title: Platelet 12-lipoxygenase activation via glycoprotein VI: involvement of multiple signaling pathways in agonist control of H(P)ETE synthesis.
abstract: Lipoxygenases (LOX) contribute to vascular disease and inflammation through generation of bioactive lipids, including 12-hydro(pero)xyeicosatetraenoic acid (12-H(P)ETE). The physiological mechanisms that acutely control LOX product generation in mammalian cells are uncharacterized. Human platelets that contain a 12-LOX isoform (p12-LOX) were used to define pathways that activate H(P)ETE synthesis in the vasculature. Collagen and collagen-related peptide (CRP) (1 to 10 microg/mL) acutely induced platelet 12-H(P)ETE synthesis. This implicated the collagen receptor glycoprotein VI (GPVI), which signals via the immunoreceptor-based activatory motif (ITAM)-containing FcRgamma chain. Conversely, thrombin only activated at high concentrations (> 0.2 U/mL), whereas U46619 and ADP alone were ineffective. Collagen or CRP-stimulated 12-H(P)ETE generation was inhibited by staurosporine, PP2, wortmannin, BAPTA/AM, EGTA, and L-655238, implicating src-tyrosine kinases, PI3-kinase, Ca2+ mobilization, and p12-LOX translocation. In contrast, protein kinase C (PKC) inhibition potentiated 12-H(P)ETE generation. Finally, activation of the immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing platelet endothelial cell adhesion molecule (PECAM-1) inhibited p12-LOX product generation. This study characterizes a receptor-dependent pathway for 12-H(P)ETE synthesis via the collagen receptor GPVI, which is negatively regulated by PECAM-1 and PKC, and demonstrates a novel link between immune receptor signaling and lipid mediator generation in the vasculature.
authors.affiliation: Department of Medical Biochemistry and Immunology, University of Wales College of Medicine, Heath Park, Cardiff, UK. coffeymj@cardiff.ac.uk
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Coffey
authors.forename: Gavin E
authors.initials: GE
authors.lastname: Jarvis
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Gibbins
authors.forename: Barbara
authors.initials: B
authors.lastname: Coles
authors.forename: Natasha E
authors.initials: NE
authors.lastname: Barrett
authors.forename: Oliver R E
authors.initials: OR
authors.lastname: Wylie
authors.forename: Valerie B
authors.initials: VB
authors.lastname: O'Donnell
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000096:biosynthesis / Q000097:blood; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000494:pharmacology; D020816:Amino Acid Motifs; D001092:Arachidonate 12-Lipoxygenase / Q000097:blood* / Q000378:metabolism; D016718:Arachidonic Acid / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology*; D000001:Calcimycin / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002352:Carrier Proteins / Q000494:pharmacology; D003094:Collagen / Q000494:pharmacology; D051545:Cyclooxygenase 1; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007249:Inflammation / Q000276:immunology; D007527:Isoenzymes / Q000502:physiology; D015289:Leukotrienes / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism; D008565:Membrane Proteins; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D015539:Platelet Activation / Q000187:drug effects; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000502:physiology; D010980:Platelet Membrane Glycoproteins / Q000502:physiology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000502:physiology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D011804:Quinolines / Q000494:pharmacology; D017452:Receptors, IgG / Q000502:physiology; D013917:Thrombin / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology
chemical_list: D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D007527:Isoenzymes; C095607:L 655238; D015289:Leukotrienes; D008565:Membrane Proteins; D010455:Peptides; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D010980:Platelet Membrane Glycoproteins; D011804:Quinolines; D017452:Receptors, IgG; C435908:collagen-related peptide; C098341:platelet membrane glycoprotein VI; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D016718:Arachidonic Acid; D000001:Calcimycin; D004533:Egtazic Acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000244:Adenosine Diphosphate; C021201:12-HPETE; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D003094:Collagen; D001092:Arachidonate 12-Lipoxygenase; D051545:Cyclooxygenase 1; C496511:PTGS1 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D011493:Protein Kinase C; D048051:p38 Mitogen-Activated Protein Kinases; D013917:Thrombin