Anti‐amyloidogenic effect of BACE1 expression lowering compound identified using high‐throughput gene promoter assay

Abstract

AbstractBackgroundAccumulation of Aβ in a brain is one of the pathological hallmarks of Alzheimer’s disease (AD). Aβ is generated through sequential cleavage of amyloid precursor protein (APP) by β‐secretase (BACE1) and γ‐secretase complex. BACE1 is one of the crucial targets for AD given that BACE1 expression is significantly upregulated in AD patients compared with non‐AD. However, direct and complete inhibition of BACE1 activity can cause unpredictable or unintended effects because of numerous physiological substrates of BACE1.MethodWe screened small compounds, including drugs approved by the U.S. Food and Drug Administration to identify medicines that reduce promoter activity of BACE1. TG reduced the levels of BACE1 protein and mRNA in APP‐SH‐SY5Y cells. In order to confirm the effect of TG regulating the expression BACE1, we constructed the RFP (BACE1 expression indicator) ‐GFP (cell body) U2OS cell line and compared the TG and analogs. After administration of TG,we carried out Morris Water Maze(MWM) test in APP/PS1 AD model mice. We did immunofluorescence assay in each group of mouse brains. We conducted an ELISA assay to determine quantitative changes in Aβ accumulation.ResultWe have found a new candidate drug that reduces promoter activity, mRNA, and protein levels of BACE1 in neuronal cells. We have confirmed that the drug decreases the BACE1 gene expression, prevents accumulation of Aβ, and improves cognitive function in APP/PS1 transgenic mice.ConclusionThe ability of this compound reverses a wide range of deficits suggests that BACE1 expression reducing agents may have therapeutic utility in the treatment of AD