The native glycocalyx is an ordered, self-assembled hierarchical micro- and nanoarray lamellar structure conserved in evolution

Abstract

The native ultrastructure of the glycocalyx remained unknown despite its functional importance in cellular recognition/adhesion and selective filtration. The major components of this universal extracellular coat, mucins, proteoglycans, glyconectins, and hyaluronan, share similar physicochemical properties of high molecular weight, glycan richness, and amply hydrated bottlebrush polymer morphologies with comparable intramolecular anionic charge distribution. The diversity of these glycoconjugate intermolecular binding under physiologically highly hydrated and specific ionic conditions keeps the native glycocalyx structure enabling it to function. Irrespective of the intricacy of the glycocalyx physiological milieu preservation and molecular organization, only a dehydrated non-native state presenting an artefactual unorganized fiber mesh was imaged. Using cryo-SEM after cryo-preservation with minimal sublimation to conserve water, ion distribution, and the native intermolecular interactions, we unveil well-organized lamellae of glycoconjugates self-assembled in hierarchical micro- and nanoarrays for the glycocalyx of human cell and self-assembled glyconectin glycocalyx from an evolutionary most distant sponge despite differences in sequence and composition. Our combined AFM binding strength measurements and cryo-SEM imply that evolutionarily preserved glycocalyx micro- and nano-morphologies are formed by thermodynamically driven self-assembly of glycoconjugates having similar physico-chemical properties. TeaserThe extracellular glycocalyx coat is a self-organizing ultrastructure in human and sponge cells.