Mucin polymers are the gel-forming building blocks of the mucus hydrogel that covers all wet epithelia in the body, protecting them from dehydration and shear stress. Mucins assume largely extended, threadlike conformations and are densely glycosylated. When exposed to synthetic surfaces, mucins spontaneously absorb to form highly hydrated and lubricating coatings. The mechanisms that mediate hydration and lubrication are not well understood but could provide important guidance to the treatment of patients, which secrete compromised or insufficient amounts of mucins. Here, we analyzed native and deglycosylated mucins coatings for their hydration capacity using quartz crystal microbalance and ellipsometry. Moreover, we analyzed the lubricative potential of native and deglycosylated mucin coatings by tribology. Our data show that the removal of mucin-bound glycans form the mucin resulted in a 3.5 fold decrease in hydration and a 2 order of magnitude increase in friction coefficient. These findings indicate that mucin-associated glycans are essential to achieve both hydration and lubricating by the mucins. Building on these observations, we tested if the properties of deglycosylated mucins could be restored by grafting polyethylene glycol (PEG) molecules via conjugated lectin domains. Our data indicate that the lectin-PEG conjugates can restore the hydration of the deglycosylated mucin coatings and significantly improve its lubricating properties. This observation suggests a conceptual treatment strategy where mucosal surfaces with defective hydration and lubrication properties may be partially improved by topical addition of highly hydrating molecules such as PEG, specifically targeted to the mucins.

Modulating mucin coating hydration and lubrication by de-glycosylation and polyethylene glycol binding

247th National Meeting (2014)

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