Table 1.

Recently identified microglial phenotypic states identified in single cell RNA-seq studies.

Microglial phenotypic state	Acronym	Sex Effect?	Description	Citation
Disease-associated microglia	DAM	N/A	AD risk genes, associate with Aβ plaques	Keren-Shaul et al., 2017 [100]
Microglial neurodegenerative phenotype	MGnD	N/A	Clec7a, Lgals3, Gpnmb, Itgax, Spp1, Ccl2, Fabp5	Kraseman et al., 2017 [320]
Activated Response Microglia	ARM	Female microglia have faster progression to ARM in APPNL-G-F mice	MHCII-high, tissue repair & AD risk genes	Sala Frigerio et al., 2019 [35]
Interferon-Response Microglia	IRM	No sex difference found	Innate immune & interferon type I pathways	Sala Frigerio et al., 2019 [35]
Axon Tract-Associated Microglia	ATM	No sex difference found	Localized to axon tract at restricted developmental window, SPP1, IGF1, lysosomal genes	Hammond et al., 2019 [99]
Proliferative-region-associated microglia	PAM	N/A	DAM markers, metabolically active, phagocytose oligodendrocytes	Li et al., 2019 [103]
Human AD microglia	HAM	Mostly restricted to sex chromosomal genes	Distinct from DAM, upregulate APOE, aging signature	Srinivasan et al., 2020 [27]
Lipid-droplet-accumulating microglia in aging mice and humans	LDAM	N/A	Production of nitric oxide and ROS, lysosomal genes, lipid metabolism	Marschallinger et al., 2020 [101]
White matter-associated microglia	WAM	Did not notice any sex effects, no presented analysis of sex effects	TREM2, APOE, as well as DAM markers	Safaiyan et al., 2021 [104]
Microglia inflamed in multiple sclerosis	MIMS	Sex matching applied, no presented analysis of sex effects	C1q, as well as DAM markers	Absinta et al., 2022 [102]