Dataset Information

Modulation of the NF-kappaB pathway by Bordetella pertussis filamentous hemagglutinin.

ABSTRACT:

Background

Filamentous hemagglutinin (FHA) is a cell-associated and secreted adhesin produced by Bordetella pertussis with pro-apoptotic and pro-inflammatory activity in host cells. Given the importance of the NF-kappaB transcription factor family in these host cell responses, we examined the effect of FHA on NF-kappaB activation in macrophages and bronchial epithelial cells, both of which are relevant cell types during natural infection.

Methodology/principal findings

Exposure to FHA of primary human monocytes and transformed U-937 macrophages, but not BEAS-2B epithelial cells, resulted in early activation of the NF-kappaB pathway, as manifested by the degradation of cytosolic IkappaB alpha, by NF-kappaB DNA binding, and by the subsequent secretion of NF-kappaB-regulated inflammatory cytokines. However, exposure of macrophages and human monocytes to FHA for two hours or more resulted in the accumulation of cytosolic IkappaB alpha, and the failure of TNF-alpha to activate NF-kappaB. Proteasome activity was attenuated following exposure of cells to FHA for 2 hours, as was the nuclear translocation of RelA in BEAS-2B cells.

Conclusions

These results reveal a complex temporal dynamic, and suggest that despite short term effects to the contrary, longer exposures of host cells to this secreted adhesin may block NF-kappaB activation, and perhaps lead to a compromised immune response to this bacterial pathogen.

SUBMITTER: Abramson T

PROVIDER: S-EPMC2584786 | biostudies-literature | 2008

REPOSITORIES: biostudies-literature

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Publications

Modulation of the NF-kappaB pathway by Bordetella pertussis filamentous hemagglutinin.

Abramson Tzvia T Kedem Hassya H Relman David A DA

PloS one 20081127 11

<h4>Background</h4>Filamentous hemagglutinin (FHA) is a cell-associated and secreted adhesin produced by Bordetella pertussis with pro-apoptotic and pro-inflammatory activity in host cells. Given the importance of the NF-kappaB transcription factor family in these host cell responses, we examined the effect of FHA on NF-kappaB activation in macrophages and bronchial epithelial cells, both of which are relevant cell types during natural infection.<h4>Methodology/principal findings</h4>Exposure to ...[more]

PMID: 19043589

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Project description:Filamentous hemagglutinin (FHA), Bordetella pertussis' key adhesin, is both present at the cell surface and released in the extracellular milieu. To comprehend the role free FHA plays in the pathogenic process, we analyzed the global transcriptional changes in human peripheral blood mononuclear cells (PBMC) after exposure to that purified virulence factor. This analysis was undertaken with four different FHA preparations (FHA-1, FHA-2, FHA-3, and FHA-4), purified from four different B. pertussis strains. Cultures comprising 3x106 PBMC were stimulated for 0.5, 2, 4, and 6 hours with 5 ug/ml of each purified B. pertussis FHA. Control PBMC cultures were simultaneously treated with similar volumes of elution buffers (Mock-1 and Mock-2), and sampled at the same time points. The array experiment was composed of 27 samples. Most of the transcripts known to be part of the "common host-transcriptional response" that mediates inflammation were among the 1,235 array elements (representing 683 known unique genes) showing a greater than 3-fold change in transcript abundance between FHA-treated and untreated cells. We also identified an FHA-specific signature not observed in cells stimulated with B. pertussis LPS or heat-killed B. pertussis. This response, mounted by 13 genes, largely (69%, 9/13 genes) interferon (IFN)-regulated genes. Further analysis revealed that 18.3% (125 out of 683) of the FHA-responsive genes were in fact regulated by IFN. These included several major players of the antiviral IFN type I response, as well as three key components of the ISGylation pathway. Induction of the ubiquitin-like protein ISG15 and its specific protease USP18 was confirmed at the mRNA level by relative real-time polymerase chain reaction (RT-PCR). Western-blot analysis demonstrated the presence of both free ISG15 and several ISGylated conjugates in FHA-stimulated PBMC cell lysate. Intracellular FACS analysis provided further evidence that monocytes and a natural-killer (NK)-enriched cell population are the primary producers of ISG15 after FHA stimulation. Our results revealed new activities of free B. pertussis FHA: activation of the host IFN and ISGylation pathways. The consequences of such activation are yet to be resolved, but we hypothesize that FHA utilizes the ISGylation pathway or USP18 to regulate the IFN response, which in turn sensitizes the host to the infection and induces cell death. Groups of assays that are related as part of a time series. Infection: treatment with purified B. pertussis filamentous hemagglutinin (FHA) at 0.005 mg/mL Time: Samples were collected after various treatment time (hours) Keywords: time_series_design

Dataset Information

Modulation of the NF-kappaB pathway by Bordetella pertussis filamentous hemagglutinin.

Background

Methodology/principal findings

Conclusions

Publications

Modulation of the NF-kappaB pathway by Bordetella pertussis filamentous hemagglutinin.

Similar Datasets

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