MicroRNA signature of regulatory T cells in health and autoimmunity

MicroRNAs (miRNAs) are small RNA molecules with regulatory functions on the expression of genes through binding directly to target messenger RNA (mRNA) transcripts, eventuating in gene expression suppression via translational hindrance and/or target mRNA cleavage. These molecules have been established to participate in numerous critical cellular settings, including differentiation, development, and function of immune cells. As an important suppressor cell of immune system, regulatory T cells (Tregs) are important in modulating the immune homeostasis as well as tolerance to self-antigens. Despite identification of numerous transcription factors, cytokines, and other mediators regulate the biology of Tregs, investigations have demonstrated that noncoding RNAs are involved in several mechanisms of the regulation of Treg cells. On the other side, dysregulation of expression of several miRNAs has been reported in Tregs, implicating to the impaired function of these regulatory cells, resulting in autoimmune and other immune-based disorders. In this review, we aim to go through the overall microRNA network and specific miRNAs that are involved in the development, differentiation, and function of Tregs. Moreover, an overview was provided with respect to the role of aberrant expression of miRNAs in Tregs of autoimmune diseases such as multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, diabetes, and psoriasis.