The antioxidant response element and oxidative stress modifiers in airway diseases

Redox balance is particularly important in the airways because they are the first points of contact with environmental pollutants such as ozone, particles, and cigarette smoke, as well as pathogens such as bacteria and viruses. However, an imbalance between toxicant-induced reactive oxygen (ROS) and nitrogen (RNS) species and the antioxidant defense system leads to oxidative stress, which has been implicated in the development and/or perpetuation of airway diseases, including malignancy. Various antioxidant enzymes and proteins are critical to maintaining the reducing environment of the cell and preventing the damage to various biomolecules that is elicited by ROS/RNS. Emerging evidence indicates that transcriptional activation of the antioxidant response element (ARE) plays a crucial role in modulating oxidative stress and providing cytoprotection against prooxidant stimuli. This review focuses on the regulation and functional roles of key effectors that bind to the ARE and differentially (up- or down-) regulate gene expression in lung tissue/cell types in response to respiratory toxicants. It also provides a perspective on whether boosting ARE-mediated gene expression with dietary plants and synthetic plant products will offer a better therapeutic strategy for mitigating oxidative stress and respiratory pathogenesis.