Fig. 2

MATR3 levels and sub-cellular localization are perturbed in C9-ALS patient neurons and in post-mortem brain tissue. a Representative confocal images of control and C9-ALS patient-derived iPSCs that were differentiated to neurons (represented by ChAT⁺, green) and stained for endogenous MATR3 (red/gray). b Quantification of endogenous MATR3 immunofluorescence levels in ChAT⁺ neurons revealed significantly lower MATR3 levels in C9-ALS iPSC-MNs compared to that in control iPSC-MNs (Unpaired t-test) n = 2-3 independent differentiations from each independent control and C9-ALS iPSC-derived MN. iPSC-MNs from control: Ctrl #1 (yellow circle), Ctrl #2 (green circle), Ctrl #3 (cyan circle). iPSC-MNs from C9-ALS: C9-ALS #1 (gray circle), C9-ALS #2 (blue circle), C9-ALS #3 (purple circle). c Quantification of MATR3 mRNA fold change in control and C9-ALS iPSC MNs showed significantly reduced MATR3 mRNA levels in C9-ALS iPSC-MNs compared to that in control (Mann–Whitney U-test). n = 3 independent differentiations from each independent control and C9-ALS iPSC-derived MN. iPSC-MNs from control: Ctrl #1 (yellow circle), Ctrl #2 (green circle). iPSC-MNs from C9-ALS: C9-ALS #1 (gray circle), C9-ALS #3 (purple circle). d Representative IHC staining for MATR3 in entorhinal cortex sections from control, C9-ALS and sporadic (non-C9) ALS patient post-mortem brains. MATR3 was predominantly nuclear in control and sporadic ALS tissues, whereas in C9-ALS patient tissue, MATR3 also showed intense cytoplasmic signal (blue arrows). Scale = 50 µm. e Quantification of percentage of neurons with cytoplasmic MATR3 revealed increased percentage of neurons with cytoplasmic MATR3 staining in C9-ALS compared to control (Unpaired t-test). Control: 3 cases (n = 330; 135; 93); C9-ALS: 6 cases (n = 93; 485; 217; 310; 500; 251) and non-C9 sporadic-ALS: 3 cases (n = 316; 197; 402). Error bars indicate S.E.M. *p value < 0.05; ***p value < 0.001; ****p value < 0.0001