Unknown,Transcriptomics,Genomics,Proteomics

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Expression data from human neutrophils exposed to uropathogenic and commensal Esherichia coli.

ABSTRACT: The establishment of bacterial infections at epithelial surfaces is determined by the balance of virulence attributes of the pathogen with the activity of innate host defenses. Polymorphonuclear leukocytes (PMN) are key responders in many bacterial infections, but the mechanisms by which pathogens subvert these early responses to establish infection are largely undefined. Here, we model these early interactions between human PMN and the primary cause of urinary tract infections, namely uropathogenic Escherichia coli (UPEC). Our objective was to define virulence phenotypes of uropathogens (as compared with laboratory and commensal E. coli strains) that permit evasion of PMN activity. We found that UPEC strains resist phagocytic killing and dampen the production of antimicrobial reactive oxygen species by PMNs. Analysis of the global transcriptional responses of PMN to E. coli strains revealed that UPEC exposure downregulates the expression of PMN genes involved in proinflammatory signaling and PMN chemotaxis, adhesion, and migration. Consistent with these data, UPEC attenuated transepithelial neutrophil recruitment in an in vitro model of acute infection. We propose that these UPEC strategies are important in the establishment of epithelial infection, and that the findings are germane to a range of bacterial infections at epithelial surfaces. We used microarrays to detail the global program of gene expression in human neutrophils in response to a uropathogenic bacteria compared to a closely related non-pathogenic strain relative to control samples with no bacteria. Our goal was to elucidate a pathogen-specific response. We chose an early time point of 60 minutes to evaluate the accute response to infection. Human neutrophils were exposed to pathogenic or commensal Escherichia coli for RNA extraction and hybridization on Affymetrix microarrays

ORGANISM(S): Homo sapiens

SUBMITTER: Rekha Meyer

PROVIDER: E-GEOD-18810 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Ascending bacterial infections of the male genitourinary tract by Escherichia coli are an important cause of male infertility. Thus understanding mechanisms by which immunocompetent cells such as testicular macrophages (TM) respond to infection and how bacterial pathogens manipulate defense pathways is of great relevance. Following infection with uropathogenic E. coli (UPEC) whole genome expression profiling revealed induction of the calcium-dependent nuclear factor of activated T cells (NFAT) signaling pathway in TM as well as in peritoneal macrophages (PM) that were used in comparison. UPEC-dependent NFAT activation was confirmed in cultured TM and in TM using an in vivo infection model. Elevated expression of NFATC2-regulated anti-inflammatory cytokines was found in TM (IL-4, IL-13) and PM (IL-3, IL-4, IL-13). NFATC2 is activated by a rapid influx of calcium caused by the UPEC pore forming toxin alpha-hemolysin. Mutant analysis identified alpha-hemolysin as the main virulent factor responsible for UPEC-dependant suppression of IL-6 and TNF-a cytokine release from PM. Alpha-hemolysin caused differential activation of MAP kinase and AP-1 signaling pathways in TM and PM leading to differential expression profiles of key pro-inflammatory cytokines in PM (IL-1a, IL-1b and IL-6 downregulated) and TM (IL-1b and IL-6 upregulated). In contrast to PM, treatment with lipopolysaccharide did not result in activation of the NFkB pathway in TM as shown by lack of degradation of IkBa and lack of pro-inflammatory cytokine secretion (IL-6, TNF-a). In conclusion, these results propose a mechanism how TM can defend against microbes, while at the same time they are able to maintain the immune privileged status of the testis. 2 Macrophage populations ( peritoneal, testicular) infected with UPEC CFT073; timepoints of mrna harvest at 0 min (control), 30 min and 60 min; of each point 2 biological replicates; of each repliccate 2 technical replicates: summa summarum: 2*((1+1+1)*2*2)=24 samples

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Expression data from human neutrophils exposed to uropathogenic and commensal Esherichia coli.

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