Table 3 Known pathways that contribute to cell and synapse engulfment
Pathways | Findings | References |
|---|---|---|
C1q/C3 | Mice deficient in complement protein C1q or the downstream complement protein C3 exhibit defects in CNS synapse elimination. | Stevens et al. 2007 [63] |
C3/CR3 | Microglia engulf presynaptic inputs during peak retinogeniculate pruning through complement receptor 3(CR3)/C3. Microglia also regulate retinal ganglion cell elimination by CR3-mediated engulfment of nonapoptotic neurons. | Schafer et al. 2012 [1] Anderson et al. 2019 [57] |
Syt11 | Syt11-knockdown increased cytokine secretion and nitric oxide release in primary microglia and enhanced microglial phagocytosis. | Du et al. 2017 [125] |
GPR34 | GPR34-deficient microglia showed reduced phagocytosis activity in both retina and acutely isolated cortical slices. | Preissler et al. 2015 [126] |
MerTK | Activated microglia release Gal-3 and a neuraminidase that desialylates microglial surfaces, enabling their phagocytosis via MerTK. | Grommes et al. 2008 [127] Caberoy et al. 2012 [128] Nomura et al. 2017 [129] |
Syk | Knock down of endogenous Syk decreased microglia phagocytosis of apoptotic neurons. | Scheib. et al. 2012 [130] |