105 A peptide encoded by pri-miRNA-31 represses autoimmunity by promoting Treg differentiation

Recent evidence has revealed that small polypeptides (containing fewer than 100 amino acids) can be translated from noncoding RNAs (ncRNAs), which are usually defined as RNA molecules do not encode proteins. However, studies on functional products primary transcripts of microRNA (pri-miRNA) quite limited. Here, we describe a peptide termed miPEP31 is encoded by primiRNA-31. highly expressed in Foxp3+ regulatory T cells (Tregs) and significantly promotes the differentiation Tregs without affecting their inhibitory ability. Our results show cell-penetrating both vitro vivo. downregulates miR-31 expression, enhances peripheral Treg induction, dramatically suppresses experimental autoimmune encephalomyelitis. Mechanistically, acts transcriptional repressor inhibiting expression miRNA-31, negative regulator Tregs. reveal an indispensable role maintaining immune homeostasis promoting also present potential therapeutic for modulating miRNA treating diseases.