title: Reducible siRNA dimeric conjugates for efficient cellular uptake and gene silencing.
abstract: In this study, dimerized siRNAs linked by a cleavable disulfide bond were synthesized for efficient intracellular delivery and gene silencing. The reducible dimerized siRNAs showed far enhanced complexation behaviors with cationic polymers as compared to monomeric siRNA at the same N/P ratio, as demonstrated by microscopic techniques and gel characterization. Dimerized siRNAs targeting green fluorescent protein (GFP) or vascular endothelial growth factor (VEGF) were complexed with linear polyethylenimine (LPEI), and treated to various cell lines to examine gene transfection efficiencies. In comparison to monomer siRNA/LPEI complexes, dimeric siRNA/LPEI complexes showed greatly enhanced cellular uptake and gene silencing effects in vitro. These results were mainly due to the higher charge density and promoted chain flexibility of the dimerized siRNAs, providing more compact and stable siRNA complexes. In addition, the conjugation strategy of reducible siRNA dimers was further extended: poly(ethylene glycol) (PEG)-modified dimerized siRNAs and heterodimers of siRNAs targeting two different genes (e.g., GFP and VEGF) were synthesized, and their gene silencing efficiencies were characterized. The dimerized siRNA complex system holds great potential for in vivo systemic gene therapy.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Chung
authors.forename: Cheol Am
authors.initials: CA
authors.lastname: Hong
authors.forename: Soo Hyeon
authors.initials: SH
authors.lastname: Lee
authors.forename: Sung Duk
authors.initials: SD
authors.lastname: Jo
authors.forename: Tae Gwan
authors.initials: TG
authors.lastname: Park
mesh_terms: D019281:Dimerization; D004220:Disulfides / Q000737:chemistry / Q000493:pharmacokinetics*; D016503:Drug Delivery Systems; D020868:Gene Silencing; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008958:Models, Molecular; D011092:Polyethylene Glycols / Q000737:chemistry / Q000493:pharmacokinetics; D034741:RNA, Small Interfering / Q000737:chemistry / Q000493:pharmacokinetics*; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry / Q000235:genetics*
chemical_list: D004220:Disulfides; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; D049452:Green Fluorescent Proteins; D011092:Polyethylene Glycols