Natural killer cells cooperate with neutrophils to suppress pathological angiogenesis in neovascular age-related macular degeneration

Neovascular age-related macular degeneration (nvAMD) is the leading cause of blindness in the elderly population associated with focal inflammation, however, understanding of the precise immune components governing this process is still limited. Here, we identified natural killer (NK) cells as a prominent lymphocyte population infiltrating the perivascular space of choroidal neovascularization (CNV) lesions. O-link analysis and single-cell RNA sequencing approaches identified CCR5-expressing NK cells is essential for further NK cell recruitment and extravasation in CNV site. NK cells suppress pathological angiogenesis via through clearance of senescent vasculatures, a process that requires neutrophil extracellular traps (NETs). Mechanistically, the release of NETs results from NKG2D-dependent NK cell activation and production of IFN-? at CNV lesions. Notably , age is the strongest risk factor for AMD to an aged immune system; our human and mouse data showed that aged NK cells exhibited compromised protective effects. Additionally, expansion of NK cells by IL-2 complex improved CNV formation. Collectively, our results revealed a previously unrecognized role of NK cells in suppressing nvAMD progression, suggesting these cells as a potential target for future immune therapies for patients with nvAMD. Overall design: To characterize the expression pattern of NK cell signature genes in the laser-induced photocoagulation mouse model of AMD (laser-induced CNV model), we performed RNA-sequencing of adult mouse retina-choroid complexes 3,7, and 14 days after laser burn and age-matched normal controls.To investigate the mechanisms underlying the protective effects of NK cells, we performed transcriptome analysis of the retina-choroid complex from Rag2-/- and Rag2-/-?c-/- mice three days after laser injury.