Figure 3.

Murine brain organoids switch from glycolysis to oxidative phosphorylation during development

(A) Mitochondrial DNA (mtDNA) in organoids progressively increases over time, suggesting an increment of mitochondrial mass from day 7 to day 32. n = 9 organoids for each time point. Data are reported as mean ± SEM. Statistical differences in graphs were calculated by ordinary one-way ANOVA. P < 0.05 was considered statistically significant. ∗∗∗p < 0.001; ∗∗p < 0.01; ∗p < 0.05.

(B) Representative western blotting analysis of organoids at different time points shows an increase in OXPHOS complex subunits (ATP5A, UQCRC2, MTCO1, SDHB, NDUFB8), and VDAC1 when reported to nuclear marker Lamin B, suggesting an intensification of electron transport chain activity and acquired mitochondrial mass in the cells composing mature organoids.

(C–H) Quantitative analysis of the western blotting described in (B). n>3 organoids for each time point. Data are expressed as mean ± SEM. Statistical differences in graphs were calculated by ordinary one-way ANOVA. P < 0.05 was considered statistically significant. ∗∗∗∗p < 0.0001; ∗∗∗p < 0.001; ∗∗p < 0.01.

(I) Graphs showing the total ATP content (expressed as A.U. relative to glucose) measured in organoids fed with different carbon sources (glucose – GLC; galactose – GAL) at different time points (n = ≥8 samples/time point), and normalized to cell number. Data are expressed as mean ± SEM. Statistical differences were evaluated by a two-tailed unpaired ttest for two datasets (glucose vs galactose) at each time point. P < 0.05 were considered significantly different. ∗∗∗p < 0.001; ∗∗p <0.01; ∗p <0.05.