Lysosomal control of plasma membrane -endoplasmic reticulum membrane contacts regulates neuronal excitability

溶酶体控制质膜-内质网膜接触调节神经元兴奋性

• 批准号: 10622184
• 负责人: Eamonn James Dickson
• 金额: $ 26.67万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10622184
• 关键词: Alzheimer' s Disease; Animal Behavior; Attention; Autophagocytosis; Award; Brain; Brain Mapping; Brain region; Calcium; Cell membrane; Cellular Membrane; Cholesterol; Cholesterol Homeostasis; Chronic; Communication; Dementia; Disease; Electrophysiology (science); Elements; Endoplasmic Reticulum; Gatekeeping; Genetic Transcription; Golgi Apparatus; Homeostasis; Instruction; Ion Channel; Knowledge; Lead; Link; Lumen of the Lysosome; Lysosomes; Membrane; Metabolism; Mitochondria; Modeling; Molecular; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Nuclear Pore Complex; Optics; Parkinson Disease; Reporting; Seizures; Shapes; Signal Transduction; Site; Symptoms; System; Testing; Toxic effect; Work; behavior test; cholesterol transporters; cytotoxic; loss of function mutation; lysosome membrane; mitochondrial membrane; mouse model; neuronal excitability; neuropathology; neurotoxic; novel; novel therapeutic intervention; progressive neurodegeneration; superresolution imaging

Project Summary Lysosomes are sophisticated and dynamic cellular signaling centers that control metabolism, gene transcription, calcium (Ca2+) homeostasis, and autophagy. A key mechanism through which lysosomes communicate and receive instruction is via transfer of cholesterol at ER–lysosome membrane contact sites. At these contacts the Niemann Pick C1 cholesterol transporter (NPC1) facilitates the efflux of cholesterol out of the lysosome before it is transferred to the ER for distribution to other cellular membranes. Thus, NPC1 is a key gatekeeper in cholesterol metabolism. Further underscoring its importance, loss of function mutations in NPC1 lead to the progressive neurodegenerative disorder, NPC disease. This fatal condition has no cure and is characterized by the accumulation of cholesterol within lysosome lumen and the progressive neurodegeneration of several brain regions that are accompanied by a host of devastating symptoms including seizures, psychiatric problems, and dementia. Notwithstanding clear neuropathological consequences for cholesterol dysregulation in NPC disease, the molecular mechanism(s) linking loss of NPC1 function to disease neuropathology are unknown. Recently our group has reported that loss of NPC1 function results in (i) neuron hyperexcitability, (ii) reorganization of ER– Lysosome, ER–Golgi, and ER–mitochondrial membrane contact sites, and (iii) induces neurotoxic increases in mitochondrial Ca2+. Despite this crucial information there are critical gaps in our knowledge regarding (1) the consequences of enhanced excitability in NPC disease, (2) how lysosomal cholesterol transport alters the molecular elements and choreography at neuronal ER–plasma membrane (ER–PM) contact sites, and (3) if plasma membrane ion channels or ER–PM junctions can be targeted to reduce mitochondrial toxicity and increase neuron viability in NPC disease. Our central hypothesis is that loss of NPC1 function results in aberrant remodeling of ion channel distribution and function at ER–PM contacts to drive cytotoxic increases in mitochondrial Ca2+ leading to neurodegeneration. To test this hypothesis, we implement a multi-scale approach, including super-resolution imaging, electrophysiology, optical mapping of brain excitability, novel murine models, and animal behavior testing to rigorously investigate the mechanisms by which cholesterol efflux from the lysosome tunes neuron viability. The fundamental importance and ubiquitous expression of the NPC cholesterol transporter means we should pay particular attention to molecular elements and signaling cascades that are modified by its activity. Investigating the relationship between cholesterol homeostasis and ion channel signaling at ER–PM membrane contacts in NPC provides a testable model for examining the interdependence of lysosomal cholesterol and ion channel activity and has broad implications for several fields and other cholesterol- linked diseases such as Alzheimer’s and Parkinson’s.

项目概要 溶酶体是复杂且动态的细胞信号传导中心，控制新陈代谢、基因转录、 钙 (Ca2+) 稳态和自噬是溶酶体交流和传播的关键机制。 接收指令是通过内质网-溶酶体膜接触位点的胆固醇转移来实现的。 Niemann Pick C1 胆固醇转运蛋白 (NPC1) 促进胆固醇从溶酶体中流出 它被转移到内质网并分布到其他细胞膜，因此，NPC1 是细胞膜的关键看门人。 NPC1 的功能突变会导致胆固醇代谢的重要性。 进行性神经退行性疾病，即鼻咽癌，这种致命疾病无法治愈，其特点是 溶酶体腔内胆固醇的积累和一些大脑的进行性神经变性 伴随着一系列毁灭性症状的地区，包括癫痫发作、精神问题和 尽管鼻咽癌疾病中胆固醇失调会产生明显的神经病理学后果， 最近，将 NPC1 功能丧失与疾病神经病理学联系起来的分子机制尚不清楚。 我们小组报告称，NPC1 功能丧失会导致 (i) 神经元过度兴奋，(ii) ER 重组 溶酶体、内质网-高尔基体和内质网-线粒体膜接触位点，以及 (iii) 诱导神经毒性增加 尽管有这些重要信息，但我们在以下方面的知识仍存在严重差距：(1) 鼻咽癌疾病中兴奋性增强的后果，(2) 溶酶体胆固醇转运如何改变 神经 ER-质膜 (ER-PM) 接触位点的分子元件和编排，以及 (3) 如果 可以靶向质膜离子通道或 ER-PM 连接来减少线粒体毒性和 我们的中心假设是 NPC1 功能丧失会导致神经元活力增加。 ER-PM接触处离子通道分布和功能的异常重塑导致细胞毒性增加 线粒体 Ca2+ 导致神经变性 为了检验这一假设，我们实施了一种多尺度方法， 包括超分辨率成像、电生理学、大脑兴奋性光学测绘、新型小鼠模型、 和动物行为测试，以严格研究胆固醇从体内流出的机制 溶酶体调节神经元活力 NPC 胆固醇的根本重要性和普遍表达。 转运蛋白意味着我们应该特别注意分子元件和信号级联 研究胆固醇稳态和离子通道信号传导之间的关系。 NPC 中的 ER-PM 膜接触提供了一个可测试的模型，用于检查 溶酶体胆固醇和离子通道活性，对多个领域和其他胆固醇具有广泛的影响- 阿尔茨海默氏症和帕金森氏症等相关疾病。