Chronic alcohol-induced mitochondrial oxidant stress and Alzheimer's related pathogenesis

项目总结 酒精是最常见的滥用物质，阿尔茨海默病(AD)是最常见的 神经退行性疾病。酗酒是阿尔茨海默病发展的一个重要风险因素 酒精滥用和阿尔茨海默病的交集给公众健康带来了巨大的担忧。长期大量饮酒 与患阿尔茨海默病的风险更高和疾病加速进展有关。临床部 AD阶段之前有一个长达数十年的临床前阶段，其特征是早期沉积 淀粉样蛋白b(Ab)和蓝斑(LC)的神经元丢失，蓝斑是脑干中的去甲肾上腺素核。我们 提出了一种新的机制，即慢性饮酒使LC神经元易受 退化。我们最近发现了一种新的细胞机制，它选择性地诱导线粒体 轴突中的氧化应激。胞液中的单胺，包括去甲肾上腺素，是由单胺代谢的 氧化酶(MAO)酶和这个过程中产生的电子直接穿梭到 线粒体膜间间隙。这会选择性地增加线粒体氧化应激。 轴突。我们认为长期饮酒激活了轴突线粒体的这一新机制。 氧化应激导致LC神经元退行性变。我们的初步研究表明，慢性、 间歇性饮酒使LC中VMAT2基因表达减少，轴突氧化应激增加。 重要的是，我们还表明，在APP/PS1小鼠中，慢性、 间歇性饮酒与年龄匹配的喝水小鼠的比较。因此，我们假设 慢性间歇性饮酒降低LC中VMAT2的表达，导致升高 MAO对胞质去甲肾上腺素的代谢，进而导致轴突线粒体氧化应激。这 线粒体氧化应激升高可加速小鼠LC变性和抗体沉积 AD的模型。我们将使用两种AD遗传小鼠模型、APP/PS1和APP-NL敲打-来验证这一假说。 在小鼠中，发展为进行性抗体病理。一种尖端双光子激光扫描的组合 体外脑片显微镜(2PLSM)，假性荧光神经递质(FFN)，基因编码 将使用氧化还原生物传感器、免疫组织化学、体视学、药理学和遗传学技术。 探讨慢性间歇性饮酒对VMAT2表达的影响 去甲肾上腺素的包装，LC轴突线粒体氧化应激，LC变性，抗体病理学，以及 对毛的依赖。在目标1中，我们将确定慢性间歇性饮酒对LC的影响 轴突线粒体氧化应激。在目标2中，我们将确定长期饮酒对 LC退行性变与抗体病理学。我们提出的实验将是探索新的轴突的第一个实验 线粒体氧化应激介导的神经退行性变机制 长期饮酒和阿尔茨海默病。

PROJECT SUMMARY Alcohol is the most commonly abused substance and Alzheimer’s disease (AD) is the most common neurodegenerative disease. Alcohol abuse is a significant risk factor for the development of AD and this intersection of alcohol abuse and AD presents an enormous public health concern. Chronic, heavy alcohol use is associated with a higher risk of developing AD and accelerated progression of the disease. The clinical phase of AD is preceded by a decades long preclinical phase that is characterized by early deposition of amyloid b (Ab) and neuronal loss in the locus coeruleus (LC), a norepinephrine nucleus in the brainstem. We propose a novel mechanism by which chronic alcohol consumption renders LC neurons vulnerable to degeneration. We recently discovered a novel cellular mechanism that selectively induces mitochondrial oxidant stress in axons. Cytosolic monoamines, including norepinephrine, are metabolized by monoamine oxidase (MAO) enzymes and the electrons generated from this process are directly shuttled into the mitochondrial intermembrane space. This produces increased mitochondrial oxidant stress selectively in axons. We propose that chronic alcohol consumption activates this novel mechanism of axonal mitochondrial oxidant stress leading to a degenerative cascade in LC neurons. Our pilot studies suggest that chronic, intermittent alcohol consumption decreased VMAT2 mRNA and increased axonal oxidant stress in the LC. Importantly, we also showed that Ab pathology was increased in APP/PS1 mice that underwent chronic, intermittent alcohol consumption compared to age-matched water drinking mice. Thus, we hypothesize that chronic, intermittent alcohol consumption decreases VMAT2 expression in the LC leading to increased metabolism of cytosolic norepinephrine by MAO, which then causes axonal mitochondrial oxidant stress. This elevated mitochondrial oxidant stress would then accelerate LC degeneration and Ab deposition in mouse models of AD. We will test this hypothesis using 2 genetic mouse models of AD, APP/PS1 and APP-NL knock- in mice, which develop progressive Ab pathology. A combination of cutting-edge two-photon laser scanning microscopy (2PLSM) in ex vivo brain slices, false fluorescent neurotransmitters (FFNs), genetically encoded redox biosensors, immunohistochemistry, stereological, pharmacological, and genetic techniques will be used to investigate the effects of chronic, intermittent alcohol consumption on VMAT2 expression, VMAT2 packaging of norepinephrine, LC axonal mitochondrial oxidant stress, LC degeneration, Ab pathology, and MAO-dependence. In aim 1, we will determine the effect of chronic, intermittent alcohol consumption on LC axonal mitochondrial oxidant stress. In aim 2, we will determine the effect of chronic alcohol consumption on LC degeneration and Ab pathology. Our proposed experiments will be the first to explore a novel axonal mitochondrial oxidant stress-mediated neurodegenerative mechanism underlying the interaction between chronic alcohol consumption and AD.