Molecular Mechanisms of Immunosenescene and Inflammaging: Relevance to the Immunopathogenesis and Treatment of Multiple Sclerosis

DNA Methylation in the Anti-Mullerian Hormone Gene and the Risk of Disease Activity in Multiple Sclerosis

OBJECTIVE

Multiple sclerosis (MS) has a complex pathobiology, with genetic and environmental factors being crucial players. Understanding the mechanisms underlying heterogeneity in disease activity is crucial for tailored treatment. We explored the impact of DNA methylation, a key mechanism in the genetics-environment interplay, on disease activity in MS.

METHODS

Peripheral immune methylome profiling using Illumina Infinium MethylationEPIC BeadChips was conducted on 249 untreated relapsing-remitting MS patients, sampled at the start of disease-modifying treatment (DMT). A differential methylation analysis compared patients with evidence of disease activity (EDA) to those with no evidence of disease activity (NEDA) over 2 years from DMT start. Utilizing causal inference testing (CIT) and Mendelian randomization (MR), we sought to elucidate the relationships between DNA methylation, gene expression, genetic variation, and disease activity.

RESULTS

Four differentially methylated regions (DMRs) were identified between EDA and NEDA. Examining the influence of single nucleotide polymorphisms (SNPs), 923 variants were found to account for the observed differences in the 4 DMRs. Importantly, 3 out of the 923 SNPs, affecting DNA methylation in a DMR linked to the anti-Mullerian hormone (AMH) gene, were associated with disease activity risk in an independent cohort of 1,408 MS patients. CIT and MR demonstrated that DNA methylation in AMH acts as a mediator for the genetic risk of disease activity.

INTERPRETATION

This study uncovered a novel molecular pathway implicating the interaction between DNA methylation and genetic variation in the risk of disease activity in MS, emphasizing the role of sex hormones, particularly the AMH, in MS pathobiology. ANN NEUROL 2024;96:289-301.

Macrophage iron dyshomeostasis promotes aging-related renal fibrosis

Renal aging, marked by the accumulation of senescent cells and chronic low-grade inflammation, leads to renal interstitial fibrosis and impaired function. In this study, we investigate the role of macrophages, a key regulator of inflammation, in renal aging by analyzing kidney single-cell RNA sequencing data of C57BL/6J mice from 8 weeks to 24 months. Our findings elucidate the dynamic changes in the proportion of kidney cell types during renal aging and reveal that increased macrophage infiltration contributes to chronic low-grade inflammation, with these macrophages exhibiting senescence and activation of ferroptosis signaling. CellChat analysis indicates enhanced communications between macrophages and tubular cells during aging. Suppressing ferroptosis alleviates macrophage-mediated tubular partial epithelial-mesenchymal transition in vitro, thereby mitigating the expression of fibrosis-related genes. Using SCENIC analysis, we infer Stat1 as a key age-related transcription factor promoting iron dyshomeostasis and ferroptosis in macrophages by regulating the expression of Pcbp1, an iron chaperone protein that inhibits ferroptosis. Furthermore, through virtual screening and molecular docking from a library of anti-aging compounds, we construct a docking model targeting Pcbp1, which indicates that the natural small molecule compound Rutin can suppress macrophage senescence and ferroptosis by preserving Pcbp1. In summary, our study underscores the crucial role of macrophage iron dyshomeostasis and ferroptosis in renal aging. Our results also suggest Pcbp1 as an intervention target in aging-related renal fibrosis and highlight Rutin as a potential therapeutic agent in mitigating age-related renal chronic low-grade inflammation and fibrosis.

Effects of immune exhaustion and senescence of innate immunity in autoimmune disorders

Innate immune system activation is crucial in the inflammatory response, but uncontrolled activation can lead to autoimmune diseases. Cellular exhaustion and senescence are two processes that contribute to innate immune tolerance breakdown. Exhausted immune cells are unable to respond adequately to specific antigens or stimuli, while senescent cells have impaired DNA replication and metabolic changes. These processes can impair immune system function and disrupt homeostasis, leading to the emergence of autoimmunity. However, the influence of innate immune exhaustion and senescence on autoimmune disorders is not well understood. This review aims to describe the current findings on the role of innate immune exhaustion and senescence in autoimmunity, focusing on the cellular and molecular changes involved in each process. Specifically, the article explores the markers and pathways associated with immune exhaustion, such as PD-1 and TIM-3, and senescence, including Β-galactosidase (β-GAL), lamin B1, and p16ink4a, and their impact on autoimmune diseases, namely type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and immune-mediated myopathies. Understanding the mechanisms underlying innate immune exhaustion and senescence in autoimmunity may provide insights for the development of novel therapeutic strategies.

