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Investigating Neuromelanin-Mediated Locus Coeruleus Neurodegeneration in a Novel Mouse Model of Parkinson's Disease

在帕金森病的新型小鼠模型中研究神经黑色素介导的蓝斑神经变性

基本信息

批准号：
10541704
负责人：
Alexa Faith Iannitelli
金额：
$ 4.56万
依托单位：
EMORY UNIVERSITY
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：
2022-07-01 至 2023-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10541704
关键词：
Address Affect Affinity Chromatography Age Aging American Anxiety Astrocytes Autopsy Behavioral Behavioral Paradigm Binding Bradykinesia Brain Catecholamines Cell Nucleus Cells Chelation Therapy Cicatrix Communities Cytoplasm Cytoplasmic Granules Data Development Diagnosis Disease Electron Microscopy Enzymes Family Fellowship Functional disorder Genes Genetic Transcription Glean Hair Heavy Metals Human Immunohistochemistry Impaired cognition Incidence Individual Injections Intervention Levodopa Life Experience Lipids Longevity Macaca mulatta Mediating Melanins Membrane Mental Depression Messenger RNA Metals Methods Microscopy Molecular Molecular Profiling Molecular Target Monophenol Monooxygenase Motor Mus Nerve Degeneration Neurobiology Neurodegenerative Disorders Neuroimmune Neurons Neurosciences Neurotoxins Parkinson Disease Pathologic Pathology Pathway interactions Patients Peripheral Pharmacology Pharmacotherapy Phase Phenotype Pigments Play Population Postdoctoral Fellow Prevention Primates Production Public Health Quality of life RNA analysis Research Ribosomes Rodent Role Skin Sleep disturbances Structure Study models Substantia nigra structure Symptoms Technical Expertise Techniques Testing Time Tissues Toxic effect Toxin Training Transcript Transgenic Mice Translating Tremor United States Viral Viral Vector Work aged alpha synuclein anxiety-like behavior associated symptom behavioral impairment differential expression dopaminergic neuron eumelanin experience experimental study improved in vivo innovation insight locus ceruleus structure motor deficit motor symptom mouse model neuroinflammation neuromelanin neuropathology non-motor symptom nonhuman primate noradrenergic norepinephrine system novel novel strategies pheomelanin prevent response skills therapeutic target therapeutically effective transcriptome sequencing

项目摘要

Investigating neuromelanin-mediated locus coeruleus neurodegeneration in a novel mouse model of Parkinson’s disease Alexa Iannitelli Summary Parkinson’s disease (PD) is the second most common neurodegenerative disorder worldwide, and is characterized by motor and non-motor symptoms. The leading pharmacotherapy, levodopa, is only effective for treating the motor symptoms caused by dopamine (DA) neuron degeneration, while non-motor symptoms associated with noradrenergic dysfunction have grave consequences for the quality of life experienced by PD patients and are not alleviated by any currently available therapies. Thus, new research on PD neuropathology and treatment must consider the locus coeruleus (LC), the major central noradrenergic nucleus. The LC develops alpha-synuclein pathology prior to DA neurons in PD and is almost completely degenerated in later stage disease, but the molecular mechanisms responsible for its vulnerability are unknown. Along with substantia nigra DA neurons, the LC is the only structure in the brain that produces appreciable amounts of neuromelanin (NM), a dark brown cytoplasmic pigment. It has been proposed that these NM granules initially play a protective role by sequestering toxic catecholamine metabolites and heavy metals, but become harmful during aging and particularly in PD as they overwhelm cellular machinery and get released during neurodegeneration. Because rodents do not naturally produce NM, the study of this pigment has been mostly limited to human postmortem studies, and it has not been possible to experimentally address the role of NM in PD-associated LC pathology. However, I have adapted a viral-mediated approach for expression of human tyrosinase, the enzyme responsible for the development of melanin in skin cells, to promote NM production in rodent LC neurons. I found that pigment expression in the LC recapitulates key features of endogenous NM found in primates, including eumelanin and pheomelanin, lipid droplets, and a double-membrane encasement. By 10-weeks post-injection, mice display severe LC neurodegeneration and a robust neuroinflammatory response, resulting in astrocytic glial scarring. Behavioral consequences include hyperarousal, increased anxiety-like behavior, and cognitive impairment. These phenotypes reflect non-motor symptoms of PD, validating the utility of this model for studying the consequences of NM accumulation in the LC as it relates to neurodegenerative disease. During the F99 phase, I propose to expand these findings by employing the ribo-tagging technique Translating Ribosome Affinity Purification (TRAP) to investigate how changes in gene transcription relate to, and potentially underlie, NM-induced LC dysfunction and degeneration. In the K00 phase, I will apply the information gleaned from these studies to investigate potential mechanistic and pharmacological interventions in the hopes of mitigating toxic NM accumulation and subsequent neurodegeneration, in both the LC and SN. These studies will provide a comprehensive understanding of how NM contributes to the early vulnerability of catecholamine neurons in PD, and will help identify potential molecular targets for the prevention and treatment of this debilitating neurodegenerative disease.

