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Kornfeld SF, Cummings SE, Yaworski R, De Repentigny Y, Gagnon S, Zandee S, Fathi S, Prat A, Kothary R. Loss of miR-145 promotes remyelination and functional recovery in a model of chronic central demyelination. Commun Biol 2024; 7:813. [PMID: 38965401 PMCID: PMC11224363 DOI: 10.1038/s42003-024-06513-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 06/27/2024] [Indexed: 07/06/2024] Open
Abstract
Strategies for treating progressive multiple sclerosis (MS) remain limited. Here, we found that miR-145-5p is overabundant uniquely in chronic lesion tissues from secondary progressive MS patients. We induced both acute and chronic demyelination in miR-145 knockout mice to determine its contributions to remyelination failure. Following acute demyelination, no advantage to miR-145 loss could be detected. However, after chronic demyelination, animals with miR-145 loss demonstrated increased remyelination and functional recovery, coincident with altered presence of astrocytes and microglia within the corpus callosum relative to wild-type animals. This improved response in miR-145 knockout animals coincided with a pathological upregulation of miR-145-5p in wild-type animals with chronic cuprizone exposure, paralleling human chronic lesions. Furthermore, miR-145 overexpression specifically in oligodendrocytes (OLs) severely stunted differentiation and negatively impacted survival. RNAseq analysis showed altered transcriptome in these cells with downregulated major pathways involved in myelination. Our data suggest that pathological accumulation of miR-145-5p is a distinctive feature of chronic demyelination and is strongly implicated in the failure of remyelination, possibly due to the inhibition of OL differentiation together with alterations in other glial cells. This is mirrored in chronic MS lesions, and thus miR-145-5p serves as a potential relevant therapeutic target in progressive forms of MS.
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Affiliation(s)
- Samantha F Kornfeld
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Sarah E Cummings
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Rebecca Yaworski
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Sabrina Gagnon
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Stephanie Zandee
- Neuroimmunology Unit and Multiple Sclerosis Clinic, The Research Center of the Centre Hospitalier de l'Université de Montréal (CRCHUM), Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Samaneh Fathi
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Alexandre Prat
- Neuroimmunology Unit and Multiple Sclerosis Clinic, The Research Center of the Centre Hospitalier de l'Université de Montréal (CRCHUM), Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada.
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
- Department of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
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Li V, Binder MD, Purcell AW, Kilpatrick TJ. Antigen-specific immunotherapy via delivery of tolerogenic dendritic cells for multiple sclerosis. J Neuroimmunol 2024; 390:578347. [PMID: 38663308 DOI: 10.1016/j.jneuroim.2024.578347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/22/2024] [Accepted: 04/17/2024] [Indexed: 05/13/2024]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system resulting from loss of immune tolerance. Many disease-modifying therapies for MS have broad immunosuppressive effects on peripheral immune cells, but this can increase risks of infection and attenuate vaccine-elicited immunity. A more targeted approach is to re-establish immune tolerance in an autoantigen-specific manner. This review discusses methods to achieve this, focusing on tolerogenic dendritic cells. Clinical trials in other autoimmune diseases also provide learnings with regards to clinical translation of this approach, including identification of autoantigen(s), selection of appropriate patients and administration route and frequency.
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Affiliation(s)
- Vivien Li
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, Australia; Department of Neurology, The Royal Melbourne Hospital, Melbourne, Australia.
| | - Michele D Binder
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, Australia
| | - Anthony W Purcell
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Trevor J Kilpatrick
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, Australia; Department of Neurology, The Royal Melbourne Hospital, Melbourne, Australia
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Binder MD, Nwoke EC, Morwitch E, Dwyer C, Li V, Xavier A, Lea RA, Lechner-Scott J, Taylor BV, Ponsonby AL, Kilpatrick TJ. HLA-DRB1*15:01 and the MERTK Gene Interact to Selectively Influence the Profile of MERTK-Expressing Monocytes in Both Health and MS. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2024; 11:e200190. [PMID: 38150649 PMCID: PMC10752576 DOI: 10.1212/nxi.0000000000200190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/31/2023] [Indexed: 12/29/2023]
Abstract
BACKGROUND AND OBJECTIVES HLA-DRB1*15:01 (DR15) and MERTK are 2 risk genes for multiple sclerosis (MS). The variant rs7422195 is an expression quantitative trait locus for MERTK in CD14+ monocytes; cells with phagocytic and immunomodulatory potential. We aimed to understand how drivers of disease risk and pathogenesis vary with HLA and MERTK genotype and disease activity. METHODS We investigated how proportions of monocytes vary with HLA and MERTK genotype and disease activity in MS. CD14+ monocytes were isolated from patients with MS at relapse (n = 40) and 3 months later (n = 23). Healthy controls (HCs) underwent 2 blood collections 3 months apart. Immunophenotypic profiling of monocytes was performed by flow cytometry. Methylation of 35 CpG sites within and near the MERTK gene was assessed in whole blood samples of individuals experiencing their first episode of clinical CNS demyelination (n = 204) and matched HCs (n = 345) using an Illumina EPIC array. RESULTS DR15-positive patients had lower proportions of CD14+ MERTK+ monocytes than DR15-negative patients, independent of genotype at the MERTK SNP rs7422195. Proportions of CD14+ MERTK+ monocytes were further reduced during relapse in DR15-positive but not DR15-negative patients. Patients homozygous for the major G allele at rs7422195 exhibited higher proportions of CD14+ MERTK+ monocytes at both relapse and remission compared with controls. We observed that increased methylation of the MERTK gene was significantly associated with the presence of DR15. DISCUSSION DR15 and MERTK genotype independently influence proportions of CD14+ MERTK+ monocytes in MS. We confirmed previous observations that the MERTK risk SNP rs7422195 is associated with altered MERTK expression in monocytes. We identified that expression of MERTK is stratified by disease in people homozygous for the major G allele of rs7422195. The finding that the proportion of CD14+ MERTK+ monocytes is reduced in DR15-positive individuals supports prior data identifying genetic links between these 2 loci in influencing MS risk. DR15 genotype-dependent alterations in methylation of the MERTK gene provides a molecular link between these loci and identifies a potential mechanism by which MERTK expression is influenced by DR15. This links DR15 haplotype to MS susceptibility beyond direct influence on antigen presentation and suggests the need for HLA-based stratification of approaches to MERTK as a therapeutic target.
