Cyclosporine A Ameliorates Inflammatory Responses in Dry Eye by Inactivating cGAS-STING Signaling Via the Initiation of Autophagy.

PURPOSE: The purpose of this research was to examine the roles and regulatory mechanisms of autophagy and the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING) pathway in dry eye (DE) inflammation and the mechanism by which cyclosporine A (CsA) attenuates the inflammatory response in dry eye disease (DED) by modulating autophagy and the cGAS-STING pathway. METHODS: Two DE models, hypertonicity-stimulated human corneal epithelial (HCE-T) cells and benzalkonium chloride (BAC)-treated C57BL/6 mice, were established to investigate the modulation of autophagy and the cGAS-STING pathway by CsA in DE. Changes in light chain 3 (LC3), P62, γ-H2AX, cGAS, and STING levels were detected via western blotting. Reverse-transcription quantitative PCR was used to detect changes in IL-6 and IL-1β mRNA levels after drug administration, and autophagosomes were observed via electron microscopy. The autophagy inhibitor 3-methyladenine (3-MA) was used to further clarify the effects of autophagy on the cGAS-STING pathway. Hematoxylin and eosin staining and corneal fluorescence staining were used to assess the signs of DE in the mice. RESULTS: Autophagy and the cGAS-STING pathway were significantly activated in hypertonicity-stimulated HCE-T cells and in the BAC-induced DE model. CsA activated autophagy and decreased the levels of γ-H2AX, cGAS, STING, IL-6, and IL-1β in the DE models. The autophagy inhibitor 3-MA reversed the inhibitory effects of CsA on the cGAS-STING pathway and the inflammatory response. Similarly, in vivo experiments revealed that CsA activated autophagy, inhibited the expression of components of the cGAS-STING pathway, promoted the restoration of corneal epithelial cell morphology, and reduced corneal fluorescence staining scores in mice with DE. CONCLUSIONS: CsA inhibited the cGAS-STING pathway by activating autophagy, further reducing inflammation in DE models and attenuating the signs of DE in mice.