EQTL in diseased colon tissue identifies novel target genes associated with IBD
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PROVIDER: PRJNA1171826 | ENA |
REPOSITORIES: ENA
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Project description:Genome-wide association studies (GWAS) have identified over 300 loci associated with the inflammatory bowel diseases (IBD), but putative causal genes for most are unknown. We conducted the largest disease-focused expression quantitative trait loci (eQTL) analysis using colon tissue from 252 IBD patients to determine genetic effects on gene expression and potential contribution to IBD. Combined with two non-IBD colon eQTL studies, we identified 194 potential target genes for 108 GWAS loci. eQTL in IBD tissue were enriched for IBD GWAS loci colocalizations, provided novel evidence for IBD-associated genes such as ABO and TNFRSF14, and identified additional target genes compared to non-IBD tissue eQTL. IBD-associated eQTL unique to diseased tissue had distinct regulatory and functional characteristics with increased effect sizes. Together, these highlight the importance of eQTL studies in diseased tissue for understanding functional consequences of genetic variants, and elucidating molecular mechanisms and regulation of key genes involved in IBD.
2024-10-16 | GSE279302 | GEO
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).
2011-02-01 | E-GEOD-25220 | biostudies-arrayexpress
Project description:Genome wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) associated with diseases of the colon including inflammatory bowel diseases (IBD) and colorectal cancer (CRC). However, the functional role of many of these SNPs is largely unknown and tissue-specific resources are lacking. Expression quantitative trait loci (eQTL) mapping identifies target genes of disease-associated SNPs. Here, we comprehensively map eQTLs in the human colon, assess their relevance for GWAS of colonic diseases and provide functional characterization.
2014-04-15 | GSE56789 | GEO
Project description:The study aims to investigate the differences between Human intestinal blood and lymphatic endothelial cells, HIBECs and HILECs, respectively, isolated from colon and ilea of IBD and control patients.
2021-12-21 | GSE191234 | GEO
Project description:Colon gene expression in human IBD. The three major clinical subsets of Inflammatory Bowel Disease (IBD) include colon-only Crohn's Disease (CD), ileo-colonic CD, and Ulcerative Colitis (UC). These experiments tested differential colon gene expression in these three types of IBD, relative to healthy control samples, and the local degree of mucosal inflammation as measured by the CD Histological Index of Severity (CDHIS). Colon biopsy samples were obtained from IBD patients at diagnosis and during therapy, and healthy controls. The global pattern of gene expression was determined using GeneSpring software, with a focus upon candidate genes identified in a recent genome wide association study in pediatric onset IBD. Data suggested that two of these candidate genes are up regulated in pediatric IBD, partially influenced by local mucosal inflammation. These experiments tested differential colon gene expression in healthy, CD, and UC samples for candidate genes identified in a recent pediatric onset IBD genome wide association study. Keywords: Single time point in CD and UC and healthy controls.
2009-03-11 | GSE10616 | GEO
Project description:Colon gene expression in human IBD. The three major clinical subsets of Inflammatory Bowel Disease (IBD) include colon-only Crohn's Disease (CD), ileo-colonic CD, and Ulcerative Colitis (UC). These experiments tested differential colon gene expression in these three types of IBD, relative to healthy control samples, and the local degree of mucosal inflammation as measured by the CD Histological Index of Severity (CDHIS). Colon biopsy samples were obtained from IBD patients at diagnosis and during therapy, and healthy controls. The global pattern of gene expression was determined using GeneSpring software, with a focus upon candidate genes identified in a recent genome wide association study in pediatric onset IBD. Data suggested that two of these candidate genes are up regulated in pediatric IBD, partially influenced by local mucosal inflammation. These experiments tested differential colon gene expression in healthy, CD, and UC samples for candidate genes identified in a recent pediatric onset IBD genome wide association study. Keywords: Single time point in CD and UC and healthy controls. Colon RNA was isolated from biopsies obtained from CD and UC at diagnosis and during therapy and healthy controls. Samples were obtained from the most proximal affected segment of colon. Microarray experiments were performed as described in the CCHMC microarray core, and data was analyzed as described above in the summary. The '107' internal control CEL files (for batches 1,2,3,4,5) used for normalization of the Sample VALUEs are also contained within this data set.
2009-03-10 | E-GEOD-10616 | biostudies-arrayexpress
Project description:'Illumina Infinium HumanMethylation450 BeadChip data from CD326+ sorted colonic epithelial cells of mucosal biopsies from treatment-naive paediatric IBD patients (Crohn''s Disease or Ulcerative Colitis) or age-matched controls AC= ascending colon, PSC=sigmoid colon'
2015-09-15 | E-MTAB-3709 | biostudies-arrayexpress
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.
2011-02-01 | GSE25220 | GEO
Project description:With a greater understanding of the genetic risk variants associated with inflammatory bowel disease, there is a need to prioritize candidate genes within risk loci leading to the disease-SNP association. We created a custom NanoString probeset to capture 678 genes of interest in IBD (including 440 genes encoded within IBD risk loci and 15 housekeeping genes) - 22% of genes were not captured on traditional microarray platforms. Total RNA extracted from terminal ileum and colon tissues (uninflamed and inflamed) was used from patients with Crohn's disease and ulcerative colitis and healthy controls. We studied differential expression and performed an eQTL analysis to prioritize candidate genes within the risk loci.
2016-08-10 | GSE73094 | GEO
Project description:Genome wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) associated with diseases of the colon including inflammatory bowel diseases (IBD) and colorectal cancer (CRC). However, the functional role of many of these SNPs is largely unknown and tissue-specific resources are lacking. Expression quantitative trait loci (eQTL) mapping identifies target genes of disease-associated SNPs. Here, we comprehensively map eQTLs in the human colon, assess their relevance for GWAS of colonic diseases and provide functional characterization. Subjects included 40 healthy African American individuals who had undergone colonoscopy at the University of Illinois Chicago for screening purposes. Distal colonic biopsies were obtained in all subjects at 20 cm from the anal verge at the recto-sigmoid junction and were immediately dispensed in RNAlater. Total mRNA was extracted from manually ground tissue with the Promega Maxwell 16 Tissue LEV Total RNA Purification Kit for automated purification on the Maxwell 16 Instrument and mRNA analysis was performed on Illumina HumanHT-12v4 Expression BeadChip arrays. Genomic DNA was obtained from whole-blood samples from the same individuals and genotyped using the Affymetrix Axiom Genome-wide Pan-African array. Cis- and trans-eQTL analyses were performed on the dataset of 8.4 million imputed SNPs and 16,252 expression probes corresponding to 12,363 unique autosomal genes in 40 subjects. Associations between SNPs and gene expression levels were examined with Matrix eQTL using linear regression. False discovery rate calculations were performed separately for cis- and trans-eQTLs.
2014-04-15 | E-GEOD-56789 | biostudies-arrayexpress