Preclinical Development of a Novel Therapeutic Strategy for LGMD2B

描述（由申请人提供）：本申请的长期目标是促进我们目前无法治愈的肢体带状肌营养不良2B型（LGMD2B）的新治疗策略的临床前开发。肌肉萎缩症是一种发病率和死亡率较高的肌肉萎缩疾病。LGMD2B是由异铁蛋白基因突变导致蛋白表达改变（异铁蛋白病）引起的。受损膜的修复缺陷通过异质蛋白依赖的膜融合已被牵连。然而，我们对异铁素是否调节众所周知的囊泡融合相关过程（例如，乙酰胆碱受体（AChR）的回收和神经肌肉连接- nmj突触传递的维持）的了解还存在空白。利用秀丽隐杆线虫LGMD2B模型中强大的药物遗传学工具，我们已经确定了fer1在调节NMJ突触传递中的新作用（初步研究）。我们对突触病或肌无力成分的鉴定具有巨大的分类学和翻译意义。有趣的是，在一项小型试点试验（初步研究）中，乙酰胆碱酯酶抑制剂（Acetylcholine Esterase Inhibitors, AChEI）的使用提高了LGMD2B A/J小鼠模型的存活率，并提出了一种假设，即由dysferlin缺乏引起的NMJ缺陷可以使用AChEI作为候选治疗药物来提高神经肌肉传递效率并改善LGMD2B结果。作为一个特定的目标，我们提出了一个精心设计的，原则性的研究，以完成成功临床前开发这种候选治疗所需的初步步骤，并测试我们的翻译假设。我们将进行一项治疗性试验，我们对8个月大的a /J小鼠进行8个月的AChEI治疗。治疗潜力将采用体内和体外手段进行分析，以确定营养不良表型的改善。该项目的相关性和健康相关性在于，开展这些研究，我们将确保更清楚地了解分子和功能病理生理学，并促进我们针对LGMD2B的新治疗策略的临床前开发。

DESCRIPTION (provided by applicant): The long term goals of this proposal are to facilitate preclinical development of our novel therapeutic strategy for the currently incurable Limb Girdle Muscular Dystrophy Type 2B (LGMD2B). The muscular dystrophies are muscle wasting disorders with increased morbidity and mortality. LGMD2B is caused by dysferlin gene mutations leading to altered protein expression (dysferlinopathy). Deficient repair of damaged membranes via dysferlin-dependent membrane fusion has been implicated. However, lacunae exist in our knowledge of whether dysferlin regulates well-known vesicle fusion related processes (e.g. Acetylcholine Receptor (AChR) recycling & maintenance of synaptic transmission at the neuromuscular junction-NMJ). Using powerful pharmacogenetic tools available in the C. elegans model of LGMD2B, we have identified a novel role for fer-1 in the regulation of NMJ synaptic transmission (Preliminary studies). Our identification of a synaptopathic or myasthenic component has tremendous nosological and translational implications. Interestingly, Acetylcholine Esterase Inhibitors (AChEI) administration improves the survival of the A/J mouse model of LGMD2B in a small pilot trial (Preliminary Studies) and suggests the hypothesis that the NMJ deficit caused by dysferlin deficiency is amenable to treatment using AChEI as a candidate therapeutic to increase the efficiency of neuromuscular transmission and improve LGMD2B outcomes. As a specific aim we propose a well-designed, proof-of-principle study in order to complete the preliminary steps required for successful preclinical development of this candidate therapeutic and test our translational hypothesis. We will undertake a therapeutic trial where we treat 8 month old A/J mice with AChEI for 8 months. Therapeutic potential will be will be assayed using in vivo and ex vivo means to determine improvement of the dystrophic phenotype. The relevance and health relatedness of this project is that undertaking these studies we will ensure clearer understanding of the molecular and functional patho-physiology as well as facilitate preclinical development of our novel therapeutic strategy for LGMD2B. PUBLIC HEALTH RELEVANCE: The health relatedness of this project is that by completion of our aim we will ensure clearer understanding of the molecular and functional patho-physiology of limb-girdle muscular dystrophy Type 2B (LGMD2B) as well as facilitate preclinical development of our novel therapeutic strategy for LGMD2B.