Exploitation of de novo helper-lipids for effective gene delivery

Purpose. In this experiment, we developed new cationic liposomes as a vector, which form the complex with plasmid DNA (pDNA), for gene delivery after systemic administration. We investigated penetration enhancers as an additional component of the cationic liposomes because of their fusogenic activities. Methods. Transdermal penetraion enhancers such as N-lauroylsarcosine (LS), (R)-(+)-limonene (LM), vitamin E (VE), and phosphatidyl choline from eggs (EggPC) were used in this experiments as helper-lipids with N-[1-(2, 3-dioleyloxy)propyl]-N,N,N-trimethlylammonium chloride (DOTMA) and cholesterol (CHOL). We examined in vitro transfection efficiency, cytotoxicity, hematotoxicity, and in vivo transfection efficiency of pDNA/cationic liposomes complexes. Results. In transfection experiments in vitro, the cationic lipoplexes containing LS had highest transfection efficiency among the other lipoplexes independently of fetal bovine serum (FBS). Furthermore, the lipoplexes containing LS had lowest cell toxicity among the other lipoplexes in the presence of FBS. As the results of erythrocytes interaction experiment, DOTMA / LS / CHOL, DOTMA / VE / CHOL, and DOTMA / EggPC / CHOL lipoplexes showed extremely lower hematotoxicity. On the basis of these results, the in vivo transfection efficiencies of the lipoplexes were examined. The lipoplexes containing LS had the highest transfection activity among the lipoplexes. Conclusion. In conclusion, several transdermal penetration enhancers are available for the helper-lipids in cationic liposomal vectors. Among them, DOTMA/LS/CHOL lipoplexes showed superior characteristics in in vitro transfection efficiency, cell toxicity, hematotoxicity, and in vivo transfection efficiency.