Abstract
The 5-lipoxygenase product 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE) is a potent chemoattractant for neutrophils and eosinophils, and its actions are mediated by the oxoeicosanoid (OXE) receptor, a member of the G protein-coupled receptor family. To define the requirements for activation of the OXE receptor, we have synthesized a series of 5-oxo-6E,8Z-dienoic acids with chain lengths between 12 and 20 carbons, as well as a series of 20-carbon 5-oxo fatty acids, either fully saturated or containing between one and five double bonds. The effects of these compounds on neutrophils (calcium mobilization, CD11b expression, and cell migration) and eosinophils (actin polymerization) were compared with those of 5-oxo-ETE. The C12 and C14 analogs were without appreciable activity, whereas the C16 5-oxo-dienoic acid was a weak partial agonist. In contrast, the corresponding C18 analog (5-oxo-18:2) was nearly as potent as 5-oxo-ETE. Among the C20 analogs, the fully saturated compound had virtually no activity, whereas 5-oxo-6E-eicosenoic acid had only weak agonist activity. In contrast, 5-oxo-6E,8Z,11Z-eicosatrienoic acid (5-oxo-20:3) and its 8-trans isomer were approximately equipotent with 5-oxo-ETE in activating granulocytes. Because of the potent effects of 5-oxo-20:3, we investigated its formation from Mead acid (5Z,8Z,11Z-eicosatrienoic acid), which accumulates in dietary essential fatty acid deficiency, by neutrophils. The main Mead acid metabolite identified was 5-hydroxy-6,8,11-eicosatrienoic acid, followed by 5-oxo-20:3 and two 6-trans isomers of leukotriene B3. We conclude that optimal activation of the OXE receptor is achieved with 5-oxo-ETE, 5-oxo-18:2, and 5-oxo-20:3, and that the latter compound could potentially be formed under conditions of essential fatty acid deficiency.
Footnotes
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This work was supported by the Canadian Institutes of Health Research (Grant MOP-6254; to W.S.P.), the Quebec Heart and Stroke Foundation, the JT Costello Memorial Research Fund, and the National Institutes of Health (Grant HL81873; to J.R.). J.R. received support from the National Science Foundation for the AMX-360 (Grant CHE-90-13145) and Bruker 400 MHz (Grant CHE-03-42251) nuclear magnetic resonance instruments.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.107.134908.
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ABBREVIATIONS: 5-LO, 5-lipoxygenase; LT, leukotriene; 5-HETE, 5S-hydroxy-6E,8Z,11Z,14Z-eicosatetraenoic acid; 5-oxo-ETE, 5-oxo-6E,8Z, 11Z,14Z-eicosatetraenoic acid; 5-HEDH, 5-hydroxyeicosanoid dehydrogenase; MK886, 3-[1-(p-chlorophenyl)-5-isopropyl-3-tert-butylthio-1H-indol-2-yl]-2,2-dimethylpropanoic acid; OXE, oxoeicosanoid; 5-oxo-20:5 (5-oxo-EPE), 5-oxo-6E,8Z,11Z,14Z,17Z-eicosapentaenoic acid; 5-HEPE, 5S-hydroxy-6E,8Z,11Z,14Z,17Z-eicosapentaenoic acid; 5-hydroxy-20:3, 5-hydroxy-6E,8Z,11Z-eicosatrienoic acid; RP-HPLC, reversed-phase high-performance liquid chromatography; 13-HODE, 13S-hydroxy-9Z,11E-octadecadienoic acid; PMA, phorbol 12-myristate 13-acetate; A23187, calcimycin; PBS, phosphate-buffered saline; NBD-phallacidin, N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)phallacidin; 5-oxo-14:2, 5-oxo-6E, 8Z-tetradecadienoic acid; 5-oxo-16:2, 5-oxo-6E,8Z-hexadecadienoic acid; 5-oxo-20:3, 5-oxo-6E,8Z,11Z-eicosatrienoic acid; 5-oxo-20:4 (5-oxo-ETE), 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid; 5-oxo-18:1, 5-oxo-6E-octadecenoic acid; 5-oxo-18:2, 5-oxo-6E,8Z-octadecadienoic acid; 5-oxo-20:2, 5-oxo-6E,8Z-eicosadienoic acid; 5-oxo-12:2, 5-oxo-6E,8Z-dodecadienoic acid; 5-oxoeicosanoic acid; 5-oxo-20:1, 5-oxo-6E-eicosenoic acid; 5-oxo-20:0, 5-oxoeicosanoic acid; 5-oxo-Δ6,8,14-20:3, 5-oxo-6E,8Z,14Z-eicosatrienoic acid; tR, retention time; FTMS, Fourier transform mass spectrometry; PAF, platelet-activating factor; PUFA, polyunsaturated fatty acid; 8-trans-5-oxo-20:3, 8-trans-5-oxo-6E,8E,11Z-eicosatrienoic acid; MS, mass spectrometry.
- Received December 5, 2007.
- Accepted February 20, 2008.
- The American Society for Pharmacology and Experimental Therapeutics
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