Genetics of multiple sclerosis: lessons from polygenicity

Mycobacterium paratuberculosis: A HERV Turn-On for Autoimmunity, Neurodegeneration, and Cancer?

Human endogenous retroviruses (HERVs) are remnants of ancient retroviral infections that, over millions of years, became integrated into the human genome. While normally inactive, environmental stimuli such as infections have contributed to the transcriptional reactivation of HERV-promoting pathological conditions, including the development of autoimmunity, neurodegenerative disease and cancer. What infections trigger HERV activation? Mycobacterium avium subspecies paratuberculosis (MAP) is a pluripotent driver of human disease. Aside from granulomatous diseases, Crohn's disease, sarcoidosis and Blau syndrome, MAP is associated with autoimmune disease: type one diabetes (T1D), multiple sclerosis (MS), rheumatoid arthritis (RA) and autoimmune thyroiditis. MAP is also associated with Alzheimer's disease (AD) and Parkinson's disease (PD). Autoimmune diabetes, MS and RA are the diseases with the strongest MAP/HERV association. There are several other diseases associated with HERV activation, including diseases whose epidemiology and/or pathology would prompt speculation for a causal role of MAP. These include non-solar uveal melanoma, colon cancer, glioblastoma and amyotrophic lateral sclerosis (ALS). This article further points to MAP infection as a contributor to autoimmunity, neurodegenerative disease and cancer via the un-silencing of HERV. We examine the link between the ever-increasing number of MAP-associated diseases and the MAP/HERV intersection with these diverse medical conditions, and propose treatment opportunities based upon this association.

Auto-immuno-deficiency syndromes

Autoimmune diseases constitute a broad, heterogenous group with many diverse and often overlapping symptoms. Even so, they are traditionally classified as either systemic, rheumatic diseases or organ-directed diseases. Several theories exist about autoimmune diseases, including defective self-recognition, altered self, molecular mimicry, bystander activation and epitope spreading. While there is no consensus about these theories, it is generally accepted that genetic, pre-disposing factors in combination with environmental factors can result in autoimmune disease. The relative contribution of genetic and environmental factors varies between diseases, as does the significance of individual contributing factors within related diseases. Among the genetic factors, molecules involved in antigen (Ag) recognition, processing, and presentation stand out (e.g., MHC I and II) together with molecules involved in immune signaling and regulation of cellular interactions (i.e., immuno-phenotypes). Also, various immuno-deficiencies have been linked to development of autoimmune diseases. Among the environmental factors, infections (e.g., viruses) have attracted most attention, but factors modulating the immune system have also been the subject of much research (e.g., sunlight and vitamin D). Multiple sclerosis currently stands out due to a very strong and proven association with Epstein-Barr virus infection, notably in cases of late infection and in cases of EBV-associated mononucleosis. Thus, a common picture is emerging that both systemic and organ-directed autoimmune diseases may appropriately be described as auto-immuno-deficiency syndromes (AIdeSs), a concept that emphasizes and integrates existing knowledge on the role of immuno-deficiencies and chronic infections with development of overlapping disease syndromes with variable frequencies of autoantibodies and/or autoreactive T cells. This review integrates and exemplifies current knowledge on the interplay of genetically determined immuno-phenotypes and chronic infections in the development of AIdeSs.

Revolutionizing adjuvant development: harnessing AI for next-generation cancer vaccines

With the COVID-19 pandemic, the importance of vaccines has been widely recognized and has led to increased research and development efforts. Vaccines also play a crucial role in cancer treatment by activating the immune system to target and destroy cancer cells. However, enhancing the efficacy of cancer vaccines remains a challenge. Adjuvants, which enhance the immune response to antigens and improve vaccine effectiveness, have faced limitations in recent years, resulting in few novel adjuvants being identified. The advancement of artificial intelligence (AI) technology in drug development has provided a foundation for adjuvant screening and application, leading to a diversification of adjuvants. This article reviews the significant role of tumor vaccines in basic research and clinical treatment and explores the use of AI technology to screen novel adjuvants from databases. The findings of this review offer valuable insights for the development of new adjuvants for next-generation vaccines.

