Fig. 5: Npdc1 deficiency limits nigral cell loss and improves motor function after striatal α-syn PFF injection.

a Diagram illustrating the experimental design for α-syn PFF injection into wt and Npdc1−/− mice striatum. Created in BioRender. Chen, M. (2025) https://BioRender.com/9w6mss6. b Representative images showing TH and p-α-syn co-staining in the caudate-putamen of wt and Npdc1−/−mice injected with α-syn PFF. Scale bar, 100 µm. c Graph shows mean ± SEM of striatal TH levels in the ipsilateral side of the striatum in wt and Npdc1−/− mice injected with α-syn PFF. N = mouse number is shown above each bar. One-way ANOVA with Tukey’s post hoc test. p = 0.15 for WT + PBS vs WT + PFF. d Graph shows mean ± SEM of striatal p-α-syn levels in the ipsilateral side of the striatum in wt and Npdc1−/− mice injected with α-syn PFF. N = mouse number is shown above each bar. One-way ANOVA with Tukey’s post hoc test. ***p < 0.0001 for WT + PBS vs WT + PFF; *p = 0.020 for Npdc1−/−+PBS vs Npdc1−/−+PPF; p = 0.075 for WT + PFF vs Npdc1−/−+PFF. e Representative images of TH staining in ipsilateral side of the SNc of wt and Npdc1−/− mice injected with α-syn PFF. Coronal section with dorsal up and midline to left. Scale bar, 500 µm. f Graph shows mean ± SEM of TH positive neurons in the ipsilateral side of the SNc of wt and Npdc1−/− mice injected with α-syn PFF. N = mouse number is shown above each bar. One-way ANOVA with Tukey’s post hoc test. ***p < 0.0001 for WT + PBS vs WT + PFF; **p = 0.0014 for WT + PFF vs Npdc1−/−+PPF. g Graph shows the percentage of wt and Npdc1−/− mice injected with α-syn PFF remaining in the inverted grid in the wire screen test. N = mouse number is shown next to the group label. Gehan–Breslow–Wilcoxon test. p = 0.75 for Npdc1−/−+PBS vs Npdc1−/−+PFF; p = 0.054 for WT + PFF vs Npdc1−/−+PFF.