FUNCTIONAL ANALYSIS OF BIPARTITE NRF2 ACTIVATORS THAT OVERCOME FEEDBACK REGULATION FOR AGE-RELATED CHRONIC DISEASES

Area of Science:

• Biochemistry
• Molecular Biology
• Neuroscience

Background:

• Nuclear factor erythroid 2-related factor 2 (Nrf2) activation is a therapeutic strategy for aging, oxidative stress, inflammation, and neurodegeneration.
• Keap1 regulates Nrf2 stability by targeting it for proteasomal degradation; current activators modify Keap1 thiols or displace Nrf2.
• Displacement activators lose potency in cell-based assays due to high Keap1 concentrations and competition with endogenous proteins.

Purpose of the Study:

• To address the potency loss of Nrf2 displacement activators in cell-based assays.
• To develop a specific Nrf2 activator with potential for continuous administration and reduced side effects.
• To explore novel strategies for treating age-related neurodegeneration by targeting both Nrf2 and Bach1.

Main Methods:

• Investigated the cause of potency loss for Nrf2 displacement activators in cell-based assays.
• Designed and analyzed a cell-permeable Nrf2 peptide with an alkylating fumarate moiety.
• Utilized transcriptomic analysis to confirm selective Nrf2 pathway activation.
• Evaluated the heterocyclic carboxamide HPPE for Nrf2 activation and Bach1 inhibition properties.

Main Results:

• High micromolar concentrations of Keap1 in cells and tissues explain the reduced potency of displacement activators.
• A fumarate-linked Nrf2 peptide selectively activated the Nrf2 genetic program, demonstrating targeted specificity.
• HPPE demonstrated combined Nrf2 activation and Bach1 inhibition, bypassing feedback regulation.

Conclusions:

• Targeted delivery of alkylating agents to Keap1 offers a specific approach to Nrf2 activation.
• HPPE represents a promising bipartite activator with dual Nrf2 and Bach1 targeting capabilities.
• HPPE holds potential for optimization in treating age-related neurodegenerative disorders.