Target For Treatment Of Inflammatory Bowel Disease Research Articles

ALDH1A Inhibition Suppresses Colitis and Alters α4β7 Integrin Expression on Activated T Cells in Mdr1a-/- Mice.

There are limited pharmacological treatment options for inflammatory bowel disease (IBD), and some of these options are expensive and administered by injection or infusion. Thus, new cheaper and easier (oral) treatment options are needed. ALDH1A enzymes produce retinoic acid that can affect intestinal diseases such as IBD by regulating immune cells in the gut. We previously demonstrated that an orally deliverable ALDH1A inhibitor, WIN 18,466, can suppress colitis in an acute mouse model of IBD. Here, we tested the efficacy of ALDH1A inhibition in a chronic mouse model of IBD. Mdr1a-/- mice were treated with a diet containing WIN 18,446 starting 1 week prior to inducing colitis by H. bilis inoculation. Treatment was continued until the study end point and colitis was monitored based on clinical symptoms and confirmed by histological analysis. Immune cell phenotypes in colon-draining lymph nodes (cMLN) were analyzed. WIN 18,446 treatment reduced clinical symptoms and improved histopathologic colitis scores. This was associated with decreased expression of the gut homing integrin, α4β7, on T cells in cMLN; increased expression of CD103, a protein associated with tissue-resident memory T cells; and changes in dendritic cells, plasmacytoid dendritic cells and B cells in inhibitor-treated mice. ALDH1A inhibition broadly influences immune cells during colitis and is a potential new target for IBD treatment. Future studies will be needed to determine the efficacy of ALDH1A inhibition on active colitis and to evaluate its relative efficacy in comparison to approved drugs.

Comprehensive protocols for culturing and molecular biological analysis of IBD patient-derived colon epithelial organoids.

There are many unanswered questions regarding responses to proinflammatory signals in intestinal epithelial cells (IECs). For example, chemokines secreted by IECs upon external stimuli play multifunctional roles in both homeostasis and during inflammation. Several chemokines are upregulated during active inflammatory bowel disease (IBD), which is associated with an increased influx of immune cells into the gut mucosa. Therefore, studies on how chemokines are regulated in the intestinal epithelium may identify putative treatment targets in IBD. More recently, patient-derived ex vivo models such as intestinal organoids have facilitated molecular analysis of epithelial alterations in IBD patients own cells. Here, we describe refined experimental protocols and methods for the generation and maintenance of IBD patient-derived colonic organoids (colonoids) culture. We also give detailed description of medium, and supplements needed for colonoid establishment, growth, and differentiation, including production of Wnt-3A and Rspondin1 enriched media. Further, we present protocols for RNA and protein isolation from human colonoids, and subsequent gene expression analysis and Western blotting for e.g., signal transduction studies. We also describe how to process colonoids for chemokine protein expression analysis such as immunostaining, confocal imaging, and detection of secreted chemokines by e.g., enzyme-linked immunosorbent assay (ELISA). As proof of principle, we give examples of how the chemoattractant CCL20 can be regulated and expressed in colonoids derived from IBD-patients and healthy controls upon ligands-driven inflammation.

