Abstract
Nod-like receptor protein 3 (NLRP3)-mediated pyroptosis has a causal role in the pathogenesis of gout. P2Y14 receptor (P2Y14R) distributed in immune cells including macrophages is a Gi-coupled receptor that inhibits the synthesis of cAMP, which has been regarded as a potential regulator of inflammatory response. Nevertheless, the role of P2Y14R in MSU-induced pyroptosis of macrophages involved in acute gouty arthritis is still unclear. In our present study, P2Y14R knockout (P2Y14R-KO) disrupted MSU-induced histopathologic changes in rat synoviums, accompanied with a significant inhibition of pyroptotic cell death characterized by Caspase-1/PI double-positive and blockade of NLRP3 inflammasome activation in synovial tissues, which was consistent with that observed in in vitro studies. Owing to the interaction of NLRP3 inflammasome and cAMP, we then investigated the effect of adenylate cyclase activator (Forskolin) on macrophage pyroptosis and gout flare caused by MSU stimulation. The reversal effect of Forskolin verified the negative regulatory role of cAMP in MSU-induced pyroptosis. More importantly, adenylate cyclase inhibitor (SQ22536) intervention led to a reversal of protection attributed to P2Y14R deficiency. Findings in air pouch animal models also verified aforementioned experimental results. Our study first identified the role of P2Y14R/cAMP/NLRP3 signaling pathway in acute gouty arthritis, which provides a novel insight into the pathological mechanisms of pyroptosis-related diseases.