PDF(Pubmed)
Abstract：
Genetic abnormalities have been associated with primary aldosteronism, a major cause of secondary hypertension. This includes mutations in the KCNJ5 gene, which encodes G protein-gated inwardly rectifying K+ channel 4 (GIRK4). For example, the substitution of glycine with glutamic acid gives rise to the pathogenic GIRK4G151E mutation, which alters channel selectivity, making it more permeable to Na+ and Ca2+. While tertiapin and tertiapin-Q are well-known peptide inhibitors of the GIRK4WT channel, clinically, there is a need for the development of selective modulators of mutated channels, including GIRK4G151E. Using in silico methods, including homology modeling, protein-peptide docking, ligand-binding site prediction, and molecular docking, we aimed to explore potential modulators of GIRK4WT and GIRK4G151E. Firstly, protein-peptide docking was performed to characterize the binding site of tertiapin and its derivative to the GIRK4 channels. In accordance with previous studies, the peptide inhibitors preferentially bind to the GIRK4WT channel selectivity filter compared to GIRK4G151E. A ligand-binding site analysis was subsequently performed, resulting in the identification of two potential regions of interest: the central cavity and G-loop gate. Utilizing curated chemical libraries, we screened over 700 small molecules against the central cavity of the GIRK4 channels. Flavonoids, including luteolin-7-O-rutinoside and rutin, and the macrolides rapamycin and troleandomycin bound strongly to the GIRK4 channels. Similarly, xanthophylls, particularly luteoxanthin, bound to the central cavity with a strong preference towards the mutated GIRK4G151E channel compared to GIRK4WT. Overall, our findings suggest potential lead compounds for further investigation, particularly luteoxanthin, that may selectively modulate GIRK4 channels.
摘要：
遗传异常与原发性醛固酮增多症有关，继发性高血压的主要原因。这包括KCNJ5基因的突变,它编码G蛋白门控向内整流K通道4（GIRK4）。例如,甘氨酸与谷氨酸的取代引起致病性GIRK4G151E突变，这改变了信道选择性，使其对Na+和Ca2+更具渗透性。虽然tertiapin和tertiapin-Q是众所周知的GIRK4WT通道的肽抑制剂，临床上,需要开发突变通道的选择性调节剂，包括GIRK4G151E.使用计算机模拟方法，包括同源性建模，蛋白质-肽对接，配体结合位点预测，和分子对接，我们旨在探索GIRK4WT和GIRK4G151E的潜在调节剂。首先,进行蛋白质-肽对接以表征tertiapin及其衍生物与GIRK4通道的结合位点。根据以前的研究，与GIRK4G151E相比,肽抑制剂优先结合GIRK4WT通道选择性过滤器。随后进行配体结合位点分析，从而识别出两个潜在的感兴趣区域：中心腔和G环门。利用精选的化学图书馆，我们针对GIRK4通道的中央腔筛选了700多个小分子。黄酮类化合物,包括木犀草素-7-O-rutinoside和芦丁，大环内酯类雷帕霉素和曲洛多姆霉素与GIRK4通道强烈结合。同样，叶黄素，尤其是叶黄素,与GIRK4WT相比，与中央腔结合，对突变的GIRK4G151E通道具有强烈的偏好。总的来说,我们的研究结果表明潜在的先导化合物需要进一步研究，尤其是叶黄素,可以选择性地调节GIRK4通道。
