Effects of autophagy on cell migration and apoptosis of endothelial progenitor cells in hypoxic environment / 解放军医学杂志

ABSTRACT

Objective To investigate the effects of autophagy on cell migration and apoptosis of endothelial progenitor cells (EPCs) in hypoxic environment.Methods Rats' bone marrow-derived EPCs were isolated by density-gradient centrifugation,identified with double-fluorescent staining method,and then divided into 4 groupsnormoxia (hypoxia 0h),hypoxia 1h,hypoxia 3h and hypoxia 6h groups for detecting the effects of hypoxia on EPCs migration and apoptosis.Transwell chambers and flow cytometry were used to detect cell migration and apoptosis respectively,and Western blotting was performed to detect the changes of autophagy-related proteins,including microtubule associated protein 1 light chain 3 (LC3-Ⅱ / Ⅰ) and ubiquitin of p62.To investigate the effects of hypoxic-induced autophagy on EPCs migration and apoptosis,cells were divided into 4 groupshypoxia 0h,hypoxia 3h,hypoxia 3h+ShAtg7 and ShAtg7 groups,and then to detect again the EPCs migration and apoptosis.Results Compared to hypoxia 0h group,the EPCs migration markedly reduced and apoptosis increased in hypoxic 3h and 6h groups with statistically significant difference (P＜0.05).Western blotting showed the expressions of LC3-Ⅱ / Ⅰ significantly increased and of p62 decreased in EPCs by hypoxic treatment for 3 and 6 hours (P＜0.05),implying the increases of autophagy level.After inhibiting autophagy by silencing Atg7,hypoxia 3h+ShAtg7 group further reduced EPCs migration (P＜0.05) and aggravated apoptosis (P＜0.05) compared with hypoxia 3h group.Conclusion Autophagy may play a cytoprotective role through promoting EPCs migration and decreasing EPCs apoptosis in hypoxic environment.