Background:: The MUC2 mucin organizes the two mucus layers in the colon. This mucin carries a large number of O‐glycans that are assumed to be attachment sites for the commensal flora found in the outer mucus layer.
Methods:: Single biopsies from the sigmoid colon of controls (25) and patients with inactive (13) or active (15) ulcerative colitis (UC) were collected during routine colonoscopy. The insoluble MUC2 mucin was prepared and separated by gel electrophoresis, its relative amount estimated, its O‐glycans released, and glycans analyzed by novel sensitive glycomics chromatography / mass spectrometry providing information on glycan structures and relative abundances. The glycosylation pattern was related to the degree of mucosal inflammation and clinical severity of the disease.
Results:: The relative abundance of MUC2 showed high individual variability. Two major glycan profiles were found; a normal pattern in the control and inactive UC patients and an aberrant profile in patients with active colitis with an increase in a subset of the smaller glycans and a decrease of several complex glycans. The magnitude of this phenomenon was significantly related to both the degree of inflammation in the biopsies and also to some extent the severity of disease course. The aberrant profile was further shown to be reversible upon remission.
Conclusions:: In the majority of the active UC patients MUC2 mucin has an altered glycan profile as compared to inactive UC and control patients. Patients with strong alterations in the glycan pattern tended to have a more severe disease course. (Inflamm Bowel Dis 2011)
1Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden, Sahlgrens’ University Hospital, Gothenburg, Sweden
2Department of Internal Medicine, University of Gothenburg, Gothenburg, Sweden, Sahlgrens’ University Hospital, Gothenburg, Sweden
*Reprints: Dept. Medical Biochemistry, P.O. Box 440, 405 30 Gothenburg, Sweden
Additional supporting information may be found in the online version of this article.
Received 11 November 2010; Accepted 6 December 2010
Published online 2 February 2011 in Wiley Online Library (wileyonlinelibrary.com).
Funded by the Swedish Research Council (no. 7461, 5898, 21027, and 342‐2004‐4434), the Swedish Cancer Foundation, the Knut and Alice Wallenberg Foundation (KAW2007.0118), IngaBritt and Arne Lundberg Foundation, Sahlgren's University Hospital (LUA‐ALF), EU‐FP7 IBDase, Wilhelm and Martina Lundgren's Foundation, Söderbergs Stiftelser, the Swedish Foundation for Strategic Research – Innate Immunity, and the Mucosal Immunobiology and Vaccine Center (MIVAC), and by a collaborative project grant from AstraZeneca Mölndal, Sweden to the University of Gothenburg.