Project description:Perianal Fistulizing Crohn’s Disease (perianal-CD) is a debilitating form of CD typically associated with prolonged periods of morbidity. Leveraging single-cell RNA sequencing, rectal mucosal tissue was sequenced from individuals following anti-TNF biologic therapy having either active perianal-CD and inflamed rectal mucosa or healed perianal-CD but non-inflamed mucosa. Single cell transcriptomic profiles of the inflamed and non-inflamed tissue were contrasted to test for specific cellular subsets of rectal epithelial and immune cell compartments associated with inflamed perianal disease. We identified eight broad classes of epithelial, six of immune, and a small population of stromal cells in the rectal mucosa. There was an increase in colonocytes in the non-inflamed tissue compared to the inflamed tissue, and an increase of naïve b cells and plasma cells associated with inflamed tissue. The cell type proportions of immune cells, highlighted patient heterogeneity of cell type abundance and potential dysregulation of both the immune and epithelial compartment. We also note enrichment of IgG plasma cells in inflamed tissue of two donors and expansion of IgA plasma cells of non-inflamed tissue in two donors. Differential gene expression analysis of goblet cells revealed enrichment of inflammatory pathways, such as IL6 and interferon gamma signaling, in inflamed tissue. These inflammatory pathways might affect tight junctions between epithelial cells leading to increased permeability and potentially affect fistula formation. Our findings suggest dysregulation of crypt maturation during persistent inflammation and over-abundance of goblet cells and colonocyte precursors in inflamed tissue of perianal-CD.
Project description:Background and aims: Perianal fistulizing Crohn’s disease (CD) is severe and often more difficult to treat than luminal CD. Current therapeutics focusing solely on the immune system neither target epithelial and mesenchymal compartments nor consider genetic/epigenetic mechanisms, potentially missing causative aspects of the disease. Thus, the mucosal cells and organoids from a cohort of perianal fistulizing CD patients and controls with diverse genetic backgrounds were experimentally examined. Results: Overall, 140,503 mucosa and 77,044 organoid cells were sequenced. Inflamed perianal CD showed changes across the mucosal compartments (epithelium, immune, stromal), the most dramatic taking place in the epithelium. Epithelial changes occurring in the rectum of perianal CD patients associated with inflammation, gender, and ancestry, and were accompanied by a reduction in differentiated lineages. Organoids from the patient cohort retained both the gender- and ancestral-specific gene expression but did not overwhelmingly reflect their disease status. Organoids lacked bona fide differentiated lineages, but secretory pathways were promoted through PGE2-PTGER4 signaling and HDAC function. Conclusion: Epigenetic modifications are disrupted in the epithelium during inflammation and perianal fistulizing CD that affect the differentiation capacity of those cells, limiting their production/function and thus diminishing the ability of the patients’ mucosal tissue to heal. These epigenetic modifications appear to be modulated by crosstalk between the epithelial and mesenchymal cells, and thus might be leveraged therapeutically.
Project description:Crohn’s disease (CD) is a chronic inflammatory condition that can affect any part of the gastrointestinal tract. African ancestry (AA) populations have been substantially under-represented in genome-wide association studies (GWAS) of CD and inflammatory bowel disease (IBD), reflecting in part the lower prevalence of CD in AA compared to European ancestry (EA) populations. Importantly, CD complicated by perianal fistulae has been found to be more prevalent and severe in African-ancestry patients. Perianal fistulae arise from the distal rectal mucosa and can course to a cutaneous surface, resulting in highly morbid complications. Monoclonal antibodies against anti-TNF are the mainstay of treatment, but recurrence and secondary loss-of-response is common. In severe, uncontrolled cases, complete proctectomy is required. The intestine is unique among adult tissues in that under homeostasis, residential macrophages are continually replenished from recruited blood monocytes. In EA cohorts, we established that chronic monocyte cultures stimulated with NOD2 agonists result in aberrant myeloid-stromal differentiation stratified by risk allele carrier status. NOD2 risk alleles are not associated with perianal fistulae; African-American patients with CD do not carry them (except via recent European ancestry admixture). There is no direct association between known CD GWAS risk loci and the risk of developing perianal fistula. Here, we present direct ex-vivo, single cell multiomic analyses of colorectal tissues and perianal fistulous tracts in AA and EA cases to define mechanisms of perianal fistula development. We implicate myeloid-stromal crosstalk and define cell subtypes using single cell RNA (scRNASeq), ATAC sequencing, and chronic, unstimulated monocyte cultures. Transcription factor motifs and ATAC signals co-localized with fine-mapped GWAS loci provide insight to cell-specific and transcriptional network regulation.
