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: 8204577
• 负责人: Andrea Arnett
• 金额: $ 4.5万
• 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/8204577
• 关键词: Actins; Address; Atrophic; Binding; Biology; Body Weight decreased; C-terminal; Cell Proliferation; Child; Complementary DNA; Complex; Contracture; Cytoskeleton; Duchenne muscular dystrophy; Dystroglycan; Dystrophin; Evaluation; Extracellular Matrix; Gene Transfer; Genes; Glycoproteins; Health; Hereditary Disease; Hypertrophy; 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; 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; Utrophin; Viral; Wasting Syndrome; disease-causing mutation; flexibility; in vivo; insight; mdx mouse; member; muscle degeneration; muscle form; muscle regeneration; novel strategies; 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.

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死性遗传疾病，是由肌营养不良蛋白基因突变引起的严重肌肉消耗性疾病。肌营养不良蛋白是肌营养不良蛋白-糖蛋白复合物（DGC）的核心组分，其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强有力的柔性连接来赋予肌纤维机械稳定性。许多研究已经检查了抗肌萎缩蛋白和DGC的核心组分的功能，然而，关于结合抗肌萎缩蛋白的C-末端部分的DGC的其他成员的功能知之甚少。这些蛋白质中的一些，包括syntrophin和神经元型一氧化氮合酶（nNOS），已记录的信号特性，并可能在肌肉组织中发挥重要的信号作用。我们先前产生了骨骼肌表达Dpi 16的转基因小鼠，并将该转基因引入肌营养不良蛋白缺陷型mdx小鼠，其作为DMD的模型。Dpi 16是肌营养不良蛋白的非肌肉同种型，其缺乏肌动蛋白结合结构域和在全长肌营养不良蛋白同种型中发现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连接，但仍然可以在肌膜上组装和稳定DGC。因此，Dpi 16应该允许肌营养不良蛋白的C-末端部分和其结合伴侣的功能和结构研究，独立于肌营养不良蛋白N-末端和杆结构域的机械功能。我们已经表明，Dpi 16在mdx小鼠的肌肉中具有最小的影响，其中肌营养蛋白被上调以部分补偿肌营养不良蛋白的缺乏。然而，当在严重营养不良的dystrophin：utrophin双敲除（mdx：utrn-/-）小鼠中表达时。Dpi 16表达赋予寿命的显著增加以及关节挛缩和脊柱后凸的形成和进展的延迟。因此，我们建议研究Dp 116介导的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。我们将产生缺失构建体以鉴定Dpi 16的对挽救致死性至关重要的结构域。我们还将评估骨骼肌生物学的各个方面，包括再生，卫星细胞活化，细胞外基质组织和可能受DGC影响的线粒体功能。