P2RY12 and Alzheimer disease: A reduced expression of P2RY12, a marker traditionally linked to homeostatic microglia and downregulated in mouse disease-associated microglial signatures [DAM (Keren-Shaul et al., 2017), MGnD (Krasemann et al., 2017)], and dark microglia (Bisht et al., 2016b) was observed in frontal and temporal cortices of human post-mortem AD brains compared to control individuals (Maeda et al., 2021).