PRKCB Mediates Ferroptosis-Immune Crosstalk in Acute Lung Injury: Insights from Integrated Single-Cell Transcriptomics.

BACKGROUND: Acute respiratory distress syndrome (ARDS), previously classified under the broader category of acute lung injury (ALI), a life-threatening condition characterized by uncontrolled inflammation, remains a major challenge in critical care medicine. Ferroptosis, an iron-dependent cell death driven by lipid peroxidation, is implicated in ALI pathogenesis, yet its cell-specific landscape and interplay with the immune microenvironment remain poorly defined. METHODS: We integrated single-cell and bulk transcriptomic data from public databases (12 samples, 50,316 high-quality cells). Cell populations were annotated, and ferroptosis propensity was scored using the FerrDb gene set. Cell-cell communication, transcriptional regulation, and pseudotime trajectory analyses were performed. Key predictions were validated in an LPS-induced alveolar epithelial cell (MLE-12) model using the PRKCB inhibitor Enzastaurin and the ferroptosis inhibitor Ferrostatin-1. RESULTS: We constructed a cellular atlas of ALI, noting a significant shift toward immune cell infiltration (macrophages/neutrophils >80%). Ferroptosis driver scores were significantly elevated in ALI, particularly within epithelial and myeloid cells, but not fibroblasts. CellChat analysis revealed a remodeled communication network centered on myeloid cells, with enhanced interactions involving ferroptosis-high-risk cells. Pseudotime analysis of epithelial cells illustrated a continuous transition toward a ferroptotic state, accompanied by stage-specific gene expression. Multi-algorithm integration identified Protein Kinase C Beta (PRKCB) as a core regulatory gene. In vitro validation confirmed that PRKCB inhibition attenuated LPS-induced cell death, lipid peroxidation, and dysregulation of key ferroptosis markers (GPX4, SLC7A11, ACSL4). CONCLUSION: Our study provides the first single-cell resolution map of ferroptosis heterogeneity in ALI, uncovering a PRKCB-mediated positive feedback loop between ferroptosis and immune dysregulation. These findings identify PRKCB as a potential therapeutic target to disrupt this pathogenic crosstalk.