Autophagy is involved in pulmonary artery endothelial cell apoptosis induced by cigarette smoke extract / 中国病理生理杂志

ABSTRACT

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.