A poly(ethylene) glycolylated peptide for ocular delivery compacts DNA into nanoparticles for gene delivery to post-mitotic tissues in vivo.
BACKGROUND
We have previously shown that a novel synthetic peptide for ocular delivery (POD) can efficiently compact DNA and deliver it to cells in vitro. This observation prompted us to develop use of POD as a nonviral vector in vivo.


METHODS
POD peptide was modified using poly(ethylene) glycol (PEG-POD) and used to compact DNA into nanoparticles that were then analysed using electron microscopy, dynamic light scattering, and fluorescent labeling. Transfection efficiency and localization were determined 48 h post-injection into the subretinal space of the mouse eye using luciferase and LacZ, respectively. Efficiency of ocular transfection was compared to two other PEGylated peptides: PEG-TAT and PEG-CK30.


RESULTS
PEG-POD can compact DNA and form discrete nanoparticles of approximately 136 nm that can penetrate and transduce the retinal pigment epithelium (RPE) in vivo. PEG-POD significantly increased expression of plasmid DNA by 215-fold, PEG-TAT by 56.52-fold, and PEG-CK30 by 24.73-fold relative to DNA injected alone. In all cases beta-galactosidase was observed primarily in the RPE layer after subretinal injection. Electrophysiological analyses of PEG-POD transduced retina indicates an absence of PEG-POD-mediated toxicity. PEG-POD can protect plasmid DNA from DNaseI digestion, resulting in significant transfection of the lung after intravenous injection in mice.


CONCLUSIONS
PEG-POD was found to significantly increase gene delivery relative to both DNA alone and other pegylated peptides. These findings highlight the use of pegylated peptides, and specifically PEG-POD, as novel gene delivery vectors.
Read
Sarah Parker
SP
Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111, USA.
Cashman
Siobhan M
SM
Kumar-Singh
Rajendra
R
D000818:Animals; D002460:Cell Line; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure; D003850:Deoxyribonuclease I / Q000378:metabolism; D018014:Gene Transfer Techniques; D006801:Humans; D007275:Injections, Intravenous; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008938:Mitosis; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D010455:Peptides / Q000737:chemistry* / Q000633:toxicity; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000633:toxicity; D020836:Protein Structure, Quaternary; D055213:Retinal Pigment Epithelium / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D014162:Transfection
D010455:Peptides; D011092:Polyethylene Glycols; D004247:DNA; D008156:Luciferases; D003850:Deoxyribonuclease I