New views on the complex interplay between degeneration and autoimmunity in multiple sclerosis

Multiple sclerosis (MS) is a frequently disabling neurological disorder characterized by symptoms, clinical signs and imaging abnormalities that typically fluctuate over time, affecting any level of the CNS. Prominent lymphocytic inflammation, many genetic susceptibility variants involving immune pathways, as well as potent responses of the neuroinflammatory component to immunomodulating drugs, have led to the natural conclusion that this disease is driven by a primary autoimmune process. In this Hypothesis and Theory article, we discuss emerging data that cast doubt on this assumption. After three decades of therapeutic experience, what has become clear is that potent immune modulators are highly effective at suppressing inflammatory relapses, yet exhibit very limited effects on the later progressive phase of MS. Moreover, neuropathological examination of MS tissue indicates that degeneration, CNS atrophy, and myelin loss are most prominent in the progressive stage, when lymphocytic inflammation paradoxically wanes. Finally, emerging clinical observations such as "progression independent of relapse activity" and "silent progression," now thought to take hold very early in the course, together argue that an underlying "cytodegenerative" process, likely targeting the myelinating unit, may in fact represent the most proximal step in a complex pathophysiological cascade exacerbated by an autoimmune inflammatory overlay. Parallels are drawn with more traditional neurodegenerative disorders, where a progressive proteopathy with prion-like propagation of toxic misfolded species is now known to play a key role. A potentially pivotal contribution of the Epstein-Barr virus and B cells in this process is also discussed.

Endogenous retroviruses in multiple sclerosis: A network-based etiopathogenic model

The present perspective article proposes an etiopathological model for multiple sclerosis pathogenesis and progression associated with the activation of human endogenous retroviruses. We reviewed preclinical, clinical, epidemiological, and evolutionary evidence indicating how the complex, multi-level interplay of genetic traits and environmental factors contributes to multiple sclerosis. We propose that endogenous retroviruses transactivation acts as a critical node in disease development. We also discuss the rationale for combined anti-retroviral therapy in multiple sclerosis as a disease-modifying therapeutic strategy. Finally, we propose that the immuno-pathogenic process triggered by endogenous retrovirus activation can be extended to aging and aging-related neurodegeneration. In this regard, endogenous retroviruses can be envisioned to act as epigenetic noise, favoring the proliferation of disorganized cellular subpopulations and accelerating system-specific "aging". Since inflammation and aging are two sides of the same coin (plastic dis-adaptation to external stimuli with system-specific degree of freedom), the two conditions may be epiphenomenal products of increased epigenomic entropy. Inflammation accelerates organ-specific aging, disrupting communication throughout critical systems of the body and producing symptoms. Overlapping neurological symptoms and syndromes may emerge from the activity of shared molecular networks that respond to endogenous retroviruses' reactivation.

A simplified method for relapsing-remitting multiple sclerosis detection: Insights from resting EEG signals

BACKGROUND AND OBJECTIVE

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease affecting the central nervous system, leading to various neurological symptoms. Early detection is paramount to prevent enduring damage during MS episodes. Although magnetic resonance imaging (MRI) is a common diagnostic tool, this study aims to explore the feasibility of using electroencephalography (EEG) signals for MS detection, considering their accessibility and ease of application compared to MRI.

METHODS

The study involved the analysis of EEG signals during rest from 17 MS patients and 27 healthy volunteers to investigate MS-healthy patterns. Power spectral density features (PSD) were extracted from the 32-channel EEG signals. The study employed Linear Discriminant Analysis (LDA), Support Vector Machine (SVM), Classification and Regression Trees (CART), and k-Nearest Neighbor (kNN) classifiers to identify channels with the highest accuracy. Notably, the study achieved 100% accuracy in MS detection using the "Fp1" and "Pz" channels with the LDA classifier. A statistical analysis, utilizing the independent sample t-test, was conducted to explore whether PSD features of these channels differed significantly between healthy individuals and those with MS.

RESULTS

The results of the study demonstrate that effective detection of MS can be achieved using PSD features from only two channels of the EEG signal. Specifically, the "Fp1" and "Pz" channels exhibited 100% accuracy in MS detection with the LDA classifier. The statistical analysis further explored and confirmed the significant differences in PSD features between healthy individuals and MS patients.

CONCLUSION

The study concludes that the proposed method, utilizing PSD features from specific EEG channels, offers a straightforward and efficient diagnostic approach for the effective detection of MS. The findings suggest the potential utility of EEG signals as a non-invasive and accessible alternative for MS detection, highlighting the importance of further research in this direction.

Multiple sclerosis treatment review for primary care providers

ABSTRACT

The treatment landscape for multiple sclerosis has dramatically grown in terms of available options and complexity. The various mechanisms of action and safety profiles of these new treatments necessitate that primary care providers remain current in knowledge and practice to provide high-quality care.

