Li Wenyu, Liu Yajie, Du Jianwei, Ren Kefeng, Wang Youxiang
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
Nanoscale. 2015 May 14;7(18):8476-84. doi: 10.1039/c4nr07037b.
Cell-penetrating peptides (CPP) have been widely developed as a strategy to enhance cell penetrating ability and transfection. In this work, octa-arginine modified dextran gene vector with pH-sensitivity was developed via host-guest interactions. α-Cyclodextrin was modified with octa-arginine (CDR), which had excellent cell penetrating ability. Dextran was selected as a backbone and modified with azobenzene as guest units by acid-labile imine bonds (Az-I-Dex). The supramolecular polymer CDR/Az-I-Dex with high a C/A molar ratio (molar ratio of CD on CDR to Az on Az-I-Dex) was unfavorable for DNA condensation. The dextran shell of CDR/Az-I-Dex/DNA polyplexes improved the stability under physiological conditions. However, once treated with acetate buffer (pH 5.4) for 3 h, large aggregates formed rapidly due to the cleavage of the dextran shell. As expected, the vector had cell viability of 80% even when the CDR concentration increased to 100 μg mL(-1). Moreover, due to the effective cellular uptake efficiency, CDR/Az-I-Dex/DNA polyplexes had 6-300 times higher transfection efficiency than CDR/DNA polyplexes. It was even higher than high molecular weight PLL-based polyplexes of HEK293 T cells. Importantly, chloroquine as an endosomal escape agent could not improve the transfection of CDR/Az-I-Dex/DNA polyplexes, which indicated that the CDR/Az-I-Dex supramolecular polymer had its own ability for endosomal escape. These results suggested that the CPP-based polyplexes shelled with polysaccharide can be promising non-viral gene delivery carriers.
细胞穿透肽（CPP）已被广泛开发作为一种增强细胞穿透能力和转染的策略。在这项工作中，通过主客体相互作用开发了具有pH敏感性的八聚精氨酸修饰的葡聚糖基因载体。用具有优异细胞穿透能力的八聚精氨酸修饰α-环糊精（CDR）。选择葡聚糖作为主链，并通过酸不稳定的亚胺键（Az-I-Dex）用偶氮苯作为客体单元进行修饰。具有高C/A摩尔比（CDR上的CD与Az-I-Dex上的Az的摩尔比）的超分子聚合物CDR/Az-I-Dex不利于DNA凝聚。CDR/Az-I-Dex/DNA多聚体的葡聚糖外壳提高了生理条件下的稳定性。然而，一旦用醋酸盐缓冲液（pH 5.4）处理3小时，由于葡聚糖外壳的裂解，会迅速形成大的聚集体。正如预期的那样，即使CDR浓度增加到100μg mL(-1)，该载体的细胞活力仍为80%。此外，由于有效的细胞摄取效率，CDR/Az-I-Dex/DNA多聚体的转染效率比CDR/DNA多聚体高6至300倍。它甚至高于基于高分子量聚赖氨酸的HEK293 T细胞多聚体。重要的是，作为内体逃逸剂的氯喹不能提高CDR/Az-I-Dex/DNA多聚体的转染，这表明CDR/Az-I-Dex超分子聚合物具有自身的内体逃逸能力。这些结果表明，基于CPP的多糖包被的多聚体有望成为有前途的非病毒基因递送载体。