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Affiliation(s)
- Michele D Binder
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Eze C Nwoke
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Ellen Morwitch
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Chris Dwyer
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Vivien Li
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Alexandre Xavier
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Rodney A Lea
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Jeannette Lechner-Scott
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Bruce V Taylor
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Anne-Louise Ponsonby
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
| | - Trevor J Kilpatrick
- From the Florey Institute of Neuroscience and Mental Health (M.D.B., E.C.N., E.M., C.D., V.L., A.-L.P., T.J.K.); Department of Anatomy and Physiology (M.D.B.), University of Melbourne, Parkville; Crux Biolabs (E.C.N.), Bayswater; Department of Neurology (C.D.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.X., J.L.-S.), John Hunter Hospital, Newcastle; Hunter Medical Research Institute (A.X., J.L.-S.), University of Newcastle, New South Wales Genomics Research Centre (R.A.L.), Centre of Genomics and Personalised Health, Queensland University of Technology; and Menzies Institute for Medical Research (B.V.T.), University of Tasmania, Hobart, Australia
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Nguyen LT, Aprico A, Nwoke E, Walsh AD, Blades F, Avneri R, Martin E, Zalc B, Kilpatrick TJ, Binder MD. Mertk-expressing microglia influence oligodendrogenesis and myelin modelling in the CNS. J Neuroinflammation 2023; 20:253. [PMID: 37926818 PMCID: PMC10626688 DOI: 10.1186/s12974-023-02921-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/04/2023] [Indexed: 11/07/2023] Open
Abstract
BACKGROUND Microglia, an immune cell found exclusively within the CNS, initially develop from haematopoietic stem cell precursors in the yolk sac and colonise all regions of the CNS early in development. Microglia have been demonstrated to play an important role in the development of oligodendrocytes, the myelin producing cells in the CNS, as well as in myelination. Mertk is a receptor expressed on microglia that mediates immunoregulatory functions, including myelin efferocytosis. FINDINGS Here we demonstrate an unexpected role for Mertk-expressing microglia in both oligodendrogenesis and myelination. The selective depletion of Mertk from microglia resulted in reduced oligodendrocyte production in early development and the generation of pathological myelin. During demyelination, mice deficient in microglial Mertk had thinner myelin and showed signs of impaired OPC differentiation. We established that Mertk signalling inhibition impairs oligodendrocyte repopulation in Xenopus tadpoles following demyelination. CONCLUSION These data highlight the importance of microglia in myelination and are the first to identify Mertk as a regulator of oligodendrogenesis and myelin ultrastructure.
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Affiliation(s)
- Linda T Nguyen
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Melbourne, Australia
| | - Andrea Aprico
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
| | - Eze Nwoke
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
- Crux Biolabs, Bayswater, VIC, 3153, Australia
| | - Alexander D Walsh
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
- Cognitive Neuroepigenetics Laboratory, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Farrah Blades
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
- Centre for Solar Biotechnology, Institute for Molecular Biosciences, University of Queensland, St Lucia, Brisbane, Australia
| | - Raphael Avneri
- Inserm, CNRS, Institut du Cerveau, AP-HP Pitié-Salpêtrière Hospital, Sorbonne Université, Paris, France
- Department of Molecular Biology, Ariel University, 40700, Ariel, Israel
| | - Elodie Martin
- Inserm, CNRS, Institut du Cerveau, AP-HP Pitié-Salpêtrière Hospital, Sorbonne Université, Paris, France
| | - Bernard Zalc
- Inserm, CNRS, Institut du Cerveau, AP-HP Pitié-Salpêtrière Hospital, Sorbonne Université, Paris, France
| | - Trevor J Kilpatrick
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
| | - Michele D Binder
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia.
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Melbourne, Australia.
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TAM receptor signaling dictates lesion location and clinical phenotype during experimental autoimmune encephalomyelitis. J Neuroimmunol 2023; 375:578016. [PMID: 36708633 DOI: 10.1016/j.jneuroim.2023.578016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/22/2022] [Accepted: 01/06/2023] [Indexed: 01/21/2023]
Abstract
Experimental autoimmune encephalomyelitis (EAE), induced by the adoptive transfer of Th17 cells, typically presents with ascending paralysis and inflammatory demyelination of the spinal cord. Brain white matter is relatively spared. Here we show that treatment of Th17 transfer recipients with a highly selective inhibitor to the TAM family of tyrosine kinase receptors results in ataxia associated with a shift of the inflammatory infiltrate to the hindbrain parenchyma. During homeostasis and preclinical EAE, hindbrain microglia express high levels of the TAM receptor Mer. Our data suggest that constitutive TAM receptor signaling in hindbrain microglia confers region-specific protection against Th17 mediated EAE.
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Phosphatidylserine in the Nervous System: Cytoplasmic Regulator of the AKT and PKC Signaling Pathways and Extracellular "Eat-Me" Signal in Microglial Phagocytosis. Mol Neurobiol 2023; 60:1050-1066. [PMID: 36401705 DOI: 10.1007/s12035-022-03133-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/08/2022] [Indexed: 11/21/2022]
Abstract
Phosphatidylserine (PtdSer) is an important anionic phospholipid found in eukaryotic cells and has been proven to serve as a beneficial factor in the treatment of neurodegenerative diseases. PtdSer resides in the inner leaflet of the plasma membrane, where it is involved in regulating the AKT and PKC signaling pathways; however, it becomes exposed to the extracellular leaflet during neurodevelopmental processes and neurodegenerative diseases, participating in microglia-mediated synaptic and neuronal phagocytosis. In this paper, we review several characteristics of PtdSer, including the synthesis and translocation of PtdSer, the functions of cytoplasmic and exposed PtdSer, and different PtdSer-detection materials used to further understand the role of PtdSer in the nervous system.
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Goris A, Vandebergh M, McCauley JL, Saarela J, Cotsapas C. Genetics of multiple sclerosis: lessons from polygenicity. Lancet Neurol 2022; 21:830-842. [PMID: 35963264 DOI: 10.1016/s1474-4422(22)00255-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/07/2022] [Accepted: 04/12/2022] [Indexed: 11/27/2022]
Abstract
Large-scale mapping studies have identified 236 independent genetic variants associated with an increased risk of multiple sclerosis. However, none of these variants are found exclusively in patients with multiple sclerosis. They are located throughout the genome, including 32 independent variants in the MHC and one on the X chromosome. Most variants are non-coding and seem to act through cell-specific effects on gene expression and splicing. The likely functions of these variants implicate both adaptive and innate immune cells in the pathogenesis of multiple sclerosis, provide pivotal biological insight into the causes and mechanisms of multiple sclerosis, and some of the variants implicated in multiple sclerosis also mediate risk of other autoimmune and inflammatory diseases. Genetics offers an approach to showing causality for environmental factors, through Mendelian randomisation. No single variant is necessary or sufficient to cause multiple sclerosis; instead, each increases total risk in an additive manner. This combined contribution from many genetic factors to disease risk, or polygenicity, has important consequences for how we interpret the epidemiology of multiple sclerosis and how we counsel patients on risk and prognosis. Ongoing efforts are focused on increasing cohort sizes, increasing diversity and detailed characterisation of study populations, and translating these associations into an understanding of the biology of multiple sclerosis.