Glycoprotein Acetyls Is a Novel Biomarker Predicting Cardiovascular Complications in Rheumatoid Arthritis

The relationship between rheumatoid arthritis (RA) and early onset atherosclerosis is well depicted, each with an important inflammatory component. Glycoprotein acetyls (GlycA), a novel biomarker of inflammation, may play a role in the manifestation of these two inflammatory conditions. The present study examined a potential mediating role of GlycA within the RA-atherosclerosis relationship to determine whether it accounts for the excess risk of cardiovascular disease over that posed by lipid risk factors. The UK Biobank dataset was acquired to establish associations among RA, atherosclerosis, GlycA, and major lipid factors: total cholesterol (TC), high- and low-density lipoprotein (HDL, LDL) cholesterol, and triglycerides (TGs). Genome-wide association study summary statistics were collected from various resources to perform genetic analyses. Causality among variables was tested using Mendelian Randomization (MR) analysis. Genes of interest were identified using colocalization analysis and gene enrichment analysis. MR results appeared to indicate that the genetic relationship between GlycA and RA and also between RA and atherosclerosis was explained by horizontal pleiotropy (p-value = 0.001 and <0.001, respectively), while GlycA may causally predict atherosclerosis (p-value = 0.017). Colocalization analysis revealed several functionally relevant genes shared between GlycA and all the variables assessed. Two loci were apparent in all relationships tested and included the HLA region as well as SLC22A1. GlycA appears to mediate the RA-atherosclerosis relationship through several possible pathways. GlycA, although pleiotropically related to RA, appears to causally predict atherosclerosis. Thus, GlycA is suggested as a significant factor in the etiology of atherosclerosis development in RA.

Managing multiple sclerosis in individuals aged 55 and above: a comprehensive review

Multiple Sclerosis (MS) management in individuals aged 55 and above presents unique challenges due to the complex interaction between aging, comorbidities, immunosenescence, and MS pathophysiology. This comprehensive review explores the evolving landscape of MS in older adults, including the increased incidence and prevalence of MS in this age group, the shift in disease phenotypes from relapsing-remitting to progressive forms, and the presence of multimorbidity and polypharmacy. We aim to provide an updated review of the available evidence of disease-modifying treatments (DMTs) in older patients, including the efficacy and safety of existing therapies, emerging treatments such as Bruton tyrosine kinase (BTKs) inhibitors and those targeting remyelination and neuroprotection, and the critical decisions surrounding the initiation, de-escalation, and discontinuation of DMTs. Non-pharmacologic approaches, including physical therapy, neuromodulation therapies, cognitive rehabilitation, and psychotherapy, are also examined for their role in holistic care. The importance of MS Care Units and advance care planning are explored as a cornerstone in providing patient-centric care, ensuring alignment with patient preferences in the disease trajectory. Finally, the review emphasizes the need for personalized management and continuous monitoring of MS patients, alongside advocating for inclusive study designs in clinical research to improve the management of this growing patient demographic.

Immunosenescence and Cytomegalovirus: Exploring Their Connection in the Context of Aging, Health, and Disease

Aging induces numerous physiological alterations, with immunosenescence emerging as a pivotal factor. This phenomenon has attracted both researchers and clinicians, prompting profound questions about its implications for health and disease. Among the contributing factors, one intriguing actor in this complex interplay is human cytomegalovirus (CMV), a member of the herpesvirus family. Latent CMV infection exerts a profound influence on the aging immune system, potentially contributing to age-related diseases. This review delves into the intricate relationship between immunosenescence and CMV, revealing how chronic viral infection impacts the aging immune landscape. We explore the mechanisms through which CMV can impact both the composition and functionality of immune cell populations and induce shifts in inflammatory profiles with aging. Moreover, we examine the potential role of CMV in pathologies such as cardiovascular diseases, cancer, neurodegenerative disorders, COVID-19, and Long COVID. This review underlines the importance of understanding the complex interplay between immunosenescence and CMV. It offers insights into the pathophysiology of aging and age-associated diseases, as well as COVID-19 outcomes among the elderly. By unraveling the connections between immunosenescence and CMV, we gain a deeper understanding of aging's remarkable journey and the profound role that viral infections play in transforming the human immune system.

