Project description:Previously, we conducted an epigenome-wide study of DNA methylation (~850K sites) in peripheral blood at diagnosis and during follow-up from the RISK pediatric Crohn’s disease inception cohort and data are deposited in GEO with an access number GSE112611. We further followed up this study and identified here the genetic influence on ~850K DNAm sites (mQTL) in peripheral blood as well as newly added 41 ileal biopsies. All the ileal biopsies DNAm data are collected from the subset of primary 238 pediatric CD cohort that contains the peripheral blood DNAm data in GSE112611. Comparing the mQTL effect sizes among 164 CD cases at baseline, 164 CD cases at 3 years follow-up, 74 healthy controls and 41 ileal biopsies confirms that genetic influence on DNAm sites are strongly consistent among these groups. This study further concludes that the mQTLs are largely not disease-specific or inflammation-specific or tissue-specific.
Project description:We report the global pattern of ileal gene expression in a cohort of 310 treatment-naïve pediatric Crohn Disease patients and controls. We focus on genes with consistent altered expression in the ileum of younger (Paris age A1a) vs older (Paris age A1b) patients.
Project description:Microbial dysbiosis has been identified in adult inflammatory bowel disease (IBD) patients. However, microbial composition and functional interplay between host genetics and microorganisms in early IBD onset remain poorly defined. Here, we identified and demonstrated the causal effect of Atopobium parvulum and the gut microbiota in pediatric IBD. Microbiota and proteomic profiling revealed that the abundance of A. parvulum, a potent H2S producer, was associated with increased disease severity and a concurrent reduction in the expression of the host H2S detoxification pathway. In the Il10-/- mouse model of inflammation, A. parvulum induced severe pancolitis that was dependent on the presence of the gut microbiota. In addition, we demonstrated that administration of bismuth, an H2S scavenger, prevented A. parvulum-induced colitis. Our findings identified Atopobium parvulum as a major mediator of inflammation severity, and revealed an alteration of the balance between the production and detoxification of H2S in the gastrointestinal tract.
Project description:Inflammatory Bowel Diseases are associated with marked alterations of IECs with a subsequent loss of barrier function. To identify alterations in signaling pathways in intestinal epithelium upon inflammation, we analyzed the transcriptome of IECs from patients suffering from Crohn’s disease.
Project description:The course of Crohn's disease (CD) is heterogeneous, confounding effective personalized therapy. A previous analysis of differences in gene expression between patients with versus without CD groups revealed 2 subsets of patients with CD -- a group characterized by genes more highly expressed in the colon (colon-like CD) and a group with increased expression of ileum marker genes (ileum-like CD). We compared differences in microRNAs between these groups. We performed genome-wide microRNA profile analyses of colon tissues from 18 adults with CD and 12 adults without CD (controls). We performed principal component analyses to associate levels of microRNAs with CD subtypes. Colonic epithelial cells and lamina propria immune cells were isolated from intestinal tissues and levels of microRNA 31 (miR-31) were measured by real-time quantitative PCR. We validated the differential expression of miR-31 between the subtypes by measuring miR-31 levels in an independent cohort of 32 adult patients with CD and 23 controls. We generated epithelial colonoid cultures from controls and patients with CD, and measured levels of miR-31 in crypts. We performed genome-wide microRNA profile analyses of formalin-fixed paraffin-embedded colon and ileum biopsies from 76 treatment-naive pediatric patients with CD and 51 controls (234 samples) and collected data on disease features and outcomes. In comparing miRNA expression profiles between 9 patients with colon-like CD and 9 patients with ileum-like CD, we identified 19 miRNAs with significant differences in levels. We observed a 13.5-fold difference in level of miR-31-5p between tissues from patients with colon-like vs. ileum-like CD (Padj = 1.43 x 10-18). Principal component analysis found miR-31 to be the top contributor to the variance observed. Levels of miR-31 were increased 60-fold in tissues from patients with ileum-like CD compared with controls (Padj = 2.59 × 10-51). We validated the differential expression of miR-31 between the subtypes in the independent set of tissues. Colonoids derived from patients with CD had significantly higher levels of miR-31 than colonoids derived from control tissues (day 2 P=.041 and day 6 P=.0095). Levels of miR-31 were significantly increased in colon tissues from pediatric patients with CD compared with controls (~7.8-fold, P=4.64 ×10-7) and in ileum tissues from patients with CD patients vs. controls (~1.5-fold, P=9.97 × 10-7). A high level of miR-31 in index biopsies from pediatric patients with only inflammation and no other complications at time of diagnosis associated with development of fibrostenotic ileal CD. We identified differences in miR-31 levels in colon tissues from adult and pediatric patients with CD compared with controls, and in patients with ileum-like CD compared with colon-like CD. Further studies are needed to determine the mechanisms by which miR-31 might contribute to pathogenesis of this subtype of CD, or affect response to therapy.
