MAPT and Alzheimer disease: Increased expression of miR-15a can inhibit extracellular signal-regulated kinase (ERK) 1/2 and tau protein phosphorylation, thereby improving cognitive dysfunction in mice, alleviating pathological damage in the hippocampus of AD mice, and inhibiting hippocampal neuronal apoptosis (Li X. et al., 2020; Yang et al., 2020) (Shown in Figure 1 and Table 1).