Remarkably, several genes (such as Clec7a, P2ry12, Itgax and others), that have been recently associated to Aβ activated microglia in AD mouse models [23, 27], as well as in human AD brains [56, 63], displayed altered expression in microglia from GF 5xFAD mice, indicating a certain microbiota-dependent influence on this microglial activation state. This evidence concerns the gene P2RY12 and Alzheimer disease.