Quantitative Assessment of Sialo‐Glycoproteins and N‐Glycans during Cardiomyogenic Differentiation of Human Induced Pluripotent Stem Cells

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) may be used in regenerative medicine for individualized tissue transplants in future. For application in patients, the generated CMs have to be highly pure and well characterized. To overcome the prevalent scarcity of CM-specific markers, we quantitatively assessed cell surface exposed sialo-glycoproteins and N-glycans of hiPSCs, CM progenitors and CMs derived thereof. Applying a combination of metabolic labeling and specific sialo-glycoprotein capture, we could highly enrich and quantify membrane proteins during cardiomyogenic differentiation. Among them we identified a number of novel, putative biomarkers for hiPSC-CMs. Analysis of the N-glycome by capillary gel electrophoresis revealed three novel structures comprising 1,3-linked galactose, 2,6-linked sialic acid and complex fucosylation that were highly specific for hiPSCs. Bisecting GlcNAc structures strongly increased during differentiation and we propose that they are a characteristic feature of early, immature CMs.