Abstract MP143: Harnessing Glycomics to Understand Cardiac Biology and Disease

Cell surface glycoproteins play critical roles in maintaining cardiac structure and function, and the glycan-moiety attached to a protein is critical for proper protein folding, stability, and signaling. Despite mounting evidence that glycan structures are key modulators of heart function and must be considered when developing cardiac biomarkers, we currently do not have a comprehensive view of the glycans present in the normal human heart. Here, we used an innovative mass spectrometry approach to generate the first glycan structure libraries for primary human heart tissue, cardiomyocytes (CM) enriched from human heart tissue, and human induced pluripotent stem cell derived CM (hiPSC-CM), containing >260 N- and O- glycans. Comparing the glycome of CM enriched from primary heart tissue to that of heart tissue homogenate, 21 structures significantly differed, and the high mannose class is increased in enriched CM. Moreover, >30% of the glycome significantly changed across 20-100 days of in vitro differentiation, and only 23% of the N -glycan structures were shared between hiPSC-CM and primary CM. Overall, these observations are an important complement to genomic, transcriptomic, and proteomic profiling and reveal new considerations for the use and interpretation of hiPSC-CM models for studies of human development, disease, and drug testing. These data are also expected to aid in the evaluation of the immunogenic potential of hiPSC-CM for transplantation. Finally, harnessing differences observed between immature, proliferative hiPSC-CM and adult primary CM may be exploited to drive in vitro differentiation towards a more mature phenotype. Building on these data, current efforts are underway to develop chamber- and cell-type specific views ( e.g. cardiomyocytes, fibroblasts) of the glycome in the healthy and failing human heart. Such analyses provide a key link to understand the role glycosylation plays in cell-type specific functions and cardiac disease. The structural differences observed here, either among cell types or stages of differentiation, require complex regulation of multiple enzymes in the biosynthetic pathway, and therefore would be challenging to measure with antibody arrays, RNAseq, or proteomics. Therefore, continued application of structure-based glycomics approaches, such as the method used here, will be essential for elucidating the roles that glycans and glycoproteins play during developmental and disease processes in the human heart.