1
|
Leow JWH, Chan ECY. CYP2J2-mediated metabolism of arachidonic acid in heart: A review of its kinetics, inhibition and role in heart rhythm control. Pharmacol Ther 2024; 258:108637. [PMID: 38521247 DOI: 10.1016/j.pharmthera.2024.108637] [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: 06/18/2023] [Revised: 02/06/2024] [Accepted: 03/11/2024] [Indexed: 03/25/2024]
Abstract
Cytochrome P450 2 J2 (CYP2J2) is primarily expressed extrahepatically and is the predominant epoxygenase in human cardiac tissues. This highlights its key role in the metabolism of endogenous substrates. Significant scientific interest lies in cardiac CYP2J2 metabolism of arachidonic acid (AA), an omega-6 polyunsaturated fatty acid, to regioisomeric bioactive epoxyeicosatrienoic acid (EET) metabolites that show cardioprotective effects including regulation of cardiac electrophysiology. From an in vitro perspective, the accurate characterization of the kinetics of CYP2J2 metabolism of AA including its inhibition and inactivation by drugs could be useful in facilitating in vitro-in vivo extrapolations to predict drug-AA interactions in drug discovery and development. In this review, background information on the structure, regulation and expression of CYP2J2 in human heart is presented alongside AA and EETs as its endogenous substrate and metabolites. The in vitro and in vivo implications of the kinetics of this endogenous metabolic pathway as well as its perturbation via inhibition and inactivation by drugs are elaborated. Additionally, the role of CYP2J2-mediated metabolism of AA to EETs in cardiac electrophysiology will be expounded.
Collapse
Affiliation(s)
- Jacqueline Wen Hui Leow
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
| |
Collapse
|
2
|
Lipid mediators generated by the cytochrome P450—Epoxide hydrolase pathway. ADVANCES IN PHARMACOLOGY 2023; 97:327-373. [DOI: 10.1016/bs.apha.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
3
|
Frömel T, Naeem Z, Pirzeh L, Fleming I. Cytochrome P450-derived fatty acid epoxides and diols in angiogenesis and stem cell biology. Pharmacol Ther 2021; 234:108049. [PMID: 34848204 DOI: 10.1016/j.pharmthera.2021.108049] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/04/2021] [Accepted: 11/24/2021] [Indexed: 10/19/2022]
Abstract
Cytochrome P450 (CYP) enzymes are frequently referred to as the third pathway for the metabolism of arachidonic acid. While it is true that these enzymes generate arachidonic acid epoxides i.e. the epoxyeicosatrienoic acids (EETs), they are able to accept a wealth of ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) to generate a large range of regio- and stereo-isomers with distinct biochemical properties and physiological actions. Probably the best studied are the EETs which have well documented effects on vascular reactivity and angiogenesis. CYP enzymes can also participate in crosstalk with other PUFA pathways and metabolize prostaglandin G2 and H2, which are the precursors of effector prostaglandins, to affect macrophage function and lymphangiogenesis. The activity of the PUFA epoxides is thought to be kept in check by the activity of epoxide hydrolases. However, rather than being inactive, the diols generated have been shown to regulate neutrophil activation, stem and progenitor cell proliferation and Notch signaling in addition to acting as exercise-induced lipokines. Excessive production of PUFA diols has also been implicated in pathologies such as severe respiratory distress syndromes, including COVID-19, and diabetic retinopathy. This review highlights some of the recent findings related to this pathway that affect angiogenesis and stem cell biology.
