APP and tauopathy: The most popular models are based on overexpression of human amyloid precursor protein (APP), presenilin (PSEN) [part of the γ-secretase complex involved in the cleavage of APP into amyloid-β (Aβ)] and tau, alone or in combination, to trigger accumulation of high levels of Aβ into plaques as well as the development of tauopathy (Spires and Hyman, 2005).