Repression of Heme Oxygenase-1 by Hypoxia in Vascular Endothelial Cells

• Published in: Biochemical and biophysical research communications Vol. 271; no. 3; pp. 665 - 671
• Main Authors: Nakayama, Masaharu, Takahashi, Kazuhiro, Kitamuro, Tomomi, Yasumoto, Ken-ichi, Katayose, Dai, Shirato, Kunio, Fujii-Kuriyama, Yoshiaki, Shibahara, Shigeki
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 19.05.2000
• Subjects: bilirubin; Cell Hypoxia; Cells, Cultured; cobalt; Cobalt - pharmacology; cobalt chloride; Deferoxamine - pharmacology; desferrioxamine; DNA-Binding Proteins - pharmacology; endothelial cells; Gene Expression Regulation, Enzymologic - drug effects; heme; Heme Oxygenase (Decyclizing) - genetics; Heme Oxygenase (Decyclizing) - metabolism; Heme Oxygenase-1; Humans; hypoxia-inducible factor; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Membrane Proteins; Muscle, Smooth, Vascular - enzymology; Nuclear Proteins - analysis; Nuclear Proteins - pharmacology; Oxygen - metabolism; oxygen sensor; RNA, Messenger - metabolism; stress response; Transcription Factors; endothelial cells; desferrioxamine; stress response; heme; bilirubin; oxygen sensor; cobalt; hypoxia-inducible factor
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.2000.2683

Heme oxygenase 1 (HO-1), a rate-limiting enzyme in heme catabolism, has been reported to be induced by hypoxia. Unexpectedly, here we show that expression of HO-1 mRNA is repressed by hypoxia in primary cultures of human umbilical vein endothelial cells (HUVECs), but is increased by cobalt chloride (CoCl2) that is known to mimic hypoxia. Under the culture conditions used, the DNA-binding and transactivation activities of hypoxia-inducible factor 1 were increased in HUVECs by hypoxia or CoCl2. Therefore, hypoxia and cobalt showed opposing effects on HO-1 mRNA expression, despite activation of hypoxia-inducible factor 1. The half-life of HO-1 mRNA was not changed by hypoxia, but was significantly prolonged by CoCl2. Hypoxia also represses HO-1 mRNA expression in human coronary artery endothelial cells and astrocytes. The repression of HO-1 expression may represent the adaptation to hypoxia in certain cell types.