Switching of the core structures of glycosphingolipids from globo- and lacto- to ganglio-series upon human embryonic stem cell differentiation
Switching of the core structures of glycosphingolipids from globo- and lacto- to ganglio-series upon human embryonic stem cell differentiation
复制标题
DOI：
10.1073/pnas.1007290108
复制
发表时间：
2010-12-28
影响因子：
11.1
通讯作者：
Yu, John
中科院分区：
文献类型：
--
作者：
Liang, Yuh-Jin;Kuo, Huan-Hsien;Yu, John
采用免疫荧光、流式细胞术、MALDI-MS和MS/MS分析方法，对两个hESC系及其分化的三胚层胚状体（EB）的鞘糖脂（GSL）表达谱进行了系统的研究。除了众所周知的hESC特异性标志物阶段特异性胚胎抗原3（SSEA-3）和SSEA-4外，我们还鉴定了几种以前在hESC中未发现的globosides和lacto-series GSL，包括Gb（4）Cer、Lc（4）Cer、岩藻糖基Lc（4）Cer、Globo H和二唾液酸基Gb（5）Cer。在hESC分化成EB的过程中，MS分析揭示了GSL的核心结构从球蛋白和乳蛋白到神经节系列的明确转换，这在用针对SSEA-3和SSEA-4的抗体进行免疫染色时并不明显，这是由于它们与各种鞘糖脂的交叉反应性。这样的开关是由于改变表达的关键糖基转移酶（GT）的生物合成途径的上调神经节系列相关的GT与同时下调球和乳糖系列相关的GT。因此，这些结果提供了独特的阶段特异性的过渡和机制的GSL核心结构在hESC分化过程中的改变的见解。此外，通过MS分析发现的独特聚糖结构可以作为进一步描绘hESC的表面标志物，并有助于鉴定其不仅在hESC中而且在癌症中的功能作用。
A systematic survey of expression profiles of glycosphingolipids (GSLs) in two hESC lines and their differentiated embryoid body (EB) outgrowth with three germ layers was carried out using immunofluorescence, flow cytometry, and MALDI-MS and MS/MS analyses. In addition to the well-known hESC-specificmarkers stage-specific embryonic antigen 3 (SSEA-3) and SSEA-4, we identified several globosides and lacto-series GSLs, previously unrevealed in hESCs, including Gb(4)Cer, Lc(4)Cer, fucosyl Lc(4)Cer, Globo H, and disialyl Gb(5)Cer. During hESC differentiation into EBs, MS analysis revealed a clear-cut switch in the core structures of GSLs from globo- and lacto-to ganglio-series, which was not as evident by immunostaining with antibodies against SSEA-3 and SSEA-4, owing to their cross-reactivities with various glycosphingolipids. Such a switch was attributable to altered expression of key glycosyltransferases (GTs) in the biosynthetic pathways by the up-regulation of ganglio-series-related GTs with simultaneous down-regulation of globo-and lacto-series-related GTs. Thus, these results provide insights into the unique stage-specific transition and mechanism for alterations of GSL core structures during hESC differentiation. In addition, unique glycan structures uncovered by MS analyses may serve as surface markers for further delineation of hESCs and help identify of their functional roles not only in hESCs but also in cancers.