Melatonin Ameliorates Circadian Disruption-Associated Dry Eye via Modulation of BMAL1-REV-ERBα-IL-17 Axis and Ocular Surface Microbiota Homeostasis.

The association between modern lifestyle factors and dry eye disease (DED) pathogenesis has garnered increasing scientific attention. Emerging evidence implicates circadian disruption-a prevalent consequence of contemporary living patterns-as a significant yet not fully clarified pathogenic factor in DED development. To address this knowledge gap, we developed a circadian disruption mouse model using chronic jet lag exposure. Mice subjected to chronic jet lag exhibited conjunctival clock gene dysregulation and upregulated pro-inflammatory mediators, such as TNF-α, IL-6, and IL-17. Transcriptomic profiling demonstrated marked activation of IL-17-mediated inflammatory pathways within the conjunctival tissue. Therapeutic IL-17 neutralization substantially attenuated ocular surface inflammation, improved corneal epithelial integrity, and decreased apoptotic cell density in circadian disruption-induced dry eye mouse model. Moreover, REV-ERBα agonism potently suppressed IL-17 transcription, whereas BMAL1 deficiency exacerbated IL-17-driven inflammatory responses through REV-ERBα downregulation. Chronic jet lag additionally induced ocular surface microbiota dysbiosis, characterized by Firmicutes overproliferation. Melatonin administration effectively suppressed conjunctival IL-17 expression through BMAL1-REV-ERBα pathway activation while reducing the relative abundance of Firmicutes to restore ocular surface microbiota balance. Our study reveals that circadian disruption induces ocular surface inflammation through the BMAL1-REV-ERBα-IL-17 signaling axis and exacerbates dysbiosis of the ocular surface microbiota. Melatonin mitigates these pathological alterations via dual-directional modulation of circadian-immune signaling crosstalk and restoration of microbiota balance. Importantly, this study establishes melatonin as a multifaceted therapeutic agent for combating lifestyle-associated DED, while elucidating the underlying mechanisms governing circadian rhythm-microbiome axis dynamics in ocular surface pathogenesis.