High Throughput Screening Identifies a Small Molecule Trafficking Corrector for Long-QT Syndrome Associated KCNQ1...

Area of Science:

• Cardiovascular Genetics
• Molecular Pharmacology
• Ion Channel Biology

Background:

• Congenital long QT syndrome (LQTS) increases the risk of fatal cardiac arrhythmias in young individuals.
• Pathogenic variants in the KCNQ1 gene, encoding a voltage-gated potassium channel, are a primary genetic cause of LQTS.
• Many KCNQ1 variants lead to loss-of-function due to improper channel trafficking to the cell membrane, with no current treatments targeting this defect.

Purpose of the Study:

• To identify small molecules capable of correcting the trafficking defects of KCNQ1 channels associated with LQTS.
• To evaluate the efficacy of identified compounds in restoring KCNQ1 channel function and cell surface expression.

Main Methods:

• High-throughput screening was employed to identify potential therapeutic small molecules.
• Cellular assays were used to assess the impact of identified compounds on KCNQ1 total and cell surface expression, trafficking efficiency, and current density.
• Analysis included evaluating effects on KCNQ1 transcription, degradation, and thermal stability.

Main Results:

• VU0494372 was identified as a small molecule that significantly increases total and cell surface expression of wildtype KCNQ1 and three LQTS-associated variants.
• Treatment with VU0494372 enhanced KCNQ1 trafficking efficiency and increased current density for wildtype and the V207M variant.
• The molecule did not affect KCNQ1 transcription, degradation, or thermal stability, suggesting a post-transcriptional mechanism.

Conclusions:

• Small molecules can be developed to enhance KCNQ1 expression and cell surface trafficking.
• VU0494372 represents a promising therapeutic candidate for LQTS by addressing the underlying molecular defect of impaired channel trafficking.
• This study introduces a novel pharmacological approach for the treatment of congenital long QT syndrome.