Moghimi S Moein, Symonds Peter, Murray J Clifford, Hunter A Christy, Debska Grazyna, Szewczyk Adam
Molecular Targeting and Polymer Toxicology Group, School of Pharmacy, University of Brighton, Brighton BN2 4GJ, UK.
Mol Ther. 2005 Jun;11(6):990-5. doi: 10.1016/j.ymthe.2005.02.010.
Poly(ethylenimine) (PEI) is a cationic macromolecule commonly used in gene transfer/therapy protocols with high transfection efficiency both in vitro and in vivo. PEI is also cytotoxic, but the molecular basis of its cytotoxicity is poorly understood. Here, we have demonstrated that branched (25 kDa) and linear (750 kDa) PEI can both induce membrane damage and initiate apoptosis in three clinically relevant human cell lines (Jurkat T cells, umbilical vein endothelial cells, and THLE3 hepatocyte-like cells). We have defined Phase I toxicity as early necrotic-like changes (30 min) resulting from compromised membrane integrity, assessed by considerable lactate dehydrogenase release and phosphatidylserine translocation from the inner plasma membrane to the outer cell surface. Phase II cytotoxicity (24 h) was due to activation of a "mitochondrially mediated apoptotic program," resulting from PEI-induced channel formation in the outer mitochondrial membrane. This led to the release of proapoptotic cytochrome c, subsequent activation of caspase 3, and alteration in mitochondrial membrane potential as a result of caspase translocation into the mitochondria. The reported observations have important implications for the design and execution of gene therapy protocols as well for controlling intracellular distribution of drugs with cationic-based polymer-delivery systems.
聚乙烯亚胺（PEI）是一种阳离子大分子，常用于基因转移/治疗方案，在体外和体内均具有高转染效率。PEI也具有细胞毒性，但其细胞毒性的分子基础尚不清楚。在此，我们证明了分支状（25 kDa）和线性（750 kDa）PEI均可诱导三种临床相关人类细胞系（Jurkat T细胞、脐静脉内皮细胞和THLE3肝样细胞）的膜损伤并引发凋亡。我们将I期毒性定义为由于膜完整性受损导致的早期坏死样变化（30分钟），通过大量乳酸脱氢酶释放以及磷脂酰丝氨酸从质膜内侧转移至细胞外表面来评估。II期细胞毒性（24小时）是由于“线粒体介导的凋亡程序”激活所致，这是由PEI诱导线粒体外膜形成通道引起的。这导致促凋亡细胞色素c释放，随后激活半胱天冬酶3，并由于半胱天冬酶转位至线粒体而导致线粒体膜电位改变。所报道的观察结果对于基因治疗方案的设计和实施以及控制基于阳离子聚合物递送系统的药物在细胞内的分布具有重要意义。
