Signaling Mechanisms of the Dystrophin-Glycoprotein Complex

肌营养不良蛋白-糖蛋白复合物的信号传导机制

• 批准号: 7810367
• 负责人: Andrea Arnett
• 金额: $ 3.26万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-15 至 2013-01-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7810367
• 关键词: Actins; Address; Atrophic; Binding; Biology; Body Weight decreased; C-terminal; Cell Proliferation; Child; Complementary DNA; Complex; Contracture; Critiques; Cytoskeleton; Duchenne muscular dystrophy; Dystroglycan; Dystrophin; Evaluation; Extracellular Matrix; Gene Transfer; Genes; Glycoproteins; Hereditary Disease; Hypertrophy; Individual; Injection of therapeutic agent; Joints; Knock-out; Kyphosis deformity of spine; Laboratories; Length; Limb structure; Link; Longevity; Maintenance; Mechanics; Mediating; Mitochondria; Modeling; Monitor; Mus; Muscle; Muscle Fibers; Muscular Dystrophies; N-terminal; Natural regeneration; Nitric Oxide Synthase Type I; Outcome; Pathology; Pathway interactions; Phenotype; Play; Property; Protein Isoforms; Proteins; Recombinants; Role; Sarcolemma; Series; Signal Transduction; Skeletal Muscle; Structure; Techniques; Testing; Transgenes; Transgenic Mice; Transgenic Organisms; Update; Utrophin; Viral; Wasting Syndrome; disease-causing mutation; flexibility; in vivo; insight; mdx mouse; meetings; member; muscle degeneration; muscle form; muscle regeneration; novel strategies; public health relevance; regenerative; respiratory; restoration; retinal rods; satellite cell; syntrophin; vector

DESCRIPTION (provided by applicant): Duchenne muscular dystrophy (DMD), the most common lethal genetic disorder in children, is a severe muscle-wasting disease caused by mutations in the dystrophin gene. Dystrophin is a core component of the dystrophin-glycoprotein complex (DGC), which is thought to confer mechanical stability to the muscle fiber by providing a strong, flexible connection between the internal actin cytoskeleton and the extracellular matrix. Numerous studies have examined the function of dystrophin and the core components of the DGC, however, less is known about the function of other members of the DGC that bind the C-terminal portion of dystrophin. Some of these proteins, including syntrophin and neuronal nitric oxide synthase (nNOS), have documented signaling properties and may play important signaling roles in muscle tissue. We previously generated transgenic mice with skeletal muscle expression of Dpi 16 and have introduced this transgene into dystrophin-deficient mdx mice, which serve as a model for DMD. Dpi 16 is a non-muscle isoform of dystrophin that lacks the actin-binding domain and the majority of the rod domain found in the full length dystrophin isoform. It is postulated that Dpi 16 has no direct, mechanical link to the actin cytoskeleton, but can still assemble and stabilize the DGC at the sarcolemma. Thus, Dpi 16 should permit functional and structural studies of both the C-terminal portion of dystrophin and its binding partners, independent of the mechanical function of the dystrophin N-terminus and rod domain. We have shown that Dpi 16 has minimal effect in muscles of mdx mice, in which utrophin is upregulated to partially compensate for the lack of dystrophin. However, when expressed in the severely dystrophic dystrophin:utrophin double knockout (mdx:utrn-/-) mouse. Dpi 16 expression imparts a dramatic increase in longevity and a delay in the formation and progression of joint contractures and kyphosis. Thus, we propose to study the structural and functional mechanism through which Dp116-mediate(j DGC assembly leads to phenotypic rescue in mdx:utrn-/- mice and explore possible signaling roles of the DGC in skeletal muscle. We will generate deletion constructs to identify the domains of Dpi 16 that are critical for rescue of lethality. We will also evaluate aspects of skeletal muscle biology, including regeneration, satellite cell activation, extracellular matrix organization, and mitochondrial function that may be influenced by the DGC. PUBLIC HEALTH RELEVANCE: This proposal addresses questions regarding the function of dystrophin. Understanding of the function of Dpi 16 and the dystrophin-glycoprotein complex in severely dystrophic mice will provide insight into the mechanism of muscle degeneration, which may suggest novel strategies for therapy of muscular dystrophy. NOTE: The critiques of individual reviewers are provided below in an essentially unedited form. These critiques were prepared prior to the review meeting and may not have been updated or revised subsequent to the discussion at the meeting. Therefore, they may not fully reflect the final opinions of the individual reviewers at the close of group discussion or the final majority opinion of the group. The Resume and Summary of Discussion above summarizes the final outcome of the group discussion.

描述（由申请人提供）：杜氏肌营养不良症（DMD）是儿童中最常见的致命性遗传性疾病，是一种由肌营养不良蛋白基因突变引起的严重肌肉萎缩性疾病。肌营养不良蛋白是肌营养不良蛋白-糖蛋白复合物 (DGC) 的核心成分，它被认为通过在内部肌动蛋白细胞骨架和细胞外基质之间提供牢固、灵活的连接来赋予肌纤维机械稳定性。许多研究已经检查了肌营养不良蛋白和 DGC 核心成分的功能，然而，对于结合肌营养不良蛋白 C 端部分的 DGC 其他成员的功能知之甚少。其中一些蛋白质，包括肌营养蛋白和神经元一氧化氮合酶 (nNOS)，已记录信号特性，并可能在肌肉组织中发挥重要的信号作用。我们之前培育了骨骼肌表达 Dpi 16 的转基因小鼠，并将这种转基因引入肌营养不良蛋白缺陷的 mdx 小鼠中，该小鼠可作为 DMD 的模型。 Dpi 16 是肌营养不良蛋白的非肌肉亚型，缺乏肌动蛋白结合结构域和全长肌营养不良蛋白亚型中的大部分杆状结构域。据推测，Dpi 16 与肌动蛋白细胞骨架没有直接的机械联系，但仍然可以在肌膜处组装和稳定 DGC。因此，Dpi 16 应该允许对肌营养不良蛋白的 C 端部分及其结合伙伴进行功能和结构研究，而独立于肌营养不良蛋白 N 端和杆结构域的机械功能。我们已经证明，Dpi 16 对 mdx 小鼠的肌肉影响极小，其中肌营养不良蛋白上调以部分补偿肌营养不良蛋白的缺乏。然而，当在严重营养不良肌营养不良蛋白：肌营养不良蛋白双敲除 (mdx:utrn-/-) 小鼠中表达时。 Dpi 16 表达可显着延长寿命并延缓关节挛缩和脊柱后凸的形成和进展。因此，我们建议研究 Dp116-介导（j DGC 组装导致 mdx:utrn-/- 小鼠表型拯救的结构和功能机制，并探索 DGC 在骨骼肌中可能的信号传导作用。我们将生成缺失构建体来识别对于拯救致死性至关重要的 Dpi 16 结构域。我们还将评估骨骼肌的各个方面 生物学，包括可能受 DGC 影响的再生、卫星细胞激活、细胞外基质组织和线粒体功能。 公共卫生相关性：该提案解决了有关肌营养不良蛋白功能的问题。了解 Dpi 16 和肌营养不良蛋白-糖蛋白复合物在严重营养不良小鼠中的功能将有助于深入了解肌肉退化的机制，这可能会为治疗肌营养不良症提出新的策略。 注：下面以基本未经编辑的形式提供了个别审稿人的批评。这些批评是在审查会议之前准备的，在会议讨论后可能没有更新或修订。因此，它们可能无法完全反映小组讨论结束时个别审稿人的最终意见或小组的最终多数意见。上面的讨论摘要和摘要总结了小组讨论的最终结果。