NLRP3 Cys126 palmitoylation by ZDHHC7 Promotes Inflammasome Activation

Abstract NACHT-, leucine-rich-repeat- (LRR), and pyrin domain-containing protein 3 (NLRP3) mediates inflammasome activation in response to multiple pathogen and damage-associated molecular patterns in macrophages. Hyperactivation of NLRP3 inflammasome contributes to many human chronic inflammatory diseases. Understanding how NLRP3 inflammasome is regulated can potentially provide new strategies to treat inflammatory diseases. Here, we demonstrated that NLRP3 is palmitoylated on Cys126 by palmitoyl-acyltransferase ZDHHC7 in macrophages, which is critical for NLRP3-mediated inflammasome activation. Perturbating NLRP3 Cys126 palmitoylation by ZDHHC7 knockout, pharmacological inhibition, or modification site mutation, diminishes NLRP3 activation and the consequential Caspase-1 and Gasdermin D (GSDMD) cleavage, and IL-1β and IL-18 secretion in mouse primary macrophages and human macrophages. Furthermore, NLRP3 Cys126 palmitoylation is vital for inflammasome activation in vivo , as Zdhhc7 knockout, pharmacological inhibition, or NLRP3 C126A mutation protects mice from LPS-induced endotoxic shock and monosodium urate (MSU)-induced peritonitis. Mechanistically, ZDHHC7-mediated NLRP3 Cys126 palmitoylation promotes resting NLRP3 localizing on the trans -Golgi network (TGN) and activated NLRP3 on the dispersed TGN (dTGN), which is indispensable for the recruitment and oligomerization of adaptor protein ASC after inflammasome activation. The activation of NLRP3 by ZDHHC7-mediated Cys126 palmitoylation is different from the previously reported inhibitory effect by ZDHHC12-mediated Cys841 palmitoylation, highlighting the versatile regulatory roles of S -palmitoylation. Therefore, our study identifies a new regulatory mechanism of NLRP3 activation and suggests targeting ZDHHC7 or NLRP3 Cys126 residue as a potential therapeutic strategy to treat NLRP3-related human disorders. Highlights NLRP3 Cys126 is palmitoylated by ZDHHC7. ZDHHC7 promotes NLRP3 activation in macrophages, which can be inhibited by ZDHHCs inhibitors, 2-bromopalmitate and MY-D4. Cys126 palmitoylation of NLRP3 is critical for NLRP3 activation. NLRP3 TGN/dTGN localization depends on ZDHHC7-mediated Cys126 palmitoylation, which is crucial for ASC recruitment and inflammasome assembly. NLRP3 inflammasome activation by ZDHHC7 differs from ZDHHC12-mediated NLRP3 inhibition.