ER SIGNAL AND CHAPERONE-MEDIATED AUTOPHAGY IN NEURONAL STRESS

神经元应激中的 ER 信号和伴侣介导的自噬

• 批准号: 8811485
• 负责人: ZIXU MAO
• 金额: $ 34.13万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-15 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8811485
• 关键词: Acute; Alzheimer' s Disease; Attenuated; Autophagocytosis; Calcium; Cell Death Signaling Process; Cell Line; Cell physiology; Cells; Cessation of life; Chronic; Coupling; Critical Pathways; Data; Development; Disease; Endoplasmic Reticulum; Enhancers; Face; Failure; Functional disorder; Genetic Models; Health; Hippocampus (Brain); Homeostasis; Human; In Vitro; Individual; Injury; Knowledge; Laboratories; Lead; Link; Lysosomes; MAP Kinase Gene; MAPK14 gene; Mammalian Cell; Mediating; Mediator of activation protein; Membrane Proteins; Methods; Mitochondria; Mitogen-Activated Protein Kinase Inhibitor; Modeling; Molecular; Molecular Chaperones; Muscle Cells; Names; Nerve Degeneration; Neurodegenerative Disorders; Neuronal Injury; Neurons; Organelles; Outcome; Parkinson Disease; Pathogenesis; Pathologic; Pathway interactions; Play; Population; Process; Proteins; Reaction; Regulation; Regulatory Pathway; Research; Role; Signal Pathway; Signal Transduction; Site; Stress; Stroke; System; Testing; Tissues; base; biological adaptation to stress; brain tissue; coping; design; effective therapy; endoplasmic reticulum stress; human FRAP1 protein; in vivo; innovation; insight; nervous system disorder; neuron loss; neuronal survival; neuroprotection; neurotoxic; neurotoxicity; novel; novel therapeutic intervention; novel therapeutics; pars compacta; protein folding; response; secretory protein; sensor; transcription factor

DESCRIPTION (provided by applicant): Neurons, when faced with endogenous and exogenous insults, mobilize their network of machinery to relief stress. Failure of this attempt often results in neuronal death. Many human neurological diseases such as Alzheimer's and Parkinson's diseases are characterized by the pathological loss of neurons. The long-term objective of our research is to understand how neurons respond to stress and the role of dysfunction of survival response in neurodegenerative process. We propose in this application to study a novel link between endoplasmic reticulum (ER) and lysosomes, two key organelles responsible for handling stress and maintaining cellular homeostasis, in neuronal stress response and in neurodegenerative process. Studies indicate that many toxic signals perturb ER homeostasis. Correcting ER stress requires the activation of multiple ER signal pathways. However, prolonged stress may also direct ER to generate cell death signals. There is strong evidence to implicate the dysfunction of ER stress response in both acute and chronic neurological diseases. Lysosomes participate in maintaining neuronal homeostasis by degrading intracellular constitutes in response to stress, a process named autophagy. Chaperone-mediated autophagy (CMA) is distinct from the traditional macroautophagy in that CMA selectively degrades individual proteins. CMA is critical since nearly 30% of cytosolic proteins contain the conserved motif recognized by CMA and are potential regulatory targets. Recent studies suggest that dysfunction of CMA plays an important role in neuronal stress and neurological diseases. Despite their respective roles in handling neuronal stress, it is not known whether ER stress and CMA are linked. Our recent studies showed that the nonfunctional form of neuronal survival protein, myocyte enhancer factor 2D (MEF2D), is degraded by CMA and disruption of this regulatory process underlies neuronal stress and occurs in models of Parkinson's diseases. Our preliminary studies indicate that ER stress leads to MEF2D degradation, which is dependent on CMA and requires p38 MAPK, a well-known stress sensor. Together, these intriguing data support an exciting hypothesis that ER stress activates CMA via a p38 dependent mechanism. We will combine molecular and cellular methods and use in vivo and genetic models to determine in Aim I, the role of p38 MAPK in ER stress-mediated activation of CMA in neurons; in Aim II, the mechanisms by which p38 senses ER stress and activates CMA; and in Aim III, the role of ER stress-p38-CMA pathway in neuronal viability. This study will establish a novel link between two key processes, ER stress and lysosomal CMA, reveal the stress sensor p38 MAPK as the mediator, uncover the molecular mechanism(s) underlying this regulatory pathway, and establish a functional role for this network in neuronal stress and survival. This new mechanistic network should be highly relevant to the pathogenic process of neurological diseases and may aid the development of novel therapeutic strategies.

描述（由申请人提供）：神经元，当面临内源性和外源性的侮辱，调动他们的网络机制，以缓解压力。这种尝试的失败通常会导致神经元死亡。许多人类神经系统疾病如阿尔茨海默病和帕金森病的特征在于神经元的病理性损失。本研究的长期目标是了解神经元对应激的反应以及生存反应功能障碍在神经退行性变过程中的作用。我们建议在这个应用程序中研究一种新的连接内质网（ER）和溶酶体，两个关键的细胞器负责处理压力和维持细胞内稳态，在神经元应激反应和神经退行性过程。研究表明，许多毒性信号扰乱ER稳态。纠正ER应激需要激活多条ER信号通路。然而，长时间的应激也可能导致ER产生细胞死亡信号。有强有力的证据表明，ER应激反应功能障碍在急性和慢性神经系统疾病。溶酶体通过降解细胞内的物质来维持神经元的稳态，这一过程被称为自噬。分子伴侣介导的自噬（CMA）与传统的大自噬不同，CMA选择性地降解单个蛋白质。CMA是至关重要的，因为近30%的胞质蛋白含有CMA识别的保守基序，并且是潜在的调控靶点。最近的研究表明，CMA功能障碍在神经元应激和神经系统疾病中起重要作用。尽管它们各自在处理神经元应激中的作用，但不知道ER应激和CMA是否相关。我们最近的研究表明，神经元存活蛋白的非功能形式--肌细胞增强因子2D（MEF 2D）会被CMA降解，而这一调节过程的破坏是神经元应激的基础，并发生在帕金森病模型中。我们的初步研究表明，ER应力导致MEF 2D降解，这是依赖于CMA，并需要p38 MAPK，一个众所周知的应力传感器。总之，这些有趣的数据支持了一个令人兴奋的假设，即ER应激通过p38依赖机制激活CMA。我们将结合联合收割机的分子和细胞的方法，并使用在体内和遗传模型，以确定在目的I，在ER应激介导的CMA激活神经元中的作用，在目的II，通过何种机制，p38感应ER应激和激活CMA，并在目的III，ER应激p38-CMA通路在神经元活力的作用。本研究将建立两个关键过程，内质网应激和溶酶体CMA之间的新联系，揭示压力传感器p38 MAPK作为介质，揭示这一调节途径的分子机制，并建立该网络在神经元应激和存活中的功能作用。这种新的机制网络应该与神经系统疾病的致病过程高度相关，并可能有助于开发新的治疗策略。