Titin in Skeletal Muscle Health and Disease

肌联蛋白在骨骼肌健康和疾病中的作用

• 批准号: 10006114
• 负责人: Henk L. GRANZIER
• 金额: $ 44.71万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10006114
• 关键词: Address; Affect; Atomic Force Microscopy; Awareness; Back; Basic Science; Binding Proteins; Biological Assay; Biology; Biopsy; Cells; Centronuclear myopathy; Clinical; Complex; Coupling; Data; Disease; Dominant-Negative Mutation; Excision; Exons; Gene Expression; Goals; Health; In Vitro; Inherited; Introns; Knowledge; Measures; Mechanics; Microfilaments; Molecular; Mus; Muscle; Muscle Weakness; Muscle function; Mutate; Mutation; Myopathy; Neuromuscular Diseases; Organ; Patients; Physiology; Pilot Projects; Property; Proteins; Proteomics; RNA; RNA Splicing; Research; Respiratory Failure; Respiratory Muscles; Role; Sarcomeres; Skeletal Muscle; Spectrum Analysis; Splice-Site Mutation; Structure; Techniques; Tertiary Protein Structure; Testing; Therapeutic; Transcript; Triad Acrylic Resin; Work; base; connectin; disease phenotype; disease-causing mutation; early onset; exon skipping; experience; experimental study; insight; mouse model; muscle stiffness; novel; protein expression; respiratory; single molecule; therapeutic target; transcriptome sequencing

There is a rapidly increasing awareness of the importance of titin in causing neuromuscular disorders (titinopathies), two of which we focus on in this work, centronuclear myopathy (CNM) and hereditary myopathy with early respiratory failure (HMERF). Titinopathies frequently present early-onset muscle weakness and respiratory difficulty but understanding their underlying mechanisms is held back by our still limited understanding of the functional roles of titin in skeletal muscle. Titin comprises the third myofilament of muscle and spans along the sarcomere, from Z-disk to M-band. Titin’s I-band region functions as a molecular spring that generates passive stiffness with recent studies indicating that passive stiffness affects active force at sub- maximal activation levels. However, it is not known how important titin’s stiffness is to overall skeletal muscle health and if altered stiffness can cause a myopathy. That the importance might be high is suggested by our pilot studies that reveal deranged titin stiffness and reduced active tensions in titinopathy patients with CNM. Aims 1 and 2 address how altering titin-based stiffness affects both passive and active muscle properties and if it can be disease-causing. We will perform mechanical studies on biopsies from titinopathy patients (focus on CNM) as well as study two contrasting mouse models in which the stiffness of titin’s spring region is either increased (PEVK truncation) or reduced (inactivation of Rbm20). The working hypothesis is that altering titin’s spring region alters both passive muscle stiffness and active tension and that this causes myopathy. Aim 2 also studies a novel mouse model that mimics CNM with splice site mutations in titin’s spring region and we will examine the functional consequences at the RNA, protein, structural and functional levels. We also study the A-band segment of titin, specifically the C-zone. This zone has not been studied, it is clinically important as this is where a large number of disease-causing mutations are found. We investigate in Aim 3 a mutation in the C-zone exon 343 which causes HMERF, a myopathy with respiratory muscle involvement that can be fatal. Using a novel HMERF mouse that we made the mechanistic basis of the disease will be studied. Through excision of the mutated titin exon 343, the therapeutic potential of exon skipping for treating HMERF will be tested. With its basic science and translational goals and its in-depth and integrative approach, this application seeks to continue our track record of cutting-edge titin research. Powerful techniques and novel mouse models are in place, pilot data support the guiding hypotheses, and our research team is highly experienced. The proposal will greatly enhance insights in titin biology, titin’s role in muscle disease, and titin’s potential as a therapeutic target.

人们对引起神经肌肉疾病的重要性的认识迅速增加 （滴虫病），我们在这项工作中重点关注的两个，Centronclear肌病（CNM）和遗传性肌病 早期呼吸衰竭（HMERF）。滴虫病经常出现早期发作的肌肉无力和 呼吸困难，但了解其潜在机制被我们仍然有限的 了解钛在骨骼肌中的功能作用。 Titin建立第三个肌肉的肌肉 从Z-Disk到M波段沿着肌膜跨越。 Titin的I波段区域充当分子弹簧 这会产生被动僵硬，最近的研究表明，被动刚度会影响亚ub- 最大激活水平。但是，尚不清楚Titin的刚度对整体骨骼肌肉有多重要 健康和刚度改变会导致肌病。我们的重要性可能很高。 试点研究表明，滴定质量僵硬和CNM患者的主动张力降低。 目标1和2解决了基于滴定质量的刚度如何影响被动和主动肌肉的特性，以及是否如何 这可能是引起疾病的原因。我们将对钛病患者的活检进行机械研究（专注于 CNM）以及研究两个对比的小鼠模型，其中Titin的春季区域的刚度是 增加（PEVK截断）或减少（RBM20失活）。工作假设是改变titin的 春季区域会改变被动肌肉的僵硬和主动张力，这会导致肌病。目标2 还研究了一种新型的小鼠模型，该模型在蒂丁的春季区域模仿CNM与剪接位点突变，我们 将检查RNA，蛋白质，结构和功能水平的功能后果。我们也学习 Titin的A频段段，特别是C区。该区域尚未研究，它在临床上很重要，因为 这是发现大量引起疾病的突变的地方。我们在AIM 3中调查了一个突变 引起HMER的C区外显子343，这是一种具有呼吸肌肉参与的肌病 致命的。使用一种新型的HMER小鼠，我们将疾病的机械基础进行研究。 通过突变的滴定外显子343的惊喜，外显子跳过治疗HMER的治疗潜力 将进行测试。凭借其基础科学和翻译目标及其深入和综合方法， 该应用程序旨在继续我们的尖端titin研究记录。强大的技术和 新颖的鼠标模型已经到位，飞行员数据支持指导假设，我们的研究团队是 经验丰富。该提案将最大程度地增强对泰丁生物学的见解，泰丁在肌肉疾病中的作用， 以及Titin作为治疗目标的潜力。