Project description:The intestinal epithelial barrier plays a critical role in the mucosal immunity. However, it remains largely unknown how the epithelial barrier is maintained after damage. Here we show that FGF2 synergizes with IL-17A to induce genes for repairing of damaged epithelium. Deficiency of FGF2 or IL-17A resulted in impaired epithelial proliferation, increased pro-inflammatory microbiota outgrowth, and consequently worse pathology in a DSS-induced colitis model.
Project description:STAT3 is a pleiotropic transcription factor with important functions in cytokine signalling in a variety of tissues. However, the role of STAT3 in the intestinal epithelium is not well understood. Here we demonstrate that development of colonic inflammation is associated with the induction of STAT3 activity in intestinal epithelial cells (IEC). Studies in genetically engineered mice showed that epithelial STAT3 activation in DSS colitis is dependent on IL-22 rather than IL-6. IL-22 was secreted by colonic CD11c+ cells in response to Toll-like receptor stimulation. Conditional knockout mice with an IEC specific deletion of STAT3 activity were highly susceptible to experimental colitis, indicating that epithelial STAT3 regulates gut homeostasis. STAT3IEC-KO mice, upon induction of colitis, showed a striking defect of epithelial restitution. Gene chip analysis indicated that STAT3 regulates the cellular stress response, apoptosis and pathways associated with wound healing in IEC. Consistently, both IL-22 and epithelial STAT3 were found to be important in wound-healing experiments in vivo. In summary, our data suggest that intestinal epithelial STAT3 activation regulates immune homeostasis in the gut by promoting IL-22-dependent mucosal wound healing. 4 samples of colon epithelium were analyzed from 4 mice (2 per group Stat3flfl VillinCre- and Stat3flfl VillinCre+, respectively) after they had been treated with DSS (2.5%) for 5 days
Project description:The goal of this study was to elucidate the effects of inflammation on bone metabolism. As we found IL-17A is induced immediately after bone injury and Il17aâ/â mice showed delayed healing, we analyzed the effects of IL-17A on mesenchymal cells in the repair tissue. Most of the IL-17RA+ cells were PαS cells. We collected these cells and analyzed their response to IL-17A by RNA sequencing. This analysis will provide a mechanistic insight into the mechanism of how IL-17A promote bone formation in the context of bone fracture healing. PαS cells were harvested from the injury tissue of wild-type mice and cultured with or without IL-17A or BMP-2. RNAs were harvested at day 7.
Project description:Interleukin-23 (IL-23) and IL-17 are cytokines currently being targeted in clinical trials. Although inhibition of these cytokines is effective for treating psoriasis, IL-12/23 inhibition attenuates Crohn's disease, while IL-17A or IL-17RA inhibition exacerbates disease. This dichotomy between IL-23 and IL-17 was effectively modeled in the mdr1a- /- mouse model of colitis. IL-23 inhibition attenuated disease by decreasing colonic inflammation while enhancing Treg accumulation. Exacerbation of colitis by IL-17A or IL-17RA inhibition was associated with severe weakening of the intestinal epithelial barrier, culminating in increased colonic inflammation and accelerated mortality. These data show that IL-17A acts on intestinal epithelium to promote barrier function and provides insight into mechanisms underlying exacerbation of Crohn's disease when IL-17A or IL-17RA is inhibited.
Project description:The goal of this study was to elucidate the effects of inflammation on bone metabolism. As we found IL-17A is induced immediately after bone injury and Il17a−/− mice showed delayed healing, we analyzed the effects of IL-17A on mesenchymal cells in the repair tissue. Most of the IL-17RA+ cells were PαS cells. We collected these cells and analyzed their response to IL-17A by RNA sequencing. This analysis will provide a mechanistic insight into the mechanism of how IL-17A promote bone formation in the context of bone fracture healing.
