Cader A A, Butterfield D A, Watkins B A, CHung B H, Hennig B
Department of Nutrition and Food Science, University of Kentucky, Lexington, USA.
Int J Biochem Cell Biol. 1995 Jul;27(7):665-73. doi: 10.1016/1357-2725(95)00036-o.
Endothelial cell dysfunction has been implicated in the development of atherosclerosis. Of vital importance to the maintenance of endothelial cell integrity is the preservation of membrane functional and structural properties, such as membrane fluidity. The aim of this study was to develop a model for studying the relationship between endothelial cell integrity and membrane fluidity alterations in a well-defined cell culture setting. Alterations in membrane fluidity were assessed using electron spin resonance after labeling endothelial cells with the lipid-specific spin labels, CAT-16 and 12-nitroxide stearic acid. Endothelial cells were exposed to various 18-carbon fatty acids, i.e. stearic (18:0), oleic (18:1), linoleic (18:2), or linolenic (18:3), in addition to lipolyzed HDL (L-HDL) and benzyl alcohol. Membrane phospholipid fatty acid composition of endothelial cells supplemented with these fatty acids was analyzed using gas chromatography. All fatty acids, except 18:0, decreased membrane fluidity. A relationship between membrane fluidity and fatty acid compositional alterations in cellular phospholipids was observed. In particular, the arachidonic acid content decreased following exposure to 18:1, 18:2, or 18:3. Exposure of endothelial cells to L-HDL, lipoprotein particles which contain high levels of 18:1 and 18:2, also decreased membrane fluidity. The stabilization of cytoskeletal actin filaments by phalloidin partially prevented 18:2-induced increases in albumin transfer, thus implicating a cytoskeletal involvement in the 18:2-induced membrane fluidity changes involved in endothelial cell dysfunction. The present study shows that the exposure of endothelial cells to various lipids causes membrane fluidity alterations which may contribute to endothelial cell dysfunction and atherosclerosis.
内皮细胞功能障碍与动脉粥样硬化的发展有关。对于维持内皮细胞完整性至关重要的是保持膜的功能和结构特性，如膜流动性。本研究的目的是建立一个模型，用于在明确的细胞培养环境中研究内皮细胞完整性与膜流动性改变之间的关系。在用脂质特异性自旋标记物CAT - 16和12 - 硝基硬脂酸标记内皮细胞后，使用电子自旋共振评估膜流动性的改变。除了脂解高密度脂蛋白（L - HDL）和苯甲醇外，内皮细胞还暴露于各种18碳脂肪酸，即硬脂酸（18:0）、油酸（18:1）、亚油酸（18:2）或亚麻酸（18:3）。使用气相色谱法分析补充这些脂肪酸的内皮细胞膜磷脂脂肪酸组成。除18:0外，所有脂肪酸均降低了膜流动性。观察到膜流动性与细胞磷脂中脂肪酸组成改变之间的关系。特别是，暴露于18:1、18:2或18:3后，花生四烯酸含量降低。内皮细胞暴露于L - HDL（含有高水平18:1和18:2的脂蛋白颗粒）也降低了膜流动性。鬼笔环肽对细胞骨架肌动蛋白丝的稳定作用部分阻止了18:2诱导的白蛋白转运增加，从而表明细胞骨架参与了18:2诱导的与内皮细胞功能障碍相关的膜流动性变化。本研究表明，内皮细胞暴露于各种脂质会导致膜流动性改变，这可能导致内皮细胞功能障碍和动脉粥样硬化。
