The mitogenic effect of 15- and 12-hydroxyeicosatetraenoic acid on endothelial cells may be mediated via diacylglycerol kinase inhibition.
15-Hydroxyeicosatetraenoic acid (15-HETE), a major lipoxygenase metabolite of arachidonic acid in fetal bovine aortic endothelial cells, was a mitogen for these cells, stimulating both cell proliferation and DNA synthesis in the presence of serum and serum-deprived cells. In [14C]arachidonic acid-labeled confluent endothelial cell monolayers, 15-HETE (30 microM) caused an elevation of [14C]diacylglycerol (DAG) with a concomitant decrease in cellular [14C]phosphatidylinositol (PI) in both unstimulated and stimulated cells. 1-Oleoyl-2-acetylglycerol, a synthetic DAG analog, stimulated endothelial cell DNA synthesis in a concentration-dependent manner. In [3H]inositol-labeled cells, 15-HETE also caused a decrease in cellular PI content under both basal and stimulated conditions. 15-HETE, however, had no effect on either isolated phospholipase C activity or phosphoinositide turnover in lithium chloride-treated cells. In intact cells, 15-HETE (30 microM) inhibited the synthesis of [3H]PI from [3H]inositol (80% inhibition, p less than 0.001). In human red cell membranes, the production of phosphatidic acid from endogenous DAG was inhibited by 15-HETE in a concentration-dependent manner with an IC50 of 41 microM. Although 12-HETE had effects similar to those of 15-HETE, the parent compound arachidonic acid did not affect DNA synthesis or DAG kinase activity. Our study thus demonstrates that the mitogenic activity of 15- and 12-HETE on endothelial cells may be mediated via DAG kinase inhibition with the concomitant accumulation of cellular DAG.
Setty
B N
BN
Department of Pediatrics, State University of New York, Syracuse 13210.
Graeber
J E
JE
Stuart
M J
MJ
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D019852:Diacylglycerol Kinase; D004075:Diglycerides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects; D006893:Hydroxyeicosatetraenoic Acids / Q000494:pharmacology*; D007213:Indomethacin / Q000494:pharmacology; D008938:Mitosis / Q000187:drug effects*; D010770:Phosphotransferases / Q000037:antagonists & inhibitors*; D013936:Thymidine / Q000378:metabolism
D001095:Arachidonic Acids; D004075:Diglycerides; D006893:Hydroxyeicosatetraenoic Acids; D015117:5,8,11,14-Eicosatetraynoic Acid; D016718:Arachidonic Acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; C038237:1-oleoyl-2-acetylglycerol; D010770:Phosphotransferases; D019852:Diacylglycerol Kinase; D013936:Thymidine; D007213:Indomethacin