Impaired activation of the Nrf2-ARE signaling pathway undermines H 2 O 2-induced oxidative stress response: A possible mechanism for melanocyte degeneration in vitiligo

Abstract

Vitiligo melanocytes possess higher susceptibility to oxidative insults. Consistent with this, impairment of the antioxidant defense system has been reported to be involved in the onset and progression of vitiligo. Our previous study showed that the nuclear factor E2-related factor 2-antioxidant response element (Nrf2-ARE) pathway and its downstream antioxidant enzyme heme oxygenase-1 (HO-1) are crucial for melanocytes to cope with H 2 O 2-induced oxidative damage. Here, we sought to determine whether the diminished Nrf2-ARE activity that contributes to reduced downstream antioxidant enzymes and increased oxidative stress could be the reason why melanocytes are more vulnerable to vitiligo. We found that vitiligo melanocytes exhibited hypersensitivity to H 2 O 2-induced oxidative injury because of reduced Nrf2 nuclear translocation and transcriptional activity, which led to decreased HO-1 expression and aberrant redox balance. Moreover, we also found that the level of serum HO-1 was significantly decreased and that of IL-2 was markedly increased in 113 vitiligo patients when compared with healthy controls. These data demonstrate that impaired activation of Nrf2 under oxidative stress could result in decreased expression of antioxidant enzymes and increased death of vitiligo melanocytes. © 2014 The Society for Investigative Darmatology.