自噬参与香烟烟雾提取物诱导的肺动脉内皮细胞凋亡

摘要

目的: 探讨自噬在香烟烟雾提取物(cigarette smoke extract, CSE)诱导人肺动脉内皮细胞(human pulmonary artery endothelial cells,HPAECs)凋亡中的作用.方法: 常规培养HPAECs,分为对照组、CSE组、3-甲基腺嘌呤(3-methyladenine,3-MA)组和3-MA+CSE组,应用Hoechst 33342 染色和 Annexin V/PI 流式细胞术检测细胞凋亡,单丹磺酰尸胺(monodansylcadaverine,MDC)染色观察细胞自噬泡形成,Western bolt 测定自噬相关蛋白 beclin-1、LC3 与cleaved caspase-3的水平.结果: MDC染色示CSE处理可以诱导细胞产生自噬泡,Western blot结果示自噬相关蛋白LC3及beclin-1表达升高,3-MA 预处理后抑制上述蛋白的表达.Hoechst 33342 染色和 Annexin V/PI 流式结果显示CSE组细胞凋亡率较对照组明显增加,在3-MA+CSE组,细胞凋亡率较CSE组进一步升高;同时,CSE组细胞cleaved caspase-3蛋白水平较对照组明显升高(P<0.05),3-MA+CSE组的caspase-3表达较CSE组进一步升高.结论: CSE能诱导HPAECs发生自噬和凋亡,抑制自噬能够进一步促进CSE对HPAECs的凋亡作用,这种作用可通过激活caspase-3实现.%AIM: To investigate the role of autophagy in the apoptosis of human pulmonary artery endothelial cells (HPAECs) induced by cigarette smoke extract (CSE).METHODS: HPAECs were cultured routinely.HPAECs were treated with CSE at different concentrations, and the cell viability was detected by MTT assay.HPAECs were divided into control group, CSE group, 3-methyladenine (3-MA) group and 3-MA+CSE group.The autophagy was observed under fluorescence microscope with monodansylcadaverine (MDC) staining.Annexin V/propidium iodide staining and Hoechst 33342 staining were employed to detect apoptosis.In addition, the protein levels of LC3, beclin-1 and cleaved caspase-3 were determined by Western blot.RESULTS: MDC staining showed the increased production of autophagic vacuoles was observed in CSE group.The results of Western blot showed that the expression levels of autophagy-related proteins LC3 and beclin-1 were increased, while 3-MA pretreatment inhibited the expression of these proteins and the production of autophagic vacuoles.Observation with Annexin V/propidium iodide staining and Hoechst 33342 staining showed that the apoptotic rate in CSE group was significantly higher than that in control group, and pretreatment with 3-MA induced further increase in the cell apoptosis.The protein level of cleaved caspase-3 in CSE group was significantly higher than that in control group (P<0.05), and 3-MA+CSE treatment induced the further increase in the protein level of cleaved caspase-3.CONCLUSION: CSE induces autophagy and apoptosis in the HPAECs.Inhibition of autophagy promotes the apoptosis induced by CSE in HPAECs, which can be achieved through activation of caspase-3.