The long term objective of this project is to determine the functional significance of structural specializations of alimentary tract mucosae in health and disease. Three areas of significance to normal intestinal mucosal function and to the mucosal response to injury will be studied. I: M cells overlying mucosal lymphoid follicles provide focal sites of permeability through which antigenic molecules and selected microorganisms can breach the epithelial barrier to initiate immune responses or infection. Molecular probes, immunocytochemical methods and morphometry will be used in in vivo and in vitro systems to determine the role of specific cytoplasmic organelles (including microtubles, microfilaments and acidic compartments) in the uptake by adsorptive endocytosis and by fluid phase endocytosis and transport of macromolecules by rabbit and rat M cells. Whether M cells simply shuttle macromolecules across their cytoplasm by vesicular transport or also sort macromolecules into prelysosomal or lysosomal pathways for processing or degradation will be examined in a quantitative fashion. II: A model of localized lectin-induced injury to rat absorptive cell microvilli which resembles injury to microvilli seen in disease (celiac-sprue, tropical sprue) will be studied to: 1) determine the pathway(s) of glycoconjugates from their sites of assembly in ER and Golgi to their incorporation into microvillus membrane in injured and undamaged absorptive cells, 2) assess the role of microtubules in the vectorial transport of membrane components across the terminal web and other cell regions and 3) define alterations in membrane structure and composition associated with microvillus injury and the restitution process. Morphometric, radioautographic and freeze-fracture methods will be used in concert with biochemical analyses of isolated microvillus membranes. III: Since the basement membrane influences expression of differentiated functions by epithelial cells, characterization of its interaction with the epithelium is directly relevant to mucosal diseases such as celiac-sprue and other non- infectious and infectious enteritides in with differentiation is impaired. Using immunocytochemical probes for basement membrane renewal to determine: 1) whether basement membrane synthesis occurs at selected sites or uniformly along the crypt- villus axis, 2) whether epithelial cells slide along or migrate in concert with the basement membrane to which they are applied and 3) which epithelial and/or mesenchymal cells synthesize basement membrane components.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37DK036835-08
Application #
3483712
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1985-09-01
Project End
1993-08-31
Budget Start
1992-09-01
Budget End
1993-08-31
Support Year
8
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
071723621
City
Boston
State
MA
Country
United States
Zip Code
02115
Allan, C H; Mendrick, D L; Trier, J S (1993) Rat intestinal M cells contain acidic endosomal-lysosomal compartments and express class II major histocompatibility complex determinants. Gastroenterology 104:698-708
Ouellette, A J; Frederick, D; Hagen, S J et al. (1991) Class II antigen-associated invariant chain mRNA in mouse small intestine. Biochem Biophys Res Commun 179:1642-8
Trier, J S (1991) Structure and function of intestinal M cells. Gastroenterol Clin North Am 20:531-47
Blumberg, R S; Terhorst, C; Bleicher, P et al. (1991) Expression of a nonpolymorphic MHC class I-like molecule, CD1D, by human intestinal epithelial cells. J Immunol 147:2518-24
Allan, C H; Trier, J S (1991) Structure and permeability differ in subepithelial villus and Peyer's patch follicle capillaries. Gastroenterology 100:1172-9
Hagen, S J (1990) Lowicryl embedding of gastrointestinal tissues. J Electron Microsc Tech 16:37-44
Trier, J S; Allan, C H; Abrahamson, D R et al. (1990) Epithelial basement membrane of mouse jejunum. Evidence for laminin turnover along the entire crypt-villus axis. J Clin Invest 86:87-95
Bass, D M; Bodkin, D; Dambrauskas, R et al. (1990) Intraluminal proteolytic activation plays an important role in replication of type 1 reovirus in the intestines of neonatal mice. J Virol 64:1830-3
Weinman, M D; Allan, C H; Trier, J S et al. (1989) Repair of microvilli in the rat small intestine after damage with lectins contained in the red kidney bean. Gastroenterology 97:1193-204
Hagen, S J; Trier, J S (1988) Immunocytochemical localization of actin in epithelial cells of rat small intestine by light and electron microscopy. J Histochem Cytochem 36:717-27

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