Ocular gene delivery systems using ternary complexes of plasmid DNA, polyethylenimine, and anionic polymers

In this experiment, we developed anionic ternary complexes for effective and safe ocular gene delivery. Ternary complexes were constructed by coating plasmid DNA (pDNA)/polyethylenimine (PEI) complex with anionic polymers such as γ-polyglutamic acid (γ-PGA) and chondroitin sulfate (CS). The cationic pDNA/PEI complex showed high gene expression on the human retinal pigment epithelial cell line, ARPE-19 cells. The pDNA/PEI complexes, however, also showed high cytotoxicity on the cells and aggregated strongly in the vitreous body. On the other hand, the anionic ternary complexes showed high gene expression on ARPE-19 cells without such cytotoxicity and aggregation. After intravitreous administration of the complexes, the anionic ternary complexes showed high gene expression in the retina. These results strongly indicate that anionic ternary complexes are suitable for effective and safe ocular gene therapy.