Abstract
Cytochrome P450 (P450) eicosanoids regulate vascular tone, renal tubular transport, cellular proliferation, and inflammation. Both the CYP4A ω-hydroxylases, which catalyze 20-hydroxyeicosatetraenoic acid (20-HETE) formation, and soluble epoxide hydrolase (sEH), which catalyzes epoxyeicosatrienoic acid (EET) degradation to the dihydroxyeicosatrienoic acids (DHETs), are induced upon activation of peroxisome proliferator-activated receptor α (PPARα) by fatty acids and fibrates. In contrast, the CYP2C epoxygenases, which are responsible for EET formation, are repressed after fibrate treatment. We show here that P450 eicosanoids can bind to and activate PPARα and result in the modulation of PPARα target gene expression. In transactivation assays, 14,15-DHET, 11,2-EET, and 20-HETE were potent activators of PPARα. Gel shift assays showed that EETs, DHETs, and 20-HETE induced PPARα-specific binding to its cognate response element. Expression of apolipoprotein A-I was decreased 70% by 20-HETE, whereas apolipoprotein A-II expression was increased up to 3-fold by 11,12-EET, 14,15-DHET, and 20-HETE. In addition, P450 eicosanoids induced CYP4A1, sEH, and CYP2C11 expression, suggesting that they can regulate their own levels. Given that P450 eicosanoids have multiple cardiovascular effects, pharmacological modulation of their formation and/or degradation may yield therapeutic benefits.
Footnotes
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This work was supported by grants from the National Institutes of Health (Grants HL53994 to D.L.K. and GM31278 to J.R.F.). The UCSF Liver Center Core Facility (Cell and Tissue Biology) was supported by National Institutes of Health Grant P30 DK26743. V.Y.N was supported in part by predoctoral fellowships from the Pharmaceutical Research and Manufacturers of America Foundation (PhRMA) and the American Foundation for Pharmaceutical Education (AFPE).
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.106.013839.
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ABBREVIATIONS: P450, cytochrome P450; HETE, hydroxyeicosatetraenoic acid; EET, epoxyeicosatrienoic acid; sEH, soluble epoxide hydrolase; DHET, dihydroxyeicosatrienoic acid; PPAR, peroxisome proliferator-activated receptor; apoA, apolipoprotein A; PPRE, peroxisome proliferator response element; Wy-14,643, pirinixic acid, 4-chloro-6-(2,3-xylidino)-2-pyrimidinyl)thioacetic acid; 11,12-EEZE, 11,12-epoxyeicosa-8(Z)-enoic acid; T3, 3,3′,5-triiodo-l-thyronine; DMSO, dimethyl sulfoxide; RXRα, retinoid X receptor α; CPT, carnitine palmitoyl transferase; h, human; m, murine; PCR, polymerase chain reaction; MK-0767, ±-5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[(4-trifluoromethyl)phenyl]methyl]-benzamide.
- Received November 10, 2006.
- Accepted April 9, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
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