Exploring the interplay of mucin with biologically-relevant amorphous magnesium-calcium phosphate nanoparticles

Hypothesis: It has been recently shown that, in our organism, the secretions of Ca2+, Mg2+ and phosphate ions lead to the precipitation of amorphous magnesium-calcium phosphate nanoparticles (AMCPs) in the small intestine, where the glycoprotein mucin is one of the most abundant proteins, being the main component of the mucus hydrogel layer covering gut epithelium. Since AMCPs precipitate in vivo in a mucinrich environment, we aim at studying the effect of this glycoprotein on the formation and features of endogenous-like AMCPs. Experiments: AMCPs were synthesized from aqueous solution in the presence of different concentrations of mucin, and the obtained particles were characterised in terms of crystallinity, composition and morphology. Solid State NMR investigation was also performed in order to assess the interplay between mucin and AMCPs at a sub-nanometric level. Finding: Results show that AMCPs form in the presence of mucin and the glycoprotein is efficiently incorporated in the amorphous particles. NMR indicates the existence of interactions between AMCPs and mucin, revealing how AMCPs in mucin-hybrid nanoparticles affect the features of both proteic and oligosaccharidic portions of the glycoprotein. Considering that the primary function of mucin is the protection of the intestine from pathogens, we speculate that the nature of the interaction between AMCPs

Automated summary

The study demonstrates that AMCPs can form in the presence of mucin, with the glycoprotein efficiently incorporated in the amorphous particles. Solid State NMR investigation reveals interactions between AMCPs and mucin, affecting the features of the glycoprotein.