MAPT and Alzheimer disease: In APP/PS1 mice, upregulation of TREM2 can inhibit GSK-3β, the major kinase involved in Tau hyperphosphorylation in AD, by activating the PI3K/Akt signaling pathway, thereby inhibiting the phosphorylation of Tau protein, and has similar effects in SH-SY5Y cells (Peng et al., 2023).