Modulating the voltage sensor of a cardiac potassium channel shows antiarrhythmic effects

Area of Science:

• Cardiovascular pharmacology
• Molecular cardiology
• Computational drug discovery

Background:

• Cardiac arrhythmias, particularly Torsade de Pointes, are a major cause of sudden cardiac death.
• Prolonged ventricular action potential duration (APD) is a key risk factor for these life-threatening arrhythmias.
• The slowly activating potassium current, I_Ks, is crucial for cardiac repolarization.

Purpose of the Study:

• To identify novel compounds that modulate I_Ks channel function.
• To investigate the potential of targeting the I_Ks voltage-sensing domain (VSD) for therapeutic intervention.
• To evaluate the efficacy of identified compounds in correcting drug-induced APD prolongation.

Main Methods:

• In silico screening of a chemical library using molecular docking to the I_Ks VSD.
• Electrophysiological assessment of compound effects on I_Ks VSD activation.
• Measurement of ventricular and atrial action potential duration (APD) in response to compound treatment.

Main Results:

• The compound C28 was identified through in silico screening.
• C28 specifically shifted I_Ks VSD activation to more negative voltages.
• C28 effectively reversed drug-induced APD prolongation without significantly altering normal APD in ventricles or atria.

Conclusions:

• Targeting the I_Ks VSD represents a promising therapeutic strategy for managing APD prolongation.
• C28 demonstrates potential for treating arrhythmias associated with prolonged APD.
• This approach may enhance the safety profile of existing drugs that can prolong APD.