title: Nitric oxide and reactive oxygen species exert opposing effects on the stability of hypoxia-inducible factor-1alpha (HIF-1alpha) in explants of human pial arteries.
abstract: Hypoxia induces angiogenesis, partly through stabilization of hypoxia-inducible factor-1alpha (HIF-1alpha), leading to transcription of pro-angiogenic factors. Here we examined the regulation of HIF-1alpha by hypoxia and nitric oxide (NO) in explants of human cerebrovascular smooth muscle cells. Cells were treated with NO donors under normoxic or hypoxic (2% O2) conditions, followed by analysis of HIF-1alpha protein levels. Treatment with the NO donor sodium nitroprusside reduced levels of HIF-1alpha, whereas NO donors, NOC-18 and S-nitrosoglutathione, increased HIF-1alpha levels. SIN-1, which releases both NO and superoxide (O2*-), reduced HIF-1alpha levels, suggesting that inhibitory NO donors may elicit effects through peroxynitrite (ONOO*-). O2*- generation by xanthine/xanthine oxidase also reduced HIF-1alpha levels, confirming an inhibitory role for reactive oxygen species (ROS). Furthermore, superoxide dismutase increased HIF-1alpha levels, and the NO scavenger carboxy-PTIO reversed HIF-1alpha stabilization by NO donors. Effects on HIF-1alpha levels correlated with vascular endothelial growth factor transcription but did not affect HIF-1alpha transcription, as measured by RT-PCR and luciferase-reporter assays. The results indicate that HIF-1alpha is stabilized by agents that produce NO and reduce ROS but destabilized by agents that increase ROS, including O2*- and ONOO*-. Thus we propose that the effect of NO on HIF-1alpha signaling is critically dependent on the form of NO and the physiological environment of the responding cell.
authors.affiliation: Department of Pharmacology, University of Vermont, Given Bldg., 89 Beaumont Ave., Burlington, Vermont 05405, USA.
authors.forename: Theresa L
authors.initials: TL
authors.lastname: Wellman
authors.forename: Joshua
authors.initials: J
authors.lastname: Jenkins
authors.forename: Paul L
authors.initials: PL
authors.lastname: Penar
authors.forename: Bruce
authors.initials: B
authors.lastname: Tranmer
authors.forename: Rima
authors.initials: R
authors.lastname: Zahr
authors.forename: Karen M
authors.initials: KM
authors.lastname: Lounsbury
mesh_terms: D001158:Arteries / Q000166:cytology; D004795:Enzyme Stability / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008954:Models, Biological; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000494:pharmacology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D026422:S-Nitrosoglutathione / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C093285:NOC 18; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D013481:Superoxides; D009599:Nitroprusside; D019820:Xanthine; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; C002385:linsidomine; D008981:Molsidomine; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase