Interleukin-1 Promotes MDP-induced Cytokine Production Via Up-regulation Of NOD2 And RIP2 In Monocytic THP-1 Cells

Objectives: NOD like receptor activated MAPK and NF-κB signaling pathway can induce inflammatory responses,and then participate in the development of cardiovascular disease.In this study,we analyzed the expression of the inflammatory cytokines and the signal pathway in THP1 cells pretreated with IL-1β,and re-stimulated with MDP,elucidated the molecular mechanism of the effect of IL-1β on NOD2-induced inflammatory responses in THP1 cells,and finally to provide evidences for clinical intervention of cardiovascular disease.Methods: THP1 cells were cultured with RPMI-1640.THP1 cells were treated with differential concentrations of IL-1β and MDP.The mRNA levels of cytokines,NOD2,and RIP2 were detected by real-time RT-PCR method.The protein levels of RIP2 were measured by western blot.ELISA was used to examine the protein levels of chemokines(IL-8,GRO-α,GRO-β)and pro-inflammatory cytokines(TNF-α,IL-1β).Signal transduction inhibitor concentration was 10 μM.Western blot was used to detect the phosphorylation level of signal molecules.FACS was used to detect the protein levels of NOD2.Results: 1.Compared with the MDP-treated alone groups,IL-1β significantly up-regulated the expression of cytokines in a dose-dependent manner.2.MDP induced the phosphorylated protein levels of ERK,JNK、P38 and P65 in a dose-and time-dependent manner.3.Compared with the MDP-treated alone groups,IL-1βsignificantly up-regulated the phosphorylated protein levels of ERK,JNK、P38 and P65 induced by MDP in a dose-dependent manner.4.IL-1β significantly up-regulated the expression of NOD2 and RIP2 at both mRNA and protein levels in a time-dependent manner.5.IL-1β significantly up-regulated the expression of A20 at both mRNA and protein levels in a time-dependent manner.6.ERK inhibitor,U0126 down-regulated MDP-induced TNF-α 、 IL-1β 、 IL-8 、 GRO-αsignificantly.JNK inhibitor SP600125down-regulated the expression of IL-8.P38 inhibitor SB203580down-regulated the expression of GRO-α.NF-κB inhibitor Bay117082 did not dwon-regulated every cytokine.7.IL-1β treatment induced the up-regulation of A20.8.A20 over-expression by gene transfer did not down-regulate NOD2-induced cytokines.Conclusion: 1.IL-1β sensitizes NOD2 to produce pro-inflammatory cytokines in monocytic THP1 via up-regulation of NOD2 and RIP2,related to ERK,JNK and P38 signaling pathway.2.IL-1β treatment induced the up-regulation of A20,but A20 did not down-regulate MDP-induced cytokines.