Development of a Porcine Model of Duchenne Muscular Dystrophy

描述(申请人提供)：Duchenne肌营养不良症(DMD)是一种X连锁隐性遗传病，由DMD基因突变引起，发病率为3500名男婴中有1名。功能性肌营养不良蛋白的丧失会导致骨骼肌和心肌的进行性退化。尽管我们对这种疾病的了解有了很大的进步，在开发新的治疗方法方面也取得了进展，DMD仍然是一种致命的疾病。人们对DMD的大部分了解都来自于对缺乏dystrophin的动物的研究，特别是小鼠和狗的模型。虽然营养不良的小鼠对机制研究很有用，但它不能形成典型的DMD患者的肌肉无力表型。犬模型更能代表人类的DMD，但由于表型的极端变异性，很难进行研究。犬类模型还受到突变选择有限、巨额费用和社会接受问题的困扰。在这些模型中显示出希望的治疗策略尚未成功地转化为临床。迫切需要一种更准确、更一致地复制人类DMD临床表现的动物模型。我们的目标是在猪身上建立一种改进的DMD模型。我们认为，猪模型比现有模型有几个优势。基因打靶现在可以在猪身上使用，这将为设计与患者相关的突变提供机会。猪克隆技术将允许生产出基因相同的营养不良猪，并可能减少表型严重程度的变异性。此外，与狗相比，猪的生产成本更低，更容易饲养，也不会像同伴动物那样面临同样的伦理问题。该项目的最终目标是开发和商业化以DMD为目标的猪，作为Duchenne肌营养不良症的模型。我们打算通过结合基因打靶和体细胞核移植来创建一个携带人类常见DMD突变的猪模型来实现这一点。这份提案概述了我们创建和表征针对DMD的猪的计划。鉴定将包括评估肌营养不良蛋白缺乏的分子和生化后果，以及骨骼肌和心肌表型的功能评估。我们还将通过测试基于核酸的疗法来验证DMD猪作为翻译模型的有效性。这种动物模型将为学术和商业研究团体提供一个更好地了解DMD以及开发和测试新的治疗策略的机会

DESCRIPTION (provided by applicant): Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by mutations in the DMD gene with a prevalence of 1 in 3500 male births. The consequent loss of functional dystrophin results in the progressive degeneration of skeletal and cardiac muscle. Despite significant progress in our understanding of this disease and advances in the development of new therapeutic approaches, DMD remains a fatal disease. Much of what is known about DMD has come from studying dystrophin-deficient animals, particularly murine and canine models. While useful for mechanistic studies, dystrophic mice fail to develop the muscle weakness phenotype that is typical of DMD in patients. The canine models are more representative of human DMD, but are difficult to study due to extreme phenotypic variability. The canine models also suffer from a limited choice of mutations, significant expense, and social acceptance concerns. Therapeutic strategies that have shown promise in these models have yet to be successfully translated to the clinic. An animal model that more accurately and consistently replicates the clinical manifestations of human DMD is sorely needed. Our objective is to create an improved model of DMD in the pig. We believe a porcine model offers several advantages over the existing models. Gene targeting is now available in pigs and would provide an opportunity to engineer patient-relevant mutations. Porcine cloning technology would allow the production of genetically identical dystrophic pigs and could yield reduced variability in phenotype severity. Also, pigs are less expensive to produce and easier to house than dogs and don't face the same ethical concerns as companion animals. The ultimate goal of this project is to develop and commercialize DMD-targeted pigs as a model of Duchenne muscular dystrophy. We intend to accomplish this by combining gene targeting and somatic cell nuclear transfer to create a porcine model harboring a common human DMD mutation. This proposal outlines our plans for the creation and characterization of DMD-targeted pigs. Characterization will include an assessment of the molecular and biochemical consequences of dystrophin deficiency as well as a functional evaluation of the skeletal and cardiac muscle phenotype. We will also validate the DMD pig as a translational model by testing a nucleic acid-based therapy. This animal model will provide the academic and commercial research communities an opportunity to better understand DMD and to develop and test new therapeutic strategies