title: Activation of 15-lipoxygenase by low density lipoprotein in vascular endothelial cells. Relationship to the oxidative modification of low density lipoprotein.
abstract: Oxidatively-modified low density lipoprotein (LDL) is thought to play a significant role in the formation of lipid-laden macrophages, the primary cellular component of atherosclerotic fatty lesions. Recently, lipoxygenases have been implicated as a major enzymatic pathway involved in rabbit endothelial cell-mediated LDL modification. We investigated the effect of LDL on porcine aortic endothelial cell (PAEC) and human umbilical vein (HUVEC) and aortic endothelial cell (HAEC) lipoxygenase activity. By thin layer chromatography, we observed that human LDL stimulated the metabolism of radiolabeled arachidonic acid to 12 + 15-hydroxyeicosatetraenoic acid (HETE) in indomethacin-treated PAEC. Furthermore, radiolabeled linoleic acid, a specific substrate for the 15-lipoxygenase, was metabolized to its respective product 13-hydroxyoctadecadienoic acid (13-HODE) in the presence of LDL. Increased product formation in both studies was inhibited by the lipoxygenase blockers nordihydroguaiaretic acid (NDGA) and RG 6866. 15-HETE was confirmed as the predominant HETE product in LDL-treated cells by high performance liquid chromatography. Both porcine- and human-derived LDL stimulated the CL release of 15-HETE from cells as determined by radioimmunoassay. Release of immunoreactive 15-HETE was inhibited by NDGA, RG 6866, and 5,8,11,14-eicosatetraynoic acid (ETYA) but not by the selective 5-lipoxygenase inhibitor RG 5901. These lipoxygenase inhibitors had similar effects on the modification of LDL. Our results suggest that the oxidative modification of LDL by endothelial cells may be mediated in part through activation of 15-lipoxygenase.
authors.affiliation: Department of Cardiovascular Pharmacology, Rhône-Poulenc Rorer Central Research, King of Prussia, Pennsylvania 19406.
authors.forename: C K
authors.initials: CK
authors.lastname: Derian
authors.forename: D F
authors.initials: DF
authors.lastname: Lewis
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D000818:Animals; D001011:Aorta; D001093:Arachidonate 15-Lipoxygenase / Q000378:metabolism*; D001593:Benzyl Compounds / Q000494:pharmacology; D002478:Cells, Cultured; D003300:Copper / Q000494:pharmacology; D019327:Copper Sulfate; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D006877:Hydroxamic Acids / Q000494:pharmacology; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis; D007213:Indomethacin / Q000494:pharmacology; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000096:biosynthesis / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism / Q000494:pharmacology*; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology*; D009637:Masoprocol / Q000494:pharmacology; D010084:Oxidation-Reduction; D011804:Quinolines / Q000494:pharmacology; D013552:Swine; D014471:Umbilical Veins
chemical_list: D001593:Benzyl Compounds; D006877:Hydroxamic Acids; D006893:Hydroxyeicosatetraenoic Acids; D008041:Linoleic Acids; D008077:Lipoproteins, LDL; D016859:Lipoxygenase Inhibitors; D011804:Quinolines; C049740:alpha-pentyl-3-(2-quinolinylmethoxy)benzenemethanol; D015117:5,8,11,14-Eicosatetraynoic Acid; C061590:RG 6866; C024348:13-hydroxy-9,11-octadecadienoic acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D003300:Copper; D009637:Masoprocol; D019787:Linoleic Acid; D001093:Arachidonate 15-Lipoxygenase; D019327:Copper Sulfate; D007213:Indomethacin