Collapse
Affiliation(s)
- Timo Frömel
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt am Main, Germany
| | - Zumer Naeem
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt am Main, Germany
| | - Lale Pirzeh
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt am Main, Germany
| | - Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt am Main, Germany; German Centre for Cardiovascular Research (DZHK) Partner Site Rhein-Main, Frankfurt am Main, Germany; The Cardio-Pulmonary Institute, Frankfurt am Main, Germany.
| |
Collapse
|
4
|
Otoki Y, Metherel AH, Pedersen T, Yang J, Hammock BD, Bazinet RP, Newman JW, Taha AY. Acute Hypercapnia/Ischemia Alters the Esterification of Arachidonic Acid and Docosahexaenoic Acid Epoxide Metabolites in Rat Brain Neutral Lipids. Lipids 2020; 55:7-22. [PMID: 31691988 PMCID: PMC7220815 DOI: 10.1002/lipd.12197] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 12/15/2022]
Abstract
In the brain, approximately 90% of oxylipins are esterified to lipids. However, the significance of this esterification process is not known. In the present study, we (1) validated an aminopropyl solid phase extraction (SPE) method for separating esterified lipids using 100 and 500 mg columns and (2) applied the method to quantify the distribution of esterified oxylipins within phospholipids (PL) and neutral lipids (NL) (i.e. triacylglycerol and cholesteryl ester) in rats subjected to head-focused microwave fixation (controls) or CO2 -induced hypercapnia/ischemia. We hypothesized that oxylipin esterification into these lipid pools will be altered following CO2 -induced hypercapnia/ischemia. Lipids were extracted from control (n = 8) and CO2 -asphyxiated (n = 8) rat brains and separated on aminopropyl cartridges to yield PL and NL. The separated lipid fractions were hydrolyzed, purified with hydrophobic-lipophilic-balanced SPE columns, and analyzed with ultra-high-pressure liquid chromatography coupled to tandem mass spectrometry. Method validation showed that the 500 mg (vs 100 mg) aminopropyl columns yielded acceptable separation and recovery of esterified fatty acid epoxides but not other oxylipins. Two epoxides of arachidonic acid (ARA) were significantly increased, and three epoxides of docosahexaenoic acid (DHA) were significantly decreased in brain NL of CO2 -asphyxiated rats compared to controls subjected to head-focused microwave fixation. PL-bound fatty acid epoxides were highly variable and did not differ significantly between the groups. This study demonstrates that hypercapnia/ischemia alters the concentration of ARA and DHA epoxides within NL, reflecting an active turnover process regulating brain fatty acid epoxide concentrations.
Collapse
Affiliation(s)
- Yurika Otoki
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, One Shields Avenue, Davis, CA 95616, USA
- Food and Biodynamic Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan
| | - Adam H. Metherel
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, ON, M5S 1A8, Canada
| | - Theresa Pedersen
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Jun Yang
- Department of Entomology and Nematology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA
- Comprehensive Cancer Center, Medical Center, University of California, Davis, CA 95616, USA
| | - Bruce D. Hammock
- Department of Entomology and Nematology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA
- Comprehensive Cancer Center, Medical Center, University of California, Davis, CA 95616, USA
- West Coast Metabolomics Center, Genome Center, University of California–Davis, Davis, CA 95616, USA
| | - Richard P. Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, ON, M5S 1A8, Canada
| | - 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
- United States Department of Agriculture, Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA 95616, USA
| | - Ameer Y. Taha
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, One Shields Avenue, Davis, CA 95616, USA
- West Coast Metabolomics Center, Genome Center, University of California–Davis, Davis, CA 95616, USA
| |
Collapse
|
5
|
Dos Santos LRB, Fleming I. Role of cytochrome P450-derived, polyunsaturated fatty acid mediators in diabetes and the metabolic syndrome. Prostaglandins Other Lipid Mediat 2019; 148:106407. [PMID: 31899373 DOI: 10.1016/j.prostaglandins.2019.106407] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 11/14/2019] [Accepted: 12/23/2019] [Indexed: 12/17/2022]
Abstract
Over the last decade, cases of metabolic syndrome and type II diabetes have increased exponentially. Exercise and ω-3 polyunsaturated fatty acid (PUFA)-enriched diets are usually prescribed but no therapy is effectively able to restore the impaired glucose metabolism, hypertension, and atherogenic dyslipidemia encountered by diabetic patients. PUFAs are metabolized by different enzymes into bioactive metabolites with anti- or pro-inflammatory activity. One important class of PUFA metabolizing enzymes are the cytochrome P450 (CYP) enzymes that can generate a series of bioactive products, many of which have been attributed protective/anti-inflammatory and insulin-sensitizing effects in animal models. PUFA epoxides are, however, further metabolized by the soluble epoxide hydrolase (sEH) to fatty acid diols. The biological actions of the latter are less well understood but while low concentrations may be biologically important, higher concentrations of diols derived from linoleic acid and docosahexaenoic acid have been linked with inflammation. One potential application for sEH inhibitors is in the treatment of diabetic retinopathy where sEH expression and activity is elevated as are levels of a diol of docosahexaenoic acid that can induce the destabilization of the retina vasculature.
Collapse
Affiliation(s)
- Laila R B Dos Santos
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt, Germany; German Centre for Cardiovascular Research (DZHK) Partner Site Rhein-Main, Germany
| | - Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt, Germany; German Centre for Cardiovascular Research (DZHK) Partner Site Rhein-Main, Germany.
| |
Collapse
|
6
|
Fleming I. New Lipid Mediators in Retinal Angiogenesis and Retinopathy. Front Pharmacol 2019; 10:739. [PMID: 31333461 PMCID: PMC6624440 DOI: 10.3389/fphar.2019.00739] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 06/07/2019] [Indexed: 12/31/2022] Open
Abstract
Retinal diseases associated with vascular destabilization and the inappropriate proliferation of retinal endothelial cells have major consequences on the retinal vascular network. In extreme cases, the development of hypoxia, the upregulation of growth factors, and the hyper-proliferation of unstable capillaries can result in bleeding and vision loss. While anti-vascular endothelial growth factor therapy and laser retinal photocoagulation can be used to treat the symptoms of late stage disease, there is currently no treatment available that can prevent disease progression. Cytochrome P450 enzymes metabolize endogenous substrates (polyunsaturated fatty acids) to bioactive fatty acid epoxides that demonstrate biological activity with generally protective/anti-inflammatory and insulin-sensitizing effects. These epoxides are further metabolized by the soluble epoxide hydrolase (sEH) to fatty acid diols, high concentrations of which have vascular destabilizing effects. Recent studies have identified increased sEH expression and activity and the subsequent generation of the docosahexaenoic acid-derived diol; 19,20-dihydroxydocosapentaenoic acid, as playing a major role in the development of diabetic retinopathy. This review summarizes current understanding of the roles of cytochrome P450 enzyme and sEH–derived PUFA mediators in retinal disease.
Collapse
Affiliation(s)
- Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe-University, Frankfurt, Germany.,German Centre for Cardiovascular Research (DZHK) partner site RheinMain, Frankfurt, Germany
| |
Collapse
|
7
|
A sensitive LC-MS/MS method for the quantification of regioisomers of epoxyeicosatrienoic and dihydroxyeicosatrienoic acids in human plasma during endothelial stimulation. Anal Bioanal Chem 2016; 409:1845-1855. [PMID: 27981341 DOI: 10.1007/s00216-016-0129-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/16/2016] [Accepted: 11/30/2016] [Indexed: 10/20/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are vasodilating lipid mediators metabolized into dihydroxyeicosatrienoic acids (DHETs) by soluble epoxide hydrolase. We aimed to develop a LC-MS/MS method to quantify EETs and DHETs in human plasma and monitored their levels during vascular endothelial stimulation. Plasma samples, collected from 14 healthy and five hypertensive subjects at baseline and during radial artery endothelium-dependent flow-mediated dilatation, were spiked with internal standards. Lipids were then extracted by a modified Bligh and Dyer method and saponified to release bound EETs and DHETs. Samples were purified by a second liquid-liquid extraction and analyzed by LC-MS/MS. The assay allowed identification of (±)8(9)-epoxy-5Z,11Z,14Z-eicosatrienoic acid (8,9-EET); (±)11(12)-epoxy-5Z,8Z,14Z-eicosatrienoic acid (11,12-EET); (±)14(15)-epoxy-5Z,8Z,11Z-eicosatrienoic acid (14,15-EET); (±)8,9-dihydroxy-5Z,11Z,14Z-eicosatrienoic acid (8,9-DHET); (±)11,12-dihydroxy-5Z,8Z,14Z-eicosatrienoic acid (11,12-DHET); and (±)14,15-dihydroxy-5Z,8Z,11Z-eicosatrienoic acid (14,15-DHET). (±)5(6)-epoxy-5Z,11Z,14Z-eicosatrienoic acid (5,6-EET) was virtually undetectable due to its chemical instability. The limits of quantification were 0.25 ng/mL for DHETs and 0.5 ng/mL for EETs. Intra- and inter-assay variations ranged from 1.6 to 13.2%. Heating induced a similar increase in 8,9-EET, 11,12-EET, and 14,15-EET levels and in corresponding DHET levels in healthy but not in hypertensive subjects. We validated a sensitive LC-MS/MS method for measuring simultaneously plasma EET and DHET regioisomers in human plasma and showed its interest for assessing endothelial function.
