Figure 9. Schematic representation of the mechanism of BMT-mediated neuroprotection in neurodegeneration of inner retina.

Endogenous microglia (right side) have a pro-inflammatory phenotype that results in impaired phagocytosis of Aβ and increased elaboration of ROS, resulting in increased neurotoxicity. In contrast, BM-derived peripheral blood monocytes migrate into the retina through the blood retinal barrier, and then differentiate into microglia characterized by MHC class II expression. This altered molecular phenotype mediates increased clearance of Aβ and reduced elaboration of neurotoxic ROS.