Role And Mechanisms Of Autophagy In AGE-BSA-Induced Injury Of Human Umbilical Vein Endothelial Cells

Objective: The aim of our study was to investigate the protective effects of Paeoniflorin(PF) against injury induced by AGE-modified bovine serum albumin(AGEBSA) in human umbilical vein endothelial cells(HUVECs), and to examine the underlying mechanisms of these effects.Methods: 1. AGE-BSA was used to induce injury in HUVECs. MTT assay was used to examine the cell viability after AGE-BSA treatment for 6h, and pretreated with 25μM PF. Western blot assay was applied to examine the expression of the LC3、P62、RAGE、Atg5. 2. For function-blocking experiments, we used small interfering RNA molecules(si RNA) for blocking the experiments of Atg5 and RAGE gene. This was used to assess the change of the cell viability and protein expression levels.Results: 1. The stimulation by 100 μg/m L AGE-BSA for 6h reduced the viability of HUVECs compared with the control group(P<0.001). However, pretreatment with PF restored cell viability in a dose-dependent manner. AGE-BSA increased the levels of microtubule-associated protein light chain 3-II(LC3-II) and the receptor for advanced glycation end products(RAGE) compared with the control group. Expression of p62 protein was also increased, but not at a statistically significant level. Pretreatment with 25μM PF further increased levels of LC3-II and RAGE(P<0.05), but reduced the expression of p62(P<0.05). 2. In cells transfected with Atg5 and RAGE si RNA, cell viability and expression of LC3-II decreased in both the AGE-BSA and PF + AGE-BSA treatments.Conclusion:PF can protect HUVECs from AGE-BSA-induced injury by upregulating autophagy and promoting the completion of autophagy flux.RAGE plays an important role in this autophagic protection effect.