miR-203a-3p promotes loureirin A-induced hair follicle stem cells differentiation by targeting Smad1.

MicroRNAs (miRNAs) participate in the repair of skin trauma. Our previous study indicated that loureirin A promoted hair follicle stem cells (HFSCs) to repair skin epidermis. However, the mechanism of miRNA-mediated regulation of loureirin A-induced HFSC differentiation remained to be explored. In the present study, HFSCs from rat vibrissa were identified by immunofluorescence in vitro. Microarray and quantitative real time polymerase chain reaction (qRT-PCR) analyses demonstrated that miR-203a-3p was upregulated in differentiated HFSCs induced by loureirin A. The expression of cytoskeletal keratin (CK) 5 and involucrin was promoted by miR-203a-3p mimics while repressed by a miR-203a-3p inhibitor. Smad1 was identified as a key target of miR-203a-3p using target prediction tools. Luciferase reporter gene test confirmed a special target association between miR-203a-3p and Smad1. Short interfering Smad1 was transfected into HFSCs, and the expression levels of CK5 and involucrin were upregulated. Thus, it can be inferred that miR-203a-3p negatively regulated the expression of Smad1 and promoted the differentiation of loureirin A-induced HFSCs. Bone morphogenetic protein (BMP) signal inhibition and Wnt activation co-regulate skin injury repair. BMP/Smad1 signaling is involved in maintaining the characteristics of HFSCs and inhibiting their differentiation. Our results showed that miR-203a-3p reduces Smad1 to release BMP inhibition. Taken together, miR-203a-3p/Smad1 is a potential therapeutic molecular target in skin wound healing, and may play an active role in wound repair and regenerative medicine.