Cationic lipids destabilize lysosomal membrane in vitro

• Published in: FEBS letters 1997-11, Vol.417 (2), p.199-202
• Main Authors: Wattiaux, Robert, Jadot, Michel, Warnier-Pirotte, Marie-Thérèse, Wattiaux-De Coninck, Simone
• Format: Article
• Language: English
• Subjects: Animals; beta-Galactosidase - metabolism; Cationic lipid; Cations; Cell-Free System; DNA - chemistry; Fatty Acids, Monounsaturated - chemistry; Hydrogen-Ion Concentration; Intracellular Membranes - chemistry; Lipids - chemistry; Lysosomal membrane destabilization; Lysosomes - chemistry; Male; Plasmids; Quaternary Ammonium Compounds - chemistry; Rats; Rats, Wistar; Transfection - methods
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(97)01283-0

Addition of cationic lipids to plasmid DNA considerably increases the efficiency of transfection. The mechanism has not yet been elucidated. A possibility is that these compounds destabilize biological membranes (plasma, endosomal, lysosomal), facilitating the transfer of nucleic molecules through these membranes. We have investigated the problem by determining if a cationic lipid N-(1-(2,3-dioleoxy)propyl)- N, N, N,-trimethylammonium methyl-sulfate (DOTAP, Boehringer, Mannheim, Germany) affects the integrity of rat liver lysosomal membrane. We have measured the latency of β-galactosidase, a lysosomal enzyme, and found that incubation of lysosomes with low concentrations of DOTAP causes a striking increase in free activity of the hydrolase and even a release of the enzyme into the medium. This indicates that lysosomal membrane is deeply destabilized by the lipid. The phenomenon depends on pH, it is less pronounced at pH 5 than at pH 7.4. Anionic compounds, particularly anionic amphipathic lipids, can to some extent prevent this phenomenon. It can be observed with various cationic lipids. A possible explanation is that cationic liposomes interact with anionic lipids of lysosomal membrane, allowing a fusion between the lipid bilayers which results in a destabilization of the organelle membrane.