MiRNA-365a-3p promotes the progression of osteoporosis by inhibiting osteogenic differentiation via targeting RUNX2

OBJECTIVE: The aim of this study was to explore the exact role of miRNA-365a-3p in the progression of osteoporosis, as well as its function in regulating osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). PATIENTS AND METHODS: The serum level of miRNA-365a-3p in osteoporosis patients and normal controls was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). After transfection of miRNA-365a-3p mimics, miRNA-365a-3p inhibitor or si-RUNX2 in hBMSCs, the relative expression levels of miRNA-365a-3p, osteocalcin (OCN), osteopontin (OPN) and collagen I were determined by qRT-PCR. Western blot was conducted to examine the protein expression of RUNX2 influenced by miRNA-365a-3p. Subsequently, the regulatory effects of miRNA-365a-3p and RUNX2 on osteogenic differentiation and capability of mineralization were evaluated by alkaline phosphatase (ALP) determination and alizarin red staining, respectively. Furthermore, the binding relationship between miRNA-365a-3p and RUNX2 was predicted and verified by miRanda and Dual-Luciferase reporter gene assay, respectively. RESULTS: MiRNA-365a-3p was highly expressed in osteoporosis patients. The expression of miRNA-365a-3p in hBMSCs decreased gradually with the prolongation of osteogenic differentiation. The subsequent results showed that RUNX2 could bind to miRNA-365a-3p, which was negatively regulated by miRNA-365a-3p in hBMSCs. Down-regulation of miRNA-365a-3p significantly decreased the expression levels of OCN, OPN and collagen I. Furthermore, overexpression of miRNA-365a-3p markedly weakened the capability of mineralization of hBMSCs, whereas was further reversed by transfection of si-RUNX2. CONCLUSIONS: MiRNA-365a-3p negatively regulates osteogenic differentiation of hBMSCs by targeting RUNX2, thus promoting the progression of osteoporosis.