Role of NR4A1 and non-classical monocytes in a mouse model of neovascular age-related macular degeneration
Neovascular AMD (nAMD) causes vision loss from destructive angiogenesis, termed choroidal neovascularization (CNV). Cx3cr1-/- mice display non-classical monocyte and microglia alterations, and increased CNV size, suggesting that non-classical monocytes may inhibit CNV formation. While Nr4a1-/- mice are deficient in non-classical monocytes, results are confounded by macrophage hyper-activation. Nr4a1se2/se2 mice lack a transcriptional activator, resulting in non-classical monocyte loss, without macrophage hyper-activation. We subjected Nr4a1-/- and Nr4a1se2/se2 mice to the laser-induced CNV model and performed multi-parameter flow cytometry. We found that both models lack non-classical monocytes, but only Nr4a1-/- mice displayed increased CNV area. Additionally, CD11c+ macrophages were increased in Nr4a1-/- mice. Single-cell transcriptomic analysis uncovered that CD11c+ macrophages were enriched from Nr4a1-/- mice and expressed a pro-angiogenic transcriptomic profile that was disparate from prior reports of macrophage hyper-activation. These results suggest that non-classical monocytes are dispensable during laser-induced CNV, and NR4A1 deficiency shifts the transcriptional profile toward a pro-angiogenic phenotype. Overall design: Ocular CD45+ immune cells were isolated by FACS and scRNA-seq was performed on sham and laser-treated wildtype and Nr4a1-/- eyes.