Differential effects of conjugated linoleic acid isomers on macrophage glycerophospholipid metabolism.
Conjugated linoleic acids (CLA) are dietary fatty acids. Whereas cis-9,trans-11-(c9,t11)-CLA can be found in meat and dairy products, trans-9,trans-11-(t9,t11)-CLA is a constituent of vegetable oils. Previous studies showed that these two isomers activate different nuclear receptors and, thus, expression of genes related to lipid metabolism. Here we show that these CLA isomers are differentially elongated and desaturated in primary monocyte-derived macrophages isolated from healthy volunteers by using gas chromatography-mass spectrometry (GC-MS). We further demonstrate that c9,t11-CLA incorporates in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) species and activates de novo glycerophospholipid synthesis by quantitative electrospray ionization-tandem mass spectrometry (ESI-MS/MS). c9,t11-CLA leads to strong shifts of the species profiles to PC 18:2/18:2 and PE 18:2/18:2, which are due to de novo synthesis and fatty acid remodeling. In contrast, t9,t11-CLA is preferentially bound to neutral lipids, including triglycerides and cholesterol esters. Taken together our results show that c9,t11-CLA and t9,t11-CLA have differential effects on PC and PE metabolism. Moreover, these data demonstrate that the structure of fatty acids not only determines their incorporation into lipid classes but also modulates the kinetics of lipid metabolism, particularly PC synthesis.
Institute of Clinical Chemistry and Laboratory Medicine, University of Regensburg, Regensburg, Germany.
Josef
J
Ecker
Gerhard
G
Liebisch
Max
M
Scherer
Gerd
G
Schmitz
D002478:Cells, Cultured; D004041:Dietary Fats; D005227:Fatty Acids / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D020404:Glycerophospholipids / Q000378:metabolism*; D006801:Humans; D007536:Isomerism; D044243:Linoleic Acids, Conjugated / Q000737:chemistry* / Q000494:pharmacology*; D050356:Lipid Metabolism / Q000187:drug effects*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000737:chemistry / Q000378:metabolism
D004041:Dietary Fats; D005227:Fatty Acids; D020404:Glycerophospholipids; D044243:Linoleic Acids, Conjugated; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; C046938:9,11-linoleic acid; C483858:phosphatidylethanolamine