Fig. 1. Live imaging of astrocytes and microglia during cell corpse removal.

(A) Photochemical ablation and induction of single-cell apoptosis via 2Phatal in live mouse cortex. (B) Hoechst 33342 dye labeling of cell nuclei (blue), fluorescently labeled neurons (white), and microglia (green) before 2Phatal. The boxed region is magnified, and time-lapse imaging shows targeting of a single neuron for 2Phatal (blue arrow) followed by a single microglial cell occupying the territory of the ablated neuron 24 hours later. (C) Time-lapse imaging showing microglia engulfment of a dying neuron with a condensed nucleus (red arrow). (D) Traces depicting 21 cell death events, showing the timing of microglia arrival and engagement with the dying cells from four mice. (E) Time-lapse imaging detailing microglia engulfment of apoptotic neurites (red arrows) over 6 hours. (F) Time-lapse imaging showing subtle astrocyte polarization around a cell targeted with 2Phatal (green arrowheads). (G) Timing of astrocyte engagement with 15 single dying cells collected from four mice. (H) Time-lapse imaging showing the dynamic formation of astrocyte polarization around apoptotic neurites over 6 hours (green arrowheads).