在帕金森病的新型小鼠模型中研究神经黑色素介导的蓝斑神经变性亚历克萨·扬尼泰利概括帕金森病 (PD) 是全球第二常见的神经退行性疾病，其特征是运动障碍和非运动症状。主要的药物疗法左旋多巴仅对治疗引起的运动症状有效多巴胺（DA）神经元变性，而与去甲肾上腺素能功能障碍相关的非运动症状有严重的帕金森病患者的生活质量受到影响，并且目前任何可用的疗法都无法缓解。因此，关于帕金森病神经病理学和治疗的新研究必须考虑蓝斑（LC），它是主要的中枢神经系统。去甲肾上腺素能核。在 PD 中，LC 在 DA 神经元之前出现 α-突触核蛋白病理，并且几乎完全在疾病后期退化，但导致其脆弱性的分子机制尚不清楚。连同黑质 DA 神经元，LC 是大脑中唯一产生大量神经黑色素的结构 (NM)，一种深棕色细胞质色素。有人提出，这些 NM 颗粒最初通过以下方式发挥保护作用：隔离有毒的儿茶酚胺代谢物和重金属，但在衰老过程中变得有害，特别是在帕金森病中它们压垮细胞机器并在神经退行性变过程中被释放。因为啮齿类动物不会自然产生 NM，对这种色素的研究主要局限于人类尸检研究，而且还不可能通过实验探讨 NM 在 PD 相关 LC 病理学中的作用。然而，我采用了病毒介导的方法用于表达人酪氨酸酶（这种酶负责皮肤细胞中黑色素的形成），以促进 NM 啮齿动物 LC 神经元的产生。我发现 LC 中的色素表达概括了内源性 NM 的关键特征在灵长类动物中发现，包括真黑素和褐黑素、脂滴和双层膜包裹。 10周后注射后，小鼠表现出严重的 LC 神经变性和强烈的神经炎症反应，导致星形胶质细胞胶质疤痕。行为后果包括过度警觉、焦虑样行为增加和认知障碍。这些表型反映了 PD 的非运动症状，验证了该模型在研究 PD 后果方面的实用性 NM 在 LC 中的积累与神经退行性疾病有关。在F99阶段，我建议扩展这些通过采用核糖标记技术翻译核糖体亲和纯化 (TRAP) 来研究如何基因转录的变化与 NM 诱导的 LC 功能障碍和变性有关，并且可能是其基础。在K00 阶段，我将应用从这些研究中收集的信息来研究潜在的机制和药理学干预措施希望减轻 LC 和 SN 中有毒 NM 的积累和随后的神经退行性变。这些研究将提供对 NM 如何促进早期脆弱性的全面理解。儿茶酚胺神经元，将有助于确定预防和治疗这种疾病的潜在分子靶点使人衰弱的神经退行性疾病。