A cultured epithelial cell line which retains specific electrolyte transport functions may serve as a model system to study those functions. Culture cells allow the transport processes to be studied in a homogeneous group of cells free of the confounding effect of other cell types. This is an advantaje which should allow better and more specific identification of the sequence of cellular events involved in a transport phenomenon, beginning with receptor binding to activation of intracellular amplifying mechanisms to stimulation of various transport pathways on the plasma membrane. Initial characterization of receptor-mediated ion transport properties in the T84 colonic cell line, an established human epithelial cell line, suggests that this cell line may serve as a useful secretory model system. In this proposal, the role of Cl- and K+ channels and Na+,K+,Cl- cotransport in cAMP and Ca++ mediated secretion will be further investigated in T84 cells. Initial studies suggest that these transport pathways are intimately involved in secretory mechanisms. Three methods will be used to study ion transport. 1) The Ussing chamber, to study transepithelial movement of ions. Synergism between cAMP and Ca++ mediated secretion will be tested, and the involvement of transport pathways and intracellular mediators in secretory processes will be studied. 2) Radionuclide uptake and efflux in whole cells to directly verify the specific transport pathways involved and to study their interactions. 3) Transport studies in purified brush border and basolateral membranes to localize transport pathways and determine its transport characteristics. The proposed studies should allow us to identify various transport pathways on the plasma membrane involved in the secretory events and provide information about the intracellular amplifying mechanisms. Information on the inhibition of transport pathways and the interruption of intracellular amplifying mechanisms should provide a rational approach to the development of antidiarrheal medications.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK028305-05
Application #
3228720
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1981-07-01
Project End
1989-03-31
Budget Start
1986-04-01
Budget End
1987-03-31
Support Year
5
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Type
Schools of Medicine
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Barrett, Kim E; McCole, Declan F (2016) Hydrogen peroxide scavenger, catalase, alleviates ion transport dysfunction in murine colitis. Clin Exp Pharmacol Physiol 43:1097-1106
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McCole, D F; Barrett, K E (2009) Decoding epithelial signals: critical role for the epidermal growth factor receptor in controlling intestinal transport function. Acta Physiol (Oxf) 195:149-59
Scharl, Michael; Paul, Gisela; Weber, Achim et al. (2009) Protection of epithelial barrier function by the Crohn's disease associated gene protein tyrosine phosphatase n2. Gastroenterology 137:2030-2040.e5
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Tillinger, Wolfgang; McCole, Declan F; Keely, Stephen J et al. (2008) Hypertonic saline reduces neutrophil-epithelial interactions in vitro and gut tissue damage in a mouse model of colitis. Am J Physiol Regul Integr Comp Physiol 295:R1839-45
McCole, Declan F; Barrett, Kim E (2007) Varied role of the gut epithelium in mucosal homeostasis. Curr Opin Gastroenterol 23:647-54
McCole, Declan F; Truong, Anh; Bunz, Michael et al. (2007) Consequences of direct versus indirect activation of epidermal growth factor receptor in intestinal epithelial cells are dictated by protein-tyrosine phosphatase 1B. J Biol Chem 282:13303-15
Keely, Stephen J; Scharl, Michael M; Bertelsen, Lone S et al. (2007) Bile acid-induced secretion in polarized monolayers of T84 colonic epithelial cells: Structure-activity relationships. Am J Physiol Gastrointest Liver Physiol 292:G290-7
Chow, Jimmy Y C; Barrett, Kim E (2007) Role of protein phosphatase 2A in calcium-dependent chloride secretion by human colonic epithelial cells. Am J Physiol Cell Physiol 292:C452-9

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