title: Over-expression of hypoxia-inducible factor-1 alpha in vitro protects the cardiac fibroblasts from hypoxia-induced apoptosis.
abstract: OBJECTIVE
  A great number of studies indicate that cardiac fibroblasts are essential for maintaining the structure and function of heart. Hypoxia-inducible factor-1 alpha (HIF-1α) is a central transcriptional regulator of hypoxic response. The present study examined whether over-expression of HIF-1α could prevent hypoxia-induced injury in neonatal rat cardiac fibroblasts and, if so, its possible molecular targets.
  
  
  METHODS
  Western blotting was used to detect protein level. MTT, electron microscopy, TUNEL staining and confocal microscopy were used to identify cell viability, cell apoptosis and intracellular calcium ([Ca]i) in cardiac fibroblasts, respectively.
  
  
  RESULTS
  When cardiac fibroblasts were exposed to hypoxia, HIF-1α protein in nuclei was transiently accumulated at 1 h, and then gradually degraded within 24 h of hypoxia exposure. Over-expression of HIF-1α enhanced nucleus expression of HIF-1α in cardiac fibroblasts, and significantly abolished the decrease of cell viability and cell apoptosis caused by 24-h hypoxia. Accordingly, hypoxia-induced Bax up-regulation, Bcl-2 down-regulation, caspase-3 activation and overload of [Ca]i in cardiac fibroblasts were reversed by HIF-1α over-expression, but were promoted by 30 μmol/l SC205346, a specific HIF-1α blocker.
  
  
  CONCLUSIONS
  Our results indicate that HIF-1α may act as a protective factor in the apoptotic process of cardiac fibroblasts and represent a potential therapeutic target for heart remodeling after hypoxia injury.
authors.affiliation: aDepartment of Pharmacy, the Daqing Oilfield General Hospital, Daqing, Heilongjiang bDepartment of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education) cDepartment of Surgery, the 2nd Affiliated Hospital, Harbin Medical University, Harbin, P.R. China *These authors contributed equally to this work.
authors.forename: Baofeng
authors.initials: B
authors.lastname: Yang
authors.forename: Kaiwen
authors.initials: K
authors.lastname: He
authors.forename: Fangfang
authors.initials: F
authors.lastname: Zheng
authors.forename: Lin
authors.initials: L
authors.lastname: Wan
authors.forename: Xiangru
authors.initials: X
authors.lastname: Yu
authors.forename: Xuelian
authors.initials: X
authors.lastname: Wang
authors.forename: Dan
authors.initials: D
authors.lastname: Zhao
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Bai
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Chu
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival; D004247:DNA / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000378:metabolism / Q000648:ultrastructure*; D005786:Gene Expression Regulation; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis / Q000235:genetics*; D020287:In Situ Nick-End Labeling; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D017202:Myocardial Ischemia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000648:ultrastructure*; D051381:Rats; D015398:Signal Transduction
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D004247:DNA; D053148:Caspase 3; D002118:Calcium