(A and B) Vps26b mice were tested in the novel object recognition (NOR) and object-context recognition (OCR) tasks at 3 time points, as described in STAR Methods. Data are expressed as mean ± SEM. A two-way ANOVA with Bonferroni’s post hoc test was used for the analysis.
(A) In the NOR task targeting the perirhinal cortex (n = 10 animals for each of the 6 independent groups), a defect in memory performance was observed only in 12- to 14-month-old mice.
(B) In the entorhinal-sensitive OCR task (n = 10–14 for each of the 6 independent groups), a two-way ANOVA with Bonferroni’s post hoc corrections revealed a significant genotype X age interaction that was driven by age-related worsening in the Vps26b KO mice: F(2,67) = 13.92, p < 0.001.
(C) OCR defects were also found in 12- to 14-month-old Vps26b HET mice versus their WT littermates (n = 9–14 per independent group; p = 0.0016, in unpaired non-parametric Mann-Whitney t test) but not in 12- to 14-month-old Vps26a HET mice versus their WT littermates (n = 8 per group; p = 0.5077, in unpaired two-sided Student’s t test).
(D) Schematic representation of the mouse brain showing the injection site in the lateral recess of the lateral ventricle (image 77, http://atlas.brain-map.org/atlas?atlas=602630314#atlas=602630314&structure=549&resolution=10.26&x=5700&y=4000&zoom=-3&plate=576989860) (left panel). VPS26b overexpression in the EC of WT mice (C57BL6/J): mice were injected at 3 months of age with AAV9-VPS26b at different doses and volume and harvested at 4 months of age (top right panel). VPS26b rescue in EC of Vps26b KO mice: mice were injected at ~3.7 months of age, and brains were harvested at ~7.7 months (bottom right panel).
(E) Vps26b mice were tested in the OCR task. Data are expressed as mean ± SEM. As expected, a defect in memory performance was observed in the Vps26b KO mice compared with the Vps26b WT controls, both injected with AAV9-GFP (n = 4–6 per group, p = 0.0028, in unpaired two-sided Student’s t test). An OCR behavioral rescue was observed in Vps26b KO mice injected with AAV9-VPS26b compared with Vps26b KO mice injected with AAV9-GFP alone (n = 4–6 animals/group, p = 0.0044, in a one-way ANOVA with Tukey’s post hoc test [two-sided]). *p < 0.05, **p < 0.01, and ***p < 0.001.
(F) Mean fEPSP slopes expressed as a percentage of baseline measured before and after high-frequency stimulation in the TEC region of Vps26b WT– AAV9-GFP (n = 5), Vps26b KO – AAV9-GFP (n = 6), and Vps26b KO – AAV9-VPS26b (n = 6) mice. In a two-way repeated measured ANOVA test with a Dunnett’s post hoc, a rescue of LTP defects is observed in Vps26b KO mice injected with AAV9-VPS26b-GFP compared with Vps26b KO mice injected with AAV9-GFP (Vps26b KO – AAV9-VPS26b-GFP: 151.6% ± 0.40% versus Vps26b KO – AAV9-GFP: 103.6% ± 0.95% versus Vps26b WT – AAV9-GFP: 178.3% ± 1.08%, F[2,14] = 6.427, p = 0.0105).
See also Figure S7.