MicroRNA-194 reduces inflammatory response and human dermal microvascular endothelial cells permeability through suppression of TGF-β/SMAD pathway by inhibiting THBS1 in chronic idiopathic urticaria.

Chronic idiopathic urticaria (CIU) is a polyetiological dermatologic disease. Reports have stated that some microRNAs (miRNAs) have their roles to play in inflammatory response. In this present study, we aim to investigate whether miR-194 has an effect on attenuating inflammatory response and human dermal microvascular endothelial cells (HDMECs) permeability of CIU mast cells through TGF-β/SMAD pathway by binding to thrombospondin 1 (THBS1). The Gene Expression Omnibus database was used to obtain the CIU-related microarray data, and then the analysis of differentially expressed genes was conducted and the miRNA regulated by THBS1 was predicted. After transfection of different mimic, inhibitor, or small interfering RNA, the effect of miR-194 on inflammatory reaction, mast cell degranulation, histamine release rate, HDMECs permeability, and the expression of THBS1, interferon γ (IFN-γ), TGF-β, Smad3, and interleukin 4 (IL-4) were detected. THBS1 was verified to be the miR-194 target. After transfected with overexpressed miR-194 and si-THBS1, the degranulation rate, histamine release rate, and HDMECs permeability were significantly reduced, while the expression of IFN-γ was higher, and the expression of THBS1, TGF-β, Smad3, IL-4 was significantly lower, accompanied with alleviated inflammatory reaction. Our study provides evidence that miR-194 negatively modulates THBS1 and inhibits the activation of TGF-β/SMAD pathway, thereby alleviating the inflammatory response and HDMECs permeability of mast cells in CIU.