Evaluation of cationic liposomes composed of an amino acid–based lipid for neuronal transfection

We investigated the ability of cationic liposomes composed of 1,5-dihexadecyl N-arginyl-L-glutamate (Arg-Glu2C16) to carry nucleic acids into neuronal cells. Such liposomes have been shown to have a remarkable capacity for transfecting immortalized cell lines. Lipoplexes between the Arg-Glu2C16 liposomes and plasmid DNA encoding green fluorescent protein (GFP) were analyzed in terms of lipoplex formation, intracellular DNA trafficking, transfection efficiency, and cytotoxicity in neuronal SH-SY5Y cells. A maximum number of cells expressing GFP was obtained with lipoplexes at a lipid-to-DNA ratio of 15. With these lipoplexes, 16% of the cells were GFP-positive, which was approximately fourfold higher than the level obtained with a commercially available transfection reagent, Lipofectamine 2000. Furthermore, as a result of the low cytotoxicity of the Arg-Glu2C16 lipoplexes, the proportion of GFP-positive cells could be increased to 25% by increasing the concentration of lipoplexes that was applied to the cells. We have demonstrated that Arg-Glu2C16, as a model cationic amino acid–based lipid, has a high capability as a gene carrier, even for neuronal transfection. In this study, specific cationic liposomes were characterized as nucleic acid transfection agents for neuronal cells. A fourfold higher transfection rate with low cytotoxicity was reported compared to Lipofectamine 2000, a commercial reagent. The authors conclude that the studied cationic liposomes have a high capability as a gene carrier for neuronal transfection. This may become clinically significant in future gene therapy efforts of neuronal diseases.