High-throughput screening for Kv1.3 channel blockers using an improved FLIPR-based membrane-potential assay

Area of Science:

• Pharmacology
• Molecular Biology
• Biophysics

Background:

• Voltage-gated potassium (Kv) channels are crucial drug targets for numerous diseases.
• High-throughput screening (HTS) is a standard method for discovering compounds that modulate Kv channel activity.

Purpose of the Study:

• To develop and validate an improved fluorometric imaging plate reader (FLIPR) membrane potential assay for HTS of Kv1.3 channel modulators.
• To identify novel Kv1.3 channel blockers for potential therapeutic applications.

Main Methods:

• Optimization of a FLIPR membrane potential assay in Chinese hamster ovary (CHO) cells, including inhibition of endogenous transporters.
• High-throughput screening (HTS) campaign to identify Kv1.3 channel blockers.
• Confirmation of identified compounds using automated electrophysiology (IonWorks) and patch-clamp recording.

Main Results:

• The optimized FLIPR assay demonstrated robustness by accounting for endogenous transporters in CHO cells.
• HTS identified multiple chemical series of Kv1.3 channel blockers.
• Correlation between FLIPR and IonWorks assays was established, with some compounds showing nanomolar potency.

Conclusions:

• The improved FLIPR assay is effective for HTS and identification of Kv1.3 channel blockers.
• This assay facilitates the discovery of novel drug candidates targeting Kv1.3 channels.
• Both use-dependent and use-independent Kv1.3 channel blockers were identified, expanding the therapeutic potential.