Single-Cell RNA Sequencing Combined with MEBOCOST Reveals Alveolar Macrophage-Mediated Immunometabolic Communication Mechanisms in Sepsis-Induced Acute Lung Injury

Background: Sepsis-induced acute lung injury (SI-ALI) leads to high mortality in critically ill patients, and no specific targeted treatments are available. Current studies mainly characterize intercellular crosstalk via protein–ligand–receptor frameworks, while metabolite-derived immune signal transmission is largely unclarified. Alveolar macrophages are located at the alveolar barrier and may act as central metabolic coordinators to trigger neutrophil-mediated lung inflammation, yet the complete metabolite signaling network has not been systematically mapped. Methods: We integrated single-cell and bulk transcriptomic datasets from CLP-induced septic mouse lungs. CellChat and MEBOCOST were jointly used to reconstruct protein–metabolite dual communication networks. LASSO regression and random forest were combined to screen core metabolic hub genes, followed by single-cell expression mapping and in vivo histology & qPCR validation. Results: We identified a pivotal alveolar macrophage–neutrophil immunometabolic axis dominated by iron-Slc40a1 and LTB4-Ltb4r1 signaling. Three hub genes (Pmvk, Slc2a1, Slc7a11) coordinately regulate inflammatory pathways, among which myeloid-enriched Slc7a11 balances cellular redox and paracrine inflammatory responses. Conclusions: This study establishes the first dual-layer cell communication atlas for SI-ALI, proposes a macrophage-centered metabolic inflammatory regulatory model, and highlights Slc7a11 as a potential therapeutic target for septic lung injury.