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Affiliation(s)
- An Goris
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Laboratory for Neuroimmunology, Leuven, Belgium.
| | - Marijne Vandebergh
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Laboratory for Neuroimmunology, Leuven, Belgium
| | - Jacob L McCauley
- John P Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Janna Saarela
- Centre for Molecular Medicine Norway, University of Oslo, Oslo, Norway; Institute for Molecular Medicine Finland and Department of Clinical Genetics, Helsinki University Hospital, University of Helsinki, Helsinki, Finland; Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Chris Cotsapas
- Departments of Neurology and Genetics, Yale School of Medicine, New Haven, CT, USA
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Jansen MI, Thomas Broome S, Castorina A. Exploring the Pro-Phagocytic and Anti-Inflammatory Functions of PACAP and VIP in Microglia: Implications for Multiple Sclerosis. Int J Mol Sci 2022; 23:ijms23094788. [PMID: 35563181 PMCID: PMC9104531 DOI: 10.3390/ijms23094788] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/22/2022] [Accepted: 04/25/2022] [Indexed: 02/04/2023] Open
Abstract
Multiple sclerosis (MS) is a chronic neuroinflammatory and demyelinating disease of the central nervous system (CNS), characterised by the infiltration of peripheral immune cells, multifocal white-matter lesions, and neurodegeneration. In recent years, microglia have emerged as key contributors to MS pathology, acting as scavengers of toxic myelin/cell debris and modulating the inflammatory microenvironment to promote myelin repair. In this review, we explore the role of two neuropeptides, pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP), as important regulators of microglial functioning during demyelination, myelin phagocytosis, and remyelination, emphasising the potential of these neuropeptides as therapeutic targets for the treatment of MS.
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Wong SW, Vivash L, Mudududdla R, Nguyen N, Hermans SJ, Shackleford DM, Field J, Xue L, Aprico A, Hancock NC, Haskali M, Stashko MA, Frye SV, Wang X, Binder MD, Ackermann U, Parker MW, Kilpatrick TJ, Baell JB. Development of [ 18F]MIPS15692, a radiotracer with in vitro proof-of-concept for the imaging of MER tyrosine kinase (MERTK) in neuroinflammatory disease. Eur J Med Chem 2021; 226:113822. [PMID: 34563964 DOI: 10.1016/j.ejmech.2021.113822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022]
Abstract
MER tyrosine kinase (MERTK) upregulation is associated with M2 polarization of microglia, which plays a vital role in neuroregeneration following damage induced by neuroinflammatory diseases such as multiple sclerosis (MS). Therefore, a radiotracer specific for MERTK could be of great utility in the clinical management of MS, for the detection and differentiation of neuroregenerative and neurodegenerative processes. This study aimed to develop an [18F] ligand with high affinity and selectivity for MERTK as a potential positron emission tomography (PET) radiotracer. MIPS15691 and MIPS15692 were synthesized and kinase assays were utilized to determine potency and selectivity for MERTK. Both compounds were shown to be potent against MERTK, with respective IC50 values of 4.6 nM and 4.0 nM, and were also MERTK-selective. Plasma and brain pharmacokinetics were measured in mice and led to selection of MIPS15692 over MIPS15691. X-ray crystallography was used to visualize how MIPS15692 is recognized by the enzyme. [18F]MIPS15692 was synthesized using an automated iPHASE FlexLab module, with a molar activity (Am) of 49 ± 26 GBq/μmol. The radiochemical purity of [18F]MIPS15692 was >99% and the decay-corrected radiochemical yields (RCYs) were determined as 2.45 ± 0.85%. Brain MERTK protein density was measured by a saturation binding assay in the brain slices of a cuprizone mouse model of MS. High levels of specific binding of [18F]MIPS15692 to MERTK were found, especially in the corpus callosum/hippocampus (CC/HC). The in vivo PET imaging study of [18F]MIPS15692 suggested that its neuroPK is sub-optimal for clinical use. Current efforts are underway to optimize the neuroPK of our next generation PET radiotracers for maximal in vivo utility.
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Affiliation(s)
- Siu Wai Wong
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Lucy Vivash
- The Central Clinical School and The Alfred Hospital, Monash University, Melbourne, Victoria, Australia
| | - Ramesh Mudududdla
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Nghi Nguyen
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Stefan J Hermans
- ACRF Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, Victoria, 3065, Australia
| | - David M Shackleford
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Judith Field
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, 3010, Australia
| | - Lian Xue
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Andrea Aprico
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, 3010, Australia
| | - Nancy C Hancock
- ACRF Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, Victoria, 3065, Australia
| | - Mohammad Haskali
- Centre for Molecular Imaging, Peter MacCallum Cancer Centre, Parkville, Victoria, 3052, Australia
| | - Michael A Stashko
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States
| | - Stephen V Frye
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States
| | - Xiaodong Wang
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States
| | - Michele D Binder
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, 3010, Australia; Department of Anatomy and Physiology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Uwe Ackermann
- Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, Victoria, 3084, Australia
| | - Michael W Parker
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia; ACRF Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, Victoria, 3065, Australia
| | - Trevor J Kilpatrick
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, 3010, Australia; The Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, 3010, Australia.
| | - Jonathan B Baell
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China; Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia.
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10
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Walsh AD, Johnson LJ, Harvey AJ, Kilpatrick TJ, Binder MD. Identification and Characterisation of cis-Regulatory Elements Upstream of the Human Receptor Tyrosine Kinase Gene MERTK. Brain Plast 2021; 7:3-16. [PMID: 34631417 PMCID: PMC8461731 DOI: 10.3233/bpl-200102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND: MERTK encodes a receptor tyrosine kinase that regulates immune homeostasis via phagocytosis of apoptotic cells and cytokine-mediated immunosuppression. MERTK is highly expressed in the central nervous system (CNS), specifically in myeloid derived innate immune cells and its dysregulation is implicated in CNS pathologies including the autoimmune disease multiple sclerosis (MS). OBJECTIVE: While the cell types and tissues that express MERTK have been well described, the genetic elements that define the gene’s promoter and regulate specific transcription domains remain unknown. The primary objective of this study was to define and characterise the human MERTK promoter region. METHODS: We cloned and characterized the 5’ upstream region of MERTK to identify cis-acting DNA elements that promote gene transcription in luciferase reporter assays. In addition, promoter regions were tested for sensitivity to the anti-inflammatory glucocorticoid dexamethasone. RESULTS: This study identified identified both proximal and distal-acting DNA elements that promote transcription. The strongest promoter activity was identified in an ∼850 bp region situated 3 kb upstream of the MERTK transcription start site. Serial deletions of this putative enhancer revealed that the entire region is essential for expression activity. Using in silico analysis, we identified several candidate transcription factor binding sites. Despite a well-established upregulation of MERTK in response to anti-inflammatory glucocorticoids, no DNA region within the 5 kb putative promoter was found to directly respond to dexamethasone treatment. CONCLUSIONS: Elucidating the genetic mechanisms that regulate MERTK expression gives insights into gene regulation during homeostasis and disease, providing potential targets for therapeutic modulation of MERTK transcription.
