Amelioration of Oxidative Stress in Melanocytes by Adipose-Derived Stem Cell Exosomes via the Keap1-Nrf2 Axis.
Abstract
Oxidative stress, particularly H₂O₂ accumulation, is a key pathogenic factor in vitiligo, yet therapies that directly protect melanocytes remain limited. Adipose-derived stem cell-derived exosomes (ADSC-Exos) are cell-free vesicles with reported antioxidant effects, but whether they act through the Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) pathway is unknown. This study aimed to investigate the protective effects of ADSC-Exos on hydrogen peroxide (H₂O₂)-induced oxidative damage in human melanocytes and to elucidate the underlying molecular mechanisms, focusing on the Keap1-Nrf2 signaling pathway. ADSCs and their exosomes were isolated and characterized using flow cytometry, transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blot. An oxidative stress model was established by treating PIG1 human melanocytes with H₂O₂. The therapeutic effects of ADSC-Exos were assessed by measuring cell viability, migration, intracellular ROS levels, DNA damage, and antioxidant enzyme activities. The involvement of the Keap1-Nrf2 pathway was examined by western blot and immunofluorescence. H₂O₂ treatment significantly induced oxidative stress in PIG1 cells, evidenced by reduced cell viability and migration, increased ROS accumulation, and elevated DNA damage. Treatment with ADSC-Exos markedly restored cellular functions. Mechanistically, ADSC-Exos downregulated the expression of Keap1, facilitated the nuclear translocation of Nrf2, and upregulated the expression of downstream antioxidant enzymes, including heme oxygenase 1 (HO-1) and glutathione peroxidase 4 (GPX4). The findings demonstrate that ADSC-Exos effectively ameliorate H₂O₂-induced oxidative damage in melanocytes. The cytoprotection is mediated through the activation of the Keap1-Nrf2-ARE signaling pathway. These findings support further investigation of ADSC-Exos as a potential therapeutic strategy for vitiligo.