The IL-6 autocrine loop promoting IFN-γ-induced fibroblast senescence is involved in psychological stress-mediated exacerbation of vitiligo.

BACKGROUND

Psychological stress is the most common psychological comorbidity and a significant triggering factor of vitiligo. Moderate to severe psychological stress can markedly affect the efficacy of vitiligo treatment. However, the specific mechanisms underlying its involvement remain insufficiently studied.

METHODS

Chronic unpredictable mild stress (CUMS)-induced major depressive disorder (MDD)-like behavior was modeled in C57BL/6 mice alongside wild-type mice to investigate differences in vitiligo pathogenesis. White spot tissues from mouse tails were subjected to high-throughput transcriptomic sequencing (RNA-seq). In vitro experiments utilized β-galactosidase, P16, and P21 to assess IFN-γ-induced senescence. The effects of exogenous IL-6 on fibroblast senescence were assessed, and the role of blocking the IL-6 autocrine loop with an IL-6R inhibitor in reversing IFN-γ-induced fibroblast senescence was evaluated.

RESULTS

CUMS-induced MDD -like mice exhibited significantly lower body mass index and sugar-water preference index compared to wild-type mice, and their vitiligo severity was markedly increased. Transcriptomic sequencing revealed significant upregulation of cellular senescence and JAK-STAT signaling pathways in white spot tissues of depressive-like vitiligo mice. In vitro findings indicated that IFN-γ induced fibroblast senescence via activation of the JAK2-STAT3 signaling pathway, which subsequently promoted melanocyte apoptosis and increased IL-6 secretion and IL-6R expression. Exogenous IL-6 further activated the JAK2-STAT3 signaling pathway, induced fibroblast senescence, and synergistically intensified IFN-γ-induced fibroblast senescence.

CONCLUSION

Excessive activation of the IL-6 autocrine loop, synergizing with IFN-γ to aggravate fibroblast senescence and promote melanocyte apoptosis. Blocking the IL-6 autocrine loop may serve as an effective approach to mitigate the impact of CUMS on vitiligo pathogenesis and treatment efficacy.