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The PagN protein of Salmonella enterica serovar Typhimurium is an adhesin and invasin.

Lambert MA, Smith SG - BMC Microbiol. (2008)

Bottom Line: S. enterica sv Typhimurium pagN mutants display a reduction in adhesion to and invasion of epithelial cells.Typhimurium.Finally PagN can be added to an ever-growing repertoire of factors that contribute to the pathogenesis of Salmonella.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Clinical Microbiology, Trinity College Dublin, St James's Hospital, Dublin 8, Ireland. malamber79@gmail.com

ABSTRACT

Background: The pagN gene of Salmonella enterica serovar Typhimurium is a PhoP-regulated gene that is up-regulated during growth within macrophages and in vivo in murine models of infection. The PagN protein displays similarity to the Hek and Tia invasins/adhesins of Escherichia coli. Thus far no function has been ascribed to the PagN protein.

Results: Here we show that the outer membrane located PagN protein mediates agglutination of red blood cells and that this can be masked by LPS. When expressed in Escherichia coli the PagN protein supports adhesion to and invasion of mammalian cells in a manner that is dependent on cytoskeletal rearrangements. S. enterica sv Typhimurium pagN mutants display a reduction in adhesion to and invasion of epithelial cells. Finally, we demonstrate that over-expression of PagN in a SPI-1 mutant can partially compensate for the lack of a functional invasasome.

Conclusion: PagN is an outer membrane protein that may contribute to the virulence of S. Typhimurium. This protein is a haemagglutinin and contributes to the adherence to mammalian cells. In addition, PagN can mediate high-level invasion of CHO-K1 cells. Previously,pagN mutants have been shown to be less competitive in vivo and thus this may be due to their lessened ability to interact with mammalian cells. Finally PagN can be added to an ever-growing repertoire of factors that contribute to the pathogenesis of Salmonella.

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PagN-promoted invasion of epithelial cells requires actin polymerisation. E. coli DH5α harboring either pTrc99a or pML1 were induced with IPTG and incubated with CHO-K1 cells and invasion levels were measured (black bars). To assess the role of actin filament polymerisation in PagN-mediated invasion, confluent CHO-K1 monolayers were pre-incubated with cytochalasin D (1 μg/ml) for 30 min at 37°C before infection with bacteria (grey bars).
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Figure 2: PagN-promoted invasion of epithelial cells requires actin polymerisation. E. coli DH5α harboring either pTrc99a or pML1 were induced with IPTG and incubated with CHO-K1 cells and invasion levels were measured (black bars). To assess the role of actin filament polymerisation in PagN-mediated invasion, confluent CHO-K1 monolayers were pre-incubated with cytochalasin D (1 μg/ml) for 30 min at 37°C before infection with bacteria (grey bars).

Mentions: Given that PagN has similarity to both the Tia and Hek invasins we determined if PagN could mediate adhesion to and invasion of epithelial cells. E. coli DH5α harboring either pTrc99a or pML1 were induced with IPTG and incubated with CHO-K1 cells. To enumerate the number of invading bacteria, a gentamicin protection assay was performed. Approximately 60% of PagN-expressing bacteria invaded the CHO-K1 cells. Indeed, bacteria that expressed PagN were 27-fold more invasive than bacteria harboring the vector control plasmid (Fig. 2).


The PagN protein of Salmonella enterica serovar Typhimurium is an adhesin and invasin.

Lambert MA, Smith SG - BMC Microbiol. (2008)

PagN-promoted invasion of epithelial cells requires actin polymerisation. E. coli DH5α harboring either pTrc99a or pML1 were induced with IPTG and incubated with CHO-K1 cells and invasion levels were measured (black bars). To assess the role of actin filament polymerisation in PagN-mediated invasion, confluent CHO-K1 monolayers were pre-incubated with cytochalasin D (1 μg/ml) for 30 min at 37°C before infection with bacteria (grey bars).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2553418&req=5

Figure 2: PagN-promoted invasion of epithelial cells requires actin polymerisation. E. coli DH5α harboring either pTrc99a or pML1 were induced with IPTG and incubated with CHO-K1 cells and invasion levels were measured (black bars). To assess the role of actin filament polymerisation in PagN-mediated invasion, confluent CHO-K1 monolayers were pre-incubated with cytochalasin D (1 μg/ml) for 30 min at 37°C before infection with bacteria (grey bars).
Mentions: Given that PagN has similarity to both the Tia and Hek invasins we determined if PagN could mediate adhesion to and invasion of epithelial cells. E. coli DH5α harboring either pTrc99a or pML1 were induced with IPTG and incubated with CHO-K1 cells. To enumerate the number of invading bacteria, a gentamicin protection assay was performed. Approximately 60% of PagN-expressing bacteria invaded the CHO-K1 cells. Indeed, bacteria that expressed PagN were 27-fold more invasive than bacteria harboring the vector control plasmid (Fig. 2).

Bottom Line: S. enterica sv Typhimurium pagN mutants display a reduction in adhesion to and invasion of epithelial cells.Typhimurium.Finally PagN can be added to an ever-growing repertoire of factors that contribute to the pathogenesis of Salmonella.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Clinical Microbiology, Trinity College Dublin, St James's Hospital, Dublin 8, Ireland. malamber79@gmail.com

ABSTRACT

Background: The pagN gene of Salmonella enterica serovar Typhimurium is a PhoP-regulated gene that is up-regulated during growth within macrophages and in vivo in murine models of infection. The PagN protein displays similarity to the Hek and Tia invasins/adhesins of Escherichia coli. Thus far no function has been ascribed to the PagN protein.

Results: Here we show that the outer membrane located PagN protein mediates agglutination of red blood cells and that this can be masked by LPS. When expressed in Escherichia coli the PagN protein supports adhesion to and invasion of mammalian cells in a manner that is dependent on cytoskeletal rearrangements. S. enterica sv Typhimurium pagN mutants display a reduction in adhesion to and invasion of epithelial cells. Finally, we demonstrate that over-expression of PagN in a SPI-1 mutant can partially compensate for the lack of a functional invasasome.

Conclusion: PagN is an outer membrane protein that may contribute to the virulence of S. Typhimurium. This protein is a haemagglutinin and contributes to the adherence to mammalian cells. In addition, PagN can mediate high-level invasion of CHO-K1 cells. Previously,pagN mutants have been shown to be less competitive in vivo and thus this may be due to their lessened ability to interact with mammalian cells. Finally PagN can be added to an ever-growing repertoire of factors that contribute to the pathogenesis of Salmonella.

Show MeSH
Related in: MedlinePlus