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P-005: Mechanism of action of potential live biotherapeutics for the treatment of inflammatory bowel disease
Abstracts of the 3rd International Symposium on Pediatric Inflammatory Bowel Disease contrast, BCoAT butyrate producers were reduced in CD with active inflammation (p < 0.05) but not in CD with normal mucosa (P > 0.05). Conclusion: Alterations in relative abundance of butyrate producers could be a susceptibility factor for development of mucosal inflammation. P-003 Detection of bacterial and host proteins from a single colonic biopsy sample by a new mass spectrometry-based assay in pediatric ulcerative colitis M. Kalliom¨ aki1 *, P. Kouvonen2 , C.C. Koh3 , B. Collins3 , L. Malmstr¨ om3 , R. Aebersold3 . 1 Turku University Hospital, Turku, Finland, 2 Turku Centre for Biotechnology, Turku, Finland, 3 Institute of Molecular Systems Biology, ETH Z¨ urich, Z¨ urich, Switzerland Introduction: Demonstration of microbial imbalance and abnormal activation of receptors recognizing different microbial patterns in ulcerative colitis (UC) suggests an important role of host microbe interaction in the pathogenesis of the condition. It would thus be important to have a method that would allow a simultaneous analysis of both host and bacterial proteins from a single sample. Aim: To test the capability of a newly developed mass spectrometry (MS)-based assay (PCT-SWATH-MS) to characterize inflamed and non-inflamed colon tissue based on the differences in host and bacterial protein expression levels across a small patient cohort. Methods: Colonoscopy was done to 8 adolescents (median age 15 years; range 13 17 years) due to a suspicion of UC (5 cases: 3 new UC and 2 non-inflammatory controls) or a routine checkup of the condition (3 cases: 1 active and 2 inactive UC). In addition to routine biopsies, a biopsy for a MS-based assay was taken both from cecum and rectum in all the patients. Results: Total 5707 human (226 bacterial) proteins were identified and 4720 human (151 bacterial) proteins were quantified across all the patients. Both inflammatory status of the patient and location of the biopsy had a major effect on the expression of host and bacterial proteins. Conclusion: A new MS-based assay was utilized successfully in a cohort of UC patients to analyze expression of both host and bacterial proteins from a single colonic biopsy sample. Further studies are warranted to evaluate the application of the assay in larger clinical settings. P-004 Altered Pregnane X Receptor (PXR) expression in children with active Crohn’s disease V. Shakhnovich *. Children’s Mercy Hospital, Kansas City, MO, United States of America Introduction: PXR is a nuclear receptor responsible for transcriptional regulation of important drug metabolizing enzymes (DME). Its dysregulation has been implicated in IBD, yet data on PXR expression in intestinal tissue of children with Crohn’s disease (CD) remain limited. Aim: To examine PXR expression in the small intestine of children with and without CD. Methods: RNA was extracted from archived paraffin-embedded intestinal biopsies from children with CD (7 18 yrs, n = 18) and age-, sex-matched Controls (n = 12). Samples meeting mRNA standards (3 :5 GAPDH ratio <10) were included. PXR expression was assessed via RT-qPCR in inflamed terminal ileum (TI) vs. non-inflamed duodenum (duod). Relative mRNA expression was normalized to GAPDH and log transformed; differences explored via paired t-tests. Results: PXR expression was decreased in inflamed TI vs. noninflamed duod (TI = 1.88±0.89 vs. duod = 2.5±0.67; p = 0.0003) in CD, but not Controls (TI = 2.11±0.41 vs. duod = 2.26±0.61; p = 0.52). CYP3A4 expression (DME target of PXR) was decreased
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in CD (TI = 0.89±3.11 vs. duod = 1.90±2.29; p = 0.014), but not Controls (TI = 2.46±0.51 vs. duod = 2.60±0.60; p = 0.61), as was villin, an indicator of epithelial cell integrity (CD TI = 3.80±0.94 vs. duod = 4.61±0.52; p = 0.0002; Control TI = 4.30±0.35 vs. duod = 4.47±0.40; p = 0.29). GAPDH expression did not differ with age, sex, or location in CD or Controls. PXR expression correlated with villin across all samples (r2 = 0.780, p = 0.01). Conclusion: PXR expression is decreased in inflamed vs. non-inflamed tissue in CD and likely contributes to the downregulation of intestinal DMEs (e.g., CYP3A4) important to the treatment of IBD. The coordinate downregulation of PXR and Villin suggests that epithelial cell integrity may be important to therapeutic response. P-005 Mechanism of action of potential live biotherapeutics for the treatment of inflammatory bowel disease I.E. Mulder *, A.M. Patterson, R.I. Aminov, E. Logan, M.I. Delday, A.G.P. Coutts, G. Grant, D. Kelly. University of Aberdeen, Aberdeen, United Kingdom Disruption of the gut microbiota shows consistent correlation with susceptibility to Crohn’s Disease and Ulcerative Colitis. Specific members of the healthy gut microbiota can influence immune homeostasis in a variety of ways. For instance, bacteria can skew the composition of the microbiota, strengthen gut barrier function, and drive maturation of intestinal T cell subsets. We investigated the immune-potentiating effects of a number of candidate commensal bacterial strains, with specific emphasis on the mode of action and protection against IBD in mouse models of colitis. Bacterial strains were