A cell-active cyclic peptide targeting the Nrf2/Keap1 protein-protein interaction

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• The Nrf2/Keap1 protein-protein interaction (PPI) is a key target for combating oxidative stress in various diseases.
• Peptides offer a potential therapeutic strategy for inhibiting this PPI, complementing small molecules.

Purpose of the Study:

• To develop a novel peptide stapling strategy for targeting the Nrf2/Keap1 PPI.
• To create constrained and functionalized peptides with improved activity and cellular efficacy.

Main Methods:

• A two-component peptide stapling approach was employed.
• Peptides were functionalized, including with a fatty acid tag (P8-H).
• Binding affinity, cellular activity (ARE gene transcription), and structural analysis (crystallography) were assessed.

Main Results:

• The P8-H peptide demonstrated nanomolar affinity for Keap1.
• It effectively induced ARE gene transcription in a human lung epithelial cell line at sub-micromolar concentrations.
• High-resolution crystal structure of the peptide-Keap1 complex was obtained.

Conclusions:

• The peptide stapling strategy successfully generated potent Nrf2/Keap1 PPI inhibitors.
• The P8-H peptide represents a promising lead compound for therapeutic development.
• The obtained crystal structure aids in designing cell-permeable peptidomimetic inhibitors.