O-GlcNAc in protein homeostasis in the context of PD, AD and DLB

PD、AD 和 DLB 背景下 O-GlcNAc 在蛋白质稳态中的作用

• 批准号: 10434697
• 负责人: Jianhua Zhang
• 金额: --
• 依托单位: BIRMINGHAM VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10434697
• 关键词: Adolescent; Affect; Aging; Alzheimer' s Disease; Alzheimer' s disease brain; Alzheimer' s disease model; Alzheimer' s disease risk; American; Animal Genetics; Animal Model; Attenuated; Autophagocytosis; Autophagosome; Biology; Brain; Brain Diseases; Chronic; Clinical Trials; Degenerative Disorder; Dementia; Dementia with Lewy Bodies; Development; Diagnosis; Disease; Excision; Foundations; Homeostasis; Human; Impairment; In Vitro; Intervention; Lead; Learning; Light; Link; Lysosomes; Mass Spectrum Analysis; Membrane; Memory; Metabolic; Metabolism; Modification; Molecular; Mus; Mutation; Nerve Degeneration; Nervous System Physiology; Neurodegenerative Disorders; Neurologic; Neurologic Dysfunctions; Neurons; Outcome; Parkinson Disease; Pathogenesis; Pathway interactions; Patients; Pharmacology; Phenotype; Phosphorylation; Post-Translational Protein Processing; Proteins; Proteome; Proteomics; Publications; Rattus; Regulation; Reporting; Research; Role; Site; System; Techniques; Testing; Tissue Model; Toxic effect; Transgenic Mice; Tubulin; Veterans; Work; aged; aging brain; alpha synuclein; cost; design; detection of nutrient; early onset; efficacy evaluation; genetic approach; in vivo; inhibitor; interest; military veteran; mouse model; neurodegenerative phenotype; neuroprotection; neurotoxic; neurotoxicity; novel; novel therapeutics; overexpression; peptide O-linked N-acetylglucosamine-beta-N-acetylglucosaminidase; peptidomimetics; polymerization; preservation; prevent; protein transport; proteostasis; proteotoxicity; success; tau Proteins; tau aggregation; tau phosphorylation; trafficking

It is estimated that approximately 218,000 Veterans were diagnosed with dementia in 2017, and 423,000 new cases of Alzheimer's disease and other dementias among military veterans in the decade ending in 2020. Alzheimer's disease (AD), Dementia with Lewy Bodies (DLB) and Parkinson's disease (PD) are all contributors to dementia which are associated with proteotoxicity; it is then critical to understand the mechanisms through which toxic proteins form and why their removal from neurons is inadequate. The link(s) between proteotoxicity, metabolism and the autophagy pathway, which removes toxic proteins, needs to be understood at a molecular level and in the context of neurodegenerative disease. This proposal focuses on an understudied pathway that is of interest in the sporadic degenerative diseases such as AD. In particular, perturbation of O-GlcNAcylation, as a nutrient sensing pathway, has been demonstrated in human Alzheimer's disease (AD) brains, and inhibition of O-GlcNAcase (OGA) has been shown effective in inhibiting tau phosphorylation in animal models. In light of these putative beneficial effects of increasing O-GlcNAc levels, clinical trials have been initiated to evaluate the efficacy of pharmacologically increasing this post-translational modification in treating AD. Whether the O- GlcNAcylation pathway is tau specific or also engages other neurotoxic proteins, such as α-synuclein, has not been fully investigated in a mammalian system. We are among the first to demonstrate that O-GlcNAcylation is involved in α-synuclein accumulation in vivo in mammalian systems and serves as the principal focus of this proposal. In support of this concept, we have shown that inhibition of OGA increased autophagosomal and α- synuclein accumulation and attenuated autophagic flux in primary neurons. Our recent publication showing that that protein O-GlcNAcylation is increased in PD patients also underlines the growing need to understand the molecular regulation of this pathway. We have already developed the genetic animal models needed to test the overall hypothesis of this proposal that a sustained increase in O-GlcNAc causes α-synuclein accumulation and neurological dysfunction, thereby contributing to the pathogenesis of AD and DLB. We have built a strong research team with expertise in O-GlcNAc biology, cutting-edge techniques in tag-mass spectrometry of the O-GlcNAc modification, autophagy, and mouse models of tissue specific OGA deficiencies and/or with α-synuclein overexpression. This study will: 1) Test the hypotheses that increasing neuronal O- GlcNAc levels disrupts endogenous α-synuclein homeostasis and impairs neurological function, 2) Test the hypothesis that O-GlcNAc modification of α-synuclein as well as autophagy/endolysosomal proteins both contribute to α-synuclein accumulation and thereby contributing to neurodegeneration. The successful completion of these studies will establish a role for O-GlcNAcylation in regulating α-synuclein homeostasis and neurotoxicity, and provide new mechanistic understanding of O-GlcNAc regulation of autophagy, which will guide strategies for neuroprotection. For example, it is conceivable that introducing O-GlcNAcylation site peptide mimetic as competitive inhibitors may be beneficial to prevent detrimental O-GlcNAcylation while preserving beneficial O-GlcNAcylation. Success of this study may bring significant benefit to the Veterans who are affected by these diseases.

