Prenatal Alcohol and Adult Hippocampal Neurogenesis

描述（由申请人提供）：本提案的总体目标是阐明产前暴露于中等剂量的酒精导致浓缩介导的成年海马神经发生的长期损害的机制，并将这种缺陷与胎儿酒精谱系障碍（FASD）小鼠模型中海马依赖学习的损害联系起来。FASD小鼠在海马依赖性学习任务中表现出认知能力受损，并表现出抑郁障碍的迹象。FASD小鼠在成年海马神经发生方面也表现出持续的缺陷，这在小鼠暴露于富集环境时受到行为挑战时变得明显。在本研究中，实验旨在确定FASD表型背后的机制是否包括成体海马神经干细胞分化和成熟受损，以及成体生成的齿状颗粒细胞在空间记忆网络中的结合减少。为了验证这一点，我们将使用一种新的条件诱导性巢蛋白- CreERT2:YFP转基因小鼠，它可以对大量成体神经干细胞及其后代进行无创标记。FASD和Sacc（对照）小鼠将在巢蛋白- creert2:YFP菌株中产生，用于解决以下特定目的。目的1：确定产前乙醇暴露是否会损害成体海马神经干细胞的分化和成熟。巢蛋白- creert2:YFP菌株将用于FASD和Sacc（对照）小鼠体内（SA1.1）和体外分离成体NSCs （SA1.2）后成体海马神经干细胞的命运图谱和神经元分化特征。特异性目的2：确定产前暴露于酒精是否会损害成年出生的齿状颗粒细胞（DGCs）的突触成熟和可塑性。在FASD和Sacc巢巢- creert2:YFP小鼠的成年海马切片制备中，他莫昔芬将用于新生DGCs的出生和YFP标记，以进行电生理记录。使用这种方法，我们将测试产前酒精暴露破坏GABA和谷氨酸介导电流的成熟（SA2.1）和减弱成年出生的DGCs的LTP可塑性（SA2.2）的假设。特定目的3：确定产前乙醇暴露是否会损害新生成的DGCs优先融入空间记忆网络的能力。我们将通过巢蛋白- creert2:YFP小鼠的即时早期基因（c-fos）表达来确定FASD小鼠在回忆空间记忆任务时，成年海马新生神经元的优先激活是否减弱。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to elucidate the mechanisms by which prenatal exposure to moderate doses of alcohol results in long-lasting impairment of enrichment-mediated adult hippocampal neurogenesis, and to link this deficit with impairment of hippocampal-dependent learning in our mouse model of fetal alcohol spectrum disorder (FASD). FASD mice display impaired cognitive ability in hippocampal-dependent learning tasks and show signs of depressive disorder. FASD mice also display persistent deficits in adult hippocampal neurogenesis, which become apparent when the mice are behaviorally challenged by exposure to enriched environment. In this proposal, experiments are designed to determine whether the mechanisms underlying the FASD phenotype include impaired neuronal differentiation and maturation of neural stem cells in adult hippocampus, and diminished incorporation of adult-generated dentate granule cells into spatial memory networks. To test this, we will utilize a novel conditional and inducible nestin- CreERT2:YFP transgenic mouse which allows non-invasive labeling of large numbers of adult neural stem cells and their progeny. FASD and Sacc (control) mice will be generated in the nestin-CreERT2:YFP strain and utilized to address the following Specific Aims. Specific Aim 1 To determine whether prenatal ethanol exposure impairs neuronal differentiation and maturation of adult hippocampal neural stem cells. The nestin-CreERT2:YFP strain will be used to fate map and characterize neuronal differentiation of neural stem cells in adult hippocampus of FASD and Sacc (control) mice in vivo (SA1.1) and following isolation of adult NSCs in vitro (SA1.2). Specific Aim 2: To determine whether prenatal exposure to alcohol impairs synaptic maturation and plasticity of adult-born dentate granule cells (DGCs). Tamoxifen will be used to birthdate and YFP label newborn DGCs for electrophysiological recordings in adult hippocampal slice preparations from FASD and Sacc nestin-CreERT2:YFP mice. Using this approach, we will test the hypotheses that prenatal alcohol exposure disrupts the maturation of GABA- and glutamate-mediated currents (SA2.1) and attenuates LTP plasticity in adult born DGCs (SA2.2). Specific Aim 3: To determine whether prenatal ethanol exposure impairs the ability of newly- generated DGCs to preferentially incorporate into spatial memory networks. We will determine whether preferential activation of newborn neurons is attenuated in adult hippocampus of FASD mice during recall of a spatial memory task, as assessed by immediate early gene (c-fos) expression nestin-CreERT2:YFP mice. PUBLIC HEALTH RELEVANCE: This project will investigate how prenatal alcohol exposure acts to inhibit the production of new neurons within a region of the adult brain known as the hippocampus. The production of new neurons in this brain region is thought to be involved in the formation of certain types of memories. Understanding how prenatal alcohol exposure impacts the neurogenesis in the adult hippocampus may shed light on the mechanism underlying cognitive defects in Fetal Alcohol Spectrum Disorder, a prevalent condition that is observed in children whose mothers consumed moderate amounts of alcohol throughout pregnancy.