Transcriptional regulation of the human soluble epoxide hydrolase gene EPHX2

Abstract

Soluble epoxide hydrolase (sEH) is a multifunctional protein encoded by the EPHX2 gene. The biological functions and enzyme kinetics of sEH have been extensively investigated, however, little is known about its transcriptional regulation and mechanisms of tissue specific expression. Here, a luciferase gene based reporter assay was used to identify the minimal promoter and cis regulatory elements of EPHX2. The minimal promoter was identified as a GC-rich region between nts −374 to +28 with respect to the putative transcriptional start site. A reporter plasmid carrying this minimal promoter showed higher or similar activities in comparison to a reporter plasmid carrying nts −5,974 to +28 of EPHX2 in 9 human cell lines that were tested. Sp1 binding sites that are involved in augmenting the minimal promoter activity of EPHX2 were identified by nested deletion analysis, site-specific mutation, electrophoretic mobility shift assay, and chromatin immunoprecipitation assay.

Soluble epoxide hydrolase is involved in the development of atherosclerosis and arterial neointima formation by regulating smooth muscle cell migration

“…sEH expression can be regulated by 15d-PGJ2, homocysteine, angiotensin II, and tyrosine nitration, as well as by peroxisome proliferator-activated receptor-␥ agonists (2,5,6,18,24). Our previous studies showed that sEH upregulation contributes to hypertension and cardiac hypertrophy (3,23).…”

“…The protocol of VSMCs infected with adenovirus sEH (Ad-sEH) or adenovirus-mediated green fluorescent protein (Ad-GFP) has been described elsewhere (3,18,23). The adenovirus was added to the medium and incubated for 24 h. The infection efficiency was detected by RT-PCR and Western blot analysis.…”

The Pharmacology of the Cytochrome P450 Epoxygenase/Soluble Epoxide Hydrolase Axis in the Vasculature and Cardiovascular Disease

“…Certainly, the exposure of mice to hypoxia for 3 weeks increased the expression of CYP2C29 and elicited pulmonary vascular remodeling (Pokreisz et al, 2006). Interestingly, the same procedure markedly attenuated the expression of the sEH in vivo and in vitro, most probably via altered binding of specificity protein 1 (Tanaka et al, 2008a) and c-Jun (Ai et al, 2007) to the sEH promoter. It was possible to make a causative link between remodeling and P450 activity because P450 inhibition attenuated the increase in pulmonary vascular muscularization observed over 1 week.…”

“…The sEH promoter contains several specificity protein 1 (Tanaka et al, 2008a) and activating protein 1 (AP-1) sites (Ai et al, 2007). Methylation of one of the former has been implicated in gene silencing , whereas the activation of AP-1 is implicated in the angiotensin IIinduced upregulation of the enzyme (Ai et al, 2007).…”

Soluble epoxide hydrolase plays an essential role in angiotensin II-induced cardiac hypertrophy

“…Our previous work indicated that AP-1 activation is involved in the transcriptional upregulation of sEH by Ang II in ECs (11). We previously reported that basal promoter activity of sEH varied in different types of cells, of which a proximal Sp1 binding site was critical (25). During the pathophysiological onset of hypertension, Ang II likely induces sEH via AP-1 activation in adult ventricular cardiomyocytes (11).…”