Liang Bing, He Ming-Liang, Xiao Zhong-Peng, Li Yi, Chan Chu-Yan, Kung Hsiang-Fu, Shuai Xin-Tao, Peng Ying
Department of Neurology, The Second Affiliated Hospital, Sun Yat-sen University, No. 107, West Yanjiang Road, Guangzhou 510120, China.
Biochem Biophys Res Commun. 2008 Mar 21;367(4):874-80. doi: 10.1016/j.bbrc.2008.01.024. Epub 2008 Jan 15.
A great challenge for gene therapy is to develop a high efficient gene delivery system with low toxicity. Nonviral vectors are still attractive although the current agents displayed some disadvantages (i.e., low transfection efficiency, high toxicity). To overcome the high toxicity of poly(ethylene imine) (PEI) and low transfection efficiency of PEGylated PEI (PEG-PEI), we linked a cell specific target molecule folate (FA) on poly(ethylene glycol) (PEG) and then grafted the FA-PEG onto hyperbranched PEI 25kDa. The FA-PEG- grafted-hyperbranched-PEI (FA-PEG-PEI) effectively condensed plasmid DNA (pDNA) into nanoparticles with positive surface charge under a suitable N/P ratio. Tested in deferent cell lines (i.e., HEK 293T, glioma C6 and hepatoma HepG2 cells), no significant cytotoxicity of FA-PEG-PEI was added to PEG-PEI. More importantly, significant transfection efficiency was exhibited in FA-targeted cells. Reporter assay showed that FA-PEG-PEI/pDNA complexes had significantly higher transgene activity than that of PEI/pDNA in folate-receptor (FR) positive (HEK 293T and C6) cells but not FR-negative (HepG2) cells. These results indicated that FA-PEG-PEI might be a promising candidate for gene delivery with the characteristics of good biocompatibility, potential biodegradability, and relatively high gene transfection efficiency.
基因治疗面临的一个巨大挑战是开发一种低毒性的高效基因递送系统。尽管目前的非病毒载体存在一些缺点（如转染效率低、毒性高），但它们仍然具有吸引力。为了克服聚乙烯亚胺（PEI）的高毒性和聚乙二醇化聚乙烯亚胺（PEG-PEI）的低转染效率，我们将细胞特异性靶向分子叶酸（FA）连接到聚乙二醇（PEG）上，然后将FA-PEG接枝到25kDa的超支化PEI上。在合适的N/P比下，FA-PEG接枝的超支化PEI（FA-PEG-PEI）能有效地将质粒DNA（pDNA）浓缩成具有正表面电荷的纳米颗粒。在不同细胞系（即人胚肾293T细胞、胶质瘤C6细胞和肝癌HepG2细胞）中进行测试，FA-PEG-PEI与PEG-PEI相比没有显著的细胞毒性。更重要的是，在FA靶向的细胞中表现出显著的转染效率。报告基因检测表明，在叶酸受体（FR）阳性（HEK 293T和C6）细胞中，FA-PEG-PEI/pDNA复合物的转基因活性明显高于PEI/pDNA复合物，但在FR阴性（HepG2）细胞中并非如此。这些结果表明，FA-PEG-PEI可能是一种有前景的基因递送候选物，具有良好的生物相容性、潜在的生物可降解性和相对较高的基因转染效率。
