The Formation of Melanocyte Apoptotic Bodies in Vitiligo and the Relocation of Vitiligo Autoantigens under Oxidative Stress

Abstract

Background. Oxidative stress has a vital role in the early stages of vitiligo. Autoantigens released from apoptotic melanocytes (MC) under oxidative stress are involved in the presentation and recognition of antigens. However, the transport of autoantigens to the cell surface and their release to the extracellular environment are still unclear. Apoptotic bodies (ABs) have always been considered as a key source of immunomodulators and autoantigens. Yet, the role of ABs in the immune mechanism of vitiligo is still unknown. Purpose. To explore whether MC’s autoantigens translocate into ABs during oxidative stress-induced apoptosis and study the molecular mechanisms underlying autoantigen migration and AB formation. Methods. PIG3V (an immortalized human vitiligo melanocyte cell line) were treated with H2O2, and ABs were separated. Transmission electron microscopy, flow cytometry, Western blot, mass spectrometry, and other methods were used to determine the relocation of specific antigens in PIG3V cells to ABs. After pretreatment with specific inhibitors (Rho kinase (Y-27632), myosin light chain kinase (MLCK, ML-9), pan-caspase (zVAD-FMK), and JNK (SP600125)), the pathway of autoantigen translocation into ABs and the formation of apoptotic bodies were determined. Results. When treated with 0.8 mM H2O2, ABs were released from these cells. Autoantigens such as tyrosinase-related protein 1 (TYRP-1) and cleavage nuclear membrane antigen Lamin A/C (Asp230) were concentrated in ABs. The expression of autoantigens and the formation of ABs increased in a time- and dose-dependent manner after treatment with H2O2, while the application of specific inhibitors inhibited the formation of apoptotic bodies, i.e., the expression of antigens. Conclusion. Vitiligo autoantigens translocate into ABs in the process of apoptosis induced by oxidative stress. The cytoskeletal protein activation pathway and the JNK-related apoptosis pathway are involved in the transport of autoantigens and the formation of ABs. ABs may be the key bridge between MC cell apoptosis and cellular immunity.

Transcutaneous Auricular Vagus Nerve Stimulation Alleviates Monobenzone-Induced Vitiligo in Mice

“…However, after taVNS, the MDA concentration significantly decreased, and SOD and CAT activities were restored ( p < 0.05). Oxidative stress can induce apoptosis of melanocytes in the skin, resulting in reduced tyrosinase synthesis in apoptotic melanocytes [ 21 , 22 ]. We measured the level of tyrosinase in mouse skin, and the results showed a significant reduction in tyrosinase content in the skin of vitiligo mice.…”

Targets Exploration of Hydroxychloroquine for Pigmentation and Cell Protection Effect in Melanocytes: The Clue for Vitiligo Treatment

“…The Human vitiligo melanocyte cell line PIG3V was a gift from Professor Chunying Li (Xijing Hospital of Air Force Medical University, Xi’an, China) and cultured (2×10 5 cells/mL) in a 6-well plate (2mL/well) supplemented with DMEM/F12, 10% FBS, basic fibroblast growth factor (10ng/mL), phorbol myristate acetate (10ng/mL), and penicillin/streptomycin (10000U/mL, 10000μg/mL) at 37°C in 5% CO 2 for 24 hours. 30 The cultured PIG3V cells were randomly divided into an HCQ group and a control group. Cells in the HCQ group were treated with 1μg/mL HCQ (Sigma-Aldrich Corp., St. Louis, MO, USA) for 24 hours.…”

The Role of Oxidative Stress in Vitiligo: An Update on Its Pathogenesis and Therapeutic Implications

“…Taken together, these findings suggest the involvement of the TNF-α/TNFR pathway and IFN-γ pathway in melanocyte apoptosis of vitiligo. Current studies have found that tyrosinase-related protein (TYRP-1) and cleavage nuclear membrane antigen Lamin A/C (Asp230) can translocate into the apoptotic bodies of melanocytes [ 57 ]. The formation of melanocyte apoptotic bodies in vitiligo is mediated by the cytoskeletal protein activation pathway and the JNK-related apoptosis pathway [ 57 ].…”

“…Current studies have found that tyrosinase-related protein (TYRP-1) and cleavage nuclear membrane antigen Lamin A/C (Asp230) can translocate into the apoptotic bodies of melanocytes [ 57 ]. The formation of melanocyte apoptotic bodies in vitiligo is mediated by the cytoskeletal protein activation pathway and the JNK-related apoptosis pathway [ 57 ]. This study links melanocyte apoptosis and cellular immunity in vitiligo pathogenesis.…”