Uric Acid Activates NLRP3 Inflammasome In Macrophages Based On P2X7R-independent Pathway In Gout

Scope:Gout is a crystal-associated joint disease caused by deposition of monosodium uric acid(monosodium urate,MSU)crystals.Since,regulating immune response and P2X7R-NLRP3 inflammasome activation with small molecule inhibitors might be a potential therapeutic strategy to treat and prevent gout.In this study,we investigated the potential therapeutic mechanisms of gout by macrophages.Methods:In vitro model was created by treating murine peritoneal macrophages(MPM)and murine bone marrow-derived macrophages(BMDMs)with LPS/ATP and subsequently stimulated with MSU crystals.The expression of intracellular and extracellular inflammation related cytokines was detected by Western blot and ELISA.Results:In vitro,treated with lipopolysaccharide(LPS)plus MSU crystals,both of mouse peritoneal macrophages and mouse bone marrow-derived macrophages(BMDMs)released pro-IL-1? and mature IL-1?,which was blocked by TLR4 inhibitor,CLI-095 and NF-?B inhibitor,PDTA.However,A438079,a selective P2X7R inhibitor,failed to block the cleavage and release of IL-1?.Additionally,the release of pro-IL-1? and mature IL-1? was decreased by caspase-1 inhibitor and caspase-3 inhibitor in mouse peritoneal macrophages and BMDMs,but interleukin 1 receptor antagonist(IL-1Ra),interleukin 36 receptor antagonist(IL-36Ra)were not decreased pro-IL-1? and mature IL-1?.Besides,AICAR,an AMPK stimulator,decreased secreted IL-1? level in mouse peritoneal macrophages,and colchicine not decreased secreted IL-1? level in mouse peritoneal macrophages.Conclusion:MSU crystals regulate inflammasome-mediated cleavage and release of pro-IL-1? and mature IL-1? through TLR4-NF-?B pathway,but independent of P2X7R activation in macrophages,suggested that P2X7R needs to be carefully considered as a gout target.