Elucidating the role of Adaptor Protein complex-4 in regulating axonal autophagic and lysosomal pathways

阐明衔接蛋白复合物 4 在调节轴突自噬和溶酶体途径中的作用

基本信息

批准号：
10700082
负责人：
Swetha Gowrishankar
金额：
$ 48.32万
依托单位：
UNIVERSITY OF ILLINOIS AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-15 至 2027-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10700082
关键词：
Abeta synthesis Adaptor Signaling Protein Address Age Alzheimer&apos s Disease Alzheimer&apos s disease brain Alzheimer&apos s disease model Alzheimer&apos s disease pathology Alzheimer&apos s disease risk Amyloid beta-Protein Amyloid beta-Protein Precursor Autophagocytosis Autophagosome Axon Binding Proteins Biogenesis Biology Brain Cells Cellular biology Complex Coupled Data Defect Deposition Development Disease Dynein ATPase Event Exhibits Frontotemporal Dementia Functional disorder Genes Genetic Genotype Hereditary Spastic Paraplegia Homeostasis Human Image Immunofluorescence Immunologic Immunoprecipitation Impairment Induced pluripotent stem cell derived neurons Knockout Mice Knowledge Link Lysosomes Mediating Membrane Proteins Metabolism Mission Modeling Molecular Mus Neurodegenerative Disorders Neurons Organelles Outcome Parkinson Disease Pathogenesis Pathogenicity Pathologic Pathology Pathway interactions Pattern Peptides Phenocopy Prefrontal Cortex Process Production Proteins Proteolytic Processing Proteomics Public Health Reelin Signaling Pathway Research Role Senile Plaques Site Sorting Swelling Synapses Techniques Testing Therapeutic Therapeutic Intervention Transgenic Mice Vesicle Wild Type Mouse Work age related age related neurodegeneration amyloid precursor protein processing beta-site APP cleaving enzyme 1 brain tissue cell type experimental study extracellular in vivo induced pluripotent stem cell insight interdisciplinary approach loss of function misfolded protein mouse model novel novel therapeutics presenilin-2 protein complex secretase sortilin superresolution microscopy therapeutic development therapeutically effective tool trafficking trans-Golgi Network

项目摘要

The autophagic and lysosomal pathways (ALP) clear misfolded proteins and damaged organelles from cells. Their function is therefore particularly critical for long-lived cells such as neurons. Dysfunction in the ALP is associated with various stages of Alzheimer’s disease (AD). This includes the robust accumulation of autophagosomes and lysosome-like organelles in dystrophic axons around extracellular Aβ deposits (Amyloid plaques), which are hallmark pathological features observed in human Alzheimer’s disease brain tissue and recapitulated in transgenic mouse models of Alzheimer’s disease. Amyloid plaque formation has been directly linked to aberrant/amyloidogenic proteolytic processing of amyloid precursor protein (APP) by secretases. However, whether abnormal trafficking and accumulation of these organelles bearing these protein cargoes trigger this critical pathogenic event in Alzheimer’s disease, has not been experimentally addressed. In addition, information on mechanisms and specific molecular components regulating ALP in axons remains limited. Elucidating these mechanisms and identifying molecular components might enable therapeutic modulation of neuronal ALP to reduce amyloid plaque burden and toxic Aβ peptide production in Alzheimer’s disease. To this end, our proposed research seeks to understand a) how the adaptor complex, AP-4, regulates axonal autophagosome and lysosome biogenesis, maturation, and transport; b) how loss of AP-4 contributes to amyloid plaque formation in vivo as well as potentially identify new AP-4 cargo that facilitate optimal retrograde axonal lysosome transport, APOE metabolism, and synaptic activity. Central to these proposed studies is our preliminary data that AP-4 loss causes abnormal accumulation of ALP organelles in axonal swellings reminiscent of AD pathology, including build-up of APP cleaving proteins BACE1 and PSEN2. This and our preliminary data demonstrating reduced AP-4 levels in AD mouse brain and an age-dependent loss of AP-4 in the pre-frontal cortex of even wild type mice lead us to hypothesize that AP-4-dependent axonal autophagosome and lysosome maturation and transport protects neurons from amyloidogenic APP processing and thus, from amyloid plaque development. Additionally, our use of super-resolution microscopy on ALP organelles in axonal swellings as well as proteomics on isolated axons and organelles upon loss of AP-4 complex, will yield novel insight into the kinds of ALP intermediates accumulating under these pathological conditions and their relative contributions to build- up of APP processing machinery. Our proposed efforts to dissect out AP-4 mediated axonal ALP transport and maturation could also lead to new therapeutic opportunities that focus on mobilizing these axonal ALP organelles to limit Aβ production and axonal pathology. Furthermore, new insights into cell biology of neuronal autophagic and lysosomal pathways revealed by our studies could have broader relevance to other neurodegenerative diseases that have a lysosome component to their pathology such as Parkinson’s disease, Hereditary Spastic Paraplegia, and fronto-temporal dementia.

