Intracellular NOD2 Activation Promotes Maturation and Antigen-Presenting Functions of Dentritic Cells Exposed to Porphyromonas Gingivalis Lipopolysaccharide

Our study proved that intracellular NOD2 in DCs could be activated by MDP, which could promote maturation and the ability to prime Th0 cells to Th2 cells of DCs exposed to P. gingivalis-LPS. Background: To study the roles of muramyl dipeptide (MDP) in dendritic cells (DCs) exposed to Porphyromonas gingivalis lipopolysaccharide (P. gingivalis-LPS) on maturation and antigen-presenting functions of DCs. To explore the possible mechanism of DCs in periodontitis. Methods: Flow cytometry was used to detect CD11c, MHC-II, CD80, CD86, and CD40 expression, and ELISA was used to detect IL-12, IFN-gamma, IL-10, and IL-13 secreted by DCs. RT-PCR analysis was used to detect NOD2, TLR2, and TLR4 mRNA expression in DCs. CCK8 was used to assay CD4(+)T cell proliferation. Results: MDP had a weak ability to stimulate DC maturation but MDP could promote DC maturation stimulated by P. gingivalis-LPS. MDP could facilitate TLR2 mRNA expression in DCs exposed to P. gingivalis-LPS. The ability of MDP to promote DCs secreting cytokines was far below P. gingivalis-LPS but MDP could promote the functions of Th2 cell-promoting DCs induced by P. gingivalis-LPS. MDP could promote CD4(+)T cell proliferation primed by DCs exposed to P. gingivalis-LPS and elevate the ability of DCs exposed to P. gingivalis-LPS to prime Th0 cells to Th2 cells. Conclusions: Intracellular NOD2 in DCs could be activated by MDP, which could promote maturation and the ability to prime Th0 cells to Th2 cells of DCs exposed to P. gingivalis-LPS.