Centre for Muscle Metabolism and Biophysics, Department of Community Health Sciences, Brock University, St. Catharines, ON, Canada.
J Membr Biol. 2011 Nov;244(2):97-103. doi: 10.1007/s00232-011-9401-7. Epub 2011 Nov 4.
Generalized membrane lipid composition determinants of fluidity have been widely investigated, including phospholipid/cholesterol ratio and unsaturation index. Individual phospholipids differ in their physical characteristics, including their interaction with cholesterol and level of unsaturation, emphasizing the importance of examining their individual influence on membrane fluidity. Thus, the purpose of this study was to examine the dominant phospholipids of biological membranes (phosphatidylcholine, PC; phosphatidylethanolamine, PE; sphingomyelin, SM) through a meta-analysis to assess the validity of an inclusive phospholipid fluidity index (PFI = PC/(PE + SM)) as a determinant for membrane fluidity (expressed as polarization of fluorescent probe 1,6 diphenyl-1,3,5-hexatriene) in comparison to previous phospholipid ratios (PC/PE and PC/SM). The results demonstrate that all indices significantly predicted membrane fluidity at 25°C (based on 10-13 data points). In contrast, only PFI approached significance when predicting membrane fluidity at 37°C (P = 0.10 based on five points). As a result, PFI appears to be the only phospholipid index close to significantly predicting membrane fluidity at mammalian physiological temperature. Because this meta-analysis only assessed studies using mammalian membranes, future work should experimentally assess the validity of the PFI utilizing membranes from mammals and a variety of other species and tissues at their respective physiological temperatures.
已经广泛研究了广义膜脂质组成对流动性的决定因素，包括磷脂/胆固醇比和不饱和度指数。不同的磷脂在物理特性上存在差异，包括与胆固醇的相互作用和不饱和程度，这强调了研究它们对膜流动性的单独影响的重要性。因此，本研究通过荟萃分析检查了生物膜的主要磷脂（磷脂酰胆碱，PC；磷脂酰乙醇胺，PE；神经鞘磷脂，SM），以评估综合磷脂流动性指数（PFI=PC/（PE+SM））作为膜流动性（用荧光探针 1,6-二苯基-1,3,5-己三烯的偏振来表示）的决定因素的有效性，与之前的磷脂比（PC/PE 和 PC/SM）进行比较。结果表明，所有指数在 25°C 时均显著预测了膜流动性（基于 10-13 个数据点）。相比之下，当预测 37°C 时的膜流动性时，只有 PFI 接近显著（基于 5 个点，P=0.10）。因此，PFI 似乎是唯一接近显著预测哺乳动物生理温度下膜流动性的磷脂指数。由于本荟萃分析仅评估了使用哺乳动物膜的研究，未来的工作应在各自的生理温度下，利用哺乳动物和各种其他物种和组织的膜，实验评估 PFI 的有效性。
