Movement of RNA between animal cells

描述(申请人提供)：使用双链RNA(DsRNA)来触发RNA干扰，从而使匹配的疾病基因沉默，作为治疗许多人类疾病的方法正在进行中。然而，将这些基于RNA的药物输送到人类细胞是困难的。相比之下，当dsRNA被引入植物和一些动物(如线虫)的一个细胞中时，由于被称为移动RNA的dsRNA形式在细胞之间的传输，远处细胞中的基因也被沉默。这种RNA在细胞间的直接运输代表了一种新的细胞间信号传递形式，这种信号是在线虫和植物的基因沉默研究中意外发现的。在细胞核中转录的核糖核酸是如何从动物细胞中分泌出来，以沉默远处细胞中的目标基因的，S并不是很清楚。对线虫的研究发现，摄取移动RNA所需的保守蛋白质表明，包括哺乳动物在内的其他动物也可能存在类似的机制。有趣的是，在人类血液中发现了大量的细胞外RNA，并将其作为诊断工具来评估内部器官的疾病状态，这些器官可能是此类RNA的来源。这项提议的目标是利用线虫中可用的工具来揭示dsRNA是如何被修饰以产生从细胞中分泌的可移动RNA，并分析控制这种RNA从细胞中输出的基因。利用现有的突变体，我们将采用生化和遗传学的方法来鉴定修饰的dsRNA和由它们产生的移动RNA。我们将使用我们分离出的在RNA细胞间运输方面存在缺陷的新突变体来发现控制这一过程的其他基因并对其进行分析。这些目标的完成可以揭示RNA是如何被修饰以从动物细胞输出的，并可以开始通过在动物细胞之间直接运输RNA来组装细胞间信号传递的途径。这些研究也有助于理解完全未知的细胞外RNA生物学，它可以成为内脏疾病的强大诊断工具。最后，如果我们了解对dsRNA和其他细胞机制的哪些修改能够使移动RNA有效地进入线虫细胞，我们就可以设计类似的修改后的dsRNA，以便高效地运送到人类细胞中，进行基于RNA干扰的治疗。

DESCRIPTION (provided by applicant): The use of double-stranded RNA (dsRNA) to trigger RNA interference and thereby silence matching disease genes is being pursued as a therapeutic approach for many human diseases. However, it is difficult to deliver these RNA-based drugs into human cells. In contrast, when dsRNA is introduced into one cell in plants and in some animals such as the worm C. elegans, genes in distant cells are also silenced due to the transport between cells of forms of dsRNA called mobile RNA. This direct transport of RNA between cells represents a novel form of intercellular signaling that was accidentally discovered as part of gene silencing studies in the worm C. elegans and in plants. How RNA that is transcribed in the nucleus is secreted from animal cells to silence a target gene in distant cells s not well understood. Studies in C. elegans identified conserved proteins required for the uptake of mobile RNAs suggesting that similar mechanisms may exist in other animals, including mammals. Intriguingly, populations of extracellular RNAs have been found in human blood and are being pursued as diagnostic tools to assess the disease state of internal organs, which are presumably the source of such RNAs. The goals of this proposal are to use the tools available in C. elegans to uncover how dsRNA is modified to generate mobile RNAs that are secreted from cells and to analyze genes that control the export of such RNAs from cells. Using available mutants, we will take biochemical and genetic approaches to identify modified dsRNAs and the mobile RNAs that result from them. We will use new mutants we have isolated that are defective in the intercellular transport of RNAs to discover additional genes that control this process and analyze them. The completion of these aims can reveal how RNAs are modified for export from animal cells and can begin to assemble the pathway for intercellular signaling by the direct transport of RNA between animal cells. These studies are also relevant to understand the entirely unknown biology of extracellular RNAs, which can become powerful diagnostic tools for diseases of internal organs. Finally, if we understand what modifications to dsRNA and other cellular machinery enable the efficient entry of mobile RNAs into C. elegans cells, we can design similar modified dsRNAs for efficient delivery into human cells for RNA interference-based therapy.