Project description:Background: MicroRNAs (miRNAs) acting as negative regulators of gene expression are differentially expressed in intestinal tissues of patients with inflammatory bowel disease (IBD). Assessing the functional role of miRNAs in murine models of colitis facilitates elucidating the role of specific miRNAs in human IBD. The aim of this study was to determine the miRNA signature of murine models of colitis and to assess the influence of miR-21 on intestinal inflammation. Methods: miRNAs expression was accessed by microarray for acute and chronic murine model of colitis induced by DSS or TNBS. miR-21-deficient mouse and littermates controls were assessed in the standard DSS, TNBS and CD4+ T cell transfer models of colitis. RNAs of mouse colon and CD4+CD45RBHigh cells were analyzed by miRNA and mRNA microarray, and quantitative RT-PCR. Th1 polarization was accessed by flow-cytometry and ELISA. Results: Alterations of in miRNAs expression were identified for acute and chronic DSS colitis and TNBS colitis, receptively. The Expression of miRs-21, -142-3p and -223 was were distinct between DSS and TNBS models while overlap of numerous miRNAs was seen. Importantly, miRs-19b, -192 and -215, that are decreased in IBD, were significantly decreased in all 4 models of colitis. miR-21, which is increased in IBD, was increased in TNBS colitis but not the DSS colitis models. Further assessment of the miR-21-deficient 1-/- mice revealed that the deletion of miR-21 results in the exacerbation of both the TNBS and T cell-transfer models of colitis. Conclusions: miRNAs are differentially expressed in both human IBD and murine colitis, with overlap of several IBD-associated miRNAs. The demonstration that miR-21 deletion exacerbated CD4+ T cell-mediated models of colitis provides further evidence that miRNAs play significant roles in the pathogenesis of IBD. miRNAs expression was accesed for acute and chronic murine model of colitis induced by DSS or TNBS.Total of 20 samples with duplicates were analyed in this study.

Project description:To test the efficacy of TNFR-Fc and anti-TWEAK mAb treatment alone and in combination Tumor necrosis factor (TNF)-alpha is a major effector in various inflammatory conditions. TNF-like weak inducer of apoptosis (TWEAK) is a member of the TNF superfamily that promotes inflammatory tissue damage through its receptor, FGF-inducible molecule 14 (Fn14). Since both TWEAK and TNF-alpha have been shown to mediate pathological responses through inter-dependent or independent pathways by in vitro, the potential interplay of these pathways was investigated in a mouse colitis model. Acute colitis was induced by rectal injection of trinitrobenzene sulfonic acid (TNBS), with administration of control IgG, TNF receptor (TNFR)-Ig chimeric protein, anti-TWEAK monoclonal antibody, or the combination of TNFR-Ig and anti-TWEAK antibody. On day 4, disease severity was evaluated and gene expression profiling was analyzed using whole colon tissue. Levels of transcript of TWEAK, Fn14 and NF-kB-related molecules were measured in purified colon epithelial cells (ECs). NF-kB activation was investigated with Western blot and immunohistochemical analysis. As a result, activation of the canonical, but not noncanonical NF-kB pathway was the hallmark of inflammatory responses in this model. Inflammation induced upregulation of Fn14 only in ECs but not in other cell types. Combination treatment of TNFR-Ig and anti-TWEAK antibody synergistically reduced disease severity in comparison with the control antibody or single agent treatment. Gene expression profile of the colon indicated downregulation of canonical NF-kB pathway with combination treatment. In conclusion, synergistic activation of canonical NF-kB by TWEAK and TNF-alpha is critical for the induction of inflammatory tissue damage in acute inflammation. TNBS colitis was induced by intrarectal administration of a 2 % solution of TNBS in phosphate-buffered saline (PBS): ethanol (1:1). For acute inflammatory responses, 70 M-NM-<g/g body weight of TNBS was given on day 0 and animals sacrificed on day 4. One hour prior to administration of TNBS, groups of mice were injected i.p. with the control IgG2a mAb (anti-human CD20) (10 mg/kg), TNFR-Ig (0.3 mg/kg), anti-TWEAK (mP2D10, 10 mg/kg), the combination of TNFR-Fc (0.3 mg/kg) and anti-TWEAK mP2D10 (10 mg/kg), or were untreated. For single agent and combination treatments groups, 0.3 mg/kg TNFR-Ig was employed, since 1 mg/kg of TNFR-Ig markedly ameliorated TNBS colitis but 0.3 mg/kg was much less effective as monitored by the effect on colon length and body weight. Colon tissue was rolled and snap-frozen in liquid nitrogen. Specimens for RNA extraction were cut from the frozen rolled colon. A set of experiments using 5-8 mice for each experimental group was performed twice, labelled 7 and 10 in the CEL files. Total number of mice for each experimental condition was as follows; untreated TNBS colitis group, 8; control antibody, 15; TNFR-Ig, 12; anti-TWEAK mAb, 14; combination of TNFR-Ig and anti-TWEAK mAb, 15.

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