Project description:Crohn’s disease arises through host-environment interaction, with abnormal gene expression resulting from disturbed pathway activation or response to bacteria. Single cell RNA-sequencing of ileal tissue from 2 paediatric Crohn’s disease patients was performed, identifying populations of CD8+ effector memory T cells (CD8+ Tem), memory B-cells, monocytes, epithelial cells and plasma cells within the ileal tissue. Specialised epithelial cells driving differential expression of S100A8 and S100A9 and associated with defence to bacterium were identified, as well as IL17-signalling associated pathways in monocyte and epithelial cell populations.
Project description:Pouchitis is a common complication for ulcerative colitis (UC) patients with ileal pouch-anal anastomosis (IPAA) surgery. Similarly to IBD, both innate host factors such as genetics, and environmental stimuli including the tissue-associated microbiome have been implicated in the pathogenesis. In this study, we make use of the IPAA model of inflammatory bowel disease (IBD) to carry out a study associating mucosal host gene expression with the microbiome and corresponding clinical outcomes. In order to determine how host gene expression might influence, or be influenced by the tissue associated microbiome, we analyzed 205 IPAA patients with biopsies collected from the pouch and afferent limb for host transcriptomics and 16S rDNA gene sequencing. Metadata included antibiotic use, inflammation score, and clinical classification. To achieve power for a genome-wide microbiome-transcriptome association study, we used principal component analysis to reduce OTUs and host transcripts to eigengenes and eigenclades explaining 50% of observed variance. These were subsequently tested for significant covariation with one another and/or outcome using multivariate linear modeling.
Project description:We sought to identify proteins that enable differentiation between CD and UC in children with new onset IBD. Mucosal biopsies were obtained from children undergoing baseline diagnostic endoscopy prior to therapeutic interventions. Using a super-stable isotope labeling with amino acids in cell culture (SILAC)-based approach, the proteomes of 99 paediatric control and biopsies of patients with CD and UC were compared. Multivariate analysis of a subset of these (n=50) was applied to identify novel biomarkers, which were validated in a second subset (n=49). In the discovery cohort, a panel of five proteins was sufficient to distinguish control from IBD-affected tissue biopsies with an AUC of 1.0 (95% CI 0.99 to 1.0); a second panel of 12 proteins segregated inflamed CD from UC within an AUC of 0.95 (95% CI 0.86 to 1.0). Application of the two panels to the validation cohort resulted in accurate classification of 95.9% (IBD from control) and 80% (CD from UC) of patients. 116 proteins were identified to have correlation with the severity of disease, four of which were components of the two panels, including visfatin and metallothionein-2. This study has identified two panels of candidate biomarkers for the diagnosis of IBD and the differentiation of IBD subtypes to guide appropriate therapeutic interventions in paediatric patients.
Project description:The aim of this study is to identify early pathogenic changes in ileal gene expression that precede the development of macroscopic disease in inflammatory bowel diseases (IBDs). We focused on two IBD phenotypes that were unlikely to overlap: 1) ileal Crohn’s disease (CD) patients undergoing initial ileocolic resection of diseased ileum; and 2) ulcerative colitis (UC) patients undergoing total colectomy. The Control patients were those patients without IBD undergoing initial right hemicolectomy or total colectomy. In order to identify early pathogenic changes in the human ileum in inflammatory bowel diseases, we analyzed 99 two-color whole human genome expression profiles (Agilent 4410A) of a test human ileal cRNA probe vs. a common reference human ileal RNA from a Control patient (N17). A minimum of four biopsies were taken from the macroscopically disease-unaffected proximal ileal margin of freshly resected specimens from 47 ileal Crohn's disease patients undergoing initial ileocolic resection, 27 ulcerative colitis patients undergoing total colectomy and 25 Control patients undergoing either right hemicolectomy or total colectomy. The test and common reference probes were synthesized using the Agilent Low Input Linear Amplification Kit. Hybridization was carried out in DNA hybridization chambers, washed and scanned on an Axon GenePix 4000B scanner. The preprocessing, filtering and normalization of the array data was carried out using the R package LIMMA.
Project description:CD11b+ cells isolated from IBD patient biopsies have distinct transcriptomic signatures based on their location along the GI tract, inflammation status, IBD type, and medication response. These cells also respond to JAK inhibitors by decreasing cytokine output.
