Presenilin 1 Modulates Lysosome Function and Tau Degradation

Presenilin 1 调节溶酶体功能和 Tau 降解

• 批准号: 10368913
• 负责人: Carol Ann Deaton
• 金额: $ 5.1万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10368913
• 关键词: Address; Affect; Age of Onset; Aging; Alzheimer' s Disease; Antibodies; Autophagocytosis; Autophagosome; Axon; BODIPY; Binding; Biology; Catalytic Domain; Cathepsins; Cell membrane; Characteristics; Complex; Data; Defect; Degradation Pathway; Dendrites; Endosomes; Event; Exhibits; Functional disorder; Genes; Health; Immunoblotting; Impairment; Knowledge; Light; Lysosomes; Measures; Mediating; Monitor; Multivesicular Body; Mutate; Mutation; Neurobiology; Neurodegenerative Disorders; Neurons; Pathogenicity; Pepstatins; Peptide Hydrolases; Peptides; Play; Presenile Alzheimer Dementia; Process; Production; Proteins; Proton Pump; Rattus; Recycling; Reporting; Role; Supervision; Synaptosomes; Testing; Vesicle; exosome; extracellular; familial Alzheimer disease; gamma secretase; immunocytochemistry; inhibitor/antagonist; innovation; knock-down; live cell imaging; mutant; optogenetics; overexpression; postsynaptic; presenilin-1; proteostasis; secretase; small hairpin RNA; tau Proteins; tau aggregation; tau expression; tau-1; trafficking; vector

A common feature of Alzheimer’s disease (AD), as well as other older age onset neurodegenerative diseases, is the accumulation of misfolded, abnormally modified proteins. In AD, aggregates of tau are a classical hallmark. A significant contributing factor to the formation of these proteinaceous accumulations is dysfunction of the lysosome-dependent degradative pathways. Interestingly, the majority of autosomal dominant familial AD (FAD) cases are caused by mutations in presenilin 1 (PS1), the catalytic subunit of the  secretase complex, which also likely facilitates lysosomal function. However, the role of PS1 in mediating lysosome biology and the clearance of tau has not been fully delineated. Given previous studies and our preliminary data, the UNDERLYING PREMISE of this proposal is that in neurons PS1 plays a fundamental role in regulating the function of lysosomes and, thus, tau turnover. Lysosomes play a key role in maintaining proteostasis as multiple degradative pathways direct their cargos to the lysosome for degradation/recycling. Alterations in the activity or intracellular localization of lysosomes contribute to the pathogenic processes of these neurodegenerative diseases. Given the importance of lysosome function to neuron health, understanding how PS1 impacts lysosome biology is of high importance. CRITICAL KNOWLEDGE GAPS include: how depletion of PS1 in primary neurons impacts lysosome pH, the effects of PS1 depletion on autophagosome-lysosome and endosome-lysosome fusion, the impact of PS1 depletion on tau turnover and how re-acidification of lysosomes in neurons with PS1 depleted affects the PS1-induced lysosomal fusion defects and deficiencies in tau turnover. Considering these critical knowledge gaps the OVERALL HYPOTHESIS is that depletion of PS1 leads to impairment of lysosome function, localization and fusion events, which negatively impact tau clearance. In the context of this overall hypothesis, the specific aims of this proposal are to test the hypotheses: (1) that PS1 plays a role in the acidification, activity, and localization of lysosomes and other degradative vesicles within different neuronal compartments and (2) that vesicle- mediated processing/clearance and intraneuronal localization of tau is impaired by knockdown of PS1. These studies will be carried out using primary rat cortical neuron cultures. Overall this a transformative project that addresses significant gaps in our scientific knowledge. The proposal is innovative in conceptualizing PS1 as a key regulator of lysosome function and thus a significant contributor to proteostasis in general and tau more specifically. Further, technically it is innovative as we will be using an optogenetically driven proton pump to decrease the pH of lysosomes after PS1 knockdown to determine if maintaining an acidified lysosome is sufficient to restore its function. The IMPACT of these studies will be a significant contribution to our understanding of the role of PS1 in regulating tau biology via lysosomal function, thus informing general perspectives of neurobiological degeneration in aging. .

阿尔茨海默病 (AD) 以及其他老年发病的神经退行性疾病的一个共同特征是， 是错误折叠、异常修饰的蛋白质的积累。在 AD 中，tau 蛋白的聚集体是一种经典的 标志。形成这些蛋白质积累的一个重要因素是功能障碍 溶酶体依赖性降解途径。有趣的是，大多数常染色体显性家族遗传 AD (FAD) 病例是由早老素 1 (PS1) 突变引起的，早老素 1 (PS1) 是  分泌酶的催化亚基 复杂，这也可能促进溶酶体功能。然而，PS1 在介导溶酶体中的作用 tau 蛋白的生物学特性和清除机制尚未完全阐明。鉴于之前的研究和我们的初步 数据显示，该提议的基本前提是，在神经元中 PS1 在 调节溶酶体的功能，从而调节 tau 蛋白的周转。溶酶体在维持 蛋白质稳态是多种降解途径将其货物引导至溶酶体进行降解/回收。 溶酶体活性或细胞内定位的改变有助于致病过程 这些神经退行性疾病。鉴于溶酶体功能对神经元健康的重要性， 了解 PS1 如何影响溶酶体生物学非常重要。关键知识差距 包括：初级神经元中 PS1 的耗竭如何影响溶酶体 pH 值、PS1 耗竭对溶酶体 pH 值的影响 自噬体-溶酶体和内体-溶酶体融合，PS1 耗竭对 tau 周转的影响和 PS1 耗尽的神经元中溶酶体的重新酸化如何影响 PS1 诱导的溶酶体融合 tau 蛋白转换的缺陷和不足。考虑到这些关键的知识差距 假设 PS1 的消耗会导致溶酶体功能、定位和融合受损 对 tau 清除产生负面影响的事件。在这一总体假设的背景下，本研究的具体目标 建议测试以下假设：(1) PS1 在酸化、活性和定位中发挥作用 不同神经元区室中的溶酶体和其他降解囊泡以及（2）该囊泡- PS1 的敲低会损害 tau 介导的加工/清除和神经元内定位。这些 研究将使用原代大鼠皮质神经元培养物进行。总的来说，这是一个变革性的项目 解决我们科学知识中的重大差距。该提案的创新之处在于将 PS1 概念化为 溶酶体功能的关键调节因子，因此对一般蛋白质稳态和 tau 蛋白稳定有重要贡献 具体来说。此外，从技术上讲，它是创新的，因为我们将使用光遗传学驱动的质子泵来 PS1 敲低后降低溶酶体的 pH 值，以确定维持酸化溶酶体是否有效 足以恢复其功能。这些研究的影响力将为我们做出重大贡献 了解 PS1 通过溶酶体功能调节 tau 生物学的作用，从而为一般情况提供信息 衰老过程中神经生物学退化的观点。 。