MAPT and Alzheimer disease: Currently, the Aβ cascade hypothesis continues to dominate AD research, with abundant evidence supporting that Aβ overproduction alters cellular metabolism, triggers downstream events including tau hyperphosphorylation, neurodegeneration, neuroinflammation, and synaptic dysfunction, and further causes progressive memory loss and cognitive dysfunction (Billings, Oddo, Green, McGaugh, & LaFerla, 2005; Hardy & Selkoe, 2002).