Establishment of the Diagnostic Signature of Ferroptosis Genes in Multiple Sclerosis

Ferroptosis is a novel form of membrane-dependent cell death that differs from other cell death modalities such as necrosis, apoptosis, and autophagy. Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system primarily affecting brain and spinal cord neurons. Although the pathogenesis of these two conditions may seem unrelated, recent studies have indicated a connection between ferroptosis and multiple sclerosis. In fact, ferroptosis plays a significant role in the development of MS, as evidenced by the presence of elevated iron levels and iron metabolism abnormalities in the brains, spinal cords, and other neurons of MS patients. These abnormalities disrupt iron homeostasis within cells, leading to the occurrence of ferroptosis. However, there is currently a lack of research on the diagnostic value of ferroptosis-related genes in multiple sclerosis. In this study, we employed bioinformatics methods to identify ferroptosis-related genes (ATM, GSK3B, HMGCR, KLF2, MAPK1, NFE2L1, NRAS, PCBP1, PIK3CA, RPL8, VDAC3) associated with the diagnosis of multiple sclerosis and constructed a diagnostic model. The results demonstrated that the diagnostic model accurately identified the patients' condition. Subsequently, subgroup analysis was performed based on the expression levels of ferroptosis-related genes, dividing patients into high and low expression groups. The results showed differences in immune function and immune cell infiltration between the two groups. Our study not only confirms the correlation between ferroptosis and multiple sclerosis but also demonstrates the diagnostic value of ferroptosis-related genes in the disease. This provides guidance for clinical practice and direction for further mechanistic research.

Immunopathogenesis of multiple sclerosis: molecular and cellular mechanisms and new immunotherapeutic approaches

BACKGROUND

Multiple sclerosis (MS) is a central nervous system (CNS) demyelinating autoimmune disease with increasing global prevalence. It predominantly affects females, especially those of European descent. The interplay between environmental factors and genetic predisposition plays a crucial role in MS etiopathogenesis.

METHODS

We searched recent relevant literature on reputable databases, which include, PubMed, Embase, Web of Science, Scopus, and ScienceDirect using the following keywords: multiple sclerosis, pathogenesis, autoimmunity, demyelination, therapy, and immunotherapy.

RESULTS

Various animal models have been employed to investigate the MS etiopathogenesis and therapeutics. Autoreactive T cells within the CNS recruit myeloid cells through chemokine expression, leading to the secretion of inflammatory cytokines driving the MS pathogenesis, resulting in demyelination, gliosis, and axonal loss. Key players include T cell lymphocytes (CD4+ and CD8+), B cells, and neutrophils. Signaling dysregulation in inflammatory pathways and the immunogenetic basis of MS are essential considerations for any successful therapy to MS. Data indicates that B cells and neutrophils also have significant roles in MS, despite the common belief that T cells are essential. High neutrophil-to-lymphocyte ratios correlate with MS severity, indicating their contribution to disease progression. Dysregulated signaling pathways further exacerbate MS progression.

CONCLUSION

MS remains incurable, but disease-modifying therapies, monoclonal antibodies, and immunomodulatory drugs offer hope for patients. Research on the immunogenetics and immunoregulatory functions of gut microbiota is continuing to provide light on possible treatment avenues. Understanding the complex interplay between genetic predisposition, environmental factors, and immune dysregulation is critical for developing effective treatments for MS.

Vitamin D receptor gene BsmI (rs1544410) polymorphism: role in multiple sclerosis and genotype-phenotype correlations

BACKGROUND

Multiple sclerosis (MS) has a complex pathophysiology which depends on many endogenous and exogenous factors. Vitamin D involvement has been largely studied in MS. The large distribution of the vitamin D receptor (VDR) in different immune cells is suggestive of an immunomodulatory role. The VDR gene polymorphisms have been proposed as potential risk factors for MS development or evolution with non-conclusive results.

METHODS AND RESULTS

We conducted a cross-sectional study including patients ≥ 18 years, with a diagnosis of relapsing remitting MS according to the McDonald Criteria and having a minimum follow-up period of one year after starting a disease modifying therapy. Two study groups were compared based on the Multiple Sclerosis Severity Scale or MSSS: "a slow progressor" group for an MSSS ≤ 5, and a "fast progressor" group for an MSSS > 5. The rs1544410 VDR gene polymorphism was studied for all patients. Eighty patients were included. The fast progressor groups had a higher EDSS at onset, a higher total number of relapses, more frequent and shorter time to secondary progression. The progression profile was not statistically different between genotypes and alleles of the VDR gene polymorphism rs1544410. The CC genotype and wild-type allele exhibited a more aggressive disease phenotype with a higher number of relapses the first year, shorter time to secondary progression and cerebral atrophy on assessment.

CONCLUSIONS

Our results suggest potential genotype-phenotype correlations for the rs1544410 VDR gene polymorphism in the disease course of MS. Future research on a larger scale is needed to confirm these findings.

