PSEN1 and Alzheimer disease: PS1 and PS2 conditional double knockout (cDKO) mice showed severe AD-like neurodegenerative phenotypes, including forebrain degeneration (e.g., cortical shrinkage), synaptic dysfunction, tau hyperphosphorylation and age-dependent memory decline (Feng et al., 2004; Saura et al., 2004), also exhibited significantly increased inflammatory responses (Beglopoulos et al., 2004; Jiang et al., 2009).