Zebrafish models of muscular dystrophies

描述（由申请人提供）：肌肉萎缩症是一组以骨骼肌进行性无力和变性为特征的原发性遗传性疾病。该项目的长期目标是利用两种不同基因形式的脊椎动物模型来了解肌肉萎缩症的分子基础，并为患有这些衰弱疾病的患者开发治疗方法。先天性刚性脊柱肌营养不良症（RSMD1）在出生或婴儿期早期表现出来，由SEPN1基因突变引起，而肌强直性肌营养不良症（MMD）通常出现在成年期，最近与BIN1基因的错误剪接有关。有趣的是，SEPN1和BIN1都编码了对t小管的生物发生和功能很重要的蛋白质，t小管是骨骼肌中负责三联体兴奋-收缩耦合的结构。为了进一步阐明这些分子相关疾病的病理生理学，并在大范围内筛选小分子疗法，需要适当的脊椎动物模型。斑马鱼由于其体积小、透明、高增殖能力和基因组特征明确，近年来在发育生物学中成为一种强大的遗传工具，并被提出作为RSMD1和MMD的可靠模型。该项目的具体目标是1)在斑马鱼中创建和表征bin1和sepn1基因的靶向敲除，以及2)开发这些突变体用于高通量药物筛选，以鉴定具有治疗RSMD1和MMD潜力的先导化合物。这些研究的成功结论将增加对这些疾病的基本生物学，受影响的系统和导致骨骼肌无力的机制的一般理解。此外，对减缓或防止骨骼肌紊乱的小分子的鉴定将为可能用于治疗肌肉萎缩症和其他相关神经肌肉疾病的新疗法的临床前测试奠定基础。

DESCRIPTION (provided by applicant): Muscular dystrophies are a diverse group of primary inherited disorders characterized by progressive weakness and degeneration of skeletal muscle. The long-term goals of this project are to understand the molecular basis of muscular dystrophies using vertebrate models of two genetically distinct forms, and to develop therapies for patients with these debilitating conditions. Congenital rigid spine muscular dystrophy (RSMD1) manifests at birth or in early infancy and is caused by mutations in the SEPN1 gene, whereas myotonic muscular dystrophy (MMD) commonly presents in adulthood and has recently been associated with mis-splicing of the BIN1 gene. Interestingly, SEPN1 and BIN1 both encode proteins important for the biogenesis and function of T-tubules, the structures in skeletal muscles responsible for excitation-contraction coupling at the triads. To further elucidate the pathophysiology of these molecularly related conditions, and to screen small molecule therapeutics on a large scale, appropriate vertebrate models are required. Zebrafish, due to their small size, transparency, high proliferative capacity, and well-characterized genome, have recently emerged as a powerful genetic tool in developmental biology and are proposed here as reliable models for RSMD1 and MMD. The specific aims of this project are 1) to create and characterize targeted knockouts of the bin1 and sepn1 genes in zebrafish, and 2) to develop these mutants for use in high throughput drug screens to identify lead compounds with therapeutic potential for RSMD1 and MMD. The successful conclusion of these studies will increase general understanding of the basic biology of these disorders, the affected systems, and the mechanisms that lead to skeletal muscle weakness. Furthermore, the identification of small molecules that slow or prevent derangements of skeletal muscle will set the stage for preclinical testing of new therapies that may be used to treat patients with muscular dystrophy and other related neuromuscular diseases.