BACE-1 Inhibition for the Treatment of Neurodegenerative Diseases: Rationale, Assay Methodologies, and Reference Compounds

Inhibiting the activity of BACE1 is considered a potential therapeutic strategy for Alzheimer’s disease due to its role in the generation of amyloid-β (Aβ) peptide and, as consequence, in Aβ accumulation. Hence, BACE1, by controlling the rate-limiting step in the proteolysis of amyloid precursor protein (APP), is indeed responsible for the formation of senile plaques, which are one of the main histopathological manifestations of AD. In light of this, the development and application of reliable methods for the detection of BACE1 activity, and for the characterization of new molecular entities able to reduce enzymatic activity, is a fundamental task in the early stage of the AD drug discovery process. That is relevant for the fast selection of active compounds as well as for the comprehension of ligand binding mechanism resulting extremely useful in the forthcoming development. This chapter focuses on the in vitro methods to evaluate BACE1 activity and inhibition, with particular emphasis on fluorescence resonance energy transfer (FRET)-based methods. The description of the discussed methodologies is supposed to help in the selection of the most suitable assays to apply in the different steps of the drug discovery process: from the middle-/high-throughput screening (e.g., SPR, FRET) to the exploration of ligand-target interaction (e.g., NMR, MS).