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

• 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
• 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' s Disease; Alzheimer' s disease brain; Alzheimer' s disease model; Alzheimer' s disease pathology; Alzheimer' 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

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）清除细胞中的错误折叠蛋白和受损细胞器。 因此，它们的功能对于长寿细胞（例如神经元）特别重要。 ALP中的功能障碍是 与阿尔茨海默氏病（AD）的各个阶段有关。这包括强大的积累 自噬小体和溶酶体样细胞器，围绕细胞外Aβ沉积物（淀粉样蛋白）的肌营养不良轴突 斑块），这是在人类阿尔茨海默氏病脑组织中观察到的标志性病理特征和 在阿尔茨海默氏病的转基因小鼠模型中概括。淀粉样菌斑的形成直接 通过分泌酶的淀粉样前体蛋白（APP）的异常/淀粉样蛋白蛋白水解加工链接。 但是，是否有这些蛋白质货物的这些细胞器的异常运输和积累 在阿尔茨海默氏病中触发了这一关键的致病事件，尚未实验解决。此外， 有关调节轴突中ALP的机理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会实现治疗调制 神经元ALP可减少阿尔茨海默氏病中淀粉样蛋白斑块和有毒Aβ肽的产生。对此 最后，我们提议的研究试图了解a）适配器复合物AP-4如何调节轴突 自噬体和溶酶体生物发生，成熟和转运； b）AP-4的损失如何促进淀粉样蛋白 体内斑块形成，并有可能识别新的AP-4货物，以促进最佳逆行轴突 溶酶体转运，APOE代谢和突触活动。这些拟议的研究的中心是我们的 AP-4损失导致ALP细胞器中异常积累的初步数据提醒 AD病理学的构建，包括堆积应用蛋白质BACE1和PSEN2。这个和我们的初步数据 证明AD小鼠大脑中的AP-4水平降低，额外额外的AP-4损失 甚至野生型小鼠的皮质使我们假设AP-4依赖性轴突自噬体和溶酶体 成熟和运输可保护神经元免受淀粉样蛋白生成的应用程序处理，因此免受淀粉样蛋白 发展。此外，我们在轴突肿胀中也使用超分辨率显微镜在ALP细胞器上的使用 由于孤立的轴突和细胞器上的蛋白质组学在失去AP-4复合物时将产生新颖的见解 在这些病理条件下积累的ALP中间体及其对建筑的相对贡献 在应用程序处理机械上。我们提出的努力剖析AP-4介导的轴突ALP运输和 成熟也可能导致新的治疗机会，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的新见解 我们的研究揭示的溶酶体途径可能与其他神经退行性具有更广泛的相关性 具有溶酶体成分的疾病，例如帕金森氏病，遗传痉挛 截瘫和额叶痴呆症。