The effects of intermittent fasting for patients with multiple sclerosis (MS): a systematic review

Some studies have investigated the impact of intermittent fasting (IF) for patients with multiple sclerosis (MS). We aimed to conduct a comprehensive systematic review to analyze and summarize all clinical studies concerning the effects of IF on patients with MS. We conducted an exhaustive review of information available in the Embase, Cochrane, and PubMed databases up until 1 September 2023. All clinical research relating to the impacts of IF for patients with MS were included. In total, this systematic review encompassed 5 studies, which included four RCTs and one pilot study. Each study involved was assessed of high quality. The results from these studies demonstrate that IF protocols could potentially serve as an effective dietary strategy for managing symptoms and improving the quality of life in individuals afflicted with MS. In conclusion, IF might be a potential beneficial dietary intervention for MS. However, the number of trials in this field is relatively limited. The large-scale clinical trials to investigate the effects of IF for MS are urgently needed, which may be helpful to manage this intricate neuroimmune disorder.

Systematic review registration

https://inplasy.com, identifier INPLASY2023100021.

Circular RNAs: Potential biomarkers and therapeutic targets for autoimmune diseases

The outcomes and prognosis of autoimmune diseases depend on early diagnosis and effective treatments. However, symptoms of early autoimmune diseases are often remarkably similar to many inflammatory diseases, leading to difficulty in precise diagnosis. Circular RNAs (circRNAs) belong to a novel class of endogenous RNAs, functioning as microRNA (miRNA) sponges or participating in protein coding. It has been shown in many studies that patients with autoimmune diseases have aberrant circRNA expression in liquid biopsy samples (such as plasma, saliva, and urine). Thus, circRNAs are potential biomarkers for the diagnosis and prognosis of autoimmune diseases. Moreover, overexpression and depletion of target circRNAs can be utilized as possible therapeutic approaches for treating autoimmune diseases. In this review, we summarized recent progress in the roles of circRNAs in the pathogenesis of autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and type 1 diabetes. We also discussed their potential as biomarkers and therapeutic targets.

Circular RNA in Multiple Sclerosis: Pathogenicity and Potential Biomarker Development: A Systematic Review

Multiple sclerosis (MS) is a complex autoimmune disorder of the CNS that affects millions of people worldwide. The causes of the disease remain unknown despite extensive efforts to understand it. CircRNAs are a unique class of endogenous non-coding RNA that are abundant, stable, conserved, and specifically expressed molecules, making them a promising biomarker of diseases. This review investigates the role of circRNA in MS pathogenicity and their potential as a biomarker through a comprehensive literature search conducted in 8 scientific databases. The studies found that there are differentially expressed circRNAs in MS patients compared to healthy controls (HC), and this difference is even more pronounced in different MS subtypes. Enrichment of circRNAs in linkage disequilibrium (LD) blocks that harbor MS-associated SNPs suggests that these SNPs manipulate the levels of circRNAs in the surrounding area, contributing to disease pathogenicity. While circRNA shows promise as an indicator or biomarker for MS disease pathology, further research is needed to fully explore its potential and impact on human biology.

The Role of Atypical Chemokine Receptors in Neuroinflammation and Neurodegenerative Disorders

Neuroinflammation is associated with several neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). Neuroinflammation provides protection in acute situations but results in significant damage to the nervous system if chronic. Overexpression of chemokines within the brain results in the recruitment and activation of glial and peripheral immune cells which can propagate a cascading inflammatory response, resulting in neurodegeneration and the onset of neurodegenerative disorders. Recent work has identified the role of atypical chemokine receptors (ACKRs) in neurodegenerative conditions. ACKRs are seven-transmembrane domain receptors that do not follow canonical G protein signaling, but regulate inflammatory responses by modulating chemokine abundance, location, and availability. This review summarizes what is known about the four ACKRs and three putative ACKRs within the brain, highlighting their known expression and discussing the current understanding of each ACKR in the context of neurodegeneration. The ability of ACKRs to alter levels of chemokines makes them an appealing therapeutic target for neurodegenerative conditions. However, further work is necessary to understand the expression of several ACKRs within the neuroimmune system and the effectiveness of targeted drug therapies in the prevention and treatment of neurodegenerative conditions.

Could NCOA5 a novel candidate gene for multiple sclerosis susceptibility?

BACKGROUND

Multiple sclerosis (MS) is an inflammatory immune-mediated demyelinating disease that causes a challenging and disabling condition. Environmental and genetic factors play a role in appearing the state of the disease. Recent studies have shown that nuclear cofactor genes may play a role in the pathogenesis of MS. NCOA5 is a nuclear receptor coactivator independent of AF2 that modulates ERa-mediated transcription. This gene is involved in the pathogenesis of diseases such as psoriasis, Behcet's disease, and cancer.

