Table 1.

Microglial markers identified from rodent models and human studies

Phenotype	Mouse (gene, protein)	Human (gene, protein)	Morphology [142]
Homeostatic, physiological status [13–16, 143]	Tgfbr1, Smad3, C1qa, C1qb, Cst3, Csf1r, Ctsd, Ctss, Cx3cr1, Entpd1 Fcrls, Hexb, Olfml3, P2y12, Tmem119, Tmsb4x, Sparc	TMEM119 P2Y12 CX3CR1 Fclrs, C1qa, Pros1, Mertk, Gas6 Iba1	Ramified with fine processes
Ageing [17, 18]	MHC class II Complement CR3 (CD11b) CD68, CD11c TLR members CD86	FcγRs (CD64, CD32, CD16b) MHC class II (HLA subtypes, HLA-DR) Complement (C1qA, C1qB, C1qC, C1s, C3, C3AR1, C4, C5, C5AR1), C1QBP, CFH, CFHR1, clusterin TLR members (, TLR2, TLR4, TLR5, MYD88) Calprotectin (S10A8, S100A9), CD14 IRAK3, SOCS3 Inflammasome (Casp1, TXNIP, PANX1, PANX2) Chemokines (CCR1, CXCL5, CXCL16) CD68, CD11b	Ramified Less ramified with shorter and thicker processes
Alzheimer’s disease [14–17, 19]	MGnD profile Apoe,Trem2,Tyrobp,Axl,Clec7a, Ccl2,Csf1,Itgax,Lilrb4, Lgal3, Gpnmb, Fabp5, Spp1 DAM profile Apoe,Trem2,Tyrobp,Axl, B2m, Fth1, Lyz2, Ctsb, Ctsd, Ctsl, Cst7,Csf1, Ccl6, Lpl, Cd9,Itgax,Clec7a,Lilrb4, Timp2	FcγRs (CD64, CD32b, CD16b) MHC II (HLA-DR, DP, DQ) Complement (C4, C3AR1, C5AR1) S100A8 CSFR1 Chemokines (CXCL16, CCR2) TLR (TLR2, TLR4, TLR5, TLR7) CD68, CHI3L1, IL4R, MSR-A	Ramified Less ramified with shorter and thicker processes Ameboid shape (round shape with no processes)

Underlined, common genes identified in both mouse microglial profiles

Apoe, Apolipoprotein; Axl, Tyrosine-protein kinase receptor; B2m, beta-2 microglobulin; C1qA, Complement C1q subcomponent A; C1QBP, C1q binding protein; C3AR1, Complement component 3a receptor 1; C5AR1, Complement component 5a receptor 1; Casp1, caspase 1; Clec7, C-type lectin domain family 7; CCR, Chemokine (C-C motif) receptor type; CHI3L1, Chintinase-3 Like-1; CXCL, Chemokine (C-X-C motif) ligand; Cx3cr1, CX3C chemokine receptor 1 (fractalkine receptor); CFH, Complement Factor H; CFHR1, Complement Factor H Related 1; CR3, Complement receptor 3; Cst3, Cystatin; Ctsd, Cathepsin D; Ctsl, Cathepsin L; Ctss, Cathespin S; Csf1r, Colony-stimulating factor 1 receptor; Entpd1, Ectonucleoside triphosphate diphosphohydrolase 1; Fabp5, Fatty acid binding protein 5; FcγR, Fcγ receptor; Fclrs, Fc receptor-like S; Fth1, Ferritin heavy chain 1; GAS6, growth arrest-specific 6; Gpnmb, Glycoprotein Nmb; GPR34, G protein-coupled receptor 34; HLA, Human leucocyte antigen; Hexb, Beta-hexosaminidase subunit beta; Iba1, Ionised calcium-binding adaptor molecule 1; IRAK3, Interleukin 1 receptor associated kinase 3; Itgax, Integrin alpha X; IRAK3, Interleukin-1 receptor associated kinase 3; Lilrb4, Leukocyte Immunoglobulin Like Receptor B4; Lgal3, Galectin-3; Lpl, lipoprotein lipase; Lyz2, Lysozyme 2; MERTK, C-mer proto-oncogene tyrosine kinase; MHC, Major histocompatibility complex; MSR, Macrophage scavenger receptor; MYD88, myeloid differentiation primary response 88; PAX, Pannexin; Olfml3, Olfactomedin Like 3; P2y12, Purinergic receptor P2Y12; Pros1, Protein S; S100A8, S100 calcium-binding protein A8; Smad3, SMAD family member 3; SOCS3, Suppressor of cytokine signalling 3; Sparc, Secreted protein acidic and cysteine rich; Spp1, Secreted phosphoprotein 1; Timp2, Metallopeptidase inhibitor 2; Tgfbr1, Transforming Growth Factor Beta Receptor 1; TLR, Toll-like receptor; TMEM, Transmembrane protein; Tmsb4x, Thymosin Beta 4 X-Linked; Tyrobp, TYRO Protein Tyrosine Kinase Binding Protein; Trem2, triggering receptor expressed on myeloid cells 2; TXNIP, Thioredoxin-interacting protein