Document Detail

COX-2-dependent and -independent biosynthesis of dihydroxy-arachidonic acids in activated human leukocytes.
MedLine Citation:
PMID:  22068350     Owner:  NLM     Status:  MEDLINE    
Biosynthesis of 5,15-dihydroxyeicosatetraenoic acid (5,15-diHETE) in leukocytes involves consecutive oxygenation of arachidonic acid by 5-lipoxygenase (LOX) and 15-LOX in either order. Here, we analyzed the contribution of cyclooxygenase (COX)-2 to the biosynthesis of 5,15-diHETE and 5,11-diHETE in isolated human leukocytes activated with lipopolysaccharide 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 of six samples. Similar reduction was achieved by MK-886, an inhibitor of 5-LOX activating protein but the above differences were not statistically significant. 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.
Noemi Tejera; William E Boeglin; Takashi Suzuki; Claus Schneider
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-11-07
Journal Detail:
Title:  Journal of lipid research     Volume:  53     ISSN:  0022-2275     ISO Abbreviation:  J. Lipid Res.     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2011-12-16     Completed Date:  2012-04-09     Revised Date:  2013-06-27    
Medline Journal Info:
Nlm Unique ID:  0376606     Medline TA:  J Lipid Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  87-94     Citation Subset:  IM    
Division of Clinical Pharmacology, Department of Pharmacology and Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical School, Nashville, TN, USA.
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MeSH Terms
Arachidonate 15-Lipoxygenase / metabolism
Arachidonate 5-Lipoxygenase / metabolism
Cyclooxygenase 2 / metabolism*
Hydroxyeicosatetraenoic Acids / biosynthesis*,  metabolism
Leukocytes / metabolism*
Grant Support
Reg. No./Substance:
0/Hydroxyeicosatetraenoic Acids; 82200-87-1/5,15-dihydroxy-6,8,11,13-eicosatetraenoic acid; EC 15-Lipoxygenase; EC 5-Lipoxygenase; EC 2

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