microRNA-324-3p Promotes Osteoblasts Differentiation via Suppressing SMAD7

: Fracture healing is a complex dynamic process that involves the balance between osteoblasts and osteoclasts. Sev-eral microRNAs (miRNAs) have been shown to participate in fracture healing. In this study, we investigated the role of miR-324-3p in osteoblast differentiation. MC3T3-E1 cell differentiation was induced by icariin, and miR-324-3p expression levels during cell differentiation were measured using qRT-PCR. Cell proliferation and differentiation were assessed to eval uate the function of miR-324-3p. Luciferase activity was used for target gene verification. During MC3T3-E1 differentia tion, miR-324-3p levels gradually increased over time. Further experiments showed that miR-324-3p overexpression significantly promoted cell viability, whereas miR-324-3p downregulation showed the opposite effect. For cells with miR-324-3p mimic, the levels of bone sialoprotein, Runx2, osteocalcin, and alkaline phosphatase activity were significantly elevated. SMAD7 is the target gene of miR-324-3p, and its level is gradually downregulated during MC3T3-E1 cell differentiation. MiR-324-3p may promote MC3T3-E1 cell differentiation by targeting SMAD7.