MicroRNA-146a as a potential regulator involved in the pathogenesis of atopic dermatitis

Previous studies have demonstrated that microRNA (miR)-146a is involved in the inflammatory response of atopic dermatitis (AD). The aim of the present study was to investigate the expression of miR-146a in the serum of patients with AD and in skin lesions of AD animal models. In addition, we aimed to predict and verify the target genes of miR-146a. miR-146a expression was measured in AD patient serum via reverse transcription-quantitative PCR. T-helper (Th)1 [CD4(+); interferon (IFN)-γ(+)] and Th2 [CD4(+); interleukin (IL)-4(+)] expression in peripheral blood mononuclear cells was evaluated using flow cytometry. Following the establishment of a 2,4-dinitrofluorobenzene-induced C57BL/6 mouse AD model, Th1 (CD4(+)IFN-γ(+)) and Th2 (CD4(+)IL-4(+)) expression was analyzed in murine spleen cells via flow cytometry. Plasmids were transfected into 293T cells and at 48 h post-transfection, cells were analyzed using a luciferase assay system. The results revealed that the AD group had a significantly lower Th1/Th2 ratio and a significantly higher miR-146a expression compared with the control group (P<0.05). Furthermore, a decreased Th1/Th2 ratio and a significantly increased miR-146a expression were observed in the model group compared with the control group (P<0.01). We also conducted a dual-luciferase assay to determine whether small ubiquitin-related modifier 1 (SUMO1) if the target gene of miR-146a. We observed a ~30% decrease in the relative luciferase activity in cells containing the 3′-untranslated region of SUMO1 + miR-146a). The results of the luciferase assay indicated that may be a direct mRNA target of miR-146a; however, the quantification of band density of SUMO1 expression following western blotting did not significantly differ. The development of animal models in AD research is of vital importance. The results revealed that miR-146a may be a potential regulator involved in the pathogenesis of AD. Furthermore, the current study determined that miR-146a could be a valuable marker of AD and thus, may be applied in the development of therapeutic strategies for treating AD.