Small-molecule compounds boost genome-editing efficiency of cytosine base editor

Area of Science:

• Molecular Biology
• Gene Editing Technologies
• Drug Discovery

Background:

• Cytosine base editors (CBEs) offer precise C-to-T conversion for therapeutic potential.
• Current CBE efficiency limitations hinder widespread clinical application.

Purpose of the Study:

• To develop a high-throughput system for measuring CBE activity.
• To identify small molecules that enhance CBE efficiency in human cells.

Main Methods:

• A human cell-based reporter system was utilized for high-throughput screening.
• 1813 small-molecule compounds were screened for their ability to enhance CBE activity.
• The efficacy of identified compounds was validated across multiple CBE variants and in disease models.

Main Results:

• Ricolinostat and Nexturastat A, both HDAC6 inhibitors, significantly improved BE3 editing efficiency (2.45- to 9.95-fold).
• These inhibitors enhanced activity across various CBE variants (BE4max, YE1-BE4max, evoAPOBEC1-BE4max, SpRY-CBE4max).
• Combined application of BE3 and Ricolinostat corrected a pathogenic ABCA4 mutation (>3-fold increase) and facilitated generation of disease models.

Conclusions:

• HDAC6 inhibitors Ricolinostat and Nexturastat A effectively enhance CBE activity in human cells.
• This strategy improves the efficiency and applicability of CBE for therapeutic development and disease modeling.
• The developed reporter system provides a valuable tool for accelerating the discovery of CBE enhancers.