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Affiliation(s)
- Alexander D. Walsh
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
| | - Laura J. Johnson
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
| | - Alexandra J. Harvey
- School of BioSciences, University of Melbourne, Parkville, Melbourne, Australia
| | - Trevor J. Kilpatrick
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
- The Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia
| | - Michele D. Binder
- The Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Melbourne, Australia
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11
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Abstract
Tyro3, Axl and Mertk are members of the TAM family of tyrosine kinase receptors. TAMs are activated by two structurally homologous ligands GAS6 and PROS1. TAM receptors and ligands are widely distributed and often co-expressed in the same cells allowing diverse functions across many systems including the immune, reproductive, vascular, and the developing as well as adult nervous systems. This review will focus specifically on TAM signaling in the nervous system, highlighting the essential roles this pathway fulfills in maintaining cell survival and homeostasis, cellular functions such as phagocytosis, immunity and tissue repair. Dysfunctional TAM signaling can cause complications in development, disruptions in homeostasis which can rouse autoimmunity, neuroinflammation and neurodegeneration. The development of therapeutics modulating TAM activities in the nervous system has great prospects, however, foremost we need a complete understanding of TAM signaling pathways.
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Affiliation(s)
- Tal Burstyn-Cohen
- Institute for Dental Sciences, Faculty of Dental Medicine, The Hebrew University-Hadassah, Jerusalem, Israel
| | - Arielle Hochberg
- Institute for Dental Sciences, Faculty of Dental Medicine, The Hebrew University-Hadassah, Jerusalem, Israel
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12
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Having an Old Friend for Dinner: The Interplay between Apoptotic Cells and Efferocytes. Cells 2021; 10:cells10051265. [PMID: 34065321 PMCID: PMC8161178 DOI: 10.3390/cells10051265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 02/02/2023] Open
Abstract
Apoptosis, the programmed and intentional death of senescent, damaged, or otherwise superfluous cells, is the natural end-point for most cells within multicellular organisms. Apoptotic cells are not inherently damaging, but if left unattended, they can lyse through secondary necrosis. The resulting release of intracellular contents drives inflammation in the surrounding tissue and can lead to autoimmunity. These negative consequences of secondary necrosis are avoided by efferocytosis—the phagocytic clearance of apoptotic cells. Efferocytosis is a product of both apoptotic cells and efferocyte mechanisms, which cooperate to ensure the rapid and complete removal of apoptotic cells. Herein, we review the processes used by apoptotic cells to ensure their timely removal, and the receptors, signaling, and cellular processes used by efferocytes for efferocytosis, with a focus on the receptors and signaling driving this process.
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13
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Zhou L, Matsushima GK. Tyro3, Axl, Mertk receptor-mediated efferocytosis and immune regulation in the tumor environment. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 361:165-210. [PMID: 34074493 DOI: 10.1016/bs.ircmb.2021.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Three structurally related tyrosine receptor cell surface kinases, Tyro3, Axl, and Mertk (TAM) have been recognized to modulate immune function, tissue homeostasis, cardiovasculature, and cancer. The TAM receptor family appears to operate in adult mammals across multiple cell types, suggesting both widespread and specific regulation of cell functions and immune niches. TAM family members regulate tissue homeostasis by monitoring the presence of phosphatidylserine expressed on stressed or apoptotic cells. The detection of phosphatidylserine on apoptotic cells requires intermediary molecules that opsonize the dying cells and tether them to TAM receptors on phagocytes. This complex promotes the engulfment of apoptotic cells, also known as efferocytosis, that leads to the resolution of inflammation and tissue healing. The immune mechanisms dictating these processes appear to fall upon specific family members or may involve a complex of different receptors acting cooperatively to resolve and repair damaged tissues. Here, we focus on the role of TAM receptors in triggering efferocytosis and its consequences in the regulation of immune responses in the context of inflammation and cancer.
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Affiliation(s)
- Liwen Zhou
- UNC Neuroscience Center, University of North Carolina-CH, Chapel Hill, NC, United States
| | - Glenn K Matsushima
- UNC Neuroscience Center, University of North Carolina-CH, Chapel Hill, NC, United States; UNC Department of Microbiology & Immunology, University of North Carolina-CH, Chapel Hill, NC, United States; UNC Integrative Program for Biological & Genome Sciences, University of North Carolina-CH, Chapel Hill, NC, United States.
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14
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Yin C, Heit B. Cellular Responses to the Efferocytosis of Apoptotic Cells. Front Immunol 2021; 12:631714. [PMID: 33959122 PMCID: PMC8093429 DOI: 10.3389/fimmu.2021.631714] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/29/2021] [Indexed: 12/17/2022] Open
Abstract
The rapid and efficient phagocytic clearance of apoptotic cells, termed efferocytosis, is a critical mechanism in the maintenance of tissue homeostasis. Removal of apoptotic cells through efferocytosis prevents secondary necrosis and the resultant inflammation caused by the release of intracellular contents. The importance of efferocytosis in homeostasis is underscored by the large number of inflammatory and autoimmune disorders, including atherosclerosis and systemic lupus erythematosus, that are characterized by defective apoptotic cell clearance. Although mechanistically similar to the phagocytic clearance of pathogens, efferocytosis differs from phagocytosis in that it is immunologically silent and induces a tissue repair response. Efferocytes face unique challenges resulting from the internalization of apoptotic cells, including degradation of the apoptotic cell, dealing with the extra metabolic load imposed by the processing of apoptotic cell contents, and the coordination of an anti-inflammatory, pro-tissue repair response. This review will discuss recent advances in our understanding of the cellular response to apoptotic cell uptake, including trafficking of apoptotic cell cargo and antigen presentation, signaling and transcriptional events initiated by efferocytosis, the coordination of an anti-inflammatory response and tissue repair, unique cellular metabolic responses and the role of efferocytosis in host defense. A better understanding of how efferocytic cells respond to apoptotic cell uptake will be critical in unraveling the complex connections between apoptotic cell removal and inflammation resolution and maintenance of tissue homeostasis.
