Extracellular adenosine triphosphate (ATP), a key danger-associated molecular pattern (DAMP) molecule, is released to the extracellular medium during inflammation by injured parenchymal cells, dying leukocytes, and activated platelets. ATP directly activates the plasma membrane channel P2X7 receptor (P2X7R), leading to an intracellular influx of K+, a key trigger inducing NLRP3 inflammasome activation. However, the mechanism underlying P2X7R-mediated activation of NLRP3 inflammasome is poorly understood, and additional molecular mediators have not been identified. Here, we demonstrate that Paxillin is the molecule connecting the P2X7 receptor and NLRP3 inflammasome through protein interactions. We show a distinct mechanism by which Paxillin promotes ATP-induced activation of the P2X7 receptor and NLRP3 inflammasome. Extracellular ATP induces Paxillin phosphorylation and then facilitates Paxillin-NLRP3 interaction. Interestingly, Paxillin enhances NLRP3 deubiquitination and activates NLRP3 inflammasome upon ATP treatment and K+ efflux. Moreover, we demonstrated that USP13 is a key enzyme for Paxillin-mediated NLRP3 deubiquitination upon ATP treatment. Notably, extracellular ATP promotes Paxillin and NLRP3 migration from the cytosol to the plasma membrane and facilitates P2X7R-Paxillin interaction and PaxillinNLRP3 association, resulting in the formation of the P2X7R-Paxillin-NLRP3 complex. Functionally, Paxillin is essential for ATP-induced NLRP3 inflammasome activation in mouse BMDMs and BMDCs as well as in human PBMCs and THP-1-differentiated macrophages. We have identified paxillin as a mediator of NLRP3 inflammasome activation. Paxillin plays key roles in ATP-induced activation of the P2X7 receptor and NLRP3 inflammasome by facilitating the formation of the P2X7R-Paxillin-NLRP3 complex.

中文翻译：

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Paxillin介导ATP诱导的P2X7受体和NLRP3炎性小体活化

细胞外三磷酸腺苷（ATP）是一种关键的危险相关分子模式（DAMP）分子，在炎症过程中被受损的实质细胞，垂死的白细胞和活化的血小板释放到细胞外介质中。ATP直接激活质膜通道P2X7受体（P2X7R），导致细胞内K +大量涌入，这是诱导NLRP3炎性体激活的关键触发因素。但是，对P2X7R介导的NLRP3炎性小体激活的机制了解甚少，尚未发现其他分子介体。在这里，我们证明Paxillin是通过蛋白质相互作用连接P2X7受体和NLRP3炎性小体的分子。我们显示了一种独特的机制，其中Paxillin促进ATP诱导的P2X7受体和NLRP3炎性小体的激活。细胞外ATP诱导Paxillin磷酸化，然后促进Paxillin-NLRP3相互作用。有趣的是，在进行ATP处理和K +外排后，Paxillin增强NLRP3去泛素化并激活NLRP3炎性小体。此外，我们证明了USP13是ATP处理后Paxillin介导的NLRP3去泛素化的关键酶。值得注意的是，细胞外ATP促进Paxillin和NLRP3从细胞质迁移到质膜并促进P2X7R-Paxillin相互作用和PaxillinNLRP3缔合，从而导致P2X7R-Paxillin-NLRP3复合物的形成。在功能上，Paxillin对小鼠BMDM和BMDC以及人PBMC和THP-1分化的巨噬细胞中ATP诱导的NLRP3炎性小体激活至关重要。我们已将帕西林鉴定为NLRP3炎性体激活的介体。