Effect of phospholipid fatty acid composition of endothelial cells on cholesterol efflux rates.
Human endothelial cells (EA.hy 926 line) were loaded with cationized low density lipoprotein (LDL) and subsequently incubated with fatty acid/bovine serum albumin complexes. The fatty acids were palmitic, oleic, linoleic, arachidonic, and eicosapentaenoic acids. The preincubations resulted in extensively modified fatty acid profiles in cell membrane phospholipids and in cellular cholesteryl esters. The cholesterol efflux from these fatty acid-modified cells was measured using 0.2 mg high density lipoprotein3 (HDL3)/ml medium. The efflux was significantly higher for the palmitic acid-treated cells, compared to all other fatty acid treatments. These differences in efflux rates were not caused by changes in the binding of HDL3 to high affinity receptors on the EA.hy 926 cells. Efflux mediated by dimethyl suberimidate-treated HDL3, which does not interact with high affinity HDL receptors, was similar to efflux induced by native HDL3 after all fatty acid treatments. Our results indicate that high affinity HDL receptors are not important for HDL-mediated efflux of cell cholesterol. The fatty acid composition of the cell membrane phospholipids may be an important determinant.
Kilsdonk
E P
EP
Department of Biochemistry, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, The Netherlands.
Dorsman
A N
AN
van Gent
T
T
van Tol
A
A
D001057:Apolipoproteins E / Q000378:metabolism; D016718:Arachidonic Acid / Q000494:pharmacology; D002412:Cations; D002460:Cell Line; D002477:Cells; D002784:Cholesterol / Q000378:metabolism*; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D005227:Fatty Acids / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000494:pharmacology; D008075:Lipoproteins, HDL / Q000378:metabolism / Q000494:pharmacology; D053440:Lipoproteins, HDL3; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008563:Membrane Lipids / Q000378:metabolism*; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000494:pharmacology
D001057:Apolipoproteins E; D002412:Cations; D005227:Fatty Acids; D008041:Linoleic Acids; D008075:Lipoproteins, HDL; D053440:Lipoproteins, HDL3; D008077:Lipoproteins, LDL; D008563:Membrane Lipids; D009829:Oleic Acids; D010169:Palmitic Acids; D016718:Arachidonic Acid; D019301:Oleic Acid; D019308:Palmitic Acid; D002784:Cholesterol; D019787:Linoleic Acid; D015118:Eicosapentaenoic Acid