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Mouat IC, Allanach JR, Fettig NM, Fan V, Girard AM, Shanina I, Osborne LC, Vorobeychik G, Horwitz MS. Gammaherpesvirus infection drives age-associated B cells toward pathogenicity in EAE and MS. Sci Adv 2022; 8:eade6844. [PMID: 36427301 PMCID: PMC9699667 DOI: 10.1126/sciadv.ade6844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
While age-associated B cells (ABCs) are known to expand and persist following viral infection and during autoimmunity, their interactions are yet to be studied together in these contexts. Here, we directly compared CD11c+T-bet+ ABCs using models of Epstein-Barr virus (EBV), gammaherpesvirus 68 (γHV68), multiple sclerosis (MS), and experimental autoimmune encephalomyelitis (EAE), and found that each drives the ABC population to opposing phenotypes. EBV infection has long been implicated in MS, and we have previously shown that latent γHV68 infection exacerbates EAE. Here, we demonstrate that ABCs are required for γHV68-enhanced disease. We then show that the circulating ABC population is expanded and phenotypically altered in people with relapsing MS. In this study, we show that viral infection and autoimmunity differentially affect the phenotype of ABCs in humans and mice, and we identify ABCs as functional mediators of viral-enhanced autoimmunity.
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Affiliation(s)
- Isobel C. Mouat
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessica R. Allanach
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Naomi M. Fettig
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vina Fan
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anna M. Girard
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Iryna Shanina
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lisa C. Osborne
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Galina Vorobeychik
- Fraser Health Multiple Sclerosis Clinic, Burnaby, British Columbia, Canada
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marc S. Horwitz
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- Corresponding author.
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2
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Fettig NM, Robinson HG, Allanach JR, Davis KM, Simister RL, Wang EJ, Sharon AJ, Ye J, Popple SJ, Seo JH, Gibson DL, Crowe SA, Horwitz MS, Osborne LC. Inhibition of Th1 activation and differentiation by dietary guar gum ameliorates experimental autoimmune encephalomyelitis. Cell Rep 2022; 40:111328. [PMID: 36103823 DOI: 10.1016/j.celrep.2022.111328] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [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: 11/30/2021] [Revised: 06/29/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022] Open
Abstract
Dietary fibers are potent modulators of immune responses that can restrain inflammation in multiple disease contexts. However, dietary fibers encompass a biochemically diverse family of carbohydrates, and it remains unknown how individual fiber sources influence immunity. In a direct comparison of four different high-fiber diets, we demonstrate a potent ability of guar gum to delay disease and neuroinflammation in experimental autoimmune encephalomyelitis, a T cell-mediated mouse model of multiple sclerosis. Guar gum-specific alterations to the microbiota are limited, and disease protection appears to be independent of fiber-induced increases in short-chain fatty acid levels or regulatory CD4+ T cells. Instead, CD4+ T cells of guar gum-supplemented mice are less encephalitogenic due to reduced activation, proliferation, Th1 differentiation, and altered migratory potential. These findings reveal specificity in the host response to fiber sources and define a pathway of fiber-induced immunomodulation that protects against pathologic neuroinflammation.
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Affiliation(s)
- Naomi M Fettig
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Hannah G Robinson
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jessica R Allanach
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Katherine M Davis
- Department of Botany, University of British Columba, Vancouver, BC V6T 1Z3, Canada
| | - Rachel L Simister
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Elsie J Wang
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Andrew J Sharon
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jiayu Ye
- Department of Biology, University of British Columbia-Okanagan, Kelowna, BC V1V 1V7, Canada
| | - Sarah J Popple
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jung Hee Seo
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Deanna L Gibson
- Department of Biology, University of British Columbia-Okanagan, Kelowna, BC V1V 1V7, Canada
| | - Sean A Crowe
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Marc S Horwitz
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Lisa C Osborne
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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Fettig NM, Robinson HG, Allanach JR, Simister RL, Wang EJ, Jiayu Y, Davis KM, Seo JH, Gibson DL, Crowe SA, Horwitz MS, Osborne LC. A dietary fiber limits autoimmune neuroinflammation by restricting Th1 activation, polarization, and migration. The Journal of Immunology 2022. [DOI: 10.4049/jimmunol.208.supp.60.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abstract
Dietary fibers and their breakdown products have been shown to limit inflammation in multiple disease contexts. However, the term “dietary fiber” encompasses a biochemically diverse family of carbohydrates, and it remains unknown how different fiber sources influence immune cell function. To address this question, we assessed the immunomodulatory capacity of different fiber types in a mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). C57BL/6 mice were fed a control diet (5% cellulose) or diets enriched (30%) with resistant starch, inulin, pectin, or guar gum for 2 weeks prior to EAE induction. A diet rich in guar gum uniquely ameliorated the clinical, pathological, and immunological features of EAE. Limited central nervous system (CNS) infiltration of IFNγ+CD4+ T cells (Th1s) in guar gum-fed mice could be attributed to T cell-intrinsic impairment Th1 activation and polarization. Nanostring nCounter transcriptional analyses revealed downregulation of migration-associated markers in CD4+ T cells isolated from guar gum/EAE mice, which was supported by reduced cell-surface expression of integrins involved in migration into the CNS. Functionally, this translated to limited migration of guar gum-derived encephalitogenic Th1s into the CNS upon adoptive transfer into control-fed recipients, which reduced incidence and severity of EAE. However, the 16S rRNA microbiome signature and short chain fatty acid profiles were not unique in comparison to other fiber-supplemented diets, indicating a novel mechanism of action from those previously ascribed in high fiber diet studies. These data confirm the individuality of dietary fibers and identify a novel immunomodulatory function of guar gum.
