Anti-Inflammatory Therapeutic Effect of Adiponectin Gene Delivery Using a Polymeric Carrier in an Acute Lung Injury Model

Purpose Adiponectin (APN) is an adipokine with antiinflammatory and cytoprotective effects. In this study, the therapeutic effect of APN gene delivery using a polymeric carrier was evaluated in an acute lung injury (ALI) model. Methods Polyethylenimine (2 kDa, PEI2K), PEI25K (25 kDa), polyamidoamine (generation 2, PAMG2), dexamethasone-conjugated PEI2k (PEI2K-Dexa), and dexamethasone-conjugated PAMG2 (PAMG2-Dexa) were evaluated in vitro and in vivo as gene carriers. Formation of plasmid DNA (pDNA)/carrier complexes was confirmed by gel retardation and heparin competition assays. Delivery efficiency was measured by a luciferase assay and fluorescence microscopy. In an ALI animal model, pAPN/carrier complexes were delivered by intratracheal administration. Therapeutic effects were evaluated by cytokine assays and hematoxylin and eosin (H&E) staining. Results Gel retardation assays showed that PEI2K-Dexa and PAMG2-Dexa formed complexes with pDNA. In L2 lung epithelial cells, PAMG2-Dexa yielded higher transfection efficiency than PEI2K, PAMG2, PEI25K, lipofectamine, and PEI2K-Dexa. In vivo experiments showed that PAMG2-Dexa delivered DNA more efficiently to lung tissue than PEI2KDexa and PEI25K. Delivery of pAPN/PAMG2-Dexa complexes upregulated APN expression in the lungs of mice with ALI. As a result, the levels of pro-inflammatory cytokines such as TNF-alpha and IL-1 beta were decreased. H&E staining showed that inflammation in the lungs of mice with ALI was reduced by delivery of the APN gene. Conclusion Delivery of the APN gene using PAMG2-Dexa reduced inflammation in the lungs of mice with ALI. The APN gene could be a useful tool in the development of gene therapy for ALI.