Fibroblasts overpressing WNT2b cause impairment of intestinal mucosal barrier

To investigate the mechanism by which fibroblasts with high WNT2b expression causes intestinal mucosa barrier disruption and promote the progression of inflammatory bowel disease (IBD). Caco-2 cells were treated with 20% fibroblast conditioned medium or co-cultured with fibroblasts highly expressing WNT2b, with the cells without treatment with the conditioned medium and cells co-cultured with wild-type fibroblasts as the control groups. The changes in barrier permeability of Caco-2 cells were assessed by measuring transmembrane resistance and Lucifer Yellow permeability. In Caco-2 cells co-cultured with WNT2b-overexpressing or control intestinal fibroblasts, nuclear entry of β-catenin was detected with immunofluorescence assay, and the expressions of tight junction proteins ZO-1 and E-cadherin were detected with Western blotting. In a C57 mouse model of dextran sulfate sodium (DSS)-induced IBD-like enteritis, the therapeutic effect of intraperitoneal injection of salinomycin (5 mg/kg, an inhibitor of WNT/β-catenin signaling pathway) was evaluated by observing the changes in intestinal inflammation and detecting the expressions of tight junction proteins. In the coculture system, WNT2b overexpression in the fibroblasts significantly promoted nuclear entry of β-catenin (P < 0.01) and decreased the expressions of tight junction proteins in Caco-2 cells; knockdown of FZD4 expression in Caco-2 cells obviously reversed this effect. In DSS-treated mice, salinomycin treatment significantly reduced intestinal inflammation and increased the expressions of tight junction proteins in the intestinal mucosa. Intestinal fibroblasts overexpressing WNT2b causes impairment of intestinal mucosal barrier function and can be a potential target for treatment of IBD.

Evolution of Treatment Targets in Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD), which encompasses Crohn's disease and ulcerative colitis, represents a chronic and progressive condition characterised by periods of active inflammation interspersed with periods of remission. The resulting disease burden, arising from patient symptoms and complications, leads to a diminished quality of life for individuals with IBD. Despite significant advancements in the management of IBD, the ideal treatment targets are uncertain. The evolution of treatment targets in IBD signifies a paradigm shift from mere symptom control to a more holistic approach that aims at achieving deeper remission and improving patients' quality of life. The “treat-to-target” paradigm, guided by international consensus and expert insights, emphasises the importance of tailoring therapeutic goals to individual patient needs and disease severity. As our understanding of IBD's underlying mechanisms deepens and therapeutic options expand, treatment goals have evolved to include not only clinical response but also the pursuit of more objective endpoints such as endoscopic healing. Emerging targets, such as the assessment of transmural healing through cross-sectional imaging and the focus on histologic remission as a predictor of long-term outcomes, hold great promise in further refining IBD management strategies. However, further research is needed to recommend these treatment targets in clinical practice. In the review we explore the ongoing evolution of treatment targets in IBD aimed at optimising patient outcomes and ultimately improving quality of life (QoL).

P002 Glial cell line-Derived Neurotrophic Factor (GDNF) improves intestinal wound healing – A new target for IBD treatment?

Abstract Background Due to the rising incidence and socioeconomic relevance of Inflammatory Bowel Disease (IBD) worldwide, new therapeutic strategies are necessary to improve patient care. Since immunosuppressants are partially insufficient with relevant rates of side effects, novel concepts of treatment need to be developed. Mucosal and/or histological healing represent potential criteria to measure disease activity and are mentioned in current guidelines as favorable prognostic factors regarding disease outcomes. In previous studies, the soluble factor Glial cell line-Derived Neurotrophic Factor (GDNF) has been shown to be significantly reduced in tissue specimens from IBD patients and to be critically involved in intestinal epithelial barrier maturation. Therefore, the goal of this study was to further analyze the potential role of GDNF in IBD. Methods Intestinal wound healing was assessed in endoscopic biopsy-based wound assays as well as dextran sodium sulphate (DSS)-induced colitis in vivo. During the experiments, C57Bl/6 mice were either injected with GDNF or sodium chloride intraperitoneal while tissue samples were used for detailed molecular analyses. Further, scratch wound assays were performed in Caco2 monolayers to identify molecular pathways and cell mechanisms in vitro. Results Intraperitoneal injection of GDNF resulted in significantly enhanced wound closure in vivo. During the DSS-induced colitis model, mice treated with GDNF demonstrated significantly improved recovery from colitis in comparison to mice injected with sodium chloride. Similarly, application of GDNF in a scratch wound assay significantly enhanced wound closure in vitro. Mechanistically, molecular analysis revealed that GDNF application resulted in significantly increased cell proliferation. The effect of GDNF on cell proliferation was based on upregulation of LGR5-positive cells with increased phosphorylation of pSrc. Further studies demonstrated that the effect of GDNF on wound healing and cell proliferation could be inhibited by application of a Src-inhibitor. Conclusion GDNF significantly improves intestinal mucosal healing in vivo and in vitro which results in significantly enhanced recovery from colitis. While this effect is driven by increased cell proliferation due to upregulation of LGR5-positive cells and increased phosphorylation of pSrc, previous studies already demonstrated the critical impact of GDNF on epithelial barrier function. Following that, GDNF might have great potential in IBD treatment and could be a new target for future therapeutic approaches.