自噬和溶酶体途径 (ALP) 可清除细胞中错误折叠的蛋白质和受损的细胞器。因此，它们的功能对于长寿细胞（例如神经元）尤其重要。与阿尔茨海默病 (AD) 的各个阶段相关，其中包括大量积累。细胞外 Aβ 沉积物周围营养不良的轴突中的自噬体和溶酶体样细胞器（淀粉样蛋白斑块），这是在人类阿尔茨海默病脑组织中观察到的标志性病理特征，在阿尔茨海默病的转基因小鼠模型中，淀粉样蛋白斑块的形成已被直接重现。与分泌酶对淀粉样前体蛋白 (APP) 的异常/淀粉样蛋白水解加工有关。然而，携带这些蛋白质货物的这些细胞器是否异常运输和积累引发阿尔茨海默病的这一关键致病事件尚未通过实验解决。关于调节轴突中 ALP 的机制和特定分子成分的信息仍然有限。阐明这些机制并识别分子成分可能有助于治疗调节神经元 ALP 可以减少阿尔茨海默病中淀粉样斑块的负担和有毒 Aβ 肽的产生。最后，我们提出的研究旨在了解 a) 适配器复合体 AP-4 如何调节轴突自噬体和溶酶体的生物发生、成熟和运输 b) AP-4 的损失如何导致淀粉样蛋白体内斑块形成以及潜在地识别新的 AP-4 货物，促进最佳逆行轴突溶酶体转运、APOE 代谢和突触活动是我们这些拟议研究的核心。 AP-4 缺失导致 ALP 细胞器在轴突肿胀中异常积累的初步数据让人想起 AD 病理学，包括 APP 裂解蛋白 BACE1 和 PSEN2 的构建，以及我们的初步数据。证明 AD 小鼠大脑中 AP-4 水平降低以及前额叶中 AP-4 的年龄依赖性损失即使是野生型小鼠的皮层，我们也能捕获 AP-4 依赖性轴突自噬体和溶酶体成熟和运输保护神经元免受淀粉样蛋白生成 APP 处理，从而免受淀粉样斑块的影响此外，我们还使用超分辨率显微镜观察轴突肿胀中的 ALP 细胞器。作为 AP-4 复合物丢失后分离的轴突和细胞器的蛋白质组学，将产生对这些类型的新见解在这些病理条件下积累的 ALP 中间体及其对构建的相对贡献我们建议努力剖析 AP-4 介导的轴突 ALP 运输和成熟还可能带来新的治疗机会，重点是动员这些轴突 ALP 细胞器限制 Aβ 产生和轴突病理学此外，对神经元自噬的细胞生物学有了新的见解。我们的研究揭示的溶酶体途径可能与其他神经退行性疾病具有更广泛的相关性其病理学具有溶酶体成分的疾病，例如帕金森病、遗传性痉挛截瘫和额颞叶痴呆。