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

• 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
• 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

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.

在帕金森病小鼠模型中研究神经黑素介导的蓝斑神经变性 Alexa Iannitelli 总结 帕金森病（Parkinson's disease，PD）是世界范围内第二大常见的神经退行性疾病，其特征在于运动神经系统的损伤。 和非运动症状。主要的药物治疗，左旋多巴，只对治疗运动症状有效， 多巴胺（DA）神经元变性，而非运动症状与去甲肾上腺素能功能障碍有严重的 对PD患者的生活质量造成不良后果，并且目前可用的任何疗法都无法缓解。 因此，PD神经病理学和治疗的新研究必须考虑蓝斑（LC），主要的中枢神经系统， 去甲肾上腺素能核LC在PD中先于DA神经元发展α-突触核蛋白病理，并且几乎完全被破坏。 在疾病后期退化，但其脆弱性的分子机制尚不清楚。沿着 在黑质DA神经元中，LC是脑中唯一产生可观数量的神经黑色素的结构 (NM)深褐色细胞质色素。有人提出，这些NM颗粒最初发挥保护作用， 螯合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PD中， 它们压倒了细胞机制并在神经退化过程中被释放。因为啮齿类动物不会自然产生 NM，这种色素的研究主要局限于人类死后研究，而且不可能 实验性地解决了NM在PD相关LC病理学中的作用。不过，我采用了一种病毒介导的方法 用于表达人酪氨酸酶，该酶负责皮肤细胞中黑色素的发育，以促进NM 在啮齿动物LC神经元中产生。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、脂滴和双膜包裹物。到10周 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 神经胶质疤痕。行为后果包括过度觉醒、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，验证了该模型用于研究以下结果的实用性： LC中的NM积累，因为它与神经退行性疾病有关。在F99阶段，我建议扩大这些 研究结果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，并可能是其基础。在K 00 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，希望减轻毒性NM积累和随后的神经变性，在LC和SN。 这些研究将提供一个全面的了解如何北地中海有助于早期脆弱性， 这将有助于确定预防和治疗帕金森病的潜在分子靶点。 使人衰弱的神经变性疾病