Slow myosin binding protein-C in skeletal muscle physiology

骨骼肌生理学中的慢肌球蛋白结合蛋白-C

• 批准号: 10461813
• 负责人: Sakthivel Sadayappan
• 金额: $ 46.13万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10461813
• 关键词: ATP phosphohydrolase; Ablation; Actins; Actomyosin; Address; Adult; Arthrogryposis; Birth; Calcium; Cardiac Myosins; Classification; Clinical; Contracture; DNA Sequence Alteration; Data; Development; Disease; Disease Progression; Distal; Exhibits; Fiber; Functional disorder; Gene Mutation; Genes; Genetic; Goals; Health; Histopathology; Human; Impairment; In Vitro; Intervention; Joints; Kinetics; Knockout Mice; Lead; Light; Link; Live Birth; MM form creatine kinase; Mediating; Molecular; Mus; Muscle; Muscle Development; Muscle Weakness; Muscle function; Muscular Atrophy; Mutation; Myopathy; Myosin ATPase; Outcome; Pathologic; Penetrance; Perinatal; Phenotype; Physical therapy; Physiological; Post-Translational Protein Processing; Protein Family; Protein Isoforms; Proteins; Regulation; Research; Respiration Disorders; Respiratory Diaphragm; Respiratory Muscles; Role; Sarcomeres; Secondary to; Signal Pathway; Signal Transduction; Skeletal Muscle; Skeletal Muscle Myosins; Soleus Muscle; Striated Muscles; Syndrome; Tamoxifen; Testing; Transgenic Mice; Tremor; Variant; Wild Type Mouse; base; citrate carrier; defined contribution; experimental study; extensor digitorum; improved; in vivo; insight; mouse model; muscle physiology; muscular structure; myosin-binding protein C; new therapeutic target; novel; overexpression; paralogous gene; perinatal development; perinatal period; postnatal; prenatal; programs; promoter; pup; skeletal; skeletal muscle weakness; therapeutic target; translational study; wasting

PROJECT SUMMARY: The distal arthrogryposes (DA) are a heterogeneous group of disorders characterized by congenital nonprogressive joint contractures associated with muscle weakness. Depending on the gene involved and the specific mutation, inheritance is typically autosomal dominant with variable expression and incomplete penetrance. Current clinical classification identifies eleven different discrete syndromes with several associated with mutations in sarcomere genes including slow skeletal myosin binding protein-C (MYBPC1). Recently, a homozygous recessive mutation in MYBPC1 was linked to a severe form of DA, lethal congenital contracture syndrome type 4 (LCCS4). Despite the increasing association of DA syndromes with specific genetic mutations, molecular mechanisms that underlie skeletal muscle weakness that presumably lead to disabling contractures are poorly understood. As these mechanisms are unknown and, specifically, little is known about how sMyBP-C regulates muscle function in vivo, current therapies are largely ineffective and relegated to symptomatic physical therapy. The overall long-term goal of our research program has been to define the contribution of the myosin binding protein-C (MyBP-C) proteins in health and disease. These sarcomeric-specific proteins are known to regulate striated muscle contractility via modulating actomyosin function. Three MyBP-C paralogs exist, namely slow skeletal MyBP-C (sMyBP-C), fast skeletal (fMyBP-C), and cardiac MyBP-C, and encoded by separate genes. The specific goal of this proposal is to define the physiologic mechanisms underlining how mutations in sMyBP- C lead to muscle dysfunction and contractures. In our preliminary studies, we determined that mouse pups that are homozygous global sMyBP-C null (Mybpc1-/-), similar to the human LCCS4 phenotype, all died within the first day of birth and exhibited tremors secondary to muscle atrophy. We demonstrated that muscle creatine kinase Cre- and human a-skeletal actin-Cre/Tamoxifen-mediated sMyBP-C ablation (Mybpc1fl/fl) resulted in significant muscle weakness in postnatal and adult stages, respectively. Finally, we showed in transgenic mice overexpressing Mybpc1Tg under the control of the human a-skeletal actin promoter that sMyBP-C replaces fMyBP-C impairing fast muscle type function. Based on these data, we hypothesize that sMyBP-C acts as a key regulator of striated muscle formation and function in both slow and fast muscle types. The planned experiments will systematically define whether (i) sMyBP-C is essential for normal formation of muscle in prenatal and perinatal stages, (ii) sMyBP-C is required for skeletal muscle function in postnatal and adult stages, and (iii) sMyBP-C and fMyBP-C transcomplement each other. We anticipate that addressing these key questions will drive mechanistic understanding of how sMyBP-C regulates skeletal muscle physiology across developmental stages. Consequently, this proposal will identify therapeutic targets to improve muscle function in those afflicted with DA diseases.

项目摘要：远端关节弯曲 (DA) 是一组异质性疾病，其特征是 由与肌肉无力相关的先天性非进行性关节挛缩引起。取决于基因 涉及和特定的突变，遗传通常是常染色体显性遗传，具有可变表达和 不完全外显。目前的临床分类确定了十一种不同的离散综合征，其中有几种 与肌节基因突变相关，包括慢骨骼肌球蛋白结合蛋白-C (MYBPC1)。 最近，MYBPC1 的纯合隐性突变与一种严重的 DA（致死性先天性遗传病）有关。 挛缩综合征 4 型 (LCCS4)。尽管 DA 综合征与特定遗传的关联性越来越大 突变，骨骼肌无力的分子机制，可能导致残疾 人们对挛缩知之甚少。由于这些机制是未知的，特别是，人们对这些机制知之甚少。 sMyBP-C 如何调节体内肌肉功能，目前的疗法基本上无效，只能用于 对症物理治疗。 我们研究计划的总体长期目标是确定肌球蛋白结合的贡献 健康和疾病中的 Protein-C (MyBP-C) 蛋白质。已知这些肌节特异性蛋白质可以调节 通过调节肌动球蛋白功能来调节横纹肌收缩力。存在三个 MyBP-C 旁系同源物，即慢速 骨骼 MyBP-C (sMyBP-C)、快速骨骼 (fMyBP-C) 和心脏 MyBP-C，并由不同的基因编码。 该提案的具体目标是定义强调 sMyBP 突变如何发生的生理机制。 C导致肌肉功能障碍和挛缩。在我们的初步研究中，我们确定小鼠幼崽 是纯合的全局 sMyBP-C null (Mybpc1-/-)，与人类 LCCS4 表型相似，全部在 出生第一天，并表现出继发于肌肉萎缩的震颤。我们证明了肌肉肌酸 激酶 Cre- 和人 a-骨骼肌动蛋白-Cre/他莫昔芬介导的 sMyBP-C 消融 (Mybpc1fl/fl) 导致 分别在产后和成年阶段出现明显的肌肉无力。最后，我们在转基因小鼠中展示了 在 sMyBP-C 取代的人类 a-骨骼肌动蛋白启动子的控制下过度表达 Mybpc1Tg fMyBP-C 损害快肌型功能。 基于这些数据，我们假设 sMyBP-C 是横纹肌形成的关键调节因子， 在慢肌和快肌类型中都有功能。计划的实验将系统地定义是否（i） sMyBP-C 对于产前和围产期肌肉的正常形成至关重要，(ii) sMyBP-C 是必需的 用于产后和成年阶段的骨骼肌功能，以及 (iii) sMyBP-C 和 fMyBP-C 反式补体 彼此。我们预计，解决这些关键问题将推动人们对如何 sMyBP-C 调节各个发育阶段的骨骼肌生理学。因此，该提案将 确定改善 DA 疾病患者肌肉功能的治疗靶点。