Astrocytic CCAAT/Enhancer-binding protein delta contributes to reactive oxygen species formation in neuroinflammation

Excessive reactive oxygen species (ROS) can form an oxidative stress and an associated neuroinflammation. However, the contribution of astrocytes to ROS formation, the cause of the resistance of astrocytes to oxidative stress, and the consequences on neurons remain largely uninvestigated. The transcription factor CCAAT/enhancer-binding protein delta (CEBPD) is highly expressed in astrocytes and has been suggested to contribute to the progress of Alzheimer's disease (AD). In this study, we found that ROS formation and expression of p47^phox and p67^phox, subunits of NADPH oxidase, were increased in AppTg mice but attenuated in AppTg/Cebpd^-/- mice. Cebpd can up-regulate p47^phox and p67^phox transcription via a direct binding on their promoters, which results in an increase in intracellular oxidative stress. In addition, Cebpd also up-regulated Cu/Zn superoxide dismutase (Sod1) in astrocytes. Inactivation of Sod1 increased the sensitization to oxidative stress, which provides a reason for the resistance of astrocytes in an oxidative stress environment. Taken together, the study first revealed and dissected the involvement of astrocytic Cebpd in the promotion of oxidative stress and the contribution of CEBPD to the resistance of astrocytes in an oxidative stress environment.