IL-1β(+) lung-resident macrophages mediate endothelial dysfunction and acute lung injury in sepsis through immune-metabolic crosstalk.

Sepsis-induced acute lung injury (ALI) involves a complex interplay between immune cells and the pulmonary endothelium. However, the molecular regulators that coordinate this interaction remain poorly defined. In a murine sepsis model, we identified a subset of lung-resident macrophages characterized by robust IL-1β expression as pivotal contributors to lung damage. Single-cell RNA sequencing (scRNA-seq) delineated a distinct IL-1β⁺ macrophage population with pronounced pro-inflammatory transcriptional features and enhanced endothelial communication. These macrophages exhibited intensified ligand-receptor interactions with pulmonary endothelial cells, corresponding with elevated vascular leakage and histopathological evidence of injury. Immunoassays, Western blotting, and histopathology confirmed IL-1β upregulation during lung injury. Furthermore, metabolomics and in vitro co-culture experiments demonstrated that IL-1β impairs endothelial integrity and modulates metabolic activity. This study reveals a novel immune-metabolic axis whereby IL-1β(+) macrophages orchestrate endothelial dysfunction and tissue injury in sepsis. Our findings highlight IL-1β as a potential therapeutic target for mitigating ALI in septic patients.