Control of Virulence Gene Expression in Citrobacter rodentium by Trascription Factor RegA
Ontology highlight
ABSTRACT:
ORGANISM(S): Citrobacter rodentium
PROVIDER: GSE12876 | GEO | 2008/09/22
SECONDARY ACCESSION(S): PRJNA111057
REPOSITORIES: GEO
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Project description:Identification of the targets of RegA with and without bicarbonate stimulation by comparing RegA knockout to multicopy RegA transgenics. RegA is an AraC like transcription factor identified in a mutational screen for virulence genes in Citrobacter rodentium, an attaching and effacing pathogen that causes transmissible colonic hyperplasia in mice. This experiment compares the RegA null strain with a multicopy plasmid rescue of this null strain in the presence and absence of bicarbonate with the aim of identifying pathogenesis related genes related to the early and late stages of attachment and effacement. Keywords: genetic modification, transcription factor, induction A strain of Citrobacter rodentium with a knockout of RegA was compared to the same strain rescued with a multicopy plasmid containing the wildtype RegA gene. These strains were analyzed with and without bicarbonate in an unconnected two factor design with dye balanced biological replicates.
2010-05-19 | E-GEOD-12876 | biostudies-arrayexpress
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.
2020-02-18 | E-MTAB-7503 | biostudies-arrayexpress
Project description:Analysis of the evolutionary adaptation of an AraC-like global regulatory protein in the murine enteric pathogen Citrobacter rodentium
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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.
2013-06-01 | GSE45682 | GEO
Project description:Colonic goblet cells respond to invading enteropathogens by secreting Muc2 mucin and other specific goblet cell proteins that physically entrap and expel microbes away from the epithelium. At present, it is unclear how innate effectors in the gut, including small cationic cathelicidin peptides secreted by the intestinal epithelium and leukocytes, contribute to mucus barrier defense during infections. In this study, we used cathelicidin-deficient (Camp-/-) mice, colonoids, and human colonic LS174T goblet cells to elucidate the mechanisms by which cathelicidin regulates goblet cell secretions in innate host defense against attaching/effacing Citrobacter rodentium. We showed that even though Camp-/- littermates infected with C. rodentium displayed increased fecal shedding and epithelial colonization, Muc2 mucin granules were retained in bloated colonic goblet cells that impaired mucus secretion and expressed less mucus-associated proteins, as quantified by proteomic analysis. C. rodentium infected Camp-/- littermates showed impaired reactive oxygen species (ROS) production and transcriptomic profiling associated with decreased ROS biosynthesis and an increase in ROS negative regulators. Camp-/- bone marrow derived macrophages produced less ROS than their wild-type counterparts. In LS174T goblet cells, human cathelicidin LL-37 promptly induced the secretion of goblet cell-associated TFF3 and RELMβ, which was dependent on ROS production. These findings demonstrate that cathelicidin signaling in colonic goblet cells regulates mucus and mucin-associated protein secretion via an ROS-dependent mechanism to clear bacterial infections and restore gut homeostasis.
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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.
2013-06-01 | E-GEOD-45682 | biostudies-arrayexpress
Project description:CDK1-formin signal confers microvillar effacement by an attaching and effacing (A/E) pathogen
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Project description:http://www.sanger.ac.uk/resources/downloads/bacteria/citrobacter-rodentium.htmlThis data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
2013-10-07 | E-ERAD-168 | biostudies-arrayexpress
Project description:The gut microbiota plays a crucial role in susceptibility to enteric pathogens, including Citrobacter rodentium, a model extracellular mouse pathogen that colonizes the colonic mucosa. C. rodentium infection outcomes vary between mouse strains, with C57BL/6 and C3H/HeN mice clearing and succumbing to the infection, respectively. Kanamycin (Kan) treatment at the peak of C57BL/6 mouse infection with Kan-resistant C. rodentium resulted in relocalization of the pathogen from the colonic mucosa and cecum to solely the cecal luminal contents; cessation of the Kan treatment resulted in rapid clearance of the pathogen. We now show that in C3H/HeN mice, following Kan-induced displacement of C. rodentium to the cecum, the pathogen stably colonizes the cecal lumens of 65% of the mice in the absence of continued antibiotic treatment, a phenomenon that we term antibiotic-induced bacterial commensalization (AIBC). AIBC C. rodentium was well tolerated by the host, which showed few signs of inflammation; passaged AIBC C. rodentium robustly infected naive C3H/HeN mice, suggesting that the AIBC state is transient and did not select for genetically avirulent C. rodentium mutants. Following withdrawal of antibiotic treatment, 35% of C3H/HeN mice were able to prevent C. rodentium commensalization in the gut lumen. These mice presented a bloom of a commensal species, Citrobacter amalonaticus, which inhibited the growth of C. rodentium in vitro in a contact-dependent manner and the luminal growth of AIBC C. rodentium in vivo. Overall, our data suggest that commensal species can confer colonization resistance to closely related pathogenic species. IMPORTANCE Gut bacterial infections involve three-way interactions between virulence factors, the host immune responses, and the microbiome. While the microbiome erects colonization resistance barriers, pathogens employ virulence factors to overcome them. Treating mice infected with kanamycin-resistant Citrobacter rodentium with kanamycin caused displacement of the pathogen from the colonic mucosa to the cecal lumen. Following withdrawal of the kanamycin treatment, 65% of the mice were persistently colonized by C. rodentium, which seemed to downregulate virulence factor expression. In this model of luminal gut colonization, 35% of mice were refractory to stable C. rodentium colonization, suggesting that their microbiotas were able to confer colonization resistance. We identify a commensal bacterium of the Citrobacter genus, C. amalonaticus, which inhibits C. rodentium growth in vitro and in vivo. These results show that the line separating commensal and pathogenic lifestyles is thin and multifactorial and that commensals may play a major role in combating enteric infection.
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Project description:Citrobacter rodentium strain DBS100 causes an infection of the intestines in mice. It provides an important model for human gastrointestinal pathogens, such as enteropathogenic and enterohemorrhagic Escherichia coli, which cause life-threatening infections. To identify the genetic determinants that are common across the enteropathogenic bacteria, we sequenced the DBS100 genome.
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