Small G proteins and alcohol use disorder

摘要 这项建议旨在测试背侧纹状体中Rho GTP酶rac1和RhoB对 酒精使用障碍(AUD)的机制。Rac1和RhoB在细胞骨架中发挥重要作用 重排以及树突和棘突的重塑。我们最近发现，过度 酒精摄入和戒断激活小鼠背内侧纹状体(DMS)中的rac1和RhoB，以及 背外侧纹状体(DLS)。基于已公布的初步数据，我们将检验这一假设 酒精分别激活DMS和DLS神经元中的rac1和RhoB，导致细胞 适应，进而推动饮酒行为的发展和/或维持 包括目标导向和习惯性饮酒。 这一假说将通过以下目的来探讨。目标1将确定重物产生的机制 酒精使用激活了DMS和DLS中的rac1和RhoB。我们还将确定小G蛋白是否 在纹状体神经元的亚群中被激活。目标2将确定rac1和rac1的细胞后果 DMS和DLS中的RhoB分别被激活。具体地说，我将检验一种假设，即rac1的激活 DMS中的酒精促进了F-肌动蛋白的形成和树突的分枝，以及脊柱的成熟。我们 还将检验DLS中依赖酒精的RhoB激活会导致相反结果的假设，例如 树状突起萎缩，未成熟棘突数量增加。目标3将解决行为问题 RhoB和rac1激活在DMS和DLS中的作用，并决定小G蛋白是否 有助于养成和/或维持饮酒行为。最后，作为DMS和DLS 是不是电路中分别驱动目标导向和习惯性行为的中心区域，我们将确定 Rho1和RhoB是否驱使目标导向和习惯性饮酒。为了实现这些目标，我们计划 将最先进的分子/遗传工具与小鼠饮酒范例相结合。如果成功，数据 研究产生的结果将：a.阐明一组重要的信号分子的作用 将使我们能够深入了解酒精暴露是如何导致背部结构改变的 纹状体；C.将潜在地识别目标导向和/或习惯性酒精的分子机制 寻求；D.由于靶向Rho GTP酶的小分子正在开发用于其他适应症，该应用 有一个清晰的平移轨迹。

ABSTRACT This proposal is aimed at testing the contribution of the Rho GTPases Rac1 and RhoB in the dorsal striatum to the mechanisms underlying alcohol use disorder (AUD). Rac1 and RhoB play an important role in cytoskeleton rearrangement as well as in the remodeling of dendrites and spines. We recently discovered that excessive alcohol intake and withdrawal activate Rac1 and RhoB in the mouse dorsomedial striatum (DMS), and dorsolateral striatum (DLS), respectively. Based on published and preliminary data, we will test the hypothesis that alcohol activates Rac1 and RhoB, in DMS and DLS neurons, respectively, leading to cellular adaptations which in turn drive the development and/or maintenance of alcohol drinking behaviors including goal directed and habitual alcohol seeking. This hypothesis will be explored by the following aims. Aim 1 will determine the mechanism by which heavy alcohol use actives Rac1 and RhoB in the DMS and DLS. We will also determine whether the small G proteins are activated in subpopulation of striatal neurons. Aim 2 will determine the cellular consequences of Rac1 and RhoB activation in the DMS and DLS, respectively. Specifically, will examine the hypothesis that Rac1 activation by alcohol in the DMS promotes F-Actin formation and dendritic tree branching as well as spine maturation. We will also test the hypothesis that alcohol-dependent RhoB activation in the DLS leads to opposite outcomes e.g. dendritic tree shrinkage and increase in the number of immature spines. Aim 3 will address the behavioral consequences of Rac1 and RhoB activation in the DMS and DLS, and determine whether the small G proteins contribute to the development and/or maintenance of alcohol drinking behaviors. Finally, as the DMS and DLS are central regions in circuitries that drive goal directed and habitual behaviors, respectively, we will determine whether Rac1 and RhoB drive goal directed and habitual alcohol seeking. To achieve these goals, we plan to combine state of the art molecular/genetic tools with mouse alcohol drinking paradigms. If successful, data generated from the studies will: a. shed a light on the contribution of an important group of signaling molecules to AUD; b. will enable us to gain insights on how alcohol exposure produces structural modifications in the dorsal striatum; c. will potentially identify the molecular mechanisms underlying goal-directed and/or habitual alcohol seeking; d. as small molecules targeting Rho GTPases are being developed for other indications, the application has a clear translational trajectory.