RNA Granules in Cerebellar Neurodegeneration

据世卫组织估计，神经退行性疾病是一种日益加重的社会和经济负担 到2040年，它们将取代癌症成为第二大死亡原因。在神经退行性 疾病的研究，丰富的途径已经被发现，但他们的直接和主要的相关性， 各种人类疾病难以证实，并且靶向途径仍然很困难。的 拟议的工作将描述脊髓小脑共济失调2型（SCA 2）中的应激颗粒（SGs），SCA 2是一种遗传性共济失调， 影响小脑浦肯野神经元（PN）和小脑中的其它神经元的神经变性疾病， 脑干和大脑。SCA 2的原因是ATXN 2基因中的功能获得性CAG扩增 导致共济失调蛋白-2中的多聚谷氨酰胺（polyQ）扩增。ATXN 2以前被认为具有 mRNA代谢基于其与多种RNA结合蛋白（RBP）的相互作用，包括 A2BP 1/RBFOX 1、DDX 6、PABP 1、TDP-43、FUS。我们现在已经证明突变ATXN 2与 SG蛋白Staufen 1，这种相互作用对SG有特异性影响。施陶芬表达（但不是DDX 6或 PABPC 1）随着ATXN 2突变而增加，我们还确定了特定的下游后果， 这种相互作用对直接与施陶芬相互作用的SG mRNA丰度的影响。建议的目标 研究的目的是从机理上描述为什么Staufen表达随着ATXN 2突变而增加， 表征SCA 2患者成纤维细胞和神经元中SCA 2 SG的蛋白质组和mRNA组成， SCA 2转基因小鼠。通过这项工作确定的SG元素可能在治疗上被利用， 治疗SCA 2。本研究的主要目的是：1）研究ATXN 2突变体对蛋白质的抑制作用 自噬作为施陶芬过表达的原因，并将表征SCA 2 SG的形成速率，半衰期， 和超结构，以及SCA 2 SG转录组使用纯化的SG。 2)我们将进行FISH以定位培养的SCA 2神经元和小脑切片中的SCA 2 SG mRNA。 SCA 2小鼠。3)我们将在SCA 2小鼠中确定SCA 2小鼠运动和神经生理表型 单倍不足的施陶芬，并将记录浦肯野细胞放电频率的同时，成像， TIA 1阳性SG和钙丰度。这将确定是否异常SG贩运/定位 与SCA 2小鼠中异常PC生理学相关，这取决于Staufen表达。拟议工作 将阐明SG在神经退行性变中的作用，并将有助于确定新的途径， SCA 2和其他退行性共济失调的治疗

Neurodegenerative diseases represent an ever-increasing societal and economic burden with WHO estimates indicating that they will replace cancer as the 2nd leading cause of death by 2040. In neurodegenerative disease research, a wealth of pathways has been uncovered, but their direct and primary relevance to the respective human disease has been difficult to prove and targeting of pathways has remained difficult. The proposed work will characterize stress granules (SGs) in spinocerebellar ataxia type 2 (SCA2), a hereditary neurodegenerative disease affecting cerebellar Purkinje neurons (PNs) and other neurons in the cerebellum, brainstem and cerebrum. The cause of SCA2 is a gain-of-function CAG expansion in the ATXN2 gene resulting in an expanded polyglutamine (polyQ) in ataxin-2. ATXN2 was previously known to have functions in mRNA metabolism based on its interactions with multiple RNA binding proteins (RBPs) including A2BP1/RBFOX1, DDX6, PABP1, TDP-43, FUS. We have now demonstrated that mutant ATXN2 interacts with the SG protein Staufen1, and this interaction has specific effects on SGs. Staufen expression (but not DDX6 or PABPC1) is increased with ATXN2 mutation, and we have also identified specific downstream consequences of this interaction on the abundance of SG mRNAs directly interacting Staufen. The objective of the proposed research is to characterize mechanistically why Staufen expression increases with ATXN2 mutation, to characterize the proteomic and mRNA composition of SCA2 SGs in SCA2 patient fibroblasts and neurons and in SCA2 transgenic mice. SG elements that are identified by this work might be exploited therapeutically for treating SCA2. Three specific aims are proposed: 1) We will evaluate mutant ATXN2 inhibition of protein autophagy as a reason for staufen overexpression, and will characterize SCA2 SG rate of formation, half-life, and superstructure using superresolution microscopy, as well as SCA2 SG transcriptomes using purified SGs. 2) We will conduct FISH to localize SCA2 SG mRNAs in cultured SCA2 neurons and in cerebellar slices of SCA2 mice. 3) We will determine SCA2 mouse motor and neurophysiological phenotypes in SCA2 mice haploinsufficient for Staufen, and will record Purkinje cell firing frequencies simultaneously with imaging for TIA1 positive SGs and calcium abundance. This will determine whether abnormal SG trafficking/localization associates with abnormal PC physiology in SCA2 mice, depending on Staufen expression. The proposed work will clarify the role for SGs in neurodegeneration and will aid in the identification of new avenues towards treatments of SCA2 and other degenerative ataxias