Deng Yuru, Almsherqi Zakaria A, Shui Guanghou, Wenk Markus R, Kohlwein Sepp D
Department of Physiology, National University of Singapore, Singapore.
FASEB J. 2009 Sep;23(9):2866-71. doi: 10.1096/fj.09-130435. Epub 2009 Apr 30.
Very long-chain polyunsaturated fatty acids (VLC-PUFAs), such as docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA), have recently made it to the realm of "magical molecules" based on their multiple presumably beneficial effects in biological systems, making these PUFAs particularly interesting in biomedicine. Their specific biological functions, however, remain enigmatic. Here we provide evidence derived from studies in the amoeba Chaos that indicates a structural role for omega-6 DPA in cell membrane organization, which may help to explain the multiple diverse effects of VLC-PUFA in healthy and diseased states. Amoeba Chaos mitochondria undergo a remarkable and reversible morphological transition into cubic morphology on starvation. This morphological transition is reflected in major changes in fatty acid and lipid composition, as determined by gas liquid chromatography and mass spectrometry, in particular by a drastic increase in C22:5 modified phosphatidylcholine plasmalogen, phosphatidylethanolamine plasmalogen, and phosphatidylinositol species. Liposomes produced in vitro from lipids of starved amoeba cells show a high propensity to form hexagonal tubular and cubic morphologies. Addition of omega-6 DPA, but not of omega-3 DPA, to the cell culture also induced mitochondrial membrane transformation into cubic morphology in fed cells, demonstrating for the first time an important structural role of omega-6 DPA-containing lipids in cell membrane organization.
超长链多不饱和脂肪酸（VLC-PUFAs），如二十二碳六烯酸（DHA）和二十二碳五烯酸（DPA），由于其在生物系统中可能具有多种有益作用，最近已进入“神奇分子”的领域，这使得这些多不饱和脂肪酸在生物医学中特别引人关注。然而，它们的具体生物学功能仍然是个谜。在此，我们提供了来自对变形虫混沌菌研究的证据，表明ω-6 DPA在细胞膜组织中具有结构作用，这可能有助于解释VLC-PUFA在健康和疾病状态下的多种不同作用。变形虫混沌菌的线粒体在饥饿时会经历显著且可逆的形态转变，变为立方形态。这种形态转变反映在脂肪酸和脂质组成的主要变化中，通过气相色谱法和质谱法测定，特别是C22:5修饰的磷脂酰胆碱缩醛磷脂、磷脂酰乙醇胺缩醛磷脂和磷脂酰肌醇种类大幅增加。用饥饿变形虫细胞的脂质在体外制备的脂质体显示出形成六边形管状和立方形态的高度倾向。在细胞培养中添加ω-6 DPA而非ω-3 DPA，也会诱导进食细胞中的线粒体膜转变为立方形态，首次证明了含ω-6 DPA的脂质在细胞膜组织中的重要结构作用。