Microglia activation in periplaque white matter in multiple sclerosis depends on age and lesion type, but does not correlate with oligodendroglial loss

Multiple sclerosis (MS) is the most frequent inflammatory and demyelinating disease of the CNS. The disease course in MS is highly variable and driven by a combination of relapse-driven disease activity and relapse-independent disease progression. The formation of new focal demyelinating lesions is associated with clinical relapses; however, the pathological mechanisms driving disease progression are less well understood. Current concepts suggest that ongoing focal and diffuse inflammation within the CNS in combination with an age-associated failure of compensatory and repair mechanisms contribute to disease progression. The aim of our study was to characterize the diffuse microglia activation in periplaque white matter (PPWM) of MS patients, to identify factors modulating its extent and to determine its potential correlation with loss or preservation of oligodendrocytes. We analyzed microglial and oligodendroglial numbers in PPWM in a cohort of 96 tissue blocks from 32 MS patients containing 100 lesions as well as a control cohort (n = 37). Microglia activation in PPWM was dependent on patient age, proximity to lesion, lesion type, and to a lesser degree on sex. Oligodendrocyte numbers were decreased in PPWM; however, increased microglia densities did not correlate with lower oligodendroglial cell counts, indicating that diffuse microglia activation is not sufficient to drive oligodendroglial loss in PPWM. In summary, our findings support the notion of the close relationship between focal and diffuse inflammation in MS and that age is an important modulator of MS pathology.

Biological aging in multiple sclerosis

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.

Cerebrospinal fluid oligoclonal bands in Chinese patients with multiple sclerosis: the prevalence and its association with clinical features

Background

Cerebrospinal fluid oligoclonal band (CSF-OCB) is an established biomarker in diagnosing multiple sclerosis (MS), however, there are no nationwide data on CSF-OCB prevalence and its diagnostic performance in Chinese MS patients, especially in the virtue of common standard operation procedure (SOP).

Methods

With a consensus SOP and the same isoelectric focusing system, we conducted a nationwide multi-center study on OCB status in consecutively, and recruited 483 MS patients and 880 non-MS patients, including neuro-inflammatory diseases (NID, n = 595) and non-inflammatory neurological diseases (NIND, n=285). Using a standardized case report form (CRF) to collect the clinical, radiological, immunological, and CSF data, we explored the association of CSF-OCB positivity with patient characters and the diagnostic performance of CSF-OCB in Chinese MS patients. Prospective source data collection, and retrospective data acquisition and statistical data analysis were used.

Findings

369 (76.4%) MS patients were OCB-positive, while 109 NID patients (18.3%) and 6 NIND patients (2.1%) were OCB-positive, respectively. Time from symptom onset to diagnosis was significantly shorter in OCB-positive than that in OCB-negative MS patients (13.2 vs 23.7 months, P=0.020). The prevalence of CSF-OCB in Chinese MS patients was significantly higher in high-latitude regions (41°-50°N)(P=0.016), and at high altitudes (>1000m)(P=0.025). The diagnostic performance of CSF-OCB differentiating MS from non-MS patients yielded a sensitivity of 76%, a specificity of 87%.

Interpretation

The nationwide prevalence of CSF-OCB was 76.4% in Chinese MS patients, and demonstrated a good diagnostic performance in differentiating MS from other CNS diseases. The CSF-OCB prevalence showed a correlation with high latitude and altitude in Chinese MS patients.

From aging to long COVID: exploring the convergence of immunosenescence, inflammaging, and autoimmunity

The process of aging is accompanied by a dynamic restructuring of the immune response, a phenomenon known as immunosenescence. This mini-review navigates through the complex landscape of age-associated immune changes, chronic inflammation, age-related autoimmune tendencies, and their potential links with immunopathology of Long COVID. Immunosenescence serves as an introductory departure point, elucidating alterations in immune cell profiles and their functional dynamics, changes in T-cell receptor signaling, cytokine network dysregulation, and compromised regulatory T-cell function. Subsequent scrutiny of chronic inflammation, or "inflammaging," highlights its roles in age-related autoimmune susceptibilities and its potential as a mediator of the immune perturbations observed in Long COVID patients. The introduction of epigenetic facets further amplifies the potential interconnections. In this compact review, we consider the dynamic interactions between immunosenescence, inflammation, and autoimmunity. We aim to explore the multifaceted relationships that link these processes and shed light on the underlying mechanisms that drive their interconnectedness. With a focus on understanding the immunological changes in the context of aging, we seek to provide insights into how immunosenescence and inflammation contribute to the emergence and progression of autoimmune disorders in the elderly and may serve as potential mediator for Long COVID disturbances.

Immunosenescence and multiple sclerosis: inflammaging for prognosis and therapeutic consideration

Aging is associated with a progressive decline of innate and adaptive immune responses, called immunosenescence. This phenomenon links to different multiple sclerosis (MS) disease courses among different age groups. While clinical relapse and active demyelination are mainly related to the altered adaptive immunity, including invasion of T- and B-lymphocytes, impairment of innate immune cell (e.g., microglia, astrocyte) function is the main contributor to disability progression and neurodegeneration. Most patients with MS manifest the relapsing-remitting phenotype at a younger age, while progressive phenotypes are mainly seen in older patients. Current disease-modifying therapies (DMTs) primarily targeting adaptive immunity are less efficacious in older patients, suggesting that immunosenescence plays a role in treatment response. This review summarizes the recent immune mechanistic studies regarding immunosenescence in patients with MS and discusses the clinical implications of these findings.

Therapeutic Plasma Exchange and Multiple Sclerosis Dysregulations: Focus on the Removal of Pathogenic Circulatory Factors and Altering Nerve Growth Factor and Sphingosine-1-Phosphate Plasma Levels

Multiple sclerosis (MS) is predominantly an immune-mediated disease of the central nervous system (CNS) of unknown etiology with a possible genetic predisposition and effect of certain environmental factors. It is generally accepted that the disease begins with an autoimmune inflammatory reaction targeting oligodendrocytes followed by a rapid depletion of their regenerative capacity with subsequent permanent neurodegenerative changes and disability. Recent research highlights the central role of B lymphocytes and the corresponding IgG and IgM autoantibodies in newly forming MS lesions. Thus, their removal along with the modulation of certain bioactive molecules to improve neuroprotection using therapeutic plasma exchange (TPE) becomes of utmost importance. Recently, it has been proposed to determine the levels and precise effects of both beneficial and harmful components in the serum of MS patients undergoing TPE to serve as markers for appropriate TPE protocols. In this review we discuss some relevant examples, focusing on the removal of pathogenic circulating factors and altering the plasma levels of nerve growth factor and sphingosine-1-phosphate by TPE. Altered plasma levels of the reviewed molecular compounds in response to TPE reflect a successful reduction of the pro-inflammatory burden at the expense of an increase in anti-inflammatory potential in the circulatory and CNS compartments.

Immune-Stimulating Potential of Lacticaseibacillus rhamnosus LM1019 in RAW 264.7 Cells and Immunosuppressed Mice Induced by Cyclophosphamide

Probiotics, including Lacticaseibacillus rhamnosus (L. rhamnosus), have gained recognition for their potential health benefits, such as enhancing immune function, maintaining gut health, and improving nutrient absorption. This study investigated the effectiveness of L. rhamnosus LM1019 (LM1019) in enhancing immune function. In RAW 264.7 cells, LM1019 demonstrated dose-dependent immune stimulation by increasing nitric oxide production, gene expression of proinflammatory cytokines, and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). These effects were mediated through the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) translocation without inducing cytotoxicity. Furthermore, orally administered LM1019 was evaluated in immunosuppressed mice induced by cyclophosphamide (CTX). High-dose administration of LM1019 significantly increased the subpopulations of lymphocytes, specifically helper T cells (CD4+), as well as two subtypes of natural killer (NK) cells, namely, IFN-γ+ and granzyme B+ NK cells. Additionally, LM1019 at a high dose led to elevated levels of proinflammatory cytokines, including IFN-γ and IL-12, compared to CTX-treated mice. These findings highlight the potential of LM1019 in enhancing the immune system. The study contributes to the growing body of research on the beneficial effects of probiotics on immune function.

Treatment of older patients with multiple sclerosis: Results of an International Delphi Survey

Background

People over age 50-55 have historically been excluded from randomized clinical trials for multiple sclerosis (MS). However, more than half of those living with an MS diagnosis are over 55.

Objective

Explore the unique considerations of treating older people with MS (PwMS) using an iterative and structured Delphi-based assessment to gather expert opinions.

