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Isolation, Characterization and Biological Properties of Membrane Vesicles Produced by the Swine Pathogen Streptococcus suis.

Haas B, Grenier D - PLoS ONE (2015)

Bottom Line: In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material.A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors.MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier.

View Article: PubMed Central - PubMed

Affiliation: Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire, Université Laval, Quebec City, QC, Canada.

ABSTRACT
Streptococcus suis, more particularly serotype 2, is a major swine pathogen and an emerging zoonotic agent worldwide that mainly causes meningitis, septicemia, endocarditis, and pneumonia. Although several potential virulence factors produced by S. suis have been identified in the last decade, the pathogenesis of S. suis infections is still not fully understood. In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material. A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors. Biological assays confirmed that S. suis MVs possess active subtilisin-like protease (SspA) and DNase (SsnA). S. suis MVs degraded neutrophil extracellular traps, a property that may contribute to the ability of the bacterium to escape the host defense response. MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier. The present study brought evidence that S. suis MVs may play a role as a virulence factor in the pathogenesis of S. suis infections, and given their composition be an excellent candidate for vaccine development.

No MeSH data available.


Related in: MedlinePlus

Quantification of NF-κB activation in U937-3xκB-LUC monocytes (A) and macrophage-like cells (B) by S. suis membrane vesicles (0.01 to 40 μg/ml), E. coli LPS (10 μg/ml), and S. suis P1/7 whole bacteria (MOI = 100).Results were considered significant at §: p < 0.05, *: p < 0.01, and #: p < 0.001 compared to unstimulated cells.
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pone.0130528.g005: Quantification of NF-κB activation in U937-3xκB-LUC monocytes (A) and macrophage-like cells (B) by S. suis membrane vesicles (0.01 to 40 μg/ml), E. coli LPS (10 μg/ml), and S. suis P1/7 whole bacteria (MOI = 100).Results were considered significant at §: p < 0.05, *: p < 0.01, and #: p < 0.001 compared to unstimulated cells.

Mentions: To explore the potential contribution of MVs to the inflammatory process associated with S. suis infections such as meningitis, NF-κB activition was monitored in monocytes and macrophages transfected with a luciferase reporter gene. NF-κB was dose-dependently activated by MVs following a 6-h stimulation of the monocytes and PMA-differentiated macrophages (Fig 5). More specifically, in the presence of 0.02 μg/ml (protein content) of MVs, NF-κB activity increased 2- and 2.5-fold compared to unstimulated monocytes and macrophage-like cells, respectively. In the presence of 40 μg/ml (protein content) MVs, NF-κB activity in monocytes and macrophages increased 137- and 82-fold, respectively, while S. suis P1/7 whole cells at an MOI of 100 increased NF-κB activity by approximately 10-fold in both monocytes and macrophage-like cells. Used as a positive control, E. coli LPS (10 μg/ml), which is a strong pro-inflammatory inducer, caused a 100- and 60-fold increase in NF-κB activity in monocytes and macrophages, respectively.


Isolation, Characterization and Biological Properties of Membrane Vesicles Produced by the Swine Pathogen Streptococcus suis.

Haas B, Grenier D - PLoS ONE (2015)

Quantification of NF-κB activation in U937-3xκB-LUC monocytes (A) and macrophage-like cells (B) by S. suis membrane vesicles (0.01 to 40 μg/ml), E. coli LPS (10 μg/ml), and S. suis P1/7 whole bacteria (MOI = 100).Results were considered significant at §: p < 0.05, *: p < 0.01, and #: p < 0.001 compared to unstimulated cells.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4482388&req=5

pone.0130528.g005: Quantification of NF-κB activation in U937-3xκB-LUC monocytes (A) and macrophage-like cells (B) by S. suis membrane vesicles (0.01 to 40 μg/ml), E. coli LPS (10 μg/ml), and S. suis P1/7 whole bacteria (MOI = 100).Results were considered significant at §: p < 0.05, *: p < 0.01, and #: p < 0.001 compared to unstimulated cells.
Mentions: To explore the potential contribution of MVs to the inflammatory process associated with S. suis infections such as meningitis, NF-κB activition was monitored in monocytes and macrophages transfected with a luciferase reporter gene. NF-κB was dose-dependently activated by MVs following a 6-h stimulation of the monocytes and PMA-differentiated macrophages (Fig 5). More specifically, in the presence of 0.02 μg/ml (protein content) of MVs, NF-κB activity increased 2- and 2.5-fold compared to unstimulated monocytes and macrophage-like cells, respectively. In the presence of 40 μg/ml (protein content) MVs, NF-κB activity in monocytes and macrophages increased 137- and 82-fold, respectively, while S. suis P1/7 whole cells at an MOI of 100 increased NF-κB activity by approximately 10-fold in both monocytes and macrophage-like cells. Used as a positive control, E. coli LPS (10 μg/ml), which is a strong pro-inflammatory inducer, caused a 100- and 60-fold increase in NF-κB activity in monocytes and macrophages, respectively.

Bottom Line: In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material.A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors.MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier.

View Article: PubMed Central - PubMed

Affiliation: Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire, Université Laval, Quebec City, QC, Canada.

ABSTRACT
Streptococcus suis, more particularly serotype 2, is a major swine pathogen and an emerging zoonotic agent worldwide that mainly causes meningitis, septicemia, endocarditis, and pneumonia. Although several potential virulence factors produced by S. suis have been identified in the last decade, the pathogenesis of S. suis infections is still not fully understood. In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material. A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors. Biological assays confirmed that S. suis MVs possess active subtilisin-like protease (SspA) and DNase (SsnA). S. suis MVs degraded neutrophil extracellular traps, a property that may contribute to the ability of the bacterium to escape the host defense response. MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier. The present study brought evidence that S. suis MVs may play a role as a virulence factor in the pathogenesis of S. suis infections, and given their composition be an excellent candidate for vaccine development.

No MeSH data available.


Related in: MedlinePlus