albicans cells, the rate of engulfment, the overall uptake of fungal cells, or early phagosome processing. However, Rab14 depletion delayed the acquisition of the late phagosome maturation markers LAMP1 and lysosomal cathepsin, indicating delayed formation of a fully bioactive lysosome. This was associated with a significant increase in the level of macrophage killing by C. albicans. Therefore, Rab14 activity promotes phagosome maturation during C. albicans infection but is dysregulated on the phagosome in the presence of the invasive hyphal form, which favors fungal survival and escape.
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Abstract
Lysosomes are membrane-bound organelles responsible for the transport and degradation of intracellular and extracellular cargo. The intracellular motion of lysosomes is both diffusive and active, mediated by motor proteins moving lysosomes along microtubules. We sought to determine how lysosome diameter influences lysosome transport. We used osmotic swelling to double the diameter of lysosomes, creating a population of enlarged lysosomes. This allowed us to directly examine the intracellular transport of the same organelle as a function of diameter. Lysosome transport was measured using live cell fluorescence microscopy and single particle tracking. We find, as expected, the diffusive component of intracellular transport is decreased proportional to the increased lysosome diameter. Active transport of the enlarged lysosomes is not affected by the increased lysosome diameter.
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Shuang B, Chen J, Kisley L, Landes CF. Troika of single particle tracking programing: SNR enhancement, particle identification, and mapping. Phys Chem Chem Phys 2014; 16:624-34. [PMID: 24263676 PMCID: PMC4041580 DOI: 10.1039/c3cp53968g] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Single particle tracking (SPT) techniques provide a microscopic approach to probe in vivo and in vitro structure and reactions. Automatic analysis of SPT data with high efficiency and accuracy spurs the development of SPT algorithms. In this perspective, we review a range of available techniques used in SPT analysis programs. In addition, we present an example SPT program step-by-step to provide a guide so that researchers can use, modify, and/or write a SPT program for their own purposes.
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Affiliation(s)
- Bo Shuang
- Department of Chemistry, Rice University, Houston, Texas, United States. Tel: (1)713 348 4437
| | - Jixin Chen
- Department of Chemistry, Rice University, Houston, Texas, United States. Tel: (1)713 348 4437
| | - Lydia Kisley
- Department of Chemistry, Rice University, Houston, Texas, United States. Tel: (1)713 348 4437
| | - Christy F. Landes
- Department of Chemistry, Rice University, Houston, Texas, United States. Tel: (1)713 348 4437
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, United States. Tel: (1)713 348 4232
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Quantitative image analysis approaches for probing Rab GTPase localization and function in mammalian cells. Biochem Soc Trans 2013; 40:1389-93. [PMID: 23176486 DOI: 10.1042/bst20120145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Membrane traffic pathways play an essential role in cells, providing a mechanism for organelles of the endomembrane system to communicate and exchange material between each other. A significant number of infections and diseases are associated with trafficking pathways, and as such gaining a greater understanding of their regulation is essential. Fluorescence-based imaging techniques are widely used to probe the trafficking machinery within cells, and many of these methods have the potential to be applied in a quantitative manner. In the present mini-review, we highlight several recent examples of how image intensity, kinetic measurements, co-localization and texture feature analysis have been used to study the function of one key family of membrane traffic regulators, the Rab GTPases. We give specific emphasis to the importance of the quantitative nature of these recent studies and comment on their potential applicability to a high-throughput format.
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12
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Regulation of hepatitis B virus infection by Rab5, Rab7, and the endolysosomal compartment. J Virol 2013; 87:6415-27. [PMID: 23536683 DOI: 10.1128/jvi.00393-13] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Despite important progress toward deciphering human hepatitis B virus (HBV) entry into host cells, many aspects of the early steps of the life cycle remained completely obscure. Following endocytosis, HBV must travel through the complex network of the endocytic pathway to reach the cell nucleus and initiate replication. In addition to guiding the viral particles to the replication site, the endosomal vesicles may play a crucial role in infection, providing the appropriate environment for virus uncoating and nucleocapsid release. In this work, we investigated the trafficking of HBV particles internalized in permissive cells. Expression of key Rab proteins, involved in specific pathways leading to different intracellular locations, was modulated in HepaRG cells, using a stable and inducible short hairpin RNA (shRNA) expression system. The trafficking properties of the newly developed cells were demonstrated by confocal microscopy and flow cytometry using specific markers. The results showed that HBV infection strongly depends on Rab5 and Rab7 expression, indicating that HBV transport from early to mature endosomes is required for a step in the viral life cycle. This may involve reduction of disulfide bond-linked envelope proteins, as alteration of the redox potential of the endocytic pathway resulted in inhibition of infection. Subcellular fractionation of HBV-infected cells showed that viral particles are further transported to lysosomes. Intriguingly, infection was not dependent on the lysosomal activity, suggesting that trafficking to this compartment is a "dead-end" route. Together, these data add to our understanding of the HBV-host cell interactions controlling the early stages of infection.
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Humphries WH, Payne CK. Imaging lysosomal enzyme activity in live cells using self-quenched substrates. Anal Biochem 2012; 424:178-83. [PMID: 22387398 PMCID: PMC3327787 DOI: 10.1016/j.ab.2012.02.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 02/20/2012] [Accepted: 02/24/2012] [Indexed: 12/16/2022]
Abstract
Endocytosis, the internalization and transport of extracellular cargo, is an essential cellular process. The ultimate step in endocytosis is the intracellular degradation of extracellular cargo for use by the cell. While live cell imaging and single particle tracking have been well-utilized to study the internalization and transport of cargo, the final degradation step has required separate biochemical assays. We describe the use of self-quenched endocytic cargo to image the intracellular transport and degradation of endocytic cargo directly in live cells. We first outline the fluorescent labeling and quantification of two common endocytic cargos: a protein, bovine serum albumin, and a lipid nanoparticle, low-density lipoprotein. In vitro measurements confirm that self-quenching is a function of the number of fluorophores bound to the protein or particle and that recovery of the fluorescent signal occurs in response to enzymatic degradation. We then use confocal fluorescence microscopy and flow cytometry to demonstrate the use of self-quenched bovine serum albumin with standard fluorescence techniques. Using live cell imaging and single particle tracking, we find that the degradation of bovine serum albumin occurs in an endo-lysosomal vesicle that is positive for LAMP1.
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Affiliation(s)
- William. H. Humphries
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA
| | - Christine K. Payne
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA
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Vercauteren D, Deschout H, Remaut K, Engbersen JFJ, Jones AT, Demeester J, De Smedt SC, Braeckmans K. Dynamic colocalization microscopy to characterize intracellular trafficking of nanomedicines. ACS NANO 2011; 5:7874-84. [PMID: 21923168 DOI: 10.1021/nn2020858] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
To gain a better understanding of intracellular processing of nanomedicines, we employed quantitative live-cell fluorescence colocalization microscopy to study endosomal trafficking of polyplexes in retinal pigment epithelium cells. A new, dynamic colocalization algorithm was developed, based on particle tracking and trajectory correlation, allowing for spatiotemporal characterization of internalized polyplexes in comparison with endosomal compartments labeled with EGFP constructs. This revealed early trafficking of the polyplexes specifically to Rab5- and flotillin-2-positive vesicles and subsequent delivery to Rab7 and LAMP1-labeled late endolysosomes where the major fraction of the polyplexes remains entrapped for days, suggesting the functional loss of these nanomedicines. Colocalization of polyplexes with the autophagy marker LC3 suggests for the first time that the process of xenophagy could play an important role in the persistent endosomal entrapment of nanomedicines.
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Affiliation(s)
- Dries Vercauteren
- Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium
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15
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Humphries WH, Szymanski CJ, Payne CK. Endo-lysosomal vesicles positive for Rab7 and LAMP1 are terminal vesicles for the transport of dextran. PLoS One 2011; 6:e26626. [PMID: 22039519 PMCID: PMC3200357 DOI: 10.1371/journal.pone.0026626] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 09/29/2011] [Indexed: 12/30/2022] Open
Abstract
The endo-lysosomal pathway is essential for intracellular transport and the degradation of extracellular cargo. The relationship between three populations of endo-lysosomal vesicles--Rab7-positive, LAMP1-positive, and both Rab7- and LAMP1-postive--was probed with fluorescence microscopy and single particle tracking. Of specific interest was determining if these vesicles were intermediate or terminal vesicles in the transport of extracellular cargo. We find that the major organelle in the endo-lysosomal pathway, both in terms of population and cargo transport, is positive for Rab7 and LAMP1. Dextran, a fluid phase cargo, shifts from localization within all three populations of vesicles at 30 minutes and 1 hour to primarily LAMP1- and Rab7/LAMP1-vesicles at longer times. This demonstrates that LAMP1- and Rab7/LAMP1-vesicles are terminal vesicles in the endo-lysosomal pathway. We tested two possible mechanisms for this distribution of cargo, delivery to mannose 6-phosphate receptor (M6PR)-negative vesicles and the fusion dynamics of individual vesicles. We find no correlation with M6PR but do find that Rab7-vesicles undergo significantly fewer fusion events than LAMP1- or Rab7/LAMP1-vesicles suggesting that the distribution of fluid phase cargo is driven by vesicle dynamics.
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Affiliation(s)
- William H. Humphries
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Craig J. Szymanski
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Christine K. Payne
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States of America
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