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Fettig NM, Pu A, Osborne LC, Gommerman JL. The influence of aging and the microbiome in multiple sclerosis and other neurologic diseases. Immunol Rev 2024; 325:166-189. [PMID: 38890777 DOI: 10.1111/imr.13361] [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] [Indexed: 06/20/2024]
Abstract
The human gut microbiome is well-recognized as a key player in maintaining health. However, it is a dynamic entity that changes across the lifespan. How the microbial changes that occur in later decades of life shape host health or impact age-associated inflammatory neurological diseases such as multiple sclerosis (MS) is still unclear. Current understanding of the aging gut microbiome is largely limited to cross-sectional observational studies. Moreover, studies in humans are limited by confounding host-intrinsic and extrinsic factors that are not easily disentangled from aging. This review provides a comprehensive summary of existing literature on the aging gut microbiome and its known relationships with neurological diseases, with a specific focus on MS. We will also discuss preclinical animal models and human studies that shed light on the complex microbiota-host interactions that have the potential to influence disease pathology and progression in aging individuals. Lastly, we propose potential avenues of investigation to deconvolute features of an aging microbiota that contribute to disease, or alternatively promote health in advanced age.
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Affiliation(s)
- Naomi M Fettig
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Annie Pu
- Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Lisa C Osborne
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
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2
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Woo MS, Engler JB, Friese MA. The neuropathobiology of multiple sclerosis. Nat Rev Neurosci 2024; 25:493-513. [PMID: 38789516 DOI: 10.1038/s41583-024-00823-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2024] [Indexed: 05/26/2024]
Abstract
Chronic low-grade inflammation and neuronal deregulation are two components of a smoldering disease activity that drives the progression of disability in people with multiple sclerosis (MS). Although several therapies exist to dampen the acute inflammation that drives MS relapses, therapeutic options to halt chronic disability progression are a major unmet clinical need. The development of such therapies is hindered by our limited understanding of the neuron-intrinsic determinants of resilience or vulnerability to inflammation. In this Review, we provide a neuron-centric overview of recent advances in deciphering neuronal response patterns that drive the pathology of MS. We describe the inflammatory CNS environment that initiates neurotoxicity by imposing ion imbalance, excitotoxicity and oxidative stress, and by direct neuro-immune interactions, which collectively lead to mitochondrial dysfunction and epigenetic dysregulation. The neuronal demise is further amplified by breakdown of neuronal transport, accumulation of cytosolic proteins and activation of cell death pathways. Continuous neuronal damage perpetuates CNS inflammation by activating surrounding glia cells and by directly exerting toxicity on neighbouring neurons. Further, we explore strategies to overcome neuronal deregulation in MS and compile a selection of neuronal actuators shown to impact neurodegeneration in preclinical studies. We conclude by discussing the therapeutic potential of targeting such neuronal actuators in MS, including some that have already been tested in interventional clinical trials.
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Affiliation(s)
- Marcel S Woo
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Broder Engler
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Manuel A Friese
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
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3
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Gommerman JL. What Jane Jacobs has taught me about neuroimmunology. Nat Immunol 2024; 25:381. [PMID: 38429453 DOI: 10.1038/s41590-024-01764-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Affiliation(s)
- Jennifer L Gommerman
- Department of Immunology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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4
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Zhang Y, Atkinson J, Burd CE, Graves J, Segal BM. Biological aging in multiple sclerosis. Mult Scler 2023; 29:1701-1708. [PMID: 37877740 PMCID: PMC10843499 DOI: 10.1177/13524585231204122] [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] [Indexed: 10/26/2023]
Abstract
Multiple sclerosis (MS) is most likely to adopt a progressive clinical course during middle age or beyond, and the number of older adults with MS is steadily increasing. Developing new strategies to manage progressive forms of MS, which do not respond to currently available disease-modifying therapies (DMTs), will require a deeper understanding of the mechanisms by which biological aging interacts with pathogenic pathways to propel disability accumulation. In experimental autoimmune encephalomyelitis (EAE), a widely used preclinical mouse model of MS, middle-aged animals experience a more severe and protracted clinical course than their younger counterparts. This exacerbated disease course is accompanied by persistent neuroinflammation. Clinical studies of age-related biomarkers, such as telomere length, senescence markers, and DNA methylation, suggest that biological aging is accelerated in people with MS compared with age- and sex-matched healthy controls. Furthermore, distinguishing biological age from chronological may afford more precision in determining aging effects in MS. Here we review the current literature on aging biology and its impact on MS pathogenesis. Future research on this topic may lead to the development of novel biomarkers and senotherapy agents that slow neurological decline in people with progressive MS by targeting relevant aging-related pathways.
