Project 2 Title: The brain brush border and microglial activation in response to ethanol

摘要 在发育期或成年期接触酒精可能会导致大脑损伤。酗酒 消费在美国是一个日益严重的问题，特别是在青少年和年轻人中， 正在继续发展，因此更容易受到酗酒对大脑功能的有害影响。 临床和临床前证据都表明，小胶质细胞--大脑的常驻免疫细胞--在这一过程中起着关键作用。 调节酒精引起的神经毒性事实上，酗酒后的脑部炎症会损害大脑 发展和功能。此外，小胶质细胞的激活促进了小鼠模型的饮酒偏好。 慢性酒精暴露然而，小胶质细胞介导的细胞或分子机制， 成年人或青少年大脑中对酒精的反应导致神经元损伤和动物行为改变， 被识别。此外，酒精对小胶质细胞-神经元相互作用在结构或功能上的影响， 目前还没有研究，主要是由于技术限制。我们之前进行了体内成像， 使用双光子显微镜，发现了小胶质细胞的动态性质，提供了第一个实时 展示其组织监视功能。我们还发现了它们以前未知的快速 应对微环境的变化。在系统性炎症挑战之后，小胶质细胞变成 激活，并增加它们与周围脑组织的相互作用。急性和慢性酒精暴露 全身性增加促炎细胞因子，这反过来又可以直接或间接影响血脑 屏障（BBB）的完整性，并促进不同脑区的神经炎症和神经毒性作用。我们 过量乙醇暴露模型的初步结果显示小胶质细胞活化，BBB破坏， 小鼠前额叶皮层（PFC）的神经元损失，这是一个与酒精诱导的损伤有关的大脑区域， 人类此外，单核细胞特异性缺失MyD 88，Toll样受体4下游的关键衔接蛋白， 消除乙醇滥用后的小胶质细胞活化、BBB损伤和神经元损失，并防止乙醇- 在小鼠中诱导损伤。基于这些发现，我们提出的研究将检验以下假设： 增加乙醇暴露导致局部BBB损伤和小胶质细胞活化，这是 神经网络的区域结构和功能破坏，以及酒精诱导的行为 损伤

ABSTRACT Exposure to alcohol during development or adulthood may result in damage to the brain. Binge alcohol consumption is a growing problem in the US, particularly among adolescents and young adults whose brains are continuing to develop and are thus more susceptible to the harmful effects of binge drinking on brain function. Both clinical and preclinical evidence suggest that microglia –the brain’s resident immune cells– play a key role in modulating alcohol-induced neurotoxicity. Indeed, brain inflammation following alcohol binge can impair brain development and function. In addition, activation of microglia promotes drinking preference in mouse models of chronic alcohol exposure. However, the cellular or molecular mechanisms through which microglia could mediate neuronal damage and alter animal behavior in response to alcohol in the adult or the adolescent brain have not been identified. Moreover, the effects of alcohol on microglia-neuronal interactions at the structural or functional level have not been studied, mostly due to technological limitations. We previously performed in vivo imaging using two-photon microscopy and discovered the dynamic nature of microglia, providing the first real-time demonstration of their tissue surveillance function. We also revealed their previously unknown ability to rapidly respond to changes in their microenvironment. Following systemic inflammatory challenges microglia become activated, and increase their interactions with the surrounding brain tissue. Acute and chronic alcohol exposure increases pro-inflammatory cytokines systemically, which can in turn directly or indirectly affect blood-brain barrier (BBB) integrity, and promote neuro-inflammatory and neurotoxic effects in different brain regions. Our preliminary results in models of excessive ethanol exposure show microglial activation, BBB disruption, and neuronal loss in the prefrontal cortex (PFC) of mice, a brain region implicated in alcohol-induced impairments in humans. Also, monocyte-specific deletion of MyD88, a key adaptor protein downstream of Toll-like receptor 4, abrogated microglial activation, BBB damage, and neuronal loss following ethanol abuse, and prevented ethanol- induced impairments in mice. Based on these findings, our proposed studies will test the hypotheses that increasing ethanol exposure causes localized BBB damage and microglial activation, which is required for regional structural and functional disruption of neuronal networks, and for alcohol-induced behavioral impairments.