Figure 5.

Neurons release ANG to signal their need for protection to astrocytes. A, pre-exposing cortical neurons to H₂O₂ (1 μm) caused the release of ANG. A zymogram gel of conditioned medium from stressed neurons revealed a high level of active ANG (4.0 μg/ml) compared with that from normal neurons (0.5 μg/ml). B, neurons were protected by conditioned medium collected from astrocytes that were pre-exposed to WT ANG (5 μg/ml). Three or more biological replicates were performed for each experiment. Protection depended on Nrf2 and the ribonucleolytic activity of ANG. Significant cell death compared with Nrf2^−/− astrocytes is marked by asterisks, where ** refers to p ≤ 0.01 and *** refers to p ≤ 0.001.