据估计，2017 年约有 218,000 名退伍军人被诊断出患有痴呆症，另有 423,000 名新诊断出患有痴呆症。 截至 2020 年的十年里，退伍军人中阿尔茨海默病和其他痴呆症的病例数。 阿尔茨海默氏病 (AD)、路易体痴呆 (DLB) 和帕金森氏病 (PD) 都是促成因素 与蛋白质毒性相关的痴呆症；因此，了解其中的机制至关重要 哪些有毒蛋白质形成以及为什么它们从神经元中去除不充分。蛋白质毒性之间的联系， 新陈代谢和自噬途径（去除有毒蛋白质）需要从分子水平上进行了解 水平和神经退行性疾病的背景下。该提案重点关注一个尚未得到充分研究的途径 人们对 AD 等散发性退行性疾病很感兴趣。特别是 O-GlcNAc 酰化的扰动， 作为一种营养感应途径，已在人类阿尔茨海默病 (AD) 大脑中得到证实，并抑制 O-GlcNAcase (OGA) 在动物模型中已被证明可有效抑制 tau 磷酸化。鉴于 这些假定的增加 O-GlcNAc 水平的有益效果，已经启动临床试验来评估 药理学上增加这种翻译后修饰在治疗 AD 中的功效。是否O- GlcNAc 酰化途径是 tau 特异性的，或者也参与其他神经毒性蛋白，例如 α-突触核蛋白，但尚未发现 在哺乳动物系统中进行了全面研究。我们是最先证明 O-GlcNAcylation 是 参与哺乳动物系统体内 α-突触核蛋白的积累，并作为该研究的主要焦点 提议。为了支持这一概念，我们已经证明抑制 OGA 会增加自噬体和 α- 原代神经元中突触核蛋白的积累和自噬通量的减弱。我们最近的出版物显示 PD 患者中蛋白质 O-GlcNAc 酰化增加也突显了人们越来越需要了解 该途径的分子调控。我们已经开发出了测试所需的遗传动物模型 该提议的总体假设是 O-GlcNAc 的持续增加会导致 α-突触核蛋白 积累和神经功能障碍，从而促进 AD 和 DLB 的发病机制。 我们建立了一支强大的研究团队，拥有 O-GlcNAc 生物学方面的专业知识、标签质量的尖端技术 O-GlcNAc 修饰、自噬和组织特异性 OGA 缺陷小鼠模型的光谱测定 和/或 α-突触核蛋白过度表达。这项研究将： 1) 检验增加神经元 O- 的假设 GlcNAc 水平会破坏内源性 α-突触核蛋白稳态并损害神经功能，2) 测试 假设 O-GlcNAc 修饰 α-突触核蛋白以及自噬/内溶酶体蛋白 促进 α-突触核蛋白积累，从而导致神经退行性变。成功者 这些研究的完成将确定 O-GlcNAcylation 在调节 α-突触核蛋白稳态中的作用 神经毒性，并为 O-GlcNAc 调节自噬提供新的机制理解，这将指导 神经保护策略。例如，可以想象的是，引入O-GlcNAcylation位点肽 作为竞争性抑制剂的模拟物可能有利于防止有害的 O-GlcNAc 酰化，同时保留 有益的 O-GlcNAc 酰化。这项研究的成功可能会给受影响的退伍军人带来重大利益 受到这些疾病的影响。