Purines induce directed migration and rapid homing of microglia to injured pyramidal neurons in developing hippocampus

Abstract

Traumatic CNS injury activates and mobilizes resident parenchymal microglia (MG), which rapidly accumulate near injured neurons where they transform into phagocytes. The mechanisms underlying this rapid ‘homing’ in situ are unknown. Using time-lapse confocal imaging in acutely excised neonatal hippocampal slices, we show that rapid accumulation of MG near somata of injured pyramidal neurons in the stratum pyramidale (SP) results from directed migration from tissue regions immediately adjacent to (in situ. Rapid, ATP/ADP-dependent MG homing may promote clearance of dead and dying cells and help limit secondary damage during the critical first few hours after neuronal injury.