Silencing miR-199a-3p, Which Targets Integrin Β8 Prevents Steroid-induced Avascular Necrosis of the Femoral Head by Regulating Osteogenesis and Adipogenesis

Abstract BackgroundThe main pathogenesis of steroid-induced avascular necrosis of the femoral head (SANFH) is closely connected with osteogenesis and adipogenesis. MicroRNAs have been proved to play prominent roles in the initiation and progression of SANFH. The present study investigated the effects of silencing miR-199a-3p on the prevention and early treatment of SANFH. MethodsRT-PCR was used to detect the expression of miR-199a-3p. Western blotting was used to detect protein expression. Alkaline phosphatase (ALP) activity, alizarin red S staining, and oil red O staining were used to study the effect of miR-199a-3p on the osteogenic and adipogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and MC3T3-E1 cells. A dual-luciferase reporter assay was used to confirm the target relation of miR-199a-3p and integrin β8 (ITGB8). Animal study was used to explore the effect of silencing miR-199a-3p in vivo.ResultsMiR-199a-3p expression was upregulated in necrotic bone tissues and rBMSCs and MC3T3-E1 cells treated with 20 UM dexamethasone. Western blotting and a dual luciferase assay were employed to verify that miR-199a-3p directly targets ITGB8. Silencing of miR-199a-3p also promoted osteogenesis and inhibited adipogenesis of rBMSCs and MC3T3-E1 cells in the presence or absence of glucocorticoids. In addition, the silence of miR-199A-3p prevent SANFH by promoting osteogenesis in rats.ConclusionThe upregulation of miR-199a-3p induced by GCs could reciprocally regulate the adipo-osteogenic differentiation of rBMSCs and MC3T3-E1 cells by targeting ITGB8. The miR-199a-3p-ITGB8-FAK-Erk1/2-RUNX2 axis is a potential signaling mechanism, and inhibition of miR-199a-3p expression could promote osteogenesis and inhibit adipogenesis to alleviate the occurrence of SANFH.