METHODS AND RESULTS

We investigated the relationship between the rs2903908 polymorphism of the NCOA5 gene and MS among 157 unrelated MS patients and 160 healthy controls by RT-PCR. The frequencies of the CC, CT, and TT genotypes were 19.87%, 37.82%, and 42.31%, respectively, for the MS group and 5.63%, 43.75%, and 50.62%, respectively, for the control group. The CC genotype and the C allele were found to be significantly higher in the patient group (the p values were 0.0002 and 0.003, respectively).

CONCLUSIONS

The fact that the CC genotype was found to be significantly higher in the patient group compared to the control group (p = 0.0002) and that it had a statistically significantly higher OR value (OR, 95% CI = 4.16, 1.91-9.05) suggests that the C allele may recessively predispose to MS for this polymorphism. These results suggest for the first time that the NCOA5 gene may have an effect on the occurrence of MS through different molecular pathways, which are discussed in the manuscript.

Genetic risk score in multiple sclerosis is associated with unique gut microbiome

Multiple sclerosis (MS) is a complex autoimmune disease in which both the roles of genetic susceptibility and environmental/microbial factors have been investigated. More than 200 genetic susceptibility variants have been identified along with the dysbiosis of gut microbiota, both independently have been shown to be associated with MS. We hypothesize that MS patients harboring genetic susceptibility variants along with gut microbiome dysbiosis are at a greater risk of exhibiting the disease. We investigated the genetic risk score for MS in conjunction with gut microbiota in the same cohort of 117 relapsing remitting MS (RRMS) and 26 healthy controls. DNA samples were genotyped using Illumina's Infinium Immuno array-24 v2 chip followed by calculating genetic risk score and the microbiota was determined by sequencing the V4 hypervariable region of the 16S rRNA gene. We identified two clusters of MS patients, Cluster A and B, both having a higher genetic risk score than the control group. However, the MS cases in cluster B not only had a higher genetic risk score but also showed a distinct gut microbiome than that of cluster A. Interestingly, cluster A which included both healthy control and MS cases had similar gut microbiome composition. This could be due to (i) the non-active state of the disease in that group of MS patients at the time of fecal sample collection and/or (ii) the restoration of the gut microbiome post disease modifying therapy to treat the MS. Our study showed that there seems to be an association between genetic risk score and gut microbiome dysbiosis in triggering the disease in a small cohort of MS patients. The MS Cluster A who have a higher genetic risk score but microbiome profile similar to that of healthy controls could be due to the remitting phase of the disease or due to the effect of disease modifying therapies.

Integrated Analysis of Immune Infiltration and Hub Pyroptosis-Related Genes for Multiple Sclerosis

Purpose

Studies on overall immune infiltration and pyroptosis in patients with multiple sclerosis (MS) are limited. This study explored immune cell infiltration and pyroptosis in MS using bioinformatics and experimental validation.

Methods

The GSE131282 and GSE135511 microarray datasets including brain autopsy tissues from controls and MS patients were downloaded for bioinformatic analysis. The gene expression-based deconvolution method, CIBERSORT, was used to determine immune infiltration. Differentially expressed genes (DEGs) and functional enrichments were analyzed. We then extracted pyroptosis-related genes (PRGs) from the DEGs by using machine learning strategies. Their diagnostic ability for MS was evaluated in both the training set (GSE131282 dataset) and validation set (GSE135511 dataset). In addition, messenger RNA (mRNA) expression of PRGs was validated using quantitative real-time polymerase chain reaction (qRT-PCR) in cortical tissue from an experimental autoimmune encephalomyelitis (EAE) model of MS. Moreover, the functional enrichment pathways of each hub PRG were estimated. Finally, co-expressed competitive endogenous RNA (ceRNA) networks of PRGs in MS were constructed.

Results

Among the infiltrating cells, naive CD4+ T cells (P=0.006), resting NK cells (P=0.002), activated mast cells (P=0.022), and neutrophils (P=0.002) were significantly higher in patients with MS than in controls. The DEGs of MS were screened. Analysis of enrichment pathways showed that the pathways of transcriptional regulatory mechanisms and ion channels associating with pyroptosis. Four PRGs genes CASP4, PLCG1, CASP9 and NLRC4 were identified. They were validated in both the GSE135511 dataset and the EAE model by using qRT-PCR. CASP4 and NLRC4 were ultimately identified as stable hub PRGs for MS. Single-gene Gene Set Enrichment Analysis showed that they mainly participated in biosynthesis, metabolism, and organism resistance. ceRNA networks containing CASP4 and NLRC4 were constructed.

Conclusion

MS was associated with immune infiltration. CASP4 and NLRC4 were key biomarkers of pyroptosis in MS.

