Institute of Chemical Biology and Pharmaceutical Chemistry, Zhejiang University, Hangzhou 310028, PR China.
Biomaterials. 2012 Feb;33(4):1135-45. doi: 10.1016/j.biomaterials.2011.10.023. Epub 2011 Nov 8.
Polyethylenimine (PEI) - based polymers are promising cationic nanovectors. A good understanding of the mechanism by which cationic polymers/DNA complexes are internalized and delivered to nuclei helps to identify which transport steps may be manipulated in order to improve the transfection efficiency. In this work, cell internalization and trafficking of PEI-CyD (PC) composed of β-cyclodextrin (β-CyD) and polyethylenimine (PEI, Mw 600) are studied. The results show that the PC transfected DNA is internalized by binding membrane-associated proteoglycans. The endocytic pathway of the PC particles is caveolae- and clathrin-dependent with both pathways converging to the lysosome. The intracellular fate of the PC provides visual evidence that it can escape from the lysosome. Lysosomal inhibition with chloroquine has no effect on PC mediated transfection implying that blocking the lysosomal traffic does not improve transfection. To improve the nuclear delivery of PC transfected DNA, nuclear localization signal (NLS) peptides are chosen to conjugate and combine with the PC. Compared to PC/pDNA, PC-NLS/pDNA, and PC/pDNA/NLS can effectively improve gene transfection in dividing and non-dividing cells.
基于聚亚乙基亚胺（PEI）的聚合物是很有前途的阳离子纳米载体。深入了解阳离子聚合物/DNA 复合物被内化并递送至细胞核的机制有助于确定可以操纵哪些运输步骤以提高转染效率。在这项工作中，研究了由β-环糊精（β-CyD）和聚亚乙基亚胺（PEI，Mw 600）组成的 PEI-CyD（PC）的细胞内化和运输。结果表明，PC 转染的 DNA 通过与膜相关的蛋白聚糖结合而被内化。PC 颗粒的内吞途径是网格蛋白和小窝依赖的，这两种途径都汇聚到溶酶体。PC 的细胞内命运提供了视觉证据表明它可以从溶酶体中逃逸。溶酶体抑制氯喹对 PC 介导的转染没有影响，这意味着阻断溶酶体运输并不能提高转染效率。为了提高 PC 转染 DNA 的核递呈，选择核定位信号（NLS）肽进行缀合并与 PC 结合。与 PC/pDNA 相比，PC-NLS/pDNA 和 PC/pDNA/NLS 可以有效提高有丝分裂和非有丝分裂细胞中的基因转染。