Oral Nanoparticles of SNX10-shRNA Plasmids Ameliorate Mouse Colitis.

BackgroundOur previous study found that deletion of Sorting nexin 10 (SNX10) can protect against colonic inflammation and pathological damage induced by dextran sulfate sodium (DSS). This inspired us that modulation of SNX10 expression in colonic epithelial cells might represent a promising therapeutic strategy for inflammatory bowel disease (IBD).MethodsEffective delivery of siRNA/shRNA to silence genes is a highly sought-after means in the treatment of multiple diseases. Here, we encapsulated SNX10-shRNA plasmids (SRP) with polylactide-polyglycolide (PLGA) to make oral nanoparticles (NPs), and then applied them to acute and chronic IBD mice model, respectively. The characteristics of the nanoparticles were assayed and the effects of SRP-NPs on mouse IBD were evaluated.ResultsHigh-efficiency SNX10-shRNA plasmids were successfully constructed and coated with PLGA to obtain nanoparticles, with a particle size of 275.2 ± 11.4mm, uniform PDI distribution, entrapment efficiency of 87.6 ± 2.5%, and drug loading of 13.11 ± 1.38%, displayed dominant efficiency of SNX10 RNA interference in the colon. In both acute and chronic IBD models, SRP-NPs could effectively reduce the loss of mice body weight, relieve the intestinal mucosal damage and inflammatory infiltration, inhibit the expression of inflammatory cytokines IL-1β, IL-23, TNF-α, and down-regulate the expression of toll-like receptors (TLRs) 2 and 4.ConclusionOral nanoparticles of SNX10-shRNA plasmid displayed dominant efficiency of SNX10 RNA interference in the colon and ameliorate mouse colitis via TLR signaling pathway. SNX10 is a new target for IBD treatment and nanoparticles of SNX10-shRNA plasmid might be a promising treatment option for IBD.

Protective Effects of ALDH1A Enzyme Inhibition on Helicobacter-Induced Colitis in Smad3-/- Mice are Associated with Altered α4ß7 Integrin Expression on Activated T Cells.

Many inflammatory bowel disease (IBD) patients require surgical intervention due to limited pharmacological treatment options. Antibodies targeting α4ß7, a gut-homing integrin, are one of the most promising IBD treatments. As retinoic acid (RA) regulates expression of gut-homing proteins including α4ß7 integrin, we tested if ALDH1A enzymes in the RA synthesis pathway could be targeted for IBD treatment using a potent inhibitor, WIN 18,446. Age- and sex-matched Smad3−/− mice were fed a diet with and without WIN 18,446 for 3 weeks before triggering inflammation with Helicobacter bilis infection. Colitis was evaluated by histopathology one week following the IBD trigger, and T cell subsets were evaluated before and after the IBD trigger. WIN 18,446 treatment significantly reduced IBD severity in Smad3−/− mice and reduced expression of α4ß7 integrin on multiple activated CD4+ T cell subsets. This change was associated with increased ratios of induced regulatory T cells to Th17 cells during the inflammatory response in the draining lymph nodes. These studies indicate that RA reduction via ALDH1A enzyme inhibition is a potential new target for IBD treatment. Further studies are needed to examine its effects on other types of immune cells, to evaluate the efficacy window for this target, and to determine its efficacy in other animal models of IBD.

Current Status of M1 and M2 Macrophages Pathway as Drug Targets for Inflammatory Bowel Disease.

