Glycan Imaging in Intact Rat Hearts and Glycoproteomic Analysis Reveal the Upregulation of Sialylation during Cardiac Hypertrophy

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• 作者：Jie Rong ; Jing Han ; Lu Dong ; Yanhong Tan ; Huaqian Yang ; Lianshun Feng ; Qi-Wei Wang ; Rong Meng ; Jing Zhao ; Shi-Qiang Wang ; Xing Chen
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：December 17, 2014
• 年：2014
• 卷：136
• 期：50
• 页码：17468-17476
• 全文大小：514K
• ISSN：1520-5126

文摘

In the heart, glycosylation is involved in a variety of physiological and pathological processes. Cardiac glycosylation is dynamically regulated, which remains challenging to monitor in vivo. Here we describe a chemical approach for analyzing the dynamic cardiac glycome by metabolically labeling the cardiac glycans with azidosugars in living rats. The azides, serving as a chemical reporter, are chemoselectively conjugated with fluorophores using copper-free click chemistry for glycan imaging; derivatizing azides with affinity tags allows enrichment and proteomic identification of glycosylated cardiac proteins. We demonstrated this methodology by visualization of the cardiac sialylated glycans in intact hearts and identification of more than 200 cardiac proteins modified with sialic acids. We further applied this methodology to investigate the sialylation in hypertrophic hearts. The imaging results revealed an increase of sialic acid biosynthesis upon the induction of cardiac hypertrophy. Quantitative proteomic analysis identified multiple sialylated proteins including neural cell adhesion molecule 1, T-kininogens, and 伪₂-macroglobulin that were upregulated during hypertrophy. The methodology may be further extended to other types of glycosylation, as exemplified by the mucin-type O-linked glycosylation. Our results highlight the applications of metabolic glycan labeling coupled with bioorthogonal chemistry in probing the biosynthesis and function of cardiac glycome during pathophysiological responses.