Vitamin D Receptor Gene Polymorphism Predicts the Outcome of Multidisciplinary Rehabilitation in Multiple Sclerosis Patients

Better knowledge about the possible role of genetic factors in modulating the response to multiple sclerosis (MS) treatment, including rehabilitation, known to promote neural plasticity, could improve the standard of care for this disease. Vitamin D receptor (VDR) gene polymorphisms are associated with MS risk, probably because of the role played by vitamin D in regulating inflammatory and reparative processes. The aim of this study was to evaluate the association of the most important functional VDR SNPs (TaqI (T/C), ApaI (A/C), and FokI (C/T)) with functional outcome in MS patients undergoing multidisciplinary inpatient rehabilitation (MDR) treatment, in order to determine whether genetic profiling might be useful to identify subjects with a higher chance of recovery. To this end, 249 MS inpatients with a diagnosis of either progressive (pMS; n = 155) or relapsing remitting (RRMS; n = 94) disease who underwent MDR treatment (average duration = 5.1 weeks) were genotyped for VDR SNPs by real-time allelic discrimination. The rehabilitation outcome was assessed using the modified Barthel Index (mBI), Expanded Disability Status Scale (EDSS), and pain numerical rating scores (NRS) at the beginning and the end of MDR treatment. A positive correlation was observed in RRMS patients between the VDR TaqI major allele (TT) and mBI increase (i.e., better functional recovery), as assessed by the linear and logistic regression analysis adjusted for gender, age, disease duration, time of hospitalization, HLA-DRB1*15.01 positivity, and number of rehabilitative interventions (Beta = 6.35; p = 0.0002). The VDR-1 TaqI, ApaI, FokI: TCC haplotype was also associated with mBI increase in RRMS patients (Beta = 3.24; p = 0.007), whereas the VDR-2: CAC haplotype was correlated with a lower mBI increase (Beta = -2.18 p = 0.04) compared with the other haplotypes. VDR TaqI major allele (TT), as well as the VDR-1 TaqI, ApaI, FokI: TCC haplotype could be associated with a better rehabilitation outcome in RRMS patients.

The Role of Gut Microbiome in the Pathogenesis of Multiple Sclerosis and Related Disorders

Multiple sclerosis (MS) is a chronic, progressive neuroinflammatory disease with a complex pathophysiological background. A variety of diverse factors have been attributed to the propagation of inflammation and neurodegeneration in MS, mainly genetic, immunological, and environmental factors such as vitamin D deficiency, infections, or hormonal disbalance. Recently, the importance of the gut-brain axis for the development of many neurological conditions, including stroke, movement disorders, and neuroinflammatory disorders, has been postulated. The purpose of our paper was to summarize current evidence confirming the role of the gut microbiome in the pathophysiology of MS and related disorders, such as neuromyelitis optica spectrum disorder (NMO-SD). For this aim, we conducted a systematic review of the literature listed in the following databases: Medline, Pubmed, and Scopus, and were able to identify several studies demonstrating the involvement of the gut microbiome in the pathophysiology of MS and NMO-SD. It seems that the most relevant bacteria for the pathophysiology of MS are those belonging to Pseudomonas, Mycoplasma, Haemophilus, Blautia, Dorea, Faecalibacterium, Methanobrevibacter, Akkermansia, and Desulfovibrionaceae genera, while Clostridium perfringens and Streptoccocus have been demonstrated to play a role in the pathophysiology of NMO-SD. Following this line of evidence, there is also some preliminary data supporting the use of probiotics or other agents affecting the microbiome that could potentially have a beneficial effect on MS/NMO-SD symptoms and prognosis. The topic of the gut microbiome in the pathophysiology of MS is therefore relevant since it could be used as a biomarker of disease development and progression as well as a potential disease-modifying therapy.

Mycobacterium avium subsp. paratuberculosis Antigens Elicit a Strong IgG4 Response in Patients with Multiple Sclerosis and Exacerbate Experimental Autoimmune Encephalomyelitis

Neuroinflammation can be triggered by microbial products disrupting immune regulation. In this study, we investigated the levels of IgG1, IgG2, IgG3, and IgG4 subclasses against the heat shock protein (HSP)70_533-545 peptide and lipopentapeptide (MAP_Lp5) derived from Mycobacterium avium subsp. paratuberculosis (MAP) in the blood samples of Japanese and Italian individuals with relapsing remitting multiple sclerosis (MS). Additionally, we examined the impact of this peptide on MOG-induced experimental autoimmune encephalomyelitis (EAE). A total of 130 Japanese and 130 Italian subjects were retrospectively analyzed using the indirect ELISA method. Furthermore, a group of C57BL/6J mice received immunization with the MAP_HSP70_533-545 peptide two weeks prior to the active induction of MOG_35-55 EAE. The results revealed a significantly robust antibody response against MAP_HSP70_533-545 in serum of both Japanese and Italian MS patients compared to their respective control groups. Moreover, heightened levels of serum IgG4 antibodies specific to MAP antigens were correlated with the severity of the disease. Additionally, EAE mice that were immunized with MAP_HSP70_533-545 peptide exhibited more severe disease symptoms and increased reactivity of MOG_35-55-specific T-cell compared to untreated mice. These findings provide evidence suggesting a potential link between MAP and the development or exacerbation of MS, particularly in a subgroup of MS patients with elevated serum IgG4 levels.

