Regulation of paraspeckles by STAU1 in neurodegenerative disease

项目总结/摘要 核旁斑的功能是调节mRNA翻译。隐藏在旁斑中的mRNA 而那些没有进入旁斑的细胞可以从细胞核移位， 有效地翻译。现在有越来越多的证据表明，paraspeckles的数量增加， 在神经退行性疾病中，包括阿尔茨海默病（AD）、额颞叶痴呆（FTD）和 肌萎缩侧索硬化症（ALS）。RNA结合蛋白（RBP）在神经退行性疾病中起着重要作用。 疾病，但它们在paraspeckles的功能还不清楚，但我们证实了一个关键的调节作用， 的paraspeckles介导的压力相关的RBP STAU 1。在支持性研究中，我们发现STAU 1 在包括AD、FTD和ALS在内的多种神经退行性疾病中过量， STAU 1与这些疾病相关的各种分子和运动表型得到改善或恢复。相关 对于paraspeckles，STAU 1与反向重复Alu序列（IRAlus）竞争mRNA结合。 paraspeckle核心蛋白p54 nrb和指导mRNA易位到细胞质，用于主动翻译。的 长链非编码RNA（lncRNA）NEAT 1是旁斑形成所必需的，涉及p54 nrb相互作用。在 我们的初步研究发现，NEAT 1在STAU 1缺失的细胞中显著下调。NEAT1 也与TDP-43相互作用，在AD、FTD和ALS中过量。由于NEAT 1和STAU 1都是 在多种神经退行性疾病中过量，我们假设STAU 1丰度的正常化 将NEAT 1恢复到正常水平，从而恢复旁斑功能。STAU 1可能会更好 因为Neat 1缺失的小鼠心脏功能降低，而Neat 1缺失的小鼠心脏功能降低， Stau 1的细胞是可行的，其特征是没有神经变性。我们的建议分为两个具体的 目标。第一个目标将确定NEAT 1水平和旁斑定位以及旁斑大小， 已经编辑以表达突变体ATXN 2的细胞模型中的数量，突变体ATXN 2与STAU 1相互作用， 细胞质相分离的液滴，其特征在于过量的STAU 1。我们还评估了Neat 1 在我们开发的过表达STAU 1的小鼠模型中的丰度和定位。第二个目标 我们在培养的人皮层神经元中表征了旁斑和NEAT 1，重点是TDP-43病理学。 成功证明NEAT 1在以STAU 1过量为特征的疾病中发生改变， 为AD、FTD、ALS和其他具有异常核的疾病提供新的潜在治疗靶点 paraspeckle功能，更深入地了解NEAT 1和STAU 1在神经退行性变 疾病，并将进一步支持STAU 1作为治疗靶点。

Project Summary/Abstract Nuclear paraspeckles function to regulate mRNA translation. mRNAs that are sequestered in paraspeckles are translationally silent while those not entering paraspeckles can translocate from the nucleus where the can effectively be translated. There is now accumulating evidence that paraspeckles are increased in number and size in neurodegenerative diseases, including Alzheimer’s disease (AD), frontotemporal dementia (FTD), and amyotrophic lateral sclerosis (ALS). RNA-binding proteins (RBPs) have a central role in neurodegenerative disease, but their functions in paraspeckles are not well understood, yet we confirmed a critical regulatory role of paraspeckles mediated by the stress-related RBP STAU1. In supporting studies, we discovered that STAU1 is overabundant in multiple neurodegenerative diseases including AD, FTD, and ALS, and that by normalizing STAU1 various molecular and motor phenotypes relevant to these diseases are improved or restored. Relevant to paraspeckles, STAU1 competes for mRNA binding at inverted repeat Alu sequences (IRAlus) with the paraspeckle core protein p54nrb and directs mRNA translocation to the cytoplasm, for active translation. The long noncoding RNA (lncRNA) NEAT1 is indispensable for paraspeckle formation, involving p54nrb interaction. In our preliminary studies we found that NEAT1 is strikingly downregulated in cells depleted of STAU1. NEAT1 also interacts with TDP-43 and is overabundant in AD, FTD, and ALS. Since both NEAT1 and STAU1 are overabundant in multiple neurodegenerative diseases, we hypothesize that normalization of STAU1 abundance will restore NEAT1 to normal levels, thereby restoring paraspeckle function. STAU1 will likely be a better therapeutic target than NEAT1 itself, because mice null for Neat1 have reduced cardiac function while mice null for Stau1 are viable and are characterized by no neurodegeneration. Our proposal is divided into two specific aims. The first aim will determine NEAT1 levels and paraspeckle localization as well as paraspeckle sizes and numbers in cell models that have been edited to express mutant ATXN2, that interacts with STAU1 in cytoplasmic phase-separated liquid droplets characterized by overabundant STAU1. We also evaluate Neat1 abundance and localization in a mouse model that we developed that overexpresses STAU1. In the second aim we characterize paraspeckles and NEAT1 in cultured human cortical neurons, with focus on TDP-43 pathology. The successful demonstration that NEAT1 is altered in diseases characterized by STAU1 overabundance will lead to new potential therapeutic targets for AD, FTD, ALS and other disorders with abnormal nuclear paraspeckle function, deeper understanding on the significance of NEAT1 and STAU1 to neurodegenerative disease, and will further support STAU1 as a therapeutic target.