miR-135a-5p regulates RUNX2 expression in BMP2 treated C2C12 cells. C2C12 cells were treated with 2 nM BMP2 for 24 h following transfection with miR-135a-5p mimic, mimic control, control-plasmid, RUNX2-plasmid, miR-135a-5p mimic+control-plasmid or miR-135a-5p mimic+RUNX2-plasmid, respectively, for 2 h. The relative RUNX2 (A) protein and (B) mRNA expression levels were detected by western blot and RT-qPCR analysis, respectively, in C2C12 cells following transfection with control-plasmid and RUNX2-plasmid. The relative RUNX2 (C) protein and (D) mRNA expression level was detected by western blot and RT-qPCR analysis, respectively, in C2C12 cells following transfection with mimic control, miR-135a-5p mimic, miR-135a-5p mimic+control-plasmid or miR-135a-5p mimic+RUNX2-plasmid. Data are presented as the mean ± standard deviation from three independent experiments. **P<0.01 vs. Control; ##P<0.01 vs. Mimic group. miR, microRNA; RUNX2, runt related transcription factor 2; BMP2, bone morphogenetic protein 2; RT-qPCR, reverse transcription-quantitative polymerase chain reaction.