Endocannabinoid Signaling in Postnatal Ethanol Effects

描述(由申请人提供)：已知酒精暴露对发育中的胎儿有不利影响。在人类怀孕的第三个月(啮齿动物出生后1-14天)，在突触发生期间使用乙醇会触发细胞凋亡。乙醇的使用影响了海马区的功能，损害了突触的可塑性、学习和记忆。我们在KO1获奖期间的工作导致了这样的假设，即乙醇通过增加海马神经元内源性大麻素[ECs；ANANDIAME(AEA)和2-花生四烯基甘油(2-AG)]的产生而对突触可塑性产生影响。与乙醇一样，大麻素(CB)本身也抑制突触的可塑性，并显著加剧乙醇对发育中大脑的凋亡效应。CB介导的突触活动在大脑发育早期似乎会影响大脑成熟途径，从而影响认知缺陷。然而，乙醇影响EC偶联通路的细胞机制(S)在很大程度上仍不清楚。我们的初步数据表明，在突触发生期间给予乙醇可以激活大麻素1型(CB1R)受体，诱导神经变性。此外，CB1R活性的增强会导致成年动物pCREB水平和突触可塑性的缺陷。CB1R阻滞剂挽救了新生小鼠的神经退化。它还挽救了在成年动物身上观察到的突触功能障碍。我们有希望的初步数据，涉及内皮细胞和CB1R介导的机制，强调了这一研究方向的重要性。我们的中心假设是，在突触发生过程中，乙醇介导的海马区CB1R通路的激活导致突触可塑性的长期缺陷。我们提出了三个具体目标来解决这一假设。该方法结合了CB1R基因缺失小鼠的使用以及已建立的免疫学、生化方法和电生理学技术。在特定的目标1中，我们将研究在突触发生期间出生后给予乙醇对AEA和2-AG代谢去向以及CB1Rs表达和功能的影响。在具体目标2中，我们将研究出生后乙醇效应是如何耦合到CB1R依赖的信号通路的。在具体目标3中，我们将测试出生后早期酒精暴露是否会导致成年动物海马区突触可塑性的长期抑制。了解海马区EC通路(S)的分子基础将有助于开发潜在的CB1R靶向策略，用于治疗海马区异常以及通常因怀孕期间酗酒而导致的记忆和学习障碍。 与公共卫生相关：希望更好地了解中枢神经系统发育过程中乙醇暴露如何改变海马体中的内源性大麻素途径，将导致更有效的策略来治疗因怀孕期间酗酒而导致的儿童海马区异常和相关记忆和学习障碍，这是西方世界最常见的发育障碍。此外，建议的研究结果可能被卫生保健专业人员用来就饮酒的潜在影响向孕妇提供咨询。

DESCRIPTION (provided by applicant): Ethanol exposure is known to have adverse effects on the developing fetus. Ethanol use during the synaptogenesis period, which occurs over the third trimester of pregnancy in humans (1-14 days after birth in rodents), triggers apoptotic cell death. The use of ethanol affects hippocampal functions impairing synaptic plasticity, learning and memory. Our work during the KO1 award period has led to the hypothesis that ethanol exerts its effects on synaptic plasticity via increased production of endogenous cannabinoids [ECs; anandamide (AEA) and 2-arachidonylglycerol (2-AG)] in hippocampal neurons. Cannabinoids (CB) themselves, like ethanol inhibit synaptic plasticity and markedly exacerbate the apoptotic effects of ethanol in the developing brain. The CB-mediated synaptic activity during early brain development seems to affect brain maturation pathways that influence cognitive deficits. However, the cellular mechanism(s) by which ethanol affects EC-coupled pathways remains largely unknown. Our preliminary data suggest that ethanol administration during the synaptogenic period activates the cannabinoid type 1 (CB1R) receptor inducing neurodegeneration. In addition, the enhanced CB1R activity causes deficits in pCREB levels and synaptic plasticity in adult animals. The CB1R blockade rescues neurodegeneration in neonatal mice. It also rescues the synaptic dysfunction observed in adult animals. Our promising preliminary data, implicating ECs and CB1R-mediated mechanisms, underscores the importance of this research direction. Our central hypothesis is that ethanol-mediated activation of hippocampal CB1R pathways during synaptogenesis results in long-lasting deficits in synaptic plasticity. We propose three Specific Aims to address this hypothesis. The approach combines the use of CB1R null mice and the established immunological, biochemical methods and electrophysiology techniques. In Specific Aim 1, we will investigate the effects of postnatal ethanol administration during the synaptogenesis period on the metabolic fate of AEA and 2-AG, and CB1Rs expression and function. In Specific Aim 2, we will investigate as to how postnatal ethanol effects are coupled to the CB1R-dependent signaling pathways. In Specific Aim 3, we will test whether the early postnatal ethanol exposure causes long lasting depression of hippocampal synaptic plasticity in adult animals. Understanding the molecular underpinnings of the EC pathway (s) in the hippocampus will help to develop potential CB1R targeted strategies for treating hippocampal abnormalities and memory and learning deficits that often result from alcohol abuse during pregnancy. PUBLIC HEALTH RELEVANCE: It is hoped that better understanding of how ethanol exposure during CNS development alters endocannabinoid pathways in the hippocampus will lead to more effective strategies for the treatment of hippocampal abnormalities and related memory and learning deficits in children due to alcohol abuse during pregnancy, representing the most common developmental disability in the Western world. Additionally, the results of the proposed studies may be used by health care professionals in counseling pregnant women on the potential effects of alcohol consumption.