Reassessment of Exosome Composition
Reassessment of Exosome Composition
复制标题
外泌体成分的重新评估
DOI：
10.1016/j.cell.2019.02.029
复制
发表时间：
2019-04-04
期刊：
影响因子：
64.5
通讯作者：
Coffey, Robert J.
中科院分区：
文献类型：
--
作者：
Jeppesen, Dennis K.;Fenix, Aidan M.;Coffey, Robert J.
胞外小泡的异质性和非囊泡胞外物质的存在导致了对外切体的内容和功能性质的争论。在这里，我们使用高分辨率密度梯度分离和直接免疫亲和捕获来精确地表征外体和其他非囊泡材料的RNA、DNA和蛋白质成分。细胞外RNA、RNA结合蛋白和其他细胞蛋白在外体和非囊泡室中差异表达。在外体中未检测到Argavite 1-4、糖酵解酶和细胞骨架蛋白。我们发现膜联蛋白A1是直接从质膜上脱落的微泡的特异性标记物。我们进一步证明，小的胞外小泡不是活跃的DNA释放的载体。相反，我们提出了一个新的模型，通过自噬和多囊泡依赖于内小体但不依赖于外小体的机制来主动分泌细胞外DNA。这项研究证明了重新评估外切体组成的必要性，并为更清楚地了解细胞外小泡的异质性提供了一个框架。
The heterogeneity of small extracellular vesicles and presence of non-vesicular extracellular matter have led to debate about contents and functional properties of exosomes. Here, we employ high-resolution density gradient fractionation and direct immunoaffinity capture to precisely characterize the RNA, DNA, and protein constituents of exosomes and other non-vesicle material. Extracellular RNA, RNA-binding proteins, and other cellular proteins are differentially expressed in exosomes and non-vesicle compartments. Argonaute 1-4, glycolytic enzymes, and cytoskeletal proteins were not detected in exosomes. We identify annexin Al as a specific marker for microvesicles that are shed directly from the plasma membrane. We further show that small extracellular vesicles are not vehicles of active DNA release. instead, we propose a new model for active secretion of extracellular DNA through an autophagy- and multivesicular-endosome-dependent but exosome-independent mechanism. This study demonstrates the need for a reassessment of exosome composition and offers a framework for a clearer understanding of extracellular vesicle heterogeneity.