Effect of Polyethyleneglycol Spacer on the Binding Properties of Nuclear Localization Signal-Modified Liposomes to Isolated Nucleus


The nuclear delivery process is a crucial barrier to successful gene delivery, especially in non-dividing cells. We previously proposed a novel strategy for the nuclear delivery of plasmid DNA (pDNA), in which the pDNA is encapsulated in lipid bilayers that had been modified with nucleus-targeting signals, including nuclear localizing signals derived from SV40 (NLS) or sugar units. In the present study, we report on an investigation of the effect of the topology of the liposome-modified NLS on its ability to bind to the isolated nucleus. NLS was directly attached to a liposome (NLS-Lip) by incorporating stearylated NLS (STR-NSL), or by modification with a polyethyleneglycol (PEG) spacer (NLS-PEG-Lip). NLS-unmodified liposomes (PEG-Lip) were used as a control. The liposomes, after labeling with 7-nitrobenz-2-oxa-1,3-diazole (NBD), were incubated with a cell homogenate derived from JAWS II cells, followed by isolation of the nuclear fraction by centrifugation. The PEG-Lip preparation showed negligible binding to the nucleus. In contrast, the binding of NLS-Lips to the nucleus gradually increased in a STR-NLS density-dependent manner. Interestingly, the binding of NLS-PEG-Lips to the nucleus is highly effective even at low density, suggesting that the presence of the PEG spacer is an important factor in improving the binding activity of NLS-modified liposomes to the nucleus. This information will be useful for the design of nucleus-targeting carriers.


Harashima Hideyoshi Faculty of Pharmaceutical Sciences, Hokkaido University
Akita Hidetaka Lab. For Molecular Design Of Pharmaceutics Fac. Of Pharmaceutical Sciences Hokkaido Univ.
FUTAKI Shiroh Institute for Chemical Research, Kyoto University
Akita Hidetaka Graduate School Of Pharmaceutical Sciences Hokkaido University
Harashima Hideyoshi Faculty Of Pharmaceutical Science The University Of Tokushima
Futaki Shiroh Institute For Chemical Research Kyoto University
Kurihara Dai Faculty of Pharmaceutical Sciences, Hokkaido University
Akita Hidetaka Faculty of Pharmaceutical Sciences, Hokkaido University
Kudo Asako Faculty of Pharmaceutical Sciences, Hokkaido University
Masuda Tomoya Faculty of Pharmaceutical Sciences, Hokkaido University