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BackgroundConstitutive Wnt activation is essential for colorectal cancer (CRC) initiation but also underlies the cancer stem cell phenotype, metastasis and chemosensitivity. Importantly Wnt activity is still modulated as evidenced by higher Wnt activity at the invasive front of clonal tumours termed the β-catenin paradox. SMAD4 and p53 mutation status and the bone morphogenetic protein (BMP) pathway are known to affect Wnt activity. The combination of SMAD4 loss, p53 mutations and BMP signalling may integrate to influence Wnt signalling and explain the β-catenin paradox.MethodsWe analysed the expression patterns of SMAD4, p53 and β-catenin at the invasive front of CRCs using immunohistochemistry. We activated BMP signalling in CRC cells in vitro and measured BMP/Wnt activity using luciferase reporters. MTT assays were performed to study the effect of BMP signalling on CRC chemosensitivity.ResultsEighty-four percent of CRCs with high nuclear β-catenin staining are SMAD4 negative and/or p53 aberrant. BMP signalling inhibits Wnt signalling in CRC only when p53 and SMAD4 are unaffected. In the absence of SMAD4, BMP signalling activates Wnt signalling. When p53 is lost or mutated, BMP signalling no longer influences Wnt signalling. The cytotoxic effects of 5-FU are influenced in a similar manner.ConclusionsThe BMP signalling pathway differentially modulates Wnt signalling dependent on the SMAD4 and p53 status. The use of BMPs in cancer therapy, as has been proposed by previous studies, should be targeted to individual cancers based on the mutational status of p53 and SMAD4.

Chronic liver injury leads to the accumulation of myofibroblasts resulting in increased collagen deposition and hepatic fibrogenesis. Treatments specifically targeting fibrogenesis are not yet available. Mesenchymal stromal cells (MSCs) are fibroblast-like stromal (stem) cells, which stimulate tissue regeneration and modulate immune responses. In the present study we assessed whether liver fibrosis and cirrhosis can be reversed by treatment with MSCs or fibroblasts concomitant to partial hepatectomy (pHx)-induced liver regeneration. After carbon tetrachloride-induced fibrosis and cirrhosis, mice underwent a pHx and received either systemically or locally MSCs in one of the two remaining fibrotic/cirrhotic liver lobes. Eight days after treatment, liver fibrogenesis was evaluated by Sirius-red staining for collagen deposition. A significant reduction of collagen content in the locally treated lobes of the regenerated fibrotic and cirrhotic livers was observed in mice that received high dose MSCs. In the non-MSC-treated counterpart liver lobes no changes in collagen deposition were observed. Local fibroblast administration or intravenous administration of MSCs did not ameliorate fibrosis. To conclude, local administration of MSCs after pHx, in contrast to fibroblasts, results in a dose-dependent on-site reduction of collagen deposition in mouse models for liver fibrosis and cirrhosis., (© 2019 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Patients frequently wonder whether their dietary pattern influences the course of inflammatory bowel disease (IBD). Many patients even avoid certain foods that aggravate their symptoms. Although interest in nutritional interventions is rising among physicians, the current application of nutritional interventions in the IBD population is limited due to the lack of scientific evidence from clinical trials. Several studies, however, have identified associations between diet, gut microbiota, intestinal epithelial integrity, and mucosal immune responses. In patients consuming predominantly a Western diet high in n-6 poly-unsaturated fatty acids (PUFAs), sugars, and meat, and low in fruits and vegetables, an impaired gut epithelial barrier and disturbances in the intestinal microbiota have been observed, resulting in a chronic mucosal inflammation. An anti-inflammatory diet may restore this disbalance. In this review, we discuss the effects of diet on the composition of the microbiota, the gut epithelial barrier function, and the mucosal immune system.

Inflammatory intestinal diseases are characterized by abnormal immune responses and affect distinct locations of the gastrointestinal tract. Although the role of several immune subsets in driving intestinal pathology has been studied, a system-wide approach that simultaneously interrogates all major lineages on a single-cell basis is lacking. We used high-dimensional mass cytometry to generate a system-wide view of the human mucosal immune system in health and disease. We distinguished 142 immune subsets and through computational applications found distinct immune subsets in peripheral blood mononuclear cells and intestinal biopsies that distinguished patients from controls. In addition, mucosal lymphoid malignancies were readily detected as well as precursors from which these likely derived. These findings indicate that an integrated high-dimensional analysis of the entire immune system can identify immune subsets associated with the pathogenesis of complex intestinal disorders. This might have implications for diagnostic procedures, immune-monitoring, and treatment of intestinal diseases and mucosal malignancies., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background & Aims: Patients with perianal fistulizing Crohn's disease have a poor prognosis because these lesions do not heal well. We evaluated the effects of local administration of bone marrow-derived mesenchymal stromal cells (MSCs) to these patients from healthy donors in a double-blind, placebo-controlled study., Methods: Twenty-one patients with refractory perianal fistulizing Crohn's disease were randomly assigned to groups given injections of 1 × 10(7) (n = 5, group 1), 3 × 10(7) (n = 5, group 2), or 9 × 10(7) (n = 5, group 3) MSCs, or placebo (solution with no cells, n = 6), into the wall of curettaged fistula, around the trimmed and closed internal opening. The primary outcome, fistula healing, was determined by physical examination 6, 12, and 24 weeks later; healing was defined as absence of discharge and <2 cm of fluid collection-the latter determined by magnetic resonance imaging at week 12. All procedures were performed at Leiden University Medical Center, The Netherlands, from June 2012 through July 2014., Results: No adverse events were associated with local injection of any dose of MSCs. Healing at week 6 was observed in 3 patients in group 1 (60.0%), 4 patients in group 2 (80.0%), and 1 patient in group 3 (20.0%), vs 1 patient in the placebo group (16.7%) (P = .08 for group 2 vs placebo). At week 12, healing was observed in 2 patients in group 1 (40.0%), 4 patients in group 2 (80.0%), and 1 patient in group 3 (20.0%), vs 2 patients in the placebo group (33.3%); these effects were maintained until week 24 and even increased to 4 (80.0%) in group 1. At week six, 4 of 9 individual fistulas had healed in group 1 (44.4%), 6 of 7 had healed in group 2 (85.7%), and 2 of 7 had healed in group 3 (28.6%) vs 2 of 9 (22.2%) in the placebo group (P = .04 for group 2 vs placebo). At week twelve, 3 of 9 individual fistulas had healed in group 1 (33.3%), 6 of 7 had healed in group 2 (85.7%), 2 of 7 had healed in group 3 (28.6%), and 3 of 9 had healed in the placebo group (33.3%). These effects were stable through week 24 and even increased to 6 of 9 (66.7%) in group 1 (P = .06 group 2 vs placebo, weeks 12 and 24)., Conclusions: Local administration of allogeneic MSCs was not associated with severe adverse events in patients with perianal fistulizing Crohn's disease. Injection of 3 × 10(7) MSCs appeared to promote healing of perianal fistulas. ClinicalTrials.gov ID NCT01144962., (Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.)

