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Enterohemorrhagic Escherichia coli O157:H7 gene expression profiling in response to growth in the presence of host epithelia.

Jandu N, Ho NK, Donato KA, Karmali MA, Mascarenhas M, Duffy SP, Tailor C, Sherman PM - PLoS ONE (2009)

Bottom Line: Total RNA was then extracted and used for microarray analyses (Affymetrix E. coli Genome 2.0 gene chips).Microarray analyses and gene deletion identified a protease on O-island 50, gene Z1787, as a potential virulence factor responsible for mediating EHEC inhibition of the interferon (IFN)-gamma-Jak1,2-STAT-1 signal transduction cascade.Up-regulated genes provide novel targets for use in developing strategies to interrupt the infectious process.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.

ABSTRACT

Background: The pathogenesis of enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection is attributed to virulence factors encoded on multiple pathogenicity islands. Previous studies have shown that EHEC O157:H7 modulates host cell signal transduction cascades, independent of toxins and rearrangement of the cytoskeleton. However, the virulence factors and mechanisms responsible for EHEC-mediated subversion of signal transduction remain to be determined. Therefore, the purpose of this study was to first identify differentially regulated genes in response to EHEC O157:H7 grown in the presence of epithelial cells, compared to growth in the absence of epithelial cells (that is, growth in minimal essential tissue culture medium alone, minimal essential tissue culture medium in the presence of 5% CO(2), and Penassay broth alone) and, second, to identify EHEC virulence factors responsible for pathogen modulation of host cell signal transduction.

Methodology/principal findings: Overnight cultures of EHEC O157:H7 were incubated for 6 hr at 37 degrees C in the presence or absence of confluent epithelial (HEp-2) cells. Total RNA was then extracted and used for microarray analyses (Affymetrix E. coli Genome 2.0 gene chips). Relative to bacteria grown in each of the other conditions, EHEC O157:H7 cultured in the presence of cultured epithelial cells displayed a distinct gene-expression profile. A 2.0-fold increase in the expression of 71 genes and a 2.0-fold decrease in expression of 60 other genes were identified in EHEC O157:H7 grown in the presence of epithelial cells, compared to bacteria grown in media alone.

Conclusion/significance: Microarray analyses and gene deletion identified a protease on O-island 50, gene Z1787, as a potential virulence factor responsible for mediating EHEC inhibition of the interferon (IFN)-gamma-Jak1,2-STAT-1 signal transduction cascade. Up-regulated genes provide novel targets for use in developing strategies to interrupt the infectious process.

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Related in: MedlinePlus

Functional classification of the 131 differentially regulated genes during EHEC O157∶H7 growth in the presence of epithelial cells, relative to the absence of epithelial cells, as summarized in a pie chart [27].Each pie slice represents a major functional group of genes. Numbers shown represent percentage.
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pone-0004889-g003: Functional classification of the 131 differentially regulated genes during EHEC O157∶H7 growth in the presence of epithelial cells, relative to the absence of epithelial cells, as summarized in a pie chart [27].Each pie slice represents a major functional group of genes. Numbers shown represent percentage.

Mentions: Differentially regulated genes were categorized using a previously described functional classification system [21], [26]. As shown in Figure 3 [27], the majority of the gene changes were clustered in the functional group comprising genes which encode for transport and binding proteins (8.4%), energy metabolism factors (11.5%), central intermediary metabolism factors (6.9%), and factors involved in cellular processes (10.7%). The next set of functional groups displaying the greatest gene expression changes in relation to EHEC O157∶H7 growth conditions were those encoding macromolecule biosynthesis (amino acid biosynthesis: 3.5%; biosynthesis of cofactors: 0.8%; carbon compound biosynthesis: 3.1%), cell structure components (3.8%), regulatory components (0.8%), and putative factors (0.8–11.5%). As in most microarrays, hypothetical proteins or genes of unknown function accounted for the greatest percentage (23.7%) of all differentially regulated genes in each comparison.


