BACE1 and Alzheimer disease: In particular, the synapse-enriched miR-9 [40] regulates different AD-related genes (BACE1, CREB, OPTN, and CAMKK2) influencing Aβ production and autophagy [34,38,39,40], together with other targets related to neurotrophic proteins [41,273] (Table 1, Figure 2).