Activation of transcription factors and IL-8 expression in neutrophils stimulated with lipopolysaccharide from Porphyromonas gingivalis.

DNA binding activity of NF-kappa B and AP-1 were examined in neutrophils stimulated with LPS purified from P. gingivalis, a major pathogenic bacteria of periodontitis lesion. Porphyromonas gingivalis LPS enhanced the activity reaching a peak at a concentration of 500 ng/ml in the absence of serum. The NF-kappa B activation stimulated with 10 ng/ml of P. gingivalis LPS was suppressed approximately 44% by treatment of neutrophils with anti-CD14 antibody under the presence of serum. Increase in the steady-state IL-8 mRNA level was concomitantly observed by stimulation of neutrophils with 500 ng/ml of P. gingivalis LPS under the absence of serum. These results indicate that P. gingivalis LPS activates NF-kappa B and AP-1 in both serum-dependent and -independent manners, followed by increased IL-8 transcription in neutrophils, and suggested a role for P. gingivalis LPS in IL-8 synthesis by neutrophils in inflamed gingiva and GCF.