Article Figures & Data
Figures
- Figure 1.
3D reconstruction of dendrites and spines from WT and A53T-BAC-SNCA mice at different ages. A, Membrane contours of dendrites (d), spines (s), and presynaptic terminals (t) can be clearly observed in the FIB/SEM image from a 1-month-old WT mouse. Mitochondria and other organelles are also clearly visible. Scale bar: 500 nm. B–I, 3D reconstruction of dendrites (orange) and spines (violet) from WT mice at 1 (B), 3 (C), 6 (D), and 22 (E) months of age and from A53T-BAC-SNCA mice at 1 (F), 3 (G), 6 (H), and 22 (I) months of age. Red regions in the spine heads indicate postsynaptic densities. Scale cubes: 0.5 µm on each side.
- Figure 2.
Morphologic alterations in spines in WT and A53T-BAC-SNCA mice with age. A, Age-related changes in spine density. The graph shows that spine density decreased with age in both the WT and A53T-BAC-SNCA mice. In WT mice, the spine density at 1 and 3 months was significantly lower compared with that at 6 and 22 months (**p = 0.003 between 1 and 6 months, ***p < 0.001 between 1 and 22 months, *p = 0.03 between 3 and 6 months, **p = 0.001 between 3 and 22 months; one-way ANOVA). In A53T-BAC-SNCA mice, there were fewer spines at 22 months compared with that at 1 and 3 months (*p = 0.01 between 1 and 22 months, *p = 0.01 between 3 and 22 months; Kruskal–Wallis test). B, Age-related changes in spine head volume. The average spine head volume increases with age in the WT (red open circle), but not A53T-BAC-SNCA (black open circle), mice. In WT mice, spine head volume at 1 month was significantly smaller than that at 3, 6, and 22 months (***p < 0.001 between 1 and 3 months, ***p < 0.001 between 1 and 6 months, ***p < 0.001 between 1 and 22 months; Kruskal–Wallis test). Median head volume is shown by the + symbol. C, Age-related changes in spine neck length. The spine neck length did not vary significantly with age in either WT or A53T-BAC-SNCA mice. Different levels of significance are denoted by the number of asterisks (*p <0.05, **p <0.01, ***p <0.001).
- Figure 3.
The frequency of large spines increased with age in WT, but not A53T-BAC-SNCA, mice. A, The distribution of large spines in WT mice was significantly different between 6 and 22 months of age (*p = 0.01, Kolmogorov–Smirnov test). B, In contrast, the distribution of large spines was not significantly different between 6 and 22 months of age in A53T-BAC-SNCA mice (p = 0.86, Kolmogorov–Smirnov test).
- Figure 4.
Examples of perforated spines in WT mice at 22 months of age. A–D, Serial images of a large spine (s). Arrows in B, C show the discontinuity of the PSD. Scale bars: 500 nm. E–G, Representative images of a 3D reconstruction of spines showing a doughnut-shaped perforated PSD with a hole at the center. Spine heads, spine necks, and PSDs are shown in violet, blue, and red, respectively. Scale cubes: 0.25 µm on each side.
- Figure 5.
PSD area was correlated with spine head volume in both WT and A53T-BAC-SNCA mice. A–H, A significant, positive linear correlation exists between PSDs and spine head volumes in both WT (A, C, E, G) and A53T-BAC-SNCA (B, D, F, H) mice at all four examined ages [1 month (A, B); 3 months (C, D); 6 months (E, F); 22 months (G, H)]. The correlation coefficients and the p values for the test of statistical significance of correlation are denoted by r and p, respectively, in the corresponding graphs. Correlation was examined using Spearman’s rank order test.
- Figure 6.
Localization of phosphorylated α-synuclein in a subset of presynaptic terminals in A53T-BAC-SNCA mice. A–D, TEM images of pre-embedding immunogold-labeled samples from A53T-BAC-SNCA mice at 1 (A), 3 (B), 6 (C), and 22 (D) months. Note that the immunogold particles, indicating phosphorylated α-synuclein, were predominantly localized to presynaptic terminals. Immunogold particles were often seen in clusters. E, A low-magnification image from an A53T-BAC-SNCA mouse at 3 months of age demonstrates that a subset of large presynaptic terminals was immunopositive for phosphorylated α-synuclein. s: spine; T: presynaptic terminals with immunoreactivity for phosphorylated α-synuclein; t: presynaptic terminals lacking immunoreactivity for phosphorylated α-synuclein. Scale bars: 500 nm.
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