Figure 1. Fate Mapping Reveals Ontogeny, Longevity and Phenotype of Retinal Microglia.

(A) Schematic showing the anatomy of the eye.

(B) Flow cytometry plots depict yolk-sac derived microglia in retina. Pregnant Runx1^MCreM; Rosa^R26R-eYFP mice received tamoxifen 4’OHT at E7.5 days. Tissues were collected from 8 wk old progeny for flow cytometry.

(C) Dot plots (mean ± SEM) summarize the percentage of Runx1-YFP⁺ microglia shown in (B) from 2 independent experiments. Each dot represents one mouse (n = 4 to 6 per group).

(D) Representative images show distribution of short-lived (fGFP⁻) and long-lived (fGFP⁺) macrophages. Adult Cx3cr1^Cre-ER; Rosa^R26R-fGFP mice received tamoxifen and collected 1 yr later. (outer and inner nuclei layer, ONL and INL; outer and inner plexiform layer, OPL and IPL; ganglion cell layer, GCL; ciliary body, CB; Optic N, nerve). Choroid layer boundary is delineated (white lines). Scale bars, 100 μm.

(E, F) Adult Cx3cr1^Cre-ER; Rosa^P26R-fGFP mice received tamoxifen and tissues collected at 48 hrs (baseline) and 1 yr. Representative flow cytometry plots of macrophages at 1-yr post or control (E). Representative dot plots compare the percentage of fGFP⁺ macrophages between 48-hr and 1-yr (F) from 2 independent experiments. Grey areas (mean ± SD) show the percentage of control (n=9 eye tissues). Each dot represents one mouse (n = 6 per group).

(G, H) tSNE clustering of long- and short-lived macrophages (G) and tissue specificity of long-lived macrophages (H).

See also Figure S1.