Therapeutic levels of erythropoietin (EPO) achieved after gene electrotransfer to skin in mice

Abstract

Gene electrotransfer refers to gene transfection by electroporation and is an effective non-viral method for delivering naked DNA into cells and tissues. This study presents data from gene electrotransfer with erythropoietin (EPO) to mouse skin. Nine-week-old female NMRI mice received one, two or three intradermal injections of 50 mg EPO plasmid and were subsequently electroporated. With plate electrodes and 100 mg of EPO, a significant increase in hemoglobin (Po0.01) was observed compared with controls. The level of hemoglobin peaked after 5 weeks but stayed significantly elevated for more than 3 months. Serum EPO was significantly increased (Po0.001) 24 h after the transfection and remained significantly different compared with controls until the maximum level of serum EPO was reached after 2 weeks. Eight weeks after the transfection serum EPO returned to baseline. In this study, we have established that gene electrotransfer to skin of even small amounts of DNA can lead to systemically therapeutic levels of protein. This means that in addition to DNA vaccinations, there is a potential utility for electroporation in alleviating systemic diseases such as cancer and protein deficiency disorders.

Duration and level of transgene expression after gene electrotransfer to skin in mice

“…It is capable of expressing genes transfected by electroporation, locally as is the case with Katushka and luciferase, but also systemically, as we have shown with EPO. 33 Compared to gene electrotransfer to muscle, short-term expression must be expected. Muscle cells do not (or seldom) divide, whereas cells in the skin (epidermal and dermal cells) are subject to constant mitotic activity, cell division, cell death and in the case of keratinocytes, desquamation from the surface.…”

“…Evaluation of serum EPO levels after gene electrotransfer to skin with plasmid coding for EPO These studies are described in detail by Gothelf et al 33 The plasmid used was pUHD-EPO controlled by the doxycycline-dependent promoter system Tet-On and Tet-S, and for each EPO injection a solution of 50 mg pUHD-EPO, 50 mg Tet-On and 50 mg Tet-S diluted in 100 ml PBS (final concentration 1.5 mg ml À1 ) was administered.…”

“…We have previously shown that gene electrotransfer with erythropoietin (EPO) to murine skin was able to achieve significant and relevant increase in hemoglobin and serum EPO compared to controls (Gothelf et al, accepted for publication 33 ). We found a statistically significant increase in serum EPO 24 h after the gene electrotransfer procedure, and this increase remained significant until a peak was reached after 2 weeks.…”

The site of administration influences both the type and the magnitude of the immune response induced by DNA vaccine electroporation

“…Electroporation is a non-viral delivery method based on membrane destabilization and DNA electrophoresis, mediated by electric pulses. Efficient delivery of plasmid into muscle, skin, tumor and other tissues using in vivo electroporation has thus been demonstrated [4][5][6][7][8][9][10].…”

Nonviral gene delivery of erythropoietin by mesenchymal stromal cells

“…For example, gene electrotransfer with EPO to mouse skin was shown to provide therapeutic levels of EPO for 3-8 weeks. 23,24 A similar efficiency was achieved as with our cell-based approach, which will benefit from the tropism of MSCs and their additional tissue-supportive effects.…”