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Watanabe S, Souza FDC, Kusumoto I, Shen Q, Nitin N, Lein PJ, Taha AY. Intraperitoneally injected d11-11(12)-epoxyeicosatrienoic acid is rapidly incorporated and esterified within rat plasma and peripheral tissues but not the brain. Prostaglandins Leukot Essent Fatty Acids 2024; 202:102622. [PMID: 38954932 DOI: 10.1016/j.plefa.2024.102622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/14/2024] [Accepted: 05/14/2024] [Indexed: 07/04/2024]
Abstract
Epoxyeicosatrienoic acids (EpETrEs) are bioactive lipid mediators of arachidonic acid cytochrome P450 oxidation. In vivo, the free (unbound) form of EpETrEs regulate multiple processes including blood flow, angiogenesis and inflammation resolution. Free EpETrEs are thought to rapidly degrade via soluble epoxide hydrolase (sEH); yet, in many tissues, the majority of EpETrEs are esterified to complex lipids (e.g. phospholipids) suggesting that esterification may play a major role in regulating free, bioactive EpETrE levels. This hypothesis was tested by quantifying the metabolism of intraperitoneally injected free d11-11(12)-Epoxyeicosatrienoic acid (d11-11(12)-EpETrE) in male and female rats. Plasma and tissues (liver, adipose and brain) were obtained 3 to 4 min later and assayed for d11-11(12)-EpETrE and its sEH metabolite, d11-11,12-dihydroxyeicosatrienoic acid (d11-11,12-diHETrE) in both the free and esterified lipid fractions. In both males and females, the majority of injected tracer was recovered in liver followed by plasma and adipose. No tracer was detected in the brain, indicating that brain levels are maintained by endogenous synthesis from precursor fatty acids. In plasma, liver, and adipose, the majority (>54 %) of d11-11(12)-EpETrE was found esterified to phospholipids or neutral lipids (triglycerides and cholesteryl esters). sEH-derived d11-11,12-diHETrE was not detected in plasma or tissues, suggesting negligible conversion within the 3-4 min period post tracer injection. This study shows that esterification is the main pathway regulating free 11(12)-EpETrE levels in vivo.
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Affiliation(s)
- Sho Watanabe
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA; Food Function Analysis Laboratory, Graduate School of Agricultural Science, Tohoku University, Miyagi, 9800845, Japan
| | - Felipe Da Costa Souza
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA
| | - Ibuki Kusumoto
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA; Food Function Analysis Laboratory, Graduate School of Agricultural Science, Tohoku University, Miyagi, 9800845, Japan
| | - Qing Shen
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA
| | - Nitin Nitin
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA; Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA; MIND Institute, University of California-Davis, 2825 50th Street, Sacramento, CA 95817
| | - Ameer Y Taha
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA; Center for Neuroscience, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA; West Coast Metabolomics Center, Genome Center, University of California-Davis, Davis, CA 95616, USA.
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Liang N, Harsch BA, Zhou S, Borkowska A, Shearer GC, Kaddurah-Daouk R, Newman JW, Borkowski K. Oxylipin transport by lipoprotein particles and its functional implications for cardiometabolic and neurological disorders. Prog Lipid Res 2024; 93:101265. [PMID: 37979798 DOI: 10.1016/j.plipres.2023.101265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 10/17/2023] [Accepted: 11/13/2023] [Indexed: 11/20/2023]
Abstract
Lipoprotein metabolism is critical to inflammation. While the periphery and central nervous system (CNS) have separate yet connected lipoprotein systems, impaired lipoprotein metabolism is implicated in both cardiometabolic and neurological disorders. Despite the substantial investigation into the composition, structure and function of lipoproteins, the lipoprotein oxylipin profiles, their influence on lipoprotein functions, and their potential biological implications are unclear. Lipoproteins carry most of the circulating oxylipins. Importantly, lipoprotein-mediated oxylipin transport allows for endocrine signaling by these lipid mediators, long considered to have only autocrine and paracrine functions. Alterations in plasma lipoprotein oxylipin composition can directly impact inflammatory responses of lipoprotein metabolizing cells. Similar investigations of CNS lipoprotein oxylipins are non-existent to date. However, as APOE4 is associated with Alzheimer's disease-related microglia dysfunction and oxylipin dysregulation, ApoE4-dependent lipoprotein oxylipin modulation in neurological pathologies is suggested. Such investigations are crucial to bridge knowledge gaps linking oxylipin- and lipoprotein-related disorders in both periphery and CNS. Here, after providing a summary of existent literatures on lipoprotein oxylipin analysis methods, we emphasize the importance of lipoproteins in oxylipin transport and argue that understanding the compartmentalization and distribution of lipoprotein oxylipins may fundamentally alter our consideration of the roles of lipoprotein in cardiometabolic and neurological disorders.
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Affiliation(s)
- Nuanyi Liang
- West Coast Metabolomics Center, Genome Center, University of California Davis, Davis, CA 95616, USA
| | - Brian A Harsch
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sitong Zhou
- Department of Pathology and Laboratory Medicine, University of California Davis, Davis, CA 95616, USA
| | - Alison Borkowska
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Gregory C Shearer
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Rima Kaddurah-Daouk
- Department of Psychiatry and Behavioral Sciences, Duke Institute for Brain Sciences and Department of Medicine, Duke University, Durham, NC, 27708, USA; Duke Institute of Brain Sciences, Duke University, Durham, NC, USA; Department of Medicine, Duke University, Durham, NC, USA
| | - John W Newman
- West Coast Metabolomics Center, Genome Center, University of California Davis, Davis, CA 95616, USA; Department of Nutrition, University of California - Davis, Davis, CA 95616, USA; Western Human Nutrition Research Center, United States Department of Agriculture - Agriculture Research Service, Davis, CA 95616, USA
| | - Kamil Borkowski
- West Coast Metabolomics Center, Genome Center, University of California Davis, Davis, CA 95616, USA.
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Qiu H, Li N, Liu JY, Harris TR, Hammock BD, Chiamvimonvat N. Soluble epoxide hydrolase inhibitors and heart failure. Cardiovasc Ther 2015; 29:99-111. [PMID: 20433684 DOI: 10.1111/j.1755-5922.2010.00150.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Cardiovascular disease remains one of the leading causes of death in the Western societies. Heart failure (HF) is due primarily to progressive myocardial dysfunction accompanied by myocardial remodeling. Once HF develops, the condition is, in most cases, irreversible and is associated with a very high mortality rate. Soluble epoxide hydrolase (sEH) is an enzyme that catalyzes the hydrolysis of epoxyeicosatrienoic acids (EETs), which are lipid mediators derived from arachidonic acid through the cytochrome P450 epoxygenase pathway. EETs have been shown to have vasodilatory, antiinflammatory, and cardioprotective effects. When EETs are hydrolyzed by sEH to corresponding dihydroxyeicosatrienoic acids, their cardioprotective activities become less pronounced. In line with the recent genetic study that has identified sEH as a susceptibility gene for HF, the sEH enzyme has received considerable attention as an attractive therapeutic target for cardiovascular diseases. Indeed, sEH inhibition has been demonstrated to have antihypertensive and antiinflammatory actions, presumably due to the increased bioavailability of endogenous EETs and other epoxylipids, and several potent sEH inhibitors have been developed and tested in animal models of cardiovascular disease including hypertension, cardiac hypertrophy, and ischemia/reperfusion injury. sEH inhibitor treatment has been shown to effectively prevent pressure overload- and angiotensin II-induced cardiac hypertrophy and reverse the pre-established cardiac hypertrophy caused by chronic pressure overload. Application of sEH inhibitors in several cardiac ischemia/reperfusion injury models reduced infarct size and prevented the progressive cardiac remodeling. Moreover, the use of sEH inhibitors prevented the development of electrical remodeling and ventricular arrhythmias associated with cardiac hypertrophy and ischemia/reperfusion injury. The data published to date support the notion that sEH inhibitors may represent a promising therapeutic approach for combating detrimental cardiac remodeling and HF.
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Affiliation(s)
- Hong Qiu
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, CA, USA Department of Veterans Affairs, Northern California Health Care System Mather, CA, USA Department of Entomology and UC Davis Cancer Center, University of California, Davis, CA, USA
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Alsaad AMS, Zordoky BNM, Tse MMY, El-Kadi AOS. Role of cytochrome P450-mediated arachidonic acid metabolites in the pathogenesis of cardiac hypertrophy. Drug Metab Rev 2013; 45:173-95. [PMID: 23600686 DOI: 10.3109/03602532.2012.754460] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A plethora of studies have demonstrated the expression of cytochrome P450 (CYP) and soluble epoxide hydrolase (sEH) enzymes in the heart and other cardiovascular tissues. In addition, the expression of these enzymes is altered during several cardiovascular diseases (CVDs), including cardiac hypertrophy (CH). The alteration in CYP and sEH expression results in derailed CYP-mediated arachidonic acid (AA) metabolism. In animal models of CH, it has been reported that there is an increase in 20-hydroxyeicosatetraenoic acid (20-HETE) and a decrease in epoxyeicosatrienoic acids (EETs). Further, inhibiting 20-HETE production by CYP ω-hydroxylase inhibitors and increasing EET stability by sEH inhibitors have been proven to protect against CH as well as other CVDs. Therefore, CYP-mediated AA metabolites 20-HETE and EETs are potential key players in the pathogenesis of CH. Some studies have investigated the molecular mechanisms by which these metabolites mediate their effects on cardiomyocytes and vasculature leading to pathological CH. Activation of several intracellular signaling cascades, such as nuclear factor of activated T cells, nuclear factor kappa B, mitogen-activated protein kinases, Rho-kinases, Gp130/signal transducer and activator of transcription, extracellular matrix degradation, apoptotic cascades, inflammatory cytokines, and oxidative stress, has been linked to the pathogenesis of CH. In this review, we discuss how 20-HETE and EETs can affect these signaling pathways to result in, or protect from, CH, respectively. However, further understanding of these metabolites and their effects on intracellular cascades will be required to assess their potential translation to therapeutic approaches for the prevention and/or treatment of CH and heart failure.
