COPD lung studies of Nrf2 expression and the effects of Nrf2 activators

Area of Science:

• Pulmonary Medicine
• Cellular Biology
• Pharmacology

Background:

• Nuclear factor erythroid 2-related factor 2 (Nrf2) governs antioxidant defenses in lung cells, including epithelial cells and alveolar macrophages (AM).
• The Nrf2/Keap-1 pathway is a target for modulators, including electrophilic compounds and protein-protein interaction (PPI) inhibitors.
• This study investigated Nrf2 and Keap-1 levels in COPD patients and the impact of Nrf2 activators on COPD AM.

Purpose of the Study:

• To assess Nrf2 and Keap-1 protein and gene expression in lung tissue and isolated AM from COPD patients compared to controls.
• To evaluate the effects of various Nrf2 activators on antioxidant gene expression and activity in COPD AM.

Main Methods:

• Analysis of Nrf2 and Keap-1 expression in lung tissue and isolated AM from non-smokers, smokers, and COPD patients using immunohistochemistry and qPCR.
• Culture of AM with Nrf2 activators (CDDO, C4X_6665, GSK7, MMF, Sulforaphane) to assess Nrf2 target gene expression and NQO1 activity.

Main Results:

• Nrf2 and Keap-1 expression remained unchanged in COPD epithelium and AM compared to controls.
• NQO1 activity was reduced, while NQO1, HMOX1, SOD1, and TXNRD1 gene expression increased in COPD patients.
• All tested Nrf2 activators upregulated NQO1 activity and target gene expression in AM from COPD and smoker groups, with C4X_6665 showing superior potency.

Conclusions:

• Evidence suggests Nrf2 signaling pathway dysregulation in AM from COPD patients.
• The novel PPI Nrf2 compound C4X_6665 exhibits higher potency in inducing antioxidant activity and gene expression compared to electrophilic compounds.
• C4X_6665 holds significant therapeutic potential for addressing Nrf2 pathway dysregulation in COPD AM.