Project description:Primary sclerosing cholangitis (PSC) is an autoimmune-like disease of the bile ducts that co-occurs with inflammatory bowel disease (IBD) in almost 90% of cases. Colorectal cancer is a major complication of patients with both PSC and IBD, and these patients are at a much greater risk compared to patients with IBD without concomitant PSC. Combining flow cytometry, bulk and single cell transcriptomics, and T- and B-cell receptor repertoire analysis of right colon tissue from PSC, IBD, and healthy controls we identified a unique adaptive inflammatory transcriptional signature associated with greater risk and shorter time to dysplasia specifically in patients with PSC. This inflammatory signature is characterized by antigen-driven IL-17A+ Foxp3+ CD4 T-cell and an expansion of IgG-secreting B-cell responses. These data results suggest that the mechanisms that drive the emergence of dysplasia in of PSC and IBD dysplasia are distinct and provide molecular insights to guide prevention of colorectal cancer in PSC.
Project description:Primary sclerosing cholangitis (PSC) is an autoimmune-like disease of the bile ducts that co-occurs with inflammatory bowel disease (IBD) in almost 90% of cases. Colorectal cancer is a major complication of patients with both PSC and IBD, and these patients are at a much greater risk compared to patients with IBD without concomitant PSC. Combining flow cytometry, bulk and single cell transcriptomics, and T- and B-cell receptor repertoire analysis of right colon tissue from PSC, IBD, and healthy controls we identified a unique adaptive inflammatory transcriptional signature associated with greater risk and shorter time to dysplasia specifically in patients with PSC. This inflammatory signature is characterized by antigen-driven IL-17A+ Foxp3+ CD4 T-cell and an expansion of IgG-secreting B-cell responses. These data results suggest that the mechanisms that drive the emergence of dysplasia in of PSC and IBD dysplasia are distinct and provide molecular insights to guide prevention of colorectal cancer in PSC.
Project description:Patients with both primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) run a 10-fold increased risk of developing colorectal carcinoma (CRC) compared to patients with IBD only. It is unknown which mucosal defects are causing this increased risk. The aim of this study was to investigate which molecular changes give rise to CRC in patients with PSC-IBD, and whether changes occur already in non-dysplastic mucosa.
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:Inflammatory bowel disease (IBD) is associated with altered microbiota composition and metabolism, but it is unclear whether these changes precede inflammation or are the result of it since current studies have mainly focused on changes after the onset of disease. We previously showed differences in mucus gut microbiota composition preceded colitis-induced inflammation and stool microbial differences only became apparent at colitis onset. In the present study, we aimed to investigate whether microbial dysbiosis was associated with differences in both predicted microbial gene content and endogenous metabolite profiles. We examined the functional potential of mucus and stool microbial communities in the mdr1a -/- mouse model of colitis and littermate controls using PICRUSt on 16S rRNA sequencing data. Our findings indicate that despite changes in microbial composition, microbial functional pathways were stable before and during the development of mucosal inflammation. LC-MS-based metabolic phenotyping (metabotyping) in urine samples confirmed that metabolite profiles in mdr1a -/- mice were remarkably unaffected by development of intestinal inflammation and there were no differences in previously published metabolic markers of IBD. Metabolic profiles did, however, discriminate the colitis-prone mdr1a -/- genotype from controls. Our results indicate resilience of the metabolic network irrespective of inflammation. Importantly as metabolites differentiated genotype, genotype-differentiating metabolites could potentially predict IBD risk.