gw0742 and Colitis

Peroxisome proliferator-activated receptors (PPARs) beta/delta and gamma have overlapping roles in the negative regulation of inflammatory response genes. Ligand activation of PPARgamma protects against experimental colitis in mice. PPARbeta/delta can negatively regulate inflammation and is highly expressed in the epithelial cells of the colon, therefore PPARbeta/delta may also have a role in experimental colitis. In these studies, colitis was induced by dextran sodium sulfate (DSS) treatment in wild-type and PPARbeta/delta-null mice, with and without the PPARbeta/delta specific ligand GW0742. PPARbeta/delta-null mice exhibited increased sensitivity to DSS-induced colitis, as shown by marked differences in body weight loss, colon length, colonic morphology, myeloperoxidase activity and increased expression of mRNAs encoding the inflammatory markers interferon gamma, tumor necrosis factor-alpha, and interleukin-6 compared to similarly treated wild-type mice. Interestingly, these differences were not affected by ligand activation of PPARbeta/delta in either genotype. These studies demonstrate that PPARbeta/delta expression in the colonic epithelium inhibits inflammation and protects against DSS-induced colitis through a ligand-independent mechanism.

Topics: Animals; Colitis; Colon; Dextran Sulfate; Disease Models, Animal; Disease Progression; Enterocytes; Female; Gene Expression; Interferon-gamma; Interleukin-6; Ligands; Mice; Mice, Inbred C57BL; Peroxidase; Plasma Substitutes; Polymerase Chain Reaction; PPAR delta; PPAR-beta; RNA, Messenger; Severity of Illness Index; Thiazoles; Tumor Necrosis Factor-alpha

Interleukin-10 knockout (IL-10(-/-)) mice spontaneously develop colitis characterized by T-helper cell type 1-polarized inflammation. We tested the possible therapeutic activity of the peroxisome proliferator-activated receptor alpha (PPARalpha) ligand fenofibrate, and the PPARdelta ligand GW0742, in IL-10(-/-) mice and investigated the cellular/molecular mechanisms for fenofibrate action.. The effect of fenofibrate or GW0742 on the progression of colitis in C3H.IL-10(-/-) mice was evaluated. Effects of fenofibrate on cytokine and chemokine gene expression were studied in cultured splenocytes, pathogenic T cells isolated from C3H/HeJBir mice, and HT-29 colorectal cancer cells.. Treatment of C3H.IL-10(-/-) mice with fenofibrate delayed the onset of colitis, decreased the colonic histopathology score, and decreased colonic expression of genes encoding the inflammatory cytokines interferon-gamma and interleukin (IL)-17. The target for fenofibrate, PPARalpha, was expressed in lymphocytes, macrophages, and crypt and surface epithelial cells of the colon. The mean number of lymphocytes was decreased by more than 75% in colonic sections of fenofibrate-treated as compared with control IL-10(-/-) mice, and fenofibrate repressed interferon-gamma and IL-17 expression in isolated T cells. Fenofibrate also repressed the expression of the genes encoding 3 chemokines, CXCL10, CCL2, and CCL20, and repressed CXCL10 gene promoter activity in tumor necrosis factor-alpha-treated HT-29 cells. In contrast to the beneficial effect of fenofibrate, the PPARdelta ligand GW0742 accelerated the onset of colitis in IL-10(-/-) mice.. The immunopathology observed in IL-10(-/-) mice resembles that seen in Crohn's disease. The novel therapeutic activity of fenofibrate in this mouse model suggests that it may also have activity in Crohn's disease.

Topics: Age Factors; Animals; Cell Count; Chemokine CXCL10; Chemokines, CXC; Colitis; Crohn Disease; Disease Models, Animal; Fenofibrate; Gene Expression; HT29 Cells; Humans; Hypolipidemic Agents; Interferon-gamma; Interleukin-10; Interleukin-17; Mice; Mice, Inbred C3H; Mice, Knockout; PPAR alpha; Spleen; Th1 Cells; Thiazoles