Pyroptosis Mediated by ROS/Caspase-3/GSDME Pathway in Aspergillus fumigatus-Induced Fungal Keratitis.

PURPOSE: Gasdermin E (GSDME), cleaved by (casp-3) activation, is known as a key executor in pyroptosis. However, its role in fungal keratitis (FK) remains unclear. Thus we analyzed the role of GSDME, as well as its signaling pathway in Aspergillus fumigatus (AF)-induced FK.

METHODS: We conducted experiments using a mouse model and human corneal epithelial cells. Initially, we infected mice with AF at various time intervals and examined the progression of FK lesions, selecting the time point with the most severe lesions. Next, we pre-treated the subjects with various cytokine inhibitors that may influence pyroptosis. We then assessed the development of FK lesions and the production of inflammatory cytokines using qRT-PCR, flow cytometry, transmission electron microscopy, as well as Western blotting.

RESULTS: The optimal stimulation time for corneal epithelial cells in mice and humans was determined to be three days and 12 hours, respectively. In both the mouse and corneal epithelial cell models, GSDME significantly mediated AF-induced pyroptosis downstream of the reactive oxygen species (ROS)/casp-3/GSDME pathway and greatly influenced the inflammatory process and keratitis in AF-induced FK.

CONCLUSIONS: Overall, GSDME played a crucial role in pyroptosis during corneal inflammation. By modulating IL-1β release during pyroptosis, GSDME had a significant impact on the host immune response in FK. This process could be inhibited by blocking the ROS/casp-3/GSDME pathway, potentially offering a novel treatment option for reducing corneal opacity in FK.