The PIK3C3/MAPK14 axis drives M1 polarization via autophagy Inhibition to exacerbate Sepsis-Induced acute lung injury.

Dysregulation of macrophage autophagy plays a critical role in sepsis-induced acute lung injury (ALI); however, its underlying mechanism remains unclear. In this study, we aimed to identify the regulatory pathway involving the PIK3C3-MAPK14 signaling axis that drives ALI progression by controlling autophagy and macrophage polarization. Using machine learning transcriptomic analysis, MAPK14 was identified as a core gene associated with ALI, and multi-omics integration confirmed its upregulated expression in ALI tissues. MAPK14 localization to pro-inflammatory macrophages was determined using single-cell sequencing. Furthermore, we observed a significant positive correlation between MAPK14 and autophagy-related genes. Molecular docking and kinetic simulations revealed high-affinity interactions between PIK3C3 and MAPK14 (ΔG-bind = -127.722 ± 33.269 kJ/mol). In vitro experiments followed by Western Blot(WB) and RT-q polymerase chain reaction (PCR) assays demonstrated that lipopolysaccharide stimulation upregulated MAPK14 expression through downregulation of PIK3C3 expression, resulting in impaired autophagic flux (LC3-II/Ⅰ↓, TOM20↑, P62↑, HSP60↑). Flow cytometry and enzyme-linked immunosorbent assay (ELISA) confirmed a shift toward pro-inflammatory (M1) macrophage polarization. RNA pull-down assay directly captured the PIK3C3-MAPK14 complex, and functional validation showed that PIK3C3 overexpression significantly inhibited MAPK14 protein expression, whereas PIK3C3 knockdown enhanced it. In conclusion, targeting the PIK3C3-MAPK14 axis is a promising therapeutic strategy for ALI.