Fig. 1

Mitochondria morphology of mutant TARDBP and C9ORF72 fibroblasts after 48 h in galactose medium. a Representative confocal images of mitochondrial network in fibroblasts from 4 controls (CTRL), 3 ALS patients with the TARDBP p.A382T mutation (mTDP-43) and 4 ALS/FTD patients with mutations in C9ORF72 (mC9ORF72). Fibroblasts were transfected with pDsRed2Mito. Bar, 10 μm. b Quantitative analysis of mitochondrial network in mTDP-43, mC9ORF72 and CTRL fibroblasts labelled with Mitotracker Red dye. Cell distribution in the three arbitrary chosen Shape Factor classes (0–0.3; 0.3–0.6; 0.6–1) was evaluated for each fibroblast group (mean ± SEM; Chi-square test; ***p < 0.001). c Quantitative analysis of mitochondrial network by Aspect Ratio (AR), an indicator of mitochondria length, and Form Factor (FF), reflecting both length and degree of mitochondria branching, in mTDP-43, mC9ORF72 and control fibroblasts transfected with pDsRed2Mito construct. Data are presented in dot plot graphs in logarithmic scale and median values are presented (red bar); Kruskal-Wallis with Dunns post hoc test; ***p < 0.001. d Representative images of electron microscopy analysis of CTRL (panel 1), mTDP-43 (panels 2-3) and mC9ORF72 (panel 4) fibroblasts. Paucity of cristae is indicated by an asterisk. A higher magnification of an unrelated mTDP-43 cell shows two degenerating mitochondria with lamellar distribution of cristae (panel 3, arrowhead). In mC9ORF72 fibroblasts a few autophagic vacuoles (panel 4, pound key) degenerating mitochondria showing mitophagic alterations (arrow) and both lamellar distribution and paucity of cristae (arrowhead) are present. Bar: 0.42 μm (panels 1,2,4); 0,1 μm (panel 3). e Representative WB analysis of MFN1 and FIS1 proteins in CTRL and mTDP-43 fibroblasts (upper panel). Densitometric analyses of WB data are shown (mean ± SEM of 4 controls and 3 TARDBP p.A382T patients, unpaired t-test, **p < 0.01) (lower panel). Lysates from 3 different DIV were considered for each cell line. f Representative WB (upper panel) and densitometric analyses (lower panel) of CTRL and mC9ORF72 fibroblasts (mean ± SEM; n = 3 different DIV; unpaired t-test, **p < 0.01)