APOE and amyloidosis: To identify synergistic pathological interactions of APOE4 and Aβ under endogenous regulation and physiological levels during preclinical stages of amyloidosis, we bred human APOE4-KI and AppNLF-KI mice to obtain APOE4/E4 (E4), AppNLF/NLF (NLF), APOE4/E4:AppNLF/NLF (E4NLF), and wild-type (WT) littermates.