Development of an automated screen for Kv7.2 potassium channels and discovery of a new agonist chemotype

• Published in: Bioorganic & medicinal chemistry letters 2022-09, Vol.71, p.128841-128841, Article 128841
• Main Authors: Hernandez, Ciria C., Tarfa, Rahilla A., Miguel I. Limcaoco, Jose, Liu, Ruiting, Mondal, Pravat, Hill, Clare, Keith Duncan, R., Tzounopoulos, Thanos, Stephenson, Corey R.J., O'Meara, Matthew J., Wipf, Peter
• Format: Article
• Language: English
• Subjects: Agonists; KCNQ Potassium Channels - genetics; KCNQ Potassium Channels - metabolism; KCNQ2 Potassium Channel - genetics; KCNQ2 Potassium Channel - metabolism; Potassium channels; Quinolines; SyncroPatch screen; Voltage-dependent activation
• ISSN: 0960-894X; 1464-3405
• DOI: 10.1016/j.bmcl.2022.128841

[Display omitted] To identify pore domain ligands on Kv7.2 potassium ion channels, we compared wild-type (WT) and W236L mutant Kv7.2 channels in a series of assays with previously validated and novel agonist chemotypes. Positive controls were retigabine, flupirtine, and RL-81; i.e. Kv7.2 channel activators that significantly shift voltage-dependent activation to more negative potentials (ΔV50) at 5 µM. We identified 6 new compounds that exhibited differential enhancing activity between WT and W236L mutant channels. Whole cell patch-clamp electrophysiology studies were conducted to identify Kv7.2. Kv7.2/3, Kv7.4, and Kv7.5 selectivity. Our results validate the SyncroPatch platform and establish new structure activity relationships (SAR). Specifically, in addition to selective Kv7.2, Kv7.2/3, Kv7.4. and Kv7.5 agonists, we identified a novel chemotype, ZK-21, a 4-aminotetrahydroquinoline that is distinct from any of the previously described Kv7 channel modifiers. Using flexible receptor docking, ZK-21 was predicted to be stabilized by W236 and bind perpendicular to retigabine, burying the benzyl carbamate group into a tunnel reaching the core of the pore domain.