Objective: Wnt/β-catenin signaling pathway promotes osteoblasts (OBs) differentiation through up-regulating osteoblast-specific gene runt-related transcription factor 2 (RUNX2) expression. It was showed that microRNA-214 (miR-214) was abnormally increased in bone tissue from osteoporosis patients, suggesting its role in osteogenesis. Bioinformatics analysis revealed the complementary binding site between miR-214 and 3'-UTR of β-catenin. This study investigated the effects of miR-214 in regulating β-catenin expression and bone marrow mesenchymal stem cells (BMSCs) differentiating into OB.
Materials and methods: BMSCs were induced to differentiate to OB in a specific medium. MiR-214, β-catenin, and RUNX2 expressions were detected. The regulatory relationship between miR-214 and β-catenin was confirmed by dual luciferase reporter gene assay. BMSCs were divided into five groups, including agomir-control, miR-214 agomir, pGPU6-normal control group (pGPU6-NC), pGPU6-β-catenin, and miR-214 agomir + pGPU6-β-catenin groups. β-catenin and RUNX2 levels were tested after 21 days' induction. OB differentiation degree was evaluated by alizarin red staining.
Results: MiR-214 was down-regulated, while β-catenin and RUNX2 were enhanced in the process of BMSCs differentiating into OBs. MiR-214 agomir and/or β-catenin shRNA pGPU6-β-catenin transfection significantly reduced β-catenin expression, declined RUNX2 level, and attenuated OB differentiation in BMSCs.
Conclusions: Wnt/β-catenin signaling pathway was enhanced, while the miR-214 level was decreased in the process of BMSCs differentiating into OBs. Up-regulation of miR-214 inhibited the OB differentiation of BMSCs through targeted suppressing β-catenin expression and attenuating Wnt/β-catenin signaling pathway activity.