| 1. |
- Zhang, Songen, et al.
(author)
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Streptococcal M1 protein triggers farnesyltransferase-dependent formation of CXC chemokines in alveolar macrophages and neutrophil infiltration in the lung.
- 2012
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In: Infection and Immunity. - 1098-5522. ; 80:11, s. 3952-3959
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Journal article (peer-reviewed)abstract
- M1 serotype of Streptococcus pyogenes plays an important role in streptococcal toxic shock syndrome. Simvastatin, a HMG-CoA reductase inhibitor, has been shown to inhibit streptococcal M1 protein-induced acute lung damage although downstream mechanisms remain elusive. Protein isoprenylation, such as farnesylation and geranylgeranylation, has been suggested to regulate anti-inflammatory effects exerted by statins. Herein, we examined the effect of a farnesyltransferase inhibitor (FTI-277) on M1 protein-triggered lung inflammation. Male C57BL/6 mice were treated with FTI-277 prior to M1 protein challenge. Bronchoalveolar fluid and lung tissue were harvested for quantification of neutrophil recruitment, edema and CXC chemokine formation. Flow cytometry was used to determine Mac-1 expression on neutrophils. Gene expression of CXC chemokines was determined in alveolar macrophages by using quantitative RT-PCR. We found that administration of FTI-277 markedly decreased M1 protein-induced accumulation of neutrophils, edema formation and tissue damage in the lung. Notably, inhibition of farnesyltransferase abolished M1 protein-evoked production of CXC chemokines in the lung and gene expression of CXC chemokines in alveolar macrophages. Moreover, FTI-277 completely inhibited chemokine-induced neutrophil migration in vitro. However, farnesyltransferase inhibition had no effect on M1 protein-induced expression of Mac-1 on neutrophils. Our findings suggest that farnesyltransferase is a potent regulator of CXC chemokine formation in alveolar macrophages and that inhibition of farnesyltransferase not only reduces neutrophil recruitment but also attenuates acute lung injury provoked by streptococcal M1 protein. We conclude that farnesyltransferase activity is a potential target in order to attenuate acute lung damage in streptococcal infections.
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| 2. |
- Zhang, Songen, et al.
(author)
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p38 Mitogen-activated protein kinase signaling regulates streptococcal M1 protein-induced neutrophil activation and lung injury.
- 2012
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In: Journal of Leukocyte Biology. - : Oxford University Press (OUP). - 1938-3673 .- 0741-5400. ; 91, s. 137-145
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Journal article (peer-reviewed)abstract
- M1 serotype of Streptococcus pyogenes can cause STSS and acute lung damage. Herein, the purpose was to define the role of p38 MAPK signaling in M1 protein-induced pulmonary injury. Male C57BL/6 mice were treated with specific p38 MAPK inhibitors (SB 239063 and SKF 86002) prior to M1 protein challenge. Edema, neutrophil infiltration, and CXC chemokines were determined in the lung, 4 h after M1 protein administration. Flow cytometry was used to determine Mac-1 expression. Phosphorylation and activity of p38 MAPK were determined by immunoprecipitation and Western blot. IVM was used to analyze leukocyte-endothelium interactions in the pulmonary microcirculation. M1 protein challenge increased phosphorylation and activity of p38 MAPK in the lung, which was inhibited by SB 239063 and SKF 86002. Inhibition of p38 MAPK activity decreased M1 protein-induced infiltration of neutrophils, edema, and CXC chemokine formation in the lung, as well as Mac-1 up-regulation on neutrophils. IVM showed that p38 MAPK inhibition reduced leukocyte rolling and adhesion in the pulmonary microvasculature of M1 protein-treated mice. Our results indicate that p38 MAPK signaling regulates neutrophil infiltration in acute lung injury induced by streptococcal M1 protein. Moreover, p38 MAPK activity controls CXC chemokine formation in the lung, as well as neutrophil expression of Mac-1 and recruitment in the pulmonary microvasculature. In conclusion, these findings suggest that targeting the p38 MAPK signaling pathway may open new opportunities to protect against lung injury in streptococcal infections.
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| 3. |
- Zhang, Songen, et al.
(author)
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Streptococcal M1 Protein-Provoked CXC Chemokine Formation, Neutrophil Recruitment and Lung Damage Are Regulated by Rho-Kinase Signaling.
- 2012
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In: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 4:4, s. 399-408
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Journal article (peer-reviewed)abstract
- Streptococcal toxic shock syndrome is frequently caused by Streptococcus pyogenes of the M1 serotype. The aim of this study was to determine the role of Ras-homologous (Rho)-kinase signaling in M1 protein-provoked lung damage. Male C57BL/6 mice received the Rho-kinase-specific inhibitor Y-27632 before administration of M1 protein. Edema, neutrophil accumulation and CXC chemokines were quantified in the lung 4 h after M1 protein challenge. Flow cytometry was used to determine Mac-1 expression. Quantitative RT-PCR was used to determine gene expression of CXC chemokine mRNA in alveolar macrophages. M1 protein increased neutrophil accumulation, edema and CXC chemokine formation in the lung as well as enhanced Mac-1 expression on neutrophils. Inhibition of Rho-kinase signaling significantly reduced M1 protein-provoked neutrophil accumulation and edema formation in the lung. M1 protein-triggered pulmonary production of CXC chemokine and gene expression of CXC chemokines in alveolar macrophages was decreased by Y-27632. Moreover, Rho-kinase inhibition attenuated M1 protein-induced Mac-1 expression on neutrophils. We conclude that Rho-kinase-dependent neutrophil infiltration controls pulmonary tissue damage in response to streptococcal M1 protein and that Rho-kinase signaling regulates M1 protein-induced lung recruitment of neutrophils via the formation of CXC chemokines and Mac-1 expression.
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