Design of Slack Channel Activators

Slack 通道激活器的设计

基本信息

批准号：
8092226
负责人：
LEONARD K KACZMAREK
金额：
$ 25.51万
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/8092226
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 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）：钠激活的钾（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保护细胞免受低氧损伤。但是，直到该新的K+通道家族的基因被相对克隆，KNA电流的分子相关性是未知的。 Slack（像钙激活的K通道一样序列）和Slick，也称为Slo2.2（KCA4.1）和Slo2.1（KCA4.2），目前没有允许调节其功能的药理工具。因此，在这笔赠款的帮助下，我们建议设计有效和脑部的松弛通道激活因子，这些渠道可用于探索这些有趣的通道的治疗潜力。在正常的神经元中，KNA通道有助于重复发射后缓慢的输卵管过滤，调节爆发速率并提高动作电位锁定到传入刺激的准确性。证据进一步表明，当抑制缺乏氧气的质膜Na+-k+-ATPase时，KNA通道在保护细胞免受缺血状况下的损伤中起着至关重要的作用，导致细胞内钠水平的增加。在这种情况下，KNA通道的激活很可能通过稳定膜电位并保护神经元免受钙的过载来防止钙进入。为了证明这一概念，线虫秀丽隐杆线虫中松弛的直系同源物的突变使这些动物对缺氧性低敏，这表明KNA通道可为该物种中的缺氧提供内源性保护。因此，增加KNA通道活性的化合物应在治疗上可用于治疗中风和预防全球脑缺血的作用，例如，例如在脑瘫中。通过增加缓慢的毕竟过滤，KNA通道激活剂也可能有助于降低癫痫和共济失调中的神经元兴奋性。通过筛选已知可以激活相关大型CA2+激活的K+通道BK（SLO1，Maxi-K）的各种药物团，最近发现双苯基硫醇和4-芳基素烯酮激活了低微压范围内的松弛通道。有趣的是，发现4-芳基酮系列中的两种化合物可以增加松弛活动，而不会对BK通道发挥作用，表明可以将两种活动分开。通过结合i）经典药物化学，ii）最近开发的高吞吐量测定，测量质膜处的质量重新分布以确定松弛激活，iii）电生理学和iv）大鼠的药代动力学实验，我们在这里建议提高我们的潜在的效力，选择性，选择性和脑脑。我们的总体目标是为科学界提供适合体内使用的松弛频道激活器。公共卫生相关性：基于它们在脑钠激活钾（KNA）中的丰富表达，潜在地构成了中风，脑瘫，癫痫和共济失调的新型药物靶标。但是，这些重要的渠道目前没有药理调节剂。在这笔赠款的帮助下，我们将尝试设计小分子KNA通道激活剂，该激活剂可以用作科学工具化合物，以测试KNA通道是否确实构成了神经疾病的新靶标。