T cell responses to COVID-19 infection and vaccination in patients with multiple sclerosis receiving disease-modifying therapy.

BACKGROUND: Multiple sclerosis (MS) is a neurological disorder marked by accumulating immune-mediated damage to the central nervous system. The dysregulated immune system in MS combined with immune effects of disease-modifying therapies (DMTs) used in MS treatment could alter responses to infections, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). Most of the literature on immune response to SARS-CoV-2 infection and COVID-19 vaccination, in both the general population and patients with MS on DMTs, has focused on humoral immunity. However, immune response to COVID-19 involves multiple lines of defense, including T cells. OBJECTIVE AND METHODS: We review innate and adaptive immunity to COVID-19 and expand on the role of T cells in mediating protective immunity against SARS-CoV-2 infection and in responses to COVID-19 vaccination in MS. RESULTS: Innate, humoral, and T cell immune responses combat COVID-19 and generate protective immunity. Assays detecting cytokine expression by T cells show an association between SARS-CoV-2-specific T cell responses and milder/asymptomatic COVID-19 and protective immune memory. CONCLUSION: Studies of COVID-19 immunity in people with MS on DMTs should ideally include comprehensive assessment of innate, humoral, and T cell responses.

Gut Microbiome in Progressive Multiple Sclerosis.

OBJECTIVE: This study was undertaken to investigate the gut microbiome in progressive multiple sclerosis (MS) and how it relates to clinical disease. METHODS: We sequenced the microbiota from healthy controls and relapsing-remitting MS (RRMS) and progressive MS patients and correlated the levels of bacteria with clinical features of disease, including Expanded Disability Status Scale (EDSS), quality of life, and brain magnetic resonance imaging lesions/atrophy. We colonized mice with MS-derived Akkermansia and induced experimental autoimmune encephalomyelitis (EAE). RESULTS: Microbiota ß-diversity differed between MS patients and controls but did not differ between RRMS and progressive MS or differ based on disease-modifying therapies. Disease status had the greatest effect on the microbiome ß-diversity, followed by body mass index, race, and sex. In both progressive MS and RRMS, we found increased Clostridium bolteae, Ruthenibacterium lactatiformans, and Akkermansia and decreased Blautia wexlerae, Dorea formicigenerans, and Erysipelotrichaceae CCMM. Unique to progressive MS, we found elevated Enterobacteriaceae and Clostridium g24 FCEY and decreased Blautia and Agathobaculum. Several Clostridium species were associated with higher EDSS and fatigue scores. Contrary to the view that elevated Akkermansia in MS has a detrimental role, we found that Akkermansia was linked to lower disability, suggesting a beneficial role. Consistent with this, we found that Akkermansia isolated from MS patients ameliorated EAE, which was linked to a reduction in RORγt+ and IL-17-producing γδ T cells. INTERPRETATION: Whereas some microbiota alterations are shared in relapsing and progressive MS, we identified unique bacteria associated with progressive MS and clinical measures of disease. Furthermore, elevated Akkermansia in MS may be a compensatory beneficial response in the MS microbiome. ANN NEUROL 2021;89:1195-1211.

A probiotic modulates the microbiome and immunity in multiple sclerosis.

OBJECTIVE: Effect of a probiotic on the gut microbiome and peripheral immune function in healthy controls and relapsing-remitting multiple sclerosis (MS) patients. METHODS: MS patients (N = 9) and controls (N = 13) were orally administered a probiotic containing Lactobacillus, Bifidobacterium, and Streptococcus twice-daily for two months. Blood and stool specimens were collected at baseline, after completion of the 2-month treatment, and 3 months after discontinuation of therapy. Frozen peripheral blood mononuclear cells (PBMCs) were used for immune cell profiling. Stool samples were used for 16S rRNA profiling and metabolomics. RESULTS: Probiotic administration increased the abundance of several taxa known to be depleted in MS such as Lactobacillus. We found that probiotic use decreased the abundance of taxa previously associated with dysbiosis in MS, including Akkermansia and Blautia. Predictive metagenomic analysis revealed a decrease in the abundance of several KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways associated with altered gut microbiota function in MS patients, such as methane metabolism, following probiotic supplementation. At the immune level, probiotic administration induced an anti-inflammatory peripheral immune response characterized by decreased frequency of inflammatory monocytes, decreased mean fluorescence intensity (MFI) of CD80 on classical monocytes, as well as decreased human leukocyte antigen (HLA) D related MFI on dendritic cells. Probiotic administration was also associated with decreased expression of MS risk allele HLA-DQA1 in controls. Probiotic-induced increase in abundance of Lactobacillus and Bifidobacterium was associated with decreased expression of MS risk allele HLA.DPB1 in controls. INTERPRETATION: Our results suggest that probiotics could have a synergistic effect with current MS therapies. Ann Neurol 2018.

