Figure 1.

Effects of microglia‐derived factors on oligodendrocyte lineage depending on microglial subsets. A pro‐inflammatory microglial subset secretes cytokines and reactive oxygen species (ROS) that can directly damage oligodendrocytes thus resulting in demyelination. Immuno‐regulatory subsets secrete trophic factors that promote OPC migration and differentiation thus resulting in remyelination. Switching the pro‐inflammatory subset into an immuno‐regulatory subset may represent a potential therapeutic approach for rescuing white matter in CNS injury and disease. Note that microglia‐derived TNFα and IL‐1β can both be cytotoxic or beneficial to oligodendrocyte lineage cells (marked in red). These complex effects are likely to be dependent on signals from neighboring cells and surrounding environmental conditions. Future studies are warranted to investigate how and why identical factors from microglia can show opposite effects on oligodendrocyte damage/recovery