14 research outputs found

    Gene expression suggests a T helper 17 response in mice when peroxisome proliferator-activated receptor γ (PPARγ) is antagonized.

    No full text
    <p>Gene expression data from colonic tissue of malnourished C57BL/6 mice was analyzed using quantitative real-time RT-PCR and reported as values normalized to β-actin. IL-6, IL-1β, MCP-1, CCL20, and CXCL1 were quantified at day 5PI (mice per group: n = 10) (A–E) while IL-6, TGF-β, and IL-17 were quantified 14 days PI (n = 10) (F–H). Asterisks indicate values where differences are statistically significant (<i>p</i><0.05) while bars connect groups where comparisons are made.</p

    Pharmacological blockade of peroxisome proliferator-activated receptor γ (PPARγ) associated with antimicrobial response and bacterial clearance.

    No full text
    <p>Enteroaggregative <i>Escherichia coli</i> (EAEC) burden in colon was assessed by quantitative real time RT-PCR using bacterial DNA isolated from feces of infected mice treated with PPARγ antagonist GW9662 (n = 9) or left untreated (n = 9). Data is presented as CFU/mg of tissue. S100A8 and S100A9 gene expression was analyzed in colonic tissue from C57BL/6 malnourished mice at day 5 days PI (n = 10) using quantitative real-time RT-PCR (B and C). S100 proteins are presented as values normalized to β-actin. Asterisks indicate values where differences are statistically significant (<i>p</i><0.05).</p

    Immune responses during enteroaggregative Escherichia coli (EAEC) infection in peroxisome proliferator-activated receptor γ (PPARγ)-deficient mice associated with bacterial clearance.

    No full text
    <p>Antigen specific recall responses of spleenocytes from mice infected with EAEC were measured ex vivo using the lymphocyte blastogenesis test. EAEC JM221 whole cell and whole cell sonicate were used in parallel to two negative controls, <i>E. coli</i> HS and mutant EAEC Aff/I strains as well as one positive control, concanavalin A (ConA). Lymphocyte proliferation is expressed stimulation indexes which are calculated by dividing the counts per minute (CPM) of antigen-stimulated wells by the CPM of unstimulated wells (A). IL-17 expression was assessed in colonic lamina propria (B) and whole blood (C) CD4+ T cells by flow cytometry and in the colon by quantitative real time RT-PCR (D) 14 days PI. Mice per group: n = 10. Asterisks indicate values where differences are statistically significant (<i>p</i><0.05) while bars connect groups where comparisons are made.</p

    The Role of Peroxisome Proliferator-Activated Receptor γ in Immune Responses to Enteroaggregative <em>Escherichia coli</em> Infection

    Get PDF
    <div><p>Background</p><p>Enteroaggregative <i>Escherichia coli</i> (EAEC) is recognized as an emerging cause of persistent diarrhea and enteric disease worldwide. Mucosal immunity towards EAEC infections is incompletely understood due in part to the lack of appropriate animal models. This study presents a new mouse model and investigates the role of peroxisome proliferator-activated receptor gamma (PPARγ) in the modulation of host responses to EAEC in nourished and malnourished mice.</p> <p>Methods/Principal Findings</p><p>Wild-type and T cell-specific PPARγ null C57BL/6 mice were fed protein-deficient diets at weaning and challenged with 5×10<sup>9</sup>cfu EAEC strain JM221 to measure colonic gene expression and immune responses to EAEC. Antigen-specific responses to <i>E. coli</i> antigens were measured in nourished and malnourished mice following infection and demonstrated the immunosuppressive effects of malnutrition at the cellular level. At the molecular level, both pharmacological blockade and deletion of PPARγ in T cells resulted in upregulation of TGF-β, IL-6, IL-17 and anti-microbial peptides, enhanced Th17 responses, fewer colonic lesions, faster clearance of EAEC, and improved recovery. The beneficial effects of PPARγ blockade on weight loss and EAEC clearance were abrogated by neutralizing IL-17 <i>in vivo</i>.</p> <p>Conclusions</p><p>Our studies provide <i>in vivo</i> evidence supporting the beneficial role of mucosal innate and effector T cell responses on EAEC burden and suggest pharmacological blockade of PPARγ as a novel therapeutic intervention for EAEC infection.</p> </div

    Early beneficial effects of PPARγ deficiency in T cells during enteroaggregative Escherichia coli (EAEC) challenge.

