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。在可兴奋的细胞中，钾通道参与了膜的设置 动作电位和动作电位的调制。由KCNT1编码的空闲信道是SLO家族的成员 钾通道包括slo1(Maxi-K)、slo2.1(Slick)、slo2.2(Slack)和精子特异性的slo3 频道。最近，多项研究已经确定了Slack通道中的大约30个突变与 各种癫痫，最常见的是婴儿期恶性迁移性部分发作(MMPSI)。MMPSI是 极其严重，耐药，通常在生命的第一年死亡。关联的Slak变体 与这些癫痫发现在三个集群：毛孔的经络，并在两个独立的羧基末端 调节区，K+(RCK)和NAD+结合域的电导调节器。有趣的是，这些 突变是显性的、功能获得突变，导致更高程度的Slack通道活动。 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 尚不清楚，我们假设Slack通道的特定抑制剂可能提供一种有效的抗癫痫药物 策略。因此，该提案的目标是构建一个以命中发现和表征为重点的基础设施 关于提供对野生型Slack和3 MMPSI相关的110,000个复合筛查的能力 突变体，来自三个簇中的每一个(R21期)。我们将利用这一基础设施和集中的打击- 领导药物化学工作，包括旨在提高药物相似性的分析和策略，以 支持发现和表征松弛特异性抑制物(R33阶段)。建议的目标是 研究是发现和验证至少两种小分子支架，为开发提供平台 这是体内活性松弛抑制剂的一部分，并为注重治疗的铅优化工作奠定了基础。

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.