ION CHANNEL MODULATION BY THE PRION PROTEIN: A NOVEL TOXIC MECHANISM

朊病毒蛋白对离子通道的调节：一种新的毒性机制

• 批准号: 8094244
• 负责人: DAVID A HARRIS
• 金额: $ 35.4万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8094244
• 关键词: Agonist; Amino Acids; Aminoglycoside Antibiotics; Animal Model; Animals; Applications Grants; Attention; Biochemical; Biological; Biological Assay; Birth; Bleomycin; Blood; Brain; Calcium; Cell Culture Techniques; Cell Death; Cell surface; Cells; Cessation of life; Chemicals; Clinical; Creutzfeldt-Jakob Syndrome; Cultured Cells; Data; Deletion Mutation; Dependence; Development; Disease; Dose; Drug Hypersensitivity; Exhibits; Food Safety; Gerstmann-Straussler-Scheinker Disease; Glutamate Receptor; Glutamates; Human; Infectious Agent; Inherited; Ion Channel; Kinetics; Laboratories; Learning; Link; Longevity; Measures; Mediating; Mediator of activation protein; Membrane Glycoproteins; Molecular; Mus; Mutation; Nature; Nerve Degeneration; Nervous system structure; Neurodegenerative Disorders; Neurons; Neurotransmitters; Normal Cell; Nucleic Acids; Organ; Pathogenesis; Pathology; Pathway interactions; Peptide Hydrolases; Pharmaceutical Preparations; Phenotype; Physiological; Play; Point Mutation; Positioning Attribute; PrPC function; PrPSc Proteins; Prion Diseases; Prions; Process; Proliferating; Property; Protein Isoforms; Protein Region; Proteins; Public Health; Recombinants; Resistance; Role; Scrapie; Signal Pathway; Signal Transduction; Surveys; Techniques; Testing; Therapeutic; Therapeutic Intervention; Time; Toxic effect; Transducers; Transgenic Mice; Voltage-Clamp Technics; base; cell type; cytotoxicity; experimental analysis; gain of function mutation; human disease; in vitro Assay; in vitro activity; inhibitor/antagonist; insight; interest; killings; mouse model; mutant; neoplastic; neurodegenerative phenotype; neuropathology; neurotoxic; neurotoxicity; novel; public health relevance; research study; response; tool; voltage

DESCRIPTION (provided by applicant): A great deal is now known about the chemical nature of prions and the mechanism by which they propagate. In contrast, how abnormal forms of the prion protein (PrP) kill nerve cells is still a mystery. There is evidence that the neurotoxicity of prions lies in their ability to alter or subvert a normal, physiological function of PrPC, the cellular form of PrP, but the details of this process are obscure. Tg(?CR) mice, which express a mutant PrP deleted for residues 105-125, provide powerful insights into prion related pathogenic mechanisms. These animals spontaneously develop a severe neurodegenerative illness that is reversed in a dose-dependent fashion by co-expression of wild-type PrP. We have been interested in elucidating the cellular and molecular mechanisms underlying the powerful toxicity of PrP?CR. We have recently discovered that the ?CR deletion acts as a dominant, gain-of-function mutation that strongly activates an ion channel activity that is intrinsic to, or is indirectly induced by, PrP. Moreover, we have found that disease-associated point mutations in the central region of PrP have a similar effect, suggesting that some familial prion diseases are due to excitotoxic activation of ion channels. In this application, we propose to critically test an "ion channel hypothesis" of prion diseases. First, we will survey all known human mutations in the central region of PrP for their effect on ion channel activity in vitro. We will then undertake characterization of the biophysical properties of the channels induced by PrP molecules carrying point and deletion mutations in the central region. Finally, we will determine if excitotoxic activation of ionotropic glutamate receptors plays a role in the neuronal death and neuropathology induced by mutant PrP molecules and infectious PrPSc. The pathogenic mechanisms elucidated in this project are likely to have wide applicability, since abnormal activation of ion channels is a well established paradigm in a number of other neurodegenerative diseases and animal models. Moreover, identification of specific ion channel targets for PrP-mediated toxicity would represent the first step in development of an entirely new class of anti-prion drugs that inhibit cellular neurotoxic pathways, rather than PrPSc propagation. PUBLIC HEALTH RELEVANCE: Prion diseases are fatal neurodegenerative disorders of humans and animals that pose a grave threat to public health, and endanger the safety of the food, blood and organ supplies. This application will explore a novel mechanism of prion pathogenesis based on abnormalities in the ion channels that control electrical activity in the nervous system. This project represents the first step in development of an entirely new class of anti-prion drugs that inhibit cellular neurotoxic pathways, rather than prion propagation.

描述(由申请者提供)：现在人们已经知道了许多关于Pron的化学性质和它们的繁殖机制。相比之下，PrP的异常形式如何杀死神经细胞仍然是一个谜。有证据表明，PrP的神经毒性在于它们能够改变或颠覆PrPC的正常生理功能，PrPC是PrP的细胞形式，但这一过程的细节尚不清楚。Tg(？cr)小鼠表达缺失残基105-125的突变型PrP，为深入研究PrP相关的致病机制提供了有力的线索。这些动物自发地发展出一种严重的神经退行性疾病，通过野生型PrP的共同表达以剂量依赖的方式逆转。我们一直有兴趣阐明PrP？cr强大毒性的细胞和分子机制。我们最近发现，？cR缺失是一种显性的功能获得突变，它强烈激活PrP固有的或间接诱导的离子通道活性。此外，我们还发现PrP中心区与疾病相关的点突变也有类似的作用，这表明一些家族性PrP疾病是由于离子通道的兴奋性毒性激活所致。在这一应用中，我们建议批判性地检验普恩病毒疾病的“离子通道假说”。首先，我们将调查所有已知的人类PrP中心区突变对体外离子通道活性的影响。然后，我们将对中心区域携带点突变和缺失突变的PrP分子诱导的通道的生物物理性质进行表征。最后，我们将确定离子型谷氨酸受体的兴奋性毒性激活是否在突变PrP分子和感染性PrPSc诱导的神经元死亡和神经病理中发挥作用。本项目阐明的致病机制可能具有广泛的适用性，因为离子通道的异常激活在许多其他神经退行性疾病和动物模型中是一个公认的范例。此外，识别PrP介导的毒性的特定离子通道靶标将是开发一类全新的抗PrP药物的第一步，这种药物可以抑制细胞神经毒性途径，而不是PrPSc的传播。 与公共卫生相关：Prion病是人类和动物的致命神经退行性疾病，对公共健康构成严重威胁，并危及食品、血液和器官供应的安全。这一应用将探索一种基于控制神经系统电活动的离子通道异常的Prion发病机制。该项目代表了开发一种全新的抗普鲁恩药物的第一步，这种药物可以抑制细胞神经毒性途径，而不是普恩传播。