title: Supramolecular control of polyplex dissociation and cell transfection: efficacy of amino groups and threading cyclodextrins in biocleavable polyrotaxanes.
abstract: A novel strategy for gene delivery using biocleavable polyrotaxanes, in which dimethylaminoethyl-modified alpha-cyclodextrins (DMAE-alpha-CDs) are threaded onto a poly(ethylene glycol) (PEG) chain capped with benzyloxycarbonyl-L-tyrosine via disulfide linkages (DMAE-SS-PRX), involves the formation of a stable polyion complex (polyplex) against a counter polyanion and the intracellular plasmid DNA (pDNA) release from the polyplex accompanied by the supramolecular dissociation of DMAE-SS-PRXs. In this study, we prepared biocleavable polyrotaxanes with different numbers of threading alpha-CD and amino (DMAE) groups to enhance the transfection activity of DMAE-SS-PRXs. 29DMAE-alpha18-SS-PRX, in which the numbers of alpha-CD molecules and amino groups were 18 and 29 respectively, exhibited a high transfection activity compared with other PRXs. The transfection activity of DMAE-SS-PRXs seems to be related to the efficacy of pDNA release from those polyplexes, which was controlled by the number of alpha-CD and/or amino groups in the polyrotaxane carrier. Most of the DMAE-SS-PRX polyplexes released the pDNA only in the presence of both 10 mM DTT and of the counter-polyanion, as expected, except for 14DMAE-alpha18-SS-PRX, which released pDNA in the absence of dextran sulfate once the DTT had been added to the polyplex solution. The transfection activity of 14DMAE-alpha18-SS-PRX was significantly lower than that of 29DMAE-alpha18-SS-PRX regardless of the above features. Confocal laser scanning microscopic (CLSM) observation suggested that the specific result for 14DMAE-alpha18-SS-PRX might be due to a premature release of pDNA from the most dissociative 14DMAE-alpha18-SS-PRX polyplex in the cytosol. Therefore, transfection activity seems to be related to an appropriate timing of pDNA release.
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamashita
authors.forename: Daizo
authors.initials: D
authors.lastname: Kanda
authors.forename: Ryo
authors.initials: R
authors.lastname: Katoono
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Yui
authors.forename: Tooru
authors.initials: T
authors.lastname: Ooya
authors.forename: Atsushi
authors.initials: A
authors.lastname: Maruyama
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Akita
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kogure
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Harashima
mesh_terms: D000588:Amines / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D004247:DNA / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics; D004220:Disulfides / Q000737:chemistry; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry*; D004355:Drug Stability; D004587:Electrophoresis, Agar Gel; D018014:Gene Transfer Techniques; D051379:Mice; D041681:NIH 3T3 Cells; D010957:Plasmids / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000737:chemistry; D043862:Rotaxanes / Q000138:chemical synthesis / Q000737:chemistry*; D014162:Transfection / Q000379:methods*; D047391:alpha-Cyclodextrins / Q000737:chemistry*
chemical_list: D000588:Amines; D001672:Biocompatible Materials; D004220:Disulfides; D004337:Drug Carriers; D043862:Rotaxanes; D047391:alpha-Cyclodextrins; D011092:Polyethylene Glycols; D004247:DNA