# Inhalable PD-L1-engineered hybrid cellular vesicles suppress excessive neutrophil activation and restore mitochondrial homeostasis to alleviate ischemia–reperfusion lung injury and pneumonia

## TL;DR

A new inhalable treatment using engineered vesicles reduces lung injury and pneumonia by targeting inflammation, restoring mitochondria, and improving lung function.

## Contribution

A biohybrid nanovesicle system combining neutrophil targeting, PD-L1, and resveratrol for multi-target treatment of lung injury and pneumonia.

## Key findings

- Res-PD-L1@nmEVs reduced inflammation, oxidative stress, and restored mitochondrial function in lung epithelial cells.
- Nebulized delivery suppressed neutrophil activation and improved alveolar barrier integrity in rat models.
- Transcriptomic analysis showed enhanced energy metabolism and reduced inflammatory signaling after treatment.

## Abstract

Lung ischemia-reperfusion injury and severe pneumonia represent major clinical challenges with high mortality rates and a lack of effective targeted therapies after lung transplant. Their pathogenesis involves multiple factors, including immune dysregulation, oxidative stress, and mitochondrial dysfunction, which limit the efficacy of single-target treatment strategies. This study developed a novel biohybrid nanovesicle system (Res-PD-L1@nmEVs) that integrates the inflammatory targeting capability of neutrophil membrane-derived vesicles, the tissue repair and immunomodulatory functions of PD-L1-overexpressing mesenchymal stem cell extracellular vesicles, and the mitochondrial protective effects of resveratrol. Following nebulized administration, the system demonstrated enhanced pulmonary accumulation and efficient uptake by injured epithelial cells. In vitro experiments confirmed that Res-PD-L1@nmEVs inhibited inflammation and oxidative stress, reduced apoptosis, and restored mitochondrial integrity by activating PINK1-mediated mitophagy and promoting mitochondrial repair, thereby mitigating hypoxia-reoxygenation-induced injury in lung epithelial cells. The delivery of PD-L1 via Res-PD-L1@nmEVs binding to PD-1 on neutrophil membranes suppressed neutrophil activation and alleviated the release of inflammatory factors. In rat models of lung ischemia-reperfusion injury and methicillin-resistant Staphylococcus aureus-induced pneumonia, nebulized administration of Res-PD-L1@nmEVs significantly attenuated lung tissue damage, inhibited neutrophil activation, reduced inflammatory cytokine release, improved alveolar barrier integrity, promoted the recovery of pulmonary function, and alleviated hypoxemia. Transcriptomic analysis revealed that the treatment synergistically enhanced energy metabolism and biosynthetic processes while suppressing inflammatory pathways. This study presents a comprehensive targeted strategy that simultaneously addresses immune dysregulation, oxidative damage, and metabolic dysfunction in inflammatory lung diseases, demonstrating significant potential for clinical translation.

A biohybrid nanovesicle system (Res-PD-L1@nmEVs), composed of neutrophil-targeting and PD-L1-overexpression fused extracellular vesicles which was loaded with mitochondrial protectional resveratrol, was delivered via nebulization for lung ischemia-reperfusion injury and severe pneumonia. The system accumulated in injured lung tissue, suppressed neutrophil activation and inflammation, restored mitochondrial integrity via PINK1-mediated mitophagy, and improved alveolar barrier function. In rat models, treatment reduced lung damage, enhanced pulmonary function, and modulated transcriptomic profiles toward increased energy metabolism and decreased inflammatory signaling, offering a multi-target therapeutic strategy for inflammatory lung diseases.Image 1

•Neutrophil membrane–coated PD-L1 hybrid vesicles enable lung injury targeting.•Nebulized delivery suppresses neutrophil overactivation via PD-1/PD-L1 signaling.•Biohybrid nanovesicles suppresses inflammation, oxidative stress injury, and restore mitochondrial homeostasis.•Therapy alleviates ischemia–reperfusion lung injury and severe pneumonia in vivo.

Neutrophil membrane–coated PD-L1 hybrid vesicles enable lung injury targeting.

Nebulized delivery suppresses neutrophil overactivation via PD-1/PD-L1 signaling.

Biohybrid nanovesicles suppresses inflammation, oxidative stress injury, and restore mitochondrial homeostasis.

Therapy alleviates ischemia–reperfusion lung injury and severe pneumonia in vivo.