Chronic inflammation of the gastrointestinal system is mediated by both the immune system activity and homeostasis, mainly through releasing of various cytokines and chemokines, as well as the transmigration of the inflammatory cells to the affected site. In between, macrophages are key mediators of the immune system, nearly located all over the gastrointestinal tract. Macrophages have vital influence on the inflammatory condition with both pro-inflammatory and anti-inflammatory functions. Their polarization status has been linked to numerous metabolic disorders such as inflammatory bowel disease (IBD). The equilibrium between the phenotypes and functions of inflammatory M1 and anti-inflammatory M2 cells is regulated by both extracellular and intracellular stimuli, determining how the disease progresses. Thereby, factors that interchange such balance in the direction of increasing M2 macrophages offer unique approaches for future management of IBD. This study reflects the novel IBD treatment targets via the immune system's pathway, reporting the latest treatments that regulate the M1/M2 macrophages distribution in a way to favor IBD.

Role of microRNA-449a in the progress of inflammatory bowel disease in children

This study aimed to investigate the expression and role of microRNA-449a (miR-449a) in inflammatory bowel disease (IBD) in children, and further to explore the underlying mechanism. To study the role of miR-449a in IBD development, an in vitro inflammatory model of IBD was conducted by stimulating the normal intestinal epithelial cells Caco-2 with 2% dextran sulfate sodium (DSS). The results showed that the miR-449a level was significantly higher in children with IBD than that in children without IBD. Notch1 was a direct target gene of miR-449a. The increased levels of TNF-α, IL-1β and IL-6, reduced cell viability and enhanced cell apoptosis in Caco-2 cells caused by DSS administration were significantly inhibited by miR-449a inhibition. Besides, DSS significantly decreased the level of Notch1, Hes-1, Hey-1 and Bcl-2, and increased Bax expression, and these changes were prevented by miR-449a inhibitor. Importantly, all the effects of miR-449a inhibitor on Caco-2 cells were eliminated by Notch1 gene silencing. In conclusion, the data of our study indicated that miR-449a was up-regulated in IBD in children, and miR-449a inhibitor could inhibit inflammatory response and cell apoptosis by targeting Notch1 in IBD in vitro. The miR-449a/Notch1 axis might be a novel target for IBD treatment.

Towards improved control of inflammatory bowel disease.

Inflammatory bowel disease (IBD) is characterized by activation of both the innate and adaptive immune system in genetically susceptible individuals, resulting in chronic intestinal inflammation. The triggers that initiate and perpetuate this continuous inflammation are the subject of much speculation and research, although the central role of the intestinal microbiota is recognized, and is even a target for treatment in some circumstances. The mainstay of modern IBD treatment is suppression of the immune response towards as yet unspecified antigens, and conventional therapy includes corticosteroids, 5-aminosalicylic acid (5-ASA), thiopurines and methotrexate. Reducing activity of specific mediators has proven efficacious, including adhesion molecules, such as the gut-homing integrin α4 β7 expressed on the surface of circulating immune cells, and cytokines, such as tumour necrosis factor α (TNF-α). This has been achieved using biologic agents including monoclonal antibodies. Recent discoveries in immunology and neuroscience have revealed that signals in the peripheral nervous system regulate inflammation, including levels of TNF-α. The understanding of the mechanisms of the neuro-immune communication involved in inflammation control in the gut is evolving, but is as yet incomplete. Clinical studies using implanted vagus nerve stimulators for treatment of IBD show encouraging results. Accordingly, the neural reflex control of inflammation is emerging as a potential therapeutic target in treatment of IBD. Here, we review current therapeutic options and neural reflex control of gut immunity in the context of intestinal inflammation.

Development of a core outcome set for clinical trials in inflammatory bowel disease: study protocol for a systematic review of the literature and identification of a core outcome set using a Delphi survey

IntroductionCrohn’s disease (CD) and ulcerative colitis (UC), the main forms of inflammatory bowel disease (IBD), are chronic, progressive and disabling disorders of the gastrointestinal tract. Although data from randomised controlled...

Deoxycholic Acid Triggers NLRP3 Inflammasome Activation and Aggravates DSS-Induced Colitis in Mice.

