title: Hypoxic but not anoxic stabilization of HIF-1alpha requires mitochondrial reactive oxygen species.
abstract: The molecular mechanisms by which cells detect hypoxia (1.5% O2), resulting in the stabilization of hypoxia-inducible factor 1alpha (HIF-1alpha) protein remain unclear. One model proposes that mitochondrial generation of reactive oxygen species is required to stabilize HIF-1alpha protein. Primary evidence for this model comes from the observation that cells treated with complex I inhibitors, such as rotenone, or cells that lack mitochondrial DNA (rho(0)-cells) fail to generate reactive oxygen species or stabilize HIF-1alpha protein in response to hypoxia. In the present study, we investigated the role of mitochondria in regulating HIF-1alpha protein stabilization under anoxia (0% O2). Wild-type A549 and HT1080 cells stabilized HIF-1alpha protein in response to hypoxia and anoxia. The rho(0)-A549 cells and rho(0)-HT1080 cells failed to accumulate HIF-1alpha protein in response to hypoxia. However, both rho(0)-A549 and rho(0)-HT1080 were able to stabilize HIF-1alpha protein levels in response to anoxia. Rotenone inhibited hypoxic, but not anoxic, stabilization of HIF-1alpha protein. These results indicate that a functional electron transport chain is required for hypoxic but not anoxic stabilization of HIF-1alpha protein.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611, USA.
authors.forename: Clara
authors.initials: C
authors.lastname: Schroedl
authors.forename: David S
authors.initials: DS
authors.lastname: McClintock
authors.forename: G R Scott
authors.initials: GR
authors.lastname: Budinger
authors.forename: Navdeep S
authors.initials: NS
authors.lastname: Chandel
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D015687:Cell Hypoxia / Q000502:physiology*; D002460:Cell Line; D006224:Cricetinae; D017930:Genes, Reporter; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007700:Kinetics; D008168:Lung; D008928:Mitochondria / Q000502:physiology*; D010101:Oxygen Consumption; D017382:Reactive Oxygen Species / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D020545:Respiratory Mucosa / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D019459:Urothelium
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D014157:Transcription Factors; D000255:Adenosine Triphosphate