Ethanol Alteration of the Neurogenic Niche

抽象的。 酒精使用障碍(AUD)仍然是美国的主要公共卫生问题之一，近14%的人 符合诊断标准的美国人口。酗酒者表现出与酒精相关的认知障碍 大脑质量丧失或海马区等区域的神经变性，这种影响可能会随着 禁欲。这种恢复的机制尚不清楚，但我们实验室的最新发现表明 酒精诱导的海马神经干细胞的调节和成人神经发生的变化与 酒精中毒(减少/缺失)与戒酒(增加/恢复)时的脑质量和认知。 在过去的资助期间，我们的实验室已经表明，既往的酒精依赖会导致 禁欲中的成人神经发生，一种由于神经干细胞和祖细胞重新激活而产生的影响 驱动这种反应性神经再生反应的自行车运动。尽管该响应最初看起来是修复性的， 基于酒精大鼠在海马区依赖的学习任务中表现出的行为恢复，干细胞 激活会产生长期后果。具体地说，通过神经干细胞激活的反应性神经发生可以 耗尽或耗尽神经干细胞库，最终导致神经发生和损伤减少 长期观察海马区的结构和功能。此外，神经干细胞激活的机制 AUDS模型的作用尚不清楚，但来自干细胞激活和酒精神经可塑性的证据汇聚在一起 文献结合我们的初步数据支持哺乳动物雷帕霉素靶标(MTOR)信号转导的作用。 因此，我们的首要假设是反应性神经发生最初是有益的，这是由于 通过诱导mTOR信号从酒精依赖中招募神经干细胞走出静止状态， 但神经干细胞的激活可能会以神经干细胞枯竭为代价，并最终造成有害的 对海马区结构和功能的影响。利用跨学科的组织学、生物化学、 电生理和行为方法，我们建议检查的作用，后果，和 AUD四天狂欢模型中反应性神经发生的机制：1) 确定反应性神经发生在酒精戒断后的结构、功能和恢复中的作用 依赖，2)检验酒精依赖后反应性神经发生激活神经干细胞的假设 处于静止状态的细胞最终耗尽/耗尽神经干细胞库，以及3)确定mTOR的作用 酒精依赖后神经干细胞激活和反应性神经发生的信号转导。我们的终极目标 目的是阐明成人神经发生在促进戒断SO的结构和功能恢复中的作用 未来的研究可以在药理学或行为学上将这一途径作为一种新的治疗策略 酒精性脑损伤的治疗。

Abstract. Alcohol use disorders (AUDs) remain one of the nation's major public health problems with nearly 14% of U.S. population meeting diagnostic criteria. Alcoholics demonstrate cognitive impairments that are related to a loss of brain mass or neurodegeneration in regions such as the hippocampus, an effect that may recover with abstinence. The mechanism of this recovery is not clear, however recent discoveries from our laboratory show that alcohol-induced regulation of hippocampal neural stem cells and adult neurogenesis parallel the changes in brain mass and cognition during alcohol intoxication (decrease/deficit) versus abstinence (increase/recovery). Across the last funding period, our lab has shown that prior alcohol dependence results in a striking increase in adult neurogenesis in abstinence, an effect due to the recruitment of neural stem and progenitor cells into active cycling that drives this reactive neurogenesis response. Although this response appears reparative initially, based on ethanol rats showing behavioral recovery on a hippocampal-dependent learning task, stem cell activation has long term consequences. Specifically, reactive neurogenesis via neural stem cell activation can deplete or exhaust the neural stem cell pool, ultimately resulting in decreased neurogenesis and impairments in hippocampal structure and function in the long-term. Furthermore, the mechanism of neural stem cell activation in models of AUDs is not known, but converging evidence from stem cell activation and alcohol neuroplasticity literatures coupled with our preliminary data support a role for mammalian target of rapamycin (mTOR) signaling. Thus, our overarching hypothesis is that reactive neurogenesis is initially beneficial, resulting from the recruitment of neural stem cells out of quiescence via an induction of mTOR signaling from alcohol dependence, but neural stem cell activation may come at the expense of neural stem cell depletion and an eventual detrimental impact on hippocampal structure and function. Using an interdisciplinary array of histological, biochemical, electrophysiological and behavioral approaches, we propose to examine the role of, consequences of, and mechanisms of reactive neurogenesis in a four-day binge model of an AUD through three specific aims: 1) Determine the role of reactive neurogenesis in structure, function, and recovery in abstinence after alcohol dependence, 2) Test the hypothesis that reactive neurogenesis after alcohol dependence activates neural stem cells out of quiescence to ultimately deplete / exhaust the neural stem cell pool, and 3) Define the role of mTOR signaling in neural stem cell activation and reactive neurogenesis after alcohol dependence. Our ultimate goal is to elucidate the role of adult neurogenesis in promoting structural and functional recovery in abstinence so that future studies can target this pathway pharmacologically or behaviorally as a novel therapeutic strategy in the treatment of alcoholic brain damage.