Nitric oxide induces hypoxia-inducible factor 1 activation that is dependent on MAPK and phosphatidylinositol 3-kinase signaling.
Hypoxia-inducible factor-1 (HIF-1) is a master regulator of cellular adaptive responses to hypoxia. Levels of the HIF-1alpha subunit increase under hypoxic conditions. Exposure of cells to certain nitric oxide (NO) donors also induces HIF-1alpha expression under nonhypoxic conditions. We demonstrate that exposure of cells to the NO donor NOC18 or S-nitrosoglutathione induces HIF-1alpha expression and transcriptional activity. In contrast to hypoxia, NOC18 did not inhibit HIF-1alpha hydroxylation, ubiquitination, and degradation, indicating an effect on HIF-1alpha protein synthesis that was confirmed by pulse labeling studies. NOC18 stimulation of HIF-1alpha protein and HIF-1-dependent gene expression was blocked by treating cells with an inhibitor of the phosphatidylinositol 3-kinase or MAPK-signaling pathway. These inhibitors also blocked NOC18-induced phosphorylation of the translational regulatory proteins 4E-BP1, p70 S6 kinase, and eIF-4E, thus providing a mechanism for the modulation of HIF-1alpha protein synthesis. In addition, expression of a dominant-negative form of Ras significantly suppressed HIF-1 activation by NOC18. We conclude that the NO donor NOC18 induces HIF-1alpha synthesis under conditions of NO formation during normoxia and that hydroxylation of HIF-1alpha is not regulated by NOC18.
Human Stress Signal Research Center, National Institute of Advanced Industrial Science and Technology, IKEDA, Osaka, Japan 563-0053.
Kenji
K
Kasuno
Satoshi
S
Takabuchi
Kazuhiko
K
Fukuda
Shinae
S
Kizaka-Kondoh
Junji
J
Yodoi
Takehiko
T
Adachi
Gregg L
GL
Semenza
Kiichi
K
Hirota
D002460:Cell Line; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D006801:Humans; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D009687:Nuclear Proteins / Q000096:biosynthesis*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D026422:S-Nitrosoglutathione / Q000494:pharmacology; D014157:Transcription Factors
D004268:DNA-Binding Proteins; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C093285:NOC 18; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D009687:Nuclear Proteins; D014157:Transcription Factors; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D019869:Phosphatidylinositol 3-Kinases