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Affiliation(s)
- Charles Yin
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Center for Human Immunology, Western University, London, ON, Canada
| | - Bryan Heit
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Center for Human Immunology, Western University, London, ON, Canada
- Robarts Research Institute, London, ON, Canada
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15
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Dou M, Zhou X, Li L, Zhang M, Wang W, Wang M, Jing Y, Ma R, Zhao J, Zhu L. Illumination of Molecular Pathways in Multiple Sclerosis Lesions and the Immune Mechanism of Matrine Treatment in EAE, a Mouse Model of MS. Front Immunol 2021; 12:640778. [PMID: 33912166 PMCID: PMC8072148 DOI: 10.3389/fimmu.2021.640778] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
The etiology of multiple sclerosis (MS) is not clear, and the treatment of MS presents a great challenge. This study aimed to investigate the pathogenesis and potential therapeutic targets of MS and to define target genes of matrine, a quinolizidine alkaloid component derived from the root of Sophorae flavescens that effectively suppressed experimental autoimmune encephalomyelitis (EAE), an animal model of MS. To this end, the GSE108000 gene data set in the Gene Expression Omnibus Database, which included 7 chronic active MS lesions and 10 control samples of white matter, was analyzed for differentially expressed genes (DEGs). X cell was used to analyze the microenvironmental differences in brain tissue samples of MS patients, including 64 types of immune cells and stromal cells. The biological functions and enriched signaling pathways of DEGs were analyzed by multiple approaches, including GO, KEGG, GSEA, and GSVA. The results by X cell showed significantly increased numbers of immune cell populations in the MS lesions, with decreased erythrocytes, megakaryocytes, adipocytes, keratinocytes, endothelial cells, Th1 cells and Tregs. In GSE108000, there were 637 DEGs, including 428 up-regulated and 209 down-regulated genes. Potential target genes of matrine were then predicted by the network pharmacology method of Traditional Chinese medicine, and 12 key genes were obtained by cross analysis of the target genes of matrine and DEGs in MS lesions. Finally, we confirmed by RT-PCR the predicted expression of these genes in brain tissues of matrine-treated EAE mice. Among these genes, 2 were significantly downregulated and 6 upregulated by matrine treatment, and the significance of this gene regulation was further investigated. In conclusion, our study defined several possible matrine target genes, which can be further elucidated as mechanism(s) of matrine action, and novel targets in the treatment of MS.
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Affiliation(s)
- Mengmeng Dou
- Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Department of Neurology, the Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xueliang Zhou
- Department of Interventional Radiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Lifeng Li
- Department of Oncology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Internet Medical and System Applications of National Engineering Laboratory, Zhengzhou, China
| | - Mingliang Zhang
- Department of Pharmacy, the first Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Wenbin Wang
- Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Department of Neurology, the Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Mengru Wang
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yilei Jing
- Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Rui Ma
- Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jie Zhao
- Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Internet Medical and System Applications of National Engineering Laboratory, Zhengzhou, China
| | - Lin Zhu
- Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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16
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Dwyer CM, Nguyen LTT, Healy LM, Dutta R, Ludwin S, Antel J, Binder MD, Kilpatrick TJ. Multiple Sclerosis as a Syndrome-Implications for Future Management. Front Neurol 2020; 11:784. [PMID: 32982904 PMCID: PMC7483755 DOI: 10.3389/fneur.2020.00784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/25/2020] [Indexed: 12/25/2022] Open
Abstract
We propose that multiple sclerosis (MS) is best characterized as a syndrome rather than a single disease because different pathogenetic mechanisms can result in the constellation of symptoms and signs by which MS is clinically characterized. We describe several cellular mechanisms that could generate inflammatory demyelination through disruption of homeostatic interactions between immune and neural cells. We illustrate that genomics is important in identifying phenocopies, in particular for primary progressive MS. We posit that molecular profiling, rather than traditional clinical phenotyping, will facilitate meaningful patient stratification, as illustrated by interactions between HLA and a regulator of homeostatic phagocytosis, MERTK. We envisage a personalized approach to MS management where genetic, molecular, and cellular information guides management.
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Affiliation(s)
- Christopher M Dwyer
- Florey Institute of Neuroscience and Mental Health, Florey Department, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Linda Thien-Trang Nguyen
- Florey Institute of Neuroscience and Mental Health, Florey Department, The University of Melbourne, Parkville, VIC, Australia
| | - Luke M Healy
- Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Ranjan Dutta
- Department of Neurosciences, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Samuel Ludwin
- Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Jack Antel
- Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Michele D Binder
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
| | - Trevor J Kilpatrick
- Florey Institute of Neuroscience and Mental Health, Florey Department, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, VIC, Australia
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17
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Clarke J, Yaqubi M, Futhey NC, Sedaghat S, Baufeld C, Blain M, Baranzini S, Butovsky O, Antel J, White JH, Healy LM. Vitamin D Regulates MerTK-Dependent Phagocytosis in Human Myeloid Cells. THE JOURNAL OF IMMUNOLOGY 2020; 205:398-406. [PMID: 32540991 DOI: 10.4049/jimmunol.2000129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/17/2020] [Indexed: 01/08/2023]
Abstract
Vitamin D deficiency is a major environmental risk factor for the development of multiple sclerosis. The major circulating metabolite of vitamin D (25-hydroxyvitamin D) is converted to the active form (calcitriol) by the hydroxylase enzyme CYP27B1 In multiple sclerosis lesions, the tyrosine kinase MerTK expressed by myeloid cells regulates phagocytosis of myelin debris and apoptotic cells that can accumulate and inhibit tissue repair and remyelination. In this study, we explored the effect of calcitriol on homeostatic (M-CSF, TGF-β-treated) and proinflammatory (GM-CSF-treated) human monocyte-derived macrophages and microglia using RNA sequencing. Transcriptomic analysis revealed significant calcitriol-mediated effects on both Ag presentation and phagocytosis pathways. Calcitriol downregulated MerTK mRNA and protein expression in both myeloid populations, resulting in reduced capacity of these cells to phagocytose myelin and apoptotic T cells. Proinflammatory myeloid cells expressed high levels of CYP27B1 compared with homeostatic myeloid cells. Only proinflammatory cells in the presence of TNF-α generated calcitriol from 25-hydroxyvitamin D, resulting in repression of MerTK expression and function. This selective production of calcitriol in proinflammatory myeloid cells has the potential to reduce the risk for autoantigen presentation while retaining the phagocytic ability of homeostatic myeloid cells.
