title: Polyethylenimine-mediated cellular uptake, nucleus trafficking and expression of cytokine plasmid DNA.
abstract: Although polyethylenimine (PEI) has been widely used as a nonviral vector, there is little mechanistic understanding on PEI-mediated delivery. Here, we studied whether the expression of murine interleukin-2 (mIL-2) plasmids could be improved by complexation with PEI at various N/P ratios, and whether the cellular uptake, nuclear translocation, and retention of plasmids could be affected by the N/P ratios. Compared with the naked mIL-2, PEI/mIL-2 complexes showed at least two orders of magnitude higher expression at Raw264 cells in the N/P ratio-dependent manner. PEI-mediated cellular uptake and nuclear trafficking of plasmids, quantitated by competitive polymerase chain reaction, also depended on the N/P ratios showing the highest cell and nuclear levels of plasmids at 10/1. The higher cellular levels of plasmid DNA after PEI-mediated delivery were also observed in other cell lines. Unlike naked plasmids, PEI/mIL-2 complexes (N/P ratios >/=4/1) showed prolonged cellular and nuclear retention of mIL-2 plasmids. The nuclear translocation and higher cellular level of plasmids given in PEI complexes were similarly observed by fluorescence microscopy. Moreover, PEI/mIL-2 complexes revealed high stability against DNase I, partly explaining the prolonged subcellular retention. These results indicate that the expression of plasmid mIL-2 might be highly enhanced by complexation with PEI and that such increased expression could be attributed by the higher cellular uptake, nuclear translocation and prolonged retention.
authors.affiliation: Department of Microbiology and Institute of Medical Research, College of Medicine, Pochon CHA University, Kyonggi-do, South Korea.
authors.forename: Y-K
authors.initials: YK
authors.lastname: Oh
authors.forename: D
authors.initials: D
authors.lastname: Suh
authors.forename: J M
authors.initials: JM
authors.lastname: Kim
authors.forename: H-G
authors.initials: HG
authors.lastname: Choi
authors.forename: K
authors.initials: K
authors.lastname: Shin
authors.forename: J J
authors.initials: JJ
authors.lastname: Ko
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D018014:Gene Transfer Techniques; D006801:Humans; D018664:Interleukin-12 / Q000235:genetics*; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D010957:Plasmids / Q000378:metabolism*; D011094:Polyethyleneimine; D014178:Translocation, Genetic
chemical_list: D018664:Interleukin-12; D011094:Polyethyleneimine