MAPT and Alzheimer disease: The mechanisms involve sophisticated polypharmacodynamic effects: direct targeting of core AD pathologies (reducing Aβ aggregation and inhibiting Tau hyperphosphorylation); neuroprotection via suppression of mitochondrial apoptosis, oxidative stress, and neuroinflammation; modulation of critical neurotransmitter systems (serotonergic and glutamatergic, the latter potentiated by metabolite-induced GluK receptor upregulation); and enhancement of synaptic plasticity and neuronal survival.