Project description:Purpose: To uncover differentially-regulated transcripts and pathways/biological processes in newly-diagnosed, pediatric Crohn's disease in comparison to healthy controls. Methods: Intestinal epithelial cells were dissociated from ileal endoscopic biopsies, and stored at -80C in RNAlater. The polyA RNA fraction was purified, and single-end, 50 bp reads were sequenced and aligned to the Hg19 genome using the TopHat2 aligner. Differential analysis was performed using Bioconductor packages including edgeR, where significance was defined as p<0.05 and fold change>2. Results: We obtained 15788 reasonably-expressed transcripts that were included in differential analyses. Conclusions: Our study characterizes the dysregulation of intestinal epithelial cells in treatment-naïve Crohn's disease using RNA sequencing for transcriptomic profile of cells obtained through ileal endoscopic biopsies.
Project description:The aim of this study is to identify early pathogenic changes in ileal gene expression that precede the development of macroscopic disease in inflammatory bowel diseases (IBDs). We focused on two IBD phenotypes that were unlikely to overlap: 1) ileal Crohn’s disease (CD) patients undergoing initial ileocolic resection of diseased ileum; and 2) ulcerative colitis (UC) patients undergoing total colectomy. The Control patients were those patients without IBD undergoing initial right hemicolectomy or total colectomy.
Project description:Study 1: Transcriptomic profiles in colon tissue from inflammatory bowel diseases patients in relation to N-nitroso compound exposure and colorectal cancer risk Study 1: N-nitroso compounds (NOC) have been suggested to play a role in human cancer development but definitive evidence is still lacking. In this study we investigated gene expression modifications induced in human colon tissue in relation to NOC exposure to gain insight in the relevance of these compounds in human colorectal cancer (CRC) development. Since there are indications that inflammation stimulates endogenous NOC formation, the study population consisted of patients with inflammatory bowel disease (IBD) and irritable bowel syndrome patients as controls without inflammation. Strong transcriptomic differences were identified in colonic biopsies from IBD patients and compared to controls that enhance the understanding of IBD pathophysiology. However, fecal NOC levels were not increased in IBD patients, suggesting that inflammation did not stimulate NOC formation. By relating gene expression changes of all subjects to fecal NOC levels, we did, however, identify a NOC exposure-associated transcriptomic response that suggests that physiological NOC concentrations may induce genotoxic responses and chromatin modifications in human colon tissue, both of which are linked to carcinogenicity. In a network analysis, chromatin modifications were linked to 11 significantly modulated histone genes, pointing towards a possible epigenetic mechanism that may be relevant in comprehending the molecular basis of NOC-induced carcinogenesis. We conclude that NOC exposure is associated with gene expression modifications in the colon that may increase CRC risk in humans. Study 2: Red meat intake-induced increases in fecal water genotoxicity correlate with pro-carcinogenic gene expression changes in the human colon Study 2: Red meat consumption is associated with an increased colorectal cancer (CRC) risk, which may be due to an increased endogenous formation of genotoxic N-nitroso compounds (NOCs). To assess the impact of red meat intake on potential risk factors of CRC, we investigated the effect of a 7-day dietary red meat intervention in human subjects on endogenous NOC formation and fecal water genotoxicity in relation to transcriptomic changes induced in colonic tissue. In order to evaluate the potential effect of an inflamed colon on endogenous nitrosation, the study population consisted of inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) control subjects without inflammation. The intervention had no effect on fecal NOC formation but fecal water genotoxicity significantly increased in response to red meat intake. Since IBD patients showed no difference in fecal NOC formation or fecal water genotoxicity levels as compared to IBS controls, for transcriptomic analyses, all subjects were grouped together. Genes significantly correlating with the increase in fecal water genotoxicity were involved in biological pathways indicative of genotoxic effects, including modifications in DNA damage, cell cycle, and apoptosis pathways. Moreover, WNT signaling and nucleosome remodeling pathways were modulated that are known to play a part in the carcinogenic process in the human colon. These results are in line with a possible oxidative effect of dietary heme. We conclude that the gene expression changes identified in this study corroborate the genotoxic potential of diets high in red meat and point towards a possible risk of CRC development in humans. The study investigated transcription levels in human colon biopsies obtained during a colonoscopic exam in 32 subjects suffering from either inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS). IBS patients served as control patients for comparison with IBD patients (see Study 1). 12 of these patients (6 IBD and 6 IBS) also followed a 7-day diet high in red meat (300 grams/day) after which a second colonscopic exam was performed to obtain colon biopsies to investigate the effect of the red meat intervention (Study 2). For each subject, cRNA copies of mRNA isolated from the colon biopsies were labeled with one dye (Cy3) and each sample was hybridized on a separate array. One replicate per subject or before/after red meat intervention (so 44 arrays in total, i.e. 20 before patients and 12 before and after patients).