miRNAs and T cell-mediated Immune Response in Disease.

We reviewed the role of miRNAs in the regulation of T cell differentiation and function in cardiometabolic inflammatory diseases, such as obesity, type 2 diabetes, atherosclerosis, and autoimmune diseases, such as type 1 diabetes, rheumatoid arthritis, asthma, and cancer. Cardiometabolic diseases, type 1 diabetes, and rheumatoid arthritis are characterized by miRNA expression profiles that favor the differentiation of T helper 1 and 17 cells and cytotoxic cells and a decrease in T helper 2 cells, regulatory T cells, and myeloid-derived suppressor cells. Asthma is characterized by changes in miRNAs that favor the differentiation of T helper 2 cells. Finally, cancer is characterized by miRNA profiles that cause a decrease in T helper 1 and 17 cells and cytotoxic cells and an increase in T helper 2 cells, regulatory T cells, and myeloid-derived suppressor cells. In particular, differences in the expression of miR-155 and a cluster containing Let-7, miR-10a, miR-17-92, miR-34a, miR-142, and miR-150 may determine whether the balance flips towards cytotoxicity or immunosuppression. High levels of miR-21 and miR-29 and low levels of miR-150 are associated with T cell profiles that protect against inflammatory and autoimmune diseases associated with tissue damage but also induce tumor growth. All these miRNAs were found to be associated with disease progression and/or response to therapy in one or more of the diseases under study. Therefore, studies on the value of the identified miRNA clusters in predicting disease progression and selecting therapies that may yield gains in treatment costs are warranted.