Molecular Pathphysiology of FSHD muscular dystrophy via genome-wide approaches

通过全基因组方法研究 FSHD 肌营养不良症的分子病理生理学

• 批准号: 7569419
• 负责人: YI-WEN CHEN
• 金额: $ 34.98万
• 依托单位: CHILDREN'S RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-15 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7569419
• 关键词: 4q35; Adult; Affect; Age; Animal Model; Anterior; Apoptosis; Appearance; Belgium; Binding; Binding Sites; Biochemical; Biological Assay; Biopsy; Candidate Disease Gene; Cells; Chromosomes; Clinical; Computer software; Consensus; Creatine Kinase; D4Z4; Data; Dermatomyositis; Development; Disease; Disease model; Doxycycline; Duchenne muscular dystrophy; EMSA; Embryonic Development; Embryonic and Fetal Development; Evaluation; Face; Facioscapulohumeral Muscular Dystrophy; Fibroblasts; Functional disorder; Future; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Genetic; Genetic Transcription; Genome; Goals; Hindlimb; Homeobox; Homeostasis; Homologous Gene; In Vitro; Inflammation; Inherited; Life; Limb Development; Limb structure; Location; Long-Term Effects; Lower Extremity; Luciferases; Mediating; Messenger RNA; Modeling; Molecular; Molecular Profiling; Molecular Target; Monitor; Mus; Muscle; Muscle Fibers; Muscle Weakness; Muscular Atrophy; Muscular Dystrophies; Mutagenesis; Mutation; Myoblasts; Myopathy; Natural regeneration; Neuromuscular Diseases; Onset of illness; Oxidative Stress; Pathogenesis; Pathway interactions; Patients; Phenotype; Phosphotransferases; Play; Predisposition; Principal Investigator; Process; Promoter Regions; Reporter; Reporter Genes; Research; Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Role; Series; Serum; Shoulder; Siblings; Site; Skeletal Muscle; Spinal; Staging; Testing; Tetanus Helper Peptide; Tetracyclines; Time; Tin; Transgenic Mice; Transgenic Model; Transgenic Organisms; Triceps Brachii Muscle; Ubiquitin; Universities; Up-Regulation; Upper arm; base; chromatin immunoprecipitation; derepression; disease phenotype; expression vector; fusion gene; gene function; gene induction; gene interaction; genome-wide; homeobox protein PITX1; homeodomain; in vivo; injured; mouse genome; mouse model; multicatalytic endopeptidase complex; postnatal; programs; promoter; research study; response; sex; skeletal muscle wasting; transcription factor; transgene expression; vector; wasting

DESCRIPTION (provided by applicant): Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscle disorder that is characterized by the progressive weakness and wasting of the muscles from face, upper-arm and shoulder girdle to lower limb. While there is consensus that FSHD is a disorder of transcription and gene regulation, the molecular pathways leading to muscular dystrophy and other unique clinical features of the disease are far from clear. Our preliminary study of whole genome profiles of 125 muscle biopsies representing 12 neuromuscular disorders showed that paired-like homeodomain transcription factor 1 (PITX1) gene was specifically up-regulated in FSHD patients. The significant PITX1 over-expression we observed in FSHD can not be due to inflammation, degeneration/ regeneration, or other "dystrophic" changes in muscle, as no other muscle disease (including juvenile dermatomyositis, Duchenne dystrophy, and others) showed up- regulation. Based on our extensive preliminary data both in vitro and in vivo, we present a model where over-expression of PITX1 in adult muscle invokes key muscle atrophy pathways, and, further, that PITX1 is regulated by DUX4 expression. The goal of this current proposal is to further develop our pathophysiological model to show direct relationships between 4q35 deletions, DUX4, and PITX1. The proposed research relies heavily on temporal series, conducted both in vivo and in vitro. Gene/gene interactions will also be determined. In aim 1, we propose to determine if Pitxl is a direct target of DUX4. We will determine whether a putative DUX4 binding site in the promoter region of Pitxl is functional, and whether it is specifically and directly regulated by DUX4. Additional DUX4 targets will be identified by temporal profiling. Interaction between DUX4 and potential target genes will be determined. In aim 2, we propose to generate and characterize a conditional muscle-specific Pitxl transgenic mouse model. The phenotype will be evaluated for changes in various clinical, functional, biochemical, molecular, and histological parameters. The phenotype of myoblasts, including appearance, proliferation, differentiation and susceptibility to oxidative stress, will also be evaluated. In addition, we will determine whether the disease phenotype is reversible. In aim 3, we will define molecular transcriptional pathways downstream of Pitxl expression using the Pitxl transgenic mouse. Temporal expression profiling will be performed to construct the pathways regulated by Pitxl. Interactions between Pitxl and potential regulatory targets of Pitxl will be further studied. Our preliminary data showed that disease-specific up-regulation of DUX4 and Pitxl and downstream changes of genes involved in muscle wasting might be involved in the pathophysiology of FSHD. The proposed research will identify key players in the pathological cascades of FSHD and define the interactions among them, which could potentially be used for developing treatments of the disease.

描述（由申请人提供）：面肩肱型肌营养不良症（FSHD）是一种常染色体显性肌肉疾病，其特征是从面部、上臂、肩胛带到下肢的肌肉进行性无力和萎缩。虽然人们一致认为 FSHD 是一种转录和基因调控紊乱，但导致肌营养不良症和该疾病其他独特临床特征的分子途径尚不清楚。我们对代表 12 种神经肌肉疾病的 125 份肌肉活检的全基因组图谱进行的初步研究表明，配对样同源域转录因子 1 (PITX1) 基因在 FSHD 患者中特异性上调。我们在 FSHD 中观察到的 PITX1 显着过度表达不可能是由于肌肉的炎症、变性/再生或其他“营养不良”变化所致，因为没有其他肌肉疾病（包括幼年性皮肌炎、杜氏营养不良等）表现出上调。基于我们广泛的体外和体内初步数据，我们提出了一个模型，其中成人肌肉中 PITX1 的过度表达会引发关键的肌肉萎缩途径，而且，PITX1 受到 DUX4 表达的调节。当前提案的目标是进一步开发我们的病理生理学模型，以显示 4q35 缺失、DUX4 和 PITX1 之间的直接关系。拟议的研究很大程度上依赖于在体内和体外进行的时间序列。基因/基因相互作用也将被确定。在目标 1 中，我们建议确定 Pitxl 是否是 DUX4 的直接目标。我们将确定Pitx1启动子区域中的推定DUX4结合位点是否有功能，以及它是否受DUX4特异性和直接调节。其他 DUX4 目标将通过时间分析来识别。 DUX4 和潜在靶基因之间的相互作用将被确定。在目标 2 中，我们建议生成并表征条件肌肉特异性 Pitxl 转基因小鼠模型。将评估表型的各种临床、功能、生化、分子和组织学参数的变化。还将评估成肌细胞的表型，包括外观、增殖、分化和对氧化应激的敏感性。此外，我们将确定疾病表型是否可逆。在目标 3 中，我们将使用 Pitxl 转基因小鼠定义 Pitxl 表达下游的分子转录途径。将进行时间表达谱分析以构建受 Pitxl 调节的途径。 Pitxl 与 Pitxl 潜在监管靶点之间的相互作用将得到进一步研究。我们的初步数据表明，疾病特异性 DUX4 和 Pitxl 的上调以及参与肌肉萎缩的基因的下游变化可能与 FSHD 的病理生理学有关。拟议的研究将确定 FSHD 病理级联中的关键参与者，并确定它们之间的相互作用，这有可能用于开发该疾病的治疗方法。