Mechanisms of prion strain dynamics

朊病毒应变动力学机制

基本信息

批准号：
10450690
负责人：
Jason C Bartz
金额：
$ 37.06万
依托单位：
CREIGHTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-30 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10450690
关键词：
Alzheimer&apos s Disease Animals Biochemical Biological Cell Culture Techniques Cells Clinical Cloning Disease Disease Outcome Ecology Environment Equipment Goals Human In Vitro Individual Investigation Measures Minor Molecular Conformation Nerve Degeneration Neurodegenerative Disorders Parkinson Disease Pathogenicity Pharmaceutical Preparations Pharmacotherapy Population Positioning Attribute PrP PrPC Proteins PrPSc Proteins Prion Diseases Prions Property Proteins Reaction Resistance Route Seeds Series Structure Technology Testing Virulence Work Zoonoses base cross-species transmission experimental study fitness in vivo neuropathology pressure prion hypothesis protein misfolding response tissue tropism transmission process

Alzheimer&apos s Disease Animals Biochemical Biological Cell Culture Techniques Cells Clinical Cloning Disease Disease Outcome Ecology Environment Equipment Goals Human In Vitro Individual Investigation Measures Minor Molecular Conformation Nerve Degeneration Neurodegenerative Disorders Parkinson Disease Pathogenicity Pharmaceutical Preparations Pharmacotherapy Population Positioning Attribute PrP PrPC Proteins PrPSc Proteins Prion Diseases Prions Property Proteins Reaction Resistance Route Seeds Series Structure Technology Testing Virulence Work Zoonoses base cross-species transmission experimental study fitness in vivo neuropathology pressure prion hypothesis protein misfolding response tissue tropism transmission process

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项目摘要

Prion diseases are inevitably fatal neurodegenerative zoonotic disorders of animals, including humans, with no known treatment or cure. Prions are comprised largely, if not entirely, of PrPSc, a misfolded form of the normal non-infectious prion protein PrPC. Prion strains are operationally defined by differences in neuropathology that breed true under controlled conditions that are encoded by strain-specific conformations of PrPSc. The long- term goal of this work is to understand the dynamics of prion strains. The objective of this application is to determine if prion strains exist as a mixture of substrains or as a homogeneous population. We hypothesize that prions strains are a dynamic mixture of prion substrains (i.e. quasispecies). This would fundamentally impact our understanding of the mechanism of interspecies transmission, adaptation of prions in response to anti-prion drugs, the ecology of prion transmission in natural settings and may be relevant to other protein misfolding diseases that share prion strain-like features (e.g. Alzheimer’s). Since the structure of PrPSc is poorly defined and technologies do not exist to measure the structure of an individual protein in a mixture, we will test the hypothesis based on the predicted properties of quasispecies that are experimentally feasible. First we will determine the effect of repeated limiting dilutions on prion fitness. Repeated bottleneck passage of a quasispecies leads to a reduction in fitness (i.e. Muller’s ratchet) since, on average, the fitness of an individual infectious unit is lower compared to the fitness of the overall population. We anticipate that repeated transmission of prions at limiting dilutions in PMCA or in cell culture will result in a reduction in the fitness of the prion agent compared to agent passaged at high titer. Second we will establish if biologically cloned prion strains contain substrains. Quasispecies hypothesis predicts that any given prion strain is comprised of a dynamic population of substrains. We will test this by amplifying PrPSc in vitro or passaging in cells under conditions that favor the selection of a minor substrain. In a second series of experiments, we will select for subpopulations of PrPSc that have common shared biochemical features to seed PMCA reactions or prion susceptible RK13 cells. Serial repeated rounds of selection followed by transmission in animals will determine if biologically cloned prion strains contain additional strains and if biochemical selective pressure results in the emergence of strains with the selected properties. The results of these experiments will directly test the hypothesis that prions are quasispecies.

病毒疾病不可避免地是包括人类在内的动物的致命神经退行性疾病，没有已知的治疗或治愈。 prions在很大程度上包括PRPSC的（即使不是完全），这是一种错误的形式非感染prion蛋白PRPC。 prion菌株在操作上是由神经病理学的差异所定义的在受控条件下由PRPSC的特定构象编码的受控条件。长期这项工作的术语目标是了解prion菌菌株的动态。该应用的目的是确定prion菌株是否作为基质的混合物或同质种群存在。我们假设王室菌株是prion基底物的动态混合物（即quasisspecies）。这将是从根本上讲影响我们对种间传播机制的理解，适应王室的反应抗植物药物，自然环境中的prion传播的生态学，可能与其他蛋白质有关具有类似prion菌株的特征（例如阿尔茨海默氏症）的错误折叠疾病。由于PRPSC的结构是定义较差，并且不存在用于测量混合物中单个蛋白质的结构的技术，我们将根据实验可行的准菜的预测特性来检验假设。第一的我们将确定重复限制稀释液对主要健身的影响。重复的瓶颈通道准特性会导致健身降低（即Muller的棘轮），因为平均而言与整体人口的适应性相比，传染性单位较低。我们预计重复在PMCA或细胞培养中限制稀释稀释度的王室的传播将导致适应性降低与高滴度传递的代理相比，prion剂。第二，我们将确定生物克隆的prion是否菌株包含基质。 quasisspecies假设预测，任何给定的prion菌株均已完成基质的动态种群。我们将通过在体外扩增PRPSC或在细胞下进行测试有利于选择次要基质的条件。在第二个实验中，我们将选择具有共同共享生化特征的PRPSC的亚群易感RK13细胞。串行重复的选择，然后在动物中传播，将确定如果生物克隆的pr菌株含有其他菌株，并且生化选择性压力导致所选特性的菌株的出现。这些实验的结果将直接测试假设王室是准人。