(A) CatB activities in hippocampal lysates from CST3+/+, CST3+/− or CST3−/− mice (n= 6, ***, P < 0.001, one-way ANOVA with Tukey-Kramer post hoc test).
(B) ELISA measurements of Aβ1–42 or Aβ1-x in the supernatants of primary cortical cultures (CST3+/+ or CST3−/−) infected with hAPPV642I adenovirus. All measurements were normalized to protein concentrations in the cell lysates (n= 4, **, P < 0.01, Mann-Whitney U test. Average Aβ levels in CST3+/+ cultures were arbitrarily set as 1).
(C–E) ELISA measurements of hippocampal levels of soluble Aβ1-x and Aβ1–42 in 2–4-month-old hAPP-J20 mice. Deleting one or both alleles of CST3 significantly reduced levels of soluble Aβ1-x (C) and Aβ1–42 (D). Ablating CysC also reduced Aβ1–42/Aβ1-x ratios significantly (E). (n = 9–21 mice/genotype, ***, P < 0.001; **, P < 0.01, *, P < 0.05, one-way ANOVA with Tukey-Kramer post hoc test). Bars = means ± SEM (A–E).