Project description:Crohn’s disease (CD) and ulcerative colitis are chronic inflammatory bowel diseases (IBD) of which the etiology and pathogenesis are not completely understood. In paediatric patients, the disease tends to be more severe and aggressive then in adults. Here, we perform a proteomic approach on ascending colon biopsies from 119 pediatric patients to characterize disease pathogenesis and the impacts of treatment. Consistent with previous findings, we report an altered proteome in IBD patients that indicates impaired mitochondrial function. Gene ontology revealed that proteins downregulated in inflammation are associated with metabolism, whereas upregulated proteins contribute to protein processing. A comparison of proteomes from CD patients before and after therapeutic intervention identified over 100 proteins that are significantly different between patients that responded and those that did not respond to therapy; creatine kinase B was elevated before treatment in patients with mucosal healing after treatment, whereas basigin increased after treatment in responsive patients.
Project description:Crohn’s disease is a relapsing inflammatory disorder with a variable clinical course. While most patients present with purely an inflammatory phenotype (B1) at diagnosis, a subgroup (~20%) rapidly progresses to complicated disease manifestations that include stricturing (B2) within 5 years. DNA methylation is a key epigenetic mechanism that can regulate gene expression and thereby influence the development and progression of complex diseases. Site-specific DNA methylation differences have been reported in peripheral blood of patients with Crohn’s disease, but investigation of the temporal relationship between methylation and disease is required to establish whether the methylome plays a causal role and can be leveraged for therapeutic benefits. To this end, we conducted an epigenome-wide study of methylation (~850K sites) in peripheral blood at diagnosis and during follow-up from the RISK pediatric Crohn’s disease inception cohort. While some methylation changes associated with Crohn’s disease might be causal, in peripheral blood the vast majority are found to be a transient consequence of inflammation and thus a symptom of disease.
Project description:Background/Aims: Cholestatic liver diseases (CLD) are the leading indication for pediatric liver transplantation. Increased intrahepatic bile acid concentrations cause endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) is activated to maintain homeostasis. UPR dysregulation, including the inositol-requiring enzyme 1α/X-box protein 1 (IRE1α/XBP1) pathway, is associated with several adult liver diseases. We evaluated hepatic UPR expression in pediatric patients with end-stage CLD and hypothesize that an inability to appropriately activate the hepatic IRE1α/XBP1 pathway is associated with the pathogenesis of CLD. Methods: We evaluated 34 human liver explants. Cohorts included: pediatric CLD (Alagille, ALGS, and progressive familial intrahepatic cholestasis, PFIC), pediatric non-cholestatic liver disease controls (autoimmune hepatitis, AIH), adult CLD, and normal controls. We performed RNA-seq, quantitative PCR, and western blotting to measure expression differences of the hepatic UPR and other signaling pathways. Results: Metascape pathway analysis demonstrated that the KEGG ‘protein processing in ER’ pathway was downregulated in pediatric CLD compared to normal controls. Pediatric CLD had decreased hepatic IRE1α/XBP1 pathway gene expression and decreased protein expression of p-IRE1α compared to normal controls. These CLD changes were not disease-specific to ALGS or PFIC. IRE1α/XBP1 pathway gene expression was decreased in pediatric CLD compared to AIH disease controls. Conclusion: Pediatric CLD explants have decreased gene and protein expression of the protective IRE1α/XBP1 pathway and down-regulated KEGG protein processing in the ER pathways. IRE1α/XBP1 pathway expression differences occur when compared to both normal and non-cholestatic disease controls. Attenuated expression of the IRE1α/XBP1 pathway is associated with cholestatic diseases and could be targeted to treat pediatric CLD.