Review Article

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

Figure 1

Chemotaxis or phagocytosis-involved receptors in microglia and correlation of the inflammatory or anti-inflammatory response. Many of the receptors correlated with microglial activities of chemotaxis (migration) or phagocytosis, respectively. Among these, some of the receptors possess not merely single function; CCR1 is the migration-inducing receptor that also possesses phagocytotic activity. CCR2 and CCR5 are also the migration-inducting receptors that lead to anti-inflammatory response. CX3CR1 contributes to migration, phagocytosis, and anti-inflammatory response. TREM2 and MFG-E8 induce phagocytosis and anti-inflammatory response. CD47 and CD200R usually induce phagocytosis under pathological condition, so that they indirectly contribute to anti-inflammatory status. TLR9 activates microglia to induce phagocytosis with producing proinflammatory and anti-inflammatory molecules. There are receptors inducing not only phagocytosis but also inflammatory response (CD14, CD36, RAGE, TLR1, TLR2, TLR4, and TLR6). Within these receptors that the synergistic signaling involved Aβ-triggering inflammatory response are CD14-TLR2-TLR4 and CD36-TLR2-TLR6.
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