Genetic modifiers of motor neuron degeneration

描述(由申请人提供)：本申请的主要目标是在肌萎缩侧索硬化症(ALS)的果蝇黑腹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)的显性突变被认为与ALS有关。此外，在ALS患者退变的运动神经元中经常观察到TDP-43泛素阳性的不溶性聚集体，这表明TDP-43通过突变或表观遗传学的失控是该病的诱发事件。我们已经建立了TDP-43蛋白病变的果蝇模型，在该模型中，人TDP-43在果蝇运动神经元中的表达会导致年龄依赖性瘫痪和死亡。在这个模型中，TDP-43保留了核表达模式，表明TDP-43不需要聚集而导致运动神经元功能障碍。基于这些发现，我们假设依赖于TDP-43的核基因表达的变化是导致神经退变的原因。与这一想法一致的是，对TDP-43转基因果蝇的基因表达分析发现，与神经退化有关的细胞通路出现了松弛。本提案的目标是使用果蝇TDP-43模型来获得对TDP-43依赖的神经退行性变的新见解。这笔赠款包括两个具体目标。在目标1中，我们将进行微阵列和RIP芯片研究，以确定运动神经元中的TDP-43RNA靶标。在目标2中，我们将使用候选和无偏见的方法对TDP-43依赖的神经退行性变的遗传修饰物进行筛选。联合研究将阐明ALS的神经变性机制和相关的蛋白质病，这可能会导致新的治疗选择。 与公共卫生相关：肌萎缩侧索硬化症是一种难治性疾病，对受影响的患者、他们的家人和照顾者造成严重的费用。迫切需要全面的方法来确定这种疾病的运作机制。我们相信，这项提议中将探索的ALS果蝇模型将为ALS的发病机制提供重要线索，并可能导致新的治疗方法。

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.