Protection by Induction of Ubiquitin-Proteasome Systems

描述（由申请人提供）： 受损的蛋白质及其聚集产物在氧化应激和衰老过程中形成。26 S蛋白酶体可以识别并清除这些受损和未折叠的蛋白质;此外，泛素-蛋白酶体系统功能的降低与年龄相关的退行性疾病的发展有关。我们的假设是，维持或增强泛素-蛋白酶体功能是预防或减轻这些年龄相关疾病的一种新策略。我们的初步研究结果表明，二硫代硫酮，保护免受环境剂的毒性，通过刺激Nrf 2信号通路的下游基因的表达，增加小鼠肝脏中26 S蛋白酶体和泛素化酶的多个亚基的表达。该提议被设计为a）评估在毒物攻击后细胞中诱导的蛋白酶体表达的生理益处，B）确定诱导的蛋白酶体表达的影响和Nrf 2对作为老化模型的年轻和衰老鼠成纤维细胞中受损蛋白质积累的作用，c）表征鼠组织中，特别是脑中蛋白酶体表达的诱导模式和水平，在二硫杂环戊烯硫酮处理之后。增强蛋白酶体诱导的功能效应将首先在培养的细胞中使用鼠胚胎成纤维细胞和神经母细胞瘤细胞进行研究。将在细胞模型中比较蛋白酶体水平、蛋白水解活性、蛋白质周转率和化学激发后受损蛋白质的积累的测量，其中蛋白酶体表达通过药理学干预和通过特定蛋白酶体亚基的分子遗传表达而升高。Nrf 2在这些保护作用中的作用将使用nrf 2破坏或抑制的细胞以及通过比较不同年龄的野生型和nrf 2缺陷小鼠来检查。总的来说，这些研究将探讨增强蛋白酶体表达对外源性有毒化学物质和伴随衰老的退行性过程的可能保护作用。该项目的长期目标是严格评估通过激活Nrf 2信号级联增加泛素-蛋白酶体途径的表达可以预防或延缓人类退行性疾病如阿尔茨海默病，帕金森病和肌萎缩侧索硬化症的进展。

DESCRIPTION (provided by applicant): Damaged proteins and their aggregated products are formed during oxidative stress and aging. 26S proteasomes can recognize and remove these damaged and unfolded proteins; moreover, decreased function of the ubiquitin-proteasome system is associated with the development of age-related degenerative diseases. It is our hypothesis that maintenance or enhancement of ubiquitin-proteasome function is a novel strategy to prevent or attenuate these age-related diseases. Our preliminary results indicate that dithiolethiones, which protect against the toxicities of environmental agents by stimulating expression of the downstream genes of the Nrf2 signaling pathway, increase expression of multiple subunits of 26S proteasomes and ubiquitinating enzymes in mouse liver. This proposal is designed to a) evaluate the physiological benefit of induced proteasome expression in cells following challenge by toxicants, b) determine the impact of inducible proteasome expression and the role of Nrf2 on the accumulation of damaged proteins in young and senescence murine fibroblasts as a model of aging, c) characterize inducible patterns and levels of proteasome expression in murine tissues, especially in the brain, following dithiolethione-treatment. Functional effects of enhanced proteasome induction will be initially investigated in cultured cells using murine embryonic fibroblasts and neuroblastoma cells. Measures of proteasome levels, proteolytic activities, protein turnover rates and accumulation of damaged proteins following chemical challenge will be compared in cell models in which proteasome expression is elevated by pharmacological intervention and through molecular genetic expression of specific proteasome subunits. The role of Nrf2 in these protective effects will be examined using nrf2-disrupted or inhibited cells as well as by comparisons in wild-type and nrf2-deficient mice of different ages. Collectively, these studies will explore the possible protective role of enhanced proteasome expression against exogenous toxic chemicals and degenerative processes that accompany aging. The long-term goal of this project is to rigorously evaluate the concept that increased expression of ubiquitin-proteasomes pathway through activation of the Nrf2 signaling cascade can prevent or retard the progression of human degenerative diseases such as Alzheimer's, Parkinson's disease and amyotrophic lateral sclerosis.