The studies outlined in this application will explore the structure and function of colonic glycoproteins in an effort to understand their role in inflammatory bowel disease. Past studies in this laboratory have demonstrated the presence of several structurally distinct mucin glycoproteins in the human colon, designated mucin species I-VI (HCM I-IV) which appear to arise from functionally distinct subpopulations of goblet cells. The biological importance of the glycoprotein species is supported by the demonstration of selective deficiency in one species (IV) in specific association with ulcerative colitis. The molecular and cellular basis of colonic mucin glycoprotein heterogeneity will be defined using human colonic tissue and a colon carcinoma derived cell line (HT-29, N2) which differentiates into a goblet cell population in vitro. The genes encoding the peptide backbones of the individual mucin species will be cloned utilizing nucleotide sequences derived from peptide digests and anti-HCM antibodies. These studies should provide insight into the fundamental peptide and macromolecular structure of the mucin class of glycoproteins generally. In addition regulation of biosynthesis and secretion of colonic glycoproteins will be examined and physiologic secretagogues identified through the use of in vitro organ culture and cell culture techniques. The basis of the observed defect of HCM species IV in ulcerative colitis will be delineated. Expression of HCM peptide genes in UC and control tissues will be assessed and effects of therapeutic agents on the expression of HCM species will also be examined. Additional studies will be undertaken to characterize glycoconjugate structural determinants recognized by newly developed monoclonal antibodies which specifically bind to UC mucosa. Thus, a comprehensive study of colonic glycoproteins is proposed to enhance our understanding of their structure, function and contribution to inflammatory bowel disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK034422-09
Application #
3232761
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1984-07-01
Project End
1994-06-30
Budget Start
1992-07-01
Budget End
1994-06-30
Support Year
9
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02199
Dignass, A; Lynch-Devaney, K; Kindon, H et al. (1994) Trefoil peptides promote epithelial migration through a transforming growth factor beta-independent pathway. J Clin Invest 94:376-83
Podolsky, D K; Lynch-Devaney, K; Stow, J L et al. (1993) Identification of human intestinal trefoil factor. Goblet cell-specific expression of a peptide targeted for apical secretion. J Biol Chem 268:6694-702
Targan, S R; Landers, C J; King, N W et al. (1992) Ulcerative colitis-linked antineutrophil cytoplasmic antibody in the cotton-top tamarin model of colitis. Gastroenterology 102:1493-8
Koizumi, M; King, N; Lobb, R et al. (1992) Expression of vascular adhesion molecules in inflammatory bowel disease. Gastroenterology 103:840-7
Podolsky, D K (1991) Inflammatory bowel disease (2) N Engl J Med 325:1008-16
Suemori, S; Lynch-Devaney, K; Podolsky, D K (1991) Identification and characterization of rat intestinal trefoil factor: tissue- and cell-specific member of the trefoil protein family. Proc Natl Acad Sci U S A 88:11017-21
Podolsky, D K (1991) Inflammatory bowel disease (1) N Engl J Med 325:928-37
Tysk, C; Riedesel, H; Lindberg, E et al. (1991) Colonic glycoproteins in monozygotic twins with inflammatory bowel disease. Gastroenterology 100:419-23