Structural Analysis of Alcohol-dependent Activation of GIRKs

摘要 每年约有9万人死于酒精，酒精是第三大可预防的疾病 在美国的死因。酒精(乙醇)会使人上瘾，对身体产生复杂的影响， 主要是通过它在中枢神经系统内的相互作用。结构、细胞和电路 酒精对大脑产生影响并导致酒精使用障碍(AUD)的机制如下 人们对此知之甚少。大量研究表明，乙醇可以直接改变离子的功能。 通道，如G蛋白门控内向整流钾(GIRK)通道。GIRK通道的研究 基因敲除小鼠和人类GWA也涉及GIRK通道在介导乙醇的某些效应中的作用 大脑。然而，目前用于选择性调节GIRK通道的药理工具是有限的。这个 这项拨款的总体目标是阐明乙醇如何改变大脑功能，并确定新的配体 治疗澳元。在此之前，我们发现并鉴定了一种名为GiGA1的GIRK激活剂，它选择性地 激活GIRK1/GIRK2通道，不需要G蛋白，通过 激活内源性表达的GIRK通道，并表现出抗惊厥特性。GiGA1没有 然而，在澳元的背景下进行了彻底的测试。在这里，我们假设GiGA1的激活 GIRK1/2通道将缓解酒精对大脑奖赏回路的一些有害影响。具体来说， 我们将评估GiGA1对酒精调节行为(条件性位置偏爱，狂欢)的影响 饮酒和慢性间歇性酒精蒸气吸入引起的酒精摄入量增加)，确定 用体内纤维光度法检测GiGA1对NAC酒精调节环路的作用 释放神经递质，开发GIRK2选择性小分子调节剂。目前，有一个 FDA批准的治疗酒精中毒的药物数量有限，迫切需要新的治疗方法 治疗澳元。定义乙醇的物理口袋对于理解乙醇的结合如何 乙醇进入一条通道会导致通道活动的改变，影响大脑功能。现在，之前的桥接 乙醇如何通过酒精袋激活GIRK通道并延伸到创新的 用结构生物学指导筛选和选择新的治疗药物的方法，我们正在推进 直接激活GIRK通道亚型的化合物及其在小鼠糖尿病模型中的作用 AUDS。

Summary With approximately ninety thousand alcohol-related deaths per year, alcohol is the third leading preventable cause of death in the United States. Alcohol (ethanol) is addictive and produces complex effects on the body, primarily through its interactions within the central nervous system. The structural, cellular and circuit mechanisms by which ethanol imparts its effects on the brain and leads to alcohol use disorders (AUDs) are poorly understood. A large number of studies have demonstrated that ethanol directly alters the function of ion channels, such as the G protein-gated inwardly rectifying potassium (GIRK) channel. Studies of GIRK channel knockout mice and human GWAS also implicate GIRK channels in mediating some of the effects of ethanol in the brain. However, current pharmacological tools for selectively modulating GIRK channels are limited. The overall objectives of this grant are to elucidate how ethanol alters brain function and identify new ligands for treating AUD. Previously, we identified and characterized a GIRK activator, called GiGA1, which selectively activates GIRK1/GIRK2 channels, does not require G proteins, reduces the excitability of neurons via activation of endogenously expressed GIRK channels, and exhibits anti-convulsant properties. GiGA1 has not been thoroughly tested in the context of AUD, however. Here, we hypothesize that GiGA1 activation of GIRK1/2 channels will mitigate some of the deleterious effects of alcohol on brain reward circuits. Specifically, we will evaluate the effects of GiGA1 on alcohol-regulated behaviors (conditioned place preference, binge drinking, and ethanol intake escalation induced by chronic intermittent ethanol vapor inhalation), determine actions of GiGA1 on alcohol-regulated circuits in the NAc using in vivo fiber photometry to measure activity and release of neurotransmitters, and develop GIRK2-selective small molecule modulators. Currently, there is a limited number of FDA approved drugs for treating alcoholism and an urgent need for new approaches for treating AUD. Defining the physical pocket for ethanol has been critical for understanding how the binding of ethanol to a channel can lead to changes in channel activity and affect brain function. Now, bridging earlier studies on how ethanol activates GIRK channels via the alcohol pocket and extending to an innovative approach of using structural biology to guide screening and selection of novel therapeutics, we are advancing compounds that directly activate subtypes of GIRK channels and probing their efficacy in mouse models of AUDs.