Figure 8. Microglia are eliminated with CSF1R inhibition and not dedifferentiated.

A) Repopulating microglia express CSF1R – 3-day recovery timepoint shown. B) Schematic of the experimental design: 2 month-old mice were treated for 21 days with PLX3397 to deplete microglia (“on”). PLX3397 was then removed from the diet in a second group and repopulation allowed for 14 days (“on-off”). A final group was then treated for a second time with PLX3397 (“on-off-on”, n = 4–5 per group) to determine if repopulated microglia were also eliminated with CSF1R inhibition. C) Representative sections from the hippocampal field for IBA1 and NeuN from each of the four groups. D) Quantification of IBA1 cells in matching full brain sections shows that repopulating microglia are also fully dependent upon CSF1R signaling. E) Schematic of the experimental design: 2 month-old wild-type mice were treated with PLX3397 for 7 days to deplete microglia. PLX3397 was removed to allow microglia to repopulate and BrdU was administered daily to tag these new cells. 7 days later, PLX3397 was re-administered to BrdU-tagged microglia containing mice. F–H) Representative stainings from the hippocampal region for BrdU and IBA1 show that repopulating microglia incorporate BrdU (G) and that PLX3397 treatment eliminates both IBA1 cells and BrdU-incorporated cells (H). I) Quantification of (F–H). Same capital letters above conditions indicates no significant differences (p>0.05) via one-way ANOVA. Error bars indicate SEM.