Mass and relative elution time profiling: two-dimensional analysis of sphingolipids in Alzheimer's disease brains
Mass and relative elution time profiling: two-dimensional analysis of sphingolipids in Alzheimer's disease brains
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DOI：
10.1042/bj20110566
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发表时间：
2011-08-15
影响因子：
4.1
通讯作者：
Don, Anthony S.
中科院分区：
文献类型：
--
作者：
Hejazi, Leila;Wong, Jason W. H.;Don, Anthony S.
目前的脂肪组谱分析方法主要依靠MS来鉴定复杂样品中的未知脂类。我们描述了一种新的方法，包括基于质量和疏水性的鞘磷脂的LC-MS/MS(LC-MS/MS)分析，并用该方法表征AD(阿尔茨海默病)和对照组海马神经鞘磷脂(SM)、神经酰胺和半乳糖神经酰胺(GalCer)的含量。利用数学关系，我们排除了鞘脂质量对保留时间的影响，并生成了有助于准确可视化和表征给定鞘脂类别中不同神经酰胺部分的二维曲线图，因为相关分子在曲线图上水平或垂直排列。根据疏水性很容易区分质量仅相差0.04Da的主要脑GalCer物种。我们的方法能够定义大脑样本中所有主要的GalCer物种的重要性被新的观察结果所证明，与年龄和性别匹配的对照组相比，AD患者海马区含有羟基化脂肪酸的GalCer比例增加了大约2倍。这表明脂肪酸羟基酶在AD中被激活。我们的方法极大地提高了脂类实验中获得的数据的清晰度，并可以扩展到其他脂类。
Current lipidomic profiling methods rely mainly on MS to identify unknown lipids within a complex sample. We describe a new approach, involving LC x MS/MS (liquid chromatography x tandem MS) analysis of sphingolipids based on both mass and hydrophobicity, and use this method to characterize the SM (sphingomyelin), ceramide and GalCer (galactosylceramide) content of hippocampus from AD (Alzheimer's disease) and control subjects. Using a mathematical relationship we exclude the influence of sphingolipid mass on retention time, and generate two-dimensional plots that facilitate accurate visualization and characterization of the different ceramide moieties within a given sphingolipid class, because related molecules align horizontally or vertically on the plots. Major brain GalCer species that differ in mass by only 0.04 Da were easily differentiated on the basis of their hydrophobicity. The importance of our method's capacity to define all of the major GalCer species in the brain samples is illustrated by the novel observation that the proportion of GalCer with hyclroxylated fatty acids increased approximately 2-fold in the hippocampus of AD patients, compared with age- and gender-matched controls. This suggests activation of fatty acid hydroxylase in AD. Our method greatly improves the clarity of data obtained in a lipid profiling experiment and can be expanded to other lipid classes.