Modeling Mutant Profilin 1 Toxicity and ALS in vivo

描述（由申请人提供）：肌萎缩侧索硬化症（ALS，也称为Lou Gehrig病）是一种致命的神经退行性疾病，可杀死运动神经元，导致瘫痪和死亡。运动神经元变性的机制尚不清楚，这种疾病目前无法治愈。10%的ALS病例是家族性的，90%是散发性的。已经鉴定出许多基因突变导致家族性ALS，其包括SOD 1、ALS 2、VAPB、senataxin、dynactin、angiogenin、TDP-43、FUS、UBQLN 2和c9 orf 72基因中的突变。通过研究这些突变体在细胞和动物模型中引起神经变性的机制，我们对疾病机制的理解取得了进展。最近，通过多年的遗传学研究，我们发现了导致ALS的profilin 1基因的新突变。Profilin是一种肌动蛋白结合蛋白，参与调节肌动蛋白动力学和其他重要的细胞信号传导过程。我们在培养细胞中的初步实验表明，PFN 1突变体可以形成细胞内聚集体，主要破坏肌动蛋白聚合和生长锥形态，导致轴突生长的抑制。基于这些观察，我们假设突变型profilin 1通过功能获得型机制引起神经退行性变。为了验证这一假设，我们建议构建和分析过表达突变型和野生型profilin 1的转基因小鼠。结果将提供支持或反对这一假设的证据。此外，如果突变型profilin 1的过表达导致运动神经元变性，则该实验还将产生一种新的ALS小鼠模型，可供ALS研究界用于探索运动神经元变性的机制和测试治疗策略。

DESCRIPTION (provided by applicant): Amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease), is a fatal neurodegenerative disease that kills motor neurons, leading to paralysis and death. The mechanism of motor neuron degeneration is not understood and the disease is currently incurable. Ten percent of ALS cases are familial and ninety percent are sporadic. Numerous genetic mutations have been identified to cause familial ALS, which include mutations in SOD1, ALS2, VAPB, senataxin, dynactin, angiogenin, TDP-43, FUS, UBQLN2 and c9orf72 genes. By investigating the mechanism whereby these mutants cause neurodegeneration in cellular and animal models, advances have been made in our understanding of the disease mechanism. Recently, by years of genetic studies we have discovered novel mutations in the profilin1 gene that cause ALS. Profilin is an actin-binding protein involved in regulation of actin dynamics and other important cellular signaling processes. Our preliminary experiments in cultured cells suggest that the PFN1 mutants can form intracellular aggregates, dominantly disrupt actin polymerization and growth cone morphology, leading to an inhibition of axon outgrowth. Based on these observations, we hypothesize that mutant profilin 1 cause neurodegeneration by a gain-of-function type of mechanism. To test this hypothesis, we propose to construct and analyze transgenic mice that overexpress mutant and wild type profilin 1. The results will provide evidence either for or against this hypothesis. In addition, if overexpression of mutant profilin 1 causes motor neuron degeneration, this experiment will also generate a new mouse model for ALS, which can be used by the ALS research community to explore the mechanism of motor neuron degeneration and test therapeutic strategies.