Network mechanisms of impaired adult hippocampal neurogenesis in a mouse model of prenatal alcohol exposure

项目总结/摘要 这项建议的总体目标是建立成人海马神经发生的相关性，作为一种潜在的 胎儿酒精谱系障碍（FASD）的治疗靶点，利用良好表征的小鼠模型， 产前酒精暴露（PAE）。成人海马神经发生作为一种潜在治疗手段的意义 胎儿酒精谱系障碍（FASD）靶点是基于临床前啮齿动物模型， 酒精暴露后神经发生的持续缺陷，神经发生的关键作用， 临床FASD中也会破坏许多依赖于大脑的行为，最近的证据表明， 神经发生在人的海马体中持续一生。使用自愿饮酒的范例来模拟 我们的实验室先前证明，在小鼠中， 环境（EE）与神经化学，形态学和电生理学的破坏有关 EE介导的网络活动指数。本提案中概述的实验旨在测试 假设EE介导的神经发生受损与行为和海马 网络机制，并可以使用遗传和/或药理学治疗恢复 接近。这一假设将通过解决以下具体目标进行检验。 具体目标1：确定EE介导的神经发生受损是否与以下因素直接相关： PAE小鼠的模式辨别学习受损。我们将利用两个复杂的神经发生依赖 在上下文和空间域中测试模式辨别/分离的认知任务。 行为表现将与PAE-EE小鼠中受损的神经发生相关，并且与PAE-EE小鼠中的立即早期神经发生相关。 基因表达作为网络激活的读数。 具体目的2：确定PAE小鼠中EE介导的神经发生受损是否导致 对aDGC的传入突触输入的补偿性重塑。我们将利用神经解剖学方法 包括基于狂犬病的逆行追踪，以确定树突的复杂性和/或 在PAE-EE小鼠中选择性地改变对aDGC的单突触传入输入。 具体目的3：确定PAE小鼠对EE介导的神经发生的敏感性是否恢复 通过遗传和/或药物干预。我们将利用基因功能获得的方法， 增加aDGC的存活，试图恢复PAE小鼠中EE介导的神经发生。另外我们 将测试神经源性抗抑郁药氟西汀（FLX）是否能恢复EE介导的神经发生， 在PAE中的行为如果是这样，神经发生和FLX介导的行为改善之间的因果关系 将通过aDGC的选择性遗传沉默进行测试。

PROJECT SUMMARY/ABSTRACT The overall goal of this proposal is to establish the relevance of adult hippocampal neurogenesis as a potential therapeutic target for fetal alcohol spectrum disorder (FASD), utilizing a well-characterized mouse model of prenatal alcohol exposure (PAE). The significance for adult hippocampal neurogenesis as a potential therapeutic target in fetal alcohol spectrum disorder (FASD) is based on preclinical rodent models that demonstrate long- lasting deficits in neurogenesis following developmental alcohol exposure, the critical role of neurogenesis in many hippocampal-dependent behaviors that are also disrupted in clinical FASD, and recent evidence that neurogenesis continues throughout life in the human hippocampus. Using voluntary drinking paradigms to model PAE in mice, our laboratory previously demonstrated marked impairment of the neurogenic response to enriched environment (EE) that is associated with disruption of neurochemical, morphological and electrophysiological indices of EE-mediated network activity. Experiments outlined in this proposal are designed to test the overall hypothesis that impaired EE-mediated neurogenesis is relevant for deficits in behavior and hippocampal network mechanisms in PAE, and can be restored using genetic and/or pharmacological therapeutic approaches. This hypothesis will be tested by addressing the following specific aims. Specific Aim 1: To determine whether impaired EE-mediated neurogenesis is directly correlated with impaired pattern discrimination learning in PAE mice. We will utilize two complex neurogenesis-dependent cognitive tasks in which pattern discrimination/separation is tested in both contextual and spatial domains. Behavioral performance will be correlated with impaired neurogenesis in PAE-EE mice, and with immediate early gene expression as a readout of network activation. Specific Aim 2: To determine whether impaired EE-mediated neurogenesis in PAE mice leads to compensatory remodeling of afferent synaptic input to aDGCs. We will utilize neuroanatomical approaches including rabies-based retrograde tracing to determine whether dendritic complexity and/or the distribution of monosynaptic afferent inputs to aDGCs are selectively altered in PAE-EE mice. Specific Aim 3: To determine whether sensitivity to EE-mediated neurogenesis in PAE mice is restored by genetic and/or pharmacological intervention. We will utilize a genetic gain-of-function approach to augment the survival of aDGCs in an attempt to restore EE-mediated neurogenesis in PAE mice. In addition, we will test whether the neurogenic antidepressant, fluoxetine (FLX), restores EE-mediated neurogenesis and behavior in PAE. If so, causal relationships between neurogenesis and FLX-mediated behavioral improvement will be tested by selective, genetic silencing of aDGCs.