Project description:The early phase of colonic epithelial wound healing involves cellular reprogramming to a fetal-like state and reorganization of discrete crypt units into merged wound channels. After re-epithelialization is complete, a latter phase restoring homeostatic signaling and crypt patterning must occur. However, the signals that mediate this regenerative transition are unknown. Here we show that injury-associated upregulation of a cytokine receptor, tumor necrosis factor (TNF) receptor 2 (R2, TNFR2, Tnfrsf1b), suppresses fetal-like signaling and promotes crypt production. We used tissue clearing and whole-mount imaging, RNA-Seq, and organoid cultures to characterize mice with a colonic epithelial-specific deletion of TNFR2. These mice exhibited increased crypt size and reduced fission in adult homeostasis and after colitis, abnormal persistence of fetal-like molecular markers in organoids and after injury, reduced terminal differentiation, and increased proliferative potential. These results demonstrate how epithelial cells can adapt to inflammatory cues to regulate wound healing morphogenesis and signaling.
Project description:Colonic epithelial repair is a key determinant of health. After injury, repair initiates through phenotypic reprogramming of wounded epithelium to a regenerative state permissive for the activation of alternative stem cell populations and healing. Although cytokine signals such as interferon help induce regenerative reprogramming, the signals that modify this state as the wound resolves remain largely unknown. Here we show that, during healing, the late upregulation of a cytokine receptor, tumor necrosis factor (TNF) receptor 2 (R2, TNFR2, Tnfrsf1b), clears the phenotype of regenerative signaling and restores homeostatic patterns of epithelial differentiation. Mice lacking epithelial-specific expression of TNFR2 also failed to complete colon ulcer healing, suggesting that full repair requires coordination of both regenerative and homeostatic epithelial phenotypes. In single-cell RNA-seq experiments, we find that colonic epithelial organoids grown from Tnfr2-/- mice retain a highly enriched census of progenitor cells and reduced representation of differentiated cells, consistent with TNFR2's role in promoting differentiation. These results demonstrate how epithelial cells adapt to inflammatory cues to choreograph repair.
Project description:Aspirin (ASA) is a proven chemoprotective agent for sporadic and hereditary colorectal cancer (CRC), though mechanisms underlying these effects are incompletely understood. Human-derived epithelial organoids are an ideal system to study host-environment interactions in the colon across individuals. Here, colonic organoids from a diverse cohort of African-Americans (AA) and European-Americans (EA) were used to profile genomic and cellular ASAresponses.
Project description:Background & Aims: Aspirin (ASA) is a proven chemoprotective agent for colorectal cancer; yet, mechanisms underlying these effects are incompletely understood. Human organoids are an ideal system to study genomic and epigenomic host-environment interactions. Here, we utilize human colonic organoids to profile ASA responses on genome-wide gene expression and chromatin accessibility. Methods: Human colonic organoids from one individual were cultured and treated in triplicate with 3mM ASA or vehicle control (DMSO) for 24 hours. Gene expression and chromatin accessibility were measured using RNA- and ATAC-sequencing, respectively. Differentially expressed genes were analyzed using DESeq2. Gene set enrichment was performed by SetRank. Differentially accessible peaks were analyzed using DiffBind and EdgeR. Motif enrichment was determined using HOMER and diffTF. Results: The results yielded strong transcriptional responses to ASA treatment with significant enrichment for fatty acid oxidation and PPAR signaling in the normal colonic epithelium that were validated in independent organoid lines. A large number of differentially accessible chromatin regions were found in response to ASA treatment with significant enrichment for Fos, Jun and Hnf transcription factor motifs. Integrated analysis of epigenomic and genomic treatment responses highlighted genes and regulatory regions that could mediate ASA’s specific effects in the colon including those involved in chemoprotection and/or toxicity. Conclusions: Assessment of chromatin accessibility and transcriptional responses to ASA yielded new observations about genome-wide effects in the colon facilitated by application of human colonic organoids. This framework can be applied to study colonic ASA responses between individuals and populations in future.
Project description:Objective: Cytokines produced by epithelial and immune cells can act upon one another to promote mucosal healing- a process that goes awry with chronic inflammation as in inflammatory bowel disease. TNFSF13 is a cytokine important for B cell function, but its role in epithelial cell behavior and contribution to inflammatory bowel disease is poorly understood. Design: We performed histological and functional assays, single cell transcriptomics, and imaging mass cytometry on tissue-derived colonoids or biopsies from a patient with very early onset inflammatory bowel disease (VEO-IBD) harboring a novel TNFSF13 variant. To confirm causal, variant-driven phenotypes, parallel experiments were performed in induced pluripotent stem cell (iPSC)- derived colon organoids engineered with the same TNFSF13 variant. Results: TNFSF13 variant colonoids exhibited reduced TNFSF13 expression associated with increased proliferation and reduced apoptosis, which was confirmed in iPSC-derived colon organoids. Single cell RNA-sequencing and flow cytometry defined FAS as the predominant colonic epithelial receptor for TNFSF13. TNFSF13 variant colon biopsies demonstrated a shift in tissue B cell populations consistent with altered differentiation of memory B cells. Finally, imaging mass cytometry revealed an increase in epithelial-associated B cells in TNFSF13 variant colon tissue sections compared to healthy and non-monogenic VEO-IBD controls. Conclusions: The current study defines a previously unknown role for the cytokine TNFSF13 as a regulator of colonic epithelial proliferation and apoptosis. Furthermore, this study suggests that variant TNFSF13 can contribute to aberrant epithelial- B cell crosstalk in the human colon.