Behçet's uveitis (BU) is a severe ocular manifestation of Behçet's disease, typically accompanied by abnormal neutrophil infiltration and hyperactivation. However, the underlying causes of excessive neutrophil extracellular traps (NETs) production and mechanisms by which NETs contribute to the pathogenesis of BU remain incompletely understood. Neutrophils from BU patients exhibit a higher propensity for NETs release compared to healthy controls. In the experimental autoimmune uveitis (EAU), neutrophils are observed to exert pro‐inflammatory effects through NETs. Clearing NETs can inhibit T helper 17 (Th17) cell differentiation and significantly alleviate EAU symptoms. In vivo and in vitro experiments demonstrate neutralizing IL‐17A markedly reducing neutrophil infiltration and NETs formation in EAU. Single‐cell RNA sequencing confirms that CD44 plays a key role in mediating interactions between NETs and Th17 cells. Antagonizing CD44 inhibits the proportion of Th17 cells and NETs formation. Multiplex immunofluorescence and cell communication analyses further demonstrate interactions and colocalization between NETs and CD44highCD4+T cells in EAU. NETs induce Th17 differentiation via upregulating CD44, and in turn, Th17 cells secrete IL‐17A to recruit neutrophils and promote NETs formation. Interrupting NETs‐CD44‐IL‐17A feedback loop may be a potential therapeutic target for BU.
Inflammation-induced angiogenesis is closely related to many diseases and has been regarded as a therapeutic target. Caspase-8 has attracted increasing attention for its immune properties and therapeutic potential in inflammatory disorders. The aim of our study is to investigate the clinical application of pharmacological inhibition of caspase-8 and the underlying molecular mechanisms in inflammation-induced angiogenesis in the cornea. A model of alkali burn (AB)-induced corneal neovascularization (CNV) in C57BL/6 wild-type (WT) mice and toll-like receptor 4 knockout (Tlr4-/-) mice was used. We found that AB increased caspase-8 activity and the pharmacological inhibition of caspase-8 exerted substantial inhibitory effects on CNV, with consistent decreases in caspase-8 activity, inflammatory cell infiltration, macrophage recruitment and activation, VEGF-A, TNF-α, IL-1β, MIP-1, and MCP-1 expression in the cornea. In vitro, caspase-8 mediated TLR4–dependent chemokines and VEGF-A production by macrophages. The TLR4 knockout significantly alleviated CNV, suppressed caspase-8 activity and downregulated expression of inflammatory cytokines and chemokines after AB. Taken together, these findings provide the first demonstration that the pharmacological inhibition of caspase-8 suppresses inflammation-induced angiogenesis and support the use of a pharmacological caspase-8 inhibitor as a novel clinical treatment for CNV and other angiogenic disorders.