Preclinical Development of a Novel Therapeutic Strategy for LGMD2B

描述（由申请人提供）：本提案的长期目标是促进我们针对目前无法治愈的肢带型肌营养不良2B型（LGMD 2B）的新型治疗策略的临床前开发。肌营养不良症是具有增加的发病率和死亡率的肌肉消耗病症。LGMD 2B由dysferlin基因突变引起，导致蛋白质表达改变（dysferlin病）。已涉及通过dysferlin依赖性膜融合对受损膜的缺陷修复。然而，我们对dysferlin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）再循环和神经肌肉接头-NMJ处突触传递的维持）的认识存在空白。使用强大的药物遗传学工具，在C。elegans模型的LGMD 2B，我们已经确定了一个新的作用，为fer-1的调节NMJ突触传递（初步研究）。我们对突触病变或肌无力成分的鉴定具有巨大的疾病分类学和翻译意义。有趣的是，乙酰胆碱酯酶抑制剂（AChEI）给药在小型试点试验（初步研究）中改善了LGMD 2B的A/J小鼠模型的存活率，并提出了以下假设：由dysferlin缺乏引起的NMJ缺陷适合使用AChEI作为候选治疗剂来治疗，以增加神经肌肉传递的效率并改善LGMD 2B结果。作为一个具体的目标，我们提出了一个精心设计的，原理验证研究，以完成成功的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试验，其中我们用AChEI治疗8个月大的A/J小鼠8个月。将使用体内和离体方法测定治疗潜力，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LGMD 2B新型治疗策略的临床前开发。 公共卫生相关性：该项目的健康相关性在于，通过完成我们的目标，我们将确保更清楚地了解肢带型肌营养不良症2B型（LGMD 2B）的分子和功能病理生理学，并促进我们对LGMD 2B的新型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.