H2AX and amyotrophic lateral sclerosis: Representative images showing the difference in the number of γ-H2AX-labeled DSB foci in the nuclei of ALS-hMSCs and HC-hMSCs before and 1 h after NCS treatment are shown in Fig. 1D. Differences in the number of γ-H2AX foci are quantified in Fig. 1E. In both ALS-hMSCs and HC-hMSCs, pATM and pDNA-PK protein expression levels significantly increase 1 h post NCS induction, decreasing back to almost the basal level at 2 to 4 h post NCS induction, as expected (Fig. 1B,C, respectively).