Development of an In Vivo, Brain-penetrant GIRK1/2 Potassium Channel Activator

体内脑渗透性 GIRK1/2 钾通道激活剂的开发

• 批准号: 8941166
• 负责人: Corey R. Hopkins
• 金额: $ 58.33万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-15 至 2018-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8941166
• 关键词: Ablation; Address; Anti-Anxiety Agents; Anxiety; Behavior; Biological; Biological Assay; Biology; Brain; Cardiac; Cell Line; Cells; Complex; Development; Disease; Drug Kinetics; Elements; Epilepsy; Evaluation; Exhibits; Face; Family; GIRK1 subunit, G protein-coupled inwardly-rectifying potassium channel; GIRK2 subunit, G protein-coupled inwardly-rectifying potassium channel; GTP-Binding Proteins; Genes; Genetic; Goals; Half-Life; Heart; Heart Atrium; Heart Rate; Hippocampus (Brain); Homo; In Vitro; Incidence; Induced Hyperthermia; Intervention; Investigation; Ion Channel; Libraries; Mediator of activation protein; Mental disorders; Mission; Modeling; Motor Activity; Mus; National Institute of Mental Health; Neurons; Nodal; Organ; Pain; Penetration; Perception; Pharmaceutical Chemistry; Pharmacodynamics; Physiological; Physiology; Plasma; Potassium; Potassium Channel; Process; Property; Rattus; Regulation; Relative (related person); Research; Research Personnel; Research Project Grants; Role; Seizures; Severities; Solubility; Stress; Testing; Thallium; Therapeutic; Validation; Work; anxiety-related behavior; anxiety-related disorders; aqueous; behavior test; disease mechanisms study; high throughput screening; improved; in vivo; interest; inward rectifier potassium channel; meetings; novel; prevent; public health relevance; scaffold; small molecule; tool

 DESCRIPTION (provided by applicant): G protein-gated Inwardly-Rectifying K+ (GIRK) channels are critical mediators of cell excitability in the brain and heart. GIRK channels are homo- and heterotetrameric complexes formed by four subunits (GIRK1-4). While evidence from gene ablation studies in mice suggests that specific GIRK channel subtypes make discrete contributions to organ physiology and behavior, the lack of subtype-selective GIRK channel probes has prevented rigorous evaluation of the consequences, and therapeutic potential, associated with GIRK channel activation. Recently, we identified a promising GIRK channel activator scaffold using a high-throughput screening approach. This scaffold was used to develop ML297, the first subtype-selective, small-molecule GIRK channel activator. ML297 is potent and strongly-selective for GIRK1-containing relative to GIRK1-lacking channels. ML297 reduces anxiety-related behavior in a GIRK1-dependent manner in mice, and suppresses seizures in rat epilepsy models. However, ML297 suffers from poor aqueous solubility, as well as low brain penetration and rapid clearance following systemic administration. Moreover, ML297 exhibits only modest selectivity for the predominant neuronal GIRK channel (GIRK1/2) relative to other GIRK1-containing subtypes, including the cardiac GIRK channel (GIRK1/4). These features of ML297 limit its utility as an in vivo probe for elucidating the relevance and therapeutic potential associated with GIRK1/2 channel activation. Accordingly, the goal of this project is to use the ML297 scaffold to develop new GIRK1/2 activators with an improved channel subtype selectivity profile and pharmacokinetic properties required of a brain-penetrant, in vivo probe. The project combines state-of-the-art approaches in medicinal chemistry and compound characterization, and will be conducted by an investigative team with complementary expertise in GIRK channel biology and in vivo probe development. The work is framed around three Specific AIMs: 1) To develop potent and selective GIRK1/2 channel activators, 2) To develop GIRK1/2 channel activators with optimized pharmacokinetic properties, and 3) To characterize the pharmacodynamics properties of GIRK1/2 channel activators in vivo. Work in AIMs 1 and 2 will involve an iterative parallel medicinal chemistry synthesis and testing strategy, and will yield GIRK1/2 activators with pharmacodynamic and pharmacokinetic properties superior to those of ML297. In AIM 3, these compounds will be characterized for in vivo efficacy, selectivity, and potency in the stress-induced hyperthermia (SIH) test, a paradigm with strong face validity for anxiolytic compounds. A small set of optimized probes exhibiting GIRK1/2-dependent efficacy in this test will undergo further evaluation in another anxiety model, and tests that explore the effects of the GIRK1/2 probes on motor activity and coordination. Completion of this research project will yield selective and effective in vivo probes for GIRK1/2 channels. These probes will facilitate future research into the relevance and therapeutic potential of GIRK1/2 channels, including more rigorous evaluation of their utility for treatment of anxiety-related disorders.

 描述（由适用提供）：G蛋白门控的内部矫正K+（Girk）通道是大脑和心脏中细胞兴奋性的关键介体。 Girk通道是由四个亚基形成的同型和异光复合物（GIRK1-4）。虽然小鼠基因消融研究的证据表明，特定的GIRK通道亚型对器官生理和行为做出了离散的贡献，但缺乏亚型选择性的girk通道问题，已经阻止了对后果的严格评估，并且与GIRK通道激活相关的治疗潜力。最近，我们使用高通量筛选方法确定了一个承诺的Girk通道激活器支架。该脚手架用于开发ML297，这是第一个亚型选择性的小分子Girk通道激活剂。 ML297对于相对于GIRK1占用的通道具有潜力且强烈选择性。 ML297在小鼠中以GIRK1依赖性方式降低了与焦虑相关的行为，并抑制了大鼠癫痫模型中的癫痫发作。然而，ML297的水溶液不良，全身给药后的脑穿透性低和快速清除率。此外，相对于其他含GIRK1的亚型（包括心脏GIRK1/4），ML297仅表现出主要的神经元GIRK通道（GIRK1/2）的适度选择性。 ML297的这些特征限制了其作为体内探针的实用性，以阐明与GIRK1/2通道激活相关的相关性和治疗潜力。根据该项目的目标是使用ML297脚手架来开发新的GIRK1/2激活剂，并具有改进的通道亚型选择性曲线和脑培养剂所需的药代动力学特性，即体内探针。该项目结合了医学化学和复合表征的最先进方法，并将由一个调查团队进行，该团队在Girk渠道生物学和体内探针开发方面具有完全专业知识。这项工作是围绕三个特定目的构建的：1）开发潜力和选择性的GIRK1/2通道激活剂，2）开发具有优化的药代动力学特性的GIRK1/2通道激活剂，以及3）表征Vivo中GIRK1/2通道激活剂的药物型麦克相关特性。目标1和2中的工作将涉及迭代平行的医学化学合成和测试策略， 并将产生具有高于ML297的药效和药代动力学特性的GIRK1/2激活剂。在AIM 3中，这些化合物的体内效率，选择性和效力将在应力诱导的高温测试（SIH）测试中进行表征，这是一种具有抗焦虑化合物的面部有效性的范式。在此测试中表现出GIRK1/2依赖性有效性的一小部分优化问题将在另一个焦虑模型中进行进一步评估，并测试探讨GIRK1/2问题对运动活动和协调的影响。该研究项目的完成将为GIRK1/2渠道带来选择性和有效的体内问题。这些问题将促进对GIRK1/2渠道的相关性和治疗潜力的未来研究，包括对其对治疗的实用性的更严格评估 与动画有关的疾病。