TDP-43 and FUS RNA pathways in motor neuron degeneration

描述（由申请人提供）：RNA通路的失调正在成为运动神经元变性的中心特征。肌萎缩性侧索硬化症（ALS）是最常见的人类运动神经元退行性疾病，其结果是致命的，而且无法治愈。大约20%的ALS患者还会发生额颞叶变性（FTLD），其特征是由于神经元变性引起的痴呆，通常伴有泛素化蛋白聚集体（FTDL-U）的存在。最近的研究表明，两种RNA结合蛋白（rbp） TDP-43（或TARDBP）和FUS（或FUS/TLS）的突变导致家族性ALS （FALS）和FTLD-U；在大多数散发性ALS病例和许多FTLD-U （FTLD-TDP）病例中检测到含有TDP-43或TDP-43羧基端（c端）片段的蛋白质聚集体，进一步强调了rbp和RNA失调在神经元变性中的重要作用。TDP43和FUS在运动神经元中的RNA靶点和功能尚不清楚。此外，尚不清楚TDP-43和FUS突变如何导致神经元变性。在这项应用中，我们建议开发新的实验系统和策略来研究TDP-43和FUS在RNA通路中的功能，并剖析TDP-43和FUS患者突变体参与运动神经元变性的发病机制。在Aim 1中，我们将建立和表征胚胎干细胞衍生的运动神经元培养系统，以研究TDP-43和FUS。我们将描述突变体TDP-43和FUS在培养的运动神经元和ALS患者运动神经元中的细胞和分子效应。在Aim 2中，我们将确定人脑和运动神经元中TDP-43和FUS的RNA靶点，并研究TDP-43和FUS患者突变是否导致运动神经元中RNA失调。我们期望我们的研究将导致新的实验系统的发展，并将为运动神经元中TDP-43和FUS的功能以及患者突变在神经元变性中的作用提供关键的见解。我们还预计，这项探索性R21资助申请的结果可能会提供重要的见解，这将指导进一步研究对抗这种致命疾病的治疗策略。

DESCRIPTION (provided by applicant): Dysregulation of RNA pathways is emerging as a central feature of degeneration of motor neurons. Amyotrophic lateral sclerosis (ALS) is the most common human motor neuron degenerative disease with a fatal outcome and without a cure. Approximately 20% of ALS patients also develop Frontotemporal Lobar Degeneration (FTLD), characterized by dementia due to neuronal degeneration and often with the presence of ubiquitinated protein aggregates (FTDL-U). Recent studies have shown that mutations of two RNA Binding Proteins (RBPs) known as TDP-43 (or TARDBP) and FUS (or FUS/TLS) cause familial ALS (FALS) and FTLD-U; and protein aggregates containing TDP-43 or TDP-43 carboxy-terminal (C-terminal) fragments are detected in the majority of sporadic ALS cases and in many cases of FTLD-U (FTLD-TDP), further underscoring the paramount importance of RBPs and of RNA dysregulation in neuronal degeneration. The RNA targets and function of TDP43 and FUS in motor neurons are unknown. Furthermore, it is unknown how mutations of TDP-43 and FUS lead to neuronal degeneration. In this application we propose to develop novel experimental systems and strategies to investigate the function of TDP-43 and FUS in RNA pathways and to dissect pathogenetic mechanisms involved in motor neuron degeneration by TDP-43 and FUS patient mutants. In Aim 1, we will establish and characterize embryonic stem cell derived motor neuron culture systems to investigate TDP-43 and FUS. We will characterize the cellular and molecular effects of mutant TDP-43 and FUS in cultured motor neurons and in the motor neurons of ALS patients. In Aim 2, we will identify RNA target for TDP-43 and FUS in human brain and motor neurons and we will investigate whether TDP-43 and FUS patient mutations result in RNA dysregulation in motor neurons. We expect that our studies will lead to the development of novel experimental systems and will provide critical insights in the function of TDP-43 and FUS in motor neurons and the role of patient mutations in neuronal degeneration. We also anticipate that the outcome of this exploratory R21 grant application may provide important insights that will guide further investigations in therapeutic strategies to combat this lethal disease. PUBLIC HEALTH RELEVANCE: In this application we propose to develop novel experimental systems and strategies to investigate how motor neurons degenerate in ALS, a devastating neurodegenerative disease. We anticipate that our studies may provide important insights that will guide further investigations in therapeutic strategies to combat this lethal disease.