Risk of coronary artery disease associated with polymorphism of the cytochrome P450 epoxygenase CYP2J2

Abstract

Background: Cytochrome P450 (CYP) 2J2 is expressed in the vascular endothelium and metabolizes arachidonic acid to biologically active epoxyeicosatrienoic acids (EETs). The EETs are potent endogenous vasodilators and inhibitors of vascular inflammation. However, it is not known whether genetic polymorphisms of CYP2J2 are associated with increased cardiovascular risks.

Methods and results: All 9 exons of the CYP2J2 gene and its proximal promoter were sequenced in 132 patients to identify potential variants. Functional consequence of a single nucleotide polymorphism (SNP) in the promoter of CYP2J2 was further evaluated by use of transcription factor-binding and reporter assays. A total of 17 polymorphisms were identified. One of the most relevant polymorphisms in terms of frequency and functional importance is located at -50 (G-50T) in the proximal promoter of CYP2J2. Screening of 289 patients with coronary artery disease and 255 control subjects revealed 77 individuals with the G-50T SNP (17.3% of coronary artery disease patients, 10.6% of control subjects; P=0.026). The association of the G-50T polymorphism remained significant after adjustment for age, gender, and conventional cardiovascular risk factors (OR, 2.23; 95% CI, 1.04 to 4.79). The G-50T mutation resulted in the loss of binding of the Sp1 transcription factor to the CYP2J2 promoter and resulted in a 48.1+/-2.4% decrease in CYP2J2 promoter activity (P<0.01). Plasma concentrations of stable EET metabolites were significantly lower in individuals with the G-50T SNP.

Conclusions: A functionally relevant polymorphism of the CYP2J2 gene is independently associated with an increased risk of coronary artery disease.

Figure 1

Sense strand sequence of proximal CYP2J2 promoter with Sp1 binding sites. Position −50 corresponds to promoter polymorphism site for G-50T.

Figure 2

A, Electrophoretic mobility shift assay, using oligonucleotides with WT sequence at −50 Sp1 binding site or G-50T variant. Densitometry data are from 5 experiments. **P<0.001. B, Transient transfection of endothelial cells with CYP2J2-promoter-luciferase plasmid (pGL2 enhancer). CYP2J2 WT indicates reporter gene plasmid with WT promoter; CYP2J2 G-50T, same construct with G-50T variant. **P<0.01 vs CYP2J2 WT.

Figure 3

Plasma concentrations of stable EET metabolite DHET in individuals with (MT, n=8) or without (WT, n=7) G-50T polymorphism. Results are given for minimum, 25% quartile, median, 75% quartile, and maximum for each group. *P=0.028.