The Role of Germline Mutations of the Ras/MAPK Pathway on Skeletal Myogenesis

Ras/MAPK 途径种系突变对骨骼肌生成的作用

基本信息

批准号：
8904608
负责人：
Katherine Anna Rauen
金额：
$ 35.33万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-01-01 至 2018-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8904608
关键词：
Address Affect BRAF gene Cell Cycle Cell physiology Costello syndrome Cutaneous Data Development Effectiveness Exhibits Feedback Foundations Functional disorder Genes Genetic Germ-Line Mutation Goals Growth HRAS gene Histopathology In Vitro Individual Knowledge LEOPARD Syndrome MAP2K1 gene MAPK14 gene Malignant Neoplasms Mediating Medical Genetics Mitogen-Activated Protein Kinases Modeling Morbidity - disease rate Muscle Muscle Development Muscle Fibers Muscle Weakness Muscle hypotonia Mutation Myoblasts Myopathy Nerve Neurofibromatosis 1 Noonan Syndrome Pathology Pathway interactions Patients Phenotype Play Process Proliferating Publishing Regulation Research Role Signal Pathway Signal Transduction Skeletal Muscle Small Interfering RNA Staging Syndrome System Testing Therapeutic Intervention Tissues base congenital anomaly design human MAPK14 protein in vivo in vivo Model inhibitor/antagonist insight mouse model muscle form myogenesis novel patient population research study skeletal small molecule

项目摘要

DESCRIPTION (provided by applicant): Skeletal myogenesis is a dynamic process in which muscle precursor cells first proliferate and then fuse to form multinucleated myotubes that ultimately mature into skeletal muscle fibers. The Ras/Mitogen-activated protein kinase (MAPK) pathway, a well-studied cancer pathway, plays a critical role in the regulation of myogenesis, particularly during the switch from myoblast proliferation to differentiation. Early studies have demonstrated that high levels of Ras/MAPK pathway activation disrupt early myogenesis. However, there are critical gaps in our understanding as to how Ras and its downstream effector cascades regulate and affect vital steps in myogenesis during development. The "RASopathies", a newly defined group of medical genetic syndromes, are one of the largest groups of multiple congenital anomaly syndromes known, affecting more than 1 in 1000 individuals. Caused by germline mutations in various key genes encoding components of the Ras/MAPK pathway, the RASopathies share a common phenotypic feature of congenital hypotonia, or weak muscles. Costello syndrome (CS) and cardio-facio-cutaneous (CFC) syndrome are two RASopathies with the most severe muscle phenotype. We have recently identified the presence of a novel myopathy, defined as an intrinsic abnormality of muscle that is not attributable to nerve dysfunction, in individuals with CS and CFC. In addition, our preliminary studies provide support for our hypothesis that dysregulation of Ras/MAPK signaling disrupts both early myogenesis by inhibiting myoblast differentiation, and later stages of muscle development following differentiation, by inhibiting muscle growth. The goal of the proposed research is to understand how myogenesis is affected by Ras/MAPK dysregulation, as well as the specific mechanism of action underlying this effect. We will examine novel germline mutations identified in the RASopathies to help us understand how Ras dysregulation affects muscle development. Our Specific Aims are designed to determine 1) how skeletal muscle is disrupted by dysregulation of Ras/MAPK pathway signaling in CS and CFC; 2) the mechanisms by which Ras/MAPK dysregulation causes disruption of skeletal muscle myogenesis, and 3) if small molecule inhibitors and small interfering RNAs (siRNA) can reverse the effects of dysregulated Ras/MAPK signaling during myogenesis. We will use mouse models of CS and CFC to elucidate how skeletal muscle is disrupted by distinguishing what aspect of the myopathy is due to inhibition of myoblast differentiation and what is due to muscle fiber formation from post-differentiation inhibition of muscle growth. We will elucidate the specific mechanisms by which Ras/MAPK signal dysregulation inhibits myogenesis using primary myoblasts derived from CS and CFC mouse models. Results derived from those experiments will be used to evaluate the effectiveness of rationally chosen inhibitors to correct the developmental effects of a dysregulated Ras pathway using in vitro and in vivo models of myogenesis.

描述（由申请人提供）：骨骼肌发生是一个动态过程，其中肌肉前体细胞首先增殖，然后融合以形成多核肌管，最终成熟成骨骼肌纤维。 RAS/有丝分裂原激活的蛋白激酶（MAPK）途径是一种良好的癌症途径，在肌发生调节中起着至关重要的作用，尤其是在从肌细胞增殖到分化的转换期间。早期研究表明，高水平的RAS/MAPK途径激活破坏了早期肌发生。但是，关于RAS及其下游效应器级联反应如何调节并影响发育过程中肌发生的重要步骤的理解，存在关键的差距。新定义的一组医学遗传综合症是“ RASOPATIES”，是已知的多个先天性异常综合征的最大群体之一，影响了1000多人中有1个以上。由编码RAS/MAPK途径成分的各种关键基因中的种系突变引起的，Rasopathies具有先天性低位症或弱肌肉的共同表型特征。 Costello综合征（CS）和心脏 - 毛皮（CFC）综合征是两种具有最严重肌肉表型的rasopathies。我们最近确定了一种新型的肌病的存在，该肌病被定义为在CS和CFC的个体中，肌肉的内在异常不归因于神经功能障碍。此外，我们的初步研究为我们的假设提供了支持，即RAS/MAPK信号的失调通过抑制成肌细胞分化和分化后肌肉发育后的后期阶段，通过抑制肌肉生长来破坏早期肌发生。拟议的研究的目的是了解肌发生如何受到RAS/MAPK失调的影响，以及这种效果的基本作用机理。我们将检查在rasopathies中鉴定出的新型种系突变，以帮助我们了解RAS失调如何影响肌肉发育。我们的具体目的旨在确定1）CS和CFC中RAS/MAPK途径信号传导失调的骨骼肌如何破坏骨骼肌肉； 2）RAS/MAPK失调会导致骨骼肌肌发生的破坏的机制； 3）如果小分子抑制剂和小的干扰RNA（siRNA）可以逆转肌发生过程中RAS/MAPK信号的影响。我们将使用CS和CFC的小鼠模型来阐明骨骼肌如何通过区分肌病的哪个方面是由于肌细胞分化的抑制以及由于肌肉纤维形成与肌肉后分化后的抑制作用所致。我们将阐明使用源自CS和CFC小鼠模型的主要成肌细胞抑制RAS/MAPK信号失调的特定机制。从这些实验中得出的结果将用于评估合理选择的抑制剂的有效性，以使用体外和体内肌发生模型校正失调的RAS途径的发育效果。