Molecular and neuroimmune pharmacology of S1P receptor modulators and other disease-modifying therapies for multiple sclerosis

Multiple sclerosis (MS) is a neurological, immune-mediated demyelinating disease that affects people in the prime of life. Environmental, infectious, and genetic factors have been implicated in its etiology, although a definitive cause has yet to be determined. Nevertheless, multiple disease-modifying therapies (DMTs: including interferons, glatiramer acetate, fumarates, cladribine, teriflunomide, fingolimod, siponimod, ozanimod, ponesimod, and monoclonal antibodies targeting ITGA4, CD20, and CD52) have been developed and approved for the treatment of MS. All the DMTs approved to date target immunomodulation as their mechanism of action (MOA); however, the direct effects of some DMTs on the central nervous system (CNS), particularly sphingosine 1-phosphate (S1P) receptor (S1PR) modulators, implicate a parallel MOA that may also reduce neurodegenerative sequelae. This review summarizes the currently approved DMTs for the treatment of MS and provides details and recent advances in the molecular pharmacology, immunopharmacology, and neuropharmacology of S1PR modulators, with a special focus on the CNS-oriented, astrocyte-centric MOA of fingolimod.

Neuroimmune, clinical and treatment challenges in multiple sclerosis-related psychoses

In recent years, epidemiological and genetic studies have shown an association between autoimmune diseases and psychosis. The question arises whether patients with schizophrenia are more likely to develop multiple sclerosis (MS) later in life. It is well known that the immune system plays an important role in the etiopathogenesis of both disorders. Immune disturbances may be similar or very different in terms of different types of immune responses, disturbed myelination, and/or immunogenetic predispositions. A psychotic symptom may be a consequence of the MS diagnosis itself or a separate entity. In this review article, we discussed the timing of onset of psychotic symptoms and MS and whether the use of corticosteroids as therapy for acute relapses in MS is unfairly neglected in patients with psychiatric comorbidities. In addition, we discussed that the anti-inflammatory potential of antipsychotics could be useful and should be considered, especially in the treatment of psychosis that coexists with MS. Autoimmune disorders could precipitate psychotic symptoms, and in this context, autoimmune psychosis must be considered as a persistent symptomatology that requires continuous and specific treatment.

Celiac Disease Is a Risk Factor for Mature T and NK Cell Lymphoma: A Mendelian Randomization Study

Celiac disease (CeD) is an immune-mediated disorder triggered by gluten ingestion that damages the small intestine. Although CeD has been associated with a higher risk for cancer, the role of CeD as a risk factor for specific malignancies, such as enteropathy-associated T-cell lymphoma (EATL), remains controversial. Using two-sample Mendelian randomization (2SMR) methods and the summarized results of large genome-wide association studies from public repositories, we addressed the causal relationship between CeD and eight different malignancies. Eleven non-HLA SNPs were selected as instrumental variables (IVs), and causality estimates were obtained using four 2SMR methods: random-effects inverse variance-weighted, weighted median estimation, MR-Egger regression, and MR pleiotropy residual sum and outlier (MR-PRESSO). We identified a significant causal relationship between CeD and mature T/NK cell lymphomas. Under a multivariate Mendelian randomization model, we observed that the causal effect of CeD was not dependent on other known lymphoma risk factors. We found that the most instrumental IV was located in the TAGAP locus, suggesting that aberrant T cell activation might be relevant in the T/NK cell malignization process. Our findings provide new insights into the connection between immune imbalance and the development of severe comorbidities, such as EATL, in patients with CeD.

Epstein-Barr virus as a cause of multiple sclerosis: opportunities for prevention and therapy

Multiple sclerosis is a chronic inflammatory disease of the CNS that results from the interplay between heritable and environmental factors. Mounting evidence from different fields of research supports the pivotal role of the Epstein-Barr virus (EBV) in the development of multiple sclerosis. However, translating this knowledge into clinically actionable information requires a better understanding of the mechanisms linking EBV to pathophysiology. Ongoing research is trying to clarify whether EBV causes neuroinflammation via autoimmunity or antiviral immunity, and if the interaction of EBV with genetic susceptibility to multiple sclerosis can explain why a ubiquitous virus promotes immune dysfunction in susceptible individuals. If EBV also has a role in driving disease activity, the characterisation of this role will help diagnosis, prognosis, and treatment in people with multiple sclerosis. Ongoing clinical trials targeting EBV and new anti-EBV vaccines provide hope for future treatments and preventive interventions.

