C. elegans Model for Neurodegenerative Diseases of Aging

描述(由申请人提供)：蛋白质组的稳定性对所有生物合成过程的保真度至关重要，并对细胞的长期健康和生物体的寿命做出重大贡献。虽然错误折叠蛋白的表达是蛋白质生物发生所固有的，但损伤蛋白的积累已越来越被认为是衰老和老年相关疾病的重要贡献者。我们已经证明，应激和衰老反应中受损蛋白质的慢性表达对蛋白质稳态(蛋白质稳态)具有毁灭性的后果，导致几乎所有生物过程都有一系列令人困惑的表型。这项拨款的目的是了解衰老过程中蛋白质平衡失调的基础，以及这些事件如何增加疾病风险。为了解决这个问题，我们将研究疾病相关的、亚稳态的、易于聚集的蛋白在线虫中的表达如何导致蛋白质平衡机制的崩溃，以及有效的细胞保护途径在恢复其平衡方面的作用。这将在三个目标中提出：1。衰老和疾病中蛋白质平衡的遗传学。我们将采用系统的方法来识别调控疾病相关聚集倾向蛋白折叠稳定性的基因网络。这将通过线虫全基因组RNAi筛选来鉴定多聚Q-扩展蛋白(雄激素受体、Aaxin-3、Huntingtin、突变的SOD1、A2和相关的淀粉样蛋白Adan和Abri以及酵母蛋白(Sup35))的蛋白质稳定网络。对这些筛选的比较分析将提供遗传学基础，以确定每种易于聚集的蛋白质的共同和不同特征，以及蛋白质平衡网络的组成如何反映每种蛋白质的折叠稳定性；2.蛋白质平衡在衰老和疾病中的蛋白质组学。衰老和容易聚集的蛋白质的慢性表达干扰了蛋白平衡，这反过来又导致蛋白质损伤的进一步放大，因为其他亚稳态蛋白质错误折叠。我们建议结合细胞生物学和蛋白质组学的方法来确定面对衰老和蛋白毒性应激的危险的不稳定蛋白质组，以及3.蛋白质平衡崩溃的细胞机制。我们的结果表明，受损的非天然蛋白隔离分子伴侣，随着时间的推移，这会导致依赖伴侣的细胞过程的失调。由于伴侣蛋白在细胞浓度以及细胞和组织类型之间的差异，我们认为伴侣蛋白的隔离是导致细胞功能障碍和组织病理的一个因素，并建议了一种恢复年轻蛋白平衡状态的方法。 公共卫生相关性：蛋白质组的稳定性对细胞的健康和生物体的寿命至关重要。蛋白质损伤及其对蛋白质生物发生的影响日益被认为是导致衰老和老年性疾病的重要因素。这项研究是为了确定保护细胞免受错误折叠蛋白质应激的蛋白质平衡网络，确定蛋白质损伤是如何干扰健康的蛋白质平衡和细胞功能的，并激活应激反应通路来恢复蛋白质组。认识到与年龄相关的蛋白质平衡失衡是疾病的一个重要因素，这为疾病管理提供了一种新的方法，将重点放在所有错误折叠和受损的蛋白质共同的早期分子事件上，而不考虑受影响的组织。

DESCRIPTION (provided by applicant): The stability of the proteome is of central importance to the fidelity of all biosynthetic processes, and contributes significantly to the long-term health of the cell and the lifespan of the organism. While the expression of misfolded proteins is intrinsic to protein biogenesis, the accumulation of damaged proteins has become increasingly recognized as a prominent contributor to aging and age-associated disease. We have shown that chronic expression of damaged proteins in response to stress and aging has devastating consequences on protein homeostasis (proteostasis), resulting in a bewildering collection of phenotypes affecting nearly all biological processes. The aims of this grant are to understand the basis of proteostasis dysregulation during aging, and how these events enhance the risk of disease. To address this, we will examine how the expression of disease associated, metastable, aggregation-prone proteins in C. elegans leads to the collapse of the proteostasis machinery, and the role of potent cytoprotective pathways to restore its balance. This will be presented in three aims: 1. The genetics of proteostasis in aging and disease. We will take a systems approach to identify the gene networks that regulate the folding stability of disease associated aggregation-prone proteins. This will be accomplished by genome-wide RNAi screens in C. elegans to identify the proteostasis network for polyQ-expansion proteins (Androgen Receptor, Ataxin-3, Huntingtin, mutant SOD1, A2 and related amyloidogenic proteins ADan and ABri, and yeast prions (Sup35). Comparative analysis of these screens will provide a genetic basis to identify common and distinct features of each aggregation-prone protein and how the composition of the proteostasis network reflects the folding stability of each protein, 2. The proteomics of proteostasis in aging and disease. Aging and chronic expression of aggregation-prone proteins interfere with proteostasis, which in turn leads to a further amplification of protein damage as other metastable proteins misfold. We propose a combination of cell biological and proteomic approaches to identify the unstable proteome that is at risk in the face of aging and proteotoxic stress, and 3. Cellular mechanisms of proteostasis collapse. Our results suggest that damaged non-native proteins sequester molecular chaperones, which over time, results in the dysregulation of chaperone-dependent cellular processes. As chaperones vary in cellular concentration and among cell and tissue types, we propose that chaperone sequestration is a contributing factor to cellular dysfunction and tissue pathology and suggest an approach to restore the youthful proteostatic state. PUBLIC HEALTH RELEVANCE: The stability of the proteome is central to the health of the cell, and lifespan of the organism. Protein damage and its consequence to protein biogenesis are increasingly recognized as a prominent contributor to aging and age-associated disease. The research proposed here is to identify the proteostasis network that protects the cell against the stress of misfolded proteins, establish how protein damage interferes with healthy proteostasis and cellular function, and to activate stress responsive pathways to restore the proteome. The recognition that age-associated imbalance in proteostasis is a prominent contributor to disease offers a new approach for disease management that places a priority on early molecular events common to all misfolded and damaged proteins regardless of the affected tissue.