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).
Project description:A subset of post-infection irritable bowel syndrome (PI-IBS) patients have elevated, or high fecal proteolytic activity (PA). Fecal PA has been shown to correlate with increased symptom severity as well as lower quality of life scores, increased fecal output and increased intestinal permeability. To address the underlying mechanisms of barrier disruption as a consequence of high fecal PA, colonic biopsies were collected from healthy individuals PI-IBS patients (n=11). Individuals diagnosed with PI-IBS were further divided in to 2 subgroups, high PA and low PA as defined by the PA in matched fecal samples. RNA was extracted from the biopsies for bulk RNA sequencing to understand transcriptional differences between healthy and high PA PI-IBS patients as well as high PA and Low PA PI-IBS patients.
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.
Project description:Deficiency in the X-linked inhibitor of apoptosis protein (XIAP) is the cause for the X-linked lymphoproliferative syndrome 2 (XLP2). About one third of all patients suffers from severe and therapy refractory inflammatory bowel disease (IBD), but the exact pathogenesis remains undefined. We examined the differences in gene expression of pediatric XLP2 patients with IBD to healthy controls and pediatric IBD patients.
2021-09-20 | GSE183069 | GEO
Project description:fecal metagenomes of irritable bowel syndrome patients
Project description:Compromise of the intestinal barrier have been associated with a series of inflammatory conditions where the routine controls nutrient absorption and pathogens exclusion is lost to different degrees. The intestinal epithelial cells form a barrier of selective permeability which protects from invasion by the normal bacteria present in the gut. When the barrier is compromised, bacteria and their products can attack the cells and cause inflammation, which can (in severe cases) cause sepsis. Mesenteric lymph nodes play a crucial role in the immune response and are of particular importance in the study of Inflammatory Bowel Disease (IBD) patients due to their involvement in the disease process. To assess the efficiency of gut immune barrier, we collected the pre-nodal lymph from Inflammatory Bowel Disease (IBD) subjects and performed a comprehensive proteomic analysis. The current study is complementary extension of the proteomics signature found in DSS-induced colitis mouse model, providing an insight in the lymph composition, and associated biochemical changes, in the set of samples (n=6) recruited from the Inflammatory Bowel Disease (IBD), subjects undergoing intestinal resection. Following bottom-up analysis, the enrichment analysis – GO and Ingenuity pathway analysis (IPA) analysis identified several pathways pointing towards a damaging phenotype.
Project description:Increased numbers of mast cells and their products have been linked to symptom onset and severity in patients with chronic diarrhea and abdominal pain. Although mast-cell inhibition ameliorates clinical manifestations and reduces mucosal inflammation, underlying molecular mechanisms remain unknown. Experiment Overall Design: Diarrhea-irritable bowel syndrome (d-IBS) patients were studied at baseline, or 6 months after natural evolution (control) or oral cromoglycate treatment. Jejunal biopsies were subjected to chip analysis (Affymetrix Human Genome U133 Plus 2.0 GeneChips).