Ulcerative Colitis (UC) and Crohn's Disease (CD) are chronic, relapsing inflammatory disorders of the gastrointestinal tract, collectively known as Inflammatory Bowel Disease (IBD). The cause of IBD, which in U.S. affects an estimated 1 million individuals, including children and adolescents, remains largely unknown. Pathogenesis of IBD is most commonly viewed as an effect of an aberrant immune response against ubiquitous, non-pathogenic microbial antigens. In view of traditional and novel treatments of IBD, their side effects and high cost prompt investigations into new, alternative treatment modalities. One such alternative is a long-known anti-inflammatory and chemopreventive component of turmeric spice, curcumin, which was only recently reported to significantly attenuate or ameliorate experimentally induced colitis in mice. Curcumin is poorly absorbed, and extensively metabolized in the gastrointestinal tract, which may account for the reported lack of toxicity. The goal of this proposed project is to investigate the mechanism of curcumin's protective action against colitis in further detail and to provide a sufficient scientific background for clinical trials in both pediatric and adult IBD patients. This will be accomplished by studying the effectiveness of dietary curcumin in immune-based mouse models of colitis. IL-10-/- and TCRalpha-/- mice with different propensities for immune dysregulation (Th1- and Th2-dominated, respectively) will be used. Macroscopic, morphological, and biochemical evaluation will be followed by comparative genome-wide microarray analyses of gene expression profiles in colonic epithelial and immune cells in order to gain further insight into molecular targets of curcumin and its mechanism of action. Also, epithelial metabolism of curcumin will be qualitatively and quantitatively analyzed in colonocytes isolated from control mice and from mice with established differentially polarized inflammation with the help of HPLC/LC-MS technology. The compounds identified as novel metabolites of curcumin will be evaluated for anti-inflammatory activity utilizing established models of mouse macrophages (RAW264.7) and colonocytes (YAMC cells). To shed more light into novel mechanisms of curcumin action in the intestine, its effects on expression of colonic antibacterial cryptdin -related peptides will be investigated. Also, we will describe its mechanism of action on identified uniquely regulated genes such as LPS-mediated early induction of MIP-2 (murine homologue of IL-8) gene transcription. In summary, the proposed project will provide novel information about the mechanism of curcumin's action in IBD, about its molecular targets in differently polarized T-cell mediated inflammation as well as about the molecular forms of the active compound in the healthy and inflamed colon. ? ? ?
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