Fig. 6
Mapping of 13C isotope labeling in three abundant organelles following α-syn overexpression. a Representative SEM images of large neuronal cell bodies comparing the SNpc injected with the control non-coding vector (left panel) and the AAV6-α-syn vector (right panel). Note the changes in organelle morphology caused by α-syn overexpression, with fragmented ER and Golgi apparatus and round-shaped mitochondria with abnormal cristae. Cy: cytoplasm; Nu: nucleus; n: nucleolus; m: mitochondria; g: Golgi apparatus. b Maps of 13C isotope enrichment in the corresponding regions of the neuronal cell bodies. Note the regions analyzed at high resolution to determine 13C levels in specific organelles. The lower panels show high-magnification images corresponding to the regions indicated by dashed rectangles. Note the low 13C enrichment in the mitochondria in the pathologic condition. c Measurement of the length-to-width ratio of mitochondria in the neuronal cell bodies, comparing the control and α-syn-overexpressing hemispheres. The thick lines in the violin plots represent the median and the thin lines the upper and lower quartiles. The numbers of mitochondria analyzed from 2 rats per condition are indicated in the x-axis labels. d Relative number of mitochondria-ER contacts (MERC) normalized to the total length of mitochondria perimeter (N = 6 neurons from 2 rats per condition). Data represent mean ± standard error (SE). Statistical analysis: Mann–Whitney unpaired two-tailed test; ns = not significant; **P < 0.01; ****P < 0.0001