Mechanisms of neuromuscular degeneration in SBMA

SBMA 神经肌肉变性的机制

• 批准号: 10471367
• 负责人: ANDREW P LIEBERMAN
• 金额: $ 53.82万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10471367
• 关键词: 1 year old; AR gene; Androgen Receptor; Antisense Oligonucleotides; Atrophic; Biochemical Genetics; Biological Assay; Cell Differentiation process; Cells; Chronic; Complement; Data; Defect; Development; Disease; Disease model; Exercise Tolerance; Foundations; Future; Gene Targeting; Genetic Transcription; Glutamine; Goals; Histologic; Hormones; Human; Laboratories; Longevity; Metabolic; Modeling; Molecular Chaperones; Motor Neuron Disease; Motor Neurons; Mus; Muscle Weakness; Muscular Atrophy; Neuromuscular Diseases; Nuclear Translocation; Pathogenesis; Pathogenicity; Pathology; Patients; Peripheral; Phenotype; Public Health; Publishing; Research Design; Skeletal Muscle; Spinal; Spinal Cord; Testing; Time; Tissues; Toxic effect; Translating; Ubiquitination; Work; base; cell type; chaperone machinery; experimental study; functional restoration; human embryonic stem cell line; in vivo; induced pluripotent stem cell; innovation; insight; knock-down; men; motor neuron degeneration; neuromuscular; neuromuscular system; neuron loss; novel; novel therapeutic intervention; overexpression; polyglutamine; proteotoxicity; public health relevance; receptor; receptor expression; skeletal muscle wasting; small molecule; spinal and bulbar muscular atrophy; targeted treatment; therapy development; transcription factor; treatment duration; uptake

ABSTRACT Spinal and bulbar muscular atrophy (SBMA) is a degenerative disorder of the neuromuscular system caused by a CAG/glutamine tract expansion in the androgen receptor (AR) gene. The polyglutamine AR (polyQ AR) undergoes hormone-dependent nuclear translocation and unfolding, steps that are essential to toxicity and to the development of progressive muscle weakness in men. Although it was long considered that lower motor neurons are the primary targets of degeneration in SBMA, recent studies from our laboratory and others have established the importance of peripheral polyQ AR expression in disease. This work highlights a central contribution of polyQ AR expression in skeletal muscle to weakness and atrophy. Based on these findings, we have developed an innovative model of SBMA pathogenesis in which degeneration of the neuromuscular system begins with toxic effects in skeletal muscle and progresses over time to involve spinal motor neuron degeneration. Here, we propose to test this model of disease pathogenesis in gene targeted mice (AR113Q mice) expressing polyQ AR at endogenous levels and in appropriate cell types. The objective of this application is to experimentally test our novel model of disease pathogenesis. This model forms our central hypothesis and is supported by a rigorous foundation of published and preliminary data. Here, we will use two complementary approaches to test our central hypothesis: First, we will use antisense oligonucleotides (ASOs) to knock-down expression of polyQ AR selectively in peripheral tissues or CNS of symptomatic AR113Q mice and determine effects on late onset motor neuron degeneration. Second, we will restore function of a critical transcriptional regulator in skeletal muscle that contributes to SBMA skeletal muscle atrophy and then determine the extent to which this influences the AR113Q phenotype, including motor neuron degeneration. These aims will be complemented by studies designed to leverage the endogenous cellular machinery that regulates polyQ AR degradation in order to eliminate proteotoxicity in disease relevant human cells. We will use biochemical, genetic, and histological assays to establish beneficial effects of AR targeted ASOs administered to symptomatic AR113Q mice (Aim 1), determine the extent to which increased MEF2 function rescues the AR113Q phenotype (Aim 2), and establish effects of targeting the Hsp90/Hsp70 chaperone machinery in SBMA models (Aim 3). These studies are expected to experimentally test our proposed model of disease pathogenesis and provide a strong foundation for developing targeted therapies to treat SBMA patients.

抽象的 脊柱和鳞茎肌肉萎缩（SBMA）是由神经肌肉系统的退化性疾病 雄激素受体（AR）基因中的CAG/谷氨酰胺道的扩张。聚谷氨酰胺AR（Polyq AR） 经历依赖激素的核易位和展开，对毒性至关重要的步骤 男性进行性肌肉无力的发展。尽管长期认为较低的电动机 神经元是SBMA变性的主要目标，我们的实验室的最新研究和其他研究 确定了外周polyq AR在疾病中的重要性。这项工作突出了一个中心 骨骼肌中Polyq AR表达对无力和萎缩的贡献。基于这些发现，我们 已经开发了一种创新的SBMA发病机理模型，其中神经肌肉系统的变性 从骨骼肌的有毒作用开始，然后随着时间的流逝而发展，涉及脊柱运动神经元 退化。在这里，我们建议在基因靶向小鼠中测试这种疾病发病机理模型（AR113Q 小鼠）在内源水平和适当的细胞类型中表达PolyQ AR。此应用的目的 是在实验测试我们的新型疾病发病机理模型。该模型构成了我们的中心假设和 由严格的已发布和初步数据的基础支持。在这里，我们将使用两个补充 测试我们的中心假设的方法：首先，我们将使用反义寡核苷酸（ASO）进行敲门 在有症状的AR113Q小鼠的外围组织或中枢性中选择性地表达Polyq AR并确定 对晚期运动神经元变性的影响。其次，我们将恢复关键转录的功能 骨骼肌的调节剂有助于SBMA骨骼肌萎缩，然后确定 这影响了AR113Q表型，包括运动神经元变性。这些目标将是 补充旨在利用调节Polyq AR的内源性细胞机制的研究 降解以消除相关人类细胞中的蛋白质毒性。我们将使用生化，遗传， 和组织学测定，以建立针对性的AR靶向ASO的有益作用 AR113Q小鼠（AIM 1），确定增加MEF2功能的程度可挽救AR113Q表型 （AIM 2），并建立针对SBMA模型中HSP90/HSP70伴侣机械的效果（AIM 3）。 预计这些研究将在实验中测试我们提出的疾病发病机理模型，并提供 为开发靶向疗法治疗SBMA患者的强大基础。