Z-Nucleic Acids: A Regulator of Macrophage PANoptosis and Fungal Biofilm in Fungal Keratitis.

Purpose: This study aimed to investigate the role of Z‑nucleic acids (Z‑NAs) in the pathogenesis of fungal keratitis (FK), focusing on its regulatory effects on fungal immune escape, inflammation, and biofilm activity. Methods: A mouse model of FK was established by the combination of stromal scrapes and corneal contact lens with Fusarium solani. Disease severity was assessed using clinical scoring and histopathological examination. In vitro, bone marrow-derived macrophages (BMDMs) were infected with F. solani, and the efficiency of fungal phagocytosis and escape by BMDMs was determined through fungal counting. The expression of Z‑DNA binding protein 1 (ZBP1)-PANoptosis markers in corneal tissues and BMDMs was detected by western blot, and the localization of Z-NAs in these samples was examined by immunofluorescence staining. Additionally, Z‑NA expression within in vitro fungal biofilms was detected by immunofluorescence, and its roles in modulating biofilm activity, antifungal drug resistance, and chemotactic ability were further characterized. Results: ZBP1-PANoptosis was significantly activated in FK corneal tissues and positively correlated with clinical severity in FK. F. solani infection triggered Z‑NA transformation and ZBP1-PANoptosis activation in BMDMs, which in turn promoted fungal immune escape and exacerbated inflammation. Z‑NAs accumulated as extracellular DNA in fungal biofilms and were shown to regulate biofilm activity, drug resistance, and chemotaxis. Conclusions: Z‑NAs play a dual pathogenic role in FK by inducing ZBP1-PANoptosis in macrophages and enhancing biofilm function, thereby promoting the progression of FK.