Thrombin-activated human platelets acutely generate oxidized docosahexaenoic-acid-containing phospholipids via 12-lipoxygenase | Zendy

Lloyd T. Morgan | Zendy; Christopher P. Thomas | Zendy; Hartmut Kühn | Zendy; Valerie B. O’Donnell | Zendy

Open Access

Thrombin-activated human platelets acutely generate oxidized docosahexaenoic-acid-containing phospholipids via 12-lipoxygenase

Author(s) -

Lloyd T. Morgan,

Christopher P. Thomas,

Hartmut Kühn,

Valerie B. O’Donnell

Publication year - 2010

Publication title -

biochemical journal

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 1.706

H-Index - 265

eISSN - 1470-8728

pISSN - 0264-6021

DOI - 10.1042/bj20100415

Subject(s) - docosahexaenoic acid , chemistry , phospholipid , plasmalogen , thrombin , platelet , arachidonic acid , biochemistry , lipoxygenase , platelet activation , monoacylglycerol lipase , chromatography , recombinant dna , fatty acid , enzyme , polyunsaturated fatty acid , receptor , membrane , biology , endocannabinoid system , gene , immunology

Arachidonate-containing oxidized phospholipids are acutely generated by 12-LOX (12-lipoxygenase) in agonist-activated platelets. In the present study, formation of structurally related lipids by oxidation of DHA (docosahexaenoic acid)-containing phospholipids is demonstrated using lipidomic approaches. Precursor scanning reverse-phase LC (liquid chromatography)-MS/MS (tandem MS) identified a new family of lipids that comprise phospholipid-esterified HDOHE (hydroxydocosahexaenoic acid). Two diacyl and two plasmalogen PEs (phosphatidylethanolamines) containing predominantly the 14-HDOHE positional isomer (18:0p/14-HDOHE-PE, 18:0a/14-HDOHE-PE, 16:0a/14-HDOHE-PE and 16:0p/14-HDOHE-PE) were structurally characterized using MS/MS and by comparison with biogenic standards. An involvement of 12-LOX was indicated as purified recombinant human 12-LOX also generated the 14-HDOHE isomer from DHA. Pharmacological studies using inhibitors and recombinant platelet 12-LOX indicate that they form via esterification of newly formed non-esterified HDOHE. HDOHE-PEs formed at significant rates (2-4 ng/4×10(7) cells) within 2-180 min of thrombin stimulation, and their formation was blocked by calcium chelation. In summary, a new family of oxidized phospholipid was identified in thrombin-activated human platelets.

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