Deubiquitinase USP19 in TDP-43 pathogenesis.

与RNA结合的核蛋白TDP-43错误定位于细胞质并聚集在 额颞叶变性(FTLD-TDP变异型)、肌萎缩侧索硬化症(ALS)、 50%的晚发性阿尔茨海默病(AD)患者。异常的TDP-43错误定位和 堆积与内质网(ER)应激、突触功能障碍和 认知和运动障碍。而TDP-43经历了不同的翻译后 修饰包括磷酸化、聚ADP-核糖化、氧化、乙酰化、 苏莫化和泛素化，泛素化是周转所需的最后一个关键修饰 TDP-43通过泛素-蛋白酶体系统和自噬-溶酶体途径。TDP-43是 由E3连接酶Parkin、PJA1和Znf179泛素化。然而，去泛素酶的作用 (DUBS)在调节TDP-43的功能、周转、蛋白病变和毒性方面较差 明白了。人类基因组编码约90个双拷贝。泛素特异性多肽酶(USP)是 人类最大的配音家族，由大约50名成员组成。其中，27个以 中枢神经系统。我们对CNS表达的DUBS进行无偏见筛选的结果表明，USP19是一种 主要的TDP-43 DUB，TDP-43稳定性的积极调节器，并有望进一步 学习。具体地说，初步研究表明，USP19，一种在衰老和中老年期间升高的DUB FTLD-TDP患者的大脑，增加TDP-43的稳定性/聚集性并参与 TDP-43诱导内质网应激。 通过利用小鼠模型和人类死后组织以及分子， 细胞生物学，成像，生化，蛋白质组学，电生理学，行为学，病毒， 组织化学和重组蛋白工具包，这项提议将1.验证USP19的作用 在TDP-43发病机制及体内相关表型的研究中，2.确定其机制基础 USP19在TDP-43去泛素化、稳定性、聚集性和转基因生物毒性中的作用 神经元和体外系统。 这些研究的成功完成将决定《美国专利协议》19和 其对人和小鼠TDP-43发病机制的DUB活性。此外，这些结果将提供 内质网应激和内质网中USP19 DUB活性与TDP-43协同作用的新机制 神经毒性。总之，这些研究将使人们能够追求潜在的治疗方向 靶向USP19介导的机制以减轻TDP-43的病理和毒性。

The RNA-binding nuclear protein TDP-43 mislocalizes to the cytoplasm and aggregates in Frontotemporal lobar degeneration (FTLD-TDP variant), Amyotrophic Lateral Sclerosis (ALS), and >50% of late-onset Alzheimer’s disease (AD). Abnormal TDP-43 mislocalization and accumulation is associated with endoplasmic reticulum (ER) stress, synaptic dysfunction, and cognitive and motor impairments. While TDP-43 undergoes different post-translational modifications including phosphorylation, poly ADP-ribosylation, oxidation, acetylation, sumoylation, and ubiquitination, ubiquitination is a final key modification required for the turnover of TDP-43 via the ubiquitin-proteasome system and autophagy-lysosome pathways. TDP-43 is ubiquitinated by E3 ligases Parkin, PJA1, and Znf179. However, the role of deubiquitinases (DUBs) in the regulation of TDP-43 function, turnover, proteinopathy, and toxicity is poorly understood. The human genome encodes ~90 DUBs. Ubiquitin specific peptidases (USPs) are the largest family of DUBs comprising ~50 members in humans. Of these, 27 are expressed in the CNS. Our results from an unbiased screen of CNS-expressed DUBs identified USP19 as a major TDP-43 DUB, a positive regulator of TDP-43 stability, and a promising candidate for further study. Specifically, preliminary studies indicate that USP19, a DUB elevated during aging and in brains of FTLD-TDP patients, acts to increase TDP-43 stability/aggregation and participates in TDP-43-induced ER stress. By taking advantage of mouse models and human postmortem tissues together with molecular, cell biological, imaging, biochemical, proteomics, electrophysiological, behavioral, viral, histochemical, and recombinant protein toolsets, this proposal will 1. validate the role of USP19 in TDP-43 pathogenesis and associated phenotypes vivo, and 2. determine the mechanistic basis of USP19 in TDP-43 deubiquitination, stability, aggregation, and toxicity in genetically modified neurons and in vitro systems. Successful conclusion of these studies will determine the significant contribution of USP19 and its DUB activity to TDP-43 pathogenesis in humans and mice. Moreover, these results will provide novel mechanistic insights to USP19 DUB activity in concert with TDP-43 in ER stress and neurotoxicity. Together, these studies will enable the pursuit of a potential therapeutic direction of targeting USP19-mediated mechanisms to mitigate TDP-43 pathology and toxicity.