title: [Deposition of exogenous and endogenously generated unsaturated fatty acids in lipid droplets triacylglycerol as a mechanism of its sequestration in epithelial cells].
abstract: Neutral lipids are deposited in intracellular compartments called lipid droplets, which are known to be critically implicated in regulation of cellular lipid metabolism. These organelles consist of a core of neutral lipids, mainly triacylglycerol (TAG) and cholesteryl esters, surrounded by phospholipid monolayer. Using Nile red lipid staining and [3H]-arachidonic and [3H]-oleic acids as precursors for lipid biosynthesis, we have evaluated the mechanisms of lipid body induction elicited by exogenous fatty acids within primary cultured epithelial cells from the frog urinary bladder. It was found that arachidonic and oleic acids at concentrations 10-50 tM stimulated lipid droplets formation accompanied by accumulation of TAG and by the significant increase of incorporation of fatty acids into TAG indicating an enhanced TAG biosynthesis. No changes of cholesteryl esters content were observed under these conditions. In cells, prelabelled with [3H]-oleic acids, etomoxir, an inhibitor of O-carnitine palmitroyltansferase 1, decreased oxidation of oleic acid and increased its incorporation into TAG leading to intracellular TAG accumulation. In cells, prelabelled with [3H]-arachidonic acid, diclofenac, an inhibitor of cyclooxygenase 1 and 2, led to significant decrease in cellular PGE2 production and to reesterification of free arachidonic acid to TAG but not to phospholipids. Taking together, these data evidence that in isolated frog urinary bladder epithelial cells, reacylation of unsaturated free fatty acids into TAG is a main route of their metabolic conversion under the conditions of the increased cytosolic level of free fatty acids.
authors: E V
authors: EV
authors: Fedorova
authors: E M
authors: EM
authors: Fok
authors: V T
authors: VT
authors: Bakhteeva
authors: E A
authors: EA
authors: Lavrova
authors: R G
authors: RG
authors: Parnova
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D001692:Biological Transport; D002334:Carnitine O-Palmitoyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism; D051545:Cyclooxygenase 1 / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004008:Diclofenac / Q000494:pharmacology; D015232:Dinoprostone / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004852:Epoxy Compounds / Q000494:pharmacology; D066292:Lipid Droplets / Q000187:drug effects / Q000378:metabolism*; D050356:Lipid Metabolism; D019301:Oleic Acid / Q000378:metabolism*; D061251:Primary Cell Culture; D011896:Rana temporaria; D014280:Triglycerides / Q000096:biosynthesis*; D014316:Tritium; D001743:Urinary Bladder / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019459:Urothelium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002788:Cholesterol Esters; D004791:Enzyme Inhibitors; D004852:Epoxy Compounds; D014280:Triglycerides; D014316:Tritium; D004008:Diclofenac; D016718:Arachidonic Acid; D019301:Oleic Acid; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D002334:Carnitine O-Palmitoyltransferase; D015232:Dinoprostone; C054207:etomoxir