A P Ferreira-Duarte1, A S Pinheiro-Torres1, W M Takeshita1, V O Gushiken1, I A Roncalho-Buck1, G F Anhê2, I A DeSouza3. 1. Department of Biology and Physiology, Faculty of Medicine of Jundiai (FMJ), Jundiai (São Paulo), Brazil. 2. Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil. 3. Department of Biology and Physiology, Faculty of Medicine of Jundiai (FMJ), Jundiai (São Paulo), Brazil. Electronic address: ivanidesouza@uol.com.br.
Abstract
BACKGROUND: The lung infections by Staphylococcus aureus are strongly associated with its ability to produce enterotoxins. However, little is known about the mechanisms underlying trafficking of bone marrow (BM) neutrophils during airway inflammation induced by Staphylococcal enterotoxin B (SEB). We therefore aimed to investigate the effects of mouse airways SEB exposure on BM neutrophil counts and its adhesive properties as well as on the release of cytokines/chemokines that orchestrate BM neutrophils trafficking to lung tissue. METHODS: Male BALB/c mice were intranasally exposed to SEB (1 µg), and at 4, 16 and 24 h thereafter, BM, circulating blood, bronchoalveolar lavage (BAL) fluid and lung tissue were collected. BM neutrophils adhesion, MAC-1 and LFA1-α expressions (by flow cytometry) as well as measurement of cytokine and/or chemokines levels were assayed after SEB-airway exposure. RESULTS: Prior exposure to SEB promoted a marked influx of neutrophils to BAL and lung tissue, which was accompanied by increased counts of BM immature neutrophils and blood neutrophilia. BM neutrophil expressions of LFA1-α and MAC-1 were unchanged by SEB exposure whereas a significant enhancement of adhesion properties to VCAM-1 was observed. The early phase of airway SEB exposure was accompanied by high levels of GM-CSF, G-CSF, IFN-γ, TNF-α and KC/CXCL1, while the latter phase by the equilibrated actions of SDF1-α and MIP-2. CONCLUSION: Mouse airways exposure to SEB induces BM cytokines/chemokines release and their integrated actions enhance the adhesion of BM neutrophils leading to acute lung injury.
BACKGROUND: The lung infections by Staphylococcus aureus are strongly associated with its ability to produce enterotoxins. However, little is known about the mechanisms underlying trafficking of bone marrow (BM) neutrophils during airway inflammation induced by Staphylococcal enterotoxin B (SEB). We therefore aimed to investigate the effects of mouse airways SEB exposure on BM neutrophil counts and its adhesive properties as well as on the release of cytokines/chemokines that orchestrate BM neutrophils trafficking to lung tissue. METHODS: Male BALB/c mice were intranasally exposed to SEB (1 µg), and at 4, 16 and 24 h thereafter, BM, circulating blood, bronchoalveolar lavage (BAL) fluid and lung tissue were collected. BM neutrophils adhesion, MAC-1 and LFA1-α expressions (by flow cytometry) as well as measurement of cytokine and/or chemokines levels were assayed after SEB-airway exposure. RESULTS: Prior exposure to SEB promoted a marked influx of neutrophils to BAL and lung tissue, which was accompanied by increased counts of BM immature neutrophils and blood neutrophilia. BM neutrophil expressions of LFA1-α and MAC-1 were unchanged by SEB exposure whereas a significant enhancement of adhesion properties to VCAM-1 was observed. The early phase of airway SEB exposure was accompanied by high levels of GM-CSF, G-CSF, IFN-γ, TNF-α and KC/CXCL1, while the latter phase by the equilibrated actions of SDF1-α and MIP-2. CONCLUSION:Mouse airways exposure to SEB induces BM cytokines/chemokines release and their integrated actions enhance the adhesion of BM neutrophils leading to acute lung injury.