Estradiol reduces mitochondrial oxidant stress in SNc DA neurons

雌二醇降低 SNc DA 神经元线粒体氧化应激

• 批准号: 9755317
• 负责人: Kristen Stout
• 金额: $ 6.27万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-30 至 2020-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9755317
• 关键词: 4-Hydroxy-Tamoxifen; Achievement; Acute; Address; Affect; Animal Model; Animals; Automobile Driving; Axon; Basal Ganglia; Behavior; Bioenergetics; Brain; Calcium; Cells; Characteristics; Communication; Consumption; Corpus striatum structure; Coupled; Data; Dopamine; Drug Design; Electron Transport; Electrons; Electrophysiology (science); Ensure; Enzymes; Estradiol; Estrogen Receptors; Estrogen Therapy; Estrogens; Ethics; Etiology; Experimental Designs; Female; Genetic; Genetic Techniques; Goals; Gonadal Steroid Hormones; Incidence; Laser Scanning Microscopy; Levodopa; Measures; Mediating; Mediator of activation protein; Metabolism; Methods; Midbrain structure; Mitochondria; Mitochondrial Matrix; Molecular; Monitor; Monoamine Oxidase; Monoamine Oxidase A; Monoamine Oxidase Inhibitors; Movement; Movement Disorders; Mus; Nerve Degeneration; Neurotoxins; Neurotransmitters; Nitrogen; Onset of illness; Optics; Oxidation-Reduction; Oxidative Phosphorylation; Oxidative Stress; Oxygen; Parkinson Disease; Pathology; Periodicity; Pharmacology; Postmenopause; Premature Menopause; Production; Readiness; Recycling; Regulation; Respiration; Risk; Role; Scanning; Science; Signal Transduction; Slice; Stress; Substantia nigra structure; Technical Expertise; Testing; Time; Training; Woman; Work; career; career development; cost; disorder risk; dopaminergic neuron; gain of function; genetic approach; human model; improved; inhibitor/antagonist; insight; male; men; mitochondrial dysfunction; motor symptom; neuroprotection; oxidant stress; oxidation; pars compacta; promoter; response; sensor; sex; tool; two-photon; young adult

Project Summary Selective loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) is a hallmark characteristic of Parkinson's disease (PD). PD is the most common neurodegenerative movement disorder and preferentially affects men, who have two-fold increased risk of PD incidence compared to women. Substantial evidence in humans and animal models of PD suggest estrogen is responsible for this decreased risk. How estrogen protects SNc DA neurons is not clear. Though the mechanisms underlying SNc DA neuron vulnerability are not fully understood, mitochondrial dysfunction is a clear contributor to PD pathology. SNc DA neurons are critical regulators of voluntary movement. Given the importance of voluntary movement to evolutionary survival, SNc DA neurons evolved redundant mechanisms to ensure ready calcium, neurotransmitter, and ATP sufficient to sustain prolonged release. Cav1 ca2+ channels help to establish SNc readiness by supporting pacemaking, stimulating DA synthesis, and triggering mitochondrial ATP production. Additionally, evidence suggests that dopamine metabolism via monoamine oxidase (MAO) stimulates mitochondrial ATP production. While these effects may provide short-term advantage, continual perpetual stimulation of mitochondrial respiration in SNc DA neurons generates reactive oxygen and nitrogen species, and increased mitochondrial damage and turnover. My preliminary data demonstrate that baseline mitochondrial oxidation in SNc DA axons of female mice is reduced compared to male mice. This effect was further increased by 17β-estradiol and eliminated by estrogen receptor inhibitor, 4-hydroxytamoxifen. There are two potential mediators of this effect. First, estrogen is an MAO inhibitor. Second, estrogen acutely and potently inhibits Cav1 ca2+ channels. Given this preliminary data, we hypothesize that estrogen protects SNc DA neurons by lowering axonal mitochondrial oxidant stress through two convergent mechanisms: 1) by diminishing MAO activity and 2) inhibiting Cav1 Ca2+ channels. We will test this hypothesis using two photon laser scanning microscopy in ex vivo brain slices of animals with targeted expression of fluorescent mitochondrial oxidation or calcium sensors coupled with rigorous pharmacology. Additionally, we will assess the contribution of 17β-estradiol to the bioenergetic demands of sustained dopamine release. In addition to addressing these timely and important questions, this project will provide advanced training in optical, electrophysiological, pharmacological, and genetic techniques, which, when coupled with training in scientific rigor from Drs. Surmeier and Woolley, will propel me to an independent and productive academic career.

项目概要 黑质致密部 (SNc) 中多巴胺能 (DA) 神经元的选择性丧失是一种 帕金森病（PD）的标志特征。 PD是最常见的神经退行性疾病 运动障碍，尤其影响男性，他们患 PD 的风险增加两倍 与女性相比。人类和动物帕金森病模型中的大量证据表明雌激素是 造成这种风险降低的原因。雌激素如何保护 SNc DA 神经元尚不清楚。虽然 SNc DA 神经元脆弱性的机制尚不完全清楚，线粒体 功能障碍是 PD 病理学的明显促成因素。 SNc DA 神经元是 自愿运动。鉴于自愿运动对进化生存的重要性，SNc DA 神经元进化出冗余机制来确保钙、神经递质和 ATP 准备就绪 足以维持长时间释放。 Cav1 ca2+ 通道有助于建立 SNc 准备状态 支持起搏、刺激 DA 合成并触发线粒体 ATP 产生。 此外，有证据表明多巴胺通过单胺氧化酶（MAO）代谢 刺激线粒体 ATP 的产生。虽然这些影响可能会带来短期优势， 持续不断地刺激 SNc DA 神经元中的线粒体呼吸会产生反应性 氧和氮物种，并增加线粒体损伤和周转。我的初步 数据表明雌性小鼠 SNc DA 轴突中的基线线粒体氧化减少 与雄性小鼠相比。 17β-雌二醇进一步增强了这种效应，并通过 雌激素受体抑制剂，4-羟基他莫昔芬。这种效应有两个潜在的调节因素。 首先，雌激素是MAO抑制剂。其次，雌激素急剧而有效地抑制 Cav1 ca2+ 渠道。根据这些初步数据，我们假设雌激素可以保护 SNc DA 神经元 通过两种趋同机制降低轴突线粒体氧化应激：1) 降低 MAO 活性和 2) 抑制 Cav1 Ca2+ 通道。我们将检验这个假设 使用两个光子激光扫描显微镜对动物的离体脑切片进行靶向 荧光线粒体氧化或钙传感器的表达加上严格的 药理。此外，我们将评估 17β-雌二醇对生物能的贡献 持续释放多巴胺的需求。除了解决这些及时且重要的问题 问题，该项目将提供光学、电生理学、 药理学和遗传技术，与科学严谨的培训相结合 博士。苏梅尔和伍利将推动我走向独立且富有成效的学术生涯。