Identification and Characterization of Small-Molecule IRF3-Dependent Immune Activators for Pharmaceutical...

Area of Science:

• Immunology
• Molecular Biology
• Drug Discovery

Background:

• Interferon regulatory factor 3 (IRF3) is a crucial transcription factor in the innate immune system.
• Activating IRF3 offers therapeutic potential for various diseases.
• Current methods for IRF3 activation are limited.

Purpose of the Study:

• To develop novel small-molecule activators of IRF3.
• To identify compounds that activate type I interferon responses with minimal NFκB activation.
• To elucidate the mechanism of IRF3 activation.

Main Methods:

• High-throughput screening of small-molecule libraries.
• Secondary screening and hit compound analysis.
• CRISPR-Cas9 knockout cell line screening to identify upstream pathways.
• Ex vivo cytokine release assays using human and mouse immune cells.

Main Results:

• Identified 399 initial hit compounds, with 142 candidates after secondary screening.
• Developed lead compounds with improved activity through chemical modifications.
• Demonstrated IRF3-dependent activation in human and mouse macrophages.
• Discovered a toll-interleukin-1 receptor-domain-containing-adapter-inducing interferon-β (TRIF)-dependent, TLR3/4-independent pathway for IRF3 activation.

Conclusions:

• Successfully developed small-molecule IRF3 activators with therapeutic potential.
• Identified a novel mechanism of IRF3 activation involving TRIF.
• These findings provide a foundation for developing new immunotherapies.