- 學位論文
硫酸化醣質體之奈米液相層析串聯式質譜分析技術的研發與應用
Development and Applications of Negative Ion Mode nanoLC−MS/MS-Based Sulfoglycomics
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摘要
醣質體質譜分析平台期望能全盤性的分析在特定的病理以及生理狀況下，細胞或組織的醣類組成。目前已知硫酸化修飾的醣類參與許多重要的生物進程，然而由於硫酸化修飾的醣類很微量並且不易被游離化，常常無法被現行的醣質體質譜分析平台偵測，因此，在本研究中我們將醣質體質譜分析平台，從現行的基質輔助雷射脫附離子化質譜為基礎的分析流程加以延伸並進展到更先進的電噴灑離子化質譜為基礎的分析，期望能提升偵測的極限。本實驗室在之前已經建立利用陰離子交換固相萃取法，有效的萃取全甲基化硫酸化的醣類，因此當我們在負電模式下使用電噴灑離子化質譜為基礎的質譜分析搭配陰離子交換固相萃取法實際應用來分析人工培養的人類支氣管上皮細胞，我們發現帶有兩個硫酸基的醣類會帶兩個電荷，並且使其被偵測的敏感度提升，此外，當我們在前端搭載了奈米液相層析管柱更可以提升偵測敏感度以及增加進樣的樣品量，使我們可以得到更多的斷片圖譜。並且我們也藉由一系列的標準品以及萃取自人工培養的人類支氣管上皮細胞的醣類，系統性地探討由高能誘導裂解技術以及碰撞誘導裂解技術所產生出來的斷片，找出了其中最具有代表性的斷片。另外，我們也在此研究中展現在負電模式下使用奈米液相層析-質譜分析技術時，若同時使用高能誘導裂解技術以及碰撞誘導裂解技術配搭特徵子代離子控制三次質譜斷裂，可以有效的分析全甲基化後各式各樣帶有鹽藻醣或唾液酸的硫酸化醣結構之同分異構物，並在研究中展現如何應用這些分析結果，而這些我們人工確認過的資料組，每一個都有不同的質/荷數字，分別代表著不同的醣類結構組成，將來都可以在軟體開發上當作很好的參考依據。除此之外，當我們利用我們所建立的方法來分析老鼠以及人類的嗜酸性球，我們發現了一種用基質輔助雷射脫附離子化質譜為基礎的分析方法所無法偵測到的新奇硫酸化醣類結構，即末端的唾液酸帶有硫酸基的結構，由於之前的研究報導過海膽含有C8位置硫酸化的NeuNAc與NeuGc結構，因此我們更進一步利用從海膽萃取的醣脂來建立鑑定硫酸化唾液酸所需要的的特徵離子。我們也分析了一系列的細胞株以幫助我們更進一步了解細胞表面的硫酸化唾液酸在不同組織的分布情形。另外，為了瞭解醣類硫酸化以及沒有硫酸化的比例，我們也成功的改良氣相層析鍵結分析法將其應用在正電模式下的液相層析質譜中，並且相對定量出在牛的甲狀腺球蛋白中不含硫酸基、帶有一個硫酸基以及兩個硫酸基的醣比例分別為82:13:8。總結來說，透過我們最新開發的奈米液相層析之質譜方法，我們可以得到更多更高敏感度的硫酸化醣質體之定量以及定性的資訊，這些資訊都將提供我們了解有關於硫酸化醣類在生物體中的功能表現以及生理上扮演的重要性。
關鍵字
硫酸化醣質體並列摘要
Mass spectrometry (MS)-based glycomics aims to comprehensively map all the glycan constituents of a cell or tissue under a particular patho-physiological state. Sulfated glycans are known to participate in many important biological processes but often under-detected or represented in MS-based glycomics due to their lower abundance and ionization problems. Thus, in my study, we aim to extend and complement our MALDI-MS and MS/MS-based sulfoglycomic workflow with advanced nanoLC-MS/MS-based strategy to improve the detection limit. By the anion-exchange solid-phase extraction method established previously in our laboratory, permethylated sulfated glycans could be efficiently extracted from the total pool of glycans. After applying the strategy to the cultured human bronchial epithelial cells, we now showed that these can be analyzed by nanoLC-ESI-MS/MS in negative ion mode, which is more conducive than MALDI-MS for sensitive detection of doubly charged di-sulfated glycans. The additional coupling of nanoLC separation prior to MS improves the detection sensitivity and handling capacity for comprehensive analysis, therefore, more MS/MS spectra could be obtained. We have now systematically investigated the most useful fragmentation characteristics afforded by higher energy collision dissociation (HCD) versus ion trap CID, based on a panel of synthetic standards and a complex pool of sulfated glycans derived from cultured human bronchial epithelial cells. We show that an efficient mapping of various isomeric fucosylated, sialylated, sulfated glycotopes by negative ion mode nanoLC-MS/MS analysis of permethylated glycans can benefit from data dependent