title: Stimulation of platelet-activating factor synthesis in human endothelial cells by activation of the de novo pathway. Phorbol 12-myristate 13-acetate activates 1-alkyl-2-lyso-sn-glycero-3-phosphate:acetyl-CoA acetyltransferase and dithiothreitol-insensitive 1-alkyl-2-acetyl-sn-glycerol:CDP-choline cholinephosphotransferase.
abstract: Human umbilical vein endothelial cells (HUVEC) produce platelet-activating factor (PAF) by a remodeling pathway involving a phospholipase A2 followed by an acetyl-CoA-dependent acetyltransferase which acetylates a lyso-PAF intermediate to form PAF and is stimulated by a variety of agents that generate inflammatory and allergic responses. A second route for PAF synthesis in mammalian tissues is a de novo pathway, which requires the participation of three enzymes: 1-alkyl-2-lyso-sn-glycero-3-phosphate (alkyllyso-GP): acetyl-CoA acetyltransferase, 1-alkyl-2-acetyl-sn-glycero-3-phosphate phosphohydrolase, and dithiothreitol (DDT)-insensitive 1-alkyl-2-acetyl-sn-glycerol (alkylacetyl-G):CDP-cholinecholinephosphotransferase. In the present study we show that protein kinase C activation by phorbol 12-myristate 13-acetate (PMA) induces PAF production in HUVEC by an increase of both alkyllyso-GP:acetyl-CoA acetyltransferase and DTT-insensitive alkylacetyl-G:CDP-choline choline-phosphotransferase. PAF synthesis, labeled precursors [( 3H]acetate and [methyl-3H]choline) incorporation, and both enzyme activities of the de novo pathway increase concomitantly in response to different doses of PMA. PMA does not activate the enzymes of the remodeling pathway. We conclude that both remodeling and the de novo pathway for PAF synthesis are present in HUVEC and might be alternatively activated depending on the conditions of cell stimulation.
authors.affiliation: Department of Pathological Biochemistry, Medical Academy, Erfurt, Federal Republic of Germany.
authors.forename: R
authors.initials: R
authors.lastname: Heller
authors.forename: F
authors.initials: F
authors.lastname: Bussolino
authors.forename: D
authors.initials: D
authors.lastname: Ghigo
authors.forename: G
authors.initials: G
authors.lastname: Garbarino
authors.forename: G
authors.initials: G
authors.lastname: Pescarmona
authors.forename: U
authors.initials: U
authors.lastname: Till
authors.forename: A
authors.initials: A
authors.lastname: Bosia
mesh_terms: D000085:Acetates / Q000378:metabolism; D000123:Acetyltransferases / Q000378:metabolism*; D001095:Arachidonic Acids / Q000378:metabolism; D002478:Cells, Cultured; D002794:Choline / Q000378:metabolism; D002798:Diacylglycerol Cholinephosphotransferase; D004229:Dithiothreitol / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D010770:Phosphotransferases / Q000378:metabolism*; D010972:Platelet Activating Factor / Q000096:biosynthesis*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013917:Thrombin / Q000494:pharmacology; D014471:Umbilical Veins
chemical_list: D000085:Acetates; D001095:Arachidonic Acids; D010972:Platelet Activating Factor; D000123:Acetyltransferases; C046035:1-alkylglycerophosphocholine acetyltransferase; D010770:Phosphotransferases; D002798:Diacylglycerol Cholinephosphotransferase; D013917:Thrombin; D002794:Choline; D013755:Tetradecanoylphorbol Acetate; D004229:Dithiothreitol