This project was supported by the endMS doctoral studentship program (Multiple Sclerosis Society of Canada) (NMF, JRA), the Canadian Institutes for Health Research (PJT-148909), and the Canada Research Chair program (LCO).
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Affiliation(s)
| | | | | | | | | | - Ye Jiayu
- 1Univ. of British Columbia, Canada
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Allanach JR, Farrell JW, Mésidor M, Karimi-Abdolrezaee S. Current status of neuroprotective and neuroregenerative strategies in multiple sclerosis: A systematic review. Mult Scler 2022; 28:29-48. [PMID: 33870797 PMCID: PMC8688986 DOI: 10.1177/13524585211008760] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [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: 03/13/2021] [Revised: 03/13/2021] [Accepted: 03/21/2021] [Indexed: 12/09/2022]
Abstract
BACKGROUND Immune-mediated demyelination and consequent degeneration of oligodendrocytes and axons are hallmark features of multiple sclerosis (MS). Remyelination declines in progressive MS, causing permanent axonal loss and irreversible disabilities. Strategies aimed at enhancing remyelination are critical to attenuate disease progression. OBJECTIVE We systematically reviewed recent advances in neuroprotective and regenerative therapies for MS, covering preclinical and clinical studies. METHODS We searched three biomedical databases using defined keywords. Two authors independently reviewed articles for inclusion based on pre-specified criteria. The data were extracted from each study and assessed for risk of bias. RESULTS Our search identified 7351 studies from 2014 to 2020, of which 221 met the defined criteria. These studies reported 262 interventions, wherein 92% were evaluated in animal models. These interventions comprised protein, RNA, lipid and cellular biologics, small molecules, inorganic compounds, and dietary and physiological interventions. Small molecules were the most highly represented strategy, followed by antibody therapies and stem cell transplantation. CONCLUSION While significant strides have been made to develop regenerative treatments for MS, the current evidence illustrates a skewed representation of the types of strategies that advance to clinical trials. Further examination is thus required to address current barriers to implementing experimental treatments in clinical settings.
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Affiliation(s)
- Jessica R Allanach
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada
| | - John W. Farrell
- Department of Health and Human Performance, Texas State University, San Marcos, TX, USA
| | - Miceline Mésidor
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada/Department of Social and Preventive Medicine, Université de Montréal, Montréal, QC, Canada
| | - Soheila Karimi-Abdolrezaee
- Department of Physiology and Pathophysiology, Regenerative Medicine Program, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada/Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
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Allanach JR, Hardman BK, Fettig NM, Mouat I, Gu Y, Jean-Baptiste V, Shanina I, Osborne LC, Vorobeychik G, Horwitz MS. Insights into the role of Epstein-Barr virus infection in multiple sclerosis using a novel humanized mouse model of disease. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.58.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system without a clear cause. Epstein-Barr virus (EBV) is proposed to contribute to the pathogenesis of MS through unknown mechanisms. Evidence for a role of EBV infection in MS comes from both epidemiological and experimental studies, however, due to its narrow host tropism, there are currently few suitable animal models of MS that incorporate EBV infection. Recent advancements in humanized mouse modelling has enabled direct infection for the study of EBV-associated malignancies. We therefore chose to evaluate the role of EBV infection in humanized mice with experimental autoimmune encephalomyelitis (EAE), a widely used model of MS. Immunocompromised mice were engrafted with peripheral blood mononuclear cells (PBMC) derived from individuals with relapsing MS (RRMS) or from matched healthy EBV seropositive or seronegative donors. We observed that HuPBMC mice induced with EAE developed ascending paralysis, weight loss and signs of discomfort consistent with classical EAE models. Further, HuPBMC EAE showed significant T cell infiltration of both the brain and spinal cord, notably of IFN gamma-expressing CD4 and CD8 T cells, resulting in spinal cord and cerebellar demyelination. HuPBMC EAE mice derived from EBV seropositive donors developed earlier disease onset with more severe clinical symptoms compared to EBV seronegative donor-derived mice. We also observed increase disease severity among mice derived from RRMS patients compared to healthy controls. With continued improvement and characterization of this novel humanized EAE model, additional environmental and genetic risk factors can be evaluated in a system with human immune-mediated pathology.
