Downregulated microRNA-23b promotes BMP9-mediated osteogenesis in C2C12 myoblast cells by targeting Runx2

MicroRNAs are identified as negative regulators in gene expression through silencing gene expression at the post-transcriptional and translational levels. Bone morphogenetic protein 9 (BMP9) is the most effective in inducing osteogenesis in the BMP family, the members of which were originally identified as osteoinductive cytokines. In the current study, the role of miR-23b in the progression of BMP9-induced C2C12 myoblasts was investigated. The results indicated that miR-23b was significantly downregulated in C2C12 myoblasts induced by BMP9. Overexpression of miR-23b significantly inhibited osteogenesis in the C2C12 myoblasts. In addition, it was observed that Runx2 was negatively regulated by miR-23b at the post-transcriptional level, via a specific target site within the 3′UTR of Runx2. Knockdown of Runx2 promoted miR-23b-induced inhibition of osteogenesis in C2C12 myoblasts. The expression of Runx2 was observed to be frequently upregulated in osteoblast cell lines and inversely correlated with miR-23b expression. Thus, the results of the present study suggest that miR-23b inhibits BMP9-induced C2C12 myoblast osteogenesis via targeting of the Runx2 gene, acting as a suppressor. The current study contributes to the understanding of the functions of BMP9 in ossification.