Costamere Defects in Muscular Dystrophies

肌营养不良症中的肋部缺陷

基本信息

批准号：
8884371
负责人：
JAMES M ERVASTI
金额：
$ 37.82万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-02-01 至 2020-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8884371
关键词：
Ablation Actins Address Animal Model Animals Biochemical Buffers Caliber Cell Maintenance Creatine Kinase Cysteine Data Defect Drops Dystrophin Electrons Fiber Foundations Funding Genetic Immunofluorescence Immunologic Knock-out Knockout Mice Link Maintenance Measurement Measures Mediating Membrane Methodology Microscopic Mitochondria Modification Mus Muscle Muscle Cells Muscle Contraction Muscle Proteins Muscle Weakness Muscle function Muscular Dystrophies Myoglobin Myopathy Natural regeneration Organelles Oxidation-Reduction Peroxidases Phenotype Physiological Protein Isoforms Proteins Proteomics Public Health Reactive Oxygen Species Reagent Role Running Sarcomeres Sarcoplasmic Reticulum Serum Shunt Device Skeletal Muscle Stretching Striated Muscles Structure Sulfhydryl Compounds Testing Time base grasp human disease inhibitor/antagonist knockout animal mdx mouse mouse model novel overexpression oxidation peroxiredoxin 2 prevent public health relevance research study response therapy development

项目摘要

DESCRIPTION (provided by applicant): While abundant sarcomeric actin isoforms are famous for their essential role in striated muscle contraction, low abundance non-muscle "cytoplasmic" actin isoforms (cyto- and cyto-actin) are also emerging as important in the maintenance of specialized structures in normal and diseased skeletal muscle. During this project, we generated and characterized muscle-specific mouse lines lacking either cyto-actin, or cyto-actin, or overexpressing cyto-actin to understand their endogenous functions and role(s) in dystrophin-deficient muscular dystrophy. Interestingly, each cyto-actin or cyto-acin single knockout develops a qualitatively similar phenotype characterized by a progressive myopathy with significant myofiber degeneration/regeneration and muscle weakness. We have shown that 2000-fold muscle-specific overexpression of cyto-actin in dystrophin- deficient mdx mice affords significant protection from eccentric contraction-induced force drop. Our new data suggest that eccentric contraction drives a rapidly-reversible, reactive oxygen species (ROS)-mediated inhibition of sarcomeric contractility that may function to protect dystrophic muscles from myofibrillar damage caused by repeated, high force contractions. Finally, we have obtained new data suggesting that cyto- and cyto-actins collaborate to maintain the functional interaction between mitochondria and sarcoplasmic reticulum. Going forward, we will make use of our unique animal models, isoform-specific reagents and biochemical and physiological methodologies to address fundamental questions about cytoplasmic actins in normal skeletal muscle function and in dystrophin-deficient muscular dystrophy. In aim 1, we will investigate how loss of a key redox buffering protein contributes to eccentric contraction-induced force drop in dystrophic mdx skeletal muscle. In aim 2, we will test the hypothesis that stretch-induced ROS may cause eccentric contraction induced force drop in mdx muscle via reversible oxidative modification of sarcomeric actin or other myofibrillar proteins critical for contractile function. n aim 3, the roles of cyto- and cyto-actins at the interface between mitochondria and the sarcoplasmic reticulum will be investigated through characterization of mouse lines in which cyto-actin and cyto-actins have been knocked out in skeletal muscle individually, or in combination. The results of the proposed studies will definitively address the unique and important contributions of cytoplasmic actin isoforms to the function of normal and diseased skeletal muscle.

描述（由适用提供）：虽然丰富的肉瘤肌动蛋白同工型以其在条纹肌肉收缩中的重要作用而闻名，但低抽象的非肌肉“细胞质”肌动蛋白同工型（Cyto- cyto- cy- cyto-to-Actin）在正常的专用结构中也很重要。在这个项目中，我们产生并表征了缺乏cyto-to-actin或肌动蛋白或过表达的肌肌动蛋白的肌肉特异性小鼠系，以了解其内源性功能和在肌营养不良蛋白缺乏性肌肉肌营养不良中的作用。有趣的是，每个肌肌动蛋白或环-ACIN单敲除质量上具有明显的肌纤维退化/再生和肌肉无力的性肌病。我们已经表明，在肌营养不良蛋白缺陷型的MDX小鼠中，cy-肌动蛋白的200倍肌肉特异性过表达可为偏心收缩诱导的力下降提供明显的保护。我们的新数据表明，偏心收缩驱动了快速可逆的活性氧（ROS）介导的肉瘤收缩性抑制作用，该肉瘤收缩性可能起作用，可以保护营养不良的肌肉免受由重复的高力收缩引起的肌原纤维损伤。最后，我们获得了新的数据，表明肌和cy-to-actins合作以维持线粒体和肌质网之间的功能相互作用。展望未来，我们将利用我们独特的动物模型，同工型特异性试剂以及生化和物理方法，以解决正常骨骼肌功能以及肌营养不良蛋白缺陷肌肉营养不良中的细胞质肌动蛋白的基本问题。在AIM 1中，我们将研究关键的氧化还原缓冲蛋白的损失如何有助于营养不良的MDX骨骼肌偏心收缩引起的力下降。在AIM 2中，我们将测试以下假设：拉伸诱导的ROS可能会通过肉瘤肌动蛋白或其他对收缩功能至关重要的肉瘤肌动蛋白或其他肌原纤维蛋白的可逆氧化物修饰而导致MDX肌肉中的力下降。 n AIM 3，将通过小鼠系的表征来研究to-cyto- cyto-肌动蛋白在线粒体和肌浆网之间的界面中的作用，其中肌肌动蛋白和cyto-cyto-肌动蛋白已在骨骼肌中分别单独或结合。拟议的研究的结果将确定地解决细胞质肌动蛋白同工型对正常骨骼肌和脱落骨骼肌功能的独特和重要贡献。