Department of Cellular Computational and Integrative Biology (CIBIO) University of Trento Trento Italy.
J Extracell Vesicles. 2020 Dec;10(2):e12043. doi: 10.1002/jev2.12043. Epub 2020 Dec 28.
Extracellular vesicles (EVs) are heterogeneous membranous particles released from the cells through different biogenetic and secretory mechanisms. We now conceive EVs as shuttles mediating cellular communication, carrying a variety of molecules resulting from intracellular homeostatic mechanisms. The RNA is a widely detected cargo and, impressively, a recognized functional intermediate that elects EVs as modulators of cancer cell phenotypes, determinants of disease spreading, cell surrogates in regenerative medicine, and a source for non-invasive molecular diagnostics. The mechanistic elucidation of the intracellular events responsible for the engagement of RNA into EVs will significantly improve the comprehension and possibly the prediction of EV "quality" in association with cell physiology. Interestingly, the application of multidisciplinary approaches, including biochemical as well as cell-based and computational strategies, is increasingly revealing an active RNA-packaging process implicating RNA-binding proteins (RBPs) in the sorting of coding and non-coding RNAs. In this review, we provide a comprehensive view of RBPs recently emerging as part of the EV biology, considering the scenarios where: individual RBPs were detected in EVs along with their RNA substrates, RBPs were detected in EVs with inferred RNA targets, and EV-transcripts were found to harbour sequence motifs mirroring the activity of RBPs. Proteins so far identified are members of the hnRNP family (hnRNPA2B1, hnRNPC1, hnRNPG, hnRNPH1, hnRNPK, and hnRNPQ), as well as YBX1, HuR, AGO2, IGF2BP1, MEX3C, ANXA2, ALIX, NCL, FUS, TDP-43, MVP, LIN28, SRP9/14, QKI, and TERT. We describe the RBPs based on protein domain features, current knowledge on the association with human diseases, recognition of RNA consensus motifs, and the need to clarify the functional significance in different cellular contexts. We also summarize data on previously identified RBP inhibitor small molecules that could also be introduced in EV research as potential modulators of vesicular RNA sorting.
细胞外囊泡 (EVs) 是通过不同的生物发生和分泌机制从细胞中释放的异质膜性颗粒。我们现在将 EVs 视为介导细胞通讯的载体，携带源自细胞内稳态机制的各种分子。RNA 是广泛检测到的货物，令人印象深刻的是，它是一种公认的功能中间产物，使 EVs 成为癌细胞表型的调节剂、疾病传播的决定因素、再生医学中的细胞替代品，以及非侵入性分子诊断的来源。阐明负责将 RNA 纳入 EVs 的细胞内事件的机制，将显著提高对 EV“质量”的理解，并可能预测其与细胞生理学的关联。有趣的是，应用包括生化、基于细胞和计算策略在内的多学科方法，越来越多地揭示了一种活跃的 RNA 包装过程，涉及 RNA 结合蛋白 (RBPs) 对编码和非编码 RNA 的分类。在这篇综述中，我们提供了最近作为 EV 生物学一部分出现的 RBPs 的综合视图，考虑了以下情况：
单独的 RBPs 与它们的 RNA 底物一起在 EV 中被检测到；
在 EV 中检测到 RBPs，推断出 RNA 靶标；
发现 EV 转录本具有反映 RBPs 活性的序列基序。迄今为止鉴定的蛋白质是 hnRNP 家族的成员（hnRNPA2B1、hnRNPC1、hnRNPG、hnRNPH1、hnRNPK 和 hnRNPQ），以及 YBX1、HuR、AGO2、IGF2BP1、MEX3C、ANXA2、ALIX、NCL、FUS、TDP-43、MVP、LIN28、SRP9/14、QKI 和 TERT。我们根据蛋白质结构域特征、与人类疾病的关联、RNA 保守基序的识别以及在不同细胞环境中澄清功能意义的需要来描述 RBPs。我们还总结了先前鉴定的 RBP 抑制剂小分子的数据，这些小分子也可以作为 EV 研究中的潜在囊泡 RNA 分类调节剂引入。
