机械牵张调控LRP6磷酸化介导心脏侧群干细胞增殖

Mechanical stretch promotes the proliferation of cardiac side population cells induced by the phosphorylation of LRP6

目的研究机械牵张对心脏侧群干细胞(cardiac side population cell,CSP)增殖的作用及机制。方法通过流式细胞仪分选并培养大鼠乳鼠CSP,牵张后观察细胞的增殖。并通过胸主动脉缩窄(transverse aorta constriction,TAC)建立压力负荷小鼠模型,流式细胞仪分选后观察CSP的比例。进一步通过荧光染色以及Western blot检测CSP的LRP6磷酸化水平。结果成功分离及培养CSP,机械牵张可促进CSP增殖。体内实验表明,压力负荷可明显促进CSP比例的升高。免疫荧光及Western blot实验表明,机械牵张可明显促进CSP的LPR6磷酸化。CSP过表达LRP6可明显增强机械牵张介导的促增殖效应。结论机械牵张可促进LRP6磷酸化,从而促进CSP增殖,有利于机体对病理性刺激产生适应性反应以维持心功能。

Objective To investigate the effect of mechanical stretch on the proliferation of cardiac side population cell （CSP） and to explore its potential mechanisms. Methods CSPs from neonatal rat were isolated by FACS analysis. The proliferation of cultured CSPs was examined with mechanical stretch. Transverse aorta constriction （TAC） was applied to mice to induce pressure overload. The ratio of CSPs was analyzed by FACS. The phosphorylation of LRP6 was determined by immunofluorescence staining and Western blot analysis. Results CSPs were isolated and cultured successfully. Mechanical stretch promotes the proliferation of CSPs. The ratio of CSPs in TAC mice was increased significantly compared to it in sham mice. Further analysis showed that mechanical stretch enhanced the phosphorylation of LRP6 by immunofluorescence staining and Western blot analysis. Overexpression of LRP6 greatly exaggerated the proliferation of CSPs induced by mechanical stretch. Conclusions Mechanical stretch promotes the proliferation of CSPs by the activation of LRP6. The finding provide an understanding on the mechanisms responsible for the proliferation of CSPs under pressure overload.