Estradiol reduces mitochondrial oxidant stress in SNc DA neurons

项目摘要 黑质致密部(SNC)多巴胺能神经元选择性丢失是一种 帕金森氏病(PD)的特征。帕金森病是最常见的神经退行性变 运动障碍，并优先影响男性，他们患帕金森病的风险增加两倍 与女性相比。在人类和帕金森病动物模型中的大量证据表明，雌激素是 对这种降低的风险负责。雌激素如何保护黑质多巴胺神经元尚不清楚。虽然 SNC DA神经元脆弱性的潜在机制尚不完全清楚，线粒体 功能障碍是帕金森病病理的一个明显因素。黑质多巴胺神经元是中枢神经系统的重要调节因子 自愿行动。鉴于自愿迁徙对进化生存的重要性，SNC DA 神经元进化出冗余机制以确保准备好钙、神经递质和三磷酸腺苷 足以维持长时间的释放。Cav1 CA2+渠道通过以下方式帮助建立SNC就绪性 支持起搏，刺激DA合成，并触发线粒体ATP的产生。 此外，有证据表明，多巴胺通过单胺氧化酶(MAO)代谢。 刺激线粒体三磷酸腺苷的产生。虽然这些影响可能会提供短期优势， 持续持续刺激黑质多巴胺神经元线粒体呼吸产生反应性 氧和氮物种，并增加线粒体损伤和周转。我的初选 数据显示雌性小鼠黑质多巴胺轴突线粒体基线氧化减少 与雄鼠相比。这种作用被17β-雌二醇进一步增强，并被 雌激素受体抑制剂，4-羟基他莫昔芬。这一效应有两个潜在的调解人。 首先，雌激素是一种MAO抑制剂。第二，雌激素敏锐而有力地抑制CaV1Ca2+ 频道。根据这些初步数据，我们假设雌激素保护黑质多巴胺神经元 通过两种汇聚机制降低轴突线粒体氧化应激：1)通过 降低MAO活性；2)抑制Cav1钙通道。我们将检验这一假设 双光子激光扫描显微镜在靶向感染动物脑片中的应用 荧光线粒体氧化或钙感受器与STRICAL偶联的表达 药理学。此外，我们将评估17β-雌二醇对生物能量的贡献 对持续释放多巴胺的需求。除了及时和重要地解决这些问题之外 问题，该项目将提供光学、电生理、 药理学和基因技术，当与科学严谨性培训相结合时 苏梅尔博士和伍利博士将推动我走向独立而富有成效的学术生涯。

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.