miR-195对人骨髓间充质干细胞成骨分化的影响

miR-195 effect on osteogenic differentiation of human bone marrow mesenchymal stem cells

BACKGROUND:Previous studies have found that the expression level of miR-195 in differentiated human bone marrow mesenchymal stem cells (hBMMSCs) is significantly higher than that in undifferentiated hBMMSCs. However, miR-195 effect during this differentiation process and possible mechanism remain unclear. OBJECTIVE:To explore the effect of miR-195 on osteogenic differentiation of hBMMSCs and possible mechanism. METHODS:hBMMSCs were isolated and cultured in vitro. Alkaline phosphatase activity, Runx2, osteopontin and SMAD7 protein expression and miR-195 expression level during osteogenic differentiation of hBMMSCs were determined by alkaline phosphatase kit, western blot and real-time PCR, respectively. miR-195-downexpressed hBMMSCs were constructed by lipofection transfection, and were used to investigate the effect of miR-195 was on osteogenic differentiation of hBMMSCs. Dual luciferase reporter assay was used to identify whether the 3’UTR of SMAD7 mRNA was a binding target of miR-195. In addition, we transfected hBMMSCs with SMAD7 cDNA (pcDNA-SMAD7), and investigated the effect of SMAD7 on osteogenic differentiation of hBMMSCs. RESULTS AND CONCLUSION:The isolated and cultured hBMMSCs had good osteogenic differentiation ability in vitro. Expression level of miR-195 was increased with the increasing of induction time, and the expression level of SMAD7 was reversed. miR-195 promoted osteogenic differentiation of hBMMSCs. Luciferase assay confirmed that miR-195 targeted SMAD7 directly, and overexpression of SMAD7 inhibited the osteogenic differentiation of hBMMSCs. Taken together, miR-195 promotes osteogenic differentiation of hBMMSCs by targeting SMAD7.