基质衍生因子1诱导高血压脑出血患者内皮祖细胞增殖迁移的机制

Mechanism of Stromal derived factor on the proliferation and migration of endothelial progenitor cells

目的 观察基质衍生因子-1（SDF-1）对高血压脑出血患者内皮祖细胞（EPCs）增殖迁移能力的影响并探讨其作用机制.方法 抽取急性期高血压脑出血患者空腹外周静脉血,分离并贴壁培养EPCs 6 d后,用含有不同浓度SDF-1培养基培养24h,测定细胞增殖、迁移能力,趋化因子受体4（CXCR4）和黏附分子整合素α5β1（α5β1）蛋白表达水平;采用小于扰RNA （siRNA）转染法观察CXCR4 siRNA对EPCs增殖、迁移能力的影响;加入抗α5β1抗体,进一步探讨α5β1在EPCs增殖迁移中的作用.结果 SDF-1剂量依赖性增加高血压脑出血患者EPCs增殖及迁移能力,在浓度为80 μg/L时达到高峰（A值：0.57 ±0.03 P ＜0.05）;进一步分析表明,SDF-1能够诱导CXCR4蛋白大量表达[（2.30±0.05）倍,P＜0.05],CXCR4 siRNA处理后,SDF-1诱导的EPCs增殖及迁移能力明显下降（A值：0.363±0.020）;此外,SDF-1显著性诱导α5β1的表达[（1.65±0.06）倍,P＜0.05],且CXCR4 siRNA预处理后SDF-1诱导的α5β1的表达明显下降[（0.71±0.04）倍];加入o5β1抗体后,SDF-1/CXCR4诱导的EPCs增殖及迁移能力明显下降[A值：0.311±0.037,迁移细胞数：（25.52±5.60）个].结论 SDF-1剂量依赖性地增强急性期高血压脑出血患者EPCs增殖及迁移能力,主要是通过CXCR4介导α5β1通路来实现的,提示SDF-1/CXCR4-α5β1可作为受损后血管修复的潜在靶点.

Objective To study the possible mechanism of stromal derived factor-1 （SDF-1） on proliferation and migration of endothelial progenitor cells （EPCs） in patients with hypertensive intracerebral hemorrhage,so as to explore the SDF-1/CXC chemokine receptor-4 （CXCR4） axis as a target participate in vascular repairment.Methods The endothelial progenitor cells were isolated from 15 ml peripheral venous blood in male patients with acute cerebral hemorrhage.Six days later,the culture EPCs were stimulated with various concentrations of SDF-1 for 24 h.Then,3-（4,5-Dimethyl-2-thiazolyl）-2,5-diphenyl-2H-tetrazolium bromide （MTT） assay was used to assess the proliferation of EPCs,and cell migration was analyzed by transwell chamber assay.Furthermore,the expression levels of CXCR4 and α5β1 protein were detected by Western blotting after pretreatment with the chemically synthesized CXCR4-siRNA or anti-α5 β1 antibody.Results SDF-1 dose-dependently increased the proliferation and migration of EPCs in patients with hypertensive cerebral hemorrhage （A：0.57 ± 0.03,P 〈 0.05） ; further mechanism analysis showed that SDF-1 induced the expression of CXCR4 protein with an about two fold increase （P 〈 0.05）,which was accounted for SDF-1-induced cell proliferation and migration as pretreatment with CXCR4 siRNA significantly abolished EPCs proliferation and migration induced by SDF-1 （A：0.363 ± 0.020）.Furthermore,SDF-1 enhanced the expression of α5β1 protein with an about two fold increase by CXCR4 pathway,because preconditioning with CXCR4 siRNA obviously attenuated SDF-1-induced upregulation of α5β1 expression.Further analysis confirmed that pretreatment with α5β1 antibody dramatically inhibited α5β1 expression,concomitant with a significant decrease in EPCs proliferation and migration induced by SDF-1/ CXCR4 （A：0.311 ±0.037,migration cells：25.52 ±5.60）.Conclusion SDF-1 dose-dependently increased EPCs proliferation and migration in patients with acute cerebral hemorrhage through CXCR4-mediated α5β1 pathway.Consequently,our findings will clarify a new explanation about how SDF-1 induced EPCs proliferation and migration,and provide a potential target for vascular repair after damage.