Mechanisms of prion spread

描述（由申请人提供）：朊病毒疾病是由朊病毒蛋白聚合形式PrPSc引起的致命神经退行性疾病。朊病毒是唯一一种作为传染病自然传播的蛋白质聚集体，最近，人与人之间的传播可能通过输入受朊病毒污染的血液发生。大多数自然传播病例通过外周接触发生，随后朊病毒扩散到中枢神经系统。虽然朊病毒被认为是通过周围神经传播到中枢神经系统，但其神经传递的分子机制尚不清楚。因此，这项拨款申请的一个主要目标是了解朊病毒如何聚集扩散到中枢神经系统。我们假设朊病毒通过逆行轴突运输传播，并将使用体外和体内实验模型来解决这一假设。为实现这一目标，提出了三个目标。在第一个目标中，我们将使用在轴突终末和细胞体之间有液体分离的区隔神经元培养物来测试PrPSc轴突运输的机制。我们还将在体内评估朊病毒株的周围神经转运。在第二个目标中，我们将测量容易传播到中枢神经系统的高毒性朊病毒株的结构特性。在第三个目标中，我们将利用转基因小鼠和表达具有或缺乏GPI锚点的PrPC的原代神经元，确定PrPC的GPI膜锚点在朊病毒传播到大脑中的作用。我们期望这些研究将提供关于朊病毒传播基本机制的关键缺失信息，这将对开发免疫疗法和预防或阻止疾病进展的新治疗策略至关重要。

DESCRIPTION (provided by applicant): Prion diseases are fatal neurodegenerative disorders caused by an aggregated form of the prion protein, PrPSc. Prions are the only protein aggregates that are naturally transmitted as an infectious disease, and most recently, human to human transmission likely occurred by transfusion of prion-contaminated blood. Most cases of natural transmission occur through a peripheral exposure followed by prion spread to the CNS. Although prions are thought to spread via peripheral nerves to the CNS, the molecular mechanisms underlying neuronal transit are unclear. For this reason, a major goal of this grant application is to understand how prion aggregates spread to the CNS. We hypothesize that prions propagate by retrograde axonal transport and will address this hypothesis using in vitro and in vivo experimental models. To accomplish this goal, three aims are proposed. In the first aim, we will test the mechanism of PrPSc axonal transport using compartmentalized neuronal cultures that have a liquid separation between the axon terminals and the cell bodies. We will additionally assess the peripheral nerve transport of prion strains in vivo. In the second aim, we will measure the structural properties of the highly virulent prion strains that readily spread to he CNS. In the third aim, we will determine the role of the GPI membrane anchor of PrPC on prion spread to the brain using transgenic mice and primary neurons that express PrPC possessing or lacking the GPI anchor. We expect that these studies will provide critical missing information on the basic mechanisms of prion spread that will be essential for the development of immunotherapies and novel therapeutic strategies to prevent or arrest disease progression.