震荡流体剪切力通过ERK5信号通路促进成骨细胞增殖

目的探讨震荡流体剪切力(oscillatory shear stress,OSS)通过ERK5信号通路在诱导成骨细胞增殖中发挥的作用。方法对成骨MC3T3-E1细胞进行不同的处理,分为正常组、OSS组、XMD8-92组和OSS+XMD8-92组。采用MTT实验分别测定4组细胞的增殖活性并绘制生长曲线;蛋白免疫印迹法分别检测P-ERK5、ERK5和Cyclin D1等蛋白水平变化。结果 OSS可显著增加成骨MC3T3-E1细胞增殖活性,但此效应可被ERK5高选择性抑制剂XMD8-92阻断。OSS可显著上调Cyclin D1的表达,而XMD8-92可显著下调OSS诱导的Cyclin D1的表达。结论 OSS通过激活ERK5信号通路促进成骨细胞增殖,Cyclin D1是ERK5信号通路下游的重要靶点基因。

Oscillatory shear stress promotes MC3T3-E1 cells proliferation via ERK5 signaling pathway

Objective The effect of ERK5 pathway on oscillatory shear stress (OSS) increased MC3T3-E1 cells proliferation was explored. Methods MC3T3-E1 cells were treated with OSS, XMD8-92 alone, or in combination. The proliferation absorbance of osteoblasts was detected using MTT assay, the protein levels of Extracellular signal-regulated kinase 5 (ERK5), P-ERK5, and Cyclin D1 were evaluated with western blot analysis. Results OSS (0.6±12 dyn/cm2) for 1h significantly enhanced osteoblasts proliferation, but the cellular proliferation was blocked by XMD8-92 (a highly selective inhibitor of ERK5 activity), suggesting that ERK5 is involved in OSS-induced osteoblasts proliferation. The protein levels of Cyclin D1 under OSS were elevated, but XMD8-92 markedly suppressed Cyclin D1 expression with exposure to OSS. Conclusions OSS promotes osteoblasts proliferation via ERK5 pathway, and Cyclin D1 is the crucial downstream target of ERK5 pathway.