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Background & Aims: Variants in the genes ATG16L1 and IRGM affect autophagy and are associated with the development of Crohn's disease. It is not clear how autophagy is linked to loss of immune tolerance in the intestine. We investigated the involvement of the immunologic synapse-the site of contact between dendritic cells (DCs) and T cells, which contains molecules involved in antigen recognition and regulates immune response., Methods: DC autophagy was reduced using small interfering RNAs or pharmacologic inhibitors. DC phenotype and function were analyzed by confocal microscopy, time-lapse microscopy, and flow cytometry. We also examined DCs isolated from patients with Crohn's disease who carried the ATG16L1 risk allele., Results: Immunologic synapse formation induced formation of autophagosomes in DCs; the autophagosomes were oriented toward the immunologic synapse and contained synaptic components. Knockdown of ATG16L1 and IRGM with small interfering RNAs in DCs resulted in hyperstable interactions between DCs and T cells, increased activation of T cells, and activation of a T-helper 17 cell response. LKB1 was recruited to the immunologic synapse, and induction of autophagy in DC required inhibition of mammalian target of rapamycine signaling by the LKB1-AMP activated protein kinase (AMPK) pathway. DCs from patients with Crohn's disease who had an ATG16L1 risk allele had a similar hyperstability of the immunologic synapse., Conclusions: Autophagy is induced upon formation of the immunologic synapse and negatively regulates T-cell activation. This mechanism might increase adaptive immunity in patients with Crohn's disease who carry ATG16L1 risk alleles., (Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background & Aims: Functional abdominal pain (FAP) and irritable bowel syndrome (IBS) are highly prevalent in childhood. A substantial proportion of patients continues to experience long-lasting symptoms. Gut-directed hypnotherapy (HT) has been shown to be highly effective in the treatment of adult IBS patients. We undertook a randomized controlled trial and compared clinical effectiveness of HT with standard medical therapy (SMT) in children with FAP or IBS., Methods: Fifty-three pediatric patients, age 8-18 years, with FAP (n = 31) or IBS (n = 22), were randomized to either HT or SMT. Hypnotherapy consisted of 6 sessions over a 3-month period. Patients in the SMT group received standard medical care and 6 sessions of supportive therapy. Pain intensity, pain frequency, and associated symptoms were scored in weekly standardized abdominal pain diaries at baseline, during therapy, and 6 and 12 months after therapy., Results: Pain scores decreased significantly in both groups: from baseline to 1 year follow-up, pain intensity scores decreased in the HT group from 13.5 to 1.3 and in the SMT group from 14.1 to 8.0. Pain frequency scores decreased from 13.5 to 1.1 in the HT group and from 14.4 to 9.3 in the SMT group. Hypnotherapy was highly superior, with a significantly greater reduction in pain scores compared with SMT (P < .001). At 1 year follow-up, successful treatment was accomplished in 85% of the HT group and 25% of the SMT group (P < .001)., Conclusions: Gut-directed HT is highly effective in the treatment of children with longstanding FAP or IBS.

Background & Aims: The intestinal epithelium must discriminate between pathogenic and nonpathogenic bacteria and respond accordingly. The aim of this study was to examine whether bacterial DNA can serve as the molecular basis for bacterial recognition., Methods: HT-29 monolayers were treated with various bacterial DNA and interleukin (IL)-8 secretion measured by enzyme-linked immunosorbent assay, nuclear factor kappaB activation by electrophoretic mobility shift assay and reporter assays, and IkappaB levels by Western blotting. Cytokine secretion in response to bacterial DNA was measured in murine colonic segments and splenocytes. IL-10-deficient mice were fed DNA from VSL probiotic compound daily for 2 weeks. Colons were removed and analyzed for cytokine production and inflammation., Results: HT-29 cells responded with IL-8 secretion to bacterial DNA in a differential manner. In the presence of proinflammatory stimuli, VSL3 DNA inhibited IL-8 secretion, reduced p38 mitogen-activated protein kinase activation, delayed nuclear factor kappaB activation, stabilized levels of IkappaB, and inhibited proteasome function. VSL3 DNA inhibited colonic interferon (IFN)-gamma secretion in mouse colons and also attenuated a Bacteroides vulgatus-induced IFN-gamma release from murine splenocytes. In mice, VSL3 DNA attenuated a systemic release of tumor necrosis factor alpha in response to Escherichia coli DNA injection. Treatment of IL-10-deficient mice with oral VSL3 DNA resulted in a reduction in mucosal secretion of tumor necrosis factor alpha and IFN-gamma and an improvement in histologic disease., Conclusions: DNA from probiotic bacteria can limit epithelial proinflammatory responses in vivo and in vitro. Systemic and oral administration of VSL3 DNA ameliorates inflammatory responses.

Background & Aims: The probiotic compound, VSL#3, is efficacious as maintenance therapy in pouchitis and ulcerative colitis. The aim of this study was to determine the efficacy of VSL#3 as a primary therapy in the treatment of colitis in the interleukin (IL)-10 gene-deficient mouse. Mechanisms of action of VSL#3 were investigated in T(84) monolayers., Methods: IL-10 gene-deficient and control mice received 2.8 x 10(8) colony-forming units per day of VSL#3 for 4 weeks. Colons were removed and analyzed for cytokine production, epithelial barrier function, and inflammation. VSL#3 or conditioned media was applied directly to T(84) monolayers., Results: Treatment of IL-10 gene-deficient mice with VSL#3 resulted in normalization of colonic physiologic function and barrier integrity in conjunction with a reduction in mucosal secretion of tumor necrosis factor alpha and interferon gamma and an improvement in histologic disease. In vitro studies showed that epithelial barrier function and resistance to Salmonella invasion could be enhanced by exposure to a proteinaceous soluble factor secreted by the bacteria found in the VSL#3 compound., Conclusions: Oral administration of VSL#3 was effective as primary therapy in IL-10 gene-deficient mice, and had a direct effect on epithelial barrier function.