| COX-2-dependent and -independent biosynthesis of dihydroxy-arachidonic acids in activated human leukocytes. | |
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MedLine Citation:
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PMID: 22068350 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Biosynthesis of 5,15-dihydroxyeicosatetraenoic acid (5,15-diHETE) in leukocytes involves consecutive oxygenation of arachidonic acid by 5-LOX and 15-LOX in either order. Here, we analyzed the contribution of COX-2 to the biosynthesis of 5,15-diHETE and 5,11-diHETE in isolated human leukocytes activated with LPS and calcium ionophore A23187. Transformation of arachidonic acid was initiated by 5-LOX providing 5S-HETE as a substrate for COX-2 forming 5S,15S-diHETE, 5S,15R-diHETE, and 5S,11R-diHETE as shown by LC-MS and chiral phase HPLC analyses. The levels of 5,15-diHETE were 0.45 +/- 0.2 ng/106 cells (mean +/- SEM, n=6), reaching about half the level of LTB4 (1.3 +/- 0.5 ng/106 cells, n=6). The COX-2 specific inhibitor NS-398 reduced the levels of 5,15-diHETE to below 0.02 ng/106 cells in four out of six samples. Similar reduction was achieved by MK-886, an inhibitor of 5-LOX activating protein. Aspirin-treatment of the activated cells allowed formation of 5,15-diHETE (0.1 +/- 0.05 ng/106 cells, n=6) but, as expected, abolished formation of 5,11-diHETE. The mixture of activated cells also produced 5S,12S-diHETE with the unusual 6E,8Z,10E double bond configuration, implicating biosynthesis by 5-LOX and 12-LOX activity rather than by hydrolysis of the leukotriene A4-epoxide. Exogenous octadeuterated 5S-HETE and 15S-HETE were converted to 5,15-diHETE, implicating that multiple oxygenation pathways of arachidonic acid occur in activated leukocytes. The contribution of COX-2 to the biosynthesis of dihydroxylated derivatives of arachidonic acid provides evidence for functional coupling with 5-LOX in activated human leukocytes. |
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Authors:
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Noemi Tejera; William E Boeglin; Takashi Suzuki; Claus Schneider |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-11-7 |
Journal Detail:
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Title: Journal of lipid research Volume: - ISSN: 0022-2275 ISO Abbreviation: - Publication Date: 2011 Nov |
Date Detail:
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Created Date: 2011-11-9 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0376606 Medline TA: J Lipid Res Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Vanderbilt University, United States; |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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