Enterohemorrhagic Escherichia coli O157:H7 gene expression profiling in response to growth in the presence of host epithelia.

Jandu N, Ho NK, Donato KA, Karmali MA, Mascarenhas M, Duffy SP, Tailor C, Sherman PM - PLoS ONE (2009)

Functional classification of the 131 differentially regulated genes during EHEC O157∶H7 growth in the presence of epithelial cells, relative to the absence of epithelial cells, as summarized in a pie chart [27].Each pie slice represents a major functional group of genes. Numbers shown represent percentage.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2654852&req=5

pone-0004889-g003: Functional classification of the 131 differentially regulated genes during EHEC O157∶H7 growth in the presence of epithelial cells, relative to the absence of epithelial cells, as summarized in a pie chart [27].Each pie slice represents a major functional group of genes. Numbers shown represent percentage.
Mentions: Differentially regulated genes were categorized using a previously described functional classification system [21], [26]. As shown in Figure 3 [27], the majority of the gene changes were clustered in the functional group comprising genes which encode for transport and binding proteins (8.4%), energy metabolism factors (11.5%), central intermediary metabolism factors (6.9%), and factors involved in cellular processes (10.7%). The next set of functional groups displaying the greatest gene expression changes in relation to EHEC O157∶H7 growth conditions were those encoding macromolecule biosynthesis (amino acid biosynthesis: 3.5%; biosynthesis of cofactors: 0.8%; carbon compound biosynthesis: 3.1%), cell structure components (3.8%), regulatory components (0.8%), and putative factors (0.8–11.5%). As in most microarrays, hypothetical proteins or genes of unknown function accounted for the greatest percentage (23.7%) of all differentially regulated genes in each comparison.

Bottom Line: Total RNA was then extracted and used for microarray analyses (Affymetrix E. coli Genome 2.0 gene chips).Microarray analyses and gene deletion identified a protease on O-island 50, gene Z1787, as a potential virulence factor responsible for mediating EHEC inhibition of the interferon (IFN)-gamma-Jak1,2-STAT-1 signal transduction cascade.Up-regulated genes provide novel targets for use in developing strategies to interrupt the infectious process.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.

ABSTRACT

Background: The pathogenesis of enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection is attributed to virulence factors encoded on multiple pathogenicity islands. Previous studies have shown that EHEC O157:H7 modulates host cell signal transduction cascades, independent of toxins and rearrangement of the cytoskeleton. However, the virulence factors and mechanisms responsible for EHEC-mediated subversion of signal transduction remain to be determined. Therefore, the purpose of this study was to first identify differentially regulated genes in response to EHEC O157:H7 grown in the presence of epithelial cells, compared to growth in the absence of epithelial cells (that is, growth in minimal essential tissue culture medium alone, minimal essential tissue culture medium in the presence of 5% CO(2), and Penassay broth alone) and, second, to identify EHEC virulence factors responsible for pathogen modulation of host cell signal transduction.

Methodology/principal findings: Overnight cultures of EHEC O157:H7 were incubated for 6 hr at 37 degrees C in the presence or absence of confluent epithelial (HEp-2) cells. Total RNA was then extracted and used for microarray analyses (Affymetrix E. coli Genome 2.0 gene chips). Relative to bacteria grown in each of the other conditions, EHEC O157:H7 cultured in the presence of cultured epithelial cells displayed a distinct gene-expression profile. A 2.0-fold increase in the expression of 71 genes and a 2.0-fold decrease in expression of 60 other genes were identified in EHEC O157:H7 grown in the presence of epithelial cells, compared to bacteria grown in media alone.

Conclusion/significance: Microarray analyses and gene deletion identified a protease on O-island 50, gene Z1787, as a potential virulence factor responsible for mediating EHEC inhibition of the interferon (IFN)-gamma-Jak1,2-STAT-1 signal transduction cascade. Up-regulated genes provide novel targets for use in developing strategies to interrupt the infectious process.

Show MeSH
Related in: MedlinePlus