Alzheimer disease β-amyloid activity mimics cholesterol oxidase
Luigi Puglielli, … , Dora M. Kovacs, Ashley I. Bush
Luigi Puglielli, … , Dora M. Kovacs, Ashley I. Bush
Published September 1, 2005
Citation Information: J