Multiple sclerosis (OMIM 126200) is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability.1 Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals;2,3 and systematic attempts to identify linkage in multiplex families have confirmed that variation within the Major Histocompatibility Complex (MHC) exerts the greatest individual effect on risk.4 Modestly powered Genome-Wide Association Studies (GWAS)5-10 have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects play a key role in disease susceptibility.11 Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the Class I region. Immunologically relevant genes are significantly over-represented amongst those mapping close to the identified loci and particularly implicate T helper cell differentiation in the pathogenesis of multiple sclerosis.

The Multiple Sclerosis Severity Score (MSSS) is a powerful method for comparing disease progression using single assessment data. The Global MSSS can be used as a reference table for future disability comparisons. While useful for comparing groups of patients, disease fluctuation precludes its use as a predictor of future disability in an individual.

MicroRNAs (miRNAs) are an emerging group of short, noncoding RNAs that play an important role in regulating expression of classical genes. Thus far little is known about their role in autoimmune demyelination. In this study, we analyzed changes in the miRNA profile in CD4 + T cells that occurred during the recognition of the myelin autoantigen, MOG . We found that, both in vivo and in vitro, myelin antigen stimulation resulted in significant up-regulation of miR-301a, miR-21, and miR-155. Furthermore, these three miRNAs were overexpressed in T cells infiltrating the CNS in animals with experimental autoimmune encephalomyelitis. Use of specific miRNA antagonists, antagomirs, revealed that miR-301a contributed to the development of the T-helper type 17 subset via targeting the IL-6/23-STAT3 pathway. This contribution appeared to be mediated by the miR-301a effect on the expression of the PIAS3, a potent inhibitor of the STAT3 pathway. Manipulation of miR-301a levels or PIAS3 expression in myelin-specific CD4 + T cells led to significant changes in the severity of experimental autoimmune encephalomyelitis. Thus, we have identified a role of miR-301a in regulating the function of myelinreactive T-helper type 17 cells, supporting a role for miR-301a and PIAS3 as candidates for therapeutic targets for controlling of autoimmune demyelination.M ultiple sclerosis (MS) is an organ-specific autoimmune disease manifested by chronic inflammatory demyelination of the CNS. CD4 + T-cell-mediated autoimmunity, with a critical role of a putative myelin autoantigen, has long been accepted as one of the most important aspects of MS pathogenesis, especially for the early initiation of disease (1). This understanding has been particularly complemented by the research on the MS animal model, experimental autoimmune encephalomyelitis (EAE). T-helper type 1 (Th1) cells, characterized by the expression of the transcription factor T-bet and the production of IFN-γ, originally were considered the major effector T-helper cells that mediate the pathogenesis of autoimmune demyelination (2). More recently another subset of T-helper cells, Th17, characterized by expression of the transcription factors retinoic acid receptor-related orphan receptor alpha (ROR-α) and retinoic acid receptor-related orphan receptor gamma t (ROR-γt) and by the production of IL-17, has been considered pivotal for the propagation of autoimmune demyelination (3). Mice with impaired numbers or function of Th17 cells, particularly mice deficient in the cytokines IL-6 or IL-23, are largely resistant to EAE (4-6). However, precise mechanisms governing the development and function of Th17 cells resulting in autoimmune demyelination are still unclear. Thus, Th17-targeting therapeutic approaches for MS have not yet been established.MicroRNAs (miRNAs) have begun to emerge as an important component in the differentiation and function of cells involved in the immune response. miRNAs operate as noncoding RNA molecules ∼22 nt in length that are processed from larger transcripts o...

These data show that circulating exosomes have a distinct RNA profile in RRMS. Because putative targets for these miRNAs include the signal transducer and activator of transcription 3 and the cell cycle regulator aryl hydrocarbon receptor, the data suggest a disturbed cell-to-cell communication in this disease. Thus, exosomal miRNAs might represent a useful biomarker to distinguish multiple sclerosis relapse. Ann Neurol 2017;81:703-717.

Vα14 invariant (Vα14i) NKT cells are a subset of regulatory T cells that utilize a semi-invariant TCR to recognize glycolipids associated with monomorphic CD1d molecules. During development in the thymus, CD4+CD8+ Vα14i NKT precursors recognizing endogenous CD1d-associated glycolipids on other CD4+CD8+ thymocytes are selected to undergo a maturation program involving sequential expression of CD44 and NK-related markers such as NK1.1. The molecular requirements for Vα14i NKT cell maturation, particularly at early developmental stages, remain poorly understood. In this study, we show that CD4-Cre-mediated T cell-specific inactivation of c-Myc, a broadly expressed transcription factor with a wide range of biological activities, selectively impairs Vα14i NKT cell development without perturbing the development of conventional T cells. In the absence of c-Myc, Vα14i NKT cell precursors are blocked at an immature CD44lowNK1.1− stage in a cell autonomous fashion. Residual c-Myc-deficient immature Vα14i NKT cells appear to proliferate normally, cannot be rescued by transgenic expression of BCL-2, and exhibit characteristic features of immature Vα14i NKT cells such as high levels of preformed IL-4 mRNA and the transcription factor promyelocytic leukemia zinc finger. Collectively our data identify c-Myc as a critical transcription factor that selectively acts early in Vα14i NKT cell development to promote progression beyond the CD44lowNK1.1− precursor stage.