Project description:Selected brain regions of mice with chronic DSS colitis and controls, and mice with colitis caused by induced, intestinal epithelial-specific Opa1 knock-out to study the impact of gut inflammation on the brain
Project description:Whole right brain hemispheres of mice with colitis caused by induced, intestinal epithelial-specific Opa1 knock-out to study the impact of gut inflammation on the brain
Project description:The identification of inflammatory bowel disease (IBD) susceptibility genes by genome-wide association has linked this pathology to autophagy, a lysosomal degradation pathway that is crucial for cell and tissue homeostasis. Here, we describe autophagin-1 (ATG4B) as an essential protein in the control of inflammatory response during experimental colitis. In this pathological condition, ATG4B protein levels increase paralleling the induction of autophagy. Moreover, ATG4B expression is significantly reduced in affected areas of the colon from IBD patients. Consistently, atg4b-/- mice present Paneth cell abnormalities, as well as an increased susceptibility to DSS-induced colitis. Atg4b-deficient mice exhibit significant alterations in proinflammatory cytokines and mediators of the immune response to bacterial infections, which are reminiscent of those found in patients with Crohn’s disease or ulcerative colitis. Additionally, antibiotic treatments and bone marrow transplantation from wild-type mice reduced colitis in atg4b-/- mice. Taken together, these results provide additional evidence on the importance of autophagy in intestinal pathologies and describe ATG4B as a novel protective protein in inflammatory colitis. Finally, we propose that Atg4b-null mice are a suitable model for in vivo studies aimed at testing new therapeutic strategies for intestinal diseases associated with autophagy deficiency Seven samples were collected in total: three from wild-type mice (1 from the ileum and the colon of control mice, and 1 from the colon of a DSS-treated mouse) and four from Atg4b knock-out mice (1 from the ileum and the colon of control mice, and 2 from the colon of DSS-treated mice).
Project description:2’-fucosyllactose (2’-FL) is a unique oligosaccharide in human milk. We previously reported that 2’-FL protected intestinal integrity, modulated the gut microbial metabolism, and ameliorated intestinal inflammation in adult mice. This study aimed to elucidate mechanisms underlying the direct effects of 2’-FL on intestinal epithelial cells (IECs) for preventing colitis in adulthood. We found that 2’-FL transactivated EGFR in a colonic epithelial cell line, which required 2’-FL-stimulated release of HB-EGF from the cell membrane. Further, findings of 2’-FL-stimulated ADAM17 kinases activity on the cell surface and docking site of 2’-FL to the metalloprotease domain of ADAM17 suggest that 2’-FL could enhance ADAM17 shedding activity for releasing HB-EGF. Remarkably, apoptosis and disruption of tight junction induced by a proinflammatory cytokine and oxidative stress were mitigated by 2’-FL in wild-type, but not EGFR knock-out cell line and colonoids. By using the murine model of colonic injury and colitis induced by DSS, 2’-FL treatment prevented colitis, decreased epithelial apoptosis, and preserved intestinal barrier in wild-type adult mice. These effects were diminished in mice with EGFR deletion in IECs. This study demonstrates a novel mechanism underlying the direct transactivation of EGFR in IECs by 2’-FL that mediates protection of IECs during intestinal inflammation in adulthood.
Project description:B cells expand during the recovery after DSS-induced colonic inflammation and might play a role in influencing tissue repair. To analyze the impact B cells might have on intestinal epithelial cells and stromal cells during recovery after intestinal injury the transcriptional profile of these mice was analysed in mice depleted of B cells and control mice on day 14 after DSS colitis.
Project description:We compared the transcriptional signatures of the colonic mucosa from control mice (WT) versus mice deficient for the epithelial pantetheinase Vnn1 (Vnn1KO) or overexpressing Vnn1 specifically in intestinal epithelial cells (VIVA transgenic mice), during the development of DSS-induced colitis.
Project description:Intestinal tissue samples from dextran sodium sulfate-induced colitis mice were analyzed on their transcriptomic changes using RNA-seq to elucidate the effects of extracellular vesicles pretreatment on the colitis-associated gene expressions.
Project description:Desmosomes play an underexplored role in intestinal homeostasis and are linked to the pathogenesis of inflammatory bowel diseases. We found a novel function of the desmosomal plaque protein Plakoglobin (JUP) in initiating the innate immune response to facilitate intestinal inflammation. Tissue samples from Crohn’s disease (CD) patients revealed a loss of JUP, which was mirrored in a mouse model of dextran sodium sulfate-induced (DSS) colitis. Inducible intestinal epithelial-specific knock-out of Jup (iVilCreERT2Jupfl/fl) in mice resulted in increased submucosal infiltration of macrophages and neutrophils, along with activation of the inflammasome. This was paralleled by p38MAPK phosphorylation, while loss of intestinal epithelial barrier function was absent. In DSS-colitis, epithelial Jup-deficiency impaired recovery and enhanced IL23/IL17-signaling. Intestinal organoids lacking Jup demonstrated NLRP1 inflammasome activation, indicated by increased IL1β and IL18 levels, which was attenuated by p38MAPK inhibition. In silico analysis and co-immunoprecipitation confirmed a direct interaction between JUP and p38MAPK, revealing a regulatory mechanism where JUP limits inflammasome signaling in intestinal epithelial cells. These effects were blunted by NLRP1/3 inhibitor ADS032. These findings identify JUP as a critical modulator of epithelial innate immunity in the gut. The loss of JUP in tissues from CD patients underscores its potential relevance in disease pathology.
Project description:Paneth cells, intestine-originated innate immune-like cells, are important for maintenance of the intestinal stem cell niche, gut microbiota, and gastrointestinal barrier. Dysfunctional Paneth cells under pathological conditions are a site of origin for intestinal inflammation. However, mechanisms underlying stress-induced Paneth cell dysregulation remains unclear. We have previously reported that deletion of SIRT1 in the intestinal epithelium (SIRT1 iKO) leads to hyperaction of Paneth cells along with an increased sensitivity to Dextran sodium sulfate (DSS)-induced colitis. We recently generated a Paneth-cell specific SIRT1 KO mouse model (SIRT1 PKO). Similar to mice with SIRT1 iKO mice, SIRT1 PKO mice had increased abundance as well as hyperactivation of Paneth cells in vivo and in cultured intestinal organoids. However, in contrast to the hypersensitivity of SIRT1 iKO mice to chemical- or age-induced inflammation, SIRT1 PKO mice were protected from Dextran sodium sulfate (DSS)-colitis.
Project description:Small intestinal group 3 innate lymphoid cells (ILC3) from ILC3-conditional BMAL1 knock out mice or littermate control mice were sort-purified for transcriptional analysis