A westernized high-fat diet (HFD) is associated with the development of inflammatory bowel disease (IBD). High-level fecal deoxycholic acid (DCA) caused by HFD contributes to the colonic inflammatory injury of IBD; however, the mechanism concerning the initiation of inflammatory response by DCA remains unclear. In this study, we sought to investigate the role and mechanism of DCA in the induction of inflammation via promoting NLRP3 inflammasome activation. Here, we, for the first time, showed that DCA dose-dependently induced NLRP3 inflammasome activation and highly pro-inflammatory cytokine-IL-1β production in macrophages. Mechanistically, DCA-triggered NLRP3 inflammasome activation by promoting cathepsin B release at least partially through sphingosine-1-phosphate receptor 2. Colorectal instillation of DCA significantly increased mature IL-1β level in colonic tissue and exacerbated DSS-induced colitis, while in vivo blockage of NLRP3 inflammasome or macrophage depletion dramatically reduced the mature IL-1β production and ameliorated the aggravated inflammatory injury imposed by DCA. Thus, our findings show that high-level fecal DCA may serve as an endogenous danger signal to activate NLRP3 inflammasome and contribute to HFD-related colonic inflammation. NLRP3 inflammasome may represent a new potential therapeutical target for treatment of IBD.

Expression of miRNA-21 in colonic mucosa and peripheral blood CD4+ T cells of 49 patients with active inflammatory bowel disease

Objective To investigate the role and significance of miRNA-21 in the pathogenesis and development of inflammatory bowel disease (IBD). Methods The expressions of microRNA-21 (miRNA-21) in colonic mucosa and peripheral blood CD4+ T cells were analyzed by fluorescence quantitative polymerase chain reaction (PCR) in 26 patients with active Crohn's disease (CD), 23 patients with active ulcerative colitis (UC) and 19 healthy controls. The relative expression amount of miRNA-21 in colonic mucosal and peripheral blood CD4+ T cells in 11 patients with CD was compared before and after infliximab (IFX) treatment, and its correlation with tumor necrosis factor(TNF)-α was analyzed. t-test was performed for comparison between groups. The correlation between miRNA-21 expression in peripheral blood CD4+ T cells and serum TNF-α was analyzed by Spearman correlation analysis. Results The expression of miRNA-21 in colonic mucosa of CD patients and UC patients was 4.720±0.397 and 4.993±0.415, respectively, which were both higher than that of healthy control group (1.101±0.284), and the differences were statistically significant (t=7.657 and 8.356, both P<0.01). The expression of miRNA-21 in peripheral blood CD4+ T cells of CD patients and UC patients was 3.254±0.323 and 3.450±0.311, which were both higher than that of healthy control group (0.891±0.220), and the differences were statistically significant (t=6.007 and 7.098, both P<0.01). After 12 weeks of IFX treatment, simple endoscopic score for Crohn's disease (SES-CD) of CD patients was 8.019±0.349, which was lower than that before treatment (21.502±1.185), and the difference was statistically significant (t=10.910, P<0.01). The serum TNF-α level was 61.570±6.252, which was lower than that before treatment (173.500±12.670), and the difference was statistically significant (t=7.926, P<0.01). The results of correlation analysis indicated that serum TNF-α level was positively correlated with miRNA-21 expression in peripheral blood CD4+ T cells (r=0.780 4, P<0.01). Conclusions The increasing of miRNA-21 expression in IBD was closely correlated with the serum TNF-α level and severity of inflammation. miRNA-21 might be a new target for IBD treatment. Key words: miRNA-21; Inflammatory bowel diseases; Crohn disease; Colitis, ulcerative

