title: Regulation of hypoxia inducible factor-1 by nitric oxide in contrast to hypoxia in microvascular endothelium.
abstract: Hypoxia activates the transcription factor, hypoxia inducible factor-1 (HIF-1). Besides hypoxia, HIF-1 can be activated under normoxic conditions by nitric oxide. The signal transduction pathways involved in HIF-1alpha stabilization, HIF-1 DNA binding and transactivation by NO and hypoxia in microvascular endothelium remains unknown. We report that protein phosphorylation is involved in HIF-1 activation during hypoxia and NO. The phosphatidylinositol 3-kinase (PI-3K)/Akt pathway has differential effects on HIF-1 activation by hypoxia and NO. Our data indicate that the PI-3K/Akt pathway is insufficient for HIF-1alpha induction by hypoxia. The lipid and protein phosphatase activities of PTEN also appear to be involved in regulation of HIF-1alpha by NO.
authors.affiliation: Department of Internal Medicine, Virginia Commonwealth University, PO Box 980050, Richmond, VA 23298, USA. rnataraj@hsc.vcu.edu
authors.forename: Ramesh
authors.initials: R
authors.lastname: Natarajan
authors.forename: Bernard J
authors.initials: BJ
authors.lastname: Fisher
authors.forename: Alpha A
authors.initials: AA
authors.lastname: Fowler
mesh_terms: D002460:Cell Line; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D000860:Hypoxia; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008833:Microcirculation / Q000166:cytology; D009569:Nitric Oxide / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction; D014157:Transcription Factors; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D004268:DNA-Binding Proteins; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009569:Nitric Oxide; D009687:Nuclear Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D014157:Transcription Factors; C497442:HIF1A protein, human; C494918:AKT1 protein, human