4931414P19Rik: A microglia chemoattractant secreted by neural progenitors modulates neuronal migration during corticogenesis.

Communication between the nervous and immune system is critical for development, homeostasis and response to injury. Prior to the onset of neurogenesis, microglia populate the central nervous system serving as resident immune cells over the course of life. Here, we describe new roles of an uncharacterized transcript upregulated by neurogenic progenitors during mouse corticogenesis: 4931414P19Rik (hereafter named P19). Overexpression of P19 cell-extrinsically inhibited neuronal migration and acted as chemoattractant of microglial cells. Interestingly, effects on neuronal migration were found to result as a direct consequence of P19 secretion by neural progenitors triggering microglia accumulation within the P19 targeted area. Our findings highlight the critical role of microglia during brain development and identify P19 as a novel player in the neuro-immune crosstalk.