Aspirin induces Nrf2‐mediated transcriptional activation of haem oxygenase‐1 in protection of human melanocytes from H(2)O(2)‐induced oxidative stress

The removal of hydrogen peroxide (H(2)O(2)) by antioxidants has been proven to be beneficial to patients with vitiligo. Aspirin (acetylsalicylic acid, ASA) has antioxidant activity and has great preventive and therapeutical effect in many oxidative stress‐relevant diseases. Whether ASA can protect human melanocytes against oxidative stress needs to be further studied. Here, we investigated the potential protective effect and mechanisms of ASA against H(2)O(2)‐induced oxidative injury in human melanocytes. Human melanocytes were pre‐treated with different concentrations of ASA, followed by exposure to 1.0 mM H(2)O(2). Cell apoptosis, intracellular reactive oxygen species (ROS) levels were evaluated by flow cytometry, and cell viability was determined by an Cell Counting Kit‐8 assay. Total and phosphorylated NRF2 expression, NRF2 nuclear translocation and antioxidant response element (ARE) transcriptional activity were assayed with or without Nrf2‐siRNA transfection to investigate the possible molecular mechanisms. Concomitant with an increase in viability, pre‐treatment of 10‐90 μmol/l ASA resulted in decreased rate of apoptotic cells, lactate dehydrogenase release and intracellular ROS levels in primary human melanocytes. Furthermore, we found ASA dramatically induced NRF2 nuclear translocation, enhanced ARE‐luciferase activity, increased both p‐ NRF2 and total NRF2 levels, and induced the expression of haem oxygenase‐1 (HO‐1) in human melanocytes. In addition, knockdown of Nrf2 expression or pharmacological inhibition of HO‐1 abrogated the protective action of ASA on melanocytes against H(2)O(2)‐induced cytotoxicity and apoptosis. These results suggest that ASA protects human melanocytes against H(2)O(2)‐induced oxidative stress via Nrf2‐driven transcriptional activation of HO‐1.