An HTS to Discover Novel Modulators of the GIRK 2/3 Potassium Channel

产品说明： 离子通道在体内的每个细胞中表达，并参与关键和不同的生理过程，包括快速神经传递，建立和维持心律以及溶质平衡。离子通道功能的重要性和多样性导致了离子通道相关的病理学以及许多离子通道靶向治疗。虽然离子通道在过去的三十年里一直是密集研究的目标，但关于特定离子通道在正常生理过程和疾病中的作用仍有许多有待了解。我们缺乏对特定离子通道过程的作用的理解的一个重要原因是缺乏针对这些通道的有效的和选择性的药理学工具。G蛋白偶联内向整流钾离子通道（GIRK）是近二十年来一直是研究焦点的离子通道家族的主要例子，被认为是从房颤到镇痛的许多适应症的潜在靶点。然而，只有一种非常有效的 和选择性GIRK抑制剂，而没有有效和选择性GIRK激活剂。GIRK由四个亚基（GIRK 1-4）的同源和异源组合组成。这些亚基在CNS和外周的许多组织中表达。最近，我们已经使用基于铊（Tl+）通量的筛选来发现由GIRK 1/2亚基组成的GIRK通道的第一个有效的和选择性的激活剂。令人惊讶的是，迄今为止评估的约100种GIRK 1/2激活剂中没有一种对不含GIRK 1的GIRK（GIRK 2，GIRK 2/3）显示出任何活性。因此，我们建议进行高通量筛选，以发现GIRK 2/3亚基组合的第一个选择性激活剂。与含GIRK 1的GIRK相比，GIRK 2和GIRK 2/3亚基组合在中脑结构如腹侧被盖区（VTA）和离散的亚细胞定位中具有相对受限的表达模式。虽然有研究表明这些通道与奖赏和成瘾相关的回路有关，但由于缺乏选择性药理学工具，大多数对GIRKs作用的理解仍然不确定。基于我们使用基于T1+通量的高通量筛选发现GIRK 1/2的小分子调节剂的成功，我们提出筛选160，000个样品化合物集合，并使用一组开发良好的验证性、作用机制和选择性筛选来表征命中，所述筛选被设计为鉴定具有被开发为亚基选择性GIRK探针的能力的化合物。这些探针将立即用于开始理解GIRK 1和不含GIRK 1的GIRK之间的作用机制和选择性。这些探针还将作为体内探针开发的候选者，以使GIRK在生理学中的作用的研究和其治疗潜力的探索成为可能，包括成瘾性疼痛和癫痫。

DESCRIPTION: Ion channels are expressed in every cell in the body and are involved in critical and diverse physiological processes including fast neurotransmission, establishing and maintaining cardiac rhythms, and solute balance. The importance and diversity of ion channel function results both in ion channel-related pathologies but also in a number of ion channel-targeted therapies. Though ion channels have been the targets of intense research over the last three decades, much remains to be understood regarding the roles of specific ion channels in normal physiological processes and disease. A substantial reason for our lack of understanding of the roles of specific ion channels process is the lack of potent and selectively pharmacological tools targeting these channels. The G-protein Coupled Inward Rectifying Potassium K+ Channels (GIRK) are prime examples of an ion channel family that has been the focus of research for nearly two decades and are thought to be potential targets for numerous indications spanning from atrial fibrillation to analgesia. However, there is but one highly potent and selective GIRK inhibitor and no potent and selective GIRK activators. GIRKs are comprised of homo and heteromeric combinations of four subunits (GIRK 1-4). These subunits are expressed in numerous tissues in the CNS and the periphery. Very recently we have used thallium (Tl+) flux- based screening to discover the first potent and selectively activators of a GIRK channel comprised of GIRK1/2 subunits. Surprisingly, none of the ~ 100 GIRK 1/2 activators evaluated thus far shows any activity at non-GIRK 1 containing GIRKs (GIRK 2, GIRK 2/3). Thus, we propose to perform a high-throughput screen to discover the first selective activators of the GIRK 2/3 subunit combination. The GIRK 2 and GIRK2/3 subunit combinations have a relatively restricted expression pattern in mid-brain structures such as the ventral tegmental area (VTA) and discrete subcellular localization compared to GIRK 1-containing GIRKs. Though there is building research that implicates these channels in reward and addiction-related circuitry, most of understanding of GIRKs role remains uncertain due to the lack of selective pharmacological tools. Building upon our success in discovering small molecule modulators of GIRK 1/2 using Tl+ flux-based high-throughput screening, we are proposing to screen a 160,000 sample compound collection and characterize hits using a well-developed set of confirmatory, mechanism of action, and selectivity screens designed to identify compounds with the capacity to be developed as subunit-selective GIRK probes. These probes will be immediately useful to begin understanding mechanisms of action and selectivity between GIRK 1 and non-GIRK1 containing GIRKs. These probes will also advance as candidates for in vivo probe development to enable the investigation of GIRK's roles in physiology and exploration of its therapeutic potential for a variety of important indications including addiction pain, and epilepsy.