In a recent study, Aulston et al. demonstrated that treatment with EVs (presumably mostly exosomes), isolated from induced pluripotent stem-cell (iPSc)-derived neuronal cultures generated from a patient harboring the familial-AD-associated A246E of presenilin-1, which increases the Aβ42/Aβ40 ratio, induced tau phosphorylation in wild type C57BL/6 mouse brain (Aulston et al., 2019). Here, MAPT is linked to Alzheimer disease.