Project description:Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo. Analysis of genes differentially expressed between WT, Batf3 KO and Notch2 KO colons following C. rodentium infection. Mice were infected with 2 x 10^9 C. rodentium and colons harvested at either Day 4 or Day 9.
Project description:Previous experiments have shown that hexuronates regulate EHEC virulence, here we look at glucuronic acid effect on citrobacter rodentium
Project description:Opioids analgesics are frequently prescribed in the United States and worldwide. However, serious side effects such as addiction, immunosuppression and gastrointestinal symptoms limit their use. It has been recently demonstrated that morphine treatment results in significant disruption in gut barrier function leading to increased translocation of gut commensal bacteria. Further study indicated distinct alterations in the gut microbiome and metabolome following morphine treatment, contributing to the negative consequences associated with opioid use. However, it is unclear how opioids modulate gut homeostasis in the context of a hospital acquired bacterial infection. In the current study, a mouse model of C. rodentium infection was used to investigate the role of morphine in the modulation of gut homeostasis in the context of a hospital acquired bacterial infection. Citrobacter rodentium is a natural mouse pathogen that models intestinal infection by enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) and causes attaching and effacing lesions and colonic hyperplasia. Morphine treatment resulted in 1) the promotion of C. rodentium systemic dissemination, 2) increase in virulence factors expression with C. rodentium colonization in intestinal contents, 3) altered gut microbiome, 4) damaged integrity of gut epithelial barrier function, 5) inhibition of C. rodentium-induced increase in goblet cells, and 6) dysregulated IL-17A immune response. This is the first study to demonstrate that morphine promotes pathogen dissemination in the context of intestinal C. rodentium infection, indicating morphine modulates virulence factor-mediated adhesion of pathogenic bacteria and induces disruption of mucosal host defense during C. rodentium intestinal infection in mice. This study demonstrates and further validates a positive correlation between opioid drug use/abuse and increased risk of infections, suggesting over-prescription of opioids may increase the risk in the emergence of pathogenic strains and should be used cautiously. Therapeutics directed at maintaining gut homeostasis during opioid use may reduce the comorbidities associated with opioid use for pain management.
Project description:The mechanisms by which the mouse pathogen Citrobacter rodentium triggers effacement of the brush border microvilli, colitis, hyperplasia and dysbiosis remain poorly understood. We investigated the impact of C. rodentium infection on the proteomic and metabolic landscapes of intestinal epithelial cells (IECs) in vivo using isobaric labeling proteomics and targeted metabolomics. We found that infection depletes proteins involved in butyrate uptake, glycolysis, TCA cycle, lipid metabolism and oxidative phosphorylation with aparallel, increased production of creatine/phosphocreatine and cholesterol. The evolving ecological niche within the infected gut was concomitant with a reduction in butyrate-producing commensal bacteria and expansion of Proteobacteria that can metabolize cholesterol. These changes coincide with the modulation of IEC transcription factors by C. rodentium, specifically phosphorylation of Kdm5a, demethylation of histone H3 (Lys-4) and cleavage of Srebp2. Taken together our results show that whilst engaging with the host in a race to control innate immune responses, C. rodentium and the changing microbiota shape the metabolism flow in IECs.
Project description:We generated conditional knockout of MHCII in intestinal epithelial cells in C57BL/6 mice (I-AbΔIEC) and compared their colonic transcriptome in control and Citrobacter rodentium infected mice. I-AbWT or I-AbΔIEC mice were orally gavaged with Citrobacter rodentium DBS100