Faculty of Pharmacy, Division of Pharmaceutical Biosciences, University of Helsinki, 00014 Helsinki, Finland.
Faculty of Pharmacy, Division of Pharmaceutical Biosciences, University of Helsinki, 00014 Helsinki, Finland; Laboratory of Chemistry and Bioengineering, Tampere University of Technology, 33720 Tampere, Finland.
J Control Release. 2018 Aug 28;284:133-143. doi: 10.1016/j.jconrel.2018.06.015. Epub 2018 Jun 15.
In response to physiological and artificial stimuli, cells generate nano-scale extracellular vesicles (EVs) by encapsulating biomolecules in plasma membrane-derived phospholipid envelopes. These vesicles are released to bodily fluids, hence acting as powerful endogenous mediators in intercellular signaling. EVs provide a compelling alternative for biomarker discovery and targeted drug delivery, but their kinetics and dynamics while interacting with living cells are poorly understood. Here we introduce a novel method, fluorescence lifetime imaging microscopy (FLIM) to investigate these interaction attributes. By FLIM, we show distinct cellular uptake mechanisms of different EV subtypes, exosomes and microvesicles, loaded with anti-cancer agent, paclitaxel. We demonstrate differences in intracellular behavior and drug release profiles of paclitaxel-containing EVs. Exosomes seem to deliver the drug mostly by endocytosis while microvesicles enter the cells by both endocytosis and fusion with cell membrane. This research offers a new real-time method to investigate EV kinetics with living cells, and it is a potential advancement to complement the existing techniques. The findings of this study improve the current knowledge in exploiting EVs as next-generation targeted drug delivery systems.
针对生理和人为刺激，细胞通过将生物分子封装在由质膜衍生的磷脂包膜中来产生纳米级别的细胞外囊泡（EVs）。这些囊泡被释放到体液中，因此作为细胞间信号传递的有力内源性介质。EVs 为生物标志物发现和靶向药物输送提供了极具吸引力的替代方案，但它们与活细胞相互作用时的动力学和动态特性仍知之甚少。在这里，我们引入了一种新的方法，即荧光寿命成像显微镜（FLIM）来研究这些相互作用属性。通过 FLIM，我们展示了负载抗癌剂紫杉醇的不同 EV 亚型，即外泌体和微泡的不同细胞摄取机制。我们证明了含有紫杉醇的 EV 在内细胞行为和药物释放特性上的差异。外泌体似乎主要通过内吞作用来输送药物，而微泡通过内吞作用和与细胞膜融合进入细胞。这项研究为研究 EV 与活细胞的动力学提供了一种新的实时方法，是对现有技术的潜在补充。这项研究的结果提高了利用 EV 作为下一代靶向药物输送系统的现有知识水平。