Methods

Eight MS neurologists with an interest in older PwMS developed a 2-round survey. Survey respondents were qualified neurologists with ≥3 years' experience, personally responsible for treatment decisions, and treating ≥20 patients per month, of whom ≥10% were ≥50 years old. Consensus was defined as ≥75% agreement on questions with categorical responses or as a mean score ≥4 on questions with numerical responses.

Results

In Survey 1, 224 neurologists responded; 180 of these completed Survey 2. Limited consensus was reached with varying levels of agreement on several topics including identification and assessment of older patients; factors relating to treatment decisions including immunosenescence and comorbidities; considerations for high-efficacy treatments; de-escalation or discontinuation of treatment; effects of COVID-19; and unmet needs for treating this population.

Conclusion

The results of this Delphi process highlight the need for targeted studies to create guidance for the care of older PwMS.

Remyelination in animal models of multiple sclerosis: finding the elusive grail of regeneration

Remyelination biology and the therapeutic potential of restoring myelin sheaths to prevent neurodegeneration and disability in multiple sclerosis (MS) has made considerable gains over the past decade with many regeneration strategies undergoing tested in MS clinical trials. Animal models used to investigate oligodendroglial responses and regeneration of myelin vary considerably in the mechanism of demyelination, involvement of inflammatory cells, neurodegeneration and capacity for remyelination. The investigation of remyelination in the context of aging and an inflammatory environment are of considerable interest for the potential translation to progressive multiple sclerosis. Here we review how remyelination is assessed in mouse models of demyelination, differences and advantages of these models, therapeutic strategies that have emerged and current pro-remyelination clinical trials.

Aging in multiple sclerosis: from childhood to old age, etiopathogenesis, and unmet needs: a narrative review

Multiple sclerosis (MS) primarily affects adult females. However, in the last decades, rising incidence and prevalence have been observed for demographic extremes, such as pediatric-onset MS (POMS; occurring before 18 years of age) and late-onset MS (corresponding to an onset above 50 years). These categories show peculiar clinical-pathogenetic characteristics, aging processes and disease courses, therapeutic options, and unmet needs. Nonetheless, several open questions are still pending. POMS patients display an important contribution of multiple genetic and environmental factors such as EBV, while in LOMS, hormonal changes and pollution may represent disease triggers. In both categories, immunosenescence emerges as a pathogenic driver of the disease, particularly for LOMS. In both populations, patient and caregiver engagement are essential from the diagnosis communication to early treatment of disease-modifying therapy (DMTs), which in the elderly population appears more complex and less proven in terms of efficacy and safety. Digital technologies (e.g., exergames and e-training) have recently emerged with promising results, particularly in treating and following motor and cognitive deficits. However, this offer seems more feasible for POMS, being LOMS less familiar with digital technology. In this narrative review, we discuss how the aging process influences the pathogenesis, disease course, and therapeutic options of both POMS and LOMS. Finally, we evaluate the impact of new digital communication tools, which greatly interest the current and future management of POMS and LOMS patients.

Confirmation of CD19+ B-Lymphocyte Depletion Prior to Intake of the Second Dose of Ocrelizumab in Multiple Sclerosis Patients

The aim of the retrospective study was to compare the immunophenotyping of T-lymphocytes, B-lymphocytes, and natural killer cells before the administration of the first and the second dose of ocrelizumab in 22 patients with multiple sclerosis in a three-year period (2019-2021) at the Department of Neurology of the University Hospital of Split. The values of cell immunophenotyping and protein electrophoresis, as well as laboratory parameters, were investigated. There was no significant decrease in serum albumin and globulins before the second dose of ocrelizumab (p > 0,05). A decrease in the number of T-lymphocytes before administration of the second dose of ocrelizumab was observed, but without statistical significance (p = 0.274). Significant depletion occurred in median CD19+ B-lymphocytes (p < 0.001) before the intake of the second dose of ocrelizumab confirming the primary action of ocrelizumab on the B cell lineage.

