Sur ce site

Sur le Web du CNRS

Accueil du site > Publications > Publications 2009 > Why electro-mediated gene delivery works

Why electro-mediated gene delivery works

Jean-Michel Escoffre, Thomas Portet, Cyril Favard, Christelle Rosazz, Justin Teissie, David S. Dean, M.-P. Rols,

Electroporation is a physical method to induce the uptake of therapeutic drugs and DNA, by eukaryotic cells and tissues. The phenomena behind electro-mediated membrane permeabilization to plasmid DNA have been shown to be significantly more complex than those for small molecules. Small molecules cross the permeabilized membrane by diffusion whereas plasmid DNA first interacts with the electropermeabilized part of the cell surface, forming localized aggregates (Golzio, M., J. Teissi\’e, and M. P. Rols. 2002. Direct visualization at the single-cell level of electrically mediated gene delivery. Proc Natl Acad Sci USA 99:1292-1297). The dynamics of this process is still poorly understood because direct observations have been limited to time scales exceeding several seconds. Here, cells are electropermeabilized in the presence of plasmid DNA and monitored with a temporal resolution of 2 ms. This allows us to show that during the first pulse application, plasmid complexes, or aggregates, start to form at distinct sites on the cell membrane. FRAP measurements show that the positions of these sites are remarkably immobile during the application of further pluses. We find that the actin cytoskeleton does not seem to play a role in the initial formation of DNA/membrane interaction sites but it may be important in the subsequent intracellular DNA traffic. A theoretical model is proposed to explain the appearance of distinct interaction sites, the quantitative increase in DNA and also their immobility , leading to a tentative explanation for the success of electro-mediated gene delivery.