Metabolism of 15-hydroxyeicosatetraenoic acid by Caco-2 cells.
Monolayers of Caco-2 cells, a human enterocyte cell line, were incubated with [1-14C]15-hydroxyeicosatetraenoic acid (15-HETE), a lipid mediator of inflammation, and [1-14C]arachidonic acid. Both fatty acids were taken up readily and metabolized by Caco-2 cells. [1-14C]Arachidonic acid was directly esterified in cellular phospholipids and, to a lesser extent, in triglycerides. When [1-14C]15-hydroxyeicosatetraenoic acid was incubated with Caco-2 cells, about 10% was directly esterified into cellular lipids but most (55%) was beta-oxidized to ketone bodies, CO2, and acetate, with very little accumulation of shorter carbon chain products of partial beta-oxidation. The radiolabeled acetate generated from beta-oxidation of [1-14C]15-hydroxyeicosatetraenoic acid was incorporated into the synthesis of new fatty acids, primarily [14C]palmitate, which in turn was esterified into cellular phospholipids, with lesser amounts in triglycerides. Caco-2 cells were also incubated with [5,6,8,9,11,12,14,15-3H]15-hydroxyeicosatetraenoic acid; most of the radiolabel was recovered either in ketone bodies or in [3H]palmitate esterified in phospholipids and triglycerides, demonstrating that most of the [3H]15-hydroxyeicosatetraenoic acid underwent several cycles of beta-oxidation. The binding of both 15-hydroxyeicosatetraenoic acid and arachidonic acid to hepatic fatty acid binding protein, the only fatty acid binding protein in Caco-2 cells, was measured. The Kd (6.0 microM) for 15-HETE was three-fold higher than that for arachidonate (2.1 microM).
Riehl
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Division of Gastroenterology, Jewish Hospital of St. Louis, MO 63110.
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Stenson
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D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D004848:Epithelium / Q000378:metabolism; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism*; D015212:Inflammatory Bowel Diseases / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D009363:Neoplasm Proteins; D010084:Oxidation-Reduction; D025521:Tumor Suppressor Proteins
D001095:Arachidonic Acids; D002352:Carrier Proteins; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D006893:Hydroxyeicosatetraenoic Acids; D009363:Neoplasm Proteins; D025521:Tumor Suppressor Proteins; D016718:Arachidonic Acid; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid