Defining the Role of Cysteinyl-tRNA Synthetase Variants in Neurological Disease

摘要 作为一名内科科学家，我的长期目标是研究神经遗传性疾病的分子机制， 最终目的是开发治疗方法。氨基酰基-tRNA合成酶(Ars)是一种重要的酶。 用同源氨基酸给tRNA充电。到目前为止，37个编码ARS的基因座中有33个发生了突变 与显性周围神经病或隐性多系统疾病有关；然而，等位基因和 ARS相关表型的基因座异质性是不完全的，分子、细胞和生物体 人们对ARS突变的后果知之甚少。半胱氨酰-tRNA合成酶(CARS)编码 在细胞质中用半胱氨酸充电tRNACYS的酶。到目前为止，汽车的变种还没有 与任何人类疾病表型有关。在与NIH未诊断疾病计划的合作下，我们 确诊了来自三个家庭的四名患者，他们患有复杂的综合征，包括小头畸形、发育性 迟缓和轴突周围神经病；每个患者都携带双等位CARS变体。临床和遗传学 有证据支持CARS突变致病性，蛋白质表达研究和酵母菌 互补分析表明，每一种汽车变种都会导致功能丧失效应。而失去的是- 功能分子病理学常见于隐性疾病相关的ARS变异体，下游 对细胞、组织和生物体功能的影响尚不明确。此外，汽车变种在汽车中的作用 显性疾病尚未被发现。研究CARS变异在隐性和显性中的作用 神经疾病，我们将：(1)研究与隐性疾病有关的患者突变对 大脑中的蛋白质翻译；以及(2)在CARS中产生功能丧失的突变，并研究 潜在的显性神经毒性。这项工作将为深入了解CARS的致病机制提供依据 变异，揭示潜在的治疗靶点，并扩大ARS的临床和基因异质性- 相关疾病。重要的是，这个项目将让我发展研究生涯所必需的技能。 重点是了解人类遗传性疾病的机制。

ABSTRACT My long-term goal as a physician-scientist is to study the molecular mechanisms of neurogenetic disorders, with the ultimate aim of developing therapies. Aminoacyl-tRNA synthetases (ARSs) are essential enzymes that charge tRNA with cognate amino acids. To date, mutations in 33 of the 37 ARS-encoding loci have been implicated in dominant peripheral neuropathies or recessive multi-system disorders; however, the allelic and locus heterogeneity of ARS-related phenotypes is incomplete, and the molecular, cellular, and organismal consequences of ARS mutations are poorly understood. Cysteinyl-tRNA synthetase (CARS) encodes the enzyme that charges tRNACYS with cysteine in the cytoplasm. To date, CARS variants have not been implicated in any human disease phenotype. In collaboration with the NIH Undiagnosed Diseases Program, we identified four patients from three families with a complex syndrome that includes microcephaly, developmental delay, and axonal peripheral neuropathy; each patient carries bi-allelic CARS variants. Clinical and genetic evidence are supportive of CARS mutation pathogenicity, and protein expression studies and yeast complementation assays indicate that each CARS variant causes a loss-of-function effect. While a loss-of- function molecular pathology is common to recessive disease-associated ARS variants, the downstream effects on cellular, tissue, and organism function are poorly defined. Additionally, the role of CARS variants in dominant disease has not been explored. To investigate the role of CARS variants in recessive and dominant neurological disease, we will: (1) study the effect of patient mutations implicated in recessive disease on protein translation in the brain; and (2) generate loss-of-function mutations in CARS and investigate the potential for dominant neurotoxicity. This work will provide insight into the pathogenic mechanism of CARS variants, reveal potential therapeutic targets, and expand the clinical and locus heterogeneity of ARS- associated disease. Importantly, this project will allow me to develop the skills necessary for a research career focused on understanding the mechanisms of human inherited disease.