Basis of Muscle Dysfunction in Malignant Hyperthermia and Central Core Disease

恶性高热和中央核心疾病中肌肉功能障碍的基础

• 批准号: 7105819
• 负责人: SUSAN L HAMILTON
• 金额: $ 24.66万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7105819
• 关键词: gene mutation; muscle

DESCRIPTION (provided by applicant): The skeletal muscle ryanodine receptor (RYR1) regulates Ca2+ release from the sarcoplasmic reticulum (SR) stores and is mutated in human central core disease (CCD) and in the pharmacogenetic syndrome, malignant hyperthermia (MH). Although MH and CCD mutations in RyR1 are thought to alter SR Ca2+ release channel function and muscle excitation-contraction (EC) coupling, the mechanisms by which these effects result in phenotypic changes in muscle characteristic of these disorders are unknown. This project will use transgenic MH and CCD knock-in mice to provide detailed analyses of the fundamental mechanisms by which RYR1 disease mutations alter in vivo muscle function. The long-term goal of this project is to define the cellular/molecular mechanisms and principles by which MH/CCD mutations alter Ca2+ homeostasis and excitation-contraction (EC) coupling in intact muscle. Our overall hypothesis is: MH and CCD mutations in MH/CCD regions 1 and 2 enhance voltage- and Ca2+-gated SR release by altering crucial intra and intermolecular interactions within RYR1 and between RYR1 and the voltage dependent Ca2+ channel in the t-tubule membrane, while CCD-selective mutations in the region 3 pore region of RyR1 disrupt Ca2+ permeation through the channel. To test this hypothesis, we propose to: 1) Create three new MH/CCD mouse lines and analyze the effects of the mutations on muscle contractile properties in response to caffeine and temperature, 2) Analyze the effects of the mutations on RYR1 structure, 3) Assess the effects of MH/CCD mutations in RyR1 on Ca2+ homeostasis and bi-directional DHPR-RyR1 coupling in myotubes and adult muscle fibers obtained from MH/CCD knock-in mice, and 4) Evaluate the effects of MH/CCD mutations on in situ release channel sensitivity to activation by RyR1 ligands and local increases in junctional Ca2+. This application brings together two collaborators, both highly committed to elucidating fundamental mechanisms of MH and CCD pathophysiology, but who approach the problems in very different, but complementary ways. This union will result in a uniquely interdisciplinary project that will determine the mechanisms by which MH/CCD disease mutations alter RyR1 structure and regulation, subcellular Ca2+ transport/handling mechanisms, muscle EC coupling, and SR Ca2+ storage/sequestration. Results will have broad implications for other disorders of Ca2+ dysregulation in [truncated in application]

描述（由申请人提供）：骨骼肌兰尼碱受体（RYR1）调节肌浆网（SR）储存的Ca2+释放，并在人类中枢核心疾病（CC​​D）和药物遗传学综合征、恶性高热（MH）中发生突变。尽管 RyR1 中的 MH 和 CCD 突变被认为会改变 SR Ca2+ 释放通道功能和肌肉兴奋收缩 (EC) 耦合，但这些效应导致这些疾病的肌肉特征表型变化的机制尚不清楚。该项目将使用转基因 MH 和 CCD 敲入小鼠来详细分析 RYR1 疾病突变改变体内肌肉功能的基本机制。该项目的长期目标是确定 MH/CCD 突变改变完整肌肉中 Ca2+ 稳态和兴奋收缩 (EC) 耦合的细胞/分子机制和原理。我们的总体假设是：MH/CCD 区域 1 和 2 中的 MH 和 CCD 突变通过改变 RYR1 内以及 RYR1 与 t 管膜中电压依赖性 Ca2+ 通道之间关键的分子内和分子间相互作用来增强电压和 Ca2+ 门控 SR 释放，而 RyR1 区域 3 孔区域中的 CCD 选择性突变通过以下方式破坏 Ca2+ 渗透： 频道。为了检验这一假设，我们建议：1) 创建三个新的 MH/CCD 小鼠品系，并分析突变对咖啡因和温度响应下的肌肉收缩特性的影响，2) 分析突变对 RYR1 结构的影响，3) 评估 RyR1 中的 MH/CCD 突变对肌管和成体中 Ca2+ 稳态和双向 DHPR-RyR1 偶联的影响 从 MH/CCD 敲入小鼠获得的肌纤维，4) 评估 MH/CCD 突变对原位释放通道对 RyR1 配体激活的敏感性和连接 Ca2+ 局部增加的影响。该应用汇集了两位合作者，他们都高度致力于阐明 MH 和 CCD 病理生理学的基本机制，但他们以截然不同但互补的方式解决问题。这一联合将产生一个独特的跨学科项目，该项目将确定 MH/CCD 疾病突变改变 RyR1 结构和调节、亚细胞 Ca2+ 转运/处理机制、肌肉 EC 耦合和 SR Ca2+ 储存/隔离的机制。结果将对 [应用中截断] 的其他 Ca2+ 失调疾病产生广泛的影响