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Affiliation(s)
- Jelani Clarke
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Moein Yaqubi
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Naomi C Futhey
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Sara Sedaghat
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Caroline Baufeld
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Manon Blain
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Sergio Baranzini
- Department of Neurology, Weill Institute for Neurosciences, University of California-San Francisco, San Francisco, CA 94115
| | - Oleg Butovsky
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Jack Antel
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - John H White
- Departments of Physiology and Medicine, McGill University, Montreal, Quebec H3A 0G4, Canada; and.,Evergrande Center for Immunologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Luke M Healy
- Neuroimmunology Unit, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 0G4, Canada;
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18
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TAM Receptor Pathways at the Crossroads of Neuroinflammation and Neurodegeneration. DISEASE MARKERS 2019; 2019:2387614. [PMID: 31636733 PMCID: PMC6766163 DOI: 10.1155/2019/2387614] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/04/2019] [Accepted: 08/12/2019] [Indexed: 02/07/2023]
Abstract
Increasing evidence suggests that pathogenic mechanisms underlying neurodegeneration are strongly linked with neuroinflammatory responses. Tyro3, Axl, and Mertk (TAM receptors) constitute a subgroup of the receptor tyrosine kinase family, cell surface receptors which transmit signals from the extracellular space to the cytoplasm and nucleus. TAM receptors and the corresponding ligands, Growth Arrest Specific 6 and Protein S, are expressed in different tissues, including the nervous system, playing complex roles in tissue repair, inflammation and cell survival, proliferation, and migration. In the nervous system, TAM receptor signalling modulates neurogenesis and neuronal migration, synaptic plasticity, microglial activation, phagocytosis, myelination, and peripheral nerve repair, resulting in potential interest in neuroinflammatory and neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Multiple Sclerosis. In Alzheimer and Parkinson diseases, a role of TAM receptors in neuronal survival and pathological protein aggregate clearance has been suggested, while in Multiple Sclerosis TAM receptors are involved in myelination and demyelination processes. To better clarify roles and pathways involving TAM receptors may have important therapeutic implications, given the fine modulation of multiple molecular processes which could be reached. In this review, we summarise the roles of TAM receptors in the central nervous system, focusing on the regulation of immune responses and microglial activities and analysing in vitro and in vivo studies regarding TAM signalling involvement in neurodegeneration.
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19
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Shepard CJ, Cline SG, Hinds D, Jahanbakhsh S, Prokop JW. Breakdown of multiple sclerosis genetics to identify an integrated disease network and potential variant mechanisms. Physiol Genomics 2019; 51:562-577. [PMID: 31482761 DOI: 10.1152/physiolgenomics.00120.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Genetics of multiple sclerosis (MS) are highly polygenic with few insights into mechanistic associations with pathology. In this study, we assessed MS genetics through linkage disequilibrium and missense variant interpretation to yield a MS gene network. This network of 96 genes was taken through pathway analysis, tissue expression profiles, single cell expression segregation, expression quantitative trait loci (eQTLs), genome annotations, transcription factor (TF) binding profiles, structural genome looping, and overlap with additional associated genetic traits. This work revealed immune system dysfunction, nerve cell myelination, energetic control, transcriptional regulation, and variants that overlap multiple autoimmune disorders. Tissue-specific expression and eQTLs of MS genes implicate multiple immune cell types including macrophages, neutrophils, and T cells, while the genes in neural cell types enrich for oligodendrocyte and myelin sheath biology. There are eQTLs in linkage with lead MS variants in 25 genes including the multitissue eQTL, rs9271640, for HLA-DRB1/DRB5. Using multiple functional genomic databases, we identified noncoding variants that disrupt TF binding for GABPA, CTCF, EGR1, YY1, SPI1, CLOCK, ARNTL, BACH1, and GFI1. Overall, this paper suggests multiple genetic mechanisms for MS associated variants while highlighting the importance of a systems biology and network approach when elucidating intersections of the immune and nervous system.
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Affiliation(s)
- C Joy Shepard
- Department of Biology, Athens State University, Athens, Alabama.,Graduate Biomedical Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Sara G Cline
- Department of Biology, Athens State University, Athens, Alabama
| | - David Hinds
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama.,Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan
| | - Seyedehameneh Jahanbakhsh
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan
| | - Jeremy W Prokop
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan.,Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
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20
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Mitrovič M, Patsopoulos NA, Beecham AH, Dankowski T, Goris A, Dubois B, D’hooghe MB, Lemmens R, Van Damme P, Søndergaard HB, Sellebjerg F, Sorensen PS, Ullum H, Thørner LW, Werge T, Saarela J, Cournu-Rebeix I, Damotte V, Fontaine B, Guillot-Noel L, Lathrop M, Vukusik S, Gourraud PA, Andlauer TF, Pongratz V, Buck D, Gasperi C, Bayas A, Heesen C, Kümpfel T, Linker R, Paul F, Stangel M, Tackenberg B, Bergh FT, Warnke C, Wiendl H, Wildemann B, Zettl U, Ziemann U, Tumani H, Gold R, Grummel V, Hemmer B, Knier B, Lill CM, Luessi F, Dardiotis E, Agliardi C, Barizzone N, Mascia E, Bernardinelli L, Comi G, Cusi D, Esposito F, Ferrè L, Comi C, Galimberti D, Leone MA, Sorosina M, Mescheriakova J, Hintzen R, van Duijn C, Teunissen CE, Bos SD, Myhr KM, Celius EG, Lie BA, Spurkland A, Comabella M, Montalban X, Alfredsson L, Stridh P, Hillert J, Jagodic M, Piehl F, Jelčić I, Martin R, Sospedra M, Ban M, Hawkins C, Hysi P, Kalra S, Karpe F, Khadake J, Lachance G, Neville M, Santaniello A, Caillier SJ, Calabresi PA, Cree BA, Cross A, Davis MF, Haines JL, de Bakker PI, Delgado S, Dembele M, Edwards K, Fitzgerald KC, Hakonarson H, Konidari I, Lathi E, Manrique CP, Pericak-Vance MA, Piccio L, Schaefer C, McCabe C, Weiner H, Goldstein J, Olsson T, Hadjigeorgiou G, Taylor B, Tajouri L, Charlesworth J, Booth DR, Harbo HF, Ivinson AJ, Hauser SL, Compston A, Stewart G, Zipp F, Barcellos LF, Baranzini SE, Martinelli-Boneschi F, D’Alfonso S, Ziegler A, Oturai A, McCauley JL, Sawcer SJ, Oksenberg JR, De Jager PL, Kockum I, Hafler DA, Cotsapas C. Low-Frequency and Rare-Coding Variation Contributes to Multiple Sclerosis Risk. Cell 2018; 175:1679-1687.e7. [PMID: 30343897 PMCID: PMC6269166 DOI: 10.1016/j.cell.2018.09.049] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 08/08/2018] [Accepted: 09/24/2018] [Indexed: 12/21/2022]
Abstract
Multiple sclerosis is a complex neurological disease, with ∼20% of risk heritability attributable to common genetic variants, including >230 identified by genome-wide association studies. Multiple strands of evidence suggest that much of the remaining heritability is also due to additive effects of common variants rather than epistasis between these variants or mutations exclusive to individual families. Here, we show in 68,379 cases and controls that up to 5% of this heritability is explained by low-frequency variation in gene coding sequence. We identify four novel genes driving MS risk independently of common-variant signals, highlighting key pathogenic roles for regulatory T cell homeostasis and regulation, IFNγ biology, and NFκB signaling. As low-frequency variants do not show substantial linkage disequilibrium with other variants, and as coding variants are more interpretable and experimentally tractable than non-coding variation, our discoveries constitute a rich resource for dissecting the pathobiology of MS.
