Migration of microglia in the embryonic neocortex

Abstract

Microglia, the brain macrophages, are suggested to implement key functions during development. In order to do so, they migrate extensively from their entry points to their final locations. However, the mechanisms for microglial migration during mammalian brain development are unknown. Therefore, the goals of this project were to elucidate the migratory behavior of microglia and to determine the presence of adhesion molecules, which could allow interaction with radial cells during murine cortical development. Based on immunohistochemical stainings and live imaging of acute brain slices (of CX3CR1 +/eGFP mice embryos), we suggest that microglia do not migrate according to a specific pattern in the developing neocortex. However, they show that during migration, microglia can adhere to radial cells through molecular interaction with laminin and fibronectin. Instead of following the entire course of the radial cells, microglia could make successive jumps between pillars of radial fibers.