title: Normoxic stabilization of hypoxia-inducible factor-1 expression and activity: redox-dependent effect of nitrogen oxides.
abstract: Hypoxia-inducible factor-1 (HIF-1) is an essential transcription factor involved in the oxygen-dependent regulation of gene expression. Thiol groups in HIF-1 or in proteins that modify HIF-1 are conventional targets for regulation by nitric oxide (NO). Moreover, NO delivery to tissue by hemoglobin appears to be oxygen dependent. Therefore, the role NO plays in regulating HIF-1 activity and expression was examined. The 1-substituted diazen-1-ium-1, 2-diolate NOC-18 induced HIF-1 DNA-binding activity in normoxic bovine pulmonary artery endothelial cells and rat aortic smooth muscle cells in a time- and dose-dependent manner. Induction of HIF-1-binding activity was consistent with an increased expression of HIF-1 subunit proteins HIF-1alpha and HIF-1beta. The effect of NOC-18 on HIF-1 activity was blocked by cycloheximide, consistent with a post-transcriptional effect. NOC-18 induction of HIF-1 DNA-binding activity was not blocked with oxyhemoglobin, nor was it related to the rate of NO evolution, arguing against NO-mediation of the effect. Additionally, the effect of NOC-18 could not be mimicked by Angeli's salt, arguing against nitroxyl mediation. However, the NOC-18 effect could be reproduced by S-nitrosoglutathione (GSNO), an endogenous nitrosonium donor formed in the presence of deoxyhemoglobin. Furthermore, the GSNO effect could be reversed by dithiothreitol as well as acivicin, an inhibitor of GSNO bioactivation. Taken together, these results suggest that an S-nitrosylation reaction stabilizes HIF-1 protein expression and activity. We speculate that one signaling mechanism by which deoxyhemoglobin may activate HIF-1 involves NO.
authors.affiliation: University of Virginia Health System, Departments of Anesthesiology, Charlottesville, Virginia 22908-0710, USA. lap5w@virginia.edu
authors.forename: L A
authors.initials: LA
authors.lastname: Palmer
authors.forename: B
authors.initials: B
authors.lastname: Gaston
authors.forename: R A
authors.initials: RA
authors.lastname: Johns
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D004229:Dithiothreitol / Q000494:pharmacology; D004347:Drug Interactions; D015870:Gene Expression / Q000187:drug effects; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors; D009569:Nitric Oxide / Q000737:chemistry; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009589:Nitrogen Oxides / Q000378:metabolism; D009603:Nitroso Compounds / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D046988:Proteasome Endopeptidase Complex; D014157:Transcription Factors; D014158:Transcription, Genetic
chemical_list: D004268:DNA-Binding Proteins; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009097:Multienzyme Complexes; C093285:NOC 18; D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; D009603:Nitroso Compounds; D009687:Nuclear Proteins; D014157:Transcription Factors; D009569:Nitric Oxide; D004247:DNA; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D004229:Dithiothreitol