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Affiliation(s)
| | | | | | | | - Yu Gu
- 1University of British Columbia, Canada
| | | | | | | | - Galina Vorobeychik
- 1University of British Columbia, Canada
- 2Fraser Health Multiple Sclerosis Clinic, Canada
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Rojas OL, Pröbstel AK, Porfilio EA, Wang AA, Charabati M, Sun T, Lee DSW, Galicia G, Ramaglia V, Ward LA, Leung LYT, Najafi G, Khaleghi K, Garcillán B, Li A, Besla R, Naouar I, Cao EY, Chiaranunt P, Burrows K, Robinson HG, Allanach JR, Yam J, Luck H, Campbell DJ, Allman D, Brooks DG, Tomura M, Baumann R, Zamvil SS, Bar-Or A, Horwitz MS, Winer DA, Mortha A, Mackay F, Prat A, Osborne LC, Robbins C, Baranzini SE, Gommerman JL. Recirculating Intestinal IgA-Producing Cells Regulate Neuroinflammation via IL-10. Cell 2019; 176:610-624.e18. [PMID: 30612739 DOI: 10.1016/j.cell.2018.11.035] [Citation(s) in RCA: 190] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 09/28/2018] [Accepted: 11/21/2018] [Indexed: 01/29/2023]
Abstract
Plasma cells (PC) are found in the CNS of multiple sclerosis (MS) patients, yet their source and role in MS remains unclear. We find that some PC in the CNS of mice with experimental autoimmune encephalomyelitis (EAE) originate in the gut and produce immunoglobulin A (IgA). Moreover, we show that IgA+ PC are dramatically reduced in the gut during EAE, and likewise, a reduction in IgA-bound fecal bacteria is seen in MS patients during disease relapse. Removal of plasmablast (PB) plus PC resulted in exacerbated EAE that was normalized by the introduction of gut-derived IgA+ PC. Furthermore, mice with an over-abundance of IgA+ PB and/or PC were specifically resistant to the effector stage of EAE, and expression of interleukin (IL)-10 by PB plus PC was necessary and sufficient to confer resistance. Our data show that IgA+ PB and/or PC mobilized from the gut play an unexpected role in suppressing neuroinflammation.
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Affiliation(s)
- Olga L Rojas
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Anne-Katrin Pröbstel
- Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Elisa A Porfilio
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Angela A Wang
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Marc Charabati
- Neuroimmunology Unit, CRCHUM and Department of Neurosciences, Faculty of Medicine, Université de Montréal, QC H2X 0A9, Canada
| | - Tian Sun
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Dennis S W Lee
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Georgina Galicia
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Valeria Ramaglia
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Lesley A Ward
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Leslie Y T Leung
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ghazal Najafi
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Khashayar Khaleghi
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Beatriz Garcillán
- University of Melbourne, School of Biomedical Sciences, Parkville, VIC 3010, Australia
| | - Angela Li
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada; Toronto General Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Rickvinder Besla
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada; Department of Laboratory and Medicine Pathology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ikbel Naouar
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Eric Y Cao
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Pailin Chiaranunt
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Kyle Burrows
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Hannah G Robinson
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jessica R Allanach
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jennifer Yam
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Helen Luck
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada; Toronto General Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Daniel J Campbell
- Benaroya Research Institute and Department of Immunology University of Washington School of Medicine, Seattle, WA 98101, USA
| | - David Allman
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David G Brooks
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2M9, Canada
| | - Michio Tomura
- Laboratory of Immunology, Faculty of Pharmacy, Osaka Ohtani University, Tondabayashi, Osaka Prefecture 584-8540, Japan
| | - Ryan Baumann
- Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Scott S Zamvil
- Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA; Program in Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Amit Bar-Or
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marc S Horwitz
- Department of Laboratory and Medicine Pathology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Daniel A Winer
- Toronto General Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada; Department of Laboratory and Medicine Pathology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Arthur Mortha
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Fabienne Mackay
- University of Melbourne, School of Biomedical Sciences, Parkville, VIC 3010, Australia
| | - Alexandre Prat
- Neuroimmunology Unit, CRCHUM and Department of Neurosciences, Faculty of Medicine, Université de Montréal, QC H2X 0A9, Canada
| | - Lisa C Osborne
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Clinton Robbins
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada; Toronto General Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada; Department of Laboratory and Medicine Pathology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Sergio E Baranzini
- Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA; Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, USA; Graduate Program in Bioinformatics, University of California, San Francisco, San Francisco, CA 94143, USA
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Mouat IC, Morse ZJ, Jean-Baptiste VSE, Allanach JR, Horwitz MS. Fresh Ideas, Foundational Experiments (FIFE): Immunology and Diabetes 2016 FIFE Symposium. Front Endocrinol (Lausanne) 2017; 8:238. [PMID: 28974943 PMCID: PMC5610696 DOI: 10.3389/fendo.2017.00238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/30/2017] [Indexed: 12/16/2022] Open
Abstract
The first Fresh Ideas, Foundational Experiments (FIFE): Immunology and Diabetes symposia workshop took place in 2016 and exemplified the active interest of a number of several investigators interested the global rise in the incidence of type 1 diabetes (T1D). This increase does not correlate with genetic drift and indicates that environmental exposures are playing an increasingly significant role. Despite major biomedical and technological advances in diagnosis and treatment, treatments are frequently insufficient as they do not inhibit the progression of the underlying autoimmune response and often fail to prevent life-threatening complications. T1D is the result of autoimmune destruction of the insulin-producing beta cells of the pancreas, and the precise, mechanistic contribution of the immune system to disease pathogenesis and progression remains to be fully characterized. Ultimately, the combinatorial effect of concurrent factors, including beta cell fragility, exogenous stressors, and genetic priming of the innate and adaptive immune system, work together to induce T1D autoimmunity. Thus, T1D is the result of immunological defects and environmental pathogens, requiring the sustained attention of collaborative research teams such as FIFE: I & D with varied perspectives, unified by the universally held goal of finding a sustainable, life-long cure. Herein, the authors provide perspective on various fields in T1D research highlighted by speakers participating in the inaugural FIFE symposium.
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Affiliation(s)
- Isobel C. Mouat
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Zachary J. Morse
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | | | - Jessica R. Allanach
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Marc S. Horwitz
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Marc S. Horwitz,
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Zorz JK, Allanach JR, Murphy CD, Roodvoets MS, Campbell DA, Cockshutt AM. The RUBISCO to Photosystem II Ratio Limits the Maximum Photosynthetic Rate in Picocyanobacteria. Life (Basel) 2015; 5:403-17. [PMID: 25658887 PMCID: PMC4390859 DOI: 10.3390/life5010403] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 01/12/2015] [Accepted: 01/22/2015] [Indexed: 01/22/2023] Open
Abstract
Marine Synechococcus and Prochlorococcus are picocyanobacteria predominating in subtropical, oligotrophic marine environments, a niche predicted to expand with climate change. When grown under common low light conditions Synechococcus WH 8102 and Prochlorococcus MED 4 show similar Cytochrome b6f and Photosystem I contents normalized to Photosystem II content, while Prochlorococcus MIT 9313 has twice the Cytochrome b6f content and four times the Photosystem I content of the other strains. Interestingly, the Prochlorococcus strains contain only one third to one half of the RUBISCO catalytic subunits compared to the marine Synechococcus strain. The maximum Photosystem II electron transport rates were similar for the two Prochlorococcus strains but higher for the marine Synechococcus strain. Photosystem II electron transport capacity is highly correlated to the molar ratio of RUBISCO active sites to Photosystem II but not to the ratio of cytochrome b6f to Photosystem II, nor to the ratio of Photosystem I: Photosystem II. Thus, the catalytic capacity for the rate-limiting step of carbon fixation, the ultimate electron sink, appears to limit electron transport rates. The high abundance of Cytochrome b6f and Photosystem I in MIT 9313, combined with the slower flow of electrons away from Photosystem II and the relatively low level of RUBISCO, are consistent with cyclic electron flow around Photosystem I in this strain.
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Affiliation(s)
- Jackie K Zorz
- Department of Chemistry & Biochemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G8, Canada.
| | - Jessica R Allanach
- Department of Chemistry & Biochemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G8, Canada.
| | - Cole D Murphy
- Department of Chemistry & Biochemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G8, Canada.
| | - Mitchell S Roodvoets
- Department of Chemistry & Biochemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G8, Canada.
| | - Douglas A Campbell
- Department of Chemistry & Biochemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G8, Canada.
| | - Amanda M Cockshutt
- Department of Chemistry & Biochemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G8, Canada.
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Allanach JR. Treatment of rabid-bat bite. Can Med Assoc J 1981; 124:1432-4. [PMID: 7237323 PMCID: PMC1862343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Allanach JR. Suspected adverse reaction to measles virus vaccine. Can Med Assoc J 1969; 101:117. [PMID: 20311485 PMCID: PMC1946333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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