Methylglyoxal-modification of NLRP3 interrupts NLRP3-NEK7 interaction diminishing inflammasome activation and neuroinflammation.

BACKGROUND: The NLRP3 inflammasome is a supramolecular complex that mediates pyroptosis and the production of inflammatory cytokines. Aberrant activation of the NLRP3 inflammasome has been implicated in the pathogenesis of various diseases, including cancers, neurodegenerative disorders, metabolic diseases, and autoimmune conditions. Methylglyoxal (MGO), a highly reactive carbonyl compound derived from glycolysis, exerts unclear effects on NLRP3 inflammasome activation. This study aimed to clarify the impact of MGO on NLRP3 inflammasome activity and its underlying mechanism. METHODS: NLRP3 inflammasome activation was assessed in vitro in macrophages primed with LPS and stimulated with NLRP3 activators (e.g., nigericin, ATP, or imiquimod), and in vivo using LPS-induced peritonitis and experimental autoimmune encephalomyelitis (EAE) mouse models. Techniques including immunoblotting, immunofluorescent staining, flow cytometry, ELISA, and immunoprecipitation were employed to investigate the effects of MGO on NLRP3 inflammasome activation and its mechanism of action. RESULTS: MGO significantly suppressed NLRP3 inflammasome activation in macrophages, reducing pyroptosis and mature IL-1β release. It ameliorated inflammatory cell infiltration in the mouse models of LPS-induced peritonitis and EAE. Mechanistically, MGO did not interfere with the potassium efflux or α-tubulin acetylation triggered by NLRP3 inflammasome activators, but rather MGO covalently bonded to NLRP3, interrupted the interaction between NLRP3 and NEK7, which interfered with the assembly of NLRP3 inflammasome and subsequently suppressed pyroptosis and production of mature, bioactive inflammatory cytokines. CONCLUSIONS: MGO suppresses NLRP3 inflammasome activation and associated inflammation by covalently binding NLRP3 and disrupting its interaction with NEK7. This reveals a novel mechanism for MGO in innate immunity and identifies NLRP3 as a direct MGO target, suggesting potential therapeutic strategies for NLRP3-driven inflammatory diseases.