Therapeutic target discovery in Drosophila models of Nemaline Myopathy

描述（由申请人提供）：我们的长期目标是寻找治疗线状肌病（NM）的有效疗法。NM是最常见的非营养不良型先天性肌病，在某些人群中发病率为1/20,000。这是一种缓慢或非进行性疾病，其特征是在受影响的肌肉组织中存在线状体，肌肉无力和缺乏肌肉再生。NM是一种不同严重程度的异质组肌病：不同类型的NM可以从新生儿致死到轻度成人发病。迄今为止，这种疾病没有有效的治疗方法。9个不同基因的突变与NM有关，其中6个基因编码骨骼肌肌节细丝相关蛋白，包括Cofilin 2 （CFL2）。基因突变与疾病严重程度或其他表型之间不存在关系。异质组NM患者的基因表达谱揭示了NM的一致特征；这些基因表达的变化如何导致疾病的发生和/或严重程度尚不清楚。我们利用果蝇CFL2同源基因双星（tsr）的突变，建立了一种新的果蝇NM模型。这个模型显示了NM的特征：线状的身体，肌肉无力，在严重的情况下，过早死亡。在我们不太严重的情况下，肌肉功能降低，但肌节没有明显改变。我们将使用我们的新模型来解决这种疾病的现有治疗方法的关键空白，以及我们对NM特征基因对疾病发展和严重程度的贡献的理解。利用快速生成时间、表型的可重复性和外显性、可用的遗传工具以及执行成本有效、相对高通量筛选的能力，我们提出了两个目标：首先，我们将筛选FDA批准的药物库，以确定延迟或消除NM症状的药物。这些研究依赖于我们稳健的模型，我们最近开发的药物应用方法，以及我们为高通量筛选而简化的分析。我们希望找到FDA批准的影响NM形成或严重程度的药物。在第二部分，我们将确定NM特征基因如何影响NM疾病的严重程度。我们将首先评估轻度和强NM条件下的基因表达谱。验证后，我们将把这组基因与我们的合作者Alan Beggs博士生成的患者NM数据进行比较。在我们的果蝇模型中，类似调控的保守基因将被分析其对疾病的贡献。这些数据将增强我们对纳米异质性的理解，为药物有效性提供见解，并为未来的药物开发提供靶点。总之，本提案中概述的工作将为NM提供新的视角：我们将确定一个简短的药物清单和临床相关基因，可以通过我们的研究来验证

DESCRIPTION (provided by applicant): Our long-term goal is to find effective therapeutics for treatment of Nemaline myopathy (NM). NM is the most common form of non-dystrophic congenital myopathy, having an incidence of 1/20,000 in some populations. It is a slow or non-progressive disease, characterized by the presence of Nemaline bodies in the affected muscle tissue, by muscle weakness and by the absence of muscle regeneration. NM is a heterogeneous group of myopathies of variable severity: different types of NM can range from neonatal lethal to mild adult onset. To date, there is no effective treatment for this disease. Mutations in nine different genes have been linked to NM, with six of these encoding skeletal muscle sarcomere thin filament-associated proteins, including Cofilin 2 (CFL2). No relationships exist between gene mutations and disease severity or other phenotypes. Gene expression profiling of a heterogeneous group of NM patients uncovered a consistent signature for NM; how these changes in gene expression contribute to disease onset and/or severity is not clear. We have developed a novel Drosophila model of NM, using mutations in the Drosophila CFL2 ortholog, twinstar (tsr). This model displays the hallmarks of NM: Nemaline bodies, muscle weakness and, in the severe condition, premature death. In our less severe condition, muscle function is reduced without gross alterations to the sarcomere. We will use our novel model to address the critical gaps in both available treatments for this disease and in our understanding of the contributions of NM signature genes to disease development and severity. Taking advantage of the fast generation time, reproducibility and penetrance of the phenotype, the genetic tools available, and the ability to perform cost effective, relatively high throughput screens, we propose two aims: In the first, we will screen an FDA approved drug library to identify drugs that delay or eliminate NM symptoms. These studies depend on our robust model, our recently developed methods for drug application, and our assays streamlined for such a high throughput screen. We expect to find FDA approved drugs that impact the formation or severity of NM. In the second, we will determine how NM signature genes contribute to NM disease severity. We will first assess gene expression profiles in our mild and strong NM conditions. After validation, we will compare this set of genes with patient NM data generated by our collaborator, Dr. Alan Beggs. Conserved genes that are similarly regulated will then be analyzed for their contribution to disease in our fly model. These data will enhance our understanding of NM heterogeneity, provide insights to drug effectiveness and supply targets for future drug development. Together the work outlined in this proposal with shed new light on NM: we will identify a short list of drugs and clinically relevant genes that can be validated, via our collaboration with Dr. Beggs, first in vertebrate and mammalian disease models and, ultimately, in patients.