Project Number: 1235-52000-053-00
Project Type: Appropriated

Start Date: Mar 28, 2004
End Date: Mar 15, 2009

Objective:
1) To identify the mechanisms of local type 1 and type 2 cytokine-dependent alterations in gut function in the colon and in unaffected areas in the small intestine. 2) Determine the impact of specific nutritional deficiencies alone (Vitamin E and Selenium) on baseline levels of cytokines and cytokine receptor expression and on gut function. 3) Determine the impact of specific nutritional deficiencies (Vitamin E and Selenium) on immune-induced alterations in gut function.

Approach:
Experiments will compare responses in Wild Type mice or mice deficient in the signaling factors Stat4 or Stat6 after treatment with agents known to elevate Th1 (inflammation using trinitrobenzene sulfonic acid) or Th2 cytokines (enteric helminth infection). Specific nutritional deficiencies that impact these responses and affect gut function will be examined; treatment groups will include 1) vehicle, 2) TNBS, 3) infection, 4) VE and Se deficient diet). Molecular (real time RT-PCR) will be used to determine diet-induced alterations in cytokine profiles and histological evaluation will be performed to identify modifications in infiltrating cells as a result of the diet deficiencies. Laser capture microscopy (LCM) will be used to localize cytokine receptors to specific cell types including epithelial mucosa, smooth muscle and nerves. Preliminary data indicate that diets deficient in both VE and Se impair the ability of the intestine to clear enteric nematodes and affect intestinal function. Function is defined as changes in epithelial cell secretion and absorption in vitro (Epithelial cell transport in Ussing chambers) and smooth muscle contraction in vitro (Isometric smooth muscle contraction). Evaluation of histological changes and assessment of cytokine and cytokine receptor expression will be determined routinely using LCM and tissue cytokines using RT-PCR.