Structure-based identification and characterisation of novel inhibitors of K Na 1.1 potassium channels, a stratified target for KCNT1 -related epilepsy
Structure-based identification and characterisation of novel inhibitors of K Na 1.1 potassium channels, a stratified target for KCNT1 -related epilepsy
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基于结构的 K Na 1.1 钾通道抑制剂（KCNT1 相关癫痫的分层靶标）的鉴定和表征
DOI：
10.1101/779975
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Cole B
中科院分区：
文献类型：
--
作者：
Cole B
几种类型的婴儿期耐药性癫痫性脑病与 KCNT1 基因的突变有关，该基因编码钠激活钾通道亚基 KNa1.1。这些突变通常是功能获得性的，增加通道活性，因此药物抑制被提议作为治疗疾病的分层方法。迄今为止，奎尼丁疗法已在几位患者身上进行了试验，但大多数结果都不成功，这与其效力低且缺乏特异性有关。在这里，我们描述了使用冷冻电子显微镜衍生的 KNa1.1 结构和突变分析来识别奎尼丁结合位点，并使用计算方法识别出针对该位点的新型抑制剂。我们描述了六种以低微摩尔和亚微摩尔效力抑制 KNa1.1 通道的化合物，可能是通过与细胞内孔前庭结合而实现的。在初步的 hERG 抑制和细胞毒性测定中，两种化合物几乎没有显示出效果。这些化合物可能为开发 KNa1.1 抑制的新型药效团提供起点，以治疗 KCNT1 相关的癫痫，并且其效力高于奎尼丁，可能成为进一步研究该通道的关键工具化合物。此外，这项研究说明了利用冷冻电子显微镜在离子通道药物发现中的潜力。
Several types of drug-resistant epileptic encephalopathies of infancy have been associated with mutations in theKCNT1gene, which encodes the sodium-activated potassium channel subunit KNa1.1. These mutations are commonly gain-of-function, increasing channel activity, therefore inhibition by drugs is proposed as a stratified approach to treat disorders. To date, quinidine therapy has been trialled with several patients, but mostly with unsuccessful outcomes, which has been linked to its low potency and lack of specificity. Here we describe the use of a cryo-electron microscopy-derived KNa1.1 structure and mutational analysis to identify the quinidine biding site and identified novel inhibitors that target this site using computational methods. We describe six compounds that inhibit KNa1.1 channels with low- and sub-micromolar potencies, likely through binding in the intracellular pore vestibule. In preliminary hERG inhibition and cytotoxicity assays, two compounds showed little effect. These compounds may provide starting points for the development of novel pharmacophores for KNa1.1 inhibition, with the view to treatingKCNT1-associated epilepsy and, with their potencies higher than quinidine, could become key tool compounds to further study this channel. Furthermore, this study illustrates the potential for utilising cryo-electron microscopy in ion channel drug discovery.