Faculty Collaboration Database

Rabbit aorta converts 15-HPETE to trihydroxyeicosatrienoic acids: potential role of cytochrome P450. Arch Biochem Biophys 2003 Dec 01;420(1):142-52

Date

11/19/2003

Pubmed ID

14622984

DOI

10.1016/j.abb.2003.09.026

Scopus ID

2-s2.0-0242690352 (requires institutional sign-in at Scopus site)   24 Citations

Abstract

Previous work showed that rabbit aorta metabolizes arachidonic acid via 15-lipoxygenase to 15-hydroperoxyeicosatetraenoic acid (15-HPETE), which undergoes an enzymatic rearrangement to 11-hydroxy-14,15-epoxyeicosatrienoic acid (11-H-14,15-EETA) and 15-hydroxy-11,12-epoxyeicosatrienoic acid (15-H-11,12-EETA). Hydrolysis of the epoxy group results in the formation of 11,14,15- and 11,12,15-trihydroxyeicosatrienoic acids (THETAs). Endothelial cells have several heme-containing enzymes including cytochromes P450 (CYP), nitric oxide synthase (eNOS), and prostacyclin (PGI(2)) synthase that catalyze the rearrangement of 15-HPETE to HEETAs. Incubation of arachidonic acid and 15-lipoxygenase, or 15-HPETE with rabbit aortic microsomes or rat liver microsomes, a rich source of CYP, resulted in the formation of a product that comigrated with THETAs and HEETAs on HPLC. Immunoblot analysis showed the presence of CYP2C8 and CYP2J2 in aortic tissue and when CYP2J2 or CYP2C8 was incubated with arachidonic acid and 15-lipoxygenase, the major products were 11,12,15- and 11,14,15-THETAs. Incubation of purified hematin, CYP2C11, eNOS or PGI(2) synthase enzymes with arachidonic acid and 15-lipoxygenase produced a different pattern of metabolites from rabbit aortic microsomes. Clotrimazole, a non-specific CYP inhibitor, and ebastine and terfenadone, specific CYP2J2 inhibitors, blocked the ability of aortic microsomes to produce THETAs while specific inhibitors of PGI(2) synthase, eNOS or CYP2C8/2C9 had no effect on THETA production. We suggest that a CYP, possibly CYP2J2, may function as the hydroperoxide isomerase converting 15-HPETE to HEETAs in rabbit vascular tissue. Further hydrolysis of the epoxy group of the HEETAs results in the formation of 11,12,15- and 11,14,15-THETAs. The HEETAs and THETAs are both vasodilators and may function as important regulators of vascular tone.

Author List

Pfister SL, Spitzbarth N, Zeldin DC, Lafite P, Mansuy D, Campbell WB

Authors

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

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

Animals
Aorta
Culture Techniques
Cytochrome P-450 Enzyme System
Female
Hydroxyeicosatetraenoic Acids
Leukotrienes
Lipid Peroxides
Male
Rabbits