State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
J Cell Biochem. 2010 Oct 1;111(2):488-96. doi: 10.1002/jcb.22733.
Cells release exosomes to transfer various molecules to other cells. Exosomes are involved in a number of physiological and pathological processes. They are emerging great potential utility for diseases diagnosis and treatment recently. However, the internalization and intracellular trafficking of exosomes have not been described clearly. In this work, exosomes were isolated from the culture medium of PC12 cells, labeled by lipophilic dye and amino-reactive fluorophore, incubated with resting PC12 cells. The results of live-cell microscopy indicated that exosomes were internalized through endocytosis pathway, trapped in vesicles, and transported to perinuclear region. Particle tracking fluorescent vesicles suggested that the active transport of exosomes may be mediated by cytoskeleton. The proteins on exosome membrane were found to be released from exosomes and trapped in lysosome. The inverted transport of lipophilic dye from perinuclear region to cell peripheries was revealed, possibly caused by recycling of the exosome lipids. This study provides new sight into the mechanisms of exosome uptake and intracellular fate.
细胞通过释放外泌体将各种分子转移到其他细胞。外泌体参与了许多生理和病理过程。最近，它们在疾病的诊断和治疗方面具有很大的应用潜力。然而，外泌体的内化和细胞内转运过程还没有被清楚地描述。在这项工作中，我们从 PC12 细胞的培养基中分离出外泌体，用亲脂性染料和反应性荧光团进行标记，然后与静止的 PC12 细胞共孵育。活细胞显微镜的结果表明，外泌体通过内吞作用途径被内化，被捕获在囊泡中，并被运输到核周区域。荧光颗粒追踪实验表明，外泌体的主动运输可能是由细胞骨架介导的。外泌体膜上的蛋白质被发现从外泌体中释放出来，并被捕获在溶酶体中。亲脂性染料从核周区域到细胞外周的反向转运被揭示出来，可能是由于外泌体脂质的再循环。这项研究为外泌体摄取和细胞内命运的机制提供了新的视角。
