Murine Transgenic Models of Prion Diseases

描述(由申请人提供)：本申请的总体目标是使用转基因(TG)小鼠模型来研究Pron疾病的发病机制。我们的目标是了解Pron杀死神经元和损伤中枢神经系统的分子和细胞机制。我们工作的一个主要焦点是表达带有九个八肽插入突变(PG14)的PrP分子的TG小鼠，该突变与人类克雅病的家族性形式有关。这些小鼠建立了遗传性人类PrP疾病的几个基本特征，包括进行性共济失调、神经元丢失、星形细胞增多和异常折叠形式的突变PrP的积累。在之前的资助期间，我们创建了新的TG小鼠品系，它们在四环素调控的启动子的控制下，在前脑神经元中选择性地表达PG14 PrP；我们研究了ER相关的降解是否在突变蛋白的代谢中发挥了作用；我们比较了两种形式的PG14 PrP的分子和生物学特性，它们在感染性和寡聚体结构上存在显著差异。在目前的应用中，我们建议扩大我们对PrP相关致病过程的搜索。在每个目标中，我们将探索PrP可能产生神经毒性效应的三种互补机制之一：功能获得、功能丧失和功能颠覆。在第一个目标中，我们将使用表达GFP标记版本的PG14 PrP的TG小鼠来探索PG14 PrP聚集体干扰轴突运输和突触功能的假设，以及这种毒性活动与TG(PG14)小鼠的疾病表型有关。在第二个目标中，我们将确定PrP正常神经保护活性的丧失是否会导致TG(PG14)小鼠的神经变性。在第三个目标中，我们将研究PrP的一种缺失形式的神经毒性效应，该形式可能通过颠覆PrP的正常功能来发挥作用，就像PrPSc被认为在PrP感染期间所做的那样。我们预计，这些研究将为蛋白诱导的神经退行性变过程提供洞察力，并将确定这些和其他神经退行性疾病治疗干预的分子靶点。

DESCRIPTION (provided by applicant): The overall goal of this application is to investigate the pathogenesis of prion diseases using transgenic (Tg) mouse models. Our objective is to understand the molecular and cellular mechanisms by which prions kill neurons and damage the CNS. A major focus of our work has been on Tg mice that express a PrP molecule with a nine-octapeptide insertional mutation (PG14) associated with a familial form of Creutzfeldt- Jakob disease in humans. These mice model several essential features of inherited human prion diseases, including progressive ataxia, neuronal loss, astrocytosis, and accumulation of an abnormally folded form of mutant PrP. During the previous funding period, we created new lines of Tg mice which selectively express PG14 PrP in forebrain neurons under control of a tetracycline-regulated promoter; we investigated whether ER-associated degradation plays a role in the metabolism of the mutant protein; and we compared the molecular and biological properties of two forms of PG14 PrP that differ dramatically in their infectivity and oligomeric structure. In the present application, we propose to expand our search for PrP-related pathogenic processes. In each of the aims, we will explore one of three complementary mechanisms by which PrP might produce neurotoxic effects: gain of function, loss of function, and subversion of function. In the first aim, we will use Tg mice expressing a GFP-tagged version of PG14 PrP to explore the hypothesis that aggregates of PG14 PrP interfere with axonal transport and synaptic function, and that this toxic activity contributes to the disease phenotype in Tg(PG14) mice. In the second aim, we will determine whether loss of a normal neuroprotective activity of PrP contributes to neurodegeneration in Tg(PG14) mice. In the third aim, we will investigate the neurotoxic effects of a deleted form of PrP that may act by subverting the normal function of PrP, much like PrPSc is thought to do during prion infection. We anticipate that these studies will provide insights into the process of prion-induced neurodegeneration, and will identify molecular targets for therapeutic intervention in these and other neurodegenerative disorders.