Analyzing how animal prions use existing cellular programs for release and intercellular spread

哺乳动物朊病毒通过正常细胞朊病毒蛋白（PrPc）的模板定向重折叠成病理同种型PrPSc来复制。越来越多的证据表明，这种仅基于蛋白质构象的信息传递的分子过程并不局限于朊病毒疾病。朊病毒样现象已经在各种神经退行性疾病中以及在记忆储存和先天免疫的背景下被描述。目前尚不清楚这些蛋白质聚集体如何在细胞之间转移以及涉及哪些分子和细胞机制。拟议的研究计划将解决这些问题，使用小鼠朊病毒作为模型系统。 我的研究计划的长期目标是更好地了解朊病毒感染的细胞和分子生物学。我们的工作已经确定，朊病毒使用细胞机器进行繁殖，另一方面，它们必须逃避细胞内的降解。我们已经表明，自噬，一个基本的细胞程序的降解和回收，是参与细胞清除和繁殖朊病毒。我们的初步数据表明，自噬，多泡体和朊病毒的释放是相互关联的。这使我们提出了未来五年工作的中心假设，即朊病毒的释放和细胞间扩散受自噬机制和外泌体释放途径之间的相互作用的调节。 目前的研究计划研究的分子和细胞机制参与朊病毒的释放，在其与自噬的相互作用的背景下。将为此进行调查，目的如下： 1.为了分析自噬如何影响细胞培养模型中的外泌体形成和朊病毒释放， 2.研究这种相互作用如何影响感染向受体细胞的传播和细胞向性， 3.在动物模型中研究受损的自噬和外泌体释放如何影响朊病毒感染和朊病毒菌株模式。 我们的研究计划将进一步确定朊病毒在细胞内和细胞间的生命周期，并分析自噬在朊病毒感染中的另一个作用。我们的短期目标可能会对朊病毒的释放和在细胞和组织之间的传播产生新的见解。它们被很好地嵌入到我们的两个总体长期目标中（自噬和朊病毒感染，朊病毒蛋白运输），并被整合到我们的总体目标中，即朊病毒感染的分子生物学特征。

Mammalian prions replicate by template-directed refolding of the normal cellular prion protein (PrPc) into the pathologic isoform PrPSc. There is growing evidence that this molecular process which uses transfer of information based solely upon protein conformations is not restricted to prion diseases. Prion-like phenomena have been described in various neurodegenerative diseases and in the context of memory storage and innate immunity. It is presently not understood how such protein aggregates are transferred between cells and which molecular and cellular machineries are involved. The proposed research program will address these questions, using mouse prions as a model system.     The long-term goal of my research program is to better understand the cellular and molecular biology of prion infections. Our work has established that prions use cellular machineries for propagation, on the other hand they have to escape intracellular degradation. We have shown that autophagy, a basic cellular program for degradation and recycling, is involved in cellular clearance and propagation of prions. Our preliminary data suggest that autophagy, multi-vesicular bodies and prion release are interconnected. This leads us to propose as central hypothesis for the work over the next five years that release and intercellular spread of prions are regulated by the interplay between the autophagy machinery and exosomal release pathways.     The current research program studies the molecular and cellular mechanisms involved in prion release, in the context of its interplay with autophagy. This will be investigated in the following aims: 1. to analyze how autophagy affects exosome formation and prion release in cell culture models, 2. to examine how this interplay impacts spread of infection to recipient cells and cell tropism, and 3. to study in animal models how compromised autophagy and exosomal release impact prion infection and prion strain modalities.     Our research program will further define the life cycle of prions in and between cells and analyse another role of autophagy in prion infection. Our short-term goals are likely to produce new insights into prion release and spread between cells and tissues. They are nicely embedded into two of our overall long-term goals (autophagy and prion infections, prion protein trafficking) and are integrated into our overarching goal which is to characterize the molecular biology of prion infections.