Miller Melissa R., Zou Beiyan, Shi Jie, Flaherty Daniel P., Simpson Denise S., Yao Tuanli, Maki Brooks E., Day Victor W., Douglas Justin T., Wu Meng, McManus Owen B., Golden Jennifer E., Aubé Jeffrey, Li Min
University of Kansas Specialized Chemistry Center, Delbert M. Shankel Structural Biology Center, Lawrence KS 66047
University of Kansas, X-ray Crystallography Laboratory, Malott Hall, Lawrence, KS 66045
ML308 was identified as a novel inhibitor of the potassium channel, subfamily K, member 9 (KCNK9) two-pore domain potassium channel. Two-pore domain potassium channels provide a background leak conductance that is selectively permeable to potassium. These channels regulate cell membrane potential and excitability and thereby modulate a variety of processes including hormone secretion, proliferation, and central nervous system (CNS) function. A high throughput fluorescent screen measuring thallium influx through KCNK9 channels was used to identify bisamide and thiotriazole classes of inhibitors. Chemical modification of the thiotriazole scaffold yielded ML308 which displayed a potent block of KCNK9 channels in a thallium influx fluorescent assay (IC = 130 nM) and in an automated electrophysiology assay (IC = 413 nM). ML308 afforded >50-fold selectivity for block of KCNK9 over the closely-related, two-pore domain potassium channel, KCNK3, in fluorescent assays and displayed little or no block at 10 μM of the more distantly related potassium channels, Kir2.1, potassium voltage-gated channel, KQT-like subfamily, member 2 (KCNQ2), and human ether-a go-go-related gene (HERG). The potency and selectivity profile of ML308 makes it a useful pharmacological probe for studies of KCNK9 function and in further studies aimed at therapeutic intervention.
ML308被鉴定为钾通道亚家族K成员9（KCNK9）双孔结构域钾通道的新型抑制剂。双孔结构域钾通道提供对钾具有选择性通透性的背景泄漏电导。这些通道调节细胞膜电位和兴奋性，从而调节包括激素分泌、增殖和中枢神经系统（CNS）功能在内的多种过程。利用一种测量铊通过KCNK9通道内流的高通量荧光筛选方法来鉴定双酰胺和噻三唑类抑制剂。对噻三唑支架进行化学修饰得到了ML308，它在铊内流荧光测定法（IC = 130 nM）和自动电生理测定法（IC = 413 nM）中均表现出对KCNK9通道的有效阻断作用。在荧光测定中，与密切相关的双孔结构域钾通道KCNK3相比，ML308对KCNK9的阻断选择性超过50倍，并且在10 μM时对关系更远的钾通道Kir2.1、钾电压门控通道KQT样亚家族成员2（KCNQ2）和人类醚-去极化相关基因（HERG）几乎没有或没有阻断作用。ML308的效力和选择性特征使其成为研究KCNK9功能以及进一步进行治疗干预研究的有用药理学探针。
