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: 8539088
• 负责人: DAVID A HARRIS
• 金额: $ 33.86万
• 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/8539088
• 关键词: Agonist; Amino Acids; Aminoglycoside Antibiotics; Animal Model; Animals; 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.

描述（由申请人提供）：关于朊病毒的化学性质及其传播机制，现在已经知道了很多。相比之下，异常形式的朊病毒蛋白（PrP）如何杀死神经细胞仍然是一个谜。有证据表明朊病毒的神经毒性在于它们能够改变或破坏PrPC（PrP的细胞形式）的正常生理功能，但这一过程的细节尚不清楚。Tg（？CR）小鼠，其表达缺失残基105-125的突变PrP，提供了对朊病毒相关致病机制的有力见解。这些动物自发地发展严重的神经退行性疾病，其通过野生型PrP的共表达以剂量依赖性方式逆转。我们一直有兴趣阐明潜在的强大的毒性PrP的细胞和分子机制？CR.我们最近发现，？CR缺失作为一种显性的功能获得性突变，可强烈激活PrP固有或间接诱导的离子通道活性。此外，我们发现PrP中心区域的疾病相关点突变具有类似的效果，这表明一些家族性朊病毒疾病是由于离子通道的兴奋毒性激活。在本申请中，我们建议严格检验朊病毒疾病的“离子通道假说”。首先，我们将调查所有已知的人类突变的中心区域的PrP离子通道活性在体外的影响。然后，我们将进行表征的生物物理特性的通道引起的PrP分子携带点和缺失突变的中心区域。最后，我们将确定离子型谷氨酸受体的兴奋毒性激活是否在突变型PrP分子和感染性PrPSc诱导的神经元死亡和神经病理学中发挥作用。本项目中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，识别特定的离子通道目标PrP介导的毒性将代表开发一个全新的类抗朊病毒药物，抑制细胞神经毒性途径，而不是PrPSc传播的第一步。