Project description:Crohn’s disease (CD) is a chronic inflammatory condition that can affect any part of the gastrointestinal tract. African ancestry (AA) populations have been substantially under-represented in genome-wide association studies (GWAS) of CD and inflammatory bowel disease (IBD), reflecting in part the lower prevalence of CD in AA compared to European ancestry (EA) populations. Importantly, CD complicated by perianal fistulae has been found to be more prevalent and severe in African-ancestry patients. Perianal fistulae arise from the distal rectal mucosa and can course to a cutaneous surface, resulting in highly morbid complications. Monoclonal antibodies against anti-TNF are the mainstay of treatment, but recurrence and secondary loss-of-response is common. In severe, uncontrolled cases, complete proctectomy is required. The intestine is unique among adult tissues in that under homeostasis, residential macrophages are continually replenished from recruited blood monocytes. In EA cohorts, we established that chronic monocyte cultures stimulated with NOD2 agonists result in aberrant myeloid-stromal differentiation stratified by risk allele carrier status. NOD2 risk alleles are not associated with perianal fistulae; African-American patients with CD do not carry them (except via recent European ancestry admixture). There is no direct association between known CD GWAS risk loci and the risk of developing perianal fistula. Here, we present direct ex-vivo, single cell multiomic analyses of colorectal tissues and perianal fistulous tracts in AA and EA cases to define mechanisms of perianal fistula development. We implicate myeloid-stromal crosstalk and define cell subtypes using single cell RNA (scRNASeq), ATAC sequencing, and chronic, unstimulated monocyte cultures. Transcription factor motifs and ATAC signals co-localized with fine-mapped GWAS loci provide insight to cell-specific and transcriptional network regulation.
Project description:Background & Aims: Perianal fistulizing Crohn’s disease (PCD) is a common and debilitating complication with elusive pathophysiology. We examined biopsies from patients with PCD and related conditions using a multi-omics approach. Methods: Patients with PCD (n=24), CD without perianal disease (NPCD, n=10), and idiopathic perianal fistulas (IPF, or cryptoglandular fistulas, n=25) were recruited. Biopsies were taken from fistula tracts, fistula opening, and rectal mucosa during examination under anesthesia or colonoscopy. Single-cell RNA-sequencing (scRNA-seq), mass cytometry (CyTOF), spatial transcriptomics (ST), immunohistochemistry (IHC), and integrated analysis of published datasets were performed. Results: ScRNA-seq, CyTOF, and ST unraveled immune and non-immune cell compartments in PCD and IPF fistula tracts. PCD fistulas showed hyperactivated pathogenic pathways including interferon (IFN)G response, TNF signaling, and IL6-JAK-STAT3 in myeloid cells. Similarly, stromal cells from PCD fistulas exhibited elevated IFNG and TNF response, TNF signaling, and epithelial-mesenchymal transition (EMT). Further analysis revealed cellular modules associated with anti-TNF therapy in PCD patients. In addition to fistula tracts, intestinal cells from PCD patients also expressed greater levels of IFNG-responsive and EMT genes compared to CD patients without perianal disease. In addition, we showed that both fistula tracts and ileal mucosa from PCD patients harbored expanded IFNG+ Th17 cells, which expressed elevated inflammatory mediators. The findings were independently validated using ST and IHC. Conclusion: Multi-omics analysis revealed immune and nonimmune cell landscapes of PCD. and highlights the pathogenic role of hyperactivated IFNG signaling in both fistula tracts and luminal mucosa of patients with PCD. This study identified IFNG as a potential therapeutic target for PCD.
Project description:BACKGROUND AND AIMS: Perianal fistula represents one of the most important complications in Crohn’s Disease (CD). Epithelial-to-mesenchymal transition (EMT) has been demonstrated to play a major role in the pathogenesis, however the mechanisms driving EMT need to be clarified. Significant alterations in the tissue structural composition occur in the fistula, but how these changes promote EMT was not addressed. We aim to explore the relevance of TSG-6, a stabilizer of extracellular matrix, in the fistula pathogenesis. METHODS: Intestinal surgical specimens from perianal fistula tissue and surrounding region of fistulizing CD were analyzed histologically and by RNA sequencing (RNA-seq). Significantly modulated genes and TSG-6 expression were validated by RT-PCR, WB and immunofluorescence assays [N=20]. TSG-6 expression was reconstituted in Caco-2 cell line and primary perifistula-derived fibroblasts, and proliferative and migratory assays were performed. RESULTS: A marked different organization of extracellular matrix was found across fistula and perifistula regions with an increased expression of integrins, hyaluronan synthases, TSG-6 and MMPs in the fistula. TSG-6 overexpression in Caco-2 cells reduced proliferation, promoted the EMT transcription factor SNAIL, and, in co-stimulation with TGFβ1, migration. The acquisition of TSG-6 increased SNAI1 and hyaluronan synthases levels, and led to activated phenotype of perifistula-derived fibroblasts. Positive Pearson correlation was observed between TSG-6 expression and mechanosensitive proteins in fistula tissue. CONCLUSIONS: By mediating changes in the extracellular matrix organization, TSG-6 triggers the EMT transcription factor SNAIL through the activation of mechanosensitive proteins. These data point to TSG-6 as a new potential target for the treatment of perianal fistula.
Project description:This study compared the subgingival microbiota of subjects with periodontitis to those with periodontal health using the Human Oral Microbe Identification Microarray (HOMIM).