miR-485 regulates Th17 generation and pathogenesis in experimental autoimmune encephalomyelitis through targeting STAT3.

Experimental autoimmune encephalomyelitis (EAE) is an induced autoimmune disease widely used as an animal model for multiple sclerosis, which is mainly characterized by demyelination, axonal loss, as well as neurodegeneration of central nervous system (CNS). T-helper (Th) 17 cell that generate interleukin-17 (IL-17) plays a key role in its pathogenesis. Their activity and differentiation are tightly regulated by some cytokines and transcription factors. Certain microRNAs (miRNAs) are involved in the pathogenesis of various autoimmune disorders, including EAE. Our research detected a novel miRNA that can regulate EAE. According to the results, during EAE, the expression of miR-485 notably lowered, and STAT3 was significantly increased. It was discovered that miR-485 knockdown in vivo upregulated Th17-associated cytokines and aggravated EAE, while the overexpressed miR-485 down-regulated Th17-associated cytokines and mitigated EAE. The up-regulation of miRNA-485 in vitro inhibited Th17-associated cytokines expression within EAE CD4+ T cells. Furthermore, as revealed by target prediction and dual-luciferase reporter assays, miR-485 directly targets STAT3, a gene that encodes a protein responsible for Th17 generation. Overall, miR-485 exert vital functions in Th17 generation and EAE pathogenesis.