To achieve full maturation of microglia, we subjected the PMPs to a carefully designed 7-day treatment regimen. This involved the addition of interleukin-34 (IL-34) (100 ng/ml; PeproTech, catalog #200-34) and granulocyte-macrophage colony stimulating factor (GM-CSF) (10 ng/ml; PeproTech, catalog #300-03) to Dulbecco’s modified Eagle’s medium (DMEM)/F12 (HyClone, catalog #SH30023.01) containing N-2 supplement (Gibco, catalog #17502048). This protocol facilitated the maturation process of the PMPs into microglia.