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）小鼠模型研究朊病毒疾病的发病机制。我们的目标是了解朊病毒杀死神经元和损害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Tg小鼠，其表达具有与人类家族性克雅氏病相关的九肽插入突变（PG 14）的PrP分子。这些小鼠模拟了遗传性人类朊病毒疾病的几个基本特征，包括进行性共济失调、神经元丢失、星形细胞增多和突变型PrP异常折叠形式的积累。在前一个资助期内，我们创造了新的Tg小鼠系，它们在四环素调节启动子的控制下在前脑神经元中选择性表达PG 14 PrP;我们研究了ER相关降解是否在突变蛋白的代谢中发挥作用;我们比较了两种形式的PG 14 PrP的分子和生物学特性，它们的感染性和寡聚体结构存在显着差异。在本申请中，我们建议扩大我们对PrP相关致病过程的搜索。在每一个目标，我们将探讨三个互补的机制之一，PrP可能产生神经毒性作用：功能的获得，功能的丧失和功能的颠覆。在第一个目标中，我们将使用表达GFP标记的PG 14 PrP版本的Tg小鼠来探索PG 14 PrP聚集体干扰轴突运输和突触功能的假设，并且这种毒性活性有助于Tg（PG 14）小鼠的疾病表型。在第二个目标中，我们将确定是否损失的正常神经保护活性的PrP有助于神经退行性病变的Tg（PG 14）小鼠。在第三个目标中，我们将研究PrP缺失形式的神经毒性作用，该缺失形式可能通过破坏PrP的正常功能来起作用，就像PrPSc被认为在朊病毒感染期间所做的那样。我们预计，这些研究将提供深入了解朊病毒诱导的神经退行性疾病的过程，并将确定这些和其他神经退行性疾病的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.