Orai1 as a Therapeutic Target for Muscular Dystrophy

Orai1 作为肌营养不良症的治疗靶点

基本信息

批准号：
9283626
负责人：
Robert T Dirksen
金额：
$ 23.1万
依托单位：
UNIVERSITY OF ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-07-01 至 2019-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9283626
关键词：
Address Adult Affect Age Aging Antisense Oligonucleotides Calcium Cell membrane Cessation of life Child Clinical Trials Collaborations Consensus Coupling Cytoskeleton Data Development Dominant-Negative Mutation Drug Targeting Duchenne muscular dystrophy Dystrophin Extracellular Matrix Family Fatigue Fiber Functional disorder Future Generations Genes Genetic Transcription Growth and Development function Health Care Costs Healthcare Systems Household Human Incidence Investigation Knockout Mice Lead Life Expectancy Limb-Girdle Muscular Dystrophies Membrane Mitochondria Multiprotein Complexes Mus Muscle Muscle Fatigue Muscle Fibers Muscle Weakness Muscular Atrophy Muscular Dystrophies Mutation Myopathy Necrosis Outcome Pathogenicity Pathway interactions Patient Care Patients Performance Permeability Phenotype Predisposition Proteins Proteolysis Publishing Quality of life Regulation Reporting Research Resistance Role STIM1 gene Sarcoplasmic Reticulum Severities Signal Transduction Skeletal Muscle Stem cells Surface Symptoms Tamoxifen Testing Therapeutic Therapeutic Intervention Translating Translations Treatment Efficacy Wheelchairs base boys combat delta Sarcoglycan exon skipping experience gene therapy improved in vivo inhibitor/antagonist insight mdx mouse molecular drug target mouse model multidisciplinary muscle degeneration muscular dystrophy mouse model novel novel therapeutics overexpression pre-clinical premature sarcopenia sensor skeletal muscle growth symptom treatment targeted treatment therapeutic target tool

项目摘要

Being first reported in 2001, store-operated Ca2+ entry (SOCE) is a relatively new phenomenon in skeletal muscle. SOCE is coordinated by coupling between two proteins: STIM1 calcium sensors in the sarcoplasmic reticulum (SR) and Ca2+-permeable Orai1 channels in the transverse tubule (TT) membrane. SOCE enhances muscle growth/development, limits fatigue, and promotes fatigue-resistant type I fiber specification. On the other hand, SOCE dysfunction contributes to muscle weakness/fatigue in aging, exacerbates muscular dystrophy, and mutations in STIM1 and Orai1 genes result in debilitating myopathies. The picture that emerges is that tight regulation of STIM1/Orai1-dependent SOCE activity is critical for optimal muscle performance such that increases or decreases in SOCE activity can lead to muscle fatigue, sarcopenia, and myopathy. Thus, Orai1-dependent SOCE represents a provocative potential therapeutic target for muscular dystrophy. We recently demonstrated that SOCE promotes skeletal muscle growth, limits muscle fatigue, and exacerbates the severity of muscular dystrophy in dystrophin- (mdx) and δ-sarcoglycan-deficient (sgcd-/-) mice. For this R21 application, we developed tamoxifen-inducible, muscle-specific Orai1 knockout mice in order to determine the specific role of Orai1-dependent Ca2+ entry in skeletal muscle in the dystrophic phenotypes observed in mdx and sgcd-/- mice, established mouse models of Duchene Muscular Dystrophy and Limb Girdle Muscular Dystrophy, respectively. We also established a collaboration with CalciMedica Inc. to evaluate the efficacy of systemic delivery of 4 potent new investigational SOCE channel inhibitors in mitigating the myopathic phenotypes of mdx and sgcd-/- mice. We will use these new research tools and collaborations, together with a comprehensive multi-disciplinary experimental approach, to evaluate the efficacy of inhibiting Orai1-dependent SOCE as a therapeutic intervention for muscular dystrophy. Based on our published and preliminary data, we hypothesize that partial inhibition of Orai1-dependent Ca2+ entry in skeletal muscle provides protection against myopathy in mouse models of muscular dystrophy without enhancing susceptibility to muscle fatigue. The validity of this central hypothesis will be rigorously tested in two Specific Aims. Aim 1 will use tamoxifen-inducible, muscle-specific Orai1 knockout mice to determine the impact of partial post-developmental, muscle-specific reduction of SOCE on muscular dystrophy. Aim 2 will determine the therapeutic efficacy of systemic administration of new generation Orai1 channel inhibitors obtained through a collaboration from CalciMedica Inc. to reduce the dystrophic phenotypes of mdx and sgcd-/- mice. The results of this project will provide needed preclinical evidence regarding the therapeutic potential of targeting Orai1-dependent Ca2+ entry as a treatment for muscular dystrophy.

商店操纵的 Ca2+ 进入 (SOCE) 于 2001 年首次被报道，是骨骼中相对较新的现象。 SOCE 通过两种蛋白质之间的耦合进行协调：肌浆中的 STIM1 钙传感器。横管 (TT) 膜中的网状 (SR) 和 Ca2+ 通透性 Orai1 通道增强。肌肉生长/发育，限制疲劳，并促进抗疲劳 I 型纤维规格。另一方面，SOCE 功能障碍会导致衰老过程中的肌肉无力/疲劳，使肌肉恶化营养不良以及 STIM1 和 Orai1 基因突变会导致衰弱性肌病。严格调节 STIM1/Orai1 依赖性 SOCE 活性对于最佳肌肉性能至关重要，例如 SOCE 活动的增加或减少会导致肌肉疲劳、肌肉减少症和肌病。 Orai1 依赖性 SOCE 代表了肌营养不良症的一个令人兴奋的潜在治疗靶点，我们最近证明 SOCE 可以促进骨骼肌生长，限制肌肉疲劳，并加剧肌营养不良蛋白（mdx）和 δ-肌聚糖缺陷（sgcd-）的肌营养不良症的严重程度。 /-) 小鼠，为了确定 R21 的具体作用，我们开发了他莫昔芬诱导型肌肉特异性 Orai1 敲除小鼠。我们还与 CalciMedica Inc. 建立了合作，以在 mdx 和 sgcd-/- 小鼠中观察到的营养不良表型中 Orai1 依赖性 Ca2+ 进入骨骼肌的情况，分别建立了 Duchene 肌营养不良症和肢带肌营养不良症小鼠模型。全身给药 4 种有效的新研究 SOCE 通道抑制剂在减轻 mdx 和肌病表型方面的功效我们将使用这些新的研究工具和合作，以及全面的多学科实验方法，根据我们已发表的初步研究来评估抑制 Orai1 依赖性 SOCE 作为肌肉营养不良症治疗干预措施的功效。根据数据，我们发现部分抑制骨骼肌中Orai1依赖性Ca2+的进入可以在肌营养不良小鼠模型中提供针对肌病的保护，而不增加对肌肉疲劳的易感性。这一中心假设的有效性将得到严格测试。在两个具体目标中，目标 1 将使用他莫昔芬诱导的肌肉特异性 Orai1 敲除小鼠来确定 SOCE 的部分发育后肌肉特异性减少对肌营养不良症的影响，目标 2 将确定全身给药的治疗效果。通过与 CalciMedica Inc. 合作获得的新一代 Orai1 通道抑制剂，可减少 mdx 和 sgcd-/- 小鼠的营养不良表型。该项目的结果将提供。需要有关以 Orai1 依赖性 Ca2+ 进入为目标治疗肌营养不良症的治疗潜力的临床前证据。