The glycocalyx is a highly complex interface between a cell and its extracellular environment. Within this intricate mixture of structural and biochemical components, Mucins, transmembrane proteins that are forced into linear bottlebrush-like conformations due to their extensive O-glycosylation, exist as the largest structural component on the cell surface, extending 100-1000s of nm into the extracellular space. These structures have been extensively studied for their molecular recognition and signaling capabilities,1 but the impact of their sheer size and hydrodynamic bulk has only recently begun to be appreciated for its importance in mediating cellular interactions with the outside world.2 Here, we present the synthesis of a mucin-like glycopolymer generated from the post polymerization glycosylation of a poly(ethylene glycol) type backbone synthesized via the anionic polymerization of epichlorohydrin.3 We attach glycans (such as glucose) that are biochemically inert in our biological system, causing the glycopolymers to adopt extended mucin-like conformations by AFM. Subsequent attachment to cellular surfaces through a hydrophobic anchor creates a “spectator glycocalyx” that mimics the physical and structural characteristics of mucins without providing native structures for biochemical interactions. To assess the impact of these structures at the cell surface, Turkey Red Blood Cells (RBC) are utilized as a simple model system. At high polymer loading, we observe altered membrane morphology and diminished structural integrity of RBCs via microscopy and SEM. We utilize lectin agglutination assays, where the presence of polymers inhibit RBC agglutination, to show that inert bulky structures can regulate interactions at the cell surface by exerting physical forces. Using flow cytometry, we show that the spectator glycocalyx reduces the kinetic and thermodynamic binding of lectins Sambucus Nigra Agglutinin and Concanavalin A to their underlying glycan receptors. Finally, the role of the spectator glycocalyx in more complex processes, such as enzymatic activity and pathogen binding, will be discussed.

Investigating the impact of spectator glycocalyx structures on molecular interactions at the cell surface

2019 Fall National Meeting

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