    No full text
    <p>Growth retardation in wild type (A) and T cell specific PPARγ deficient mice (B) is expressed as percent growth from day 0 after challenge. Gene expression for IL-6 and TNF-α in colonic tissue of malnourished C57BL/6 and PPARγ CD4cre+ mice was analyzed using quantitative real-time RT-PCR on day 5 PI (C). Representative photomicrographs of colonic specimens of infected mice at 5 or 14 days PI in infected wild type mice (D,E,I,J), infected mice lacking PPARγ expression in T cells (F,G,K,L), and uninfected controls (H,M). The top panel corresponds to nourished mice whereas the bottom panel corresponds to malnourished mice. Original magnification 200×. Boxes and arrows are areas where an amplified image (400×) is provided to emphasize examples of leukocyte infiltration, mucosal thickening, goblet cell hyperplasia, and vasodilation. Mice per group: n = 8. Asterisks indicate values where differences are statistically significant (<i>p</i><0.05).</p

    Neutralization of IL-17 abrogates the beneficial effects of GW9662 on weight loss and bacterial burden.

    No full text
    <p>Growth retardation in infected wild type mice is expressed as percent growth from day 0 after challenge (A). Enteroaggregative <i>Escherichia coli</i> (EAEC) burden in the colon was assessed by quantitative real time RT-PCR using bacterial DNA isolated from feces of infected mice treated with 1 µM PPARγ antagonist GW9662 (n = 3), 50 µg anti-IL17 and 1 µM GW9662 combined (n = 3) or untreated (n = 3). Asterisks indicate values where differences are statistically significant (<i>p</i><0.05), NS signifies no significant difference, and bars are present to indicate significance between groups.</p

    Pattern recognition receptors are differentially regulated by <i>Helicobacter pylori</i>.

    No full text
    <p>Genes involved in pathogen detection were extracted from the RNAseq dataset and analyzed at each time point for significance (A; left–expression, right–significance). Expression of effector PRRs conformed to sustained or late waves whereas regulatory molecules were suppressed (B). Dynamic expression of transcripts observed by RNAseq was validated by quantitative real time RT-PCR (C). Transcriptomic data (A,B) are presented as average log2(ratio) whereas validation gene expression is presented as pg cDNA/500ug RNA. Asterisk indicates <i>P</i>-value < 0.05 based on ANOVA.</p

    Intracellular <i>Helicobacter pylori</i> induces temporal waves in macrophage immunity.

    No full text
    <p>Clustering analysis was performed on differentially expressed genes (FDR p-value <0.05) obtained from RNAseq performed on macrophages co-cultured with <i>H</i>. <i>pylori</i>. Values are presented as the log2 (ratio) of average infected (n = 3) to average non-infected (n = 3) for each time point (0, 60, 120, 240, 360 and 720 min post-co-culture). Transcripts were grouped into 12 gene-modules based on expression levels and temporal behavior. Gene expression profiles for each cluster are plotted with representative members (M) and similarities in function identified by Gene Ontology (GO).</p

    Systems Modeling of Molecular Mechanisms Controlling Cytokine-driven CD4+ T Cell Differentiation and Phenotype Plasticity

    Get PDF
    <div><p>Differentiation of CD4+ T cells into effector or regulatory phenotypes is tightly controlled by the cytokine milieu, complex intracellular signaling networks and numerous transcriptional regulators. We combined experimental approaches and computational modeling to investigate the mechanisms controlling differentiation and plasticity of CD4+ T cells in the gut of mice. Our computational model encompasses the major intracellular pathways involved in CD4+ T cell differentiation into T helper 1 (Th1), Th2, Th17 and induced regulatory T cells (iTreg). Our modeling efforts predicted a critical role for peroxisome proliferator-activated receptor gamma (PPARγ) in modulating plasticity between Th17 and iTreg cells. PPARγ regulates differentiation, activation and cytokine production, thereby controlling the induction of effector and regulatory responses, and is a promising therapeutic target for dysregulated immune responses and inflammation. Our modeling efforts predict that following PPARγ activation, Th17 cells undergo phenotype switch and become iTreg cells. This prediction was validated by results of adoptive transfer studies showing an increase of colonic iTreg and a decrease of Th17 cells in the gut mucosa of mice with colitis following pharmacological activation of PPARγ. Deletion of PPARγ in CD4+ T cells impaired mucosal iTreg and enhanced colitogenic Th17 responses in mice with CD4+ T cell-induced colitis. Thus, for the first time we provide novel molecular evidence <i>in vivo</i> demonstrating that PPARγ in addition to regulating CD4+ T cell differentiation also plays a major role controlling Th17 and iTreg plasticity in the gut mucosa.</p></div

    Network model illustrating the complex intracellular signaling pathways and transcriptional factors controlling the CD4+ T cell differentiation process.

    No full text
    <p>The signaling network illustrates network topologies associated with differentiation towards T helper (Th)1 (red shadow), Th2 (green shadow), Th17 (blue shadow) and induced regulatory T cells (iTreg, yellow shadow). The network is provided in Systems Biology Markup Language-compliant format.</p
    corecore