Normoxic Stabilization of Hypoxia-Inducible Factor-1 Expression and Activity: Redox-Dependent Effect of Nitrogen Oxides (original) (raw)
Research ArticleArticle
Molecular Pharmacology December 2000, 58 (6) 1197-1203; DOI: https://doi.org/10.1124/mol.58.6.1197
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-1α and HIF-1β. 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.
Footnotes
Received May 22, 2000.
Accepted August 28, 2000.
Send reprint requests to: Lisa A. Palmer Ph.D., Department of Anesthesiology, University of Virginia Health System, P.O. Box 800710, Charlottesville VA 22908-0710. E-mail: lap5w{at}virginia.edu
This work was supported by a Scientist Development grant from the American Heart Association to L.A.P, National Institutes of Health Grants RO1-HL37906 and RO1-GM49111 to R.A.J., and National Institutes of Health Grant RO1-HL59337–01A1 to B.G.
The American Society for Pharmacology and Experimental Therapeutics
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