The central nervous system (CNS) has specialized and diverse cell populations. Identifying cell-specific molecular signatures may reveal more comprehensive information about neurological pathways and CNS complexity. Protein glycosylation is one of the most common functional post-translation modifications (PTM) in the brain. Identifying cell-type dependent glycan features help provide a better understanding of their role in brain cell intercellular interactions.
In this study, we identified plasma membrane glycan features of three mammalian brain cell lines; BV2 (microglia), U87-MG (astrocytes), and differentiated SH-SY5Y (neurons), using a multi-glycomic approach. Brain cell membrane proteins comprise several types of glycoconjugates including glycosaminoglycans (GAGs), N-Glycan, and O-Glycans. To analyze the cell-specific expression of these glycoconjugates, we present a sequential enzymatic release of different glycan features from a single PVDF protein spot followed by quantification by ZIC-HILIC-LC-FLD and PGC-LC-MS/MS. In addition to this quantitative study, we use a panel of 9 FITC conjugated lectins to microscopically visualize the glycome of the cellular surface and validate the analytical results.
Our results revealed brain cell-type specific glycan expression; for example, both SNA lectin binding and LC-MS/MS revealed the absence of α-2,6 linked sialic acid glycans on U87-MG cells and SNA and WFA lectin showed cell-type specific binding. These data highlight the potential role of protein glycosylation type as a unique tool to differentiate brain cell types. In summary, this study advances our knowledge of quantitative and qualitative cell-specific glycan features in the central nervous system