title: Endothelium-derived hyperpolarizing factor synthase (Cytochrome P450 2C9) is a functionally significant source of reactive oxygen species in coronary arteries.
abstract: In the porcine coronary artery, a cytochrome P450 (CYP) isozyme homologous to CYP 2C8/9 has been identified as an endothelium-derived hyperpolarizing factor (EDHF) synthase. As some CYP enzymes are reported to generate reactive oxygen species (ROS), we hypothesized that the coronary EDHF synthase may modulate vascular homeostasis by the simultaneous production of ROS and epoxyeicosatrienoic acids. In bradykinin-stimulated coronary arteries, antisense oligonucleotides against CYP 2C almost abolished EDHF-mediated responses but potentiated nitric oxide (NO)-mediated relaxation. The selective CYP 2C9 inhibitor sulfaphenazole and the superoxide anion (O(2-)) scavengers Tiron and nordihydroguaretic acid also induced a leftward shift in the NO-mediated concentration-relaxation curve to bradykinin. CYP activity and O(2-) production, determined in microsomes prepared from cells overexpressing CYP 2C9, were almost completely inhibited by sulfaphenazole. Sulfaphenazole did not alter the activity of either CYP 2C8, the leukocyte NADPH oxidase, or xanthine oxidase. ROS generation in coronary artery rings, visualized using either ethidium or dichlorofluorescein fluorescence, was detected under basal conditions. The endothelial signal was attenuated by CYP 2C antisense treatment as well as by sulfaphenazole. In isolated coronary endothelial cells, bradykinin elicited a sulfaphenazole-sensitive increase in ROS production. Although 11,12 epoxyeicosatrienoic acid attenuated the activity of nuclear factor-kappaB in cultured human endothelial cells, nuclear factor-kappaB activity was enhanced after the induction or overexpression of CYP 2C9, as was the expression of vascular cell adhesion molecule-1. These results suggest that a CYP isozyme homologous to CYP 2C9 is a physiologically relevant generator of ROS in coronary endothelial cells and modulates both vascular tone and homeostasis.
authors.affiliation: Institut für Kardiovaskuläre Physiologie, Universität, Frankfurt, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Fleming
authors.forename: U R
authors.initials: UR
authors.lastname: Michaelis
authors.forename: D
authors.initials: D
authors.lastname: Bredenkötter
authors.forename: B
authors.initials: B
authors.lastname: Fisslthaler
authors.forename: F
authors.initials: F
authors.lastname: Dehghani
authors.forename: R P
authors.initials: RP
authors.lastname: Brandes
authors.forename: R
authors.initials: R
authors.lastname: Busse
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002460:Cell Line; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D000072467:Cytochrome P450 Family 2; D016373:DNA, Antisense / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D019255:NADPH Oxidases / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000502:physiology; D010105:Oxygenases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013426:Sulfaphenazole / Q000494:pharmacology; D013552:Swine; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects; D014969:Xanthine Oxidase / Q000187:drug effects / Q000378:metabolism
chemical_list: D016373:DNA, Antisense; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D013426:Sulfaphenazole; D009569:Nitric Oxide; C046783:11,12-epoxy-5,8,14-eicosatrienoic acid; D011189:Potassium Chloride; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; D000072467:Cytochrome P450 Family 2; C121871:cytochrome P-450 CYP2C8-34 (porcine); D014969:Xanthine Oxidase; D019255:NADPH Oxidases; D015126:8,11,14-Eicosatrienoic Acid; D001920:Bradykinin