HMOX1 and skin aging: In other words, when exposed to oxidative stress, Nrf2 dissociates from Keap1 and binds to antioxidant response element (ARE) to induce the expression of antioxidant-related enzymes, such as heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO1), and thereby inhibits ROS-induced oxidative damage and skin aging [9,10].