Figure 2.

Microglial depletion and repopulation by different approaches. (a) Microglia can be efficiently depleted by the administration of tamoxifen in CX3CR1^CreER DTA transgenic mouse. TGF‐β signaling is required for the peripheral myeloid cells invading the brain to colonize the functional microglial niche. (b) The nestin⁺ repopulated cells are transiently expressed after microglia depletion by CSF‐1R inhibitor. Newly repopulated microglia origin from resident microglial pool in the CNS rather than nestin⁺ progenitor cells as well as circulating monocytes. (c) Circulating monocytes, which markedly expressed CD45 and CCR2, can replace the adult CNS myeloid niche after microglial depletion in CD11b‐HSVTK transgenic mouse. (d) Resident microglia proliferation mediated by IL‐1R signaling can refill the microglial niche after partial depletion in CX3CR1^CreER iDTR transgenic mouse