Virulence of Filifactor alocis lipoteichoic acid on human gingival fibroblast.

Objectives: The purpose of this study was to investigate virulence of lipoteichoic acid extracted from Filifactor alocis (F. alocis) through comparison of previously known bacterial virulence factors.

Design: F. alocis was cultured in columbia media including L-arginine and L-cysteine, and lipoteichoic acid (LTA) from F. alocis was purified using organic solvent and bead extraction. Human gingival fibroblasts (HGFs) were treated with the extracted LTA and other Gram-positive LTA or lipopolysaccharide of other periodontopathogens. The induction of cytokine expression was examined by real-time RT-PCR and ELISA, and the stimulated signaling pathway by the LTA was investigated by immunoblotting and various inhibitors.

Results: LTA induced expression of pro-inflammatory cytokines and Matrix-metalloprotein 2. Also, F. alocis LTA induced expression pro-inflammatory cytokines similar to Porphyromonas gingivalis lipopolysaccharide. The LTA activated NF-κB and MAP kinase pathway. Furthermore, the induction of TNF-α, IL-6, IL-8, and MMP-2 expression by F. alocis LTA was reduced by the inhibitor of NF-κB, ERK, JNK, and p38 pathway.

Conclusions: LTA of F. alocis, a bacterium recently detected in periodontal patients, may play an important role in inducing periodontitis by induction of expression of pro-inflammatory cytokines.