[Mechanisms of up-reguation of chemokine CXCL8 in human neutrophils induced by Streptococcus pneumoniae surface protein A].

OBJECTIVE: To study the mechanisms by which pneumococcal surface protein A (PspA) up-regulates chemokine CXCL8 in human neutrophils. METHODS: Human neutrophils were treated by the inhibitors of NF-κB, p38MARK, ERK, JNK respectively, and then CXCL8 concentration in the cell-free supernatants after stimulation with PspA was measured by ELISA. The total cellular proteins and nuclear extracts of neutrophils after stimulation with PspA were prepared to detect p38MARK and NF-κB contents by ELISA. The total cellular proteins were also used for the determination of the phosphorylation levels of p38MAPK and IkB-α by Western blotting. RESULTS: NF-κB or p38MARK inhibitor instead of ERK or JNK inhibitor significantly suppressed the release of CXCL8 induced by PspA. In addition, PspA also increased the activity of p38MAPK and the concentration of NF-κB in the neutrophils. Western blotting indicated that PspA enhanced the phosphorylation levels of p38MAPK and IkB-α. CONCLUSION: The secretion of CXCL8 in human neutrophils induced by PspA is regulated by p38MAPK and NF-κB pathways.