APOE and Alzheimer disease: Of note, although increased ApoE levels were detected by recent (single-cell and single-nuclear) RNAseq studies in microglia from human AD postmortem brain tissue, a subpopulation with DAM signature was not identified (Grubman et al., 2019; Olah et al., 2020; Srinivasan et al., 2020; Zhou et al., 2020).