Degenerative and Dementing Diseases of Aging

描述（由申请人提供）：在包括四个科学项目和四个核心的本申请中，我们建议继续我们的研究，重点是由人类朊病毒疾病引起的神经变性，其中最常见的是散发性（S）CJD。朊病毒似乎只由PrPSc分子组成，而PrPSc分子是通过一个知之甚少的过程从前体PrPc衍生而来的。这里描述的研究旨在定义PrPSc的结构，表征小分子与PrPc和PrPSc的相互作用，并解剖不同人类朊病毒株繁殖的分子事件。在项目1中，我们建议研究聚氧乙烯酸酯（POM）与PrPSc的相互作用。POM磷钨酸盐阴离子[PW 12 O 40]（PTA）与PrPSc特异性结合，但不与PrP结合。POM是一类具有刚性多面体结构的无机金属氧化物簇，其在尺寸、形状和电荷密度上显示出显著变化。在项目2中，我们建议对导致遗传性朊病毒病的55个残基的MoPrP（89-143，P101 L）肽、已知形成淀粉样原纤维的20 mer wt PrP（106-126）肽以及纯化的截短（PrP 27-30）和全长PrPSc进行纤维衍射研究，这两种肽在野生型动物中均具有感染性。在项目3中，我们建议研究引起sCJD的朊病毒。这些研究是可能的，因为我们最敏感的Tg小鼠品系表达嵌合人/小鼠PrP在接种sCJD朊病毒后约80天内死亡。在这些Tg小鼠中进行的人类朊病毒的相对快速的生物测定使得测量整个脑以及从死亡的sCJD患者收集的外周器官和体液中的朊病毒滴度变得实用。我们还建议建立sCJD和变异型（v）CJD的豚鼠模型。在项目4中，我们建议发现新的配体，结合并稳定人PrPc。我们还计划确定这些配体是否抑制HuPrPc转化为HuPrPSc。使用虚拟筛选方法，大型有机分子库将与HuPrPc的已知结构对接。将测试高分化合物的生物药理学结合，控制抗淀粉样蛋白抑制剂倾向于的非特异性抑制。所有拟议研究的最终目标是确定人类朊病毒形成的分子事件，以开发治疗人类朊病毒疾病的疗法。

DESCRIPTION (provided by applicant): In this application comprising four scientific projects and four-cores, we propose to continue our studies focused on neurodegeneration caused by human prion diseases, the most common of which is sporadic (s) CJD. Prions seem to be composed solely of PrPSc molecules, which are derived from a precursor PrPc by a poorly understood process. The studies described here are aimed at defining the structure of PrPSc, characterizing the interactions of small molecules with both PrPc and PrPSc and dissecting the molecular events governing the propagation of different human prion strains. In Project 1, we propose to study the interactions of polyoxometalates (POMs) with PrPSc. The POM phosphotungstate anion [PW12O40] (PTA) binds specifically to PrPSc, but not to PrP. POMs are a large class of inorganic metal oxide clusters with rigid polyhedral structures displaying substantial variations in size, shape, and charge density. In Project 2, we propose to carry out fiber diffraction studies of the 55-residue MoPrP(89-143,P101L) peptide that causes inherited prion disease, a 20 mer wt PrP(106-126) peptide known to form amyloid fibrils as well as purified truncated (PrP 27-30) and full-length PrPSc, both of which are infectious in wild-type animals. In Project 3, we propose to study the prions causing sCJD. These studies are possible because our most sensitive Tg mouse line expressing chimeric human/mouse PrP succumbs to disease in ~80 days after inoculation with sCJD prions. Relatively rapid bioassays of human prions in these Tg mice make it practical to measure the titers of prions throughout brain as well as in peripheral organs and body fluids collected from dead sCJD patients. We also propose to develop guinea pig models of sCJD and variant (v) CJD. In Project 4, we propose to discover new ligands that bind to and stabilize human PrPc. We also plan to determine whether such ligands inhibit the conversion of HuPrPc into HuPrPSc. Using a virtual screening approach, large libraries of organic molecules will be docked against the known structure of HuPrPc. High-scoring compounds will be tested for binding biophysically, controlling for non-specific inhibition to which anti-amyloid inhibitors are prone. The ultimate goal of all the proposed studies is to define the molecular events that feature in the formation of human prions in order to develop therapeutics that cure the human prion diseases.