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Affiliation(s)
- Abdulaziz M S Alsaad
- Faculty of Pharmacy and Pharmaceutical Sciences, 2142J Katz Group-Rexall Center for Pharmacy and Health Research, University of Alberta, Edmonton, Alberta, Canada T6G 2E1
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Shahabi P, Siest G, Visvikis-siest S. Influence of inflammation on cardiovascular protective effects of cytochrome P450 epoxygenase-derived epoxyeicosatrienoic acids. Drug Metab Rev 2013; 46:33-56. [DOI: 10.3109/03602532.2013.837916] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Bruins MJ, Dane AD, Strassburg K, Vreeken RJ, Newman JW, Salem N, Tyburczy C, Brenna JT. Plasma oxylipin profiling identifies polyunsaturated vicinal diols as responsive to arachidonic acid and docosahexaenoic acid intake in growing piglets. J Lipid Res 2013; 54:1598-1607. [PMID: 23543770 DOI: 10.1194/jlr.m034918] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The dose-responsiveness of plasma oxylipins to incremental dietary intake of arachidonic acid (20:4n-6; ARA) and docosahexaenoic acid (22:6n-3; DHA) was determined in piglets. Piglets randomly received one of six formulas (n = 8 per group) from days 3 to 27 postnatally. Diets contained incremental ARA or incremental DHA levels as follows (% fatty acid, ARA/DHA): (A1) 0.1/1.0; (A2) 0.53/1.0; (A3-D3) 0.69/1.0; (A4) 1.1/1.0; (D1) 0.66/0.33; and (D2) 0.67/0.62, resulting in incremental intake (g/kg BW/day) of ARA: 0.07 ± 0.01, 0.43 ± 0.03, 0.55 ± 0.03, and 0.82 ± 0.05 at constant DHA intake (0.82 ± 0.05), or incremental intake of DHA: 0.27 ± 0.02, 0.49 ± 0.03, and 0.81 ± 0.05 at constant ARA intake (0.54 ± 0.04). Plasma oxylipin concentrations and free plasma PUFA levels were determined at day 28 using LC-MS/MS. Incremental dietary ARA intake dose-dependently increased plasma ARA levels. In parallel, ARA intake dose-dependently increased ARA-derived diols 5,6- and 14,15-dihydroxyeicosatrienoic acid (DiHETrE) and linoleic acid-derived 12,13-dihydroxyoctadecenoic acid (DiHOME), downstream metabolites of cytochrome P450 expoxygenase (CYP). The ARA epoxide products from CYP are important in vascular homeostatic maintenance. Incremental DHA intake increased plasma DHA and most markedly raised the eicosapentaenoic acid (EPA) metabolite 17,18-dihydroxyeicosatetraenoic acid (DiHETE) and the DHA metabolite 19,20-dihydroxydocosapentaenoic acid (DiHDPE). In conclusion, increasing ARA and DHA intake dose-dependently influenced endogenous n-6 and n-3 oxylipin plasma concentrations in growing piglets, although the biological relevance of these findings remains to be determined.
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Affiliation(s)
| | - Adrie D Dane
- Netherlands Metabolomics Centre (NMC), Leiden/Amsterdam Center for Drug Research (LACDR), Leiden University, Leiden, The Netherlands
| | - Katrin Strassburg
- Netherlands Metabolomics Centre (NMC), Leiden/Amsterdam Center for Drug Research (LACDR), Leiden University, Leiden, The Netherlands
| | - Rob J Vreeken
- Netherlands Metabolomics Centre (NMC), Leiden/Amsterdam Center for Drug Research (LACDR), Leiden University, Leiden, The Netherlands
| | - John W Newman
- Obesity and Metabolism Research Unit, US Department of Agriculture (USDA), Agricultural Research Service (ARS), Western Human Nutrition Research Center, Davis, CA
| | | | - Cynthia Tyburczy
- Division of Nutritional Sciences, Cornell University, Ithaca, NY
| | - J Thomas Brenna
- Division of Nutritional Sciences, Cornell University, Ithaca, NY.
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Sanders WG, Morisseau C, Hammock BD, Cheung AK, Terry CM. Soluble epoxide hydrolase expression in a porcine model of arteriovenous graft stenosis and anti-inflammatory effects of a soluble epoxide hydrolase inhibitor. Am J Physiol Cell Physiol 2012; 303:C278-90. [PMID: 22621785 PMCID: PMC3423029 DOI: 10.1152/ajpcell.00386.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 05/21/2012] [Indexed: 01/09/2023]
Abstract
Synthetic arteriovenous (AV) grafts, placed between an artery and vein, are used for hemodialysis but often fail due to stenosis, typically at the vein-graft anastomosis. This study recorded T lymphocyte and macrophage accumulation at the vein-graft anastomosis, suggesting a role for inflammation in stenosis development. Epoxyeicosatrienoic acids (EETs), products of cytochrome P-450 epoxidation of arachidonic acid, have vasculoprotective and anti-inflammatory effects including inhibition of platelet activation, cell migration, and adhesion. EETs are hydrolyzed by soluble epoxide hydrolase (sEH) to less active diols. The effects of a specific inhibitor of sEH (sEHI) on cytokine release from human monocytes and mouse bone marrow-derived macrophages (BMMΦ) from wild-type (WT) and sEH knockout (KO) animals were investigated. Expression of sEH protein increased over time at the anastomosis as evaluated by immunohistochemistry. Pre-exposure of adherent human monocytes to sEHI (5 μM) significantly inhibited lipopolysaccharide-induced release of monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-α and enhanced the EET-to-diol ratio. Release of MCP-1 from WT BMMΦ was significantly inhibited but release from sEH KO BMMΦ was not attenuated indicating the specificity of the sEHI. In contrast, sEHI did not inhibit the release of macrophage inflammatory protein-1 or interleukin-6. Nuclear translocation of NF-κB, as assessed by immunocytochemical staining, was not decreased with sEHI in monocytes, but the phosphorylation of JNK was completely abrogated, suggesting this pathway is the target of sEHI effects in monocytes. These results suggest that sEHI may be useful for inhibition of inflammation and subsequently stenosis in AV grafts.
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Affiliation(s)
- William G Sanders
- Department of Pharmaceutics, University of Utah, Salt Lake City, Utah 84112, USA
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Imig JD. Epoxides and soluble epoxide hydrolase in cardiovascular physiology. Physiol Rev 2012; 92:101-30. [PMID: 22298653 DOI: 10.1152/physrev.00021.2011] [Citation(s) in RCA: 272] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Epoxyeicosatrienoic acids (EETs) are arachidonic acid metabolites that importantly contribute to vascular and cardiac physiology. The contribution of EETs to vascular and cardiac function is further influenced by soluble epoxide hydrolase (sEH) that degrades EETs to diols. Vascular actions of EETs include dilation and angiogenesis. EETs also decrease inflammation and platelet aggregation and in general act to maintain vascular homeostasis. Myocyte contraction and increased coronary blood flow are the two primary EET actions in the heart. EET cell signaling mechanisms are tissue and organ specific and provide significant evidence for the existence of EET receptors. Additionally, pharmacological and genetic manipulations of EETs and sEH have demonstrated a contribution for this metabolic pathway to cardiovascular diseases. Given the impact of EETs to cardiovascular physiology, there is emerging evidence that development of EET-based therapeutics will be beneficial for cardiovascular diseases.
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Affiliation(s)
- John D Imig
- Department of Pharmacology and Toxicology, Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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Pang W, Li N, Ai D, Niu XL, Guan YF, Zhu Y. Activation of peroxisome proliferator-activated receptor-γ downregulates soluble epoxide hydrolase in cardiomyocytes. Clin Exp Pharmacol Physiol 2011; 38:358-64. [PMID: 21291492 DOI: 10.1111/j.1440-1681.2011.05492.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
1. The antidiabetic agents, thiazolidinediones (TZD), ligands for peroxisome proliferator-activated receptor-γ (PPARγ), have been reported to reduce cardiac hypertrophy. However, the underlying mechanism is still elusive. 2. We previously reported that soluble epoxide hydrolase (sEH) was specifically upregulated by angiotensin-II (AngII), which directly mediated AngII-induced cardiac hypertrophy. In the present study, we examined the role of sEH in PPARγ inhibiting AngII-induced cardiac hypertrophy. 3. The protein level of sEH was elevated in the left ventricle of AngII-infused Sprague-Dawley rats. Administration of the TZD rosiglitazone decreased this induction. In vitro, AngII upregulated the expression of sEH and hypertrophy markers, including atrial natriuretic factor and β-myosin heavy chain, in rat neonatal cardiomyocytes and H9c2 cells, which was attenuated by rosiglitazone and pioglitazone. An elevated level of sEH was also found in the left ventricle of heterozygous PPARγ-deficient mice. The effect of TZD on sEH level could be reversed by treatment with the PPARγ antagonists, GW9662 and BADGE, which suggests PPARγ activation. In elucidating the mechanisms by which PPARγ inhibited AngII-induced sEH expression, we found that rosiglitazone inhibited AngII-induced sEH promoter activity in H9c2 cells. In contrast, the activity of the human sEH 3'UTR was not affected by AngII and TZD. 4. Our results suggest that the protective role of PPARγ activation in AngII-induced cardiac hypertrophy is, at least in part, through downregulating sEH.
