Carbon Monoxide and Nitric Oxide Suppress the Hypoxic Induction of Vascular Endothelial Growth Factor Gene via the 5′ Enhancer*
- Yuxiang Liu‡§,
- Helen Christou‡¶,
- Toshisuke Morita‡,
- Erik Laughner‖,
- Gregg L. Semenza‖** and
- Stella Kourembanas‡¶‡
- From the ‡Division of Developmental and Newborn Biology and ¶Division of Newborn Medicine, Department of Medicine, Children’s Hospital, Harvard Medical School, Boston, Massachusetts 02115 and the ‖Center for Medical Genetics, Departments of Pediatrics and Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
Abstract
Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis and blood vessel remodeling. Its expression is up-regulated in vascular smooth muscle cells by a number of conditions, including hypoxia. Hypoxia increases the transcriptional rate of VEGF via a 28-base pair enhancer located in the 5′-upstream region of the gene. The gas molecules nitric oxide (NO) and carbon monoxide (CO) are important vasodilating agents. We report here that these biological molecules can suppress the hypoxia-induced production of VEGF mRNA and protein in smooth muscle cells. In transient expression studies, both NO and CO inhibited the ability of the hypoxic enhancer we have previously identified to activate gene transcription. Furthermore, electrophoretic mobility shift assays indicated decreased binding of hypoxia-inducible factor 1 (HIF-1) to this enhancer by nuclear proteins isolated from CO-treated cells, although HIF-1 protein levels were unaffected by CO. Given that both CO and NO activate guanylyl cyclase to produce cGMP and that a cGMP analog (8-Br-cGMP) showed a similar suppressive effect on the hypoxic induction of the VEGF enhancer, we speculate that the suppression of VEGF by these two gas molecules occurs via a cyclic GMP-mediated pathway.
Footnotes
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↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵§ Supported by an Individual National Research Service Award HL-09008.
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↵** Supported by the American Heart Association and by National Institutes of Health Grants R01 DK39869 and R01 HL55338. Established Investigator of the American Heart Association.
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↵‡ Supported by the American Heart Association and by National Institutes of Health Grants SCOR 1P50 HL56398 and R01 HL55454. To whom correspondence should be addressed: Children’s Hospital, 300 Longwood Ave., Enders 9, Boston, MA 02115.
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↵1 The abbreviations used are: ET-1, endothelin-1; PDGF-B, platelet-derived growth factor-B; VEGF, vascular endothelial growth factor; NO, nitric oxide; CO, carbon monoxide; HO-1, heme oxygenase-1; HIF-1, hypoxia-inducible factor 1; BPAEC, bovine pulmonary artery endothelial cells; RASMC, rat aortic smooth muscle cells; SnPP-9, tin protoporphyrin IX; Hb, hemoglobin; GSNO,S-nitrosoglutathione; bp, base pair(s); CAT, chloramphenicol acetyltransferase.
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- Received January 13, 1998.
- Revision received April 6, 1998.
- The American Society for Biochemistry and Molecular Biology, Inc.
