Sweepers in the CNS: Microglial Migration and Phagocytosis in the Alzheimer Disease Pathogenesis

Table 1

Various chemotaxis or phagocytosis-related receptors in microglia and its ligand(s) or interacted factors. Microglia are activated with various stimuli through the specific receptor of each stimuli. For detailed review of chemokines, pathogens, and factors associated with tissue damage recognized by microglia, refer to [19–21].

Receptor type	Subtypes	Ligand(s)/interacted factors
	CCR1	CCL3 (MIP-1α), CCL5 (RANTES), CCL7 (MCP-3),; CCL9 (MIP-1γ), CCL14 (HCC-1), CCL15 (HCC-2/leukotactin-1),; CCL16 (HCC-4/LEC), CCL23 (MPIF-1)
Chemokine receptor	CCR2	CCL2 (MCP-1), CCL7 (MCP-3), CCL8 (MCP-2), CCL13 (MCP-4), CCL16 (HCC-4/LEC)
	CCR5	CCL3 (MIP-1α), CCL4 (MIP-1β), CCL5 (RANTES)
	CXCR3	CXCL9 (Mig), CXCL10 (IP-10), CXCL11 (I-TAC)
	CX3CR1	CX3CL1 (Fractalkine)
Purinergic receptor	P2X4, P2Y7, P2Y12; P2Y6	ATP, ADP; UDP
TLR	TLR1; TLR2; TLR4; TLR6; TLR9	Triacyl lipopeptides; Glycolipids, Hsp70, HMGB1, Aβ; LPS, Hsp; Diacyl lipopeptides; CpG-DNA
Phosphatidylserine (PS) receptor	MFG-E8, Tim1, Tim4; RAGE	PS of apoptotic cells; Aβ, AGE, HMGB1 PS of apoptotic cells
Scavenger receptor (SR)	SR-AI/II (CD204), SR-BI, CD36	Cellular debris, apoptotic cells, Aβ (CD36)
Immunoglobulin (Ig) receptor	FcγRI, FcγRIII	Ig-opsonized particles
Complement receptor (CR)	CR3 (MAC-1; CD11b/CD18)	Complement components, opsonized particles
Other phagocytosis-related receptor	CD14; CD47; CD200R; TREM2	LPS, Aβ; SIRPα (CD172a); CD200; Hsp60, DAP12