Endothelial Dysfunction and Chronic Inflammation: The Cornerstones of Vascular Alterations in Age-Related Diseases

Vascular diseases of the elderly are a topic of enormous interest in clinical practice, as they have great epidemiological significance and lead to ever-increasing healthcare expenditures. The mechanisms underlying these pathologies have been increasingly characterized over the years. It has emerged that endothelial dysfunction and chronic inflammation play a diriment role among the most relevant pathophysiological mechanisms. As one can easily imagine, various processes occur during aging, and several pathways undergo irreversible alterations that can promote the decline and aberrations that trigger the diseases above. Endothelial dysfunction and aging of circulating and resident cells are the main characteristics of the aged organism; they represent the framework within which an enormous array of molecular abnormalities occur and contribute to accelerating and perpetuating the decline of organs and tissues. Recognizing and detailing each of these dysfunctional pathways is helpful for therapeutic purposes, as it allows one to hypothesize the possibility of tailoring interventions to the damaged mechanism and hypothetically limiting the cascade of events that drive the onset of these diseases. With this paper, we have reviewed the scientific literature, analysing the pathophysiological basis of the vascular diseases of the elderly and pausing to reflect on attempts to interrupt the vicious cycle that connotes the diseases of aging, laying the groundwork for therapeutic reasoning and expanding the field of scientific research by moving from a solid foundation.

Long-duration head-down tilt bed rest confirms the relevance of the neutrophil to lymphocyte ratio and suggests coupling it with the platelet to lymphocyte ratio to monitor the immune health of astronauts

The identification of safe and easily-determined-inflight biomarkers to monitor the immune system of astronauts is mandatory to ensure their well-being and the success of the missions. In this report, we evaluated the relevance of two biomarkers whose determination could be easily implemented in a spacecraft in the near future by using bedridden volunteers as a ground-based model of the microgravity of spaceflight. Our data confirm the relevance of the neutrophil to lymphocyte ratio (NLR) and suggest platelet to lymphocyte ratio (PLR) monitoring to assess long-lasting immune diseases. We recommend coupling these ratios to other biomarkers, such as the quantification of cytokines and viral load measurements, to efficiently detect immune dysfunction, determine when countermeasures should be applied to promote immune recovery, prevent the development of disease, and track responses to treatment.

Selective Upregulation of SIRT1 Expression in Retinal Ganglion Cells by AAV-Mediated Gene Delivery Increases Neuronal Cell Survival and Alleviates Axon Demyelination Associated with Optic Neuritis

Optic neuritis (ON), the most common ocular manifestation of multiple sclerosis, is an autoimmune inflammatory demyelinating disease also characterized by degeneration of retinal ganglion cells (RGCs) and their axons, which commonly leads to visual impairment despite attempted treatments. Although ON disease etiology is not known, changes in the redox system and exacerbated optic nerve inflammation play a major role in the pathogenesis of the disease. Silent information regulator 1 (sirtuin-1/SIRT1) is a ubiquitously expressed NAD+-dependent deacetylase, which functions to reduce/prevent both oxidative stress and inflammation in various tissues. Non-specific upregulation of SIRT1 by pharmacologic and genetic approaches attenuates RGC loss in experimental ON. Herein, we hypothesized that targeted expression of SIRT1 selectively in RGCs using an adeno-associated virus (AAV) vector as a delivery vehicle is an effective approach to reducing neurodegeneration and preserving vision in ON. We tested this hypothesis through intravitreal injection of AAV7m8.SNCG.SIRT1, an AAV2-derived vector optimized for highly efficient SIRT1 transgene transfer and protein expression into RGCs in mice with experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis that recapitulates optic neuritis RGC loss and axon demyelination. Our data show that EAE mice injected with a control vehicle exhibit progressive alteration of visual function reflected by decreasing optokinetic response (OKR) scores, whereas comparatively, AAV7m8.SNCG.SIRT1-injected EAE mice maintain higher OKR scores, suggesting that SIRT1 reduces the visual deficit imparted by EAE. Consistent with this, RGC survival determined by immunolabeling is increased and axon demyelination is decreased in the AAV7m8.SNCG.SIRT1 RGC-injected group of EAE mice compared to the mouse EAE counterpart injected with a vehicle or with control vector AAV7m8.SNCG.eGFP. However, immune cell infiltration of the optic nerve is not significantly different among all EAE groups of mice injected with either vehicle or AAV7m8.SNCG.SIRT1. We conclude that despite minimally affecting the inflammatory response in the optic nerve, AAV7m8-mediated SIRT1 transfer into RGCs has a neuroprotective potential against RGC loss, axon demyelination and vison deficits associated with EAE. Together, these data suggest that SIRT1 exerts direct effects on RGC survival and function.