Transgenic models of ALS caused by VAPB mutation

描述(申请人提供)：肌萎缩侧索硬化症(ALS)是一种进行性神经退行性疾病，可导致运动神经元变性、骨骼肌萎缩、瘫痪和死亡。我们的长期目标是了解疾病的机制并开发一种治疗方法。目前，典型肌萎缩侧索硬化症唯一可靠的模型是表达突变SOD1的小鼠。最近，VAMP相关蛋白B(VAPB)基因突变被发现可导致运动神经元变性和ALS。由于VAPB突变导致的ALS的临床症状多种多样，既包括典型病例，也包括非典型病例。然而，所有这些都是成人发病。基于体外数据，关于突变的VAPB诱导ALS的机制的主要假说是突变导致显性负活性。然而，目前还没有活体数据。此外，不排除其他可能性，如主导功能获得和功能丧失。我们建议使用转基因方法来区分这三种可能性，以过表达突变的VAPB，并使用转基因RNAi来沉默小鼠的VAPB。来自这两种方法的综合数据将明确地确定这三种机制中哪一种是正确的。由于我们的转基因构建物被设计为Cre诱导的，这些转基因小鼠未来可以通过与在各种特定细胞(神经元、胶质细胞和小胶质细胞)中表达Cre的小鼠杂交，来研究突变的VAPB在运动神经元和非运动神经元细胞中表达的作用。此外，我们建议在培养细胞中进行补充实验，以剖析VAPB的功能和突变的VAPB的功能变化。这些实验将加深我们对运动神经元变性机制的理解，并建立起ALS成人发病转基因模型的二线，该模型可用于ALS治疗策略的临床前分析。相关性：VAPB基因突变导致肌萎缩侧索硬化症(ALS)，这是一种无法治愈的致命神经退行性疾病。我们建议建立细胞培养和转基因小鼠模型来研究VAPB突变是如何导致神经元变性的。一旦建立，这些模型就可以用于治疗化合物的临床前测试。

DESCRIPTION (provided by applicant): Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that causes motor neuron degeneration, skeletal muscle atrophy, paralysis and death. Our long term objective is to understand the disease mechanism and develop a cure. At present, the only robust model for typical ALS is mice that express mutant SOD1. Recently, a mutation in VAMP associated protein B (VAPB) gene has been identified to cause motor neuron degeneration and ALS. The clinical symptom of ALS as a result of the VAPB mutation is variable and includes both typical and atypical cases. All, however, is adult onset. Based on in vitro data, the predominant hypothesis regarding the mechanism whereby mutant VAPB induces ALS is that the mutation leads to a dominant negative activity. However, no in vivo data is available. In addition, other possibilities, such as dominant gain-of-function and loss-of-function have not been ruled out. We propose to differentiate these three possibilities using transgenic approaches to overexpress the mutant VAPB and to silence the mouse VAPB using transgenic RNAi. The combined data from these two approaches will unequivocally determine which one of these three mechanisms is true. Because our transgenic constructs are designed to be Cre-inducible, these transgenic mice can be used to investigate the roles of mutant VAPB expression in motor neuron and non-motor neuron cells in the future by crossing with mice that express Cre in various specific cells (neurons, glia and microglia). Furthermore, we propose complementary experiments in cultured cells to dissect the function of VAPB and the altered function in mutant VAPB. These experiments will enhance our understanding of mechanisms of motor neuron degeneration and establish a second line of adult onset transgenic model for ALS, which can be used for preclinical analysis of therapeutic strategies for ALS. RELEVANCE: A VAPB gene mutation causes amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease without a cure. We propose to establish cell culture and transgenic mouse models to investigate how the VAPB mutation causes neuronal degeneration. Once established, these models can be used for pre-clinical tests of therapeutic compounds.