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21
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Grajchen E, Hendriks JJA, Bogie JFJ. The physiology of foamy phagocytes in multiple sclerosis. Acta Neuropathol Commun 2018; 6:124. [PMID: 30454040 PMCID: PMC6240956 DOI: 10.1186/s40478-018-0628-8] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 11/02/2018] [Indexed: 12/15/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic disease of the central nervous system characterized by massive infiltration of immune cells, demyelination, and axonal loss. Active MS lesions mainly consist of macrophages and microglia containing abundant intracellular myelin remnants. Initial studies showed that these foamy phagocytes primarily promote MS disease progression by internalizing myelin debris, presenting brain-derived autoantigens, and adopting an inflammatory phenotype. However, more recent studies indicate that phagocytes can also adopt a beneficial phenotype upon myelin internalization. In this review, we summarize and discuss the current knowledge on the spatiotemporal physiology of foamy phagocytes in MS lesions, and elaborate on extrinsic and intrinsic factors regulating their behavior. In addition, we discuss and link the physiology of myelin-containing phagocytes to that of foamy macrophages in other disorders such atherosclerosis.
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Affiliation(s)
- Elien Grajchen
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium/School of Life Sciences, Transnationale Universiteit Limburg, Diepenbeek, Belgium
| | - Jerome J A Hendriks
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium/School of Life Sciences, Transnationale Universiteit Limburg, Diepenbeek, Belgium
| | - Jeroen F J Bogie
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium/School of Life Sciences, Transnationale Universiteit Limburg, Diepenbeek, Belgium.
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22
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Blades F, Aprico A, Akkermann R, Ellis S, Binder MD, Kilpatrick TJ. The TAM receptor TYRO3 is a critical regulator of myelin thickness in the central nervous system. Glia 2018; 66:2209-2220. [PMID: 30208252 DOI: 10.1002/glia.23481] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 05/31/2018] [Accepted: 06/05/2018] [Indexed: 02/03/2023]
Abstract
Multiple sclerosis (MS) is an autoimmune, demyelinating disease of the central nervous system (CNS). Major deficits arise in MS patients due to an inability to repair damaged myelin sheaths following CNS insult, resulting in prolonged axonal exposure and neurodegeneration. The TAM receptors (Tyro3, Axl, and Mertk) have been implicated in MS susceptibility, demyelination and remyelination. Previously, we have shown that Tyro3 regulates developmental myelination and myelin thickness within the optic nerve and rostral region of the corpus callosum (CC) of adult mice. In this study we have verified and extended our previous findings via a comprehensive analysis of axonal ensheathment and myelin thickness in the CC of unchallenged mice, following demyelination and during myelin repair. We show that the loss of the Tyro3 receptor correlates with significantly thinner myelin sheaths in both unchallenged mice and during remyelination, particularly in larger caliber axons. The hypomyelinated phenotype observed in the absence of Tyro3 occurs independently of any influence upon oligodendrocyte precursor cell (OPC) maturation, or density of oligodendrocytes (OLs) or microglia. Rather, the primary effect of Tyro3 is upon the radial expansion of myelin. The loss of Tyro3 leads to a reduction in the number of myelin lamellae on axons, and is therefore most likely a key component of the regulatory mechanism by which oligodendrocytes match myelin production to axonal diameter.
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Affiliation(s)
- Farrah Blades
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia
| | - Andrea Aprico
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia
| | - Rainer Akkermann
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sarah Ellis
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
| | - Michele D Binder
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Trevor J Kilpatrick
- Multiple Sclerosis division, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
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23
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Shafit-Zagardo B, Gruber RC, DuBois JC. The role of TAM family receptors and ligands in the nervous system: From development to pathobiology. Pharmacol Ther 2018. [PMID: 29514053 DOI: 10.1016/j.pharmthera.2018.03.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Tyro3, Axl, and Mertk, referred to as the TAM family of receptor tyrosine kinases, are instrumental in maintaining cell survival and homeostasis in mammals. TAM receptors interact with multiple signaling molecules to regulate cell migration, survival, phagocytosis and clearance of metabolic products and cell debris called efferocytosis. The TAMs also function as rheostats to reduce the expression of proinflammatory molecules and prevent autoimmunity. All three TAM receptors are activated in a concentration-dependent manner by the vitamin K-dependent growth arrest-specific protein 6 (Gas6). Gas6 and the TAMs are abundantly expressed in the nervous system. Gas6, secreted by neurons and endothelial cells, is the sole ligand for Axl. ProteinS1 (ProS1), another vitamin K-dependent protein functions mainly as an anti-coagulant, and independent of this function can activate Tyro3 and Mertk, but not Axl. This review will focus on the role of the TAM receptors and their ligands in the nervous system. We highlight studies that explore the function of TAM signaling in myelination, the visual cortex, neural cancers, and multiple sclerosis (MS) using Gas6-/- and TAM mutant mice models.
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Affiliation(s)
- Bridget Shafit-Zagardo
- Albert Einstein College of Medicine, Department of Pathology, 1300 Morris Park Avenue, Bronx, NY 10461, United States.
| | - Ross C Gruber
- Sanofi, Neuroinflammation and MS Research, 49 New York Ave, Framingham, MA 01701, United States
| | - Juwen C DuBois
- Albert Einstein College of Medicine, Department of Pathology, 1300 Morris Park Avenue, Bronx, NY 10461, United States
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24
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Healy LM, Jang JH, Won SY, Lin YH, Touil H, Aljarallah S, Bar-Or A, Antel JP. MerTK-mediated regulation of myelin phagocytosis by macrophages generated from patients with MS. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2017; 4:e402. [PMID: 29379818 PMCID: PMC5777663 DOI: 10.1212/nxi.0000000000000402] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/09/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To document functional differences between monocyte-derived macrophages (MDMs) of patients with MS and the ability of age/sex-matched healthy donor cells to phagocytose human myelin and to investigate the molecular mechanisms that underlie this. METHODS MDMs were derived from peripheral blood monocytes of 25 untreated patients with relapsing-remitting MS and secondary progressive MS and age/sex-matched healthy controls (HCs). Phagocytosis was assessed by flow cytometry using fluorescently labeled human myelin. Quantification of messenger RNA and protein expression of Tyro3, Axl, and MerTK family molecules was determined by quantitative PCR, Western blotting, and flow cytometry. RESULTS Cells of patients with MS display a reduced ability to phagocytose human myelin but not red blood cells as compared to matched HCs. These cells express significantly lower levels of the phagocytic tyrosine kinase receptor, MerTK, and its natural ligand, growth arrest-specific 6, independently of the activation state of the cells. Increased expression of interleukin 10 following myelin uptake by healthy donor cells is lost in MDMs of patients with MS; this effect is mediated through the MerTK pathway. Treatment of MS cells with transforming growth factor β (TGFβ) restored both phagocytosis and expression deficits. CONCLUSIONS We describe a molecular mechanism that underlies a defect in myelin phagocytosis by macrophages generated from patients with MS. This abnormality involves decreased expression of MerTK and its ligands and can be rescued by treatment with TGFβ.
