Transcriptional control of proteostasis and aging

项目摘要/摘要： 维持蛋白质组折叠和功能的机制(蛋白稳定)在正常情况下变得无效 衰老，导致神经退行性蛋白质错误折叠疾病的发生和发展--包括 阿尔茨海默氏症。蛋白质平衡通过涉及协调调节的综合过程来维持 蛋白质的合成、折叠和降解对不同的信号作出反应。我们已经确定了同源结构域- 相互作用蛋白激酶(HPK-1)作为衰老和蛋白稳态的关键调节因子。HPK-的本构表达 1，足以延缓衰老，保持蛋白稳定，提高抗应激能力，而HPK-1的缺失则损害 抗逆性，加速衰老和蛋白质组的退化。HPK-1通过热休克发挥作用 转录因子(HSF-1)和雷帕霉素复合体1(TORC1)的靶标。HPK-1拮抗苏莫化作用 HSF-1，推测是为了抑制基因表达。HPK-1通过增加一种独立的 机制：通过限制饮食或TORC1失活来诱导自噬。HPK-1表达本身 在营养或热应激后受到不同机制的调节，这意味着HPK-1可能作为 一种综合的应激反应，以维持蛋白质平衡。值得注意的是，我们还发现HPK-1是 在线虫神经元中维持蛋白稳定，最近的一项研究发现诱导哺乳动物的表达 阿尔茨海默病和肌萎缩侧索硬化症患者受神经变性影响区域的同源基因 硬化症患者，表明诱导的应激反应。我们的假设是，HPK-1可以防止年龄- 通过抑制蛋白质的错误折叠和刺激蛋白质的周转来降低蛋白质的稳定性 伴侣蛋白和自噬的调控基因表达。我们将获得机械论的洞察力 HPK-1如何通过蛋白质组学和蛋白质组学调控HSF-1并影响衰老和蛋白质平衡 CRISPR/Cas9靶向突变。我们将联合应用应激源和激活的HPK-1来 了解HPK-1如何作为维持蛋白质组功能的集成系统的一部分发挥作用。我们利用 遗传、基因组和系统生物学方法探索如何动态调节蛋白质组分 网络保障蛋白质组的正常功能。此外，我们还将使用组织特异性基因 操控以了解这个网络如何在组织中发挥作用。以确定生理后果 关于HPK-1在神经元蛋白稳定和变性中的作用，我们将利用聚谷氨酰胺报告和tau的异构体 在线虫神经元内诱导蛋白毒性。此外，我们将确定Hipk1-3丢失的作用 (HPK-1的哺乳动物同源物)在以减少蛋白毒性为目标的药物干预的背景下 Tau对哺乳动物神经元的影响。通过这项工作，我们将了解HPK-1在衰老过程中的作用 在蛋白质平衡网络的调节中，以及对神经退行性疾病的表现的洞察。

Project Summary/Abstract: The mechanisms that maintain proteome folding and function (proteostasis), become ineffective during normal aging, contributing to the onset and progression of neurodegenerative protein misfolding diseases- including Alzheimer’s Disease. Proteostasis is sustained through integrated processes involving coordinated regulation of protein synthesis, folding, and degradation in response to diverse signals. We have identified the homeodomain- interacting protein kinase (HPK-1) as a key regulator of aging and proteostasis. Constitutive expression of hpk- 1, is sufficient to delay aging, preserve proteostasis, and promote stress resistance, while loss of hpk-1 impairs stress resistance, accelerating aging and the deterioration of the proteome. HPK-1 acts via the heat shock transcription factor (HSF-1), and the target of rapamycin complex 1 (TORC1). HPK-1 antagonizes sumoylation of HSF-1, presumably to repress gene expression. HPK-1 extends longevity by an additional independent mechanism: induction of autophagy via dietary restriction or TORC1 inactivation. HPK-1 expression is itself regulated by distinct mechanisms after nutritional or thermal stress, implying that HPK-1 may function as part of an integrated stress response to maintain proteostasis. Notably, we also have found that hpk-1 is required for maintaining proteostasis in C. elegans neurons, and a recent study found induced expression of a mammalian homolog in regions of the brain affected by neurodegeneration in Alzheimer’s Disease and Amyotrophic Lateral Sclerosis patients, suggesting an induced stress response. Our hypothesis is that HPK-1 prevents the age- associated decline of proteostasis by suppressing protein misfolding and stimulating protein turnover through the regulated gene expression of chaperones and autophagy, respectively. We will gain mechanistic insight into how HPK-1 regulates HSF-1 and affects aging and proteostasis through the use of proteomics and CRISPR/Cas9 targeted mutagenesis. We will apply combinations of stressors and activated HPK-1 to understand how HPK-1 functions as a part of an integrated system to maintain proteome function. We utilize genetic, genomic, and systems biology approaches to explore how dynamic regulation of the proteostatic network safeguards proper function of the proteome. In addition, we will employ tissue-specific gene manipulation to understand how this network acts across tissues. To determine the physiological consequences of hpk-1 on neuronal proteostasis and degeneration we will utilize a polyglutamine reporter and isoforms of tau to induce proteotoxicity within C. elegans neurons. Additionally, we will determine the role of Hipk1-3 loss (mammalian homologs of hpk-1) in the context of pharmacological interventions targeted to reduce proteotoxic effects of tau in mammalian neurons. With this work we will gain understanding of the role of HPK-1 during aging in the regulation of the proteostatic network, and insight into the manifestation of neurodegenerative diseases.