Abstract

Neuronal regeneration to replenish lost neurons after injury is critical for brain repair. Microglia, brain‐resident macrophages that have the propensity to accumulate at the site of injury, can be a potential source for replenishing lost neurons through fate conversion into neurons, induced by forced expression of neuronal lineage‐specific transcription factors. However, it has not been strictly demonstrated that microglia, rather than central nervous system‐associated macrophages, such as meningeal macrophages, convert into neurons. Here, we show that NeuroD1‐transduced microglia can be successfully converted into neurons in vitro using lineage‐mapping strategies. We also found that a chemical cocktail treatment further promoted NeuroD1‐induced microglia‐to‐neuron conversion. NeuroD1 with loss‐of‐function mutation, on the other hand, failed to induce the neuronal conversion. Our results indicate that microglia are indeed reprogrammed into neurons by NeuroD1 with neurogenic transcriptional activity.