Project description:Treatment of severely refractory Crohn’s disease (CD) patients remains a clinical challenge. Recent studies show the efficacy of autologous hematopoietic stem cell transplant (HSCT) in these severely compromised patients. HSCT is thought to eliminate auto-reactive cells; however, no specific studies of immune reconstitution in CD patients are available. We studied a group of CD patients receiving autologous HSCT, with 50% of them achieving endoscopic drug-free remission. To elucidate the mechanism driving efficacy, we studied changes in the immune cell composition in tissue induced by HSCT.
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:The interpretation of transcriptional profiling studies of intestinal tissue from Crohn’s disease patients and control patients can be confounded by differing proportions of cell subsets (e.g. immune cells) present in these samples. In this study, we aimed to control for cellular composition using standard, archival formalin-fixed, paraffin-embedded (FFPE) tissue specimens from Crohn’s patients (n=36) and controls (n=32) who underwent intestinal resection surgery. This approach allowed us to use the same tissue specimens for histological screening to select study samples with similar cellular composition and for RNA extraction for RNA-seq transcriptional profiling. We hypothesized that this approach would allow us to more clearly identify molecular signatures in ileal tissue that were associated with Crohn’s disease-associated pathological mechanisms.
Project description:Instability in the composition of gut bacterial communities, referred as dysbiosis, has been associated with important human intestinal disorders such as Crohn’s disease and colorectal cancer. Here, we show that dysbiosis coupled to Nod2 or Rip2 deficiency suffices to cause an increased risk for intestinal inflammation and colitis-associated carcinogenesis in mice. Aggravated epithelial lesions and dysplasia upon chemical-induced injury associated with loss of Nod2 or Rip2 can be prevented by antibiotics or anti-IL6R treatment. Nod2-mediated risk for intestinal inflammation and colitis-associated tumorigenesis is communicable through maternally-transmitted microbiota even to wild-type hosts. Disease progression was identified to drive complex NOD2-dependent changes of the colonic-associated microbiota. Reciprocal microbiota transplantation rescues the vulnerability of Nod2-deficient mice to colonic injury. Altogether, our results unveil an unexpected function for NOD2 in shaping a protective assembly of gut microbial communities, providing a rationale for intentional manipulation of genotype-dependent dysbiosis as a causative therapeutic principle in chronic intestinal inflammation.
Project description:Purpose: IBD diagnosis correlation with failure to achieve corticosteroid-free durable remission upon anti-TNF therapy Results: Enrichment of the GIMATS module (unique cellular signature found in a small cohort of surgically resected iCD ileums by scRNAseq) was also present in early stages of disease, prior to any biological therapy Conclusion: Confirmed the presence of the GIMATS module in bulk expression dataset and revealed that the presence of the module at diagnosis is associated with failure to achieve durable corticosteroid-free remission upon anti-TNF therapy in a pediatric inception cohort
Project description:Objective: The clinical presentation and course of Crohn’s disease (CD) is highly variable. We sought to better understand the cellular and molecular mechanisms that guide this heterogeneity, and characterize the cellular processes associated with disease phenotypes. Design: We examined both gene expression and gene regulation (chromatin accessibility) in non-inflamed colon tissue from a cohort of adult CD and control patients. To support the generality of our findings, we analyzed previously published expression data from a large cohort of treatment-naïve pediatric CD and control ileum. Results: We found that adult CD patients clearly segregated into two classes based on colon tissue gene expression—one that largely resembled the normal colon and one where certain genes showed expression patterns normally specific to the ileum. These classes were supported by changes in gene regulatory profiles observed at the level of chromatin accessibility, reflective of a fundamental shift in underlying molecular phenotypes. Further, gene expression from the ilea of the treatment-naïve pediatric CD patient cohort could be similarly subdivided into colon- and ileum-like classes. Finally, expression patterns within these CD subclasses highlight large-scale differences in the immune response and aspects of cellular metabolism, and were associated with multiple clinical phenotypes describing disease behavior, including rectal and perianal disease and need for colectomy. Conclusion: Our results strongly suggest that these molecular signatures define two clinically relevant forms of CD irrespective of tissue sampling location, patient age or treatment status.
Project description:Instability in the composition of gut bacterial communities, referred as dysbiosis, has been associated with important human intestinal disorders such as Crohn’s disease and colorectal cancer. Our data showed that Nod2-mediated risk of intestinal inflammation in colitis model is communicable to WT mice by cohousing. Here, we investigated if Nod2-deficient mice microbiota is able to change transcript profiles in Nod2-immunocompetent mice (C57Bl6/J mice) independently of colitis. Analysis used RNA extracted from colonic mucosa of C57Bl/6J mice co-housed with Nod2-deficient mice and C57Bl/6J mice alone. Direct comparisons of 4 biologicals replicates of C57Bl/6J mice cohoused with Nod2-deficient mice vs C57Bl/6J mice were performed.
Project description:Intestinal microbial dysbiosis is associated with Crohn’s disease (CD). However, the mechanisms leading to the chronic mucosal inflammation that characterizes this disease remain unclear. To evaluate causality and mechanisms of disease, we conducted a systems level study of the interactions between the gut microbiota and host in new-onset pediatric patients. We report an altered host proteome in CD patients indicative of impaired mitochondrial functions. A downregulation of mitochondrial proteins implicated in H2S detoxification was observed, while the relative abundance of H2S microbial producers was increased. Network correlation analysis identified Atopobium parvulum as the central hub of H2S producers. Gnotobiotic and conventionalized colitis-susceptible interleukin-10-deficient (Il10-/-) mice demonstrated that A. parvulum induced colitis, a phenotype requiring the presence of the intestinal microbiota. Administration of bismuth, a H2S scavenger, prevented A. parvulum-induced colitis in Il10-/- mice. This study identified host-microbiota interactions that are disturbed in CD patients providing mechanistic insights on CD pathogenesis.
Project description:Instability in the composition of gut bacterial communities, referred as dysbiosis, has been associated with important human intestinal disorders such as Crohn’s disease and colorectal cancer. Our data showed that Nod2-mediated risk of intestinal inflammation in colitis model is communicable to WT mice by cohousing. Here, we investigated if Nod2-deficient mice microbiota is able to change transcript profiles in Nod2-immunocompetent mice (C57Bl6/J mice) independently of colitis.