title: Detailed O-glycomics of the Muc2 mucin from colon of wild-type, core 1- and core 3-transferase-deficient mice highlights differences compared with human MUC2.
abstract: The heavily O-glycosylated mucin MUC2 constitutes the major protein in the mucosal layer that acts as a physical barrier protecting the epithelial layer in the colon. In this study, Muc2 was purified from mucosal scrapings from the colon of wild-type (WT) mice, core 3 transferase knockout (C3Gnt(-/-)) mice and intestinal epithelial cell-specific core 1 knockout (IEC C1Galt1(-/-)) mice. The Muc2 O-glycans were released by reductive β-elimination and analyzed with liquid chromatography-mass spectrometry in the negative-ion mode. Muc2 from the distal colon of WT and C3Gnt(-/-) knockout mice carried a mixture of core 1- or core 2-type glycans, whereas Muc2 from IEC C1Galt1(-/-) mice carried highly sialylated core 3- and core 4-type glycans. A large portion of NeuAc in all mouse models was positioned on disialylated N-acetyllactosamine units, an epitope not reported on human colonic MUC2. Mass spectra and proton NMR spectroscopy revealed an abundant NeuAc linked to internally positioned N-acetylglucosamine on colonic murine Muc2, which also differs markedly from human MUC2. Our results highlight that murine colonic Muc2 O-glycosylation is substantially different from human MUC2, which could be one explanation for the different commensal microbiota of these two species.
authors.affiliation: Department of Medical Biochemistry, University of Gothenburg, PO Box 440, 405 30 Gothenburg, Sweden. kristina.thomsson@medkem.gu.se
authors.forename: Kristina A
authors.initials: KA
authors.lastname: Thomsson
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Holmén-Larsson
authors.forename: Jonas
authors.initials: J
authors.lastname: Angström
authors.forename: Malin Ev
authors.initials: ME
authors.lastname: Johansson
authors.forename: Lijun
authors.initials: L
authors.lastname: Xia
authors.forename: Gunnar C
authors.initials: GC
authors.lastname: Hansson
mesh_terms: D000606:Amino Sugars / Q000378:metabolism*; D000818:Animals; D002240:Carbohydrate Sequence; D002853:Chromatography, Liquid; D003106:Colon / Q000378:metabolism*; D000939:Epitopes; D005700:Galactosyltransferases / Q000502:physiology*; D054794:Glycomics; D006031:Glycosylation; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D009682:Magnetic Resonance Spectroscopy; D054892:Metagenome; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D055262:Mucin-2 / Q000378:metabolism*; D017351:N-Acetylglucosaminyltransferases / Q000502:physiology*; D011134:Polysaccharides / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000606:Amino Sugars; D000939:Epitopes; C524625:MUC2 protein, human; C524626:Muc2 protein, mouse; D055262:Mucin-2; D011134:Polysaccharides; C000458:N-acetyllactosamine; C515597:C1galt1 protein, mouse; D005700:Galactosyltransferases; D017351:N-Acetylglucosaminyltransferases; C117361:beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-N-acetylglucosaminyltransferase 3