PANoptosis-CCL2 axis drives immune amplification in herpes simplex keratitis, identifying novel therapeutic targets

Herpes Simplex Keratitis (HSK), caused by HSV-1, is a leading cause of infectious blindness, characterized by significant immune-mediated corneal damage. While antiviral therapies effectively manage viral replication, they often fall short in mitigating the destructive inflammatory response, leading to recurrent disease and vision loss. Understanding the precise mechanisms of immune activation and programmed cell death (PCD) in the cornea is crucial for developing targeted anti-inflammatory strategies that complement antiviral treatment and preserve corneal integrity. This study investigates the role of PANoptosis, an integrated form of cell death, in HSK pathogenesis.

Researchers established a murine HSK model by infecting mice with HSV-1. Time-course RNA sequencing was performed on murine corneas at 0, 1, 3, 7, and 14 days post-infection to map temporal immune responses. Phenotypic and mechanistic analyses utilized quantitative real-time PCR, western blotting, immunofluorescence staining, flow cytometry, and co-culture experiments. Programmed cell death pathways were assessed using antagonists targeting PANoptosis, and the effects of a PANoptosis inhibitor or the CCL2 antagonist Bindarit were evaluated.

RNA sequencing revealed three sequential immune response phases in the cornea following HSV-1 infection: homeostasis disruption and transcriptional activation (days 0-3), immune amplification (days 3-7), and tissue reorganization (days 7-14). The immune amplification phase was strongly associated with the activation of three distinct programmed cell death pathways: apoptosis, pyroptosis, and necroptosis, culminating in PANoptosis. > PANoptosis was confirmed as a central mechanism in HSK pathogenesis, with Z-DNA-binding protein 1 (ZBP1) serving as a key driver of PANoptosome formation. Furthermore, PANoptosis in human corneal epithelial cells (HCECs) was shown to promote the release of C-C motif chemokine ligand 2 (CCL2), enhancing macrophage MHC-II and IFN-β expression and migration. The PANoptosis-CCL2/CCR2 axis was significantly upregulated in infected corneas and could be suppressed by a PANoptosis inhibitor or the CCL2 antagonist Bindarit.