Variant of EOMES Associated with Increasing Risk in Chinese Patients with Relapsing-remitting Multiple Sclerosis

[Multiple sclerosis in the Republic of Bashkortostan: population-specific genetic predictors and the results of a 20-year clinical follow-up study]

OBJECTIVE

Identification of a complex of genetic predictors of multiple sclerosis (MS) based on previously obtained results in genome-wide association studies of disease markers (GWAS markers) in a population of MS patients and healthy individuals of the Republic of Bashkortostan (Russian Federation) using polygenic detection.

MATERIAL AND METHODS

The total study group consisted of 2048 people (641 patients with MS and 1407 healthy individuals) who permanently resided in the Republic of Bashkortostan and belonged to the Bashkir (n=325), Russian (n=772) or Tatar (n=951) nationalities. The analysis of association between MS and polymorphisms previously associated with the disease according to GWAS data was performed. Of the 641 MS patients, 247 were the subject of a 20-year prospective clinical follow-up.

RESULTS

The C6orf10 rs3129934*T allele was most significantly associated with MS in Russians (OR=2.00, P=5.85·10-5) and Tatars (OR=2.38, P=8.61·10-7). An increased MS risk in Russians was also associated with the EOMES rs11129295*T (OR=1.56, P=0.007) and IL7R rs1494558*I (OR=1.61, P=0.003) alleles. Meta-analysis confirmed the association of the C6orf10 rs3129934*T, EOMES rs11129295*T and IL7R rs1494558*I alleles with MS in the total group, as well as revealed associations of the INAVA rs7522462*G, IL7R rs10624573*I, CD6 rs17824933*G, GPC5 rs9523762*A and GPR65 rs2119704*C alleles with the disease. Using polygenic analysis, we identified a complex predictor C6orf10 rs3129934*C + INAVA rs7522462*G + CD6 rs17824933*C with a pronounced protective effect against MS in the total group (OR=0.34, PFDR=2.65·10-7).

CONCLUSION

We reproduced the association of eight polymorphisms (C6orf10 rs3129934, INAVA rs7522462, IL7R rs10624573, EOMES rs11129295, GPR65 rs2119704, GPC5 rs9523762, CD6 rs17824933 and CD58 rs2300747) with MS, previously identified in GWAS in European populations. Whole exome or genome sequencing may help to reveal the mechanisms underlying the pathogenesis of MS in populations of the Russian Federation.

Multilocus evaluation of genetic predictors of multiple sclerosis

BACKGROUND

Genome-wide association studies identified numerous susceptibility loci for multiple sclerosis in populations of European ancestry, but the associations are not always reproducible in other populations due to admixture and different linkage disequilibrium patterns obscuring true association signals.

OBJECTIVE

Our aim was to identify genetic predictors of multiple sclerosis in three ethnically homogenous populations from the Volga-Ural region of Russian Federation.

METHODS

In the largest to date study of multiple sclerosis in Russian population, involving 2048 participants from the Republic of Bashkortostan, Russian Federation (641 patients with multiple sclerosis and 1407 unaffected individuals), we performed replication analysis of previously identified genome-wide signals for multiple sclerosis. Associations were tested using logistic regression analysis under additive genetic model adjusted for sex. Meta-analysis of the study results in three populations was performed under fixed effects and random effects models.

RESULTS

We demonstrate the association with multiple sclerosis of the five variants (INAVA rs7522462, EOMES rs11129295, C6orf10 rs3129934, CD86 rs9282641, and GPR65 rs2119704). The strongest association (OR = 2.16, CI:1.85-2.74, P = 2.53x10^-13) was detected for rs3129934 polymorphism in the major histocompatibility region. Multilocus analysis has revealed 322 and 27 allelic patterns associated with multiple sclerosis in women and men, respectively. In women, the highest risk of MS was conferred by C6orf10 rs3129934*T/T + STAT3 rs744166*T combination (OR = 11.87), in men - by C6orf10 rs3129934*T + EOMES rs11129295*C + RPS6KB1 rs180515*C combination (OR = 3.25).

CONCLUSION

We confirm five associations with multiple sclerosis previously reported in genome-wide scans in Europeans in three ethnic groups from the Volga-Ural region of Russia.

Genetics and functional genomics of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease with genetic predisposition. Over the last decade, genome-wide association studies with increasing sample size led to the discovery of robustly associated genetic variants at an exponential rate. More than 200 genetic loci have been associated with MS susceptibility and almost half of its heritability can be accounted for. However, many challenges and unknowns remain. Definitive studies of disease progression and endophenotypes are yet to be performed, whereas the majority of the identified MS variants are not yet functionally characterized. Despite these shortcomings, the unraveling of MS genetics has opened up a new chapter on our understanding MS causal mechanisms.

