Fig. 1

YAC128 MSNs co-cultured with cortical neurons at a 1:3 CS ratio recapitulate in vivo spine loss. WT and YAC128 (Y128) co-cultures were generated at either a 1:1 or 1:3 CS ratio and processed at DIV21 for DARPP32 and MAP2 immunocytochemistry, imaging, and spine analysis in NeuronStudio. (a) Sample images of DARPP32- and MAP2-stained dendrites in CS co-culture (scale bar = 5 μm). (b) Quantification of DARPP32 staining intensity normalized to MAP2 intensity reveals no differences between genotypes or conditions [n = 30(3); two-way ANOVA with Bonferroni post-hoc analysis]. (c) Sample images of DARPP32-stained spines on secondary or tertiary dendrites in co-cultured MSNs at higher exposure (scale bar = 5 μm). The differences in numbers of (Di) total and (Dii) mature mushroom, but not (Diii) immature spines, are exacerbated in 1:3 co-cultured YAC128 MSNs [n = 32(4); two-way ANOVA with Bonferroni post-hoc analysis; *p < 0.05, ***p < 0.001]. (e) Representative Golgi staining of striatal MSNs in vivo (scale bar = 5 μm). (f) Golgi analysis confirms that reduced MSN total spine number occurs by 12 months of age in the YAC128 striatum, to a similar degree as in 1:3 co-cultures [n = 4–5 6-month-old animals and 3 12-month-old animals per genotype; two-way ANOVA with Bonferroni post-hoc analysis; **p < 0.01]. Individual data values for graph in F are available in Additional file 1. A linear correlation exists between (Gi) total and (Gii) mushroom spines versus the proportion of striatal cells at plating. A significant interaction occurs between striatal proportion and genotype [n = 30(3); two-way ANOVA with Bonferroni post-hoc analysis; *p < 0.05, **p < 0.01, ***p < 0.001]