13 - ( S ) - Hydroxyoctadecadienoic acid ( 13 - HODE ) incorporation and conversion to novel products by endothelial cells 1

13(S)-Hydroxy-[12,133 H]octadecadienoic acid (13HODE), a linoleic acid oxidation product that has vasoactive properties, was rapidly taken up by bovine aortic endothelial cells. Most of the 13-HODE was incorporated into phosphatidylcholine, and 80% was present in the sn -2 position. The amount of 13-HODE retained in the cells gradually decreased, and radiolabeled metabolites with shorter reverse-phase high-performance liquid chromatography retention times (RT) than 13-HODE accumulated in the extracellular fluid. The three major metabolites were identified by gas chromatography combined with mass spectrometry as 11-hydroxyhexadecadienoic acid (11-OH-16:2), 9-hydroxytetradecadienoic acid (9-OH-14:2), and 7-hydroxydodecadienoic acid (7-OH-12:2). Most of the radioactivity contained in the cell lipids remained as 13-HODE. However, some 11OH-16:2 and several unidentified products with longer RT than 13-HODE were detected in the cell lipids. Normal human skin fibroblasts also converted 13-HODE to the three major chain-shortened metabolites, but Zellweger syndrome fibroblasts produced only a very small amount of 11-OH16:2. Therefore, the chain-shortened products probably are formed primarily by peroxisomal b -oxidation. These findings suggest that peroxisomal b -oxidation may constitute a mechanism for the inactivation and removal of 13HODE from the vascular wall. Because this is a gradual process, some 13-HODE that is initially incorporated remains in endothelial phospholipids, especially phosphatidylcholine. This may be the cause of some of the functional perturbations produced by 13-HODE in the vascular wall. —Fang, X., T. L. Kaduce, and A. A. Spector. 13-(S)-Hydroxyoctadecadienoic acid (13-HODE) incorporation and conversion to novel products by endothelial cells. J. Lipid Res. 1999. 40: 699–707. Supplementary key words linoleic acid • peroxisomes • phosphatidylcholine • fibroblasts • Zellweger syndrome • lipoxygenase • oxidation 13-Hydroxyoctadecadienoic acid (13-HODE) is produced when linoleic acid is oxidized by either 15-lipoxygenase or cyclooxygenase. 13-Hydroperoxyoctadecadienoic acid (13HPODE) is formed by these oxidative reactions, but a selenium-containing glutathione peroxidase very efficiently reduces the hydroperoxy group and 13-HODE is the product that accumulates when cells or tissues oxidize linoleic acid. Only the S-enantiomer of 13-HODE is produced in the 15-lipoxygenase reaction (1), whereas a mixture of the Rand S-enantiomers of 13-HODE and the positional isomer, 9-hydroxyoctadecadienoic acid (9-HODE), are formed when linoleic acid is oxidized by cyclooxygenase (2). Many different types of cells can convert linoleic acid to 13-HODE. These include polymorphonuclear leukocytes (3), eosinophils (4), bronchiolar lavage cells (5), breast carcinoma cells (6), Syrian hamster embryo fibroblasts (7), and human dermal fibroblasts (8). 13-HODE produces a number of responses in these and other mammalian cells, suggesting that it acts as an autacrine and paracrine lipid mediator. It potentiates the mitogenic signal generated by epidermal growth factor in BT-20 human breast carcinoma cells and Syrian hamster embryo fibroblasts (6, 9), is chemotactic for polymorphonuclear leukocytes (10), is a ligand for the peroxisome proliferator-activated receptor (PPAR) g (11), and can cause an influx of calcium into smooth muscle cells (12). 13-HODE also has potentially important effects in the vascular system. Endothelial cells produce 13-HODE (2, 13–15), and the endothelium is a target of 13-HODE action (16–18). For example, 13-HODE functions as a chemorepellant, reducing the adhesion of platelets and melanoma cells to the endothelial surface (13, 16, 17), and it increases prostaglandin I 2 production by the endothelial cells (18). Studies with vascular preparations indicate that Abbreviations: 13-HODE, 13-hydroxyoctadecadienoic acid; 13HPODE, 13-hydroperoxyoctadecadienoic acid; 9-HODE, 9-hydroxyoctadecadienoic acid; PPAR, peroxisome proliferator activated receptor; BAEC, bovine aortic endothelial cells; HEPES, 4-(2-hydroxyethyl-Opiperazine-ethane sulfonic acid; FBS, fetal bovine serum; [ 3 H]-13HODE, [12,133 H]13-HODE; TLC, thin layer chromatography; HPLC, high-performance liquid chromatography; GC/MS, gas chromatography and mass spectrometry; RT, retention time; 11-OH-16:2, 11-hydroxyhexadecadienoic acid; 9-OH-14:2, 9-hydroxytetradecadienoic acid; 7-OH-12:2, 12-hydroxydodecadienoic acid; HETE, hydroxyeicosatetraenoic acid. 1 Dr. Godfrey Getz served as guest editor for this article. 2 To whom correspondence should be addressed. by gest, on A uust 7, 2017 w w w .j.org D ow nladed fom