Sphingosine-based liposome as DNA vector for intramuscular gene delivery.

PURPOSE

The aim of this study was to develop a labile sphingosine-based liposome for intramuscular gene delivery.

METHODS

Sphingosine-based liposomes were formulated in a range of solutions with phosphatidylcholine, then were associated to DNA. The physico-chemical characteristics of the sphingosine/EPC liposomes and sphingosine/EPC/DNA lipoplexes were determined. DNA stability within sphingosine-based liposomes was evaluated in the presence of a nuclease and mouse serum. In vivo gene transfer was studied by intramuscular injection with and without the electrotransfer technique.

RESULTS

By increasing the charge ratios, colloidally stable sphingosine/DNA particles with a 170 nm average diameter and a positive zeta potential were obtained. Ethidium bromide was still able to insert into plasmid DNA within the lipoplexes, even though plasmid DNA was demonstrated to be complexed to the lipid by gel electrophoresis. Additionally, DNA was shown to be accessible to DNase I, but significantly resistant to serum enzymatic digestion. Upon intramuscular injection, lipoplexes induced an inhibition of gene expression as compared with naked DNA.

CONCLUSIONS

The cationic sphingosine/EPC/DNA complexes form weakly compacted structure, potentially labile in vivo, which might be useful for in vivo gene transfer.