miR-483-3p promotes the osteogenesis of human osteoblasts by targeting Dikkopf 2 (DKK2) and the Wnt signaling pathway

Osteoporosis is a systemic metabolic bone disease during which bone mass decreases and bone quality is reduced. Maintaining the bone formation capacity of osteoblasts is crucial for the treatment of osteoporosis. In the present study, bioinformatics analysis was performed on online microarray expression profiles to identify miRNA(s) related to osteoblast proliferation and bone marrow-derived mesenchymal stem cell (BMSC) osteogenic differentiation. The specific effects of candidate miRNAs on cell proliferation, osteogenic differentiation and Wnt signaling-related factors were examined. As regards the downstream mechanisms, online tools were employed to predict the downstream targets of candidate miRNAs and the predicted miRNA-mRNA binding was verified. Finally, the dynamic effects of miRNAs and mRNAs were examined. The results revealed that miR-483-3p expression was decreased in bone tissue samples from patients with osteoporosis. In miR-483-3p-overexpressing human osteoblasts, cell viability, DNA synthesis capacity and osteogenesis were promoted, and the protein levels of Wnt1, β-catenin and cyclin D1 were increased. However, the protein receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) ratio and cell apoptotic rate were decreased. The Wnt signaling, antagonist Dikkopf 2 (DKK2), was targeted and negatively regulated by miR-483-3p. DKK2 knockdown exerted similar effects as miR-483-3p overexpression, while DKK2 overexpression inhibited cell viability, DNA synthesis capacity and osteogenesis. DKK2 overexpression also decreased the Wnt1, β-catenin, and cyclin D1 protein levels, whereas it promoted the the RANKL/OPG ratio and the apoptosis of human osteoblasts. DKK2 overexpression reversed the functions of miR-483-3p overexpression. On the whole, the findings of the present study demonstrate that the miR-483-3p/DKK2 axis modulates the bone formation process by affecting osteoblast proliferation, pre-osteoblast differentiation into mature osteoblasts and new bone matrix formation.