Estradiol reduces mitochondrial oxidant stress in SNc DA neurons

项目摘要 选择性丢失黑质多巴胺能神经元是一种神经病理学改变。 帕金森病（PD）的标志性特征。PD是最常见的神经退行性疾病 运动障碍，并优先影响男性，其PD发病率风险增加两倍 与女性相比。在人类和PD动物模型中的大量证据表明，雌激素是 这是降低风险的原因。雌激素如何保护SNc DA神经元尚不清楚。虽然 SNc DA神经元脆弱性的潜在机制尚未完全了解，线粒体 功能障碍是PD病理学的明确贡献者。SNc DA神经元是多巴胺神经元的关键调节因子。 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，以确保钙、神经递质和ATP 足以维持长期释放。Cav 1 ca 2+通道有助于建立SNc准备， 支持起搏、刺激DA合成和触发线粒体ATP产生。 此外，有证据表明，多巴胺代谢通过单胺氧化酶（MAO） 刺激线粒体ATP的产生。虽然这些影响可能提供短期优势， 持续永久刺激SNc DA神经元中的线粒体呼吸产生反应性 氧和氮物种，并增加线粒体损伤和营业额。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-雌二醇可进一步增强这种效应， 雌激素受体抑制剂，4-羟基他莫昔芬。有两个潜在的媒介物的这种影响。 首先，雌激素是一种MAO抑制剂。第二，雌激素急性和有效地抑制Cav 1 Ca 2 + 渠道根据这些初步数据，我们假设雌激素保护SNc DA神经元 通过两种会聚机制降低轴突线粒体氧化应激：1） 降低MAO活性和2）抑制Cav 1 Ca 2+通道。我们将检验这一假设 使用双光子激光扫描显微镜在具有靶向的动物的离体脑切片中 荧光线粒体氧化或钙传感器的表达与严格的 药理学此外，我们将评估17β-雌二醇对生物能量代谢的贡献。 持续释放多巴胺的需求。除了及时解决这些重要问题外， 问题，该项目将提供光学，电生理， 药理学和遗传技术，当再加上科学严谨性的训练， Drs. Surmeier和Woolley，将推动我独立和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.