Murine Transgenic Models of Prion Diseases

朊病毒病的小鼠转基因模型

• 批准号: 8681545
• 负责人: DAVID A HARRIS
• 金额: $ 46.1万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-15 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8681545
• 关键词: Address; Amino Acids; Animals; Applications Grants; Axon; Biological Process; Blood; Brain; Cell-Free System; Cells; Cessation of life; Charge; Chemicals; Clinical; Cultured Cells; Development; Disease; Familial Creutzfeldt-Jakob Disease; Food Safety; Funding; Genetic; Genetically Engineered Mouse; Glutamate Receptor; Goals; Grant; Human; Infection; Inherited; Ion Channel; Knowledge; Laboratories; Ligands; Link; Liposomes; Mediating; Molecular; Mus; Mutation; N-terminal; Nature; Nerve Degeneration; Neuraxis; Neurodegenerative Disorders; Neurons; Organ; Patch-Clamp Techniques; Pathogenesis; Pathology; Pathway interactions; Phenotype; Play; Point Mutation; PrP; PrP gene; PrPC function; PrPSc Proteins; Prion Diseases; Prions; Property; Protein Region; Proteins; Public Health; Role; Slice; Staging; Symptoms; Synapses; Testing; Therapeutic Effect; Transgenic Mice; Transgenic Model; Work; base; cell injury; early onset; in vitro Assay; inhibitor/antagonist; killings; mouse model; mutant; neuroblastoma cell; neuropathology; neurotoxic; neurotoxicity; novel therapeutic intervention; protein aggregation; protein misfolding; response; wild-type PrP

DESCRIPTION (provided by applicant): The overall goal of this project is to investigate the pathogenesis of prion diseases using transgenic mouse models. Our objective is to understand the molecular and cellular mechanisms by which prions kill neurons and damage the central nervous system. During the last funding period, we investigated how three, distinct genetic mechanisms (loss, gain, and subversion of the normal function of PrPC) contribute to neurodegeneration in two different transgenic models: Tg(PG14) mice, which express an aggregation-prone PrP harboring a nine-octapeptide insertional mutation linked to familial Creutzfeldt-Jakob disease; and Tg(CR) mice, which express a highly neurotoxic form of PrP with a 21-amino acid deletion (residues 105-125) in the conserved, central region of the protein. In the course of our previous work, we made three key discoveries that form the basis for this renewal application. First, we found that mutations in the central region of PrP, including deletions such as CR, as well as point mutations associated with familial prion diseases of humans, induce a powerful ion channel activity that can be observed by patch-clamping techniques. Second, we have identified a group of PrP ligands that inhibit the ion channel activity of mutant PrP. Interestingly, most of these ligands also inhibit the formation of PrPSc, in cell-free systems or mice, suggesting that common structural domains control both the functional activity of PrP and its conversion to PrPSc. Third, we observed that a positively-charged, nine amino acid domain at the N-terminus plays an essential role in the channel-forming and neuroprotective properties of PrP molecules. Taken together, these new findings suggest the hypothesis that the pathogenesis of some inherited prion diseases, and possibly of infectiously acquired cases as well, may be due to PrP-related channel activity. Moreover, these pathogenic effects may be determined by a surprisingly short domain of the PrP primary sequence that controls both ion channel activity and conformational misfolding of the protein. To pursue these observations, we plan to (1) Analyze transgenic models of familial prion diseases associated with a "channel-inducing" PrP mutations; (2) Determine whether PrPSc induces PrPC-dependent, ion channel activation; (3) Test whether inhibitors of PrP-related ion channel activity have therapeutic effect in mouse models of familial and infectious prion diseases; and (4) Investigate the function of the N-terminal polybasic domain of PrP a critical neurotoxicity determinant. This project addresses a major gap in knowledge concerning the mechanisms by which prions are neurotoxic. It explores specific molecular and cellular pathways that may be activated by prions, and that may a role in their pathogenic effects. The proposal ties prion diseases to other neurodegenerative conditions due to abnormal activity of ion channels, and it sets the stage for treating prion diseases by blocking specific neurotoxic pathways in addition to prion propagation.

描述(由申请人提供)：该项目的总体目标是利用转基因小鼠模型研究Pron疾病的发病机制。我们的目标是了解Pron杀死神经元和损害中枢神经系统的分子和细胞机制。在上一个资助期间，我们在两个不同的转基因模型中研究了三种不同的遗传机制(PrPC正常功能的丢失、获得和颠覆)如何导致神经退化：TG(PG14)小鼠表达易于聚集的PrP，其包含与家族性CreutzFeldt-Jakob病相关的九个八肽插入突变；以及TG(CR)小鼠，其表达一种高度神经毒性的PrP形式，在蛋白质的保守的中央区域缺失21个氨基酸(残基105-125)。在我们之前的工作过程中，我们有三个关键发现，这些发现构成了这次续签申请的基础。首先，我们发现PrP中心区的突变，包括CR等缺失，以及与人类家族性Pron疾病相关的点突变，可以诱导强大的离子通道活性，这可以通过膜片钳技术观察到。第二，我们鉴定了一组PrP配体，它们能抑制突变型PrP的离子通道活性。有趣的是，这些配体中的大多数还抑制PrPSc在无细胞系统或小鼠中的形成，这表明共同的结构域控制着PrP的功能活性和它向PrPSc的转化。第三，我们观察到N-末端一个带正电荷的九个氨基酸结构域在PrP分子的通道形成和神经保护特性中起着重要的作用。综上所述，这些新发现提出了一种假设，即一些遗传性PrP疾病以及可能的感染性获得性病例的发病机制可能是由于PrP相关的通道活动。此外，这些致病效应可能是由PrP初级序列的一个令人惊讶的短结构域决定的，该结构域控制着蛋白质的离子通道活性和构象错误折叠。为了进行这些观察，我们计划(1)分析与“通道诱导”PrP突变相关的家族性PrP疾病的转基因模型；(2)确定PrPSc是否可以诱导PrPC依赖的离子通道激活；(3)测试PrP相关离子通道活性的抑制剂是否对家族性和传染性PrP疾病的小鼠模型具有治疗作用；以及(4)研究PrP的N末端多碱域的功能，它是一个关键的神经毒性决定因素。这个项目解决了有关普恩病毒具有神经毒性的机制方面的一个重大知识空白。它探索了可能被普恩激活的特定分子和细胞途径，这可能在它们的致病效应中发挥作用。该提议将普恩病毒疾病与由于离子通道异常活动而导致的其他神经退行性疾病联系在一起，并通过阻断特定的神经毒性途径以及普恩病毒的传播为治疗普恩病毒疾病奠定了基础。