Mn induced Aβ plaque formation and increased Aβ mRNA levels, as well as Aβ protein levels, by increasing β-secretase (BACE) and γ-secretase cleavage activities in the cerebral cortex and hippocampus of an AD mouse model, particularly in the microglia [178], suggesting that Mn-induced microglial inflammation likely contributes to amyloidogenesis and AD pathology. Here, BACE1 is linked to Alzheimer disease.