Investigation of probiotics in multiple sclerosis.

None of the disease-modifying therapies (DMTs) currently being used for the management of multiple sclerosis (MS) are 100% effective. In addition, side effects associated with the use of these DMTs have limited the practice of combination therapy. Hence, there is a need for safe immunomodulatory agents to fine-tune the management of MS. The gut microbiome plays an important role in autoimmunity, and several studies have reported alterations in the gut microbiome of MS patients. Studies in animal model of MS have identified members of the gut commensal microflora that exacerbate or ameliorate neuroinflammation. Probiotics represent an oral, non-toxic immunomodulatory agent that could be used in combination with current MS therapy. We designed a pilot study to investigate the effect of VSL3 on the gut microbiome and peripheral immune system function in healthy controls and MS patients. VSL3 administration was associated with increased abundance of many taxa with enriched taxa predominated by Lactobacillus, Streptococcus, and Bifidobacterium species. At the immune level, VSL3 administration induced an anti-inflammatory peripheral immune response characterized by decreased frequency of intermediate monocytes (CD14highCD16low), decreased mean fluorescence intensity (MFI) of CD80 on classical monocytes as well as decreased human leukocyte antigen-antigen D related (HLA-DR) MFI on dendritic cells.

Oral vancomycin treatment suppresses gut trypsin activity and preserves intestinal barrier function during EAE.

Studies have reported increased intestinal permeability in multiple sclerosis (MS) patients and its mouse model experimental autoimmune encephalomyelitis (EAE). However, the mechanisms driving increased intestinal permeability that in turn exacerbate neuroinflammation during EAE remain unclear. Here we showed that vancomycin preserved the integrity of the intestinal barrier, while also suppressing gut trypsin activity, enhancing the relative abundance of specific Lactobacilli and ameliorating disease during EAE. Furthermore, Lactobacilli enriched in the gut of vancomycin-treated EAE mice at day 3 post immunization negatively correlated with gut trypsin activity and EAE severity. In untreated EAE mice, we observed increased intestinal permeability and increased intestinal protease activated receptor 2 (PAR2) expression at day 3 post immunization. Prior studies have shown that trypsin increases intestinal permeability by activating PAR2. Our results suggest that the interaction between intestinal PAR2 and trypsin may be a key modulator of intestinal permeability and disease severity during EAE.

S-nitrosylated GAPDH initiates apoptotic cell death by nuclear translocation following Siah1 binding.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) influences cytotoxicity, translocating to the nucleus during apoptosis. Here we report a signalling pathway in which nitric oxide (NO) generation that follows apoptotic stimulation elicits S-nitrosylation of GAPDH, which triggers binding to Siah1 (an E3 ubiquitin ligase), nuclear translocation and apoptosis. S-nitrosylation of GAPDH augments its binding to Siah1, whose nuclear localization signal mediates translocation of GAPDH. GAPDH stabilizes Siah1, facilitating its degradation of nuclear proteins. Activation of macrophages by endotoxin and of neurons by glutamate elicits GAPDH-Siah1 binding, nuclear translocation and apoptosis, which are prevented by NO deletion. The NO-S-nitrosylation-GAPDH-Siah1 cascade may represent an important molecular mechanism of cytotoxicity.

Mining the microbiota to identify gut commensals modulating neuroinflammation in a mouse model of multiple sclerosis.

