[2P-052] Extracellular micronuclei from neurons regulate the microglial activity during brain development
Awardees for Travel Award
Microglia mediate the removal of neural debris during brain development. The mechanism by which microglia recognize and remove the damaged neurons during development has not been fully elucidated. Here, we propose that the micronuclei are secreted from neurons during the developmental stages, followed by regulating microglia activity. Micronuclei are cytosolic chromatin structures that are compartmentalized by a nuclear envelope. Micronuclei emerge in migrating neurons and are cleared by the autophagic pathway. We show that micronuclei are secreted to the extracellular region from neurons in vitro by using NexCre;Sun1-sfGFP-myc mice, which are the neuron-specific nuclear membrane labeling mouse. In addition, we observed that extracellular micronuclei released from neurons were taken into microglia in vivo. Microglia with micronuclei strongly expressed CD68, which is a phagocytosis marker. Furthermore, we found that CD68 localized in micronucleus in microglia, suggesting that micronuclei are degraded via endosome-lysosomal pathway within microglia. These microglia exhibit amoeboid shape and have thicker primary branches with larger cell bodies which are known as active microglial morphology. Taken together, our data provide the possibility that micronuclei act as a novel factor that controls microglial activation during brain development.