The role of microRNA-146a in the regulation of CD4+ T lymphocytes and the pathogenesis of psoriasis vulgaris

Objective To investigate the effects of miRNA-146a on the differentiations and functions of CD4+ T lymphocytes in patients with psoriasis vulgaris. Methods Thirty patients with psoriasis vulgaris and twenty heathy subjects were enrolled in this study. Quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression of miRNA-146a in CD4+ T lymphocytes isolated from the peripheral blood samples. The levels of IFN-γ and IL-4 in serum samples were determined by using enzyme-linked immunosorbent assay (ELISA). Mononuclear cells were isolated from human peripheral blood samples by using Ficoll-Hypaque density-gradients centrifugation, from which the CD4+ T lymphocytes were separated by magnetic-activated cell sorting. The CD4+ T cells (2×106/ml) were seeded in culture plates with 6 wells. The CD4+ T lymphocytes were divided into 3 groups including the control group, miRNA-146a group and miRNA-146a inhibitor group. The numbers of Th1 and Th2 cells were measured by flow cytometry analysis (FACS). The expression of IFN-γRα, T-bet and GATA-3 at mRNA and protein levels were measured by using RT-PCR and Western blot assay, respectively. The levels of IFN-γ and IL-4 in culture supernatants of CD4+ T lymphocytes were detected by using ELISA. Results In comparison with the normal control group, there were significant increases in the expression of miRNA-146a in CD4+ T lymphocytes and the level of IFN-γ in serum samples from patients with psoriasis vulgaris [(2.43±0.94) vs (1.05±0.23), (27.69±7.64) ng/L vs (9.75±2.81) ng/L, all P 0.05). The miRNA-146a inhibitor could effectively attenuate the effects of miRNA-146a on Th1 cells. Conclusion The miRNA-146a could promote the differentiation and enhance the function of Th1 cells. It might play an important role in the pathogenesis of psoriasis vulgaris. Key words: Psoriasis vulgaris; microRNA; T lymphocyte; Cytokine