Fig. 7.

Spheroidal formation of mitochondria in iPSC-derived dopaminergic neurons under CCCP treatment. a SEM images of GFP-positive dopaminergic neurons derived from control and PRKN-mutated TH-GFP iPSC lines under normal conditions. “PRKN” represents PRKN-mutated patient. No spherical mitochondria of total mitochondria (control GFP-nega; n = 745, control GFP-posi; n = 1427, PRKN GFP-nega; n = 811, PRKN GFP-posi; n = 1178) was observed in the SEM images of differentiated cells. Scale bar, 1 µm. b SEM images of GFP-positive dopaminergic neurons derived from control and PRKN-mutated TH-GFP iPSC lines under CCCP treatment for 3.5 h. Mitochondrial structures painted cyan and indicated by arrowheads represent spherical mitochondria. “PRKN” represents PRKN-mutated patient. Scale bar, 1 µm. The inset shows an image of one of the spherical mitochondria without painting. Scale bar of the inset, 500 nm. c Quantitative analysis of the percentage of spherical mitochondria in total mitochondria (control GFP-nega; n = 562, control GFP-posi; n = 850, PRKN GFP-nega; n = 736, PRKN GFP-posi; n = 774) from the SEM images of differentiated cells, as in (a). “PRKN” represents PRKN-mutated patient. Values are shown as the mean ± SEM. Statistical significance was evaluated using the two-way ANOVA with Šidák’s multiple comparisons test. ***P < 0.001. There was no significant difference in the percentage of spherical mitochondria between control and PRKN-mutated GFP-negative cells (P = 0.1038). There was also no significant difference in the percentage of spherical mitochondria between GFP-negative and GFP-positive cells (control; P = 0.8825, PRKN; P = 0.2222)