Design of Slack Channel Activators

Slack 通道激活器的设计

基本信息

批准号：
8241050
负责人：
LEONARD K KACZMAREK
金额：
$ 23.92万
依托单位：
YALE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-04-01 至 2013-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8241050
关键词：
Action Potentials Adverse effects Animals Anticonvulsants Area Ataxia Auditory Biological Assay Blood - brain barrier anatomy Brain Brain Stem Caenorhabditis elegans Calcium Calcium-Activated Potassium Channel Cell Nucleus Cell membrane Cells Cerebral Ischemia Cerebral Palsy Chemicals Cloning Collaborations Communities Drug Delivery Systems Drug Kinetics Drug or chemical Tissue Distribution Electrophysiology (science)Epilepsy Exhibits Family Genes Goals Grant Half-Life High Pressure Liquid Chromatography Hypoxia Injury Laboratories Libraries Measures Medial Membrane Potentials Molecular Mus Mutation Na(+)-K(+)-Exchanging ATPase Names Nematoda Nervous system structure Neuraxis Neurons Orthologous Gene Oxygen Participant Partition Coefficient Penetration Pharmaceutical Chemistry Plasma Proteins Play Potassium Potassium Channel Protein Binding Rattus Recombinants Role Screening procedure Series Sodium Specificity Stimulus Stroke Stroke prevention Surface System Test Result Testing Therapeutic Time United States National Institutes of Health abstracting base cell injury design high throughput screening hippocampal pyramidal neuron improved in vivo interest large-conductance calcium-activated potassium channels neocortical nervous system disorder neuronal excitability neurotoxicity novel olfactory bulb patch clamp pharmacophore prevent programs public health relevance research study small molecule tool trapezoid body

项目摘要

DESCRIPTION (provided by applicant): Sodium-activated potassium (KNa) channels are widely expressed throughout the central nervous system. Activation of these channels is known to protect cells from hypoxic injury. The molecular correlate of KNa currents, however, was unknown until the genes underlying this new family of K+ channels were cloned relatively recently. Slack (Sequence like a calcium-activated K channel) and Slick, which are also referred to as Slo2.2 (KCa4.1) and Slo2.1 (KCa4.2), currently have no pharmacological tools that allow for modulation of their function. With the help of this grant we are therefore proposing to design potent and brain-penetrant Slack channel activators that could be used to explore the therapeutic potential of these interesting channels. In normal neurons, KNa channels contribute to the slow afterhyperpolarizations that follows repetitive firing, regulate rates of bursting and enhance the accuracy with which action potentials lock to incoming stimuli. Evidence further indicates that KNa channels play a crucial role in protecting cells from injury under ischemic conditions, when inhibition of the plasma membrane Na+-K+-ATPase by the lack of oxygen leads to an increase in intracellular sodium levels. Activation of KNa channels under these circumstances is likely to prevent calcium entry by stabilizing the membrane potential and protecting neurons from overloading with calcium. In proof of this concept, mutation of the ortholog of Slack in the nematode C. elegans renders these animals hypersensitive to hypoxia indicating that KNa channels provide endogenous protection against hypoxia in this species. Compounds that increase the activity of KNa channel therefore should be therapeutically useful for the treatment of stroke and the prevention of the effects of global cerebral ischemia as occurs, for example, in cerebral palsy. By increasing the slow afterhyperpolarizations, KNa channel activators may also be useful for reducing neuronal excitability in epilepsy and ataxia. By screening various pharmacophores known to activate the related large-conductance Ca2+-activated K+ channel BK (Slo1, Maxi-K) it was recently discovered that biphenylthioles and 4-arylquinolinones activate Slack channels in the low micromolar range. Interestingly, two compounds in the 4-arylquinolone series were found to increase Slack activity without exerting effects on BK channels demonstrating that it is possible to separate the two activities. By combining i) classical medicinal chemistry, ii) a recently developed high- throughput assay measuring mass redistribution at the plasma membrane to determine Slack activation, iii) electrophysiology and iv) pharmacokinetic experiments in rats we here propose to improve the potency, selectivity and brain-penetration of our leads. Our overall goal is to provide the scientific community with a Slack channel activator that is suitable for in vivo use. PUBLIC HEALTH RELEVANCE: Based on their abundant expression in the brain sodium-activated potassium (KNa) channels potentially constitute novel drug targets for the treatment of stroke, cerebral palsy, epilepsy and ataxia. However, these important channels currently have no pharmacological modulators. With the help of this grant we will attempt to design small molecule KNa channel activators that could be used as scientific tool compounds to test whether KNa channels indeed constitute novel targets for neurological diseases.

描述（由申请人提供）：钠激活钾（KNa）通道在整个中枢神经系统中广泛表达。已知这些通道的激活可以保护细胞免受缺氧损伤。然而，直到最近克隆了这个新 K+ 通道家族的基因之前，KNa 电流的分子相关性还是未知的。 Slack（类似钙激活 K 通道的序列）和 Slick，也称为 Slo2.2 (KCa4.1) 和 Slo2.1 (KCa4.2)，目前没有可以调节其功能的药理学工具。因此，在这笔资助的帮助下，我们建议设计有效且具有大脑渗透性的 Slack 通道激活剂，可用于探索这些有趣通道的治疗潜力。在正常神经元中，KNa 通道有助于重复放电后的缓慢后超极化，调节爆发速率并提高动作电位锁定传入刺激的准确性。证据进一步表明，当缺氧抑制质膜 Na+-K+-ATP 酶导致细胞内钠水平增加时，KNa 通道在保护细胞免受缺血条件下损伤方面发挥着至关重要的作用。在这些情况下，KNa 通道的激活可能会通过稳定膜电位并保护神经元免于钙超载来阻止钙进入。为了证明这一概念，线虫中 Slack 的直系同源突变使这些动物对缺氧过敏，表明 KNa 通道为该物种提供了针对缺氧的内源性保护。因此，增加KNa通道活性的化合物应当在治疗上可用于治疗中风和预防例如在脑瘫中发生的全脑缺血的影响。通过增加缓慢的后超极化，KNa 通道激活剂也可能有助于降低癫痫和共济失调的神经元兴奋性。通过筛选已知可激活相关大电导 Ca2+ 激活的 K+ 通道 BK（Slo1、Maxi-K）的各种药效团，最近发现联苯硫醇和 4-芳基喹啉酮可在低微摩尔范围内激活 Slack 通道。有趣的是，我们发现 4-芳基喹诺酮系列中的两种化合物可以增加 Slack 活性，而不会对 BK 通道产生影响，这表明可以将这两种活性分开。通过结合 i) 经典药物化学，ii) 最近开发的高通量测定法，测量质膜上的质量重新分布以确定 Slack 激活，iii) 电生理学和 iv) 大鼠药代动力学实验，我们在此建议提高效力、选择性和大脑-我们的线索的渗透。我们的总体目标是为科学界提供适合体内使用的 Slack 通道激活剂。公共健康相关性：基于其在大脑钠激活钾 (KNa) 通道中的丰富表达，可能构成治疗中风、脑瘫、癫痫和共济失调的新药物靶点。然而，这些重要通道目前还没有药理调节剂。借助这笔资金，我们将尝试设计小分子 KNa 通道激活剂，将其用作科学工具化合物，以测试 KNa 通道是否确实构成神经系统疾病的新靶点。