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- Zhang, Su, et al.
(author)
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STREPTOCOCCAL M1 PROTEIN-INDUCED LUNG INJURY IS INDEPENDENT OF PLATELETS IN MICE.
- 2011
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In: Shock. - 1540-0514. ; Jul 1, s. 86-91
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Journal article (peer-reviewed)abstract
- Streptococcus pyogenes of the M1 serotype is frequently associated with severe streptococcal infections. M1 protein challenge can cause widespread microthrombosis, suggesting a role of platelets in streptococcal sepsis. Herein, we hypothesized that platelets may play a role in M1 protein-induced lung inflammation and injury. M1 protein was injected intravenously in C57Bl/6 mice. For platelet and neutrophil depletion, an anti-GP1balpha antibody and an anti-Gr-1 antibody, respectively, were administered prior to M1 protein challenge. Bronchoalveolar fluid and lung tissue were harvested for analysis of neutrophil infiltration, edema and macrophage inflammatory protein-2 (MIP-2) formation. Blood was collected for analysis of membrane-activated complex-1 (Mac-1) and CD40 ligand (CD40L) expression on neutrophils and platelets as well as soluble CD40L in plasma. M1 protein caused significant pulmonary damage characterized by neutrophil infiltration, increased formation of edema and MIP-2 in the lung as well as enhanced Mac-1 expression on neutrophils. However, M1 protein challenge had no effect on platelet surface expression of CD40L or soluble CD40L levels in plasma. Interestingly, platelet depletion had no influence on M1 protein-induced neutrophil recruitment, MIP-2 production and tissue damage in the lung or Mac-1 expression on neutrophils. Moreover, we observed that M1 protein could bind to neutrophils but not to platelets. On the other hand, neutrophil depletion abolished M1 protein-induced edema formation and tissue damage in the lung. Our data suggest that neutrophils but not platelets are involved in the pathophysiology of M1 protein-provoked pulmonary damage. Thus, neutrophils may constitute a key target in infections caused by Streptococcus pyogenes of the M1 serotype.
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| 2. |
- Zhang, Songen, et al.
(author)
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Simvastatin regulates CXC chemokine formation in streptococcal M1 protein-induced neutrophil infiltration in the lung
- 2011
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In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 300:6, s. 930-939
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Journal article (peer-reviewed)abstract
- Zhang S, Rahman M, Zhang S, Qi Z, Herwald H, Thorlacius H. Simvastatin regulates CXC chemokine formation in streptococcal M1 protein-induced neutrophil infiltration in the lung. Am J Physiol Lung Cell Mol Physiol 300: L930-L939, 2011. First published March 25, 2011; doi:10.1152/ajplung.00422.2010.-Streptococcus pyogenes of the M1 serotype can cause streptococcal toxic shock syndrome and acute lung injury. Statins exert beneficial effects in septic patients although the mechanisms remain elusive. This study examined effects of simvastatin on M1 protein-provoked pulmonary inflammation and tissue injury. Male C57BL/6 mice were pretreated with simvastatin or a CXCR2 antagonist before M1 protein challenge. Bronchoalveolar fluid and lung tissue were harvested for determination of neutrophil infiltration, formation of edema, and CXC chemokines. 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. M1 protein challenge caused massive infiltration of neutrophils, edema formation, and production of CXC chemokines in the lung as well as upregulation of Mac-1 on circulating neutrophils. Simvastatin reduced M1 protein-induced infiltration of neutrophils and edema in the lung. In addition, M1 protein-induced Mac-1 expression on neutrophils was abolished by simvastatin. Furthermore, simvastatin markedly decreased pulmonary formation of CXC chemokines and gene expression of CXC chemokines in alveolar macrophages. Moreover, the CXCR2 antagonist reduced M1 protein-induced neutrophil expression of Mac-1 and accumulation of neutrophils as well as edema formation in the lung. These novel findings indicate that simvastatin is a powerful inhibitor of neutrophil infiltration in acute lung damage triggered by streptococcal M1 protein. The inhibitory effect of simvastatin on M1 protein-induced neutrophil recruitment appears related to reduced pulmonary generation of CXC chemokines. Thus, simvastatin may be a useful tool to ameliorate acute lung injury in streptococcal infections.
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