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Protein kinase Cepsilon is required for macrophage activation and defense against bacterial infection.

Castrillo A, Pennington DJ, Otto F, Parker PJ, Owen MJ, Boscá L - J. Exp. Med. (2001)

Bottom Line: Macrophages from PKCepsilon(-/-) animals demonstrated a severely attenuated response to lipopolysaccharide (LPS) and interferon (IFN)gamma, characterized by a dramatic reduction in the generation of NO, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1beta.This study provides direct evidence that PKCepsilon is critically involved at an early stage of LPS-mediated signaling in activated macrophages.Furthermore, we demonstrate that in the absence of PKCepsilon, host defense against bacterial infection is severely compromised, resulting in an increased incidence of mortality.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Bioquímica (Centro Mixto Consejo Superior de Investigaciones Cientificas-UCM), Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain.

ABSTRACT
To assess directly the role of protein kinase C (PKC)epsilon in the immune system, we generated mice that carried a homozygous disruption of the PKCepsilon locus. PKCepsilon(-/-) animals appeared normal and were generally healthy, although female mice frequently developed a bacterial infection of the uterus. Macrophages from PKCepsilon(-/-) animals demonstrated a severely attenuated response to lipopolysaccharide (LPS) and interferon (IFN)gamma, characterized by a dramatic reduction in the generation of NO, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1beta. Further analysis revealed that LPS-stimulated macrophages from PKCepsilon(-/-) mice were deficient in the induction of nitric oxide synthase (NOS)-2, demonstrating a decrease in the activation of IkappaB kinase, a reduction in IkappaB degradation, and a decrease in nuclear factor (NF)kappaB nuclear translocation. After intravenous administration of Gram-negative or Gram-positive bacteria, PKCepsilon(-/-) mice demonstrated a significantly decreased period of survival. This study provides direct evidence that PKCepsilon is critically involved at an early stage of LPS-mediated signaling in activated macrophages. Furthermore, we demonstrate that in the absence of PKCepsilon, host defense against bacterial infection is severely compromised, resulting in an increased incidence of mortality.

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PKCε−/− mice are more sensitive to Gram-negative and Gram-positive bacterial challenge. Animals (n = 7–11 for each group) were injected intravenously with either (A) 3 × 105 or (B) 3 × 106 E. coli per gram of body weight, or (C) 3 × 105 S. aureus per gram of body weight. Survival of the mice was monitored for up to 20 d. Data were analyzed using the Kaplan-Meier plot. The * denotes P < 0.05 for experimental vs. wild-type survival times.
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fig7: PKCε−/− mice are more sensitive to Gram-negative and Gram-positive bacterial challenge. Animals (n = 7–11 for each group) were injected intravenously with either (A) 3 × 105 or (B) 3 × 106 E. coli per gram of body weight, or (C) 3 × 105 S. aureus per gram of body weight. Survival of the mice was monitored for up to 20 d. Data were analyzed using the Kaplan-Meier plot. The * denotes P < 0.05 for experimental vs. wild-type survival times.

Mentions: As female PKCε−/− mice displayed an unexpected incidence of uterine Gram-negative bacterial infection, and macrophages from PKCε−/− mice were demonstrated to have a severely attenuated response to LPS stimulation, it was hypothesized that PKCε-deficient animals would be more sensitive to Gram-negative bacteria than wild-type controls. To assess this possibility directly, a controlled E. coli bacterial infection was administered intravenously to both PKCε−/− and wild-type mice. At a bacterial dose of 3 × 105 pathogens per gram, ∼40% of the control animals survived for at least 20 d after infection. In contrast, all PKCε−/− mice had died by day 8 (median; 4.6 and 25.3 d for PKCε−/− and wild-type, respectively; Fig. 7 A). At the higher bacterial dose of 3 × 106 pathogens per gram, all animals from the wild-type group had died by day 3. However again, the PKCε−/− mice showed a decreased resistance to infection, as no animal survived beyond the first day (Fig. 7 B). Interestingly, when animals were injected with 3 × 105 Gram-positive S. aureus per gram of body weight, a difference in survival was also observed between PKCε−/− and wild-type animals (median; 6.8 and 21 d, respectively; Fig. 7 C). These results clearly demonstrate that mice deficient for PKCε are more sensitive to both Gram-negative and Gram-positive bacterial infection than wild-type controls, and that this increased sensitivity to infection can significantly decrease the likelihood of bacterial clearance and survival.


