低氧诱导因子修饰内皮祖细胞促血管新生的研究

Angiogenesis by hypoxia inducible factor-1α transfected endothelial progenitor cells

目的观察低氧诱导因子(hypoxia inducible factor-1α,HIF-1α)转染内皮祖细胞(endothelial progenitor cells,EPCs)后,EPCs在体外的扩增及迁移功能改变及对体内缺血下肢血管新生的影响。方法在人外周血EPCs中导入人HIF-1α基因。结果转染后的EPCs中HIF-1α、血管内皮生长因子(vascular endothelial growth factor,VEGF)mRNA及蛋白表达升高,并被特异性siRNA-HIF-1α中度抑制;功能学检测示HIF-1α过表达增加了EPC在体外的分化、扩增、迁移;内皮细胞(EC)标记物CD31、VEGFR2、eNOS及VEGF、NO分泌增加;移植HIF-1α-EPCs至缺血下肢后可见外源性EPCs存在于缺血部位;HIF-1α-EPCs较对照组进一步促进体内毛细血管数目增加。结论在体外,HIF-1α转染后的EPCs扩增及迁移功能改善;在体内,可促进缺血下肢的局部血管新生。

AIM To observe the ex vivo cell proliferation and migration and in vivo angiogenesis from hindlimb ischemia, hypoxia inducible factor-lα（HIF-1α） was introduced to endothelial progenitor cells （EPCs）. METHODS To address this issue, human endothelial progenitor cells were electroporated with human HIF-1α vector in vitro. RESULTS HIF-1α mRNA and protein expressions were increased after HIF-1α transfection. This was accompanied by VEGF mRNA induction and increased VEGF secretion. Hypoxia-stimulated VEGF mRNA induction was moderately abrogated by HIF-1α-specific siRNA. Functional studies showed that HIF-1α overexpression further promoted hypoxiainduced EPCs differentiation, proliferation and migration. The expressions of endothelial cell markers CD31, VEGFR2 （ FLK-1 ） and eNOS as well as VEGF and NO secretions were also increased. Furthermore, in an in vivo model of hindlimb ischemia, HIF-1α-transfected EPCs had clearly homed to ischemia. A higher revascularization potential was also evidenced by increased capillary density at the injury site. CONCLUSION In vitro, HIF-1α modified EPCs enhances EPCs proliferation and migration. In vivo, gene-modified EPCs facilitate the strategy of cell transplantation to augment naturally impaired neovascularization in an animal model of experimentally induced limb ischemia.