BACE1 and Alzheimer disease: In the qRT-PCR experiment, we found that the level of bace1 mRNA expression in 5xFAD mice was significantly higher than that in littermate wild-type mice (WT+NS vs. AD+NS, 0.86 ± 0.07 vs. 2.77 ± 0.75, p < 0.0001; Figure 3C).