Protein kinase Cepsilon is required for macrophage activation and defense against bacterial infection.

Castrillo A, Pennington DJ, Otto F, Parker PJ, Owen MJ, Boscá L - J. Exp. Med. (2001)

PKCε−/− mice are more sensitive to Gram-negative and Gram-positive bacterial challenge. Animals (n = 7–11 for each group) were injected intravenously with either (A) 3 × 105 or (B) 3 × 106 E. coli per gram of body weight, or (C) 3 × 105 S. aureus per gram of body weight. Survival of the mice was monitored for up to 20 d. Data were analyzed using the Kaplan-Meier plot. The * denotes P < 0.05 for experimental vs. wild-type survival times.
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Related In: Results  -  Collection

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fig7: PKCε−/− mice are more sensitive to Gram-negative and Gram-positive bacterial challenge. Animals (n = 7–11 for each group) were injected intravenously with either (A) 3 × 105 or (B) 3 × 106 E. coli per gram of body weight, or (C) 3 × 105 S. aureus per gram of body weight. Survival of the mice was monitored for up to 20 d. Data were analyzed using the Kaplan-Meier plot. The * denotes P < 0.05 for experimental vs. wild-type survival times.
Mentions: As female PKCε−/− mice displayed an unexpected incidence of uterine Gram-negative bacterial infection, and macrophages from PKCε−/− mice were demonstrated to have a severely attenuated response to LPS stimulation, it was hypothesized that PKCε-deficient animals would be more sensitive to Gram-negative bacteria than wild-type controls. To assess this possibility directly, a controlled E. coli bacterial infection was administered intravenously to both PKCε−/− and wild-type mice. At a bacterial dose of 3 × 105 pathogens per gram, ∼40% of the control animals survived for at least 20 d after infection. In contrast, all PKCε−/− mice had died by day 8 (median; 4.6 and 25.3 d for PKCε−/− and wild-type, respectively; Fig. 7 A). At the higher bacterial dose of 3 × 106 pathogens per gram, all animals from the wild-type group had died by day 3. However again, the PKCε−/− mice showed a decreased resistance to infection, as no animal survived beyond the first day (Fig. 7 B). Interestingly, when animals were injected with 3 × 105 Gram-positive S. aureus per gram of body weight, a difference in survival was also observed between PKCε−/− and wild-type animals (median; 6.8 and 21 d, respectively; Fig. 7 C). These results clearly demonstrate that mice deficient for PKCε are more sensitive to both Gram-negative and Gram-positive bacterial infection than wild-type controls, and that this increased sensitivity to infection can significantly decrease the likelihood of bacterial clearance and survival.

Bottom Line: Macrophages from PKCepsilon(-/-) animals demonstrated a severely attenuated response to lipopolysaccharide (LPS) and interferon (IFN)gamma, characterized by a dramatic reduction in the generation of NO, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1beta.This study provides direct evidence that PKCepsilon is critically involved at an early stage of LPS-mediated signaling in activated macrophages.Furthermore, we demonstrate that in the absence of PKCepsilon, host defense against bacterial infection is severely compromised, resulting in an increased incidence of mortality.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Bioquímica (Centro Mixto Consejo Superior de Investigaciones Cientificas-UCM), Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain.

ABSTRACT
To assess directly the role of protein kinase C (PKC)epsilon in the immune system, we generated mice that carried a homozygous disruption of the PKCepsilon locus. PKCepsilon(-/-) animals appeared normal and were generally healthy, although female mice frequently developed a bacterial infection of the uterus. Macrophages from PKCepsilon(-/-) animals demonstrated a severely attenuated response to lipopolysaccharide (LPS) and interferon (IFN)gamma, characterized by a dramatic reduction in the generation of NO, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1beta. Further analysis revealed that LPS-stimulated macrophages from PKCepsilon(-/-) mice were deficient in the induction of nitric oxide synthase (NOS)-2, demonstrating a decrease in the activation of IkappaB kinase, a reduction in IkappaB degradation, and a decrease in nuclear factor (NF)kappaB nuclear translocation. After intravenous administration of Gram-negative or Gram-positive bacteria, PKCepsilon(-/-) mice demonstrated a significantly decreased period of survival. This study provides direct evidence that PKCepsilon is critically involved at an early stage of LPS-mediated signaling in activated macrophages. Furthermore, we demonstrate that in the absence of PKCepsilon, host defense against bacterial infection is severely compromised, resulting in an increased incidence of mortality.

Show MeSH
Related in: MedlinePlus