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Affiliation(s)
- Yinan Zhang
- Department of Neurology, The Ohio State University Wexner
Medical Center, Columbus, OH
| | - Jeffrey Atkinson
- Department of Neurology, The Ohio State University Wexner
Medical Center, Columbus, OH
| | - Christin E. Burd
- Departments of Molecular Genetics, Cancer Biology and
Genetics, The Ohio State University, Columbus, OH
| | - Jennifer Graves
- Department of Neurosciences, University of California San
Diego, San Diego, CA
| | - Benjamin M. Segal
- Department of Neurology, The Ohio State University Wexner
Medical Center, Columbus, OH
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Macaron G, Larochelle C, Arbour N, Galmard M, Girard JM, Prat A, Duquette P. Impact of aging on treatment considerations for multiple sclerosis patients. Front Neurol 2023; 14:1197212. [PMID: 37483447 PMCID: PMC10361071 DOI: 10.3389/fneur.2023.1197212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/18/2023] [Indexed: 07/25/2023] Open
Abstract
With a rapidly aging global population and improvement of outcomes with newer multiple sclerosis (MS)-specific disease-modifying therapies (DMTs), the epidemiology of MS has shifted to an older than previously described population, with a peak prevalence of the disease seen in the 55-65 years age group. Changes in the pathophysiology of MS appear to be age-dependent. Several studies have identified a consistent phase of disability worsening around the fifth decade of life. The latter appears to be independent of prior disease duration and inflammatory activity and concomitant to pathological changes from acute focal active demyelination to chronic smoldering plaques, slow-expanding lesions, and compartmentalized inflammation within the central nervous system (CNS). On the other hand, decreased CNS tissue reserve and poorer remyelinating capacity with aging lead to loss of relapse recovery potential. Aging with MS may imply longer exposure to DMTs, although treatment efficacy in patients >55 years has not been evaluated in pivotal randomized controlled trials and appears to decrease with age. Older individuals are more prone to adverse effects of DMTs, an important aspect of treatment individualization. Aging with MS also implies a higher global burden of comorbid illnesses that contribute to overall impairments and represent a crucial confounder in interpreting clinical worsening. Discontinuation of DMTs after age 55, when no evidence of clinical or radiological activity is detected, is currently under the spotlight. In this review, we will discuss the impact of aging on MS pathobiology, the effect of comorbidities and other confounders on clinical worsening, and focus on current therapeutic considerations in this age group.
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Affiliation(s)
- Gabrielle Macaron
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Faculté de Médecine, Université Saint-Joseph de Beyrouth, Beirut, Lebanon
| | - Catherine Larochelle
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Nathalie Arbour
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Manon Galmard
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Jean Marc Girard
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Alexandre Prat
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Pierre Duquette
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
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Zuo M, Fettig NM, Bernier LP, Pössnecker E, Spring S, Pu A, Ma XI, Lee DS, Ward LA, Sharma A, Kuhle J, Sled JG, Pröbstel AK, MacVicar BA, Osborne LC, Gommerman JL, Ramaglia V. Age-dependent gray matter demyelination is associated with leptomeningeal neutrophil accumulation. JCI Insight 2022; 7:e158144. [PMID: 35536649 PMCID: PMC9309059 DOI: 10.1172/jci.insight.158144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/04/2022] [Indexed: 11/21/2022] Open
Abstract
People living with multiple sclerosis (MS) experience episodic CNS white matter lesions instigated by autoreactive T cells. With age, patients with MS show evidence of gray matter demyelination and experience devastating nonremitting symptomology. What drives progression is unclear and studying this has been hampered by the lack of suitable animal models. Here, we show that passive experimental autoimmune encephalomyelitis (EAE) induced by an adoptive transfer of young Th17 cells induced a nonremitting clinical phenotype that was associated with persistent leptomeningeal inflammation and cortical pathology in old, but not young, SJL/J mice. Although the quantity and quality of T cells did not differ in the brains of old versus young EAE mice, an increase in neutrophils and a decrease in B cells were observed in the brains of old mice. Neutrophils were also found in the leptomeninges of a subset of progressive MS patient brains that showed evidence of leptomeningeal inflammation and subpial cortical demyelination. Taken together, our data show that while Th17 cells initiate CNS inflammation, subsequent clinical symptoms and gray matter pathology are dictated by age and associated with other immune cells, such as neutrophils.
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Affiliation(s)
- Michelle Zuo
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Naomi M. Fettig
- Department of Microbiology and Immunology and Life Sciences Institute, and
| | - Louis-Philippe Bernier
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Elisabeth Pössnecker
- Multiple Sclerosis Center & Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), Departments of Neurology, Biomedicine, and Clinical Research, University Hospital and University of Basel, Basel, Switzerland
| | - Shoshana Spring
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Annie Pu
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Xianjie I. Ma
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Dennis S.W. Lee
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Lesley A. Ward
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Anshu Sharma
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Jens Kuhle
- Multiple Sclerosis Center & Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), Departments of Neurology, Biomedicine, and Clinical Research, University Hospital and University of Basel, Basel, Switzerland
| | - John G. Sled
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Anne-Katrin Pröbstel
- Multiple Sclerosis Center & Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), Departments of Neurology, Biomedicine, and Clinical Research, University Hospital and University of Basel, Basel, Switzerland
| | - Brian A. MacVicar
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lisa C. Osborne
- Department of Microbiology and Immunology and Life Sciences Institute, and
| | | | - Valeria Ramaglia
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
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7
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Age-related changes in multiple sclerosis and experimental autoimmune encephalomyelitis. Semin Immunol 2022; 59:101631. [PMID: 35752572 DOI: 10.1016/j.smim.2022.101631] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 06/03/2022] [Accepted: 06/13/2022] [Indexed: 01/15/2023]
Abstract
A better understanding of the pathological mechanisms that drive neurodegeneration in people living with multiple sclerosis (MS) is needed to design effective therapies to treat and/or prevent disease progression. We propose that CNS-intrinsic inflammation and re-modelling of the sub-arachnoid space of the leptomeninges sets the stage for neurodegeneration from the earliest stages of MS. While neurodegenerative processes are clinically silent early in disease, ageing results in neurodegenerative changes that become clinically manifest as progressive disability. Here we review pathological correlates of MS disease progression, highlight emerging mouse models that mimic key progressive changes in MS, and provide new perspectives on therapeutic approaches to protect against MS-associated neurodegeneration.
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