Pregnancy Is Associated with Impaired Transcription of Human Endogenous Retroviruses and of TRIM28 and SETDB1, Particularly in Mothers Affected by Multiple Sclerosis

Accumulating evidence highlights the pathogenetic role of human endogenous retroviruses (HERVs) in eliciting and maintaining multiple sclerosis (MS). Epigenetic mechanisms, such as those regulated by TRIM 28 and SETDB1, are implicated in HERV activation and in neuroinflammatory disorders, including MS. Pregnancy markedly improves the course of MS, but no study explored the expressions of HERVs and of TRIM28 and SETDB1 during gestation. Using a polymerase chain reaction real-time Taqman amplification assay, we assessed and compared the transcriptional levels of pol genes of HERV-H, HERV-K, HERV-W; of env genes of Syncytin (SYN)1, SYN2, and multiple sclerosis associated retrovirus (MSRV); and of TRIM28 and SETDB1 in peripheral blood and placenta from 20 mothers affected by MS; from 27 healthy mothers, in cord blood from their neonates; and in blood from healthy women of child-bearing age. The HERV mRNA levels were significantly lower in pregnant than in nonpregnant women. Expressions of all HERVs were downregulated in the chorion and in the decidua basalis of MS mothers compared to healthy mothers. The former also showed lower mRNA levels of HERV-K-pol and of SYN1, SYN2, and MSRV in peripheral blood. Significantly lower expressions of TRIM28 and SETDB1 also emerged in pregnant vs. nonpregnant women and in blood, chorion, and decidua of mothers with MS vs. healthy mothers. In contrast, HERV and TRIM28/SETDB1 expressions were comparable between their neonates. These results show that gestation is characterized by impaired expressions of HERVs and TRIM28/SETDB1, particularly in mothers with MS. Given the beneficial effects of pregnancy on MS and the wealth of data suggesting the putative contribution of HERVs and epigenetic processes in the pathogenesis of the disease, our findings may further support innovative therapeutic interventions to block HERV activation and to control aberrant epigenetic pathways in MS-affected patients.

Role of DAMPs and cell death in autoimmune diseases: the example of multiple sclerosis

Multiple sclerosis is a chronic neuroinflammatory demyelinating disease of the central nervous system (CNS) of unknown etiology and still incompletely clarified pathogenesis. The disease is generally considered a disorder resulting from a complex interplay between environmental risk factors and predisposing causal genetic variants. To examine the etiopathogenesis of the disease, two complementary pre-clinical models are currently discussed: the "outside-in" model proposing a peripherally elicited inflammatory/autoimmune attack against degraded myelin as the cause of the disease, and the "inside-out" paradigm implying a primary cytodegenerative process of cells in the CNS that triggers secondary reactive inflammatory/autoimmune responses against myelin debris. In this review, the integrating pathogenetic role of damage-associated molecular patterns (DAMPs) in these two scenario models is examined by focusing on the origin and sources of these molecules, which are known to promote neuroinflammation and, via activation of pattern recognition receptor-bearing antigen-presenting cells, drive and shape autoimmune responses. In particular, environmental factors are discussed that are conceptually defined as agents which produce endogenous DAMPs via induction of regulated cell death (RCD) or act themselves as exogenous DAMPs. Indeed, in the field of autoimmune diseases, including multiple sclerosis, recent research has focused on environmental triggers that cause secondary events in terms of subroutines of RCD, which have been identified as prolific sources of DAMPs. Finally, a model of a DAMP-driven positive feed-forward loop of chronic inflammatory demyelinating processes is proposed, aimed at reconciling the competing "inside-out" and "outside-in" paradigms.

Hypothesis of a potential BrainBiota and its relation to CNS autoimmune inflammation

Infectious agents have been long considered to play a role in the pathogenesis of neurological diseases as part of the interaction between genetic susceptibility and the environment. The role of bacteria in CNS autoimmunity has also been highlighted by changes in the diversity of gut microbiota in patients with neurological diseases such as Parkinson's disease, Alzheimer disease and multiple sclerosis, emphasizing the role of the gut-brain axis. We discuss the hypothesis of a brain microbiota, the BrainBiota: bacteria living in symbiosis with brain cells. Existence of various bacteria in the human brain is suggested by morphological evidence, presence of bacterial proteins, metabolites, transcripts and mucosal-associated invariant T cells. Based on our data, we discuss the hypothesis that these bacteria are an integral part of brain development and immune tolerance as well as directly linked to the gut microbiome. We further suggest that changes of the BrainBiota during brain diseases may be the consequence or cause of the chronic inflammation similarly to the gut microbiota.