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Calprotectin Increases the Activity of the SaeRS Two Component System and Murine Mortality during Staphylococcus aureus Infections.

Cho H, Jeong DW, Liu Q, Yeo WS, Vogl T, Skaar EP, Chazin WJ, Bae T - PLoS Pathog. (2015)

Bottom Line: Here we show that calprotectin can also enhance the activity of the SaeRS two component system (TCS), a signaling system essential for production of over 20 virulence factors in S. aureus.During staphylococcal encounter with murine neutrophils or staphylococcal infection of the murine peritoneal cavity, calprotectin increases the activity of the SaeRS TCS as well as the production of proinflammatory cytokines such as IL-1β and TNF-α, resulting in higher murine mortality.These results suggest that, under certain conditions, calprotectin can be exploited by S. aureus to increase bacterial virulence and host mortality.

View Article: PubMed Central - PubMed

Affiliation: Indiana University School of Medicine-Northwest, Gary, Indiana, United States of America.

ABSTRACT
Calprotectin, the most abundant cytoplasmic protein in neutrophils, suppresses the growth of Staphylococcus aureus by sequestering the nutrient metal ions Zn and Mn. Here we show that calprotectin can also enhance the activity of the SaeRS two component system (TCS), a signaling system essential for production of over 20 virulence factors in S. aureus. The activity of the SaeRS TCS is repressed by certain divalent ions found in blood or neutrophil granules; however, the Zn bound-form of calprotectin relieves this repression. During staphylococcal encounter with murine neutrophils or staphylococcal infection of the murine peritoneal cavity, calprotectin increases the activity of the SaeRS TCS as well as the production of proinflammatory cytokines such as IL-1β and TNF-α, resulting in higher murine mortality. These results suggest that, under certain conditions, calprotectin can be exploited by S. aureus to increase bacterial virulence and host mortality.

No MeSH data available.


Related in: MedlinePlus

CP is required for full activation of the SaeRS TCS and cytokine production by murine neutrophils.(A) Activation of the SaeRS TCS by neutrophils from C57BL/6 (WT) and C57BL/6 S100A9 -/- (A9-/-) mice. Neutrophils purified from bone marrow of WT or A9-/- mice were mixed with S. aureus strain USA300 containing P1-gfp reporter plasmid (MOI = 10). At the indicated time points, neutrophils were lysed, and the P1 promoter activity was measured by flow cytometry (top panel), and the results were also presented in a bar graph (bottom panel). In the flow cytometry analysis, gray color represents the results from the control plasmid (pCL-gfp). In the bar graph, error bars depict standard error of the mean. Results are from three pooled mice per genotype and represent three independent experiments. (B) The effect of CP in the cytokine production of neutrophil. Neutrophils purified from bone marrow of WT and S100A9-/- mice were infected with S. aureus USA300 (MOI = 10) for 2 h. After addition of gentamicin, neutrophils were further incubated for 16 h, and the concentration of the cytokines indicated was determined by ELISA. The data are from three pooled animals per genotype and representative of three independent experiments. Error bars indicate standard error of the mean. Statistical significance was determined by unpaired, two tailed t-test.
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ppat.1005026.g005: CP is required for full activation of the SaeRS TCS and cytokine production by murine neutrophils.(A) Activation of the SaeRS TCS by neutrophils from C57BL/6 (WT) and C57BL/6 S100A9 -/- (A9-/-) mice. Neutrophils purified from bone marrow of WT or A9-/- mice were mixed with S. aureus strain USA300 containing P1-gfp reporter plasmid (MOI = 10). At the indicated time points, neutrophils were lysed, and the P1 promoter activity was measured by flow cytometry (top panel), and the results were also presented in a bar graph (bottom panel). In the flow cytometry analysis, gray color represents the results from the control plasmid (pCL-gfp). In the bar graph, error bars depict standard error of the mean. Results are from three pooled mice per genotype and represent three independent experiments. (B) The effect of CP in the cytokine production of neutrophil. Neutrophils purified from bone marrow of WT and S100A9-/- mice were infected with S. aureus USA300 (MOI = 10) for 2 h. After addition of gentamicin, neutrophils were further incubated for 16 h, and the concentration of the cytokines indicated was determined by ELISA. The data are from three pooled animals per genotype and representative of three independent experiments. Error bars indicate standard error of the mean. Statistical significance was determined by unpaired, two tailed t-test.

Mentions: To investigate the role of CP in the activation of the SaeRS TCS by neutrophils, we generated a GFP reporter system for the P1 promoter and integrated it in the chromosome of the strain USA300 (S1A Fig). The resulting reporter strain showed significantly higher GFP signal, as compared with no-promoter control (S3B Fig), and responded to the repression by Fe and Zn (S3C Fig). When the reporter strain was mixed with murine neutrophils purified from either wild type or CP-deficient mice, a higher GFP signal was observed in the presence of wild type neutrophils at 4 h post incubation, and it was more pronounced at 16 h (Fig 5A), suggesting that CP indeed contributes to the activation of the SaeRS TCS during encounter with murine neutrophils.