Involvement of cytotoxic Eomes-expressing CD4+ T cells in secondary progressive multiple sclerosis

Multiple sclerosis (MS), a putative autoimmune disease of the central nervous system (CNS), commonly presents as relapsing-remitting MS (RRMS), characterized by recurrent episodes of peripheral disabling symptoms resulting from inflammatory CNS damage. Many RRMS patients transition to a chronic disease course with progressive neurological dysfunctions (secondary progressive MS, SPMS), with the progression rate varying between patients and over time. SPMS pathogenesis is now linked to immune-cell-mediated processes, although the mechanisms driving SPMS transition and progression remain elusive, and SPMS lacks biomarkers and effective treatments. We report the crucial involvement of cytotoxic CD4⁺ T cells expressing Eomes (Eomes⁺ Th cells) in SPMS pathogenesis-a Th cell subset previously identified in a mouse model of late/chronic autoimmune CNS inflammation. Few Eomes⁺ Th cells circulate in RRMS patient peripheral blood (n = 44), primary progressive MS (PPMS) patients (n = 25), or healthy controls (n = 42), but Eomes⁺ Th cells were significantly increased in SPMS (n = 105, P < 0.0001). Strikingly, lymphocytes isolated from SPMS autopsy brain samples revealed CD4⁺ T cells infiltrating CNS that coexpressed Eomes and the cytotoxic molecule granzyme B. In particular, the Eomes⁺ Th cell levels were increased in SPMS patients in progressive disease phases versus SPMS patients without current disability increases (P < 0.0001). Moreover, Eomes level acted as a biomarker to predict SPMS patients at risk of disease worsening with over 80% accuracy (ROC-AUC = 0.8276). Overall, our results indicate that granzyme B-expressing Eomes⁺ T helper cells are involved in the pathogenesis of SPMS, with significant implications for SPMS biomarkers and therapeutic targets.

Eomesodermin in CD4+T cells is essential for Ginkgolide K ameliorating disease progression in experimental autoimmune encephalomyelitis

Eomesodermin (Eomes), a transcription factor, could suppress the Th17 cell differentiation and proliferation through directly binding to the promoter zone of the Rorc and Il17a gene, meanwhile the expression of Eomes is suppressed when c-Jun directly binds to its promoter zone. Ginkgolide K (1,10-dihydroxy-3,14-didehydroginkgolide, GK) is a diterpene lactone isolated from the leaves of Ginkgo biloba. A previous study indicated that GK could decrease the level of phospho JNK (c-Jun N-terminal kinase). Here, we reported the therapeutic potential of Ginkgolide K (GK) treatment to ameliorate experimental autoimmune encephalomyelitis (EAE) disease progression. Methods: EAE was induced in both wildtype and CD4-Eomes conditional knockout mice. GK was injected intraperitoneally. Disease severity, inflammation, and tissue damage were assessed by clinical evaluation, flow cytometry of mononuclear cells (MNCs), and histopathological evaluation. Dual-luciferase reporter assays were performed to measure Eomes transcription activity in vitro. The potency of GK (IC50) was determined using JNK1 Kinase Enzyme System. Results: We revealed that GK could ameliorate EAE disease progression by the inhibition of the Th17 cells. Further mechanism studies demonstrated that the level of phospho JNK was decreased and the level of Eomes in CD4+T cells was dramatically increased. This therapeutic effect of GK was almost completely interrupted in CD4-Eomes conditional knockout mice. Conclusions: These results provided the therapeutic potential of GK treatment in EAE, and further suggested that Eomes expression in CD4+T cells might be essential in this process.

Identifying the culprits in neurological autoimmune diseases

The target organ of neurological autoimmune diseases (NADs) is the central or peripheral nervous system. Multiple sclerosis (MS) is the most common NAD, whereas Guillain-Barré syndrome (GBS), myasthenia gravis (MG), and neuromyelitis optica (NMO) are less common NADs, but the incidence of these diseases has increased exponentially in the last few years. The identification of a specific culprit in NADs is challenging since a myriad of triggering factors interplay with each other to cause an autoimmune response. Among the factors that have been associated with NADs are genetic susceptibility, epigenetic mechanisms, and environmental factors such as infection, microbiota, vitamins, etc. This review focuses on the most studied culprits as well as the mechanisms used by these to trigger NADs.

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Neurological autoimmune diseases are caused by a complex interaction between genes, environmental factors, and epigenetic deregulation.

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Infectious agents can cause an autoimmune reaction to myelin epitopes through molecular mimicry and/or bystander activation.

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Gut microbiota dysbiosis contributes to neurological autoimmune diseases.

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Smoking increases the risk of NADs through inflammatory signaling pathways, oxidative stress, and Th17 differentiation.

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Deficiency in vitamin D favors NAD development through direct damage to the central and peripheral nervous system.