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Affiliation(s)
- Wei Pang
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Sciences of Education Ministry, Beijing, China
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Batchu SN, Lee SB, Qadhi RS, Chaudhary KR, El-Sikhry H, Kodela R, Falck JR, Seubert JM. Cardioprotective effect of a dual acting epoxyeicosatrienoic acid analogue towards ischaemia reperfusion injury. Br J Pharmacol 2011; 162:897-907. [PMID: 21039415 DOI: 10.1111/j.1476-5381.2010.01093.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Epoxyeicosatrienoic acids (EETs) are cytochrome P450 epoxygenase metabolites of arachidonic acid that are metabolized into dihydroxyepoxyeicosatrienoic acids (DHET) by soluble epoxide hydrolase (sEH). The current investigations were performed to examine the cardioprotective effects of UA-8 (13-(3-propylureido)tridec-8-enoic acid), a synthetic compound that possesses both EET-mimetic and sEH inhibitory properties, against ischaemia-reperfusion injury. EXPERIMENTAL APPROACH Hearts from C57BL/6 mice were perfused in Langendorff mode and subjected to ischaemia reperfusion. Mechanistic studies involved co-perfusing hearts with either 14,15-EEZE (a putative EET receptor antagonist), wortmannin or PI-103 (class-I PI3K inhibitor). H9c2 cells were utilized to investigate the protective effects against mitochondrial injury following anoxia reoxygenation. KEY RESULTS Perfusion of UA-8 significantly improved postischaemic left ventricular developed pressure (LVDP) and reduced infarction following ischaemia reperfusion compared with control and 11,12-EET. UA-7 (13-(2-(butylamino)-2-oxoacetamido)tridec-8(Z)-enoic acid), a compound lacking sEH inhibitory properties, also improved postischaemic LVDP, while co-perfusion with 14,15-EEZE, wortmannin or PI-103 attenuated the improved recovery. UA-8 prevented anoxia-reoxygenation induced loss of mitochondrial membrane potential and cell death in H9c2 cells, which was blocked by co-treatment of PI-103. CONCLUSIONS AND IMPLICATIONS UA-8 provides significant cardioprotection against ischaemia reperfusion injury. The effects are attributed to EETs mimetic properties, which limits mitochondrial dysfunction via class-I PI3K signalling.
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Affiliation(s)
- S N Batchu
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada
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Wagner K, Inceoglu B, Gill SS, Hammock BD. Epoxygenated fatty acids and soluble epoxide hydrolase inhibition: novel mediators of pain reduction. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:2816-24. [PMID: 20958046 PMCID: PMC3483885 DOI: 10.1021/jf102559q] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The soluble epoxide hydrolase (sEH) enzyme was discovered while investigating the metabolism of xenobiotic compounds in the Casida laboratory. However, an endogenous role of sEH is to regulate the levels of a group of potent bioactive lipids, epoxygenated fatty acids (EFAs), that have pleiotropic biological activities. The EFAs, in particular the arachidonic acid derived epoxy eicosatrienoic acids (EETs), are established autocrine and paracrine messengers. The most recently discovered outcome of inhibition of sEH and increased EFAs is their effects on the sensory system and in particular their ability to reduce pain. The inhibitors of sEH block both inflammatory and neuropathic pain. Elevation of EFAs, in both the central and peripheral nervous systems, blocks pain. Several laboratories have now published a number of potential mechanisms of action for the pain-reducing effects of EFAs. This paper provides a brief history of the discovery of the sEH enzyme and argues that inhibitors of sEH through several independent mechanisms display pain-reducing effects.
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Affiliation(s)
- Karen Wagner
- Department of Entomology and UC Davis Cancer Center, University of California Davis, Davis, CA 95616
| | - Bora Inceoglu
- Department of Entomology and UC Davis Cancer Center, University of California Davis, Davis, CA 95616
| | - Sarjeet S. Gill
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, CA 92521
| | - Bruce D. Hammock
- Department of Entomology and UC Davis Cancer Center, University of California Davis, Davis, CA 95616
- To whom correspondence should be addressed: Dr. Bruce D. Hammock Department of Entomology University of California Davis One Shields Ave. Davis, CA 95616 Tel: 530-751-7519 Fax: 530-752-1537
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12
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Li N, Liu JY, Qiu H, Harris TR, Sirish P, Hammock BD, Chiamvimonvat N. Use of metabolomic profiling in the study of arachidonic acid metabolism in cardiovascular disease. CONGESTIVE HEART FAILURE (GREENWICH, CONN.) 2011; 17:42-6. [PMID: 21272227 PMCID: PMC3583533 DOI: 10.1111/j.1751-7133.2010.00209.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Arachidonic acid is one of the pivotal signaling molecules associated with inflammation, pain and homeostatic function. Drugs specifically targeting these signaling pathways represent more than 25% of annual pharmaceutical sales worldwide. However, chronic administration of nonsteroidal anti-inflammatory drugs (NSAIDs) and rofecoxib (Vioxx), a potent cyclooxygenase-2 inhibitor, have been associated with adverse cardiovascular events. Understanding the possible mechanisms underlying these adverse events is critical for evaluating the risks and benefits of this group of drugs and for development of safer drugs. Using a powerful metabolomics approach, 20-hydroxyeicosatetraenoic acid (20-HETE) was identified among many of arachidonic acid metabolic products as a likely culprit for adverse cardiovascular side effect associated with rofecoxib and NSAIDs. In addition, using a similar metabolomic approach, epoxyeicosatrienoic acids (EETs), which are lipid mediators derived from arachidonic acid through the cytochrome P450 epoxygenase pathway, have been shown to exhibit cardioprotective effects in a murine myocardial infarction (MI) model. Inhibitors of the soluble epoxide hydrolase increase titers of epoxy fatty acids and both block and reverse cardiac hypertrophy in rodent models. These highly potent, orally available compounds may be promising for treating heart failure and other cardiovascular disease. In this review, we will summarize some of the recent advances using metabolomic profiling to gain insights into the involvement of arachidonic acid pathways in cardiovascular disease.
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Affiliation(s)
- Ning Li
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, CA
| | - Jun-Yan Liu
- Department of Entomology and UC Davis Cancer Center, University of California, Davis, CA
| | - Hong Qiu
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, CA
| | - Todd R. Harris
- Department of Entomology and UC Davis Cancer Center, University of California, Davis, CA
| | - Padmini Sirish
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, CA
| | - Bruce D. Hammock
- Department of Entomology and UC Davis Cancer Center, University of California, Davis, CA
| | - Nipavan Chiamvimonvat
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, CA
- Department of Veterans Affairs, Northern California Health Care System Mather, CA
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Bochkov VN, Oskolkova OV, Birukov KG, Levonen AL, Binder CJ, Stöckl J. Generation and biological activities of oxidized phospholipids. Antioxid Redox Signal 2010; 12:1009-59. [PMID: 19686040 PMCID: PMC3121779 DOI: 10.1089/ars.2009.2597] [Citation(s) in RCA: 419] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glycerophospholipids represent a common class of lipids critically important for integrity of cellular membranes. Oxidation of esterified unsaturated fatty acids dramatically changes biological activities of phospholipids. Apart from impairment of their structural function, oxidation makes oxidized phospholipids (OxPLs) markers of "modified-self" type that are recognized by soluble and cell-associated receptors of innate immunity, including scavenger receptors, natural (germ line-encoded) antibodies, and C-reactive protein, thus directing removal of senescent and apoptotic cells or oxidized lipoproteins. In addition, OxPLs acquire novel biological activities not characteristic of their unoxidized precursors, including the ability to regulate innate and adaptive immune responses. Effects of OxPLs described in vitro and in vivo suggest their potential relevance in different pathologies, including atherosclerosis, acute inflammation, lung injury, and many other conditions. This review summarizes current knowledge on the mechanisms of formation, structures, and biological activities of OxPLs. Furthermore, potential applications of OxPLs as disease biomarkers, as well as experimental therapies targeting OxPLs, are described, providing a broad overview of an emerging class of lipid mediators.
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Affiliation(s)
- Valery N Bochkov
- Department of Vascular Biology and Thrombosis Research, Center for Biomolecular Medicine and Pharmacology, Medical University of Vienna, Vienna, Austria.
