Abstract Rationale Pediatric acute respiratory distress syndrome (PARDS), a severe complication of acute lung Injury (ALI), is associated with significant morbidity and mortality in children. Currently, there are no specific treatments available for pediatric ARDS. Endothelial cell (EC) dysfunction plays a central role in the pathophysiology of PARDS and is exacerbated by inflammatory responses, leading to impaired barrier function and long-term respiratory complications. Existing therapies for neonatal lung injury are limited to supportive measures, which mitigate symptoms but do not directly protect the pulmonary EC. Therefore, delivering therapeutic mRNA via pulmonary endothelial-targeted nanoparticles may offer a novel and effective strategy for the treatment of PARDS. Methods PARDS was induced by systemic sepsis via the intraperitoneal administration of Lipopolysaccharide (LPS). Pulmonary endothelial-targeting nanoparticles (NPs) were used to intravenously deliver the stabilized FOXF1 mRNA. The targeting efficiency of nanoparticles in both healthy and septic neonatal mice was assessed using an In Vivo Imaging System (IVIS) and flow cytometry. Pulmonary EC damage and the protective efficacy of FOXF1 mRNA NP were evaluated by flow cytometry, Evans Blue extravasation, histology and immunostaining of lung tissue sections, and qRT-PCR. Apoptosis in PARDS mouse pulmonary ECs and the anti-apoptotic function of FOXF1 mRNA were confirmed by flow cytometry of Annexin V staining both in vivo and in vitro. Single-cell RNAseq, ChIP-Seq analysis, and immunofluorescent staining were used to investigate the molecular mechanisms of the FOXF1 gene therapy in PARDS. Results Systemic sepsis causes strong inflammatory responses in the lung, which leads to PARDS and pulmonary EC apoptosis. This further leads to vascular leakage and impaired lung functions. Our NP delivery system delivered nucleic acids, including FOXF1 mRNA, to pulmonary ECs, specifically under PARDS conditions, without accumulation in other organs or cell types. FOXF1 expression is markedly reduced in PARDS and restoring FOXF1 levels significantly improved EC barrier function and mice survival. Moreover, FOXF1 transcriptional activated Bcl2, an anti-apoptotic gene that is downregulated in pulmonary ECs after the lung injury. The restoration of FOXF1 level via nanoparticles enhanced Bcl2 levels and reduces EC apoptosis in PARDS. Conclusion Targeted delivery of FOXF1 mRNA using pulmonary endothelial-specific nanoparticles restores endothelial function in a mouse model of PARDS. This strategy not only promotes pulmonary EC recovery after injury but also protects ECs from apoptosis. Overall, it represents a promising precision gene therapy approach for the treatment of PARDS. This abstract is funded by: NIH
Deng et al. (Fri,) studied this question.