Alzheimers disease (AD) is a neurodegenerative disease characterized by overproduction of β-amyloid peptides (Aβ) in the brain.The majority of these patients are sporadic late-onset AD (LOAD), and the cause of Aβoverproduction in these patients is still largely unknown.Aβ peptide is a product from sequential cleavage of β-amyloid precursor protein (APP) by β-and γ-secretases.Since β-and y-secretases reside in cholesterol-rich lipid rafts of plasma membrane, their activities are subjected to changes or levels of cellular cholesterol.