title: Bcl-2 silencing attenuates hypoxia-induced apoptosis resistance in pulmonary microvascular endothelial cells.
abstract: Pulmonary arterial hypertension (PAH) is a life-threatening disorder that ultimately causes heart failure. While the underlying causes of this condition are not well understood, previous studies suggest that the anti-apoptotic nature of pulmonary microvascular endothelial cells (PMVECs) in hypoxic environments contributes to PAH pathogenesis. In this study, we focus on the contribution of Bcl-2 and hypoxia response element (HRE) to apoptosis-resistant endothelial cells and investigate the mechanism. PMVECs obtained from either normal rats or apoptosis-resistant PMVECs obtained from PAH rats were transduced with recombinant lentiviral vectors carrying either Bcl-2-shRNA or HRE combined Bcl-2-shRNA, and then cultured these cells for 24 h under hypoxic (5% O2) or normoxic (21% O2) conditions. In normal PMVECs, Bcl-2-shRNA or HRE combined with Bcl-2-shRNA transduction successfully decreased Bcl-2 expression, while increasing apoptosis as well as caspase-3 and P53 expression in a normoxic environment. In a hypoxic environment, the effects of Bcl-2-shRNA treatment on cell apoptosis, and on Bcl-2, caspase-3, P53 expression were significantly suppressed. Conversely, HRE activation combined with Bcl-2-shRNA transduction markedly enhanced cell apoptosis and upregulated caspase-3 and P53 expression, while decreasing Bcl-2 expression. Furthermore, in apoptosis-resistant PMVECs, HRE-mediated Bcl-2 silencing effectively enhanced cell apoptosis and caspase-3 activity. The apoptosis rate was significantly depressed when Lv-HRE-Bcl-2-shRNA was combined with Lv-P53-shRNA or Lv-caspase3-shRNA transduction in a hypoxic environment. These results suggest that HRE-mediated Bcl-2 inhibition can effectively attenuate hypoxia-induced apoptosis resistance in PMVECs by downregulating Bcl-2 expression and upregulating caspase-3 and P53 expression. This study therefore reveals critical insight into potential therapeutic targets for treating PAH.
authors.affiliation: Department of Anesthesiology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Xuhui District, Shanghai, 200233, China.|Department of Anesthesiology, Dongfang Hospital, Tongji University, Shanghai, 200120, China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Anesthesiology, Dongfang Hospital, Tongji University, Shanghai, 200120, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Department of Anesthesiology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Xuhui District, Shanghai, 200233, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Department of Anesthesiology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Xuhui District, Shanghai, 200233, China.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Anesthesiology, Dongfang Hospital, Tongji University, Shanghai, 200120, China.
authors.forename: Yuchun
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Department of Anesthesiology, Dongfang Hospital, Tongji University, Shanghai, 200120, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Ji
authors.affiliation: Department of Anesthesiology, Dongfang Hospital, Tongji University, Shanghai, 200120, China.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Anesthesiology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Xuhui District, Shanghai, 200233, China. yingchuan.li@sjtu.edu.cn.
authors.forename: Yingchuan
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D015687:Cell Hypoxia; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation; D005822:Genetic Vectors / Q000737:chemistry / Q000378:metabolism; D006973:Hypertension / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016086:Lentivirus / Q000235:genetics / Q000378:metabolism; D008168:Lung / Q000098:blood supply / Q000473:pathology; D008297:Male; D016686:Monocrotaline; D061251:Primary Cell Culture; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D011651:Pulmonary Artery / Q000378:metabolism / Q000473:pathology; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020218:Response Elements; D015398:Signal Transduction; D014161:Transduction, Genetic; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; D016686:Monocrotaline; C505410:Casp3 protein, rat; D053148:Caspase 3
keywords: Bcl-2; Gene regulation; Hypoxia response element; Pulmonary microvascular endothelial cells