ABSTRACT: We aim to whole-exome sequence DNA samples from 75 individuals with severe forms of Inflammatory Bowel Disease and related autoimmune diseases to identify the rare, highly penetrant, variants that we believe underlie these phenotypes. Case samples will be obtained from both new and existing (UK IBD Genetics Consortium) collaborators to ensure only the most extreme cases are sequenced.
Project description:We aim to whole-exome sequence DNA samples from 75 individuals with severe forms of Inflammatory Bowel Disease and related autoimmune diseases to identify the rare, highly penetrant, variants that we believe underlie these phenotypes. Case samples will be obtained from both new and existing (UK IBD Genetics Consortium) collaborators to ensure only the most extreme cases are sequenced.
Project description:Inflammatory bowel disease (IBD) is heritable, but a total of 163 variants commonly implicated in IBD pathogenesis account for only 25% of the heritability. Rare, highly penetrant genetic variants may also explain mendelian forms of IBD and some of the missing heritability. To test the hypothesis that rare loss-of-function mutations can be causative, we performed whole exome sequencing (WES) on 5 members of a 2-generation family of European ancestry presenting with an early-onset and atypical form of IBD.WES was performed for all of the 5 family members; the mother and 3 male offspring were affected, whereas the father was unaffected. Mapping, annotation, and filtering criteria were used to reduce candidate variants. For functional testing we performed forkhead box P3 (FOXP3) staining and a T-cell suppression assay.We identified a novel missense variant in exon 6 of the X-linked FOXP3 gene. The c.694A>C substitution in FOXP3 results in a cysteine-to-glycine change at the protein position 232 that is completely conserved among all vertebrates. This variant (heterozygous in the mother and hemizygous in all 3 affected sons) did not impair FOXP3 protein expression, but significantly reduced the ability of the host's T regulatory cells to suppress an inappropriate autoimmune response. The variant results in a milder immune dysregulation, polyendocrinopathy, enteropathy, and X-linked phenotype with early-onset IBD.Our study illustrates the successful application of WES for making a definitive molecular diagnosis in a case of multiply affected families, with atypical IBD-like phenotype. Our results also have important implications for disease biology and disease-directed therapeutic development.
Project description:Chronic inflammation is commonly present in gastrointestinal mucosal sites at increased risk for cancer, such as in inflammatory bowel disease (IBD) or chronic gastritis caused by Helicobacter pylori infection. Why some patients have more mucosal inflammation than others, and why certain individuals with chronic inflammation develop cancer, are problems that have not been solved. Unlike the case for the syndromic forms of familial colorectal cancer (CRC), the risks for IBD and other forms of chronic inflammation have not been linked to highly penetrant single gene mutations. Single nucleotide polymorphisms (SNP) are variations in DNA sequence that can be linked to any phenotype (cancer, chronic inflammation, etc.) in genome-wide association studies (GWAS). CRC has been linked to several highly penetrant single gene loci, as well as multiple SNP. The propensity to develop IBD has not been linked to single gene mutations in most instances, but has been linked to SNP in the NOD2 locus (which appear to create hypomorphic alleles for this bacterial response gene), the IL23R locus, the autophagy gene ATG16L1 and a wide range of other loci including the Toll-like receptors, JAK2 and STAT3, and perhaps 70 more. At present, the problem in predicting risk for chronic inflammation is that there are many genetic polymorphisms with relatively modest individual effects. Our challenge is to understand how the SNPs that are linked to variations in the inflammatory response interact with one another (i.e. to understand the 'epistasis' involved), and to integrate this with the variety of individual environmental exposures. This represents an opportunity for informatics science to help personalize our approach to chronic inflammatory diseases of the gut and identify those at greatest risk for cancer.
Project description:TNF-like ligand 1A (TL1A), which binds its cognate receptor DR3 and the decoy receptor DcR3, is an identified member of the TNF superfamily. TL1A exerts pleiotropic effects on cell proliferation, activation, and differentiation of immune cells, including helper T cells and regulatory T cells. TL1A and its two receptors expression is increased in both serum and inflamed tissues in autoimmune diseases such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and ankylosing spondylitis (AS). Polymorphisms of the TNFSF15 gene that encodes TL1A are associated with the pathogenesis of irritable bowel syndrome, leprosy, and autoimmune diseases, including IBD, AS, and primary biliary cirrhosis (PBC). In mice, blocking of TL1A-DR3 interaction by either antagonistic antibodies or deletion of the DR3 gene attenuates the severity of multiple autoimmune diseases, whereas sustained TL1A expression on T cells or dendritic cells induces IL-13-dependent small intestinal inflammation. This suggests that modulation of TL1A-DR3 interaction may be a potential therapeutic target in several autoimmune diseases, including IBD, RA, AS, and PBC.