Splenic dendritic cell involvement in FXR-mediated amelioration of DSS colitis

Inflammatory Bowel Disease (IBD) is a multifactorial disorder involving dysregulation of the immune response and bacterial translocation through the intestinal mucosal barrier. Previously, we have shown that activation of the bile acid sensor Farnesoid X Receptor (FXR), which belongs to the family of nuclear receptors, improves experimental intestinal inflammation, decreasing expression of pro-inflammatory cytokines and protecting the intestinal barrier.Here, we aimed to investigate the immunological mechanisms that ameliorate colitis when FXR is activated. We analyzed by FACS immune cell populations in mesenteric lymph nodes (MLN) and in the spleen to understand whether FXR activation alters the systemic immune response. We show that FXR activation by obeticholic acid (OCA) has systemic anti-inflammatory effects that include increased levels of plasma IL-10, inhibition of both DSS-colitis associated decrease in splenic dendritic cells (DCs) and increase in Tregs. Impact of OCA on DC relative abundance was seen in spleen but not MLN, possibly related to the increased FXR expression in splenic DCs compared to MLN DCs. Moreover, FXR activation modulates the chemotactic environment in the colonic site of inflammation, as Madcam1 expression is decreased, while Ccl25 is upregulated. Together, our data suggest that OCA treatment elicits an anti-inflammatory immune status including retention of DCs in the spleen, which is associated with decreased colonic inflammation. Pharmacological FXR activation is therefore an attractive new drug target for treatment of IBD.

The Contribution of CD40/CD40L Axis in Inflammatory Bowel Disease: An Update.

Inflammatory bowel disease (IBD) is a chronic and multifactorial disease of the gastrointestinal tract. The exact etiology of IBD remains complex and unclear involving an inadequately defined relationship between microbial insult, genetic predisposition, altered intestinal barrier permeability, oxidative stress components and abnormal immune responses. The role of the co-stimulatory system made up of cluster of differentiation 40 protein (CD40) and its ligand (CD40L) in the response of the immune system to pathogens is now widely accepted. The implication of CD40/CD40L axis in immune system disorders due to its important role as signal transduction pathway among immune cells is well documented. Several studies have suggested that CD40/CD40L interactions regulate oxidative stress; this can affect various signaling pathways leading to IBD development. Hence, CD40/CD40L signaling pathway may become a new target for IBD treatment. This review will cover the general contribution of the CD40/CD40L dyad in the development of IBD in order to facilitate future approaches aiming to elucidate the immunological mechanisms that control gut inflammation.

IL-7 promotes long-term in vitro survival of unique long-lived memory subset generated from mucosal effector memory CD4+ T cells in chronic colitis mice

Colitogenic memory CD4+ T cells are important in the pathogenesis of inflammatory bowel disease (IBD). Although memory stem cells with high survival and self-renewal capacity were recently identified in both mice and humans, it is unclear whether a similar subset is present in chronic colitis mice. We sought to identify and purify a long-lived subset of colitogenic memory CD4+ T cells, which may be targets for treatment of IBD. A long-lived subset of colitogenic memory CD4+ T cells was purified using a long-term culture system. The characteristics of these cells were assessed. Interleukin (IL)-7 promoted the in vitro survival for >8 weeks of lamina propria (LP) CD4+ T cells from colitic SCID mice previously injected with CD4+CD45RBhigh T cells. These cells were in a quiescent state and divided a maximum of 5 times in 4 weeks. LP CD4+ T cells expressed higher levels of Bcl-2, integrin-α4β7, CXCR3 and CD25 after than before culture, as well as secreting high concentrations of IL-2 and low concentrations of IFN-γ and IL-17 in response to intestinal bacterial antigens. LP CD4+ T cells from colitic mice cultured with IL-7 for 8 weeks induced more severe colitis than LP CD4+ T cells cultured for 4 weeks. We developed a novel culture system to purify a long-lived, highly pathogenic memory subset from activated LP CD4+ T cells. IL-7 promoted long-term in vitro survival of this subset in a quiescent state. This subset will be a novel, effective target for the treatment of IBD.

