Polygonati Rhizoma Attenuate the Replicative Senescence of Endothelial Progenitor Cells of Rats Via PINK1 Mediated Mitophagy

OBJECTIVE  To observe dynamically the effect of Polygonati Rhizoma(PR) on the mitochondrial function and mitophagy in the replicative senescence process of endothelial progenitor cells(EPCs) derived from rat bone marrow, investigating the attenuate effect of PR on the senescence of EPCs is related with PTEN-induced putative kinase1(PINK1) mediated mitophagy.

METHODS  EPCs derived from rat bone marrow were cultured and characterized. The 4th, 6th, and 8th passages of EPCs were divided into 7 groups: control group(treated with 10% blank serum), PR low, middle and high dose group(treated with 10% PR low, medium, and high dose drug-containing serum, respectively), PR low, middle and high dose groups with 3-methyl adenine(3-MA). Following a 48h intervention, the positive rate of cell senescence was assessed using β-galactosidase. Cellular function of proliferation, migration and tubule formation were evaluated using CCK-8, transwell chamber, and in vivo angiogenesis kit, respectively. Additionally, the levels of reactive oxygen species(ROS), mitochondrial membrane potential(MMP), and ATP content were measured using flow cytometry, JC-1 and chemiluminescence method. The expression of mitophagy related proteins PINK1, Parkin, microtubule-associated protein light chain 3(LC3) and P62 were detected by Western blotting.

RESULTS  EPCs were subcultured to the 4th, 6th and 8th passage, the positive rate of cell senescence increased gradually, accompanied by a significant decrease in proliferation, migration and tubule formation of EPCs. The level of ROS increased but the MMP and ATP content both decreased. The expression of PINK1, Parkin, and LC3 were down-regulated while P62 protein was up-regulated. However, PR treatment could reduce the positive rate of cell senescence, improve the cell proliferation, migration and tubular function, decrease the ROS level and increase the MMP and ATP content. The expression of PINK1, Parkin and LC3 were up-regulated while P62 protein was down-regulated after RP treatment. 3-MA significantly inhibited the above effects of RP on EPCs.

CONCLUSION PR could attenuate the replicative senescence of EPCs in rats by improving the mitochondrial function through PINK-mediated mitophagy.