Fluid Shear Stress Regulates BMP2/BMP7in MC3T3-E1Osteoblastic Cells Via ERK5Signaling Pathway

Objective:Small interfering RNA (siRNA) was used to silence the ERK5gene expression. This research was to investigate the effect of ERK5signaling pathway on bone morphogenetic protein (BMP) BMP2/BMP7mRNA and protein expression induced by fluid shear stress (FSS) on the MC3T3-E1osteoblastic cells.Methods:MC3T3-E1osteoblastic cells were divided into four groups:blank group, FSS group, siERK5group, FSS+siERK5group. Real-time PCR was used to detect the ERK5mRNA expression in different concentrations of ERK5siRNA. Fluid shear stress of12dyne/cm2was loaded with MC3T3-E1osteoblastic cells. Real-time PCR and Western blotting were performed to evaluate the cellular proliferation and BMP2/BMP7mRNA and protein expression, respectively.Results:Different concentrations of ERK5siRNA,20,40,60,80nmol/L ERK5were used to silence ERK5mRNA in MC3T3-E1osteoblastic cells for24hours. The results showed that60nmol/L ERK5was the superior concentration for silencing ERK5mRNA. The expression of ERK5mRNA was significantly inhabited by76.8±2.2%(P<0.01). FSS significantly stimulated the expression of BMP2/BMP7mRNA and protein (P<0.05), but this action could be blocked by ERK5signaling pathway (P<0.05).Conclusion:ERK5signaling pathway significantly inhabited the expression of BMP2/BMP7mRNA and protein induced by fluid shear stress, and it plays essential roles in the proliferation and differentiation expression in the MC3T3-E1osteoblastic cells.