Anti-inflammatory Effects of PMX205 in Mouse Macrophage Periodontitis Model

C5a receptor antagonist PMX205 is a synthetic hexapeptide capable of blocking C5a-C5a receptor (C5aR) axis by simulating C5a active C-terminal amino acid residues. This hexapeptide presents good anti-inflammatory effects in a series of inflammation models. The anti-inflammatory effect of PMX205 on periodontitis is yet to be fully fathomed.

To examine the anti-inflammatory effects of PMX205 on RAW264.7 mouse macrophages exposed to gingipain extracts and Porphyromonas gingivalis (P. gingivalis).

MTT assay was carried out so as to specify the cytotoxicity of PMX205. RAW264.7 cells were co-cultured in vitro with gingipain extracts or P. gingivalis to simulate the periodontitis inflammatory milieu. Real-time quantitative PCR, ELISA and Griess assay were performed in order to detect tumor necrosis factor-α (TNF-α), IL-6, IL-23, nitric oxide (NO), IL-10, transforming growth factor-β1 (TGF-β1), andarginase-1 (Arg-1). Furthermore, phagocytosis assay was done to evaluate the phagocytic capacity of RAW 264.7 cells. Finally, western blot analysis was conducted to evaluate myeloid differentiation factor 88 (MyD88).

PMX205 increased the expression levels of bacteriostatic substances (NO and IL-23) and anti-inflammatory cytokines (TGF-β1, IL-10 and Arg-1); however, it reduced the expression levels of proinflammatory cytokines TNF-α and IL-6 once RAW 264.7 macrophages were stimulated via gingipain extracts or P. gingivalis. In addition, PMX205 promoted the macrophage phagocytosis and down-regulated protein expression of MyD88.

PMX205 has recognizable anti-inflammatory effects in RAW 264.7 cell inflammation model, a finding which probably opens doors to future investigations on new targets for the prevention and treatment of chronic periodontitis.