SPP1 and Alzheimer disease: Subclusters 0, 1 and 5 were more abundant in CTR than in AD samples and contained homeostatic microglia, as these cells were enriched for homeostasis markers, such as P2RY12 and CX3CR1. Subclusters 7, 9 and 10 were enriched for expression of genes detected in phagocytic/activated microglia derived from amyloid mouse models, including ITGAX, LPL, GPNMB, MYO1E and SPP1 [18, 19].