Studies on the mechanism of interleukin 1 stimulation of platelet activating factor synthesis in human endothelial cells in culture.
Interleukin 1 promotes the conversion of the biologically inactive lyso-platelet activating factor (lyso-PAF) to the bioactive platelet activating factor (PAF) by an acetylation reaction in cultured human endothelial cells. After 2 h stimulation with interleukin 1, 1-O-alkyl-2-lysoglycero-3-phosphocholine (GPC): acetyl CoA acetyltransferase is activated, reaching a plateau after 6 h and then declining to the basal value within 24 h. This time course is comparable to that of PAF production. These cells are able to incorporate [3H]acetate and [3H]lyso-PAF into PAF. Synthetized [3H]PAF is then catabolized in [3H]alkylacyl phosphoglycerides. 1-O-alkyl-2-acetylglycerol: CDP-choline cholinephosphotransferase and 1-O-alkyl-2-acetyl-GPC: acetylhydrolase activities are both present in endothelial cells, but are not activated under our conditions of stimuli. These findings indicate that interleukin 1 induces the PAF synthesis by a deacylation/reacetylation mechanism into human endothelial cells.
D000085:Acetates / Q000378:metabolism; D000107:Acetylation; D000123:Acetyltransferases / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002478:Cells, Cultured; D002798:Diacylglycerol Cholinephosphotransferase / Q000378:metabolism; D004727:Endothelium / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology*; D007700:Kinetics; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000096:biosynthesis* / Q000378:metabolism; D014471:Umbilical Veins
D000085:Acetates; D007375:Interleukin-1; C029271:O-deacetyl platelet activating factor; D010972:Platelet Activating Factor; D000123:Acetyltransferases; C027628:acetyl-CoA-1-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase; D002798:Diacylglycerol Cholinephosphotransferase; C028207:1-alkyl-2-acetyl-sn-glycero-3-phosphocholine-acetylhydrolase; D002265:Carboxylic Ester Hydrolases