Slack Potassium Channel Inhibitors for the Treatment of Childhood Epilepsies

摘要 钾通道对生命至关重要，发挥着多种生理作用，包括控制溶质平衡， 细胞体积和细胞兴奋性。在可兴奋细胞中，钾通道参与膜的形成 电位和动作电位的调节。由KCNT 1编码的Slack通道是Slo家族的成员 钾通道，包括Slo 1（Maxi-K），Slo2.1（Slick），Slo2.2（Slack）和Slo 3，精子特异性 频道最近，多项研究已经在Slack通道中发现了约30种突变，这些突变与以下疾病相关： 各种癫痫，最常见的是婴儿恶性游走性部分性癫痫发作（MMPSI）。MMPSI是 非常严重，耐药性，通常在生命的第一年内致命。相关的松弛变体 与这些癫痫被发现在三个集群：孔的通道，并在两个单独的羧基末端 调节区域，K+电导调节器（RCK）和NAD+结合结构域。有趣的是，这些 突变是显性的，功能获得性突变导致更高程度的Slack通道活性。 尽管Slack过度活动导致MMPSI和其他不太严重的癫痫的确切机制 我们假设Slack通道的特异性抑制剂可能提供一种可行的抗癫痫药物， 战略因此，本提案的目的是建立一个命中发现和表征基础设施， 提供对野生型Slack和3种MMPSI相关的化合物进行110，000种化合物筛选的能力 突变体，来自三个簇（R21相）中的每一个。我们将利用这一基础设施和集中打击- 领导药物化学工作，包括旨在增强药物相似性的测定和策略， 支持Slack特异性抑制剂（R33阶段）的发现和表征。建议的目标 研究是发现和验证至少两个小分子支架，为开发提供平台 体内活性的Slack抑制剂和治疗重点的铅优化工作的基础。

ABSTRACT Potassium channels are critical for life, playing a variety of physiological roles including control of solute balance, cell volume, and cellular excitability. In excitable cells potassium channels are involved in setting membrane potential and modulation of action potentials. Slack channels, encoded by KCNT1, are members of the Slo family of potassium channels, comprised of Slo1 (Maxi-K), Slo2.1 (Slick), Slo2.2 (Slack) and Slo3, a sperm-specific channel. Recently, multiple studies have identified ~30 mutations in Slack channels that are associated with a variety of epilepsies, most frequently Malignant Migrating Partial Seizures of Infancy (MMPSI). MMPSI are extremely severe, pharmacoresistant, and typically fatal during the first year of life. Slack variants associated with these epilepsies are found in three clusters: the pore of the channel, and in two separate carboxy-terminal regulatory regions, Regulator of Conductance of K+ (RCK) and NAD+ binding domains. Interestingly, these mutations are dominant, gain-of-function mutations resulting in a higher degree of Slack channel activity. Although the exact mechanism by which over-activity of Slack leads to MMPSI and other, less severe epilepsies is not understood, we hypothesize that specific inhibitors of Slack channels may provide a viable anti-epileptic strategy. Thus, the aims of this proposal are to build a hit-discovery and characterization infrastructure focused on providing an ability to conduct an 110,000 compound screen on wild-type Slack and 3 MMPSI-associated mutants, one from each of the three clusters (R21 Phase). We will utilize this infrastructure and a focused hit-to- leads medicinal-chemistry effort, including assays and strategies geared toward enhancing drug-likeness, to support the discovery and characterization of Slack-specific inhibitors (R33 Phase). The goal of the proposed research is to discover and validate at least two small molecule scaffolds, providing a platform for development of in vivo-active Slack inhibitors and a foundation for a therapeutically focused lead optimization effort.