Importantly, reprogramming for 25 days resulted in a significant decrease in the number of Synapsin1+/VGLUT1+ puncta in the AD patient iNs with APOE ε4 expression from day 7, the amyloid-seeding state; in contrast, APOE ε4 expression after the amyloid-seeding state did not affect the number of Synapsin1+/VGLUT1+ puncta (Fig. 1i, j). Here, APOE is linked to Alzheimer disease.