BACKGROUND: The gut microbiome plays an important role in autoimmunity including multiple sclerosis and its mouse model called experimental autoimmune encephalomyelitis (EAE). Prior studies have demonstrated that the multiple sclerosis gut microbiota can contribute to disease, hence making it a potential therapeutic target. In addition, antibiotic treatment has been shown to ameliorate disease in the EAE mouse model of multiple sclerosis. Yet, to this date, the mechanisms mediating these antibiotic effects are not understood. Furthermore, there is no consensus on the gut-derived bacterial strains that drive neuroinflammation in multiple sclerosis. RESULTS: Here, we characterized the gut microbiome of untreated and vancomycin-treated EAE mice over time to identify bacteria with neuroimmunomodulatory potential. We observed alterations in the gut microbiota composition following EAE induction. We found that vancomycin treatment ameliorates EAE, and that this protective effect is mediated via the microbiota. Notably, we observed increased abundance of bacteria known to be strong inducers of regulatory T cells, including members of Clostridium clusters XIVa and XVIII in vancomycin-treated mice during the presymptomatic phase of EAE, as well as at disease peak. We identified 50 bacterial taxa that correlate with EAE severity. Interestingly, several of these taxa exist in the human gut, and some of them have been implicated in multiple sclerosis including Anaerotruncus colihominis, a butyrate producer, which had a positive correlation with disease severity. We found that Anaerotruncus colihominis ameliorates EAE, and this is associated with induction of RORγt+ regulatory T cells in the mesenteric lymph nodes. CONCLUSIONS: We identified vancomycin as a potent modulator of the gut-brain axis by promoting the proliferation of bacterial species that induce regulatory T cells. In addition, our findings reveal 50 gut commensals as regulator of the gut-brain axis that can be used to further characterize pathogenic and beneficial host-microbiota interactions in multiple sclerosis patients. Our findings suggest that elevated Anaerotruncus colihominis in multiple sclerosis patients may represent a protective mechanism associated with recovery from the disease. Video Abstract.

Latent-period stool proteomic assay of multiple sclerosis model indicates protective capacity of host-expressed protease inhibitors.

Diseases are often diagnosed once overt symptoms arise, ignoring the prior latent period when effective prevention may be possible. Experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis, exhibits such disease latency, but the molecular processes underlying this asymptomatic period remain poorly characterized. Gut microbes also influence EAE severity, yet their impact on the latent period remains unknown. Here, we show the latent period between immunization and EAE's overt symptom onset is characterized by distinct host responses as measured by stool proteomics. In particular, we found a transient increase in protease inhibitors that inversely correlated with disease severity. Vancomycin administration attenuated both EAE symptoms and protease inhibitor induction potentially by decreasing immune system reactivity, supporting a subset of the microbiota's role in modulating the host's latent period response. These results strengthen previous evidence of proteases and their inhibitors in EAE and highlight the utility stool-omics for revealing complex, dynamic biology.

Oral Administration of miR-30d from Feces of MS Patients Suppresses MS-like Symptoms in Mice by Expanding Akkermansia muciniphila.

Fecal transfer from healthy donors is being explored as a microbiome modality. MicroRNAs (miRNAs) have been found to affect the microbiome. Multiple sclerosis (MS) patients have been shown to have an altered gut microbiome. Here, we unexpectedly found that transfer of feces harvested at peak disease from the experimental autoimmune encephalomyelitis (EAE) model of MS ameliorates disease in recipients in a miRNA-dependent manner. Specifically, we show that miR-30d is enriched in the feces of peak EAE and untreated MS patients. Synthetic miR-30d given orally ameliorates EAE through expansion of regulatory T cells (Tregs). Mechanistically, miR-30d regulates the expression of a lactase in Akkermansia muciniphila, which increases Akkermansia abundance in the gut. The expanded Akkermansia in turn increases Tregs to suppress EAE symptoms. Our findings report the mechanistic underpinnings of a miRNA-microbiome axis and suggest that the feces of diseased subjects might be enriched with miRNAs with therapeutic properties.