Alcohol Regulation of Synaptic and Extrasynaptic GluN2B-NMDA Receptors in BNST

描述(申请人提供)：酒精中毒是一种渐进性复吸障碍，尽管目前的治疗方法，复发率为50%-90%。开发新的治疗策略需要了解酒精中毒的神经生物学基础。复发的一个主要来源是与戒酒有关的负面影响(即焦虑和抑郁)。终纹的床核(BNST)是与酒精戒断相关的负面影响有关的大脑区域。BNST的长期适应是通过神经递质谷氨酸和NMDA受体(NMDAR)实现的。在BNST中，我最近的工作表明，酒精的急性和慢性行为是由特定的NMDAR亚单位(GluN2B)引起的。此外，长期饮酒会导致突触外位置通过这些GluN2B-NMDAR传递的增加。突触外GluN2B-NMDARs的信号传递与多种病理条件有关；然而，慢性酒精后GluN2B-NMDARs上调和重新定位的机制尚不清楚。在这项提案中，我将使用一种新的、高度特异的基于发现的蛋白质组学方法，结合电生理和生化技术来识别酒精诱导的突触和突触外位置GluN2B相互作用蛋白的变化。初步研究表明，慢性酒精可能会改变连接NMDAR和突触内信号伙伴的蛋白质(荷马蛋白、GKAPs、Shank、mGluR5和PSD蛋白)。我认为，慢性酒精使这些蛋白质不稳定，从而允许GluN2B-NMDARs的重新定位(目标1)。MGluR5是另一种谷氨酸受体，已被证明调节BNST的可塑性。这些受体也是已知的化塑性(NMDAR的可塑性)的媒介，在其他区域，发育亚单位从GluN2A转移到GluN2B。因此，mGluR5信号是慢性酒精后GluN2B-NMDARs增强的有力候选者(目标2)。虽然了解成年人的这些关键神经适应是关键，但临床数据表明，酒精依赖的最强预测因素是 青少年饮酒。基础研究发现，酒精在青少年和成年人之间有许多不同的影响；其中之一是在戒除慢性酒精期间的长期负面影响。大脑皮层和海马区(BNST输入)在青春期经历了NMDAR丰度的下降和NMDAR亚单位组成(GluN2B到2A)的转变。相比之下，BNST似乎在成年后仍保持高GluN2B水平。BNST内部这些不同发展轨迹的这种交集可能会导致独特的监管 在青春期的兴奋性传递和可塑性。因此，该提案的独立(R00)阶段将研究酒精驱动的NMDAR成分、定位和青春期信号的动态调节。

DESCRIPTION (provided by applicant): Alcoholism is a progressive relapsing disorder, with relapse rates from 50-90% in spite of current treatments. The development of new treatment strategies requires an understanding of the neurobiological underpinnings of alcoholism. A primary source of relapse is the negative affect (i.e. anxiety and depression) associated with alcohol withdrawal. The bed nucleus of the stria terminalis, BNST, is a brain region implicated in this negative affect associated with alcohol withdrawal. Long-term adaptations in the BNST occur through the neurotransmitter glutamate and the NMDA receptor (NMDAR). In the BNST, my recent work illustrates that the acute and chronic actions of alcohol are caused by a particular NMDAR subunit (GluN2B). Further, chronic alcohol leads to an increase in transmission through these GluN2B-NMDARs at extrasynaptic locations. Signaling through extrasynaptic GluN2B-NMDARs has been connected to a number of pathological conditions; however, the mechanisms underlying the upregulation and relocation of GluN2B-NMDARs after chronic alcohol are unknown. In this proposal, I will be using a novel, highly specific discovery-based proteomic approach in conjunction with electrophysiological and biochemical techniques to identify alcohol-induced changes in GluN2B interacting proteins in synaptic and extrasynaptic locations. Preliminary work suggests that chronic alcohol may alter proteins that link NMDARs and signaling partners within the synapse (Homer, GKAPs, Shank, mGlur5, and PSD proteins). I propose that destabilization of these proteins by chronic alcohol allows for the relocalization o GluN2B-NMDARs (Aim 1). mGluR5 is another glutamate receptor that has been shown to modulate plasticity in the BNST. These receptors are also known mediators of metaplasticity (plasticity of NMDARs) and the developmental subunit shifts from GluN2A to GluN2B in other regions. Therefore, mGluR5 signaling is a strong candidate for the enhancement of GluN2B-NMDARs following chronic alcohol (Aim 2). While understanding these critical neuroadaptations in adults is key, clinical data demonstrates that the strongest predictor for alcohol dependence is adolescent alcohol use. Basic research finds many differential effects of alcohol between adolescents and adults; one of these being prolonged negative affect during withdrawal from chronic alcohol. The cortex and hippocampus (BNST inputs) undergo declines in NMDAR abundance and shifts in NMDAR subunit composition (GluN2B to 2A) during adolescence. In contrast, the BNST seems to retain high GluN2B into adulthood. This intersection of these differential developmental trajectories within the BNST is likely to culminate in unique regulation of excitatory transmission and plasticity during adolescence. Therefore, the independent (R00) phase of this proposal will investigate alcohol-driven dynamic regulation of NMDAR composition, localization, and signaling during adolescence.