The ability of mesenchymal stromal cells (MSCs) to suppress immune responses combined with their potential to actively participate in tissue repair provides a strong rationale for the use of MSCs as a new treatment option in diseases characterized by inflammation and severe tissue damage, such as Crohn's disease (CD) and perianal fistulas. Multiple studies have shown that MSCs suppress a range of immune cells, such as dendritic cells (DC), naïve and effector T cells, and natural killer (NK) cells. Recently published papers attribute the immunosuppressive capacity of MSCs to soluble factors produced by MSCs, such as prostaglandin E2 (PGE(2)), inducible nitric oxide synthase (iNOS), and indoleamine 2,3-dioxygenase (IDO). Promising results are obtained from phase I and II clinical trials with autologous and allogeneic MSCs as treatment for refractory CD and perianal fistulas; however the question remains: what are the molecular mechanisms underlying the immunomodulating properties of MSCs? This paper highlights the present knowledge on the immunosuppressive effects of MSCs and its complexity in relation to CD and perianal fistulas.

Background and Aims: Mesenchymal stromal cells (MSC) have both multilineage differentiation capacity and immunosuppressive properties. Promising results with MSC administration have been obtained in experimental colitis. Clinical application of MSC for the treatment of inflammatory bowel disease (IBD) is currently under investigation in phase I-III trials in patients with past or concurrent immunomodulating therapy. However, little is known about MSC interactions with these immunosuppressive drugs. To address this issue we studied the combined effect of MSC and IBD drugs in in vitro functionality assays., Methods: The effects of azathioprine, methotrexate, 6-mercaptopurine and anti-tumor necrosis factor (TNF)-α on MSC phenotype, survival, differentiation capacity and immunosuppressive capacity were studied., Results: MSC exposed to physiologically relevant concentrations of IBD drugs displayed a normal morphology and fulfilled phenotypic and functional criteria for MSC. Differentiation into adipocyte and osteocyte lineages was not affected and cells exhibited normal survival after exposure to the various drugs. MSC suppression of peripheral blood mononuclear cell (PBMC) proliferation in vitro was not hampered by IBD drugs. In fact, in the presence of 6-mercaptopurine and anti-TNF-α antibodies, the inhibitory effect of this drug alone was enhanced, suggesting an additive effect of pharmacotherapy and MSC treatment., Conclusions: This study demonstrates that, in vitro, MSC phenotype and function are not affected by therapeutic concentrations of drugs commonly used in the treatment of IBD. These findings are important for the potential clinical use of MSC in combination with immunomodulating drugs and anti-TNF-α therapy.

Mesenchymal stromal cells (MSCs) are currently under investigation for the treatment of inflammatory disorders, including Crohn's disease. MSCs are pluripotent cells with immunosuppressive properties. Recent data suggest that resting MSCs do not have significant immunomodulatory activity, but that the immunosuppressive function of MSCs has to be elicited by interferon-γ (IFN-γ). In this article, we assessed the effects of IFN-γ prestimulation of MSCs (IMSCs) on their immunosuppressive properties in vitro and in vivo. To this end, we pretreated MSCs with IFN-γ and assessed their therapeutic effects in dextran sodium sulfate (DSS)- and trinitrobenzene sulfonate (TNBS)-induced colitis in mice. We found that mice treated with IMSCs (but not MSCs) showed a significantly attenuated development of DSS-induced colitis. Furthermore, IMSCs alleviated symptoms of TNBS-induced colitis. IMSC-treated mice displayed an increase in body weight, lower colitis scores, and better survival rates compared with untreated mice. In addition, serum amyloid A protein levels and local proinflammatory cytokine levels in colonic tissues were significantly suppressed after administration of IMSC. We also observed that IMSCs showed greater migration potential than unstimulated MSCs to sites within the inflamed intestine. In conclusion, we show that prestimulation of MSCs with IFN-γ enhances their capacity to inhibit Th1 inflammatory responses, resulting in diminished mucosal damage in experimental colitis. These data demonstrate that IFN-γ activation of MSCs increases their immunosuppresive capacities and importantly, their therapeutic efficacy in vivo., (Copyright © 2011 AlphaMed Press.)