METTL3-mediated m6A on nascent RNA coordinates translational and transcriptional programs to activate the NLRP3 inflammasome in macrophages

NLRP3 inflammasome activation requires both transcriptional priming and complex assembly, but how RNA m⁶A methylation coordinates these steps remains unclear. Here, we show that m⁶A levels increase during macrophage NLRP3 inflammasome activation and that METTL3 loss suppresses this activation. Myeloid-specific Mettl3 knockout mice display reduced inflammation and improved metabolic outcomes in lipopolysaccharide (LPS)-induced sepsis, monosodium urate (MSU)-induced arthritis, and diet-induced obesity. Integrated chromatin-associated RNA sequencing (chrRNA-seq), kethoxal-assisted single-stranded DNA sequencing (KAS-seq), and chrRNA-methylated RNA immunoprecipitation (MeRIP)-seq analyses show that METTL3 installs m⁶A co-transcriptionally on nascent Jak1, Nlrp3, and Il1β RNAs and that METTL3 regulates dynamic transcription and chromatin accessibility while selectively maintaining Nlrp3/Il1β transcription. YTHDF1-driven translation of Jak1 activates the JAK1-STAT3-C/EBPβ axis to initiate Nlrp3/Il1β transcription, and m⁶A-YTHDF1 translation of Nlrp3/Il1β amplifies protein output, forming a coupled transcriptional-translational circuit. Pharmacologic STAT3 inhibition and METTL3 catalytic rescue validate this pathway and identify METTL3-mediated m⁶A as a therapeutic target for inflammasome-driven diseases.