APP and Alzheimer disease: ApoE may act both as an AD inhibitor and promoter [4, 9], profoundly affecting Aβ metabolism through several pathways: (1) Promoting APP Expression: ApoE4 enhances APP transcription directly or via signaling pathways like extracellular signal-regulated kinase (ERK), nuclear factor-κB (NF-κB), and C/EBPβ [10, 11].