Altered microRNA Expression and Immunosuppressive Cytokine Production by Regulatory T Cells of Ulcerative Colitis Patients.

Regulatory T (Treg) cells are essential for maintenance of peripheral tolerance and prevention of autoimmune diseases in part by producing immunosuppressive cytokines. Recently, microRNAs (miRNAs) have also been involved in autoimmune disorders, not least for their crucial role in the regulation of Treg biology and function. We simultaneously investigated the concentration of IL-35, IL-10, TGF-β, and sCD25 in supernatant of cell culture and the expression patterns of several miRNAs in CD4(+)CD25(+) CD127(-/low) FoxP3(+) Tregs of ulcerative colitis (UC) patients. Significantly lower levels of IL-10 and IL-35 were observed in Treg cultures of UC patients. miR-21, miR-146a, and miR-155 levels were downregulated and miR-31 level was upregulated in Tregs of patients. Our results suggest that microRNAs may serve as a novel regulator in function and homoeostasis of UC Treg cells, providing a key role for them in pathophysiology of UC.