ZBP1-driven pyroptosis-associated alveolar macrophages exacerbate epithelial dysfunction in sepsis.

The lung is highly vulnerable to inflammatory injury during sepsis, and acute lung injury (ALI) is a major cause of mortality in critically ill patients. Pyroptosis amplifies immune responses by promoting the release of inflammatory cytokines, and Z-DNA binding protein 1 (ZBP1) has emerged as a key upstream regulator of programmed cell death and inflammatory signaling. Nevertheless, the contribution of ZBP1 to human sepsis-induced ALI and its associated cellular programs remains poorly defined. Here, by integrating single-cell RNA sequencing data from bronchoalveolar lavage fluid (BALF) of patients with sepsis-induced ALI and from septic mouse lungs, we identified a distinct subset of pyroptosis-associated macrophages that expands during disease progression and exhibits ZBP1-dependent inflammasome activation. ZBP1 activation promoted inflammasome assembly, induced macrophage pyroptosis, and released pro-inflammatory mediators that impaired mitochondrial function and barrier integrity of alveolar type II (AT2) epithelial cells. ZBP1 deficiency markedly attenuated macrophage-AT2 inflammatory signaling and reduced the inflammatory amplification loop. Collectively, these findings identify ZBP1-mediated macrophage pyroptosis as a critical mechanism driving epithelial dysfunction during sepsis-induced ALI and provide a rationale for developing ZBP1-targeted strategies to restore immune-epithelial homeostasis and prevent organ failure in sepsis. In sepsis-induced acute lung injury, ZBP1 drives macrophage pyroptosis and amplifies inflammatory signaling, thereby promoting mitochondrial dysfunction, inflammatory activation, and barrier integrity loss in AT2 epithelial cells. Zbp1 deficiency suppresses macrophage pyroptosis, weakens macrophage-epithelial inflammatory crosstalk, and mitigates epithelial injury.