miR-30b regulates chondrogenic differentiation of mouse embryo‑derived stem cells by targeting SOX9

: The present study aimed to investigate the mechanisms underlying microRNA (miRNA)-mediated regulation of chondrogenic differentiation. Mouse embryo-derived stem cells C3H10T1/2 were cultured and chondrogenic differentiation was induced using transforming growth factor-β3 (TGF-β3). In addition, miRNA expression profiles were detected via miRNA array analysis, and quantitative polymerase chain reaction was performed to verify the differentially expressed miRNAs. Furthermore, bioinformatics software was used to predict the putative targets and the prediction was validated by dual-luciferase reporter assays and western blot analysis. In addition, cell proliferation and glycosaminoglycans were measured by a direct cell count method and alcian blue staining, respectively. Compared with the control group, 86 miRNAs were identified as differentially expressed in TGF-β3-induced cells and the expression levels of 28 miRNAs were increased while the remaining 58 miRNAs exhibited a decline in expression. Amongst the differentially expressed miRNAs, miR-30b expression was observed to have significantly decreased during chondrogenic differentiation. SOX9 is a target gene of miR-30b, and miR-30b inhibits SOX9 expression during chondrogenic differentiation. Furthermore, the alcian blue staining results demonstrated that miR-30b inhibited early chondrogenic differentiation. However, the data of the present study indicated that miR-30b had no influence on C3H10T1/2 cell line proliferation. In conclusion, miR-30b is a key negative regulator of TGF-β3-induced C3H10T1/2 cell chondrogenic differentiation, which functions by directly targeting SOX9.