Project description:Small intestinal Paneth cells regulate host-microbial homeostasis and defects in autophagy and host defense pathways have been associated with inflammatory bowel diseases (IBD). Genetic variants in TL1A (TNFSF15) have been associated with susceptibility to and severity of IBD. TL1A expression is increased in IBD patients, particularly in TL1A risk allele carriers. However, the effects of TL1A on the function of ileal Paneth cells and downstream effect on commensal microbiota and development of ileitis has not been investigated. Here, we demonstrate that TL1A overexpression in mice (Tl1a-tg) induces Paneth cell hyperplasia and morphological abnormalities that precedes the development of spontaneous ileitis. In Crohn’s disease (CD) patients, ileal TL1A expression was associated with abnormal Paneth cell phenotypes. Deficiency of the TL1A receptor DR3 in Paneth cells resulted in Paneth cell abnormalities suggesting a direct effect of TL1A on Paneth cells which we confirmed in human CD patient-derived Paneth cell enriched organoid cultures. Commensal microbiota were required for TL1A-mediated Paneth cell dysfunction, and development of spontaneous ileitis. Overexpression of TL1A results in dysbiosis with an enrichment in short chain fatty acid-producing bacteria Bifidobacterium and Allobaculum and metabolomic analysis revealed an increase of the metabolite acetate. Acetate supplementation in germ-free or SPF housed mice caused ileal inflammation and elevated IFN-g secretion, suggesting that acetate is sufficient to cause ileitis. Our findings provide a mechanistic link between overexpression of TL1A in CD patients with TNFSF15 risk variants, Paneth cell dysfunction, intestinal dysbiosis and enrichment of acetate-producing bacteria that promote ileal inflammation.
Project description:TL1A overexpression in Crohn’s Disease patients and mice alters Paneth cell biology and intestinal microbiota in promoting ileal inflammation
Project description:We previously showed that abnormal morphology phenotype of ileal Paneth cells (Paneth cell phenotype [PCP]; as a surrogate for PC function) correlate with genetics, microbiota compositions, and aggressive outcome in Crohn’s disease (CD) patients. Given the shared genetics and clinical features between CD and ulcerative colitis (UC), we hypothesized that abnormal PCP also negatively modulates UC outcomes. As PCs has the highest density in the ileum, we further hypothesized that abnormal PCP from the terminal ileum could increase the risk of development of pouch complications after UC total colectomy and ileal pouch anal anastomosis (IPAA).
Project description:An indepth analysis of Paneth cell transcriptome at single cell level has not been available. Existing intestinal epithelial cell scRNA dataset contain many cell types, where Paneth cells represent a small portion. We used a flow cytometry based approach to enrich and isolate relatively pure Panethc cells from a newly developed Paneth cell reporter mouse line (Lyz1-3'UTR-IRES-CreER; Rosa26R-tdTomato). Single cell RNA sequencing was performed on purified duodenal and ileal Paneth cells of mice housed under specific pathogen free condition.
Project description:The transcriptome changes of the ileal mucosa in suckling piglets during early postnatal life were analysed to contribute to the knowledge of a pig’s gut development. In addition, the ileal transcriptome of suckling piglets was compared with that of age-matched weaned piglets (weaned at the age of 21 days) to elucidate the effect of weaning on the developing gut. DNA microarray was used to analyse the change of transcriptome profiles and biological pathways in porcine ileum that occurred during the developmental or the weaning process.
Project description:Paneth cells express Lyz1, a gene encoding for lysozyme. To investigate the transcriptomic profiles of wild type and Lyz1-knockout mouse ileal lamina propria cells, we performed single-cell RNA-seq.
Project description:The spatial organization of gut microbiome is essential for their interactions with the host. Recently, microbiota alteration in ileum is getting the increasing recognition due to the close interplay with inflammatory diseases and the tumor immunosurveillance. However, how ileal microbiome is spatially regulated remains unclear. Here, we show that DNA-damaging chemotherapy specifically remodels microbiota in ileal mucosa, resulting in the overgrowth of local family Lachnospiraceae that promotes antitumor immunity and synergizes with immune checkpoint blockage. Mechanistically, the prominent proliferative state of transit amplifying cells (TACs) in the ileal crypt presents a vulnerability to chemotherapy-caused genomic stress, resulting in the accumulation of cytosolic dsDNA that subsequently activates AIM2 inflammasome. AIM2-dependent production of IL18 boosts Th1 immunity in ileal lamina propria, which further impairs the antimicrobial host defense of proximal Paneth cells via activating IFN-γ-JAK-STAT signaling. Our findings demonstrate that AIM2 inflammasome shapes ileal microbiome via governing the compartmentalized cellular interplay in ileal crypt, providing mechanistic insights into the regulation of gut biogeography and implicating therapeutic strategies of spatial microbiome intervention using chemotherapy.
Project description:To determine the potential molecular mechanisms by which STAT5 signaling control ileal Paneth cell homeostasis, we isolated total RNA from ileal intact crypts of STAT5+/+, STAT5DIEC-/- and STAT5DIEC+++ mice and performed RNA sequencing (RNA-seq). With an average of 22.3 million reads per sample, we observed 27540 transcripts when reads were aligned to the mm10 genome with annotations provided by Ensembl. Transcripts were filtered, requiring at least 3 reads in 50% of samples within at least one condition, leaving 10197 transcripts for analysis. To identify differentially-regulated transcripts, we performed ANOVA (FDR-corrected p<0.05) and required the fold change to exceed 1.5.
