A “Target Class” Screen to Identify Activators of Two-Pore Domain Potassium (K2P) Channels

Abstract

Two-pore domain potassium (K2P) channels carry background (or leak) potassium current and play a key role in regulating resting membrane potential and cellular excitability. Accumulating evidence points to a role for K2Ps in human pathophysiologies, most notably in pain and migraine, making them attractive targets for therapeutic intervention. However, there remains a lack of selective pharmacological tools. The aim of this work was to apply a “target class” approach to investigate the K2P superfamily and identify novel activators across all the described subclasses of K2P channels. Target class drug discovery allows for the leveraging of accumulated knowledge and maximizing synergies across a family of targets and serves as an additional approach to standard target-based screening. A common assay platform using baculovirus (BacMam) to transiently express K2P channels in mammalian cells and a thallium flux assay to determine channel activity was developed, allowing the simultaneous screening of multiple targets. Importantly, this system, by allowing precise titration of channel function, allows optimization to facilitate the identification of activators. A representative set of channels (THIK-1, TWIK-1, TREK-2, TASK-3, and TASK-2) were screened against a library of Food and Drug Administration (FDA)-approved compounds and the LifeArc Index Set. Activators were then analyzed in concentration–response format across all channels to assess selectivity. Using the target class approach to investigate the K2P channels has enabled us to determine which of the K2Ps are amenable to small-molecule activation, de-risk multiple channels from a technical point of view, and identify a diverse range of previously undescribed pharmacology.

Overexpressed KCNK1 regulates potassium channels affecting molecular mechanisms and biological pathways in bladder cancer

“…Potassium two pore domain channel subfamily K member 1 (KCNK1) is a widely expressed pH-gated two pore structural domain potassium channel, often encoding TWIK-1 or K2P1 protein[ 12 , 13 ]. KCNK1 plays an important role in physiological and pathological functions associated with changes in electrical membrane potential by controlling the efflux of potassium ions to maintain the balance of the resting potential of the cell membrane [ 14 , 15 ]. Previous research indicated that KCNK1 plays a very vital role in promoting tumour cell malignant transformation, especially in regulating cell cycle progression and cancer cell malignant proliferation and migration [ 16 ].…”

Multiple Effects of Echinochrome A on Selected Ion Channels Implicated in Skin Physiology

“…Furthermore, the siRNA knock-down of TREK-2 increased pain behaviors under skin inflammation [ 58 ]. TRAAK knockout mice also showed sensitivity to mechanical and heat stimuli [ 59 ] and postsurgical neuropathic pain [ 60 ].…”

“…These findings suggest that the TREK channels could be attractive targets for the development of novel therapeutics. Despite the recent development of activators and inhibitors targeting the TREK channels [ 60 ], further investigation of the potent and/or selective pharmacological tools for the TREK channels is awaited [ 26 ]. In this respect, although not a direct activator by itself, the strong facilitation by Ech A suggests a novel type of pharmacological tool for modulating the TREK channels.…”