Production and Use of Gesicles for Nucleic Acid Delivery.

Over-expression of the vesicular stomatitis virus glycoprotein (VSVG) in mammalian cells can induce the formation of VSVG-pseudotyped vesicles (named "gesicles") from membrane budding. Its use as a nucleic acid delivery tool is still poorly documented. Naked-plasmid DNA can be delivered in animal cells with gesicles in presence of hexadimethrine bromide (polybrene). However, little is known about gesicle manufacturing process and conditions to obtain successful nucleic acid delivery. In this study, gesicles production process using polyethylenimine (PEI)-transfected HEK293 cells was developed by defining the VSVG-plasmid concentration, the DNA:PEI mass ratio, and the time of gesicle harvest. Furthermore, parameters described in the literature relevant for nucleic acid delivery such as (i) component concentrations in assembly mixture, (ii) component addition order, (iii) incubation time, and (iv) polybrene concentration were tested by assessing the transfection capacity of the gesicles complexed with a green fluorescent protein (GFP)-coding plasmid. Interestingly, freezing/thawing cycles and storage at + 4 °C, - 20 °C, and - 80 °C did not reduce gesicles' ability to transfer plasmid DNA. Transfection efficiency of 55% and 22% was obtained for HeLa cells and for hard-to-transfect cells such as human myoblasts, respectively. For the first time, gesicles were used for delivery of a large plasmid (18-kb) with 42% of efficiency and for enhanced green fluorescent protein (eGFP) gene silencing with siRNA (up to 60%). In conclusion, gesicles represent attractive bioreagents with great potential to deliver nucleic acids in mammalian cells.