Enhanced delivery of naked DNA to the skin by non-invasive in vivo electroporation

Abstract

DNA delivery to skin may be useful for the treatment of skin diseases, DNA vaccinations, and other gene therapy applications requiring local or systemic distribution of a transgene product. However, the effective, consistent and patient-friendly transfection of skin cells remains a challenge. In a mouse model, we evaluated the effectiveness of intradermal injection of plasmid DNA followed by noninvasive in vivo electroporation (EP) as a method to improve transfection in skin. We achieved a several hundred-fold stimulation of gene expression by EP, sufficient to produce clinically relevant amounts of transgene product. We studied the effect of DNA dose and time after treatment as well as various EP pulse parameters on the efficiency of gene expression. EP under conditions of constant charge transfer revealed that the applied voltage was the main determinant for transgene expression efficiency while other pulse parameters had lesser effects. Patient-friendly, noninvasive meander electrodes which we designed for clinical applications proved equally effective and safe as plate electrodes. We also showed for the first time that noninvasive EP is effective in stimulating transfection and gene expression in human skin, particularly in the epidermis. Our findings demonstrate the applicability of EP-enhanced DNA delivery to skin for gene therapy, DNA immunization and other areas.

In vivo gene silencing in solid tumors by targeted electrically mediated siRNA delivery

“…25 This physical technique has been previously used by different groups including ours to locally deliver siRNAs in various tissues. [29][30][31][32][33][34][35][36] As reported previously we observed that the electrical treatment itself had no detectable effect on tumor growth. Takahashi and coworkers 23 recently found that EP following injection in mouse melanoma tumors slightly improved the uptake of a plasmid encoding luciferase and subsequently attempted this approach for treatment of the tumors with siRNAs or plasmids encoding shRNAs.…”

“…In rodents, EP have been used to deliver siRNAs in various organs such as skin, 29 eyes, 30 brain, 31 muscles, 32,33 joint tissue 34,35 and kidney. 36 However, delivery of large nucleic acids (plasmids) have been found to be poorly efficient in solid tumors.…”

Optimization of cutaneous electrically mediated plasmid DNA delivery using novel electrode

“…For electroporation gene delivery to skin, plasmid DNA may be injected intradermally [1][2][3][4][5][6][7][8][9][10] or biolistically. 11 Pulses are applied to the skin surface or through penetrating (needle) electrodes.…”

“…Caliper, plate, tweezer or clip type electrodes grip a fold of skin. 1,[4][5][6]9,10 The meander 7,11 and the N1/ N2 electrode 8 are simply pressed against the injected region. The applied pressure may vary.…”

Vectors for the treatment of autoimmune disease

“…3 Electroporation has since been shown to enhance gene transfer in other tissues including synovium, 4 spinal cord, 5 and skin. 6 Effective delivery of naked DNA to skeletal muscle is also facilitated by the increase in hydrostatic pressure caused by rapid injection of a large volume of DNA intravenously (i.v.) into a limb with occluded blood supply.…”