Using MALDI imaging mass spectrometry approaches, it is possible to effectively map the tissue distribution of N-glycans and other glycan classes. Key to the approach is the automated spraying of a molecular coating of peptide N-glycosidase F to formalin-fixed paraffin embedded tissues on slides. Especially for cancer, the approach allows the simultaneous determination and localization of specific N-glycan structural classes associated with tumor, non-tumor, inflammation and stroma regions. This workflow has been standardized and applied to hundreds of individual tissues and thousands of tissue spots on tissue microarrays. Using a solvent sprayer for enzyme application not only facilitates reproducible workflows, but also provides flexibility to spray single or multi-enzyme preparations. The enzymes are applied as a molecular coating, and require humidified chambers for digestion, thus there is minimal analyte diffusion due to lack of fluid solvent conditions. Applying combinations of sprayed glycosidases allows controlled remodeling of analyte signals from tissues. Chemical stabilization of sialic acids by amidation is feasible in tissues, allowing isomeric linkage determinations. The same workflows optimized for tissues are now being adapted to glycan profiling analysis of glycoproteins by slide-based antibody arrays. Similarly, cell lines can be grown directly on slides and processed like tissue for glycan profiling, or smeared and fixed to the slide prior to similar processing workflows. An overview of these different workflow combinations that have been evaluated will be provided for N-linked glycan analysis, and how these workflows can be expanded for analysis of glycoproteins and other glycan classes in tissue, cell and biofluid substrates.

Adapting N-glycan MALDI imaging mass spectrometry workflows to create new chemo-enzymatic glycan profiling strategies for tissues, cells, and slide arrays

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.