Genetic modifiers of motor neuron degeneration

描述（由申请人提供）：本申请的主要目的是在肌萎缩性侧索硬化症（ALS）的果蝇模型中发现新的疾病途径。最近，RNA结合蛋白TDP-43 （43 kDa TAR dna结合蛋白）的显性突变与ALS有因果关系。此外，在ALS患者退行性运动神经元中经常观察到泛素阳性、不溶性的TDP-43聚集体，这表明通过突变或表观遗传的TDP-43的失调是该疾病的一个促成事件。我们已经建立了一个果蝇TDP-43蛋白病模型，其中人类TDP-43在果蝇运动神经元中的表达导致年龄依赖性瘫痪和死亡。在该模型中，TDP-43保留了核表达模式，这表明TDP-43不需要聚集就能引起运动神经元功能障碍。基于这些发现，我们假设核基因表达的tdp -43依赖性变化是神经退行性变的原因。与这一观点一致的是，对TDP-43转基因果蝇的基因表达分析发现，细胞通路的失调与神经退行性变可能存在关联。本研究的目标是利用果蝇TDP-43模型来获得对TDP-43依赖性神经变性的新见解。这项拨款包括两个具体目标。在Aim 1中，我们将进行微阵列和RIP-Chip研究，以鉴定运动神经元中的TDP-43 RNA靶点。在Aim 2中，我们将使用候选方法和无偏方法筛选tdp -43依赖性神经变性的遗传修饰剂。联合研究应阐明肌萎缩侧索硬化症和相关蛋白病变的神经退行性变机制，从而可能导致新的治疗选择。

DESCRIPTION (provided by applicant): The principle objective of this application is to discover novel disease pathways in a Drosophila melanogaster model of amyotrophic lateral sclerosis (ALS). Recently, dominant mutations in the RNA binding protein TDP-43 (43 kDa TAR DNA-binding protein) have been causally linked to ALS. In addition, ubiquitin-positive, insoluble aggregates of TDP-43 are frequently observed in degenerating motor neurons of ALS patients, suggesting that deregulation of TDP-43 through mutation or epigenetically is a precipitating event in this disease. We have generated a fruit-fly model of TDP-43 proteinopathy in which the expression of human TDP-43 in the motor neurons of flies leads to age- dependent paralysis and death. In this model, TDP-43 retains a nuclear expression pattern, suggesting that TDP-43 need not aggregate to cause motor neuron dysfunction. Based on these findings we hypothesized that TDP-43-dependent changes in nuclear gene expression are responsible for neurodegeneration. Consistent with this idea, gene expression analysis of TDP-43 transgenic flies identified deregulation of cellular pathways with plausible links to neurodegeneration. The goal of the present proposal is to use the Drosophila TDP-43 model to gain new insights into TDP-43-dependent neurodegeneration. The grant encompasses two specific aims. In Aim 1 we will perform microarray and RIP-Chip studies to identify TDP-43 RNA targets in motor neurons. In Aim 2 we will perform screens for genetic modifiers of TDP-43-dependent neurodegeneration, using both candidate and unbiased approaches. The combined studies should illuminate mechanisms of neurodegeneration in ALS and related proteinopathies that may lead to new therapeutic options. PUBLIC HEALTH RELEVANCE: ALS is an intractable condition that exerts severe tolls on affected patients, their families, and caregivers. Comprehensive approaches aimed at identifying the operative mechanisms in this disease are urgently needed. We believe that the fruit fly model of ALS to be explored in this proposal will provide important clues regarding ALS pathogenesis that may lead to new therapies.