Salmonella manipulates the host to drive pathogenicity via induction of interleukin 1β [16S]
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ABSTRACT: Acute gastrointestinal infection with intracellular pathogens like Salmonella Typhimurium triggers the release of the proinflammatory cytokine interleukin 1β (IL-1β). However, the role of IL-1β in intestinal defense against Salmonella remains unclear. Here, we show that IL-1b production is detrimental during Salmonella infection. Mice lacking IL-1b (IL-1b -/-) failed to recruit neutrophils to the gut during infection, which reduced tissue damage and prevented depletion of short-chain fatty acid-producing commensals. Changes in epithelial cell metabolism that typically support pathogen expansion, such as switching energy production from fatty acid oxidation to fermentation, were absent in infected IL-1b -/- mice which inhibited Salmonella expansion. Additionally, we found that IL-1b induces expression of complement anaphylatoxins and suppresses the complement-inactivator Carboxypeptidase N (CPN1). Disrupting this process via IL-1b loss prevented mortality in Salmonella-infected IL-1b -/- mice. Finally, we found that IL-1b expression correlates with expression of the complement receptor in patients suffering from sepsis, but not uninfected patients and healthy individuals. Thus, Salmonella exploits IL-1b signaling to outcompete commensal microbes and establish gut colonization. Moreover, our findings identify the intersection of IL-1b signaling and the complement system as key host factors involved in controlling mortality during invasive Salmonellosis.
Project description:Acute gastrointestinal infection with intracellular pathogens like Salmonella Typhimurium triggers the release of the proinflammatory cytokine interleukin 1β (IL-1β). However, the role of IL-1β in intestinal defense against Salmonella remains unclear. Here, we show that IL-1b production is detrimental during Salmonella infection. Mice lacking IL-1b (IL-1b -/-) failed to recruit neutrophils to the gut during infection, which reduced tissue damage and prevented depletion of short-chain fatty acid-producing commensals. Changes in epithelial cell metabolism that typically support pathogen expansion, such as switching energy production from fatty acid oxidation to fermentation, were absent in infected IL-1b -/- mice which inhibited Salmonella expansion. Additionally, we found that IL-1b induces expression of complement anaphylatoxins and suppresses the complement-inactivator Carboxypeptidase N (CPN1). Disrupting this process via IL-1b loss prevented mortality in Salmonella-infected IL-1b -/- mice. Finally, we found that IL-1b expression correlates with expression of the complement receptor in patients suffering from sepsis, but not uninfected patients and healthy individuals. Thus, Salmonella exploits IL-1b signaling to outcompete commensal microbes and establish gut colonization. Moreover, our findings identify the intersection of IL-1b signaling and the complement system as key host factors involved in controlling mortality during invasive Salmonellosis.
Project description:Cytokines have been shown to play a key role in the destruction of beta cells. In the rat insulinoma cell line (INS-1ab) overexpressing pancreatic duodenum homeobox 1 (Pdx1) increases sensitivity to Interleukin 1b (IL-1b). To elucidate mechanisms of action underlying Pdx1 driven potentiation of beta-cell sensitivity to IL-1β, we performed a microarray analysis of INS-1ab cells with and without Pdx1 overexpression exposed to IL-1β between 2h and 24h. INS-1ab cells were cultured with or without 500 ng/ml doxycycline (+/- DOX). After 24 h, 40 ng/ml IL-1b was either added or not (+/- IL-1b). Cells were harvested either 2h, 4h, 6h, 12h or 24h after addition of IL-1b. Four biological replicates for each of the eight groups.
Project description:ILC2s regulate type2 immune responses and protect against helminth infection. We found that ILC2s can be expanded in the presence of a combination of cytokines IL-2 and IL-1b. To better understand the functional and phenotypic consequence of IL-1β activation of ILC2s, we utilized whole transcriptome sequencing (RNA-seq) of freshly isolated ILC2s and IL-1β-primed ILC2s. Differential expression analysis revealed a substantial number of genes underwent significant change between the two conditions (total 4,744 gene, FDR<0.01, Fold change >2), among which 3,871 genes were upregulated in IL-1β –primed ILC2s.
Project description:Hemachromatosis (iron-overload) increases host susceptibility to siderophilic bacterial infections that cause serious complications, but the underlying mechanisms remain elusive. The present study demonstrates that oral infection with hyper-yersiniabactin (Ybt) producing Yersinia pseudotuberculosis Δfur mutant (termed Δfur) results in severe systemic infection and acute mortality to hemochromatotic mice due to rapid disruption of the intestinal barrier. Transcriptome analysis of Δfur infected intestine revealed upregulation in cytokine-cytokine receptor interactions, the complement and coagulation cascade, the NF-κB signaling pathway, and chemokine signaling pathways, and downregulation in cell adhesion molecules and TLR signaling pathways. Further studies indicate that dysregulated IL-1b signaling triggered in hemachromatotic mice infected with Δfur damages the intestinal barrier by activation of myosin light chain kinases (MLCK) and excessive neutrophilia. Inhibiting MLCK activity or depleting neutrophil infiltration reduces barrier disruption, largely ameliorates immunopathology, and substantially rescues hemochromatotic mice from lethal Δfur infection. Moreover, early intervention of IL-1b overproduction can completely rescue hemochromatotic mice from the lethal infection.
