Differential effects of conjugated linoleic acid isomers on the biophysical and biochemical properties of model membranes

作者：Subbaiah Papasani V^*; Sircar Debajit; Aizezi Buzulagu; Mintzer Evan

来源：Biochimica et Biophysica Acta-Biomembranes, 2010, 1798(3): 506-514.

DOI：10.1016/j.bbamem.2009.11.020

• Conjugated linoleic acid
• Phosphatidylcholine
• Monolayer property
• Membrane fluidity
• Cholesterol-binding
• Membrane permeability

Conjugated linoleic acids (CIA) are known to exert several isomer-specific biological effects, but their mechanisms of action are unclear. In order to determine whether the physicochemical effects of CLA on membranes play a role in their isomer-specific effects, we synthesized phosphatidylcholines (PCs) with 16:0 at sn-1 position and one of four CIA isomers (trans 10 cis 12 (A), trans 9 trans 11 (B), cis 9 trans 11 (C), and cis 9 cis I I (D)) at sn-2, and determined their biophysical properties in monolayers; and bilayers. The surface areas of the PCs with the two natural CLA (A and Q were similar at all pressures, but they differed significantly in the presence of cholesterol, with PC-A condensing more than PC-C. Liposomes of PC-A similarly showed increased binding of cholesterol compared to PC-C liposomes. PC-A liposomes were less permeable to carboxyfluorescein compared to PC-C liposomes. The PC with two trans double bonds (B) showed the highest affinity to cholesterol and lowest permeability. The two natural CLA-PCs (A and Q stimulated lecithin-cholesterol acyltransferase activity by 2-fold, whereas the unnatural CLA-PCs (B and D) were inhibitory. These results suggest that the differences in the biophysical properties of CIA isomers A and C may partly contribute to the known differences in their biological effects.

• 出版日期2010-3