Allosteric modulation of α1β3γ2 GABAA receptors by farnesol through the neurosteroid sites.
Allosteric modulation of α1β3γ2 GABAA receptors by farnesol through the neurosteroid sites.
复制标题
法呢醇通过神经类固醇位点对α1β3γ2 GABAA 受体进行变构调节。
DOI：
10.1016/j.bpj.2023.01.032
复制
发表时间：
2023
影响因子：
3.4
通讯作者：
Roullet,Jean-Baptiste
中科院分区：
文献类型：
--
作者：
Gc,JeevanB;Szlenk,ChristopherT;Diyaolu,Ayobami;Obi,Peter;Wei,Haiyang;Shi,Xutong;Gibson,KMichael;Natesan,Senthil;Roullet,Jean-Baptiste
在哺乳动物细胞中，全转阿尼醇是甲氧戊酸途径的产物，它是一种15碳的异丙肾上腺素。它是酒精脱氢酶的天然底物，也是与乙醇代谢有关的两种酶--CYP2E1的底物。研究表明，法尼醇存在于人脑中，其抑制电压门控钙通道的浓度比乙醇低得多。在这里，我们发现法尼醇调节γ-氨基丁酸A型受体(GABAARs)的活性，其中一些也介导乙醇的镇静活性。在表达人α-1-β-3-γ-2或α-6-β-3-γ-2受体的HEK细胞上进行的电生理实验表明，法尼醇通过对这些受体的正变构调节而增加氯电流，并显示其活性依赖于法尼醇的酒精官能团和烷基链的长度。在计算机研究中，采用长时间无偏全原子分子动力学(MD)对人α1β3γ2 GABA受体进行模拟，结果显示法尼醇通过直接与跨膜神经类固醇结合位点结合来调节通道，然后分配到周围膜并通过侧向扩散到达受体。法尼醇对通道的激活进一步表现为几个结构和动态变量，如受体胞外区的整体扭曲、跨膜M2螺旋的倾斜、半径、横截面积、水化状态和通道孔的静电势。我们的结果将法尼醇的药理活性扩展到另一类与神经传递有关的离子通道，从而为理解和治疗涉及GABA受体功能障碍的疾病提供了一条新的途径。
In mammalian cells,all-transfarnesol, a 15-carbon isoprenol, is a product of the mevalonate pathway. It is the natural substrate of alcohol dehydrogenase and a substrate for CYP2E1, two enzymes implicated in ethanol metabolism. Studies have shown that farnesol is present in the human brain and inhibits voltage-gated Ca2+channels at much lower concentrations than ethanol. Here we show that farnesol modulates the activity ofγ-aminobutyric acid type A receptors (GABAARs), some of which also mediate the sedative activity of ethanol. Electrophysiology experiments performed in HEK cells expressing humanα1β3γ2 orα6β3γ2 GABAARs revealed that farnesol increased chloride currents through positive allosteric modulation of these receptors and showed dependence on both the alcoholic functional group of farnesol and the length of the alkyl chain for activity. In silico studies using long-timescale unbiased all-atom molecular dynamics (MD) simulations of the humanα1β3γ2 GABAAreceptors revealed that farnesol modulates the channel by directly binding to the transmembrane neurosteroid-binding site, after partitioning into the surrounding membrane and reaching the receptor by lateral diffusion. Channel activation by farnesol was further characterized by several structural and dynamic variables, such as global twisting of the receptor's extracellular domain, tilting of the transmembrane M2 helices, radius, cross-sectional area, hydration status, and electrostatic potential of the channel pore. Our results expand the pharmacological activities of farnesol to yet another class of ion channels implicated in neurotransmission, thus providing a novel path for understanding and treatment of diseases involving GABAAreceptor dysfunction.