Human intestinal mucus proteins isolated by transanal irrigation and proctosigmoidoscopy

Abstract

Human intestinal mucus essentially consists of a network of Mucin2 glycoproteins embedded in many lower molecularweight proteins. This paper contributes to the proteomic study of human intestinal mucus by comparing two sample collectionmethods (transanal irrigation and brush cytology during proctosigmoidoscopy) and analysis techniques (electrophoresis anddigestion in solution). The entire sample collection and treatment process is explained, including protein extraction, digestion anddesalination and peptide characterisation using a nanoAcquity UPLC chromatograph coupled to an HDMS spectrometer equipped with a nanoESI source. Collecting mucus via transanal irrigation provided a larger sample volume and protein concentration from a single patient. The proctosigmoidoscopy sample could be analysed via digestion in solution after depleting albumin. The analysisindicates that a simple mucus lysis method can evaluate the electrophoresis and digestion in solution techniques. Studying human intestinal mucus complexes is important because they perform two essential survival functions for humans as the first biochemical and physical defences for the gastrointestinal tract and a habitat for intestinal microbiota, which are primarily hosted in the colon and exceeds the human genetic information and cell number 100- and 10-fold (1).

Human intestinal mucus essentially consistsof a network of Mucin2 glycoproteinsembedded in many lower molecularweight proteins. This paper contributes tothe proteomic study of human intestinalmucus by comparing two sample collectionmethods (transanal irrigation and brushcytology during proctosigmoidoscopy) andanalysis techniques (electrophoresis anddigestion in solution). The entire samplecollection and treatment process is explained,including protein extraction, digestion anddesalination and peptide characterisationusing a nanoAcquity UPLC chromatographcoupled to an HDMS spectrometer equippedwith a nanoESI source. Collecting mucus viatransanal irrigation provided a larger samplevolume and protein concentration from asingle patient. The proctosigmoidoscopysample could be analysed via digestion insolution after depleting albumin. The analysisindicates that a simple mucus lysis methodcan evaluate the electrophoresis and digestionin solution techniques. Studying humanintestinal mucus complexes is importantbecause they perform two essential survivalfunctions for humans as the first biochemicaland physical defences for the gastrointestinaltract and a habitat for intestinal microbiota,which are primarily hosted in the colon andexceeds the human genetic information andcell number 100- and 10-fold (1).