Faculty Collaboration Database

Hydrogen peroxide inhibits cytochrome p450 epoxygenases: interaction between two endothelium-derived hyperpolarizing factors. Circ Res 2008 Jan 04;102(1):59-67

Date

11/03/2007

Pubmed ID

17975109

Pubmed Central ID

PMC2364729

DOI

10.1161/CIRCRESAHA.107.159129

Scopus ID

2-s2.0-37849017735 (requires institutional sign-in at Scopus site)   89 Citations

Abstract

The cytochrome P450 epoxygenase (CYP)-derived metabolites of arachidonic acid the epoxyeicosatrienoic acids (EETs) and hydrogen peroxide (H2O2) both function as endothelium-derived hyperpolarizing factors (EDHFs) in the human coronary microcirculation. However, the relative importance of and potential interactions between these 2 vasodilators remain unexplored. We identified a novel inhibitory interaction between CYPs and H2O2 in human coronary arterioles, where EDHF-mediated vasodilatory mechanisms are prominent. Bradykinin induced vascular superoxide and H2O2 production in an endothelium-dependent manner and elicited a concentration-dependent dilation that was reduced by catalase but not by 14,15-epoxyeicosa-5(Z)-enoic acid (EEZE), 6-(2-propargyloxyphenyl)hexanoic acid, sulfaphenazole, or iberiotoxin. However, in the presence of catalase, an inhibitory effect of these compounds was unmasked. In a tandem-bioassay preparation, application of bradykinin to endothelium-intact donor vessels elicited dilation of downstream endothelium-denuded detectors that was partially inhibited by donor-applied catalase but not by detector-applied EEZE; however, EEZE significantly inhibited dilation in the presence of catalase. EET production by human recombinant CYP 2C9 and 2J2, 2 major epoxygenase isozymes expressed in human coronary arterioles, was directly inhibited in a concentration-dependent fashion by H2O2 in vitro, as observed by high-performance liquid chromatography (HPLC); however, EETs were not directly sensitive to oxidative modification. H2O2 inhibited dilation to arachidonic acid but not to 11,12-EET. These findings suggest that an inhibitory interaction exists between 2 EDHFs in the human coronary microcirculation. CYP epoxygenases are directly inhibited by H2O2, and this interaction may modulate vascular EET bioavailability.

Author List

Larsen BT, Gutterman DD, Sato A, Toyama K, Campbell WB, Zeldin DC, Manthati VL, Falck JR, Miura H

Author

William B. Campbell PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Arachidonic Acids
Arterioles
Biological Factors
Bradykinin
Catalase
Coronary Circulation
Cytochrome P-450 Enzyme Inhibitors
Endothelium, Vascular
Humans
Hydrogen Peroxide
Vasodilation