Abstract 19486: N-Glycosylation Changes in the Human Aortic Valve Structure During Development and Disease by Imaging Mass Spectrometry
Introduction: Changes in polysaccharide and proteoglycan distribution are a hallmark of heart valve development and disease. However, the complex carbohydrate content of the heart valve remains virtually uncharacterized at the molecular level. N-glycosylation is a post translational modification with a role in protein localization, protein-protein interactions and modulation of cell signaling. Our proteomics data on healthy & diseased human aortic valve (AV) showed significant enrichment of functions of N-glycan processing, synthesis and congenital disorders of glycosylation. At the same time, new approaches are available for detection of N-Glycans directly from tissue.
Hypothesis: Discrete N-glycans and associated signaling networks participate in normal AV development and are deregulated in congenital aortic valve stenosis
Methods: The approach uses robotic spraying of PNGase F onto formalin fixed paraffin embedded (FFPE) tissue sections of standard thickness (5-6 μm) to release N-glycans from proteins from tissue without delocalization. Imaging mass spectrometry is then used to detect the N-glycans directly from tissue, thus providing information on regulation, structural changes and histological localization.
Results: From a small but growing cohort, distinct N-glycans are spatially restricted and regulated within the human AV structure. In healthy AV, N-glycans were segregated according to AV subanatomical features. Statistical filtering by Wilcoxon Rank Sum p-value ≤1.0E-3 and area under the receiver operating curve ≥0.7 suggested expression level changes in 27% of N-glycan (30/110) when comparing between healthy AV comparing ages 0-17 years to adult. Structural motif analysis suggested that in the healthy aging valve, core fucosylation may be decreased, while N-glycan complexity increases. Specimens with aortic valve stenosis showed distinct N-glycans that were altered in regions of pathological extracellular matrix compared to age-matched healthy counterparts, with increases in tri- and tetra-antennary structures due to disease.
Conclusions: The study suggests a novel role for N-glycosylation in healthy AV aging and in AV disease, presenting new therapeutic opportunities for AV disease treatment.
Author Disclosures: P. Angel: None.
- © 2016 by American Heart Association, Inc.