Project description:BACKGROUND:Intestinal barrier defects are common in patients with inflammatory bowel disease (IBD). To identify which components could underlie these changes, we performed an in-depth analysis of epithelial barrier genes in IBD. METHODS:A set of 128 intestinal barrier genes was selected. Polygenic risk scores were generated based on selected barrier gene variants that were associated with Crohn's disease (CD) or ulcerative colitis (UC) in our study. Gene expression was analyzed using microarray and quantitative reverse transcription polymerase chain reaction. Influence of barrier gene variants on expression was studied by cis-expression quantitative trait loci mapping and comparing patients with low- and high-risk scores. RESULTS:Barrier risk scores were significantly higher in patients with IBD than controls. At single-gene level, the associated barrier single-nucleotide polymorphisms were most significantly enriched in PTGER4 for CD and HNF4A for UC. As a group, the regulating proteins were most enriched for CD and UC. Expression analysis showed that many epithelial barrier genes were significantly dysregulated in active CD and UC, with overrepresentation of mucus layer genes. In uninflamed CD ileum and IBD colon, most barrier gene levels restored to normal, except for MUC1 and MUC4 that remained persistently increased compared with controls. Expression levels did not depend on cis-regulatory variants nor combined genetic risk. CONCLUSIONS:We found genetic and transcriptomic dysregulations of key epithelial barrier genes and components in IBD. Of these, we believe that mucus genes, in particular MUC1 and MUC4, play an essential role in the pathogenesis of IBD and could represent interesting targets for treatment.
Project description:Background:Prior studies suggest dietary modification may improve clinical response or remission rates in patients with inflammatory bowel disease (IBD). Our aim was to examine whether an autoimmune protocol diet improves quality of life in patients with active Crohn disease (CD) and ulcerative colitis (UC). Methods:We conducted an uncontrolled clinical trial of the autoimmune protocol diet in adult patients with active IBD (Harvey-Bradshaw Index ? 5 for CD or partial Mayo score ? 3 for UC, and erosions/ulcers on endoscopy and/or elevated fecal calprotectin). The dietary intervention consisted of a 6-week elimination phase, followed by a 5-week maintenance phase. Short Inflammatory Bowel Disease Questionnaire (SIBDQ) was completed at baseline, and weeks 3, 6, 9, and 11. Results:The final cohort included 6 UC and 9 CD participants. Mean SIBDQ score improved significantly from baseline (46.5) to weeks 3 (54.0, P = 0.02), 6 (53.3, P = 0.02), 9 (62.0, P = 0.03), and 11 (60.5, P = 0.05). Among participants completing all 5 surveys, mean SIBDQ increased from 46.5 to 61.5 by week 11 (P = 0.03). By week 3, participants experienced significant improvements in bowel movement frequency (36%, P = 0.04), stress (28%, P = 0.01), and ability to perform leisure/sport activities (29%, P = 0.02). Effects were not significantly different between CD and UC participants. Conclusions:Dietary modification can improve quality of life as early as week 3 in patients with active IBD. Larger randomized controlled trials are needed to examine dietary interventions in IBD.
Project description:MicroRNAs (miRNAs) are small, noncoding RNAs that regulate gene and protein expression. miRNAs are critical to a normal immune response and have altered expression in multiple immune-mediated disorders. This emerging role of miRNAs in the pathogenesis of multiple disease states has led to investigations into miRNA expression profiles in inflammatory bowel disease (IBD). The discovery of miRNAs in IBD is likely to contribute to our understanding of IBD pathogenesis and lead to clinical advances in IBD. This review focuses on miRNA expression in inflammation, autoimmune disorders, and inflammation-associated cancer, as well as their function in the biology and management of IBD.
Project description:Cell-free nucleic acids (cfNAs) are defined as any nucleic acids that are present outside the cell. They represent valuable biomarkers in various diagnostic protocols such as prenatal diagnostics, the detection of cancer, and cardiovascular or autoimmune diseases. However, in the current literature, little is known about their implication in inflammatory bowel disease (IBD). IBD is a group of multifactorial, autoimmune, and debilitating diseases with increasing incidence worldwide. Despite extensive research, their etiology and exact pathogenesis is still unclear. Since cfNAs were observed in other autoimmune diseases and appear to be relevant in inflammatory processes, their role in the pathogenesis of IBD has also been suggested. This review provides a summary of knowledge from the available literature about cfDNA and cfRNA and the structures involving them such as exosomes and neutrophil extracellular traps and their association with IBD. Current studies showed the promise of cfNAs in the management of IBD not only as biomarkers distinguishing patients from healthy people and differentiating active from inactive disease state, but also as a potential therapeutic target. However, the detailed biological characteristics of cfNAs need to be fully elucidated in future experimental and clinical studies.
Project description:Crohn's disease (CD) is a debilitating inflammatory bowel disease (IBD), that, like all complex disorders, emerges on a background of many genetic and environmental factors. miRNAs can play an important role in the induction of autoimmune diseases and IBD. The aim of our study was to identify, besides the differentially expressed miRNAs, miRNAs with an altered activity on transcriptome in CD tissues as a consequence of the aforementioned modifications.
Project description:A20 haploinsufficiency (HA20), a disease caused by loss-of-function TNFAIP3 mutations, manifests various autoinflammatory and/or autoimmune symptoms. Some cases of HA20 were initially diagnosed as very early onset inflammatory bowel disease (VEO-IBD). We performed whole-exome sequencing (WES) for a Japanese girl with infantile-onset IBD and a severe perianal lesion and detected a novel de novo 119?kb microdeletion containing only TNFAIP3 (arr[GRCh37] 6q23.3(138125829_138244816)?×?1).