A ROS-responsive platelet extracellular vesicle biomimetic nanosystem regulates CD36/Fyn-CXCL-NETosis pathway-mediated immune-inflammatory amplification in the treatment of transfusion-related acute lung injury.

Transfusion-related acute lung injury (TRALI) remains a life-threatening complication of blood transfusion, yet the macrophage-neutrophil-NETosis inflammatory amplification mechanism and effective interventions are still incompletely defined. Here, we examined a CD36/Fyn-CXCL-related axis in TRALI and evaluated a ROS-responsive platelet extracellular vesicle biomimetic nanosystem (PEV@SP@EG) as a targeted delivery strategy. In a murine TRALI model, exploratory single-cell transcriptomic analysis showed immune-cell remodeling and linked CD36 expression to M1-like macrophage features. CD36 knockdown or pharmacological inhibition of Fyn/NF-kappaB reduced M1 polarization markers, CXCL production, and ROS generation. Conditioned medium from CD36-overexpressing BMDMs promoted neutrophil migration and NETosis, whereas CXCL-CXCR2 blockade or CD36/Fyn inhibition weakened these responses. PEV@SP@EG showed ROS-triggered drug release and preferential lung enrichment. In vivo, PEV@SP@EG attenuated CD36/Fyn-NF-kappaB-CXCL-related inflammatory signaling, NET formation, and oxidative stress in TRALI lung tissue, with concomitant improvement in lung architecture and gas exchange. These findings support a role for macrophage CD36/Fyn signaling in TRALI-associated macrophage-neutrophil inflammatory crosstalk and suggest that PEV@SP@EG may provide a targeted nanotherapeutic delivery platform for TRALI intervention.