Mechanisms of Toxicity in C. elegans Models of Transthyretin Amyloidosis

线虫运甲状腺素蛋白淀粉样变模型的毒性机制

• 批准号: 9480905
• 负责人: SANDRA E Encalada
• 金额: $ 11.81万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9480905
• 关键词: Affect; Age; Aging; Alpha Cell; Amyloidosis; Animal Model; Antibodies; Autonomic nervous system; Axonal Transport; Biochemical; Biochemistry; Biological; Blood; Caenorhabditis elegans; Cardiomyopathies; Cardiovascular Diagnostic Techniques; Cells; Cellular biology; Complement; Cytoskeleton; Data; Defect; Degenerative Disorder; Development; Disease; Dissociation; Drosophila genus; Elderly; Exhibits; Familial Amyloid Neuropathies; Functional disorder; Genetic; Genetic Screening; Heart; Homeostasis; Human; Image; Impairment; Individual; Link; Liver; Locomotion; Longevity; Maps; Measures; Messenger RNA; Microtubules; Mitochondria; Mitotic; Modeling; Molecular; Molecular Conformation; Molecular Motors; Molecular Target; Morphology; Mus; Muscle; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Neuroglia; Neurons; Neuropathy; Organism; Pathology; Pathway interactions; Patients; Peripheral; Peripheral Nervous System Diseases; Pharmaceutical Preparations; Phenotype; Physiological; Prealbumin; Process; Proteins; RNA Interference; Reporting; Structure; Synapses; Testing; Therapeutic; Time; Tissues; Toxic effect; Transgenic Organisms; age related; amyloidogenesis; autonomic neuropathy; base; cytotoxicity; experimental study; extracellular; forward genetics; genome sequencing; human disease; improved; in vivo; monomer; novel; novel therapeutic intervention; novel therapeutics; protein aggregation; proteotoxicity; public health relevance; small molecule; tool; trafficking; whole genome

 DESCRIPTION (provided by applicant): Protein aggregation is a feature of most neurodegenerative diseases, including the transthyretin (TTR) amyloidoses. TTR is a tetrameric protein secreted into the blood by the liver. Compelling evidence suggests that peripheral neurodegeneration in the TTR amyloidoses results from rate- limiting TTR tetramer dissociation, aberrant monomer misfolding and misfolded TTR assembly into a spectrum of TTR aggregate structures. Extracellular aggregation leads to proteotoxicity in tissues not synthesizing TTR by a cell non-autonomous process that we seek to understand via the proposed experiments, and which is not understood for any aggregation-associated neurodegenerative disease. In humans, WT TTR aggregation leads to a cardiomyopathy, whereas aggregation of other TTR mutations leads to a primary neuropathy. Herein, we report the development and partial characterization of transgenic Caenorhabditis elegans models of the TTR amyloidoses, exhibiting TTR aggregation and three cell non-autonomous quantifiable neuronal TTR proteotoxicity-associated cellular and sub-cellular phenotypes with direct relevance to human disease. We will characterize TTR mRNA levels and TTR conformations including tetramers, and misfolded TTR oligomers in these models as a function of aging and correlate these with the neuronal phenotypes observed. Defects in microtubule-based trafficking appear to be a centrally important mechanistic feature of TTR proteotoxicity. The availability of novel small molecule and genetic tools to quantify TTR conformation, as well as the ability to image sub-cellular phenotypes in a single neuron as a function of aging in the same living worm to quantify phenotypic changes affords us an extraordinary opportunity to understand the cell biology and biochemistry of neurodegeneration. Access to the drug tafamidis, which dramatically slows progression of the TTR amyloidoses in humans will also allow us to discern how inhibition of TTR aggregation alters the cell biological and biochemical defects apparently underlying neurodegeneration in these models. To further understand the mechanisms of TTR proteotoxicity at the cellular and molecular level, we will search for modulators of TTR proteotoxicity by identifying suppressors of a locomotion defect exhibited by one of our TTR models in a unbiased forward genetic screen. We have identified candidate suppressors in a pilot screen and showed that some exhibited proper TTR synthesis and secretion, suggesting that this screen could identify tissue specific molecular targets that are relays between the formation of extracellular TTR aggregates and cellular toxicity. These studies will establish TTR C. elegans models as relevant to the study of cell non-autonomous TTR toxicity.

 描述（由适用提供）：蛋白质聚集是大多数神经退行性疾病的特征，包括甲状腺素蛋白（TTR）淀粉样蛋白。 TTR是肝脏分泌到血液中的四聚体蛋白。令人信服的证据表明，TTR淀粉样蛋白的周围神经退行性因素是由于限制TTR四聚体解离，异常单体错误折叠和错误折叠的TTR组装而导致的，将TTR组装成一系列TTR聚集体结构。细胞外聚集会导致组织的蛋白质毒性，而不是通过提出的实验来理解的细胞非自主过程，而不是通过拟议的实验理解的，并且对于任何与聚集相关的神经退行性疾病都不理解。在人类中，WT TTR聚集会导致心肌病，而其他TTR突变的聚集会导致原发性神经病。在此，我们报告了TTR淀粉样蛋白的转基因Caenorhabditis模型的发育和部分表征，进行TTR聚集和三个细胞非自主可量化的可量化神经元TTR蛋白毒性蛋白毒性相关的细胞和下细胞表型与与人类病的直接相关。我们将表征包括四聚体在内的TTR mRNA水平和TTR构象，以及在这些模型中错误折叠的TTR低聚物作为衰老的函数，并将其与观察到的神经元表型相关联。基于微管的运输外观的缺陷是TTR蛋白毒性的中央重要机械特征。新型的小分子和遗传工具量化TTR构象的可用性，以及单个神经元中的亚细胞表型的能力作为在同一活蠕虫中衰老以量化表型变化的函数，这使我们有一个非凡的机会，可以理解细胞生物学和神经化学生物的生物学。进入人类中TTR淀粉样蛋白的进展大大减缓的药物tafamidis也将使我们能够辨别TTR聚集的抑制如何改变细胞生物学和生化缺陷，显然是这些模型中神经变性的潜在。为了进一步了解细胞和分子水平上TTR蛋白毒性的机制，我们将通过在公正的前向遗传筛选中识别一个由TTR模型暴露的机车缺陷的补充来搜索TTR蛋白毒性的调节剂。我们已经在试点屏幕中确定了候选补充剂，并表明一些暴露的适当的TTR合成和分泌，表明该筛选可以鉴定组织特定的分子靶标，这些分子靶标是细胞外TTR骨料和细胞毒性之间的中继。这些研究将建立与细胞非自主TTR毒性的研究有关的TTR C.秀丽隐杆线模型。