Inhibitory effect of genomic DNA extracted from Pediococcus acidilactici on Porphyromonas gingivalis lipopolysaccharide-induced inflammatory responses

This study aimed to assess whether genomic DNA (gDNA) extracted from Pediococcus acidilactici inhibits Porphyromonas gingivalis lipopolysaccharide (LPS)-induced inflammatory responses in RAW 264.7 cells. Pretreatment with gDNA of P. acidilactici K10 or P. acidilactici HW01 for 15 h effectively inhibited P. gingivalis LPS-induced mRNA expression of interleukin (IL)-1b, IL-6, and monocyte chemoattractant protein (MCP)-1. Although both gDNAs did not dose-dependently inhibit P. gingivalis LPS-induced mRNA expression of IL-6 and MCP-1, they inhibited IL-1b mRNA expression in a dose-dependent manner. Moreover, pretreatment with both gDNAs inhibited the secretion of IL-1b, IL-6, and MCP-1. When RAW 264.7 cells were stimulated with P. gingivalis LPS alone, the phosphorylation of mitogen-activated protein kinases (MAPKs) was increased. However, the phosphorylation of MAPKs was reduced in the presence of gDNAs. Furthermore, both gDNAs restored IkBa degradation induced by P. gingivalis LPS, indicating that both gDNAs suppressed the activation of nuclear factor-kB (NF-kB). In summary, P. acidilactici gDNA could inhibit P. gingivalis LPS-induced inflammatory responses through the suppression of MAPKs and NF-kB, suggesting that P. acidilactici gDNA could be effective in preventing periodontitis.