Project description:Cytokines have been shown to play a key role in the destruction of beta cells. In the rat insulinoma cell line (INS-1ab) overexpressing pancreatic duodenum homeobox 1 (Pdx1) increases sensitivity to Interleukin 1b (IL-1b). To elucidate mechanisms of action underlying Pdx1 driven potentiation of beta-cell sensitivity to IL-1β, we performed a microarray analysis of INS-1ab cells with and without Pdx1 overexpression exposed to IL-1β between 2h and 24h.
Project description:Expression of interleukin-15 (IL-15) on the surface of human graft endothelial cells (ECs) bound to the IL-15 receptor a (IL-15Ra) subunit can increase the activation of cytotoxic T lymphocytes (CTLs), potentiating allograft rejection. Our previous work showed that surface expression of this protein complex could be induced by alloantibody-mediated complement activation through increased IL-1b synthesis, secretion, and autocrine/paracrine IL-1-mediated activation of NF-kB. Here we report that cultured human ECs express 8 differently spliced IL-15 transcripts. Remarkably, IL-1β does not alter the expression level of any IL-15 transcript but induces surface expression independently of RNA Polymerase II-mediated transcription while requiring new protein translation. Mechanistically, IL-1β causes an NF-kB-mediated reduction in the level of microRNA Let-7c-3p, thereby relieving a block of translation of IL-15 surface protein. Let7c-3p antimir can induce EC surface expression of IL-15/IL-15Ra in the absence of complement activation or of IL-1, enabling IL-15 trans-presentation to boost CD8 T cell activation. Because of the complexity we have uncovered in IL-15 regulation, we recommend caution in interpreting increased total IL-15 mRNA or protein levels as a surrogate for trans-presentation.
Project description:Expression of interleukin-15 (IL-15) on the surface of human graft endothelial cells (ECs) bound to the IL-15 receptor a (IL-15Ra) subunit can increase the activation of cytotoxic T lymphocytes (CTLs), potentiating allograft rejection. Our previous work showed that surface expression of this protein complex could be induced by alloantibody-mediated complement activation through increased IL-1b synthesis, secretion, and autocrine/paracrine IL-1-mediated activation of NF-kB. Here we report that cultured human ECs express 8 differently spliced IL-15 transcripts. Remarkably, IL-1β does not alter the expression level of any IL-15 transcript but induces surface expression independently of RNA Polymerase II-mediated transcription while requiring new protein translation. Mechanistically, IL-1β causes an NF-kB-mediated reduction in the level of microRNA Let-7c-3p, thereby relieving a block of translation of IL-15 surface protein. Let7c-3p antimir can induce EC surface expression of IL-15/IL-15Ra in the absence of complement activation or of IL-1, enabling IL-15 trans-presentation to boost CD8 T cell activation. Because of the complexity we have uncovered in IL-15 regulation, we recommend caution in interpreting increased total IL-15 mRNA or protein levels as a surrogate for trans-presentation.
Project description:Transcriptional profiling of mouse gut wall tissue following infection with Salmonella or treatment with Probiotics to see the role of probiotics in preventing salmonella infection through gut mucosal route of mouse.
Project description:We sought to develop and characterize a novel paucibacillary model in mice, which develop necrotic lung granulomas following infection with Mycobacterium tuberculosis. Paucibacillary infection was established, recapitulating the sterilizing activities of human LTBI regimens. TNF neutralization led to increased lung bacillary load, disrupted granuloma architecture with expanded necrotic foci and reduced tissue hypoxia, and accelerated animal mortality. TNF-neutralized mouse lungs and sera showed significant upregulation of IFNγ, IL-1β, IL-6, IL-10, CCL2, CCL3, and matrix metalloproteinase genes
Project description:Gut microbiota contributes to the regulation of host immune response and homeostasis. Bile acid (BA) derivatives from gut microbiota can affect the differentiation and function of the immune cells. However, it is incompletely clear for the regulation of BA metabolites in the macrophages. We here find that BA metabolites can regulate sensitivity of macrophages to LPS and or Gram-negative bacteria. BA derivatives could induce lncRNA57RIK expression through sphingosine-1-phosphate receptor 2 (S1PR2) in the macrophages of mice and humans, which play a critical role in Gram-negative bacteria mediated IL-1β maturation and pyroptosis of macrophages. This lncRNA57RIK could bind intracellular proteases caspase-4/11 with guanylate-binding protein 1 (GBP1) in the human and mice together to cause LPS mediated activation of caspase-4/11. Murine or human lncRNA57RIK knockout (KO) macrophages did not produce response(s) to LPS or gram negative bacteria. LncRNA57RIK KO mice had also reduced inflammatory responses to LPS or Salmonella typhimurium (S.T) infection. Taken together, gut microbiota derived BA metabolites mediated lncRNA57RIK is necessary for LPS induced caspase-4/11 activation.