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.

摘要 脊髓延髓肌萎缩症（SBMA）是一种神经肌肉系统的退行性疾病， 雄激素受体（AR）基因中CAG/谷氨酰胺束扩增。聚谷氨酰胺AR（polyQ AR） 经历依赖于细胞核转位和展开，这些步骤对毒性和 男性逐渐出现的肌肉无力尽管长期以来人们认为， 神经元是SBMA退化的主要目标，我们实验室和其他人最近的研究表明， 确立了外周polyQ AR表达在疾病中的重要性。这项工作突出了一个中央 骨骼肌中polyQ AR表达对虚弱和萎缩的贡献。基于这些发现，我们 已经开发出一种SBMA发病机制的创新模型，其中神经肌肉系统的退化 开始于骨骼肌中的毒性作用，并随着时间的推移发展到累及脊髓运动神经元 退化在这里，我们建议在基因靶向小鼠（AR 113 Q）中测试这种疾病发病机制的模型 小鼠）以内源性水平和在适当的细胞类型中表达polyQ AR。本申请的目的 是通过实验测试我们的疾病发病机制新模型。这个模型构成了我们的中心假设， 它得到了已发表和初步数据的严格基础的支持。在这里，我们将使用两个互补的 方法来测试我们的中心假设：首先，我们将使用反义寡核苷酸（ASO）敲低 在有症状的AR 113 Q小鼠的外周组织或CNS中选择性表达polyQ AR，并确定 对迟发性运动神经元变性的影响。其次，我们将恢复一个关键的转录功能， 调节剂在骨骼肌，有助于SBMA骨骼肌萎缩，然后确定的程度， 这会影响AR 113 Q表型，包括运动神经元变性。这些目标将是 辅以旨在利用调节polyQ AR的内源性细胞机制的研究 在某些实施方案中，所述药物组合物可降解以消除疾病相关的人细胞中的蛋白毒性。我们会用生化的，遗传的， 和组织学测定，以确定向有症状的人施用AR靶向ASO的有益作用。 AR 113 Q小鼠（目标1），确定MEF 2功能增加挽救AR 113 Q表型的程度 (Aim 2），并建立SBMA模型中靶向Hsp 90/Hsp 70分子伴侣机制的作用（目的3）。 这些研究有望在实验上检验我们提出的疾病发病机制模型，并提供一种新的诊断方法。 为开发治疗SBMA患者的靶向疗法奠定了坚实的基础。