Mucus glycoproteins from pig gastric mucosa: identification of different mucin populations from the surface epithelium

Abstract

Pig gastric mucins were isolated from the surface epithelium of the cardiac region, corpus and antrum using density-gradient centrifugation after extraction in 6 M guanidinium chloride. In CsCl/0.5 M guanidinium chloride, mucins solubilized from the cardiac region appeared as a broad unimodal band at 1.52 g/ml whereas those from the corpus and antrum occurred as high- and low-density populations at 1.50 and 1.45 g/ml respectively. High-iron diamine reacted more strongly with the cardiac mucins and the high-density populations from corpus and antrum than with the two low-density ones. In keeping with this, approx. 60% of the oligosaccharides from the former mucins and 20% from the latter contained sulphate. All surface epithelial cells of the cardiac region stained with high-iron diamine, whereas in the corpus only the epithelium in the bottom of the pits reacted, suggesting that the high-density population from this region originates from these cells. Mucins from all regions were composed of subunits, each containing highly glycosylated domains. The mucins from the cardiac region were larger than those from the corpus and antrum, and reduced subunits as well as high-molecular-mass glycopeptides from the cardiac mucins were larger than the corresponding fragments from the other regions. Ion-exchange HPLC showed that reduced subunits from the cardiac mucins and the high-density populations from the corpus and antrum were more ‘acidic’ than reduced subunits from the two low-density ones. All mucins contained a ‘neutral’ fraction, in particular those from the antrum. Pig gastric mucus thus contains a number of distinctly different mucin populations varying in buoyant density, size, ‘acidity’, glycosylation, sulphation and tissue origin.

Desulfurization of mucin by Pseudomonas aeruginosa: influence of sulfate in the lungs of cystic fibrosis patients

“…The bound sulfate level in PGM is approximately fourfold lower than that for MUC5B ( Fig. 1) but the macromolecular composition of commercial PGM has not been defined and there are considerable differences in size, density, glycosylation and sulfation of mucin preparations isolated from different areas of the pig gastric mucosa (Nordman et al, 1997). Commercial preparations are, therefore, likely to be heterogeneous mixtures and may contain not only sulfated mucin but also other sulfated glycoconjugates.…”

Atomic force microscopy of gastric mucin and chitosan mucoadhesive systems

“…This attraction has been attributed to a charge interaction between the positive amino groups and the sialic acid or sulphate residues on the mucosal glycoproteins. Structural studies have indicated that the negative charge on PGM is thought to be attributed mostly to the amount of sulphated O-linked oligosaccharide residues in the glycosylated region and not to the amount of sialic acid present [22].…”

Modulating Mucin Hydration and Lubrication by Deglycosylation and Polyethylene Glycol Binding

“…SNA binds sialic acid residues, [ 44 ] which are rare in the pig gastric mucin used for this study. [ 45 ] As a consequence, SNA binding to mucin is weak ( Figure S7, Supporting Information), and there was no signifi cant impact of SNA-PEG on hydration ( p = 0.151), confi rming that binding of the PEG to the pApoMucin coating is necessary to restore hydration. If the hydration state of deglycosylated mucins can be brought back to that of intact mucins, then the lubricating abilities of those "repaired mucins" might also approximate those of fully glycosylated mucins.…”

“…The protein solutions were pumped to fi ll the reservoir above the crystal surface, and then the fl ow was stopped to allow the coating to form. The crystal vibration was followed at its fundamental frequency (5 MHz) and six overtones (15,25,35,45,55, and 65 MHz). Changes in the resonance frequencies and in dissipation of the vibration once the excitation was stopped were followed at the seven frequencies.…”