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Affiliation(s)
- Luke M Healy
- Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Jeong Ho Jang
- Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - So-Yoon Won
- Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Yun Hsuan Lin
- Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Hanane Touil
- Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Salman Aljarallah
- Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Amit Bar-Or
- Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Jack P Antel
- Neuroimmunology Unit (L.M.H., J.H.J., S.-Y.W., Y.H.L., H.T., S.A., A.B.-O., J.P.A.), Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada; and Multiple Sclerosis Division (A.B.-O.), Department of Neurology and Center for Neuroinflammation and Neurotherapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
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25
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Evans AL, Blackburn JWD, Taruc K, Kipp A, Dirk BS, Hunt NR, Barr SD, Dikeakos JD, Heit B. Antagonistic Coevolution of MER Tyrosine Kinase Expression and Function. Mol Biol Evol 2017; 34:1613-1628. [PMID: 28369510 DOI: 10.1093/molbev/msx102] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TYRO3, AXL, and MERTK (TAM) receptors are a family of receptor tyrosine kinases that maintain homeostasis through the clearance of apoptotic cells, and when defective, contribute to chronic inflammatory and autoimmune diseases such as atherosclerosis, multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, and Crohn's disease. In addition, certain enveloped viruses utilize TAM receptors for immune evasion and entry into host cells, with several viruses preferentially hijacking MERTK for these purposes. Despite the biological importance of TAM receptors, little is understood of their recent evolution and its impact on their function. Using evolutionary analysis of primate TAM receptor sequences, we identified strong, recent positive selection in MERTK's signal peptide and transmembrane domain that was absent from TYRO3 and AXL. Reconstruction of hominid and primate ancestral MERTK sequences revealed three nonsynonymous single nucleotide polymorphisms in the human MERTK signal peptide, with a G14C mutation resulting in a predicted non-B DNA cruciform motif, producing a significant decrease in MERTK expression with no significant effect on MERTK trafficking or half-life. Reconstruction of MERTK's transmembrane domain identified three amino acid substitutions and four amino acid insertions in humans, which led to significantly higher levels of self-clustering through the creation of a new interaction motif. This clustering counteracted the effect of the signal peptide mutations through enhancing MERTK avidity, whereas the lower MERTK expression led to reduced binding of Ebola virus-like particles. The decreased MERTK expression counterbalanced by increased avidity is consistent with antagonistic coevolution to evade viral hijacking of MERTK.
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Affiliation(s)
- Amanda L Evans
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
| | - Jack W D Blackburn
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
| | - Kyle Taruc
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
| | - Angela Kipp
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
| | - Brennan S Dirk
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
| | - Nina R Hunt
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
| | - Stephen D Barr
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
| | - Jimmy D Dikeakos
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
| | - Bryan Heit
- Department of Microbiology and Immunology and the Centre for Human Immunology, The University of Western Ontario, London, Canada
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26
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Gauci S, Hosking W, Bruck D. Narcolepsy, cataplexy, hypocretin and co-existing other health complaints: A review. COGENT MEDICINE 2017. [DOI: 10.1080/2331205x.2017.1312791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Samantha Gauci
- Psychology Discipline, College of Arts, College of Health and Biomedicine, Victoria University, P.O. Box 14428, Melbourne 8001, Australia
| | - Warwick Hosking
- Psychology Discipline, College of Arts, College of Health and Biomedicine, Victoria University, P.O. Box 14428, Melbourne 8001, Australia
| | - Dorothy Bruck
- Psychology Discipline, College of Arts, College of Health and Biomedicine, Victoria University, P.O. Box 14428, Melbourne 8001, Australia
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27
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Yin C, Kim Y, Argintaru D, Heit B. Rab17 mediates differential antigen sorting following efferocytosis and phagocytosis. Cell Death Dis 2016; 7:e2529. [PMID: 28005073 PMCID: PMC5261003 DOI: 10.1038/cddis.2016.431] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 12/29/2022]
Abstract
Macrophages engulf and destroy pathogens (phagocytosis) and apoptotic cells (efferocytosis), and can subsequently initiate adaptive immune responses by presenting antigens derived from engulfed materials. Both phagocytosis and efferocytosis share a common degradative pathway in which the target is engulfed into a membrane-bound vesicle, respectively, termed the phagosome and efferosome, where they are degraded by sequential fusion with endosomes and lysosomes. Despite this shared maturation pathway, macrophages are immunogenic following phagocytosis but not efferocytosis, indicating that differential processing or trafficking of antigens must occur. Mass spectrometry and immunofluorescence microscopy of efferosomes and phagosomes in macrophages demonstrated that efferosomes lacked the proteins required for antigen presentation and instead recruited the recycling regulator Rab17. As a result, degraded materials from efferosomes bypassed the MHC class II loading compartment via the recycling endosome - a process not observed in phagosomes. Combined, these results indicate that macrophages prevent presentation of apoptotic cell-derived antigens by preferentially trafficking efferocytosed, but not phagocytosed, materials away from the MHC class II loading compartment via the recycling endosome pathway.
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Affiliation(s)
- Charles Yin
- Department of Microbiology and Immunology and The Centre for Human Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON, Canada N6A 5C1
| | - Yohan Kim
- Department of Microbiology and Immunology and The Centre for Human Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON, Canada N6A 5C1
| | - Dean Argintaru
- Department of Microbiology and Immunology and The Centre for Human Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON, Canada N6A 5C1
| | - Bryan Heit
- Department of Microbiology and Immunology and The Centre for Human Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON, Canada N6A 5C1
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28
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The Gas6/TAM System and Multiple Sclerosis. Int J Mol Sci 2016; 17:ijms17111807. [PMID: 27801848 PMCID: PMC5133808 DOI: 10.3390/ijms17111807] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 10/22/2016] [Accepted: 10/26/2016] [Indexed: 01/25/2023] Open
Abstract
Growth arrest specific 6 (Gas6) is a multimodular circulating protein, the biological actions of which are mediated by the interaction with three transmembrane tyrosine kinase receptors: Tyro3, Axl, and MerTK, collectively named TAM. Over the last few decades, many progresses have been done in the understanding of the biological activities of this highly pleiotropic system, which plays a role in the regulation of immune response, inflammation, coagulation, cell growth, and clearance of apoptotic bodies. Recent findings have further related Gas6 and TAM receptors to neuroinflammation in general and, specifically, to multiple sclerosis (MS). In this paper, we review the biology of the Gas6/TAM system and the current evidence supporting its potential role in the pathogenesis of MS.
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