Figure 7.

iMG cells respond to and migrate toward an injured neuron cluster

(A) Experimental design of the laser-induced neuronal injury.

(B) Cell death of N2-iNs was monitored using propidium iodide (PI) staining. Each selected iN cluster was exposed to 405-nm laser light for 5 min and immediately examined by time-lapse imaging (sampling rate of 1/300 Hz) for PI signal. Scale bar, 20 μm.

(C) An example of the time-lapse DIC imaging of co-cultures with or without laser-induced neuronal injury (recorded for 12 h). Blue arrows in the DIC images mark an iMG cell migrating toward the central iN cluster. The two-panel images on the right show the results of cell traces, which are presented as a color-coded trajectory for each cell over 12 h. The displacement of each cell is shown on the right. Scale bar, 100 μm.

(D) Measurements of the distance between each iMG cell and the central iN cluster in the control and laser ablation groups for each time point. Different cells are coded by color and are from a representative experiment.

(E) The graph depicts the results of relative distance changes over time for the four conditions. Data are means ± SEM (n = 46 N2-iMG cells in 5 fields [no laser control]; n = 58 N2-iMG cells in 6 fields [laser ablation]; n = 41 N2-iMG cells in 8 fields [no laser control and PSB application]; n = 33 N2-iMG cells in 8 fields [laser ablation and PSB application]).

(F) The percentage of iMG cells that are able to contact the central iN cluster over the 12-h recording period. Data are means ± SEM (n = 5–8 fields). ^∗p < 0.05 by one-way ANOVA with Fisher's LSD multiple comparisons.