Collapse
|
8
|
Fleming I. The factor in EDHF: Cytochrome P450 derived lipid mediators and vascular signaling. Vascul Pharmacol 2016; 86:31-40. [DOI: 10.1016/j.vph.2016.03.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/20/2016] [Accepted: 03/06/2016] [Indexed: 12/31/2022]
|
9
|
Fleming I. The Pharmacology of the Cytochrome P450 Epoxygenase/Soluble Epoxide Hydrolase Axis in the Vasculature and Cardiovascular Disease. Pharmacol Rev 2014; 66:1106-40. [DOI: 10.1124/pr.113.007781] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
|
10
|
Falck JR, Koduru SR, Mohapatra S, Manne R, Atcha KR, Atcha R, Manthati VL, Capdevila JH, Christian S, Imig JD, Campbell WB. 14,15-Epoxyeicosa-5,8,11-trienoic Acid (14,15-EET) surrogates: carboxylate modifications. J Med Chem 2014; 57:6965-72. [PMID: 25119815 PMCID: PMC4148164 DOI: 10.1021/jm500262m] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
The cytochrome P450 eicosanoid 14,15-epoxyeicosa-5,8,11-trienoic
acid (14,15-EET) is a powerful endogenous autacoid that has been ascribed
an impressive array of physiologic functions including regulation
of blood pressure. Because 14,15-EET is chemically and metabolically
labile, structurally related surrogates containing epoxide bioisosteres
were introduced and have become useful in vitro pharmacologic tools
but are not suitable for in vivo applications. A new generation of
EET mimics incorporating modifications to the carboxylate were prepared
and evaluated for vasorelaxation and inhibition of soluble epoxide
hydrolase (sEH). Tetrazole 19 (ED50 0.18 μM)
and oxadiazole-5-thione 25 (ED50 0.36 μM)
were 12- and 6-fold more potent, respectively, than 14,15-EET as vasorelaxants;
on the other hand, their ability to block sEH differed substantially,
i.e., 11 vs >500 nM. These data will expedite the development of
potent
and specific in vivo drug candidates.
Collapse
Affiliation(s)
- John R Falck
- Departments of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center , 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
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.
