Since the increase in the relative ratio of Aβ42 to Aβ40 (Aβ42/Aβ40) is a common result of familial AD-associated PSEN1 mutations (Sun et al., 2017) and plays an important role in AD pathogenesis (Kwak et al., 2020), we determined the effect of miR-3940-5p on the ratio of Aβ42/Aβ40. The data showed that there is no significant difference in the ratio of Aβ42/Aβ40 cross the miR-3940-5p mimics group, PSEN1-siRNA group, and the control group (Figure 4D). The gene discussed is PSEN1; the disease is Alzheimer disease.