The alkylation of AIM2 by itaconate mediates macrophage PANoptosis during sepsis

Abstract Although the immunometabolite itaconate has long been considered an anti-inflammatory, we found that its profound accumulation paradoxically drives macrophage cell death and pro-inflammatory responses. However, the exact molecular mechanisms underlying itaconate-induced macrophage toxicity remain unclear. Here, we demonstrate that pathophysiologically relevant high concentrations of itaconate covalently alkylate the absent in melanoma 2 (AIM2) protein at the cysteine 113 (C113) residue. Itaconate-mediated C113 alkylation structurally stabilizes the AIM2 protein and triggers a conformational change, enabling it to drive ASC oligomerization, PANoptosome assembly, and subsequent macrophage PANoptosis. Utilizing in vitro lentiviral reconstitution in primary macrophages alongside plasmid-mediated expression in cell lines, we rigorously confirmed that the AIM2 C113A mutation completely abolishes itaconate-induced AIM2 stabilization and PANoptosis. In vivo models further corroborated the pathogenic contribution of this axis to systemic sepsis. Taken together, our findings reveal a novel pro-inflammatory mechanism of itaconate via the post-translational modification of AIM2. The itaconate-AIM2 alkylation axis provides crucial mechanistic insights into macrophage depletion and systemic inflammation, highlighting a potential therapeutic target for severe sepsis.