Role of CUGBP1 in skeletal muscle wasting in myotonic dystrophy

CUGBP1 在强直性肌营养不良骨骼肌消耗中的作用

• 批准号: 7804948
• 负责人: Amanda Joy Whipple
• 金额: $ 3.65万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7804948
• 关键词: 3' Untranslated Regions; Address; Adult; Alternative Splicing; Antibodies; Binding Proteins; Biological Assay; Cardiac; Cause of Death; Cell Nucleus; Chemicals; Dependovirus; Direct Lytic Factors; Disease; Doxycycline; Duchenne muscular dystrophy; Event; Exercise stress test; Exhibits; Gene Targeting; Genes; Half-Life; Heart; Histology; Human; Injection of therapeutic agent; Injury; Insulin Resistance; Limb-Girdle Muscular Dystrophies; Mediating; Merosin; Modeling; Mus; Muscle; Muscle Proteins; Muscle function; Muscular Dystrophies; Myotonia; Myotonic Dystrophy; Natural regeneration; Neuromuscular Diseases; Nuclear; Pathway interactions; Patients; Phenocopy; Phenotype; Phosphorylation; Play; Prevalence; Protein Kinase C; Protein Kinase C Inhibitor; Proteins; Public Health; RNA; RNA Splicing; Recombinant adeno-associated virus (rAAV); Reporting; Role; Sampling; Side; Skeletal Muscle; Specificity; Symptoms; Testing; Tetracyclines; Therapeutic; Time; Tissues; Toxin; Trans-Activators; Transgenic Mice; Trinucleotide Repeats; Two-Dimensional Gel Electrophoresis; Up-Regulation; Weight; Western Blotting; congenital muscular dystrophy; gain of function; improved; inhibitor/antagonist; injured; knock-down; mouse model; muscle degeneration; muscular dystrophy mouse model; notexin; prevent; protein expression; research study; response; skeletal muscle wasting; small hairpin RNA; ward; wasting

DESCRIPTION (provided by applicant): Myotonic dystrophy (DM) is the most common adult onset muscular dystrophy. DM type 1 (DM1) is a multi-systemic neuromuscular disease caused by a CTG expansion in the 3' untranslated region of the DMPK gene. The repeat-containing RNA retained in the nucleus sequesters the MBNL1 splicing factor and leads to up-regulation of the CUGBP1 splicing factor. Misregulated alternative splicing plays a critical role in the disease mechanism and has been directly attributed to two disease symptoms, myotonia and insulin resistance. The ability of repeat-containing RNA to induce other disease symptoms such as skeletal muscle wasting, the leading cause of death in patients, is not known. In Specific Aim 1, the prevalence of splicing changes and alterations in the levels of splicing regulators in different muscular dystrophies will be determined using tissue from six muscular dystrophy mouse models. In Specific Aim 2, the role of CUGBP1 in skeletal muscle wasting will be investigated. CUGBP1 is aberrantly up-regulated in DM1 patients and a DM1 mouse model with a strong wasting phenotype. To determine if increased CUGBP1 is necessary for wasting in this DM1 mouse model, CUGBP1 will be knocked down by delivery of shRNA via an adeno-associated virus. Then, the muscle integrity will be tested by exercise tests, muscle weight, and muscle histology. To determine if increased CUGBP1 is sufficient to induce wasting, mice with doxycycline-inducible and skeletal muscle specific expression of CUGBP1 have been generated and will be examined for muscle function and wasting. In Specific Aim 3, the involvement of PKC in CUGBP1 up-regulation will be determined. In DM1 heart tissue and an inducible DMl heart model, CUGBP1 up-regulation in response to expanded CUG repeats occurs through a PKC-dependent phosphorylation event resulting in hyperphosphorylated and stabilization of CUGBP1. PKC activity and CUGBP1 hyperphosphorylation will be determined in skeletal muscle from the DMl mouse model. PKC inhibition by Bis-IX treatment will be explored as a potential therapeutic approach to inhibit CUGBP1 up-regulation and prevent muscle wasting in the DM1 mouse model. These proposed experiments address a very important question in the field about the cause of muscle wasting in myotonic dystrophy. The mechanisms at play may be more broadly applicable to other neuromuscular diseases and trinucleotide repeat diseases. Public health statement: The primary cause of death in myotonic dystrophy patients is due to the severe skeletal muscle wasting. This proposal aims to determine the cause of skeletal muscle wasting using a myotonic dystrophy mouse model and potentially prevent the wasting using a chemical inhibitor.

描述（由申请人提供）：强直性肌营养不良（DM）是最常见的成人发病型肌营养不良。1型糖尿病（DM 1）是由DMPK基因3'非翻译区CTG扩增引起的多系统性神经肌肉疾病。保留在细胞核中的含有重复序列的RNA螯合MBNL 1剪接因子，并导致CUGBP 1剪接因子的上调。错误调节的选择性剪接在疾病机制中起关键作用，并且已直接归因于两种疾病症状，肌强直和胰岛素抵抗。含有重复序列的RNA诱导其他疾病症状（如骨骼肌萎缩，患者死亡的主要原因）的能力尚不清楚。在特定目标1中，将使用来自六种肌营养不良小鼠模型的组织确定不同肌营养不良中剪接变化和剪接调节因子水平改变的患病率。在具体目标2中，将研究CUGBP 1在骨骼肌萎缩中的作用。CUGBP 1在DM 1患者和具有强消耗表型的DM 1小鼠模型中异常上调。为了确定在该DM 1小鼠模型中增加的CUGBP 1是否是消耗所必需的，将通过经由腺相关病毒递送shRNA来敲低CUGBP 1。然后，将通过运动试验、肌肉重量和肌肉组织学测试肌肉完整性。为了确定增加的CUGBP 1是否足以诱导消耗，已经产生了具有强力霉素诱导的和骨骼肌特异性表达的CUGBP 1的小鼠，并将检查肌肉功能和消耗。在具体目标3中，将确定PKC参与CUGBP 1上调。在DM 1心脏组织和诱导型DM 1心脏模型中，响应于扩增的CUG重复序列的CUGBP 1上调通过PKC依赖性磷酸化事件发生，导致CUGBP 1的过度磷酸化和稳定化。将在来自DM 1小鼠模型的骨骼肌中测定PKC活性和CUGBP 1过度磷酸化。通过Bis-IX处理的PKC抑制将被探索为抑制CUGBP 1上调和预防DM 1小鼠模型中肌肉萎缩的潜在治疗方法。这些拟议的实验解决了一个非常重要的问题，在该领域的原因，肌肉萎缩的强直性肌营养不良症。这种机制可能更广泛地适用于其他神经肌肉疾病和三核苷酸重复疾病。公共卫生声明：强直性肌营养不良患者死亡的主要原因是由于严重的骨骼肌萎缩。该提案旨在使用强直性肌营养不良小鼠模型确定骨骼肌萎缩的原因，并使用化学抑制剂潜在地预防萎缩。