Evidence for 15-HETE synthesis by human umbilical vein endothelial cells.
Incubation of cultured human umbilical vein endothelial cells with [1-14C]-arachidonic acid, followed by RP-HPLC analysis, resulted in the appearance of two principal radioactive products besides 6-keto-PGF1 alpha. The first peak was HHT, a hydrolysis product of the prostaglandin endoperoxide. The second peak was esterified, converted to the trimethylsilyl ether derivative, and analyzed by GC/MS and was shown to be the lipoxygenase product 15-HETE. Stimulation of endothelial cells with thrombin enhanced 15-HETE synthesis from arachidonate. Subsequent experiments showed that 5-HETE and 12-HETE were also synthesized by endothelial cells, but no evidence of leukotriene synthesis was found. Incubation of the 15-HETE precursor 15-HPETE with endothelial cells resulted in the formation of four distinct ultraviolet light-absorbing peaks. Ultraviolet and GC/MS analysis showed these peaks to be 8,15-diHETEs that differed only in their hydroxyl configuration and cis-trans double-bond geometry. Formation of 8,15-diHETE molecules suggests the prior formation of the unstable epoxide molecule 14,15-LTA4 or an attack at C-10 of 15-HPETE by an enzyme with mechanistic features in common with a 12-lipoxygenase. The observation that endothelial cells can synthesize both 15-HETE and 8,15-diHETE molecules suggest that this cell type contains both a 15-lipoxygenase and a system that can synthesize 14,15-LTA4.
D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D002849:Chromatography, Gas; D004727:Endothelium / Q000166:cytology / Q000378:metabolism; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis*; D013329:Structure-Activity Relationship; D014470:Umbilical Cord / Q000098:blood supply*; D014680:Veins / Q000378:metabolism
D001095:Arachidonic Acids; D006893:Hydroxyeicosatetraenoic Acids; D016718:Arachidonic Acid; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid