Résumé
Aim To investigate the effects of PTEN-induced putative kinase1(PINK1)mediated mitophagy on senescence and function of rat bone marrow endothelial progenitor cells(EPCs)by using small interfering RNA(siRNA)technology to knock down the PINK1 gene in rat bone marrow EPCs.Methods EPCs from bone marrow in rats were isolated, cultured and identified.After counting, EPCs were randomlydivided into control group, negative control group(NC siRNA), and Pink1 transfection group(PINK1 siRNA).The expression of PINK1 mRNA and protein in cells in various groups were detected by qRT-PCR and Western blot.At the same time, different time points were chosen to simulate the aging process based on the best knock down time.The senescence of cells was detected by SA-β-galactosidase staining and p16 protein expression.The function of cell proliferation, migration and tubule formation was detected by CCK-8, Transwell chamber and in vitro angiogenesis kit.ROS level was detected by flow cytometry.The expressions of PINK1, Parkin, LC3, and p62 were detected by Western blot.Mitochondria and autophagosomes were observed by transmission electron microscope.Results 48 h after PINK1 siRNA transfected, PINK1 was effectively knocked down.Compared with control group, the positive rate of blue staining and the expression of p16 protein in PINK1 siRNA group increased significantly 48 h and 96 h after transfection.The function of cell proliferation, migration and tubule formation decreased significantly.The level of ROS increased significantly, while the expression of PINK1, Parkin and LC3 protein decreased significantly, and p62 protein expression increased significantly.Under the transmission electron microscope, the mitochondria swelled and denatured, and the number of autophagosomes decreased in the PINK1 siRNA group.Conclusions The down-regulation of PINK1 gene can aggravate the senescence of EPCs, and PINK1 mediated mitophagy may participate in the regulation of senescence and function of EPCs.