The intestinal epithelium is sustained by a highly dynamic balance of cell proliferation, differentiation and senescence. Coordination of these processes is essential to functional and anatomic integrity. The overall goal of the studies described in this proposal is the delineation of the role of peptide growth factors in modulating proliferation and differentiation of intestinal epithelial cells at a molecular level. A major thrust of these efforts will be the examination of the regulation of expression of transforming growth factors alpha and beta (TGF alpha and beta) by intestinal epithelial cells and their role in effecting interactions between these cell populations and their extracellular matrix. Toward this goal the molecular basis of TGF regulation of a model cell surface receptor designated EGP which is involved in cell-matrix adherence will be defined through transient transfection assays in established intestinal epithelial cell lines. These studies will serve as a paradigm to understand the role of the cell surface receptors and cell matrix components in growth modulation by these peptide growth factors. In addition to a detailed examination of the role of previously recognized peptide growth factors, important goals will be the molecular characterization of two novel and biologically complementary proteins with potent growth regulating activity which are expressed by intestinal epithelial cells: MER-TGF, a protein first purified from malignant effusion which has been found by cDNA cloning to have homology to the proto-oncogene wnt-1, and TGIF, a protein which inhibits anchorage independent growth of colon-carcinoma derived cell lines and appears to have significant homology to the c-fms proto-oncogene encoding the receptor for CSF-1, a protein regulating hematopoietic stem cells. Efforts will be directed to the completion of molecular cloning of these factors as well as biochemical and biological characterization of the encoded transcripts. Regulatory elements will be defined in parallel with characterization of their effects on established intestinal epithelial cell lines and primary enterocytes. The inter-relationship between both expression and cellular response to these factors and the ubiquitous TGFs will be delineated. The relevance of the spectrum of peptide growth factors identified and characterized in a number of intestinal epithelial cell lines will be explored in the intact intestinal mucosa. The importance of this integrated network in sustaining mucosal integrity will be defined through an in vitro model of epithelial wounding as well as in vivo models of mucosal injury in the intact animal. In aggregate, these studies will provide insight into the spectrum of factors and the mechanisms which play a role in maintaining mucosal epithelial homeostasis. These insights are intrinsic to understanding injury and healing in inflammatory bowel disease and other diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK041557-04A2
Application #
3242349
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1988-09-01
Project End
1997-06-30
Budget Start
1992-07-15
Budget End
1993-06-30
Support Year
4
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02199
Cario, E; Gerken, G; Podolsky, D K (2007) Toll-like receptor 2 controls mucosal inflammation by regulating epithelial barrier function. Gastroenterology 132:1359-74
Hisamatsu, Tadakazu; Suzuki, Manabu; Podolsky, Daniel K (2003) Interferon-gamma augments CARD4/NOD1 gene and protein expression through interferon regulatory factor-1 in intestinal epithelial cells. J Biol Chem 278:32962-8
Beck, Paul L; Rosenberg, Ian M; Xavier, Ramnik J et al. (2003) Transforming growth factor-beta mediates intestinal healing and susceptibility to injury in vitro and in vivo through epithelial cells. Am J Pathol 162:597-608
Cario, Elke; Brown, Dennis; McKee, Mary et al. (2002) Commensal-associated molecular patterns induce selective toll-like receptor-trafficking from apical membrane to cytoplasmic compartments in polarized intestinal epithelium. Am J Pathol 160:165-73
Cario, E; Gerken, G; Podolsky, D K (2002) ""For whom the bell tolls!"" -- innate defense mechanisms and survival strategies of the intestinal epithelium against lumenal pathogens. Z Gastroenterol 40:983-90
Goke, M N; Cook, J R; Kunert, K S et al. (2001) Trefoil peptides promote restitution of wounded corneal epithelial cells. Exp Cell Res 264:337-44
Nishiyama, R; Sakaguchi, T; Kinugasa, T et al. (2001) Interleukin-2 receptor beta subunit-dependent and -independent regulation of intestinal epithelial tight junctions. J Biol Chem 276:35571-80
Cario, E; Podolsky, D K (2000) Differential alteration in intestinal epithelial cell expression of toll-like receptor 3 (TLR3) and TLR4 in inflammatory bowel disease. Infect Immun 68:7010-7
Podolsky, D K (2000) Review article: healing after inflammatory injury--coordination of a regulatory peptide network. Aliment Pharmacol Ther 14 Suppl 1:87-93
Cario, E; Rosenberg, I M; Brandwein, S L et al. (2000) Lipopolysaccharide activates distinct signaling pathways in intestinal epithelial cell lines expressing Toll-like receptors. J Immunol 164:966-72

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