Hypothesis: naked plasmid DNA is taken up by cellsin vivo by a receptor-mediated process

Gene Therapy Progress and Prospects: Electroporation and other physical methods

“…Movement into the cytoplasm was relatively slow and continued after the application of the electrical field ended. This is consistent with the DNA active uptake mechanism proposed by Budker et al, 9 but may represent a novel physical interaction with the cell membrane as, with time, the plasmid that had not yet entered the cytoplasm became inaccessible to a DNA dye. However, this plasmid accumulation has yet to be observed in vivo and the complex organization of tissues such as muscle may significantly modify this process.…”

“…This in turn allows hydrostatic pressure to act on the hepatocyte cell membranes causing transient pores or defects, a process they term hydroporation. Other groups [35][36][37] have demonstrated that the dynamics of the transfection process support this concept of transient hyperpermeability of the hepatocyte cell membrane and do not support the active uptake mechanism proposed by Budker et al 9 The use of this hydrodynamic technique in the mouse has allowed comparison of the effect of different vector sequences, 38 the testing of optimal expression constructs 39 and the efficient delivery of siRNA to the Electroporation and other physical methods DJ Wells liver. 40,41 The same technique has been applied to rats.…”

Hydroporation as the mechanism of hydrodynamic delivery

“…25 It is appropriate to point out that how DNA crosses the plasma membrane and enters the hepatocytes has been a critical issue in the past few years with respect to the hydrodynamic delivery. Budker et al 26 have hypothesized that DNA entry is mediated by unidentified receptors on the hepatocytes. Their hypothesis was based on an observation that the reporter gene expression decreased by approximately 10-50% when dextran sulfate, salmon sperm DNA, or heparin was coinjected with reporter containing plasmid DNA.…”

DNA electrotransfer: its principles and an updated review of its therapeutic applications

“…(i) The simplest, of course, is the injection of naked DNA, which in the skeletal or cardiac muscle leads to some expression of the injected genes; [1][2][3] however, this expression is very low and very variable from sample to sample. (ii) The hydrodynamic method consists in the very rapid injection through the mouse tail vein of a large volumes of DNA solution: it results in a very efficient transfection of liver cells, even though the procedure is somehow dangerous for the treated mice; [4][5][6] indeed, part of the mechanism is based on the transient heart failure resulting from the injection, which blocks the fluid distribution in the body and provokes a liquid overpressure in the liver.…”