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14
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Corenblum MJ, Wise VE, Georgi K, Hammock BD, Doris PA, Fornage M. Altered Soluble Epoxide Hydrolase Gene Expression and Function and Vascular Disease Risk in the Stroke-Prone Spontaneously Hypertensive Rat. Hypertension 2008; 51:567-73. [DOI: 10.1161/hypertensionaha.107.102160] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Soluble epoxide hydrolase (sEH) metabolizes epoxyeicosatrienoic acids and represents a novel therapeutic target in cardiovascular disease treatment. We investigated the relationship among sequence variation in the sEH gene (Ephx2), sEH function, and risk of end-organ injury in strains of spontaneously hypertensive rat (SHRs) differing in their susceptibility to develop brain vascular disease. Brain Ephx2 expression was significantly lower in stroke-prone (SHR/A3) than in stroke-resistant (SHR/N) SHRs (5-fold;
P
<0.0001). Resequencing of the Ephx2 promoter in the 2 strains identified 3 polymorphisms that significantly influenced promoter transcriptional activity in vitro. Measurements of brain sEH enzyme activity and plasma levels of arachidonate and linoleate metabolites of sEH further suggested significant differences between the 2 strains. Ratios of epoxyoctadecenoic acids to dihydroxyoctadecenoic acids were significantly higher, indicating a lower sEH activity in SHR/A3 than in SHR/N (
P
<0.0001). Plasma dihydroxyeicosatrienoic acid levels were lower in SHR/A3 than in SHR/N (
P
<0.0001), but plasma epoxyeicosatrienoic acids levels were similar in the 2 strains. Association analysis of Ephx2 polymorphism in the F2 progeny of an SHR/A3×SHR/N cross showed that animals carrying the SHR/A3 allele of Ephx2 had a greater risk of stroke and associated urinary proteinuria than animals that do not. Investigation of patterns of allelic similarities and differences among multiple stroke-prone and stroke-resistant SHR substrains showed that Ephx2 belongs to a haplotype block shared among all of the stroke-prone but no stroke-resistant substrains. These data support a role for Ephx2 polymorphism on sEH gene expression and function and risk of end-organ injury in the stroke-prone SHR.
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Affiliation(s)
- Mandi J. Corenblum
- From the Brown Foundation Institute of Molecular Medicine (M.J.C., V.E.W., P.A.D., M.F.), University of Texas Health Science Center at Houston, and the Department of Entomology and Cancer Research Center (K.G., B.D.H.), University of California at Davis
| | - Vance E. Wise
- From the Brown Foundation Institute of Molecular Medicine (M.J.C., V.E.W., P.A.D., M.F.), University of Texas Health Science Center at Houston, and the Department of Entomology and Cancer Research Center (K.G., B.D.H.), University of California at Davis
| | - Katrin Georgi
- From the Brown Foundation Institute of Molecular Medicine (M.J.C., V.E.W., P.A.D., M.F.), University of Texas Health Science Center at Houston, and the Department of Entomology and Cancer Research Center (K.G., B.D.H.), University of California at Davis
| | - Bruce D. Hammock
- From the Brown Foundation Institute of Molecular Medicine (M.J.C., V.E.W., P.A.D., M.F.), University of Texas Health Science Center at Houston, and the Department of Entomology and Cancer Research Center (K.G., B.D.H.), University of California at Davis
| | - Peter A. Doris
- From the Brown Foundation Institute of Molecular Medicine (M.J.C., V.E.W., P.A.D., M.F.), University of Texas Health Science Center at Houston, and the Department of Entomology and Cancer Research Center (K.G., B.D.H.), University of California at Davis
| | - Myriam Fornage
- From the Brown Foundation Institute of Molecular Medicine (M.J.C., V.E.W., P.A.D., M.F.), University of Texas Health Science Center at Houston, and the Department of Entomology and Cancer Research Center (K.G., B.D.H.), University of California at Davis
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15
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Spector AA, Norris AW. Action of epoxyeicosatrienoic acids on cellular function. Am J Physiol Cell Physiol 2006; 292:C996-1012. [PMID: 16987999 DOI: 10.1152/ajpcell.00402.2006] [Citation(s) in RCA: 352] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epoxyeicosatrienoic acids (EETs), which function primarily as autocrine and paracrine mediators in the cardiovascular and renal systems, are synthesized from arachidonic acid by cytochrome P-450 epoxygenases. They activate smooth muscle large-conductance Ca(2+)-activated K(+) channels, producing hyperpolarization and vasorelaxation. EETs also have anti-inflammatory effects in the vasculature and kidney, stimulate angiogenesis, and have mitogenic effects in the kidney. Many of the functional effects of EETs occur through activation of signal transduction pathways and modulation of gene expression, events probably initiated by binding to a putative cell surface EET receptor. However, EETs are rapidly taken up by cells and are incorporated into and released from phospholipids, suggesting that some functional effects may occur through a direct interaction between the EET and an intracellular effector system. In this regard, EETs and several of their metabolites activate peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma, suggesting that some functional effects may result from PPAR activation. EETs are metabolized primarily by conversion to dihydroxyeicosatrienoic acids (DHETs), a reaction catalyzed by soluble epoxide hydrolase (sEH). Many potentially beneficial actions of EETs are attenuated upon conversion to DHETs, which do not appear to be essential under routine conditions. Therefore, sEH is considered a potential therapeutic target for enhancing the beneficial functions of EETs.
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Affiliation(s)
- Arthur A Spector
- Dept. of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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16
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Jiang H. Erythrocyte-derived epoxyeicosatrienoic acids. Prostaglandins Other Lipid Mediat 2006; 82:4-10. [PMID: 17164127 DOI: 10.1016/j.prostaglandins.2006.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 05/16/2006] [Accepted: 05/18/2006] [Indexed: 11/25/2022]
Abstract
Red blood cells (RBCs) are reservoirs for cis- and trans-epoxyeicosatrienoic acids (EETs) that can be released. The sources of EET release from RBCs include direct synthesis from arachidonic acid, peroxidation of phospholipids and EETs esterified into cellular phospholipids. The release of EETs from RBCs can be through cytosolic phospholipase A2 (PLA2), secretory PLA2 and other responses associated with ATP release from RBCs. The erythrocyte ATP, purinergic receptors, ATP-binding cassette transporters, PLA2 and cytoskeleton rearrangement may all participate in EET release in the microcirculatory deformation of RBCs. EETs are vasodilatory and are candidate endothelium-derived hyperpolarizing factors. Due to the anti-hypertensive, fibrinolytic, and anti-thrombotic properties of EETs, their release from RBCs is replete with implications for the control of circulation and rheological characteristics of the circulating blood.
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Affiliation(s)
- Houli Jiang
- Department of Pharmacology, New York Medical College, Valhalla, New York 10595, USA.
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17
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Abstract
The importance of endothelium-derived nitric oxide in coronary vascular regulation is well-established and the loss of this vasodilator compound is associated with endothelial dysfunction, tissue hypoperfusion and atherosclerosis. Numerous studies indicate that the endothelium produces another class of compounds, the epoxyeicosatrienoic acids (EETs), which may partially compensate for the loss of nitric oxide in cardiovascular disease. The EETs are endogenous lipids which are derived through the metabolism of arachidonic acid by cytochrome P450 epoxygenase enzymes. Also, EETs hyperpolarize vascular smooth muscle and induce dilation of coronary arteries and arterioles, and therefore may be endogenous mediators of coronary vasomotor tone and myocardial perfusion. In addition, EETs have been shown to inhibit vascular smooth muscle migration, decrease inflammation, inhibit platelet aggregation and decrease adhesion molecule expression, therefore representing an endogenous protective mechanism against atherosclerosis. Endogenous EETs are degraded to less active dihydroxyeicosatrienoic acids by soluble epoxide hydrolase. Pharmacological inhibition of soluble epoxide hydrolase has received considerable attention as a potential approach to enhance EET-mediated vascular protection, and several compounds have appeared promising in recent animal studies. The present review discusses the emerging role of EETs in coronary vascular function, as well as recent advancements in the development of pharmacological agents to enhance EET bioavailability.
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Affiliation(s)
- B T Larsen
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Veterans Administration Medical Center, Milwaukee, WI 53226, USA
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18
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Larsen BT, Miura H, Hatoum OA, Campbell WB, Hammock BD, Zeldin DC, Falck JR, Gutterman DD. Epoxyeicosatrienoic and dihydroxyeicosatrienoic acids dilate human coronary arterioles via BK(Ca) channels: implications for soluble epoxide hydrolase inhibition. Am J Physiol Heart Circ Physiol 2005; 290:H491-9. [PMID: 16258029 PMCID: PMC1456013 DOI: 10.1152/ajpheart.00927.2005] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are metabolized by soluble epoxide hydrolase (sEH) to form dihydroxyeicosatrienoic acids (DHETs) and are putative endothelium-derived hyperpolarizing factors (EDHFs). EDHFs modulate microvascular tone; however, the chemical identity of EDHF in the human coronary microcirculation is not known. We examined the capacity of EETs, DHETs, and sEH inhibition to affect vasomotor tone in isolated human coronary arterioles (HCAs). HCAs from right atrial appendages were prepared for videomicroscopy and immunohistochemistry. In vessels preconstricted with endothelin-1, three EET regioisomers (8,9-, 11,12-, and 14,15-EET) each induced a concentration-dependent dilation that was sensitive to blockade of large-conductance Ca2+-activated K+ (BK(Ca)) channels by iberiotoxin. EET-induced dilation was not altered by endothelial denudation. 8,9-, 11,12-, and 14,15-DHET also dilated HCA via activation of BK(Ca) channels. Dilation was less with 8,9- and 14,15-DHET but was similar with 11,12-DHET, compared with the corresponding EETs. Immunohistochemistry revealed prominent expression of cytochrome P-450 (CYP450) 2C8, 2C9, and 2J2, enzymes that may produce EETs, as well as sEH, in HCA. Inhibition of sEH by 1-cyclohexyl-3-dodecylurea (CDU) enhanced dilation caused by 14,15-EET but reduced dilation observed with 11,12-EET. DHET production from exogenous EETs was reduced in vessels pretreated with CDU compared with control, as measured by liquid chromatography electrospray-ionization mass spectrometry. In conclusion, EETs and DHETs dilate HCA by activating BK(Ca) channels, supporting a role for EETs/DHETs as EDHFs in the human heart. CYP450s and sEH may be endogenous sources of these compounds, and sEH inhibition has the potential to alter myocardial perfusion, depending on which EETs are produced endogenously.