Calprotectin Increases the Activity of the SaeRS Two Component System and Murine Mortality during Staphylococcus aureus Infections.

Cho H, Jeong DW, Liu Q, Yeo WS, Vogl T, Skaar EP, Chazin WJ, Bae T - PLoS Pathog. (2015)

CP is required for full activation of the SaeRS TCS and cytokine production by murine neutrophils.(A) Activation of the SaeRS TCS by neutrophils from C57BL/6 (WT) and C57BL/6 S100A9 -/- (A9-/-) mice. Neutrophils purified from bone marrow of WT or A9-/- mice were mixed with S. aureus strain USA300 containing P1-gfp reporter plasmid (MOI = 10). At the indicated time points, neutrophils were lysed, and the P1 promoter activity was measured by flow cytometry (top panel), and the results were also presented in a bar graph (bottom panel). In the flow cytometry analysis, gray color represents the results from the control plasmid (pCL-gfp). In the bar graph, error bars depict standard error of the mean. Results are from three pooled mice per genotype and represent three independent experiments. (B) The effect of CP in the cytokine production of neutrophil. Neutrophils purified from bone marrow of WT and S100A9-/- mice were infected with S. aureus USA300 (MOI = 10) for 2 h. After addition of gentamicin, neutrophils were further incubated for 16 h, and the concentration of the cytokines indicated was determined by ELISA. The data are from three pooled animals per genotype and representative of three independent experiments. Error bars indicate standard error of the mean. Statistical significance was determined by unpaired, two tailed t-test.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4492782&req=5

ppat.1005026.g005: CP is required for full activation of the SaeRS TCS and cytokine production by murine neutrophils.(A) Activation of the SaeRS TCS by neutrophils from C57BL/6 (WT) and C57BL/6 S100A9 -/- (A9-/-) mice. Neutrophils purified from bone marrow of WT or A9-/- mice were mixed with S. aureus strain USA300 containing P1-gfp reporter plasmid (MOI = 10). At the indicated time points, neutrophils were lysed, and the P1 promoter activity was measured by flow cytometry (top panel), and the results were also presented in a bar graph (bottom panel). In the flow cytometry analysis, gray color represents the results from the control plasmid (pCL-gfp). In the bar graph, error bars depict standard error of the mean. Results are from three pooled mice per genotype and represent three independent experiments. (B) The effect of CP in the cytokine production of neutrophil. Neutrophils purified from bone marrow of WT and S100A9-/- mice were infected with S. aureus USA300 (MOI = 10) for 2 h. After addition of gentamicin, neutrophils were further incubated for 16 h, and the concentration of the cytokines indicated was determined by ELISA. The data are from three pooled animals per genotype and representative of three independent experiments. Error bars indicate standard error of the mean. Statistical significance was determined by unpaired, two tailed t-test.
Mentions: To investigate the role of CP in the activation of the SaeRS TCS by neutrophils, we generated a GFP reporter system for the P1 promoter and integrated it in the chromosome of the strain USA300 (S1A Fig). The resulting reporter strain showed significantly higher GFP signal, as compared with no-promoter control (S3B Fig), and responded to the repression by Fe and Zn (S3C Fig). When the reporter strain was mixed with murine neutrophils purified from either wild type or CP-deficient mice, a higher GFP signal was observed in the presence of wild type neutrophils at 4 h post incubation, and it was more pronounced at 16 h (Fig 5A), suggesting that CP indeed contributes to the activation of the SaeRS TCS during encounter with murine neutrophils.

Bottom Line: Here we show that calprotectin can also enhance the activity of the SaeRS two component system (TCS), a signaling system essential for production of over 20 virulence factors in S. aureus.During staphylococcal encounter with murine neutrophils or staphylococcal infection of the murine peritoneal cavity, calprotectin increases the activity of the SaeRS TCS as well as the production of proinflammatory cytokines such as IL-1β and TNF-α, resulting in higher murine mortality.These results suggest that, under certain conditions, calprotectin can be exploited by S. aureus to increase bacterial virulence and host mortality.

View Article: PubMed Central - PubMed

Affiliation: Indiana University School of Medicine-Northwest, Gary, Indiana, United States of America.

ABSTRACT
Calprotectin, the most abundant cytoplasmic protein in neutrophils, suppresses the growth of Staphylococcus aureus by sequestering the nutrient metal ions Zn and Mn. Here we show that calprotectin can also enhance the activity of the SaeRS two component system (TCS), a signaling system essential for production of over 20 virulence factors in S. aureus. The activity of the SaeRS TCS is repressed by certain divalent ions found in blood or neutrophil granules; however, the Zn bound-form of calprotectin relieves this repression. During staphylococcal encounter with murine neutrophils or staphylococcal infection of the murine peritoneal cavity, calprotectin increases the activity of the SaeRS TCS as well as the production of proinflammatory cytokines such as IL-1β and TNF-α, resulting in higher murine mortality. These results suggest that, under certain conditions, calprotectin can be exploited by S. aureus to increase bacterial virulence and host mortality.

No MeSH data available.


Related in: MedlinePlus