Spinal Muscular Atrophy: Cell-based drug screens for treatment of axonal defects

脊髓性肌萎缩症：用于治疗轴突缺陷的细胞药物筛选

基本信息

批准号：
8049704
负责人：
Wilfried Rossoll
金额：
$ 19.38万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-04-01 至 2014-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8049704
关键词：
Actins Address Affect Animal Model Anterior Axon Axonal Transport Biological Assay Cause of Death Cell Culture Techniques Cell Line Cells Cellular Assay Clinical Trials Complex Cytoplasmic Granules Defect Development Disease Effectiveness Engineering Fluorescence Functional disorder Funding Future Genes Genetic Goals Growth Cones Horns Human Incidence Infant Infant Mortality Lead Messenger RNA Microfilaments Molecular Motor Neurons Muscle Weakness Muscular Atrophy Mutation Natural regeneration Nerve Degeneration Neurodegenerative Disorders Neuromuscular Diseases Neurons Newborn Infant Pathway interactions Patients Pharmaceutical Preparations Pluripotent Stem Cells Preclinical Drug Evaluation Protein Deficiency Proteins RNA Splicing RNA Transport Reporter Role SMN protein (spinal muscular atrophy)Screening procedure Series Spinal Cord Spinal Muscular Atrophy Stem cells Synapses Testing Therapeutic Translating Translational Research Translations United States National Institutes of Health actin 2 axon growth base cell type cofactor drug candidate effective therapy embryonic stem cell high throughput screening human disease innovation motor neuron degeneration mouse model neuron loss novel novel strategies public health relevance research study

项目摘要

DESCRIPTION (provided by applicant): Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality. SMA is an autosomal recessive neuromuscular disorder characterized by degeneration of the anterior horn motor neurons in the spinal cord, leading to symmetrical muscle weakness and atrophy. It is caused by mutations or deletions in the gene encoding the survival motor neuron protein (SMN), a ubiquitous protein involved in mRNA splicing. It is still unknown why motor neurons are so specifically vulnerable to low levels of SMN and how SMN deficiency selectively causes motor neuron cell death. Currently there is no cure or treatment available to stop its progression. We and others have shown that low levels of SMN lead to axonal growth defects, impaired 2-actin mRNA transport and reduced 2-actin protein levels in growth cones of motor neurons. These findings represent the first known molecular defect in SMN-deficient neurons and suggest an axon-specific function for SMN. We hypothesizes that SMN may act as an important cofactor for the assembly, transport and/or local translation of 2-actin mRNA granules in axonal growth cones. Defects in axonal mRNA localization and translation of 2-actin may contribute to the axonal dysfunction and neurodegeneration typical of SMA. Previous efforts to develop treatments for SMA did not directly target axonal defects in SMN-deficient motor neurons. In this translational research application for funding to the NIH, we propose to perform cell-based high throughput screens for drugs that correct functional deficits in SMN-deficient motor neurons. Firstly, we will use pluripotent stem cell-derived motor neurons to identify drugs that enhance transport of 2-actin mRNA into axonal growth cones. Secondly, we will screen for drugs that raise 2-actin protein levels in growth cones. Novel drug candidates identified in these screens will be validated for effectiveness through a progressive series of tests in cultured primary motor neurons and SMA mouse models. Given the human toll of this disease and the lack of an effective therapy, it is our goal to translate recent progress in understanding the function of SMN in motor neurons into the development of effective drugs for the treatment of SMA. PUBLIC HEALTH RELEVANCE: We propose to use stem cell-derived motor neurons to screen for drugs for the treatment of axonal defects in spinal muscular atrophy. Molecules that raise 2-actin mRNA and protein levels in axons and growth cones have the potential to be used as drugs for the treatment of spinal muscular atrophy and possibly other neurodegenerative human diseases where axonal transport and synaptic defects are implicated.

描述（由申请人提供）：脊柱肌肉萎缩（SMA）是婴儿死亡率的主要遗传原因。 SMA是一种常染色体隐性神经肌肉疾病，其特征是脊髓前角运动神经元退化，导致对称肌肉无力和萎缩。它是由编码生存运动神经元蛋白（SMN）的突变或缺失引起的，这是一种无处不在的mRNA剪接蛋白。仍然未知运动神经元如此易受SMN水平的特定症状以及SMN缺乏症如何有选择地导致运动神经元细胞死亡。目前尚无治愈或治疗方法可以阻止其进展。我们和其他人表明，低水平的SMN导致轴突生长缺陷，2-肌动蛋白mRNA转运受损，并降低运动神经元生长锥的2-肌动蛋白水平。这些发现代表了SMN缺陷神经元中的第一个已知分子缺陷，并提出了SMN的轴突特异性功能。我们假设SMN可以充当轴突生长锥中2-肌动蛋白mRNA颗粒的组装，运输和/或局部翻译的重要辅助因子。轴突mRNA定位的缺陷和2-肌动蛋白的翻译可能有助于SMA典型的轴突功能障碍和神经变性。以前开发SMA治疗的努力并未直接靶向SMN缺陷运动神经元中的轴突缺陷。在这项对NIH融资的翻译研究申请中，我们建议对纠正SMN缺陷运动神经元功能缺陷的药物进行基于细胞的高吞吐量筛选。首先，我们将使用多能干细胞衍生的运动神经元来鉴定可增强2-肌动蛋白mRNA转运到轴突生长锥体的药物。其次，我们将筛选出在生长锥中升高2-肌动蛋白水平的药物。这些筛选中确定的新型药物候选物将通过在培养的原代运动神经元和SMA小鼠模型中进行的一系列测试来验证有效性。鉴于这种疾病的人为损失以及缺乏有效的疗法，我们的目标是将了解SMN在运动神经元中的功能中的最新进展转化为用于治疗SMA的有效药物的开发。公共卫生相关性：我们建议使用干细胞衍生的运动神经元筛查药物以治疗脊柱肌肉萎缩中的轴突缺陷。在轴突和生长锥中引起2-肌动蛋白mRNA和蛋白质水平的分子有可能用作药物，用于治疗轴突运输和突触缺陷的脊柱肌肉萎缩以及其他可能的神经退行性人类疾病。