Zhang et al. proved that when chronic cerebral hypoperfusion (considered to be a high risk factor for AD) occurred, amyloid β-peptide could inhibit miR-124 and promote the beta-site amyloid precursor protein cleaving enzyme 1(BACE1) expression, which was identified as a rate-limiting enzyme for amyloidβ-peptide synthesis. Here, BACE1 is linked to Alzheimer disease.