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Affiliation(s)
- Brandon T. Larsen
- Departments of Pharmacology and Toxicology
- Cardiovascular Center, Medical College of Wisconsin and
| | - Hiroto Miura
- Medicine, and the
- Cardiovascular Center, Medical College of Wisconsin and
| | - Ossama A. Hatoum
- Medicine, and the
- Cardiovascular Center, Medical College of Wisconsin and
| | | | - Bruce D. Hammock
- Department of Entomology and Cancer Research Center, University of California, Davis, California
| | - Darryl C. Zeldin
- Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina; and
| | - John R. Falck
- Departments of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - David D. Gutterman
- Departments of Pharmacology and Toxicology
- Medicine, and the
- Cardiovascular Center, Medical College of Wisconsin and
- Veterans Affairs Medical Center, Milwaukee, Wisconsin
- Address for reprint requests and other correspondence: D. D. Gutterman, Northwestern Mutual Professor of Medicine, Senior Associate Dean for Research, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226 (e-mail: )
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19
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Fang X, Hu S, Xu B, Snyder GD, Harmon S, Yao J, Liu Y, Sangras B, Falck JR, Weintraub NL, Spector AA. 14,15-Dihydroxyeicosatrienoic acid activates peroxisome proliferator-activated receptor-alpha. Am J Physiol Heart Circ Physiol 2005; 290:H55-63. [PMID: 16113065 DOI: 10.1152/ajpheart.00427.2005] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Epoxyeicosatrienoic acids (EETs), lipid mediators synthesized from arachidonic acid by cytochrome P-450 epoxygenases, are converted by soluble epoxide hydrolase (SEH) to the corresponding dihydroxyeicosatrienoic acids (DHETs). Originally considered as inactive degradation products of EETs, DHETs have biological activity in some systems. Here we examined the capacity of EETs and DHETs to activate peroxisome proliferator-activated receptor-alpha (PPARalpha). We find that among the EET and DHET regioisomers, 14,15-DHET is the most potent PPARalpha activator in a COS-7 cell expression system. Incubation with 10 microM 14,15-DHET produced a 12-fold increase in PPARalpha-mediated luciferase activity, an increase similar to that produced by the PPARalpha agonist Wy-14643 (20 microM). Although 10 microM 14,15-EET produced a threefold increase in luciferase activity, this was abrogated by the SEH inhibitor dicyclohexylurea. 14-Hexyloxytetradec-5(Z)-enoic acid, a 14,15-EET analog that cannot be converted to a DHET, did not activate PPARalpha. However, PPARalpha was activated by 2-(14,15-epoxyeicosatrienoyl)glycerol, which was hydrolyzed and the released 14,15-EET converted to 14,15-DHET. COS-7 cells incorporated 14,15-[3H]DHET from the medium, and the cells also retained a small amount of the DHET formed during incubation with 14,15-[3H]EET. Binding studies indicated that 14,15-[3H]DHET binds to the ligand binding domain of PPARalpha with a Kd of 1.4 microM. Furthermore, 14,15-DHET increased the expression of carnitine palmitoyltransferase 1A, a PPARalpha-responsive gene, in transfected HepG2 cells. These findings suggest that 14,15-DHET, produced from 14,15-EET by the action of SEH, may function as an endogenous activator of PPARalpha.
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Affiliation(s)
- Xiang Fang
- Dept. of Biochemistry, Univ. of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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20
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Newman JW, Morisseau C, Hammock BD. Epoxide hydrolases: their roles and interactions with lipid metabolism. Prog Lipid Res 2005; 44:1-51. [PMID: 15748653 DOI: 10.1016/j.plipres.2004.10.001] [Citation(s) in RCA: 320] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The epoxide hydrolases (EHs) are enzymes present in all living organisms, which transform epoxide containing lipids by the addition of water. In plants and animals, many of these lipid substrates have potent biologically activities, such as host defenses, control of development, regulation of inflammation and blood pressure. Thus the EHs have important and diverse biological roles with profound effects on the physiological state of the host organisms. Currently, seven distinct epoxide hydrolase sub-types are recognized in higher organisms. These include the plant soluble EHs, the mammalian soluble epoxide hydrolase, the hepoxilin hydrolase, leukotriene A4 hydrolase, the microsomal epoxide hydrolase, and the insect juvenile hormone epoxide hydrolase. While our understanding of these enzymes has progressed at different rates, here we discuss the current state of knowledge for each of these enzymes, along with a distillation of our current understanding of their endogenous roles. By reviewing the entire enzyme class together, both commonalities and discrepancies in our understanding are highlighted and important directions for future research pertaining to these enzymes are indicated.
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Affiliation(s)
- John W Newman
- Department of Entomology, UCDavis Cancer Center, University of California, One Shields Avenue, Davis, CA 95616, USA
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21
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Fang X, Weintraub NL, McCaw RB, Hu S, Harmon SD, Rice JB, Hammock BD, Spector AA. Effect of soluble epoxide hydrolase inhibition on epoxyeicosatrienoic acid metabolism in human blood vessels. Am J Physiol Heart Circ Physiol 2004; 287:H2412-20. [PMID: 15284062 DOI: 10.1152/ajpheart.00527.2004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the effects of soluble epoxide hydrolase (sEH) inhibition on epoxyeicosatrienoic acid (EET) metabolism in intact human blood vessels, including the human saphenous vein (HSV), coronary artery (HCA), and aorta (HA). When HSV segments were perfused with 2 micromol/l 14,15-[3H]EET for 4 h, >60% of radioactivity in the perfusion medium was converted to 14,15-dihydroxyeicosatrienoic acid (DHET). Similar results were obtained with endothelium-denuded vessels. 14,15-DHET was released from both the luminal and adventitial surfaces of the HSV. When HSVs were incubated with 14,15-[3H]EET under static (no flow) conditions, formation of 14,15-DHET was detected within 15 min and was inhibited by the selective sEH inhibitors N,N'-dicyclohexyl urea and N-cyclohexyl-N'-dodecanoic acid urea (CUDA). Similarly, CUDA inhibited the conversion of 11,12-[3H]EET to 11,12-DHET by the HSV. sEH inhibition enhanced the uptake of 14,15-[3H]EET and facilitated the formation of 10,11-epoxy-16:2, a beta-oxidation product. The HCA and HA converted 14,15-[3H]EET to DHET, and this also was inhibited by CUDA. These findings in intact human blood vessels indicate that conversion to DHET is the predominant pathway for 11,12- and 14,15-EET metabolism and that sEH inhibition can modulate EET metabolism in vascular tissue.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Cells, Cultured
- Cyclohexanes/pharmacology
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Epoxide Hydrolases/antagonists & inhibitors
- Epoxide Hydrolases/metabolism
- Epoxy Compounds/metabolism
- Humans
- Hydroxyeicosatetraenoic Acids/pharmacokinetics
- Lauric Acids/pharmacology
- Lipid Metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Oxidation-Reduction
- Saphenous Vein/drug effects
- Saphenous Vein/enzymology
- Solubility
- Tritium
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Xiang Fang
- Dept. of Biochemistry, 4-403 BSB, Univ. of Iowa College of Medicine, Iowa City, IA 52242, USA.
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22
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Yu Z, Davis BB, Morisseau C, Hammock BD, Olson JL, Kroetz DL, Weiss RH. Vascular localization of soluble epoxide hydrolase in the human kidney. Am J Physiol Renal Physiol 2003; 286:F720-6. [PMID: 14665429 DOI: 10.1152/ajprenal.00165.2003] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Epoxyeicosatrienoic acids are cytochrome P-450 metabolites of arachidonic acid with multiple biological functions, including the regulation of vascular tone, renal tubular transport, cellular proliferation, and inflammation. Epoxyeicosatrienoic acids are converted by soluble epoxide hydrolase into the corresponding dihydroxyeicosatrienoic acids, and epoxyeicosatrienoic acid hydration is regarded as one mechanism whereby their biological effects are eliminated. Previous animal studies indicate that soluble epoxide hydrolase plays an important role in the regulation of renal eicosanoid levels and systemic blood pressure. To begin to elucidate the mechanism of these effects, we determined the cellular localization of soluble epoxide hydrolase in human kidney by examining biopsies taken from patients with a variety of non-end-stage renal diseases, as well as those without known renal disease. Immunohistochemical staining of acetone-fixed kidney biopsy samples revealed that soluble epoxide hydrolase was preferentially expressed in the renal vasculature with relatively low levels in the surrounding tubules. Expression of soluble epoxide hydrolase was evident in renal arteries of varying diameter and was localized mostly in the smooth muscle layers of the arterial wall. Western blot analysis and functional assays confirmed the expression of soluble epoxide hydrolase in the human kidney. There were no obvious differences in soluble epoxide hydrolase expression between normal and diseased human kidney tissue in the samples examined. Our results indicate that soluble epoxide hydrolase is present in the human kidney, being preferentially expressed in the renal vasculature, and support an essential role for this enzyme in renal hemodynamic regulation and its potential utility as a target for therapeutic intervention.
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Affiliation(s)
- Zhigang Yu
- Dept. of Biopharmaceutical Sciences, Univ. of California San Francisco, 513 Parnassus, Box 0446, San Francisco, CA 94143-0446, USA
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23
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Yaghi A, Bradbury JA, Zeldin DC, Mehta S, Bend JR, McCormack DG. Pulmonary cytochrome P-450 2J4 is reduced in a rat model of acute Pseudomonas pneumonia. Am J Physiol Lung Cell Mol Physiol 2003; 285:L1099-105. [PMID: 12882760 DOI: 10.1152/ajplung.00039.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously reported that the levels of epoxyeicosatrienoic acids (EETs) and 20-hydroxyeicosatetraenoic acid (20-HETE) are depressed in microsomes prepared from lungs of rats with acute Pseudomonas pneumonia. We also showed a potential role for cytochrome P-450 (CYP) metabolites of arachidonic acid (AA) in contractile responses of both normal pulmonary arteries and pulmonary arteries from rats with pneumonia. The CYP2J subfamily enzymes (endogenous source of EETs and HETEs) are constitutively expressed in human and rat lungs where they are localized in vascular smooth muscle and endothelium. The purpose of this study was to determine if CYP2J proteins are modified in pneumonia. Pseudomonas organisms were injected via a tracheostomy in the lungs of rats. Later (44 h), lungs were frozen, and microsomes were prepared from pneumonia and control rat lung homogenates. Lung microsomal proteins were then immunoblotted with anti-CYP2B1/2B2, anti-CYP4A, anti-CYP2J9pep2 (which reacts with rat CYP2J3), anti-CYP2J6pep1 (which reacts with rat CYP2J4), anti-CYP2J2pep4, or anti-CYP2J2pep3 (both of which react with all known CYP2J isozymes). Western blotting revealed a prominent 55-kDa band with anti-CYP2J2pep3, anti-CYP2J2pep4, and anti-CYP2J6pep1 (but not anti-CYP2J9pep2) that was reduced in pneumonia compared with control lung microsomes. The CYP2B bands (51-52 kDa) were less prominent and not different between pneumonia and control lungs. CYP4A proteins (20-HETE sources) were not detected in rat lung microsomes. Therefore, rat lung contains a protein with immunological characteristics similar to CYP2J4, and this CYP is reduced after pneumonia. We speculate that CYP2J (but not CYP2B) enzymes and their AA metabolic products (EETs) are involved in the modulation of pulmonary vascular tone in pneumonia in rats.
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Affiliation(s)
- Asma Yaghi
- AC Burton Vascular Biology Laboratory, Lawson Health Research Institute, Respirology, London Health Sciences Centre, Victoria Campus, London, Ontario N6A 4G5, Canada
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24
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Fang X, Weintraub NL, Spector AA. Differences in positional esterification of 14,15-epoxyeicosatrienoic acid in phosphatidylcholine of porcine coronary artery endothelial and smooth muscle cells. Prostaglandins Other Lipid Mediat 2003; 71:33-42. [PMID: 12749592 DOI: 10.1016/s0090-6980(03)00002-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are readily incorporated into phospholipids of smooth muscle cells (SMC) and endothelial cells (EC). Incorporation of EETs into intact porcine coronary arteries potentiates EC-dependent relaxation, but not vasorelaxation induced by agents that act solely on SMC. To explore the potential mechanisms responsible for this difference, porcine coronary artery SMC and EC preloaded with [3H]14,15-EET were treated with calcium ionophore A23187. Although the amount of EET incorporated into EC and SMC was similar, A23187 stimulated a five-fold increase in release of radioactivity from EC, but only a 21% increase in release from SMC. Thin layer chromatography (TLC) examination of cell lipids demonstrated that > 70% of the incorporated radioactivity was present in phosphatidylcholine (PC) in both SMC and BC. After treatment of EC PC with PLA2, TLC analysis indicated that approximately equal to 75% of radioactivity was present as free EET, and 25% of radioactivity was present as lyso-PC. Therefore, most of the 14,15-EET was esterified into the sn-2 position of PC in EC. However, in SMC, approximately equal to 70% of radioactivity was present as lyso-PC after PLA2 treatment, indicating that the EET was predominately esterified into the sn-1 position. In contrast, all of the 14,15-EET was esterified into the sn-2 position of PI in both EC and SMC. These results suggest that the preferential incorporation of 14,15-EET into the sn-1 position of PC in SMC may help to explain the greater retention of the compound in SMC, while incorporation into the sn-2 position of PC in EC may facilitate agonist-induced 14,15-EET release and potentiation of EC-dependent porcine coronary artery relaxation.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/chemistry
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Animals
- Calcimycin/pharmacology
- Cells, Cultured
- Coronary Vessels
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Esterification
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Phosphatidylcholines/chemistry
- Phosphatidylcholines/metabolism
- Swine
- Tritium
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Xiang Fang
- Department of Biochemistry, University of Iowa College of Medicine, 4-403 BSB, Iowa City, IA 52242, USA.
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25
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Davis BB, Thompson DA, Howard LL, Morisseau C, Hammock BD, Weiss RH. Inhibitors of soluble epoxide hydrolase attenuate vascular smooth muscle cell proliferation. Proc Natl Acad Sci U S A 2002; 99:2222-7. [PMID: 11842228 PMCID: PMC122346 DOI: 10.1073/pnas.261710799] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2001] [Indexed: 11/18/2022] Open
Abstract
Atherosclerosis, in its myriad incarnations the foremost killer disease in the industrialized world, is characterized by aberrant proliferation of vascular smooth muscle (VSM) cells in part as a result of the recruitment of inflammatory cells to the blood vessel wall. The epoxyeicosatrienoic acids are synthesized from arachidonic acid in a reaction catalyzed by the cytochrome P450 system and are vasoactive substances. Metabolism of these compounds by epoxide hydrolases results in the formation of compounds that affect the vasculature in a pleiotropic manner. As an outgrowth of our observations that urea inhibitors of the soluble epoxide hydrolase (sEH) reduce blood pressure in spontaneously hypertensive rats as well as the findings of other investigators that these compounds possess antiinflammatory actions, we have examined the effect of sEH inhibitors on VSM cell proliferation. We now show that the sEH inhibitor 1-cyclohexyl-3-dodecyl urea (CDU) inhibits human VSM cell proliferation in a dose-dependent manner and is associated with a decrease in the level of cyclin D1. In addition, cis-epoxyeicosatrienoic acid mimics the growth-suppressive activity of CDU; there is no evidence of cellular toxicity or apoptosis in CDU-treated cells when incubated with 20 microM CDU for up to 48 h. These results, in light of the antiinflammatory and antihypertensive properties of these compounds that have been demonstrated already, suggest that the urea class of sEH inhibitors may be useful for therapy for diseases such as hypertension and atherosclerosis characterized by exuberant VSM cell proliferation and vascular inflammation.
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Affiliation(s)
- Benjamin B Davis
- Division of Nephrology, Department of Internal Medicine, University of California, Davis, CA 95616, USA
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26
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Imig JD, Zhao X, Capdevila JH, Morisseau C, Hammock BD. Soluble epoxide hydrolase inhibition lowers arterial blood pressure in angiotensin II hypertension. Hypertension 2002; 39:690-4. [PMID: 11882632 DOI: 10.1161/hy0202.103788] [Citation(s) in RCA: 320] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) have antihypertensive properties and play a part in the maintenance of renal microvascular function. A novel approach to increase EET levels is to inhibit epoxide hydrolase enzymes that are responsible for conversion of biologically active EETs to dihydroxyeicosatrienoic acids (DHETs) that are void of effects on the preglomerular vasculature. We hypothesized that inhibition of soluble epoxide hydrolase (sEH) would lower blood pressure in angiotensin II (Ang II) hypertension. Rat renal cortical tissue was harvested and urine collected 2 weeks following implantation of an osmotic minipump containing Ang II (60 ng/min). Renal cortical sEH protein expression was significantly higher in Ang II hypertension compared with normotensive animals. Likewise, urinary 14,15-DHET levels were significantly increased in hypertensive compared with normotensive animals and averaged 8.1 +/- 1.3 and 2.7 +/- 1.1 ng/d; respectively. In additional experiments, the sEH inhibitor N-cyclohexyl-N-dodecyl urea (NCND; 3 mg/d) or vehicle (corn oil, 0.5 mL) was administered daily by intraperitoneal injection starting on day 10. Administration of NCND for 4 days lowered systolic blood pressure by 30 mm Hg in Ang II hypertensive animals, whereas the corn oil vehicle had no effect on blood pressure in normotensive or Ang II hypertensive animals. Measurement of blood pressure by indwelling arterial catheters in conscious animals with free movement in their cages confirmed that NCND had antihypertensive properties. Arterial blood pressure averaged 119 +/- 5 mm Hg in normotensive, 170 +/- 3 mm Hg in hypertensive and 149 +/- 10 mm Hg in NCND-treated, Ang II-infused animals. Administration of the potential metabolite of NCND, N-cyclohexylformamide to Ang II hypertensive rats did not lower the systolic blood pressure. These studies demonstrate that increased sEH expression in the Ang II hypertensive kidney leads to increased EET hydration. Moreover, sEH plays a role in the regulation of blood pressure, and inhibition of sEH during Ang II hypertension is antihypertensive.
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Affiliation(s)
- John D Imig
- Vascular Biology Center, Department of Physiology, Medical College of Georgia, Augusta, GA 30912-2500, USA.
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27
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Abstract
Recent studies have indicated that arachidonic acid is primarily metabolized by cytochrome P-450 (CYP) enzymes in the brain, lung, kidney, and peripheral vasculature to 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) and that these compounds play critical roles in the regulation of renal, pulmonary, and cardiac function and vascular tone. EETs are endothelium-derived vasodilators that hyperpolarize vascular smooth muscle (VSM) cells by activating K(+) channels. 20-HETE is a vasoconstrictor produced in VSM cells that reduces the open-state probability of Ca(2+)-activated K(+) channels. Inhibitors of the formation of 20-HETE block the myogenic response of renal, cerebral, and skeletal muscle arterioles in vitro and autoregulation of renal and cerebral blood flow in vivo. They also block tubuloglomerular feedback responses in vivo and the vasoconstrictor response to elevations in tissue PO(2) both in vivo and in vitro. The formation of 20-HETE in VSM is stimulated by angiotensin II and endothelin and is inhibited by nitric oxide (NO) and carbon monoxide (CO). Blockade of the formation of 20-HETE attenuates the vascular responses to angiotensin II, endothelin, norepinephrine, NO, and CO. In the kidney, EETs and 20-HETE are produced in the proximal tubule and the thick ascending loop of Henle. They regulate Na(+) transport in these nephron segments. 20-HETE also contributes to the mitogenic effects of a variety of growth factors in VSM, renal epithelial, and mesangial cells. The production of EETs and 20-HETE is altered in experimental and genetic models of hypertension, diabetes, uremia, toxemia of pregnancy, and hepatorenal syndrome. Given the importance of this pathway in the control of cardiovascular function, it is likely that CYP metabolites of arachidonic acid contribute to the changes in renal function and vascular tone associated with some of these conditions and that drugs that modify the formation and/or actions of EETs and 20-HETE may have therapeutic benefits.
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Affiliation(s)
- Richard J Roman
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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28
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Abstract
Since the initial reports that renal cytochrome P450 (CYP) enzymes can metabolize arachidonic acid to substances which affect arterial tone, it has become increasingly clear that CYP enzymes expressed within the cardiovascular system play a crucial role in the modulation of vascular homeostasis. There is strong evidence suggesting that the activation of a CYP epoxygenase in endothelial cells is an essential step in nitric oxide and prostacyclin-independent vasodilatation of several vascular beds, particularly in the heart and kidney. A smooth muscle CYP omega-hydroxylase, on the other hand, generates a vasoconstrictor eicosanoid that is central to the myogenic response. Moreover, CYP epoxygenase and omega-hydroxylase products, as well as CYP-derived reactive oxygen species, are intracellular signal transduction molecules involved in several signaling cascades affecting numerous cellular processes, including vascular cell proliferation and angiogenesis. This review summarizes the vascular effects of epoxyeicosatrienoic acids and 20-hydroxyeicosatetraenoic acid, both of which are CYP-derived metabolites of arachidonic acid, endogenously generated within endothelial and vascular smooth muscle cells. Although the link between CYP expression/activity and cardiovascular disease is currently tentative, the evidence being accumulated to suggest that CYP pathways are altered in animal models of hypertension and atherosclerosis can no longer be ignored. The development of selective pharmacological tools is, however, a prerequisite for the analysis of the involvement of specific CYP isoforms in the regulation of vascular homeostasis in human subjects.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/metabolism
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Animals
- Arachidonic Acid/metabolism
- Biological Factors/metabolism
- Cardiovascular System/drug effects
- Cardiovascular System/metabolism
- Cytochrome P-450 CYP4A
- Cytochrome P-450 Enzyme System/metabolism
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Epoxy Compounds/metabolism
- Epoxy Compounds/pharmacology
- Free Radicals/metabolism
- Homeostasis/drug effects
- Homeostasis/physiology
- Humans
- Hydroxyeicosatetraenoic Acids/metabolism
- Hydroxyeicosatetraenoic Acids/pharmacology
- Isoenzymes/metabolism
- Mixed Function Oxygenases/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Vasomotor System/drug effects
- Vasomotor System/metabolism
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Affiliation(s)
- I Fleming
- Institut für Kardiovaskuläre Physiologie, Klinikum der J.W.G.-Universität, Frankfurt am Main, Germany.
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29
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Fleming I, Busse R. Vascular cytochrome P450 in the regulation of renal function and vascular tone: EDHF, superoxide anions and blood pressure. Nephrol Dial Transplant 2001; 16:1309-11. [PMID: 11427614 DOI: 10.1093/ndt/16.7.1309] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- I Fleming
- Institut für Kardiovaskuläre Physiologie, Klinikum der J.W.Goethe-Universität, Frankfurt am Main, Germany
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30
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Maier KG, Henderson L, Narayanan J, Alonso-Galicia M, Falck JR, Roman RJ. Fluorescent HPLC assay for 20-HETE and other P-450 metabolites of arachidonic acid. Am J Physiol Heart Circ Physiol 2000; 279:H863-71. [PMID: 10924088 DOI: 10.1152/ajpheart.2000.279.2.h863] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study describes a fluorescent HPLC assay for measuring 20-hydroxyeicosatetraenoic acid (20-HETE) and other cytochrome P-450 metabolites of arachidonic acid in urine, tissue, and interstitial fluid. An internal standard, 20-hydroxyeicosa-6(Z),15(Z)-dienoic acid, was added to samples, and the lipids were extracted and labeled with 2-(2,3-naphthalimino)ethyl trifluoromethanesulfonate. P-450 metabolites were separated on a C18 reverse-phase HPLC column. Coelution and gas chromatography-mass spectrometry studies confirmed the identity of the 20-HETE peak. The 20-HETE peak can be separated from those for dihydroxyeicosatrienoic acids, other HETEs, and epoxyeicosatrienoic acids. Known amounts of 20-HETE were used to generate a standard curve (range 1-10 ng, r(2) = 0.98). Recovery of 20-HETE from urine averaged 95%, and the intra-assay variation was <5%. Levels of 20-HETE were measured in 100 microliter of urine and renal interstitial fluid or 0.1 mg of renal tissue. The assay was evaluated by studying the effects of 1-aminobenzotriazole (ABT) on the excretion of 20-HETE in rats. ABT reduced excretion of 20-HETE by >65% and inhibited the formation of 20-HETE by renal microsomes. The availability of this assay should facilitate work in this field.
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Affiliation(s)
- K G Maier
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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31
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Greene JF, Williamson KC, Newman JW, Morisseau C, Hammock BD. Metabolism of monoepoxides of methyl linoleate: bioactivation and detoxification. Arch Biochem Biophys 2000; 376:420-32. [PMID: 10775430 DOI: 10.1006/abbi.2000.1753] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Leukotoxin (ltx) and isoleukotoxin (iltx) methyl esters, are metabolites of methyl linoleic acid, an essential fatty acid. They have been associated with acute respiratory distress syndrome. The observed toxicity of ltx and iltx is, in fact, due to the metabolism of the epoxides to their corresponding diols by soluble epoxide hydrolase (sEH). Herein, we demonstrate that ltx/iltx are toxic in a time-dependent manner to human sEH expressing cells with a LT(50) of 10.6 +/- 0.8 h and that ltx and iltx have K(M) of 6.15 +/- 1.0 and 5. 17 +/- 0.56 microM, respectively, and V(max) of 2.67 +/- 0.04 and 1. 86 +/- 0.06 micromol/min/mg, respectively, which can be inhibited by sEH inhibitors. We show that four major metabolites of ltx/iltx are formed in our system, including ltx/iltx free acid, ltxd/iltxd, free acid, and phosphotidylcholine and phosphotidylethanolamine containing the carboxylic acid forms of both ltx/iltx and ltxd/iltxd, but that the only metabolite associated with toxicity is the carboxylic acid form of ltxd/iltxd, suggesting the involvement of cellular esterases. We demonstrate that a serine esterase inhibitor provides some protection from the toxicity of epoxy fatty esters to sEH expressing cells as do intercellular free sulfhydryls, but that this protection is not due to glutathione conjugation. With these data, we have proposed an extension of the metabolic pathway for ltx/iltx in eukaryotic cells.
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Affiliation(s)
- J F Greene
- Department of Entomology, University of California at Davis, Davis, California 95616, USA
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32
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Fang X, Weintraub NL, Stoll LL, Spector AA. Epoxyeicosatrienoic acids increase intracellular calcium concentration in vascular smooth muscle cells. Hypertension 1999; 34:1242-6. [PMID: 10601125 DOI: 10.1161/01.hyp.34.6.1242] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are cytochrome P450-derived metabolites of arachidonic acid. They are potent endogenous vasodilator compounds produced by vascular cells, and EET-induced vasodilation has been attributed to activation of vascular smooth muscle cell (SMC) K(+) channels. However, in some cells, EETs activate Ca(2+) channels, resulting in Ca(2+) influx and increased intracellular Ca(2+) concentration ([Ca(2+)](i)). We investigated whether EETs also can activate Ca(2+) channels in vascular SMC and whether the resultant Ca(2+) influx can influence vascular tone. The 4 EET regioisomers (1 micromol/L) increased porcine aortic SMC [Ca(2+)](i) by 52% to 81%, whereas arachidonic acid, dihydroxyeicosatrienoic acids, and 15-hydroxyeicosatetraenoic acid (1 micromol/L) produced little effect. The increases in [Ca(2+)](i) produced by 14,15-EET were abolished by removal of extracellular Ca(2+) and by pretreatment with verapamil (10 micromol/L), an inhibitor of voltage-dependent (L-type) Ca(2+) channels. 14,15-EET did not alter Ca(2+) signaling induced by norepinephrine and thapsigargin. When administered to porcine coronary artery rings precontracted with a thromboxane mimetic, 14,15-EET produced relaxation. However, when administered to rings precontracted with acetylcholine or KCl, 14,15-EET produced additional contractions. In rings exposed to 10 mmol/L KCl, a concentration that did not affect resting ring tension, 14,15-EET produced small contractions that were abolished by EGTA (3 mmol/L) or verapamil (10 micromol/L). These observations indicate that 14,15-EET enhances [Ca(2+)](i) influx in vascular SMC through voltage-dependent Ca(2+) channels. This 14,15-EET-induced increase in [Ca(i)(2+)] can produce vasoconstriction and therefore may act to modulate EET-induced vasorelaxation.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/metabolism
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Cell Membrane Permeability/drug effects
- Cell Membrane Permeability/physiology
- Cells, Cultured
- Chelating Agents/pharmacology
- Coronary Vessels/drug effects
- Coronary Vessels/metabolism
- Dose-Response Relationship, Drug
- In Vitro Techniques
- Intracellular Fluid/drug effects
- Intracellular Fluid/metabolism
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Structure-Activity Relationship
- Swine
- Vasoconstrictor Agents/pharmacology
- Vasodilator Agents/pharmacology
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Affiliation(s)
- X Fang
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City 52242, USA.
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33
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Fang X, Moore SA, Stoll LL, Rich G, Kaduce TL, Weintraub NL, Spector AA. 14,15-Epoxyeicosatrienoic acid inhibits prostaglandin E2 production in vascular smooth muscle cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:H2113-21. [PMID: 9843811 DOI: 10.1152/ajpheart.1998.275.6.h2113] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
14,15-Epoxyeicosatrienoic acid (EET), a cytochrome P-450 epoxygenase product of arachidonic acid (AA), reduced PGE2 formation by 40-75% in porcine aortic and murine brain microvascular smooth muscle cells. The inhibition was reversed 6-10 h after removal of 14,15-EET from the medium and was regioisomeric specific; 8,9-EET produced a smaller effect, whereas 11,12- and 5,6-EET were ineffective. Although the cells converted 14,15-EET to 14, 15-dihydroxyeicosatrienoic acid (14,15-DHET), 14,15-DHET did not inhibit PGE2 formation, and the 14,15-EET-induced inhibition was potentiated by 4-phenylchalcone oxide, an epoxide hydrolase inhibitor. The inhibition occurred when substrate amounts of AA were used and was not accompanied by enhanced production of other PGs, suggesting an effect on PGH synthase; however, in murine cells, 14, 15-EET did not reduce PGH synthase mRNA or protein. Moreover, the 14, 15-EET-induced decrease in PGE2 production was overcome by increasing the concentration of AA, but not oleic acid (which is not a substrate for PGH synthase). These findings suggest that 14,15-EET competitively inhibits PGH synthase activity in vascular smooth muscle cells. The 14,15-EET-induced inhibition of PGE2 production resulted in potentiation of platelet-derived growth factor-induced smooth muscle cell proliferation, suggesting that the competitive inhibition of PGH synthase by 14,15-EET can affect growth responses in smooth muscle cells.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Animals
- Aorta/cytology
- Aorta/drug effects
- Aorta/metabolism
- Cell Division/drug effects
- Cells, Cultured
- Cerebrovascular Circulation/physiology
- Dinoprostone/antagonists & inhibitors
- Hydroxyeicosatetraenoic Acids/pharmacology
- Microcirculation/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Platelet-Derived Growth Factor/pharmacology
- Swine
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Affiliation(s)
- X Fang
- Department of Biochemistry, College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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34
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Harder DR, Roman RJ, Gebremedhin D, Birks EK, Lange AR. A common pathway for regulation of nutritive blood flow to the brain: arterial muscle membrane potential and cytochrome P450 metabolites. ACTA PHYSIOLOGICA SCANDINAVICA 1998; 164:527-32. [PMID: 9887975 DOI: 10.1111/j.1365-201x.1998.tb10702.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Perfusion pressure to the brain must remain relatively constant to provide rapid and efficient distribution of blood to metabolically active neurones. Both of these processes are regulated by the level of activation and tone of cerebral arterioles. The active state of cerebral arterial muscle is regulated, to a large extent, by the level of membrane potential. At physiological levels of arterial pressure, cerebral arterial muscle is maintained in an active state owing to membrane depolarization, compared with zero pressure load. As arterial pressure changes, so does membrane potential. The membrane is maintained in a relatively depolarized state because of, in part, inhibition of K+ channel activity. The activity of K+ channels, especially the large conductance Ca(2+)-activated K+ channel (KCa) is dependent upon the level of 20-HETE produced by arterial muscle. As arterial pressure increases, so does cytochrome P450 (P4504A) activity. P4504A enzymes catalyse omega-hydroxylation of arachidonic acid and formation of 20-hydroxyeicosatetraenoic acid (20-HETE). 20-HETE is a potent inhibitor of KCa which maintains membrane depolarization and muscle cell activation. Astrocytes also metabolize AA via P450 enzymes of the 2C11 gene family to produce epoxyeicosatrienoic acids (EETs). Epoxyeicosatrienoic acids are released from astrocytes by glutamate which 'spills over' during neuronal activity. These locally released EETs shunt blood to metabolically active neurones providing substrate to support neuronal function. This short paper will discuss the findings which support the above scenario, the purpose of which is to provide a basis for future studies on the molecular mechanisms through which cerebral blood flow matches metabolism.
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Affiliation(s)
- D R Harder
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee 53226, USA
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35
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Oltman CL, Weintraub NL, VanRollins M, Dellsperger KC. Epoxyeicosatrienoic acids and dihydroxyeicosatrienoic acids are potent vasodilators in the canine coronary microcirculation. Circ Res 1998; 83:932-9. [PMID: 9797342 DOI: 10.1161/01.res.83.9.932] [Citation(s) in RCA: 179] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cytochrome P450 epoxygenases convert arachidonic acid into 4 epoxyeicosatrienoic acid (EET) regioisomers, which were recently identified as endothelium-derived hyperpolarizing factors in coronary blood vessels. Both EETs and their dihydroxyeicosatrienoic acid (DHET) metabolites have been shown to relax conduit coronary arteries at micromolar concentrations, whereas the plasma concentrations of EETs are in the nanomolar range. However, the effects of EETs and DHETs on coronary resistance arterioles have not been examined. We administered EETs and DHETs to isolated canine coronary arterioles (diameter, 90.0+/-3.4 microm; distending pressure, 20 mm Hg) preconstricted by 30% to 60% of the resting diameter with endothelin. All 4 EET regioisomers produced potent, concentration-dependent vasodilation (EC50 values ranging from -12.7 to -10.1 log [M]) and were approximately 1000 times more potent than reported in conduit coronary arteries. The vasodilation produced by 14,15-EET was not attenuated by removal of the endothelium and indicated a direct action of 14,15-EET on microvascular smooth muscle. Likewise, 14,15-DHET, 11,12-DHET, 8,9-DHET, and the delta-lactone of 5,6-EET produced extremely potent vasodilation (EC50 values ranging from -15.8 to -13.1 log [M]). The vasodilation produced by these eicosanoids was highly potent in comparison to that produced by other vasodilators, including arachidonic acid (EC50=-7.5 log [M]). The epoxide hydrolase inhibitor, 4-phenylchalone oxide, which blocked the conversion of [3H]14,15-EET to [3H]14,15-DHET by canine coronary arteries, did not alter arteriolar dilation to 11,12-EET; thus, the potent vasodilation induced by EETs does not require formation of DHETs. In contrast, charybdotoxin (a KCa channel inhibitor) and KCl (a depolarizing agent) blocked vasodilation by 11,12-EET and 11,12-DHET. We conclude that EETs and DHETs potently dilate canine coronary arterioles via activation of KCa channels. The preferential ability of these compounds to dilate resistance blood vessels suggests that they may be important regulators of coronary circulation.
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Affiliation(s)
- C L Oltman
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA.
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36
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Zhao W, Parrish AR, Ramos KS. Constitutive and inducible expression of cytochrome P450IA1 and P450IB1 in human vascular endothelial and smooth muscle cells. In Vitro Cell Dev Biol Anim 1998; 34:671-3. [PMID: 9794216 DOI: 10.1007/s11626-998-0060-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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