Plasmid DNA electrotransfer for intracellular and secreted proteins expression: new methodological developments and applications

Abstract

SummaryIn vivo electrotransfer is a physical method of gene delivery in various tissues and organs, relying on the injection of a plasmid DNA followed by electric pulse delivery. The importance of the association between cell permeabilization and DNA electrophoresis for electrotransfer efficiency has been highlighted. In vivo electrotransfer is of special interest since it is the most efficient non-viral strategy of gene delivery and also because of its low cost, easiness of realization and safety. The potentiality of this technique can be further improved by optimizing plasmid biodistribution in the targeted organ, plasmid structure, and the design of the encoded protein. In particular, we found that plasmids of smaller size were electrotransferred more efficiently than large plasmids. It is also of importance to study and understand kinetic expression of the transgene, which can be very variable, depending on many factors including cellular localization of the protein, physiological activity and regulation. The most widely targeted tissue is skeletal muscle, because this strategy is not only promising for the treatment of muscle disorders, but also for the systemic secretion of therapeutic proteins. Vaccination and oncology gene therapy are also major fields of application of electrotransfer, whereas application to other organs such as liver, brain and cornea are expanding. Many published studies have shown that plasmid electrotransfer can lead to long-lasting therapeutic effects in various pathologies such as cancer, blood disorders, rheumatoid arthritis or muscle ischemia. DNA electrotransfer is also a powerful laboratory tool to study gene function in a given tissue.

Ultrasound-contrast agent mediated naked gene delivery in the peritoneal cavity of adult rat

“…8 For nonviral transfection, the naked DNA can be delivered into cells or tissues either by chemical carriers such as liposome and cationic polymers or by physical/ mechanical means exemplified by electroporation. 9,10 Effective use of these methods is limited by the low transfection efficiency, the transient expression of gene product and the lack of organ and tissue specificity. Previous studies have suggested that sonoporation (transient increase in cell membrane permeability by ultrasonic exposure) could be an alternative approach as it is not only rapid, reproducible and relatively inexpensive but also provides a safe, noninvasive and efficient means suitable for in vivo gene delivery.…”

Gene Therapy Progress and Prospects: Electroporation and other physical methods

“…Indeed, a wide range of tissues have been studied including skin, kidney, lung, liver, skeletal and cardiac muscle, joints, spinal cord, brain, retina, cornea and the vasculature. [4][5][6][7] In most studies, electroporation increased gene expression by 100-to 1000-fold compared to injection of naked plasmid DNA. The exact mechanism by which delivery of plasmid into cells is enhanced is not certain, although it is clear that membranes become effectively permeable once a critical voltage has been achieved (in the order of 200 V/cm in vivo).…”

In vivo NMR imaging evaluation of efficiency and toxicity of gene electrotransfer in rat muscle

“…1 Some applications of ET now envisioned are the endogenous synthesis of EPO, 2 of the soluble receptor to TNFa 3 and of the antiinflammatory cytokine IL-10, 4,5 as well as tumour gene therapy, 6,7 restoration of muscle structural proteins, 8 and DNA vaccination. 9 ET is also applied to tumour electrochemotherapy, 10 where protocols with high voltage and short duration pulses allow antitumoral drugs to be locally delivered to tumour cells.…”