Probing organismal proteostasis through the response to intracellular infection

通过对细胞内感染的反应探索机体蛋白质稳态

• 批准号: 9240120
• 负责人: Emily R Troemel
• 金额: $ 31.78万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2020-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9240120
• 关键词: Aging; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Animals; Binding; Biochemical; Budgets; CUL1 gene; Caenorhabditis elegans; Caring; Cells; Complex; Cullin Proteins; Data; Defect; Degenerative Disorder; Degradation Pathway; Disease; F Box Domain; Gene Expression; Genes; Genetic; Genetic Epistasis; Genetic Screening; Genetic Transcription; Goals; Growth; Health; Healthcare; Healthcare Systems; Human; Huntington Disease; Immune response; Infection; Intestines; Lead; Ligase; Maintenance; Mediating; Methods; Microbe; Microsporidia; Molecular; Monitor; Nematoda; Neurodegenerative Disorders; Outcome; Parkinson Disease; Pathway interactions; Patient Care; Patients; Proteasome Inhibition; Proteomics; RNA Viruses; Research; Resistance; Role; Signal Pathway; Source; Stress; Structure; Testing; Tissues; Up-Regulation; Virus; base; improved; innovation; insight; misfolded protein; mutant; novel; novel strategies; novel therapeutics; pathogen; polyglutamine; pressure; protein aggregate; proteostasis; proteotoxicity; response; stressor; transcription factor; ubiquitin ligase; ubiquitin-protein ligase

Project Summary/Abstract Maintenance of protein homeostasis, or proteostasis, is critical for health. Proteostasis is perturbed in several aging-related diseases including neurodegenerative diseases like Alzheimer's, Parkinson's, and Huntington's diseases. Caring for patients with these diseases is consuming an increasing fraction of our health care budget. Strikingly, care for Alzheimer's patients alone is responsible for $226 billion in spending per year, and no treatments are available. Thus, new approaches are needed. One such approach involves leveraging the host/pathogen response to infection with intracellular microbes. Our long-term goal is to dissect the mechanisms by which host cells upregulate proteostasis pathways to cope with the increased burden of intracellular infection and replication. Closing this gap in our understanding will provide new insights about proteostasis, and could provide novel treatments for neurodegenerative diseases. Our central hypothesis is that hosts can sense the effects of intracellular infection and increase proteostasis capacity to cope with this increased burden. The objective here is to determine the mechanisms by which the nematode C. elegans upregulates ubiquitin ligase components in response to infection by a natural intracellular microbe that belongs to the microsporidia phylum. Microsporidia commonly infect all animals including humans, and can replicate to very high levels without causing overt effects on the host, likely due to host compensatory mechanisms. Our recent findings indicate that C. elegans upregulates ubiquitin ligase components in response to diverse intracellular infections including microsporidia and virus (Bakowski et al 2014). In unpublished data we have isolated mutants defective in an F-box-related gene (fbxr-1) that constitutively express these ubiquitin ligase components. fbxr-1 mutants have increased pathogen resistance, as well as greatly enhanced thermotolerance and reduced levels of aggregated proteins, indicating improved proteostasis capacity. We hypothesize that C. elegans increases transcription of Skp-Cullin-F-box (SCF) ubiquitin ligase components in order to target misfolded proteins for ubiquitylation and destruction, increasing tolerance of proteotoxic insults. In Specific Aim 1 we will determine where the Cullin, as well as its upstream negative regulator FBXR-1 act to regulate thermotolerance. We also will perform structure/function analysis on the Cullin to test the hypothesis that it is part of a multi-subunit SCF ubiquitin ligase component. In Specific Aim 2 we will identify these other SCF ligase components using genetic and biochemical approaches. In Specific Aim 3 we will determine where FBXR-1 regulates levels of protein aggregates. In Specific Aim 4 we will perform epistasis and characterize new components of the FBXR-1/Cullin pathway, including a candidate transcription factor. This approach is innovative because it leverages the host response to obligate intracellular infection to understand how proteostasis can be improved. The proposed research is significant because it could lead to new treatments for diseases of compromised proteostasis, such as Alzheimer's disease.

项目总结/摘要 蛋白质稳态的维持对健康至关重要。蛋白质稳态受到干扰， 几种与衰老有关的疾病，包括神经退行性疾病，如阿尔茨海默氏症，帕金森氏症， 亨廷顿氏病。照顾这些疾病的患者正在消耗我们越来越多的时间， 保健预算。引人注目的是，仅老年痴呆症患者的护理就占了2260亿美元的支出， 一年，没有治疗方法。因此，需要新的办法。一种这样的方法涉及 利用宿主/病原体对细胞内微生物感染的反应。我们的长期目标是解剖 宿主细胞上调蛋白质稳态途径以科普增加的蛋白质代谢负荷的机制， 细胞内感染和复制。弥合我们理解上的这一差距将为我们提供新的见解， 蛋白酶抑制，并可为神经退行性疾病提供新的治疗方法。我们的核心假设是 宿主可以感受到细胞内感染的影响，并增加蛋白质稳定能力来科普这种影响。 增加了负担。本文的目的是确定线虫C. elegans 上调泛素连接酶组分，以响应天然细胞内微生物的感染， 微孢子虫门微孢子虫通常感染包括人类在内的所有动物，并且可以复制到 很高的水平，而不会对宿主造成明显的影响，可能是由于宿主的补偿机制。 我们最近的研究结果表明，C。线虫上调泛素连接酶组分 多种细胞内感染，包括微孢子虫和病毒（Bakowski et al 2014）。在未公布的数据中， 具有组成性表达这些泛素的F盒相关基因（fbxr-1）缺陷的分离突变体 连接酶组分。fbxr-1突变体具有增加的病原体抗性，以及大大增强的 耐热性和聚集蛋白水平降低，表明蛋白质抑制能力提高。 我们假设C.线虫增加Skp-Cullin-F-box（SCF）泛素连接酶的转录 为了靶向错误折叠的蛋白质进行泛素化和破坏， 蛋白毒性损伤在具体目标1中，我们将确定Cullin及其上游负 调节因子FBXR-1起调节耐热性的作用。我们还将进行结构/功能分析， Cullin来检验它是多亚基SCF泛素连接酶组分的一部分的假设。具体目标2 我们将使用遗传和生化方法鉴定这些其他SCF连接酶成分。具体目标 我们将确定FBXR-1在哪里调节蛋白质聚集体的水平。在《特定目标4》中， 上位性，并表征FBXR-1/Cullin途径的新组分，包括候选转录 因子这种方法是创新的，因为它利用宿主反应来专性细胞内感染， 了解如何改善蛋白质稳态。这项拟议中的研究意义重大，因为它可能导致 新的治疗蛋白质稳态受损的疾病，如阿尔茨海默氏病。