Mechanistic Study of cGAS-STING Pathway–Induced Pyroptosis in Corneal Epithelial Cells in Keratoconjunctivitis Sicca

Xerophthalmia, also called Keratoconjunctivitis sicca (KCS), is often referred to as dry eye disease (DED).It is a chronic immune-mediated ocular surface inflammatory disease.Its characteristics are corneal epithelial cell damage and persistent local inflammation.Increasing evidence indicates that pyroptotic death of corneal epithelial cells can significantly exacerbate tissue damage and accelerate disease progression.The cyclic guanosine monophosphate-adenosine monophosphate synthase-interferon gene stimulator protein (cGAS-STING) pathway is a key DNAsensing signaling pathway in inflammatory cell death; however, its role in KCS is unclear.In this study, a KCS murine model was constructed in C57BL/6 mice, and different concentrations of H151 (a selective cGAS-STING inhibitor) were used for treatment.Human corneal epithelial cells (HCECs) were placed in an in vitro environment, first exposed to a hypertonic condition, and then treated with H151.The activity of the cGAS-STING pathway, pyroptosis, and the inflammatory response were evaluated by measuring tear secretion, performing TUNEL staining, using CCK-8, measuring LDH release, and using Western blotting (WB).In the DED mouse model, tear secretion decreased, corneal inflammatory cytokine expression increased, and cGAS-STING-related proteins were upregulated.Using H151 could significantly improve tear secretion, reduce pathological activity, and also reduce the quantity of TUNEL-positive cells and the level of caspase-3 and gasdermin E in a manner dependent on the dose.Similar to the in vivo experimental results, hypertonic stress activated the cGAS-STING pathway in HCECs, as evidenced by decreased cell viability, increased LDH release, and increased pyroptosis.H151 can enhance cell viability and inhibit the pyroptosis-related signaling pathway to alleviate these effects.The research results indicate that the cGAS-STING pathway is involved in the pyroptosis of corneal epithelial cells in Sjögren's syndrome and is closely associated with caspase-3/GSDME signaling.These findings suggest that cGAS-STING activation may contribute to pyroptotic processes rather than directly initiating caspase-3/GSDME-mediated pyroptosis.Accordingly, this pathway may represent a potential therapeutic target for DED.