The interaction between serum amyloid A and Toll‐like receptor 2 pathway regulates inflammatory cytokine secretion in human gingival fibroblasts

BACKGROUND Serum amyloid A (SAA) has been identified to trigger inflammation response, and play a crucial role in chronic inflammatory diseases. However, the regulatory mechanism of SAA still remains unclear during the development of periodontitis METHODS: SAA mRNA and protein expression were detected in healthy and inflammatory gingival tissues using real-time polymerase chain reaction (PCR) and immunohistochemistry. Human recombinant SAA (Apo-SAA), Pam3CSK4 (a Toll-like receptor (TLR) 2 ligand), siRNA-SAA, or TLR2 neutralizing antibody was applied to treat human gingival fibroblasts, respectively, or combined. SAA, TLRs, and inflammatory cytokines interleukin (IL)-6 and IL-8 were analyzed by real-time PCR, western blotting, or enzyme-linked immunosorbent assay. RESULTS SAA expression increased in human inflammatory gingival tissues from patients with periodontitis (P