studied in vitro (intestinal cell culture systems) and in vivo (acute and chronic colitis in mice). Characterization of host bacterial interactions was performed using a multi-omics approach, including bacterial genomics, microarrays and FACS analysis. Two potential live biotherapeutic bacterial strains work in distinct ways to induce immune homeostasis. One strain directly influences the NF-úB intracellular signalling cascade to reduce the pro-inflammatory response. The other strain is able to induce the expansion of CD3+CD4+CD25+FoxP3+ regulatory T cells through secreted and cell surface-associated molecules. Candidate bacterial strains have been identified that provide protection against murine IBD through distinctive mechanisms. Translation of their important immune-regulatory effects into human systems will now be assessed. P-006 The effect of exclusive enteral nutrition on the microbiota of newly diagnosed pediatric Crohn’s disease patients N.O. Kaakoush1 , A.S. Day2 *, S.T. Leach1 , D.A. Lemberg3 , S. Nielsen1 , H.M. Mitchell1 . 1 The University of New South Wales, Sydney, Australia, 2 University of Otago, Christchurch, New Zealand, 3 Sydney Children’s Hospital, Sydney, Australia Exclusive enteral nutrition (EEN) is commonly used to treat pediatric Crohn’s disease (CD). Meta-analysis of pediatric studies which have compared the effect of EEN with other treatments has shown that EEN induces remission in up to 80 85% of patients. To gain a comprehensive understanding of the effect of EEN on the microbiota of CD patients, we used 16S rRNA gene and whole genome high throughput sequencing (HTS) to determine changes in the fecal microbiota of 5 CD children, before, during and after EEN therapy and compared this with 5 healthy controls. The microbial diversity observed in CD patients tended to be lower than that in controls (CD: 2.25±0.24, controls:
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in CD (TI = 0.89±3.11 vs. duod = 1.90±2.29; p = 0.014), but not Controls (TI = 2.46±0.51 vs. duod = 2.60±0.60; p = 0.61), as was villin, an indicator of epithelial cell integrity (CD TI = 3.80±0.94 vs. duod = 4.61±0.52; p = 0.0002; Control TI = 4.30±0.35 vs. duod = 4.47±0.40; p = 0.29). GAPDH expression did not differ with age, sex, or location in CD or Controls. PXR expression correlated with villin across all samples (r2 = 0.780, p = 0.01). Conclusion: PXR expression is decreased in inflamed vs. non-inflamed tissue in CD and likely contributes to the downregulation of intestinal DMEs (e.g., CYP3A4) important to the treatment of IBD. The coordinate downregulation of PXR and Villin suggests that epithelial cell integrity may be important to therapeutic response. P-005 Mechanism of action of potential live biotherapeutics for the treatment of inflammatory bowel disease I.E. Mulder *, A.M. Patterson, R.I. Aminov, E. Logan, M.I. Delday, A.G.P. Coutts, G. Grant, D. Kelly. University of Aberdeen, Aberdeen, United Kingdom Disruption of the gut microbiota shows consistent correlation with susceptibility to Crohn’s Disease and Ulcerative Colitis. Specific members of the healthy gut microbiota can influence immune homeostasis in a variety of ways. For instance, bacteria can skew the composition of the microbiota, strengthen gut barrier function, and drive maturation of intestinal T cell subsets. We investigated the immune-potentiating effects of a number of candidate commensal bacterial strains, with specific emphasis on the mode of action and protection against IBD in mouse models of colitis. Bacterial strains were studied in vitro (intestinal cell culture systems) and in vivo (acute and chronic colitis in mice). Characterization of host bacterial interactions was performed using a multi-omics approach, including bacterial genomics, microarrays and FACS analysis. Two potential live biotherapeutic bacterial strains work in distinct ways to induce immune homeostasis. One strain directly influences the NF-úB intracellular signalling cascade to reduce the pro-inflammatory response. The other strain is able to induce the expansion of CD3+CD4+CD25+FoxP3+ regulatory T cells through secreted and cell surface-associated molecules. Candidate bacterial strains have been identified that provide protection against murine IBD through distinctive mechanisms. Translation of their important immune-regulatory effects into human systems will now be assessed. P-006 The effect of exclusive enteral nutrition on the microbiota of newly diagnosed pediatric Crohn’s disease patients N.O. Kaakoush1 , A.S. Day2 *, S.T. Leach1 , D.A. Lemberg3 , S. Nielsen1 , H.M. Mitchell1 . 1 The University of New South Wales, Sydney, Australia, 2 University of Otago, Christchurch, New Zealand, 3 Sydney Children’s Hospital, Sydney, Australia Exclusive enteral nutrition (EEN) is commonly used to treat pediatric Crohn’s disease (CD). Meta-analysis of pediatric studies which have compared the effect of EEN with other treatments has shown that EEN induces remission in up to 80 85% of patients. To gain a comprehensive understanding of the effect of EEN on the microbiota of CD patients, we used 16S rRNA gene and whole genome high throughput sequencing (HTS) to determine changes in the fecal microbiota of 5 CD children, before, during and after EEN therapy and compared this with 5 healthy controls. The microbial diversity observed in CD patients tended to be lower than that in controls (CD: 2.25±0.24, controls: