Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
Bioconjug Chem. 2011 Feb 16;22(2):299-306. doi: 10.1021/bc100438m. Epub 2011 Jan 11.
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.
在这项研究中，合成了通过可裂解的二硫键连接的二聚体 siRNA，以实现高效的细胞内递呈和基因沉默。与单体 siRNA 相比，还原二聚体 siRNA 在相同的 N/P 比下与阳离子聚合物表现出远增强的复合物行为，这通过显微镜技术和凝胶特性得到了证明。靶向绿色荧光蛋白 (GFP) 或血管内皮生长因子 (VEGF) 的二聚体 siRNA 与线性聚乙烯亚胺 (LPEI) 复合，并用于各种细胞系以检查基因转染效率。与单体 siRNA/LPEI 复合物相比，二聚体 siRNA/LPEI 复合物在体外显示出大大增强的细胞摄取和基因沉默效果。这些结果主要归因于二聚体 siRNA 更高的电荷密度和促进的链柔韧性，提供了更紧凑和稳定的 siRNA 复合物。此外，还进一步扩展了还原 siRNA 二聚体的缀合策略：合成了聚乙二醇 (PEG) 修饰的二聚体 siRNA 和针对两个不同基因（例如 GFP 和 VEGF）的 siRNA 异二聚体，并对其基因沉默效率进行了表征。二聚体 siRNA 复合体系在体内系统基因治疗中具有很大的潜力。
