Myeloid progenitors differentiate into microglia and promote vascular repair in a model of ischemic retinopathy
J. Clin. Invest. Matthew R. Ritter, et al. 116:3266 doi:10.1172/JCI29683 [Go to this article.]

Figure 5
Intravitreally injected CD44^hi cells take on characteristics of retinal microglia. (A) Transplanted CD44^hi cells (green) injected at P7 localized to and survived within the avascular central retina at P12. Many cells labeled with GS lectin (red), which labels microglia in the retina, and thus appear yellow. (B) CD44^hi cells (green, arrowhead) often assumed a ramified morphology similar to endogenous microglia. Endogenous microglia (arrow) and retinal vessels were stained with GS lectin (red). (C–F) In addition to the intervascular localization shown in B, transplanted CD44^hi cells also assumed a perivascular localization and were positive for F4/80 (C) and CD11b (E), markers of macrophages/microglia. D and F are merges with GFP expression (green), GS lectin (blue), and F4/80 (red, D) or CD11b (red, F). (G) CD44^hi cells assumed both perivascular and intervascular localization (3D image). Note the ramified, microglia-like morphology of the GFP⁺ cells. (H and I) CD44^hi cells did not form any portion of the vessel lumen, as shown by 3D imaging. The image in H was rotated such that the vessel could be viewed in cross-section. (I) Numbered positions indicated in H show that the GFP⁺ cell (green) was found on the outside of the CD31-labeled (dotted) endothelial lumen. (J and K) A single transplanted CD44^hi cell (3D image) shown en face (J) and in profile (K) demonstrating the highly ramified morphology taken on by these cells after injection into the eye. Magnification, ×10 (A), ×60 (B–I), ×120 (J and K).