Colitis-Associated Adipose Tissue Responses to Corticotropin-Releasing Hormone Family of Neuropeptides

Background and Aims: Numerous studies have indicated that adipose tissue is an active endocrine organ and several adipose-associated molecules have been implicated as potential mediators of intestinal inflammation. Results from our group and others indicate that corticotrophin releasing hormone (CRH or CRF), and its peptide family members urocortins (UCNs) participate in the pathophysiology of intestinal inflammation and inflammatory bowel disease (IBD). Recent evidence also indicates that CRH receptors 1 and 2 are expressed by human adipocytes. Whether these ligands and receptors are expressed in the mesenteric fat and are modulated during colitis has never been studied. Here we compared levels of expression of the CRH peptide family at in the mesenteric fat depots of mice before and after experimental TNBS-induced colitis. We also exposed isolated human mesenteric preadipocytes to CRH and measured changes in cytokine production at the mRNA and protein levels. Methods: C57BL6 mice (n=10 per group) were injected intracolonically with either vehicle (40% ethanol, control) or TNBS (5 mg/20 grams) for 48 hr. Mesenteric adipose tissue was harvested from the mice and mRNA was isolated and converted to cDNA for real time RT PCR. Human mesenteric pre-adipocytes grown in culture were stimulated with 100nM CRH for 8 hours. Supernatants were collected for protein array and ELISA while mRNA was isolated for conversion to cDNA and use in real time RT PCR experiments. Data were analyzed using a two tailedMannWhitney test. Results: CRHmRNAwas significantly increased inmesenteric fat of TNBS-exposed mice compared to controls (by 112.9 fold, p<0.01). UCNs 2 and 3 were also significantly increased in these tissues (by 30.7 and 9.2 fold, p< 0.0016 and p< 0.0052, respectively). Protein arrays on CRH stimulated human mesenteric preadipocytes showed increased secretion of TIMP-2 and Rantes (CCL5 gene product) and decreased MIF, MCP-3 and PAI-1 levels. Changes in released MIF were also confirmed by ELISA in the medium of preadipocytes (p< 0.01). Conclusions: Increased expression of CRH and urocortins in adipose tissue during colitis together with the ability of CRH to induce changes in cytokine release from isolated adipocytes suggest that the CRH family of peptides may mediate inflammatory responses in mesenteric fat and affect the development of intestinal inflammation. These findings may represent a novel signaling pathway in colitis and could have important implications for inflammatory bowel disease treatment targets. Research Support: NIH NIDDK T32 DK07180-36 Gastroenterology Training Grant and P01 DK 33506

Blockage of angiotensin II type 1 receptor regulates TNF-α-induced MAdCAM-1 expression via inhibition of NF-κB translocation to the nucleus and ameliorates colitis

Mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) is an important target in the treatment of inflammatory bowel disease (IBD). Recently, treatment of IBD with an antibody to alpha4beta7-integrin, a ligand for MAdCAM-1, has been an intense focus of research. Our aim was to clarify the mechanism by which MAdCAM-1 is regulated via angiotensin II type 1 receptor (AT1R), and to verify if AT1R might be a novel target for IBD treatment. The role of AT1R in the expression of MAdCAM-1 in SVEC (a murine high endothelial venule cell) and MJC-1 (a mouse colonic endothelial cell) was examined following cytokine stimulation. We further evaluated the effect of AT1R on the pathogenesis of immune-mediated colitis using AT1R-deficient (AT1R-/-) mice and a selective AT1R blocker. AT1R blocker significantly suppressed MAdCAM-1 expression induced by TNF-alpha, but did not inhibit phosphorylation of p38 MAPK or of IkappaB that modulate MAdCAM-1 expression. However, NF-kappaB translocation into the nucleus was inhibited by these treatments. In a murine colitis model induced by dextran sulfate sodium, the degree of colitis, judged by body weight loss, histological damage, and the disease activity index, was much milder in AT1R-/- than in wild-type mice. The expression of MAdCAM-1 was also significantly lower in AT1R-/- than in wild-type mice. These results suggest that AT1R regulates the expression of MAdCAM-1 under colonic inflammatory conditions through regulation of the translocation of NF-kappaB into the nucleus. Furthermore, inhibition of AT1R ameliorates colitis in a mouse colitis model. Therefore, AT1R might be one of new therapeutic target of IBD via regulation of MAdCAM-1.