parallel acquisition of both HCD and ion trap CID MS2, supplemented further by a product ion dependent MS3 scan function, and how the generated data can be productively utilized. The manually verified dataset of over hundred glycan entries, each represented by a distinct m/z value and hence glycosyl composition, additionally serves to guide current development of much needed computational tool for sulfoglycomic data analysis and presentation. When applied to both mouse and human eosinophils, we could observe novel sulfated glycans otherwise not detected by MALDI-based strategy, and additionally identified the occurrence of sulfate on terminal sialic acid. Therefore, we further utilized glycolipid derived from sea urchin, which is already known to contain sulfate at C8 position of NeuNAc and NeuGc to establish the characteristic ion of sulfated sialic acid on mass spectrometry. Moreover, in order to map the occurrence of sulfated sialic acid on the surface of cells in different tissues, series of cell line were applied to do the glycomic analysis. In addition, to evaluate the ratio of non-sulfated versus sulfated glycans, we have successfully adapted the well-established GC-MS linkage analysis method of partially methylated alditol acetate (PMAA) to targeted LC-MS/MS analysis in positive ion mode and quantified the ratio among non-sulfated, mono-sulfated, and di-sulfated glycans in bovine thyroglobulin as 82:13:8. In conclusion, by the newly developed nanoLC-MS/MS strategies, we can now obtain more qualitative and quantitative information of the sulfated glycome at higher sensitivity, which would be important in understanding their functional expression and physiological relevance in biological systems.
並列關鍵字
sulfoglycomics參考文獻
Angata, T., Hingorani, R., Varki, N.M., and Varki, A. (2001). Cloning and characterization of a novel mouse Siglec, mSiglec-F: differential evolution of the mouse and human (CD33) Siglec-3-related gene clusters. J Biol Chem 276, 45128-45136.
Balog, C.I., Stavenhagen, K., Fung, W.L., Koeleman, C.A., McDonnell, L.A., Verhoeven, A., Mesker, W.E., Tollenaar, R.A., Deelder, A.M., and Wuhrer, M. (2012). N-glycosylation of colorectal cancer tissues: a liquid chromatography and mass spectrometry-based investigation. Mol Cell Proteomics 11, 571-585.
Bistrup, A., Bhakta, S., Lee, J.K., Belov, Y.Y., Gunn, M.D., Zuo, F.R., Huang, C.C., Kannagi, R., Rosen, S.D., and Hemmerich, S. (1999). Sulfotransferases of two specificities function in the reconstitution of high endothelial cell ligands for L-selectin. J Cell Biol 145, 899-910.
Bochner, B.S. (2009). Siglec-8 on human eosinophils and mast cells, and Siglec-F on murine eosinophils, are functionally related inhibitory receptors. Clin Exp Allergy 39, 317-324.
Bochner, B.S., Alvarez, R.A., Mehta, P., Bovin, N.V., Blixt, O., White, J.R., and Schnaar, R.L. (2005). Glycan array screening reveals a candidate ligand for Siglec-8. J Biol Chem 280, 4307-4312.