Project description:STAT3 is a pleiotropic transcription factor with important functions in cytokine signalling in a variety of tissues. However, the role of STAT3 in the intestinal epithelium is not well understood. Here we demonstrate that development of colonic inflammation is associated with the induction of STAT3 activity in intestinal epithelial cells (IEC). Studies in genetically engineered mice showed that epithelial STAT3 activation in DSS colitis is dependent on IL-22 rather than IL-6. IL-22 was secreted by colonic CD11c+ cells in response to Toll-like receptor stimulation. Conditional knockout mice with an IEC specific deletion of STAT3 activity were highly susceptible to experimental colitis, indicating that epithelial STAT3 regulates gut homeostasis. STAT3IEC-KO mice, upon induction of colitis, showed a striking defect of epithelial restitution. Gene chip analysis indicated that STAT3 regulates the cellular stress response, apoptosis and pathways associated with wound healing in IEC. Consistently, both IL-22 and epithelial STAT3 were found to be important in wound-healing experiments in vivo. In summary, our data suggest that intestinal epithelial STAT3 activation regulates immune homeostasis in the gut by promoting IL-22-dependent mucosal wound healing.
Project description:Diabetic foot ulcers (DFU) are one of the major complications in type II diabetes patients and can result in amputation and morbidity. Although multiple approaches are used clinically to help wound closure, many patients still lack adequate treatment. Here we show that IL-20 subfamily cytokines are upregulated during normal wound healing. While there is a redundant role for each individual cytokine in this subfamily in wound healing, mice deficient in IL-22R, the common receptor chain for IL-20, IL-22, and IL-24, display a significant delay in wound healing. Furthermore, IL-20, IL-22 and IL-24 are all able to promote wound healing in type II diabetic db/db mice. When compared to other growth factors such as VEGF and PDGF that accelerate wound healing in this model, IL-22 uniquely induced genes involved in reepithelialization, tissue remodeling and innate host defense mechanisms from wounded skin. Interestingly, IL-22 treatment showed superior efficacy compared to PDGF or VEGF in an infectious diabetic wound model. Taken together, our data suggest that IL-20 subfamily cytokines, particularly IL-20, IL-22, and IL-24, might provide therapeutic benefit for patients with DFU.
Project description:IBD is a complex autoimmune disease characterized by dysregulated interactions between host immune responses and microbiome at the intestinal epithelium interface. Here we identified shared protein alterations in intestinal epithelial differentiation and function between IBD and Citrobacter rodentium infected FVB mice. We discovered that prophylactic treatment with the mucosal healing therapy IL-22.Fc in the infected FVB mice reduced disease severity and rescued the mice from lethality. Notably, we observed an emergence of intermediate undifferentiated intestinal epithelial cells upon infection, with disrupted expression of the solute transporter machinery as well as components critical for intestinal barrier integrity. Multi-omics analyses revealed that with IL-22.Fc treatment several disease associated changes were prevented (including disruption of the solute transporter machinery), and proper physiological homeostatic functions of the intestine was restored. Taken together, we unveiled the disease relevance of the C. rodentium induced colitis model to IBD and demonstrated the protective role of the mucosal healing therapy IL-22.Fc in ameliorating the epithelial dysfunction.
Project description:Paneth cell metaplasia (PCM) is a phenomenon in which Paneth cells, typically found in the small intestine, appear in the colonic epithelium of patients with ulcerative colitis (UC). Our study demonstrates that the PCM occurrence correlates with disease duration and active inflammation. Furthermore, we reveal that the inflammation-induced cytokine IL-22 suppresses Notch signaling, thereby promoting PCM formation in the colonic epithelium while simultaneously inducing REG3A expression in metaplastic niches. In vitro, we show that Reg3a directly enhances cell proliferation and promotes wound healing using mouse colonic organoids. In vivo, Reg3aΔIEC mice in both acute and chronic DSS-induced colitis models exhibit delayed wound healing. Additionally, studies conducted with patient-derived human colonic organoids revealed that REG3A administration stimulates cell proliferation and accelerates wound healing. These findings underscore a novel protective role of PCM-mediated REG3A in the colonic epithelium of patients with UC.