技术资料

BACKGROUND & AIMS Down-regulation of chloride transporter SLC26A3 or down-regulated in adenoma (DRA) in colonocytes has recently been linked to the pathogenesis of ulcerative colitis (UC). Because exaggerated immune responses are one of the hallmarks of UC,these current studies were undertaken to define the mechanisms by which loss of DRA relays signals to immune cells to increase susceptibility to inflammation. METHODS NanoString Immunology Panel,fluorescence assisted cell sorting,immunoblotting,immunofluorescence,and quantitative real-time polymerase chain reaction assays were used in wild-type and DRA knockout (KO) mice. Interleukin (IL)-33 blocking was used to determine specific changes in immune cells and co-housing/broad spectrum antibiotics administration,and ex vivo studies in colonoids were conducted to rule out the involvement of microbiota. Colonoid-derived monolayers from healthy and UC patient biopsies were analyzed for translatability. RESULTS There was a marked induction of Th2 (>2-fold),CD4+ Th2 cells (~8-fold),RORt+ Th17,and FOXP3+ regulatory T cells (Tregs). DRA KO colons also exhibited a robust induction of IL-33 (>8-fold). In vivo studies using blocking of IL-33 established that T2 immune dysregulation (alterations in ILC2,Th2,and GATA3+ iTregs) in response to loss of DRA was due to altered epithelial-immune cell crosstalk via IL-33. CONCLUSIONS Loss of DRA in colonocytes triggers the release of IL-33 to drive a type 2 immune response. These observations emphasize the critical importance of DRA in mucosal immune homeostasis and its implications in the pathogenesis of UC. View Publication

Cellular senescence and the senescence-associated secretory phenotype (SASP) are implicated in aging and age-related disease,and SASP-related inflammation is thought to contribute to tissue dysfunction in aging and diseased animals. However,whether and how SASP factors influence the regenerative capacity of tissues remains unclear. Here,using intestinal organoids as a model of tissue regeneration,we show that SASP factors released by senescent fibroblasts deregulate stem cell activity and differentiation and ultimately impair crypt formation. We identify the secreted N-terminal domain of Ptk7 as a key component of the SASP that activates non-canonical Wnt / Ca2+ signaling through FZD7 in intestinal stem cells (ISCs). Changes in cytosolic [Ca2+] elicited by Ptk7 promote nuclear translocation of YAP and induce expression of YAP/TEAD target genes,impairing symmetry breaking and stem cell differentiation. Our study discovers secreted Ptk7 as a factor released by senescent cells and provides insight into the mechanism by which cellular senescence contributes to tissue dysfunction in aging and disease. View Publication

BACKGROUND & AIMS The etiology of abdominal pain in postinfectious,diarrhea-predominant irritable bowel syndrome (PI-IBS-D) is unknown,and few treatment options exist. Catechol-O-methyltransferase (COMT),an enzyme that inactivates and degrades biologically active catecholamines,plays an important role in numerous physiologic processes,including modulation of pain perception. Our objective was to determine the mechanism(s) of how decreased colonic COMT in PI-IBS-D patients contributes to the chronic abdominal pain phenotype after enteric infections. METHODS Colon neurons,epithelial cells,and macrophages were procured with laser capture microdissection from PI-IBS-D patients to evaluate cell-specific colonic COMT,microRNA-155 (miR-155),and tumor necrosis factor (TNF) ? expression levels compared to recovered patients (infection cleared: did not develop PI-IBS-D) and control individuals. COMT-/-,colon-specific COMT-/-,and miR-155-/- mice and human colonoids were used to model phenotypic expression of COMT in PI-IBS-D patients and to investigate signaling pathways linking abdominal pain. Citrobacter rodentium and trinitrobenzene sulfonic acid animal models were used to model postinflammatory changes seen in PI-IBS-D patients. RESULTS Colonic COMT levels were significantly decreased and correlated with increased visual analog scale abdominal pain ratings in PI-IBS-D patients compared to recovered patients and control individuals. Colonic miR-155 and TNF-? were increased in PI-IBS-D patients with diminished colonic COMT. COMT-/- mice had significantly increased expression of miR-155 and TNF-? in both colon tissues and dorsal root ganglia. Introduction of cV1q antibody (anti-TNF-?) into mice reversed visceral hypersensitivity after C rodentium and trinitrobenzene sulfonic acid. CONCLUSIONS Decreased colonic COMT in PI-IBS-D patients drives abdominal pain phenotypes via the COMT/miR-155/TNF-? axis. These important findings will allow new treatment paradigms and more targeted and personalized medicine approaches for gastrointestinal disorders after enteric infections. View Publication