Liposomes, artificial phospholipid vesicles, have been developed as a non-viral drug delivery system to allow contained agents to be efficiently delivered to target sites via systemic circulation. Liposomes have been used as a gene transfer tool with cultured cells; however, their precise trafficking and processing remain uncertain. Furthermore, liposomes with different surface charges are known to exhibit distinct properties. The purpose of the current study was to elucidate the intracellular trafficking and processing of liposomes with anionic and cationic surface charges from a morphological view point. We found that cationic liposomes (CLs) were more effectively taken by the cells than anionic liposomes (ALs). Confocal laser scanning microscopy and transmission electron microscopy demonstrated distinct intracellular localization and processing patterns of ALs and CLs. ALs and their contents were localized in lysosomes but not in cytosol, indicating that ALs are subjected to the endosome-lysosome system. In contrast, contents of CLs were distributed mainly in the cytosol. CLs appear to disturb the cell membrane and then collapse to release their contents into the cytosol. It is feasible that the contents of CLs enter the cytosol directly rather than via the endosome-lysosome system.

中文翻译：

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阴离子和阳离子脂质体在培养细胞中运输和加工的形态学分析。

脂质体（人工磷脂囊泡）已开发为一种非病毒药物递送系统，可以使所含药物通过全身循环有效地递送至目标部位。脂质体已被用作培养细胞的基因转移工具。但是，它们的确切贩运和加工仍不确定。此外，已知具有不同表面电荷的脂质体表现出不同的性质。当前研究的目的是从形态学角度阐明具有阴离子和阳离子表面电荷的脂质体的细胞内运输和加工。我们发现阳离子脂质体（CLs）比阴离子脂质体（ALs）更有效地被细胞吸收。共聚焦激光扫描显微镜和透射电子显微镜显示出AL和CL的不同的细胞内定位和加工模式。ALs及其含量位于溶酶体中，而不位于胞质溶胶中，表明ALs受到内体-溶酶体系统的作用。相反，CL的含量主要分布在细胞质中。CL似乎会干扰细胞膜，然后崩溃以将其内容物释放到细胞质中。CL的含量直接进入细胞质而不是通过内体-溶酶体系统进入细胞质是可行的。CL似乎会干扰细胞膜，然后崩溃以将其内容物释放到细胞质中。CL的含量直接进入细胞质而不是通过内体-溶酶体系统进入细胞质是可行的。CL似乎会干扰细胞膜，然后崩溃以将其内容物释放到细胞质中。CL的含量直接进入细胞质而不是通过内体-溶酶体系统进入细胞质是可行的。