[Immunology for understanding the pathogenesis of multiple sclerosis]

Altered gene expression of miR-155 in peripheral blood mononuclear cells of Multiple sclerosis patients: Correlation with TH17 frequency, inflammatory cytokine profile and autoimmunity

In the chronic, organ-specific autoimmune disorder known as multiple sclerosis (MS), the myelin sheath is attacked by immune cells, leading to damage to the central nervous system (CNS). It has been discovered that miRNAs are important in the etiology of MS, since deregulation of miRNAs can lead to defects in immune tolerance. In this study, we sought to investigate the involvement of miR-155 in MS disorder through examination of its altered expression in peripheral blood mononuclear cells (PBMCs) of patients with MS in compare with healthy controls. Furthermore, we investigated the frequency of T helper 17 cells (Th17) in MS patients and analyzed not only the expression of inflammatory cytokines including IL-6, IL-17 and IL-21 in patients' PBMCs, but also their secreted levels in serum of patients suffering from MS. Subsequently, we assessed the correlation between miR-155 expression with Th17 frequency and levels of released cytokines in serum. Upregulated expression of miR-155 was detected in PBMCs of MS patients and the positive correlation between its expression with increased frequency of Th17 cells and their related inflammatory cytokine profile augmented secretion in serum were identified. In conclusion, our study revealed the significant association between Th17 frequency, increased level of cytokines related to Th17 differentiation and function with miR-155 augmented expression in PBMCs. So, our findings suggested that miR-155 and especially its expression in immune cells including effector T cells can be the target of future therapeutic strategies for the management and prevention of MS progression, however, further research is requisite before this approach can be utilized in clinical practice.

The circular RNA circINPP4B acts as a sponge of miR-30a to regulate Th17 cell differentiation during progression of experimental autoimmune encephalomyelitis

Circular RNAs (circRNAs) regulate gene expression and participate in various biological and pathological processes. However, little is known about the effects of specific circRNAs on T helper cell 17 (Th17) differentiation and related autoimmune diseases, such as multiple sclerosis (MS). Here, using transcriptome microarray analysis at different stages of experimental autoimmune encephalomyelitis (EAE), we identified the EAE progression-related circINPP4B, which showed upregulated expression in Th17 cells from mice with EAE and during Th17 differentiation in vitro. Silencing of circINPP4B inhibited Th17 differentiation and alleviated EAE, characterized by less demyelination and Th17 infiltration in the spinal cord. Mechanistically, circINPP4B served as a sponge that directly targeted miR-30a to regulate Th17 differentiation. Furthermore, circINPP4B levels were associated with the developing phases of clinical relapsing-remitting MS patients. Our results indicate that circINPP4B plays an important role in promoting Th17 differentiation and progression of EAE by targeting miR-30a, which provides a potential diagnostic and therapeutic target for Th17-mediated MS.