Collapse
Affiliation(s)
- William G Sanders
- Department of Pharmaceutics, University of Utah, Salt Lake City, Utah 84112, USA
| | | | | | | | | |
Collapse
|
12
|
Fife KL, Liu Y, Schmelzer KR, Tsai HJ, Kim IH, Morisseau C, Hammock BD, Kroetz DL. Inhibition of soluble epoxide hydrolase does not protect against endotoxin-mediated hepatic inflammation. J Pharmacol Exp Ther 2008; 327:707-15. [PMID: 18815352 DOI: 10.1124/jpet.108.142398] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Epoxyeicosatrienoic acids (EETs) are derived from cytochrome P450-catalyzed epoxygenation of arachidonic acid and have emerged as important mediators of numerous biological effects. The major elimination pathway for EETs is through soluble epoxide hydrolase (sEH)-catalyzed metabolism to dihydroxyeicosatrienoic acids (DHETs). Based on previous studies showing that EETs have anti-inflammatory effects, we hypothesized that chronic inhibition of sEH would attenuate a lipopolysaccharide (LPS)-induced inflammatory response in vivo. Continuous dosing of the sEH inhibitors 12-(3-adamantan-1-ylureido)-dodecanoic acid (AUDA), a polyethylene glycol ester of AUDA, and 1-adamantan-1-yl-3-(5-(2-(2-ethoxyethoxy)ethoxy)-pentyl)urea resulted in robust exposure to the inhibitor and target engagement, as evidenced by significant increases in plasma EET/DHET ratios following 6 days of inhibitor treatment. However, sEH inhibitor treatment was not associated with an attenuation of LPS-induced inflammatory gene expression in the liver, and AUDA did not protect from LPS-induced neutrophil infiltration. Furthermore, Ephx2-/-mice that lack sEH expression and have significantly increased plasma EET/DHET ratios were not protected from LPS-induced inflammatory gene expression or neutrophil accumulation in the liver. LPS did have an effect on sEH expression and function, as evident from a significant down-regulation of Ephx2 mRNA and a significant shift in plasma EET/DHET ratios 4 h after LPS treatment. In conclusion, there was no evidence that increasing EET levels in vivo could modulate an LPS-induced inflammatory response in the liver. However, LPS did have significant effects on plasma eicosanoid levels and hepatic Ephx2 expression, suggesting that in vivo EET levels are modulated in response to an inflammatory signal.
Collapse
Affiliation(s)
- Kimberly L Fife
- Department of Biopharmaceutical Sciences, University of California, San Francisco, California, USA
| | | | | | | | | | | | | | | |
Collapse
|
13
|
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.
Collapse
Affiliation(s)
- Arthur A Spector
- Dept. of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
| | | |
Collapse
|
14
|
Michaelis UR, Fleming I. From endothelium-derived hyperpolarizing factor (EDHF) to angiogenesis: Epoxyeicosatrienoic acids (EETs) and cell signaling. Pharmacol Ther 2005; 111:584-95. [PMID: 16380164 DOI: 10.1016/j.pharmthera.2005.11.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Accepted: 11/23/2005] [Indexed: 12/01/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are generated from arachidonic acid by cytochrome P450 (CYP) epoxygenases. The expression of CYP epoxygenases in endothelial cells is determined by a number of physical (fluid shear stress and cyclic stretch) and pharmacological stimuli as well as by hypoxia. The activation of CYP epoxygenases in endothelial cells is an important step in the nitric oxide and prostacyclin (PGI2)-independent vasodilatation of several vascular beds and EETs have been identified as endothelium-derived hyperpolarizing factors (EDHFs). However, in addition to regulating vascular tone, EETs modulate several signaling cascades and affect cell proliferation, cell migration, and angiogenesis. Signaling molecules modulated by EETs include tyrosine kinases and phosphatases, mitogen-activated protein kinases, protein kinase A (PKA), cyclooxygenase (COX)-2, and several transcription factors. This review summarizes the role of CYP-derived EETs in cell signaling and focuses particularly on their role as intracellular amplifiers of endothelial cell hyperpolarization as well as in cell proliferation and angiogenesis. The angiogenic properties of CYP epoxygenases and CYP-derived EETs implicate that these enzymes may well be accessible targets for anti-angiogenic as well as angiogenic therapies.
Collapse
Affiliation(s)
- U Ruth Michaelis
- Vascular Signalling Group, Institut für Kardiovaskuläre Physiologie, Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | | |
Collapse
|
15
|
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.
Collapse
Affiliation(s)
- Xiang Fang
- Dept. of Biochemistry, Univ. of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Chen P, Hu S, Harmon SD, Moore SA, Spector AA, Fang X. Metabolism of anandamide in cerebral microvascular endothelial cells. Prostaglandins Other Lipid Mediat 2005; 73:59-72. [PMID: 15165032 DOI: 10.1016/j.prostaglandins.2003.11.005] [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] [Indexed: 10/26/2022]
Abstract
Anandamide (N-arachidonoylethanolamine, AEA), an endogenous cannabinoid receptor agonist, causes potent vasodilation in the cerebral circulation through an endothelial-dependent or -independent mechanism. We have investigated the processing of [3H]AEA in cultured mouse cerebral microvascular endothelial cells (MEC) in order to better understand its mechanism of action in the cerebral vasculature. These cells took up anandamide very quickly, reaching a maximum value in 5 min and remaining at that level for at least 8 h. Analysis of the cell lipids demonstrated that, in addition to free anandamide, radioactivity was incorporated into phosphatidylcholine (PC), phosphatidylinositol (PI), and phosphatidylethanolamine (PE) in a time-dependent manner. Analysis of the hydrolyzed cell lipids indicated that anandamide was converted to arachidonic acid, a process that was inhibited by the selective fatty acid amide hydrolase inhibitor oleyl trifluoromethyl ketone (OTMK). Phospholipase A2 (PLA2) hydrolysis of the PC, PI, and PE fractions indicated that the arachidonic acid formed from anandamide was esterified predominately into sn-2 position of the endothelial phospholipids. Furthermore, anandamide and arachidonic acid were released when the cells were incubated with A23187. These results suggest that the biological activity of anandamide might be regulated by its rapid uptake and calcium-dependent release in endothelial cells, and conversion of anandamide to arachidonic acid might serve as an inactivation process in the cerebral microcirculation.
Collapse
Affiliation(s)
- Ping Chen
- Department of Biochemistry, University of Iowa College of Medicine, 4-403 BSB, Iowa City, IA 52242, USA
| | | | | | | | | | | |
Collapse
|
17
|
Kaduce TL, Fang X, Harmon SD, Oltman CL, Dellsperger KC, Teesch LM, Gopal VR, Falck JR, Campbell WB, Weintraub NL, Spector AA. 20-Hydroxyeicosatetraenoic Acid (20-HETE) Metabolism in Coronary Endothelial Cells. J Biol Chem 2004; 279:2648-56. [PMID: 14612451 DOI: 10.1074/jbc.m306849200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have investigated the role of endothelial cells in the metabolism of 20-hydroxyeicosatetraenoic acid (20-HETE), a vasoactive mediator synthesized from arachidonic acid by cytochrome P450 omega-oxidases. Porcine coronary artery endothelial cells (PCEC) incorporated 20-[(3)H]HETE primarily into the sn-2 position of phospholipids through a coenzyme A-dependent process. The incorporation was reduced by equimolar amounts of arachidonic, eicosapentaenoic or 8,9-epoxyeicosatrienoic acids, but some uptake persisted even when a 10-fold excess of arachidonic acid was available. The retention of 20-[(3)H]HETE increased substantially when methyl arachidonoyl fluorophosphonate, but not bromoenol lactone, was added, suggesting that a Ca(2+)-dependent cytosolic phospholipase A(2) released the 20-HETE contained in PCEC phospholipids. Addition of calcium ionophore A23187 produced a rapid release of 20-[(3)H]HETE from the PCEC, a finding that also is consistent with a Ca(2+)-dependent mobilization process. PCEC also converted 20-[(3)H]HETE to 20-carboxy-arachidonic acid (20-COOH-AA) and 18-, 16-, and 14-carbon beta-oxidation products. 20-COOH-AA produced vasodilation in porcine coronary arterioles, but 20-HETE was inactive. These results suggest that the incorporation of 20-HETE and its subsequent conversion to 20-COOH-AA in the endothelium may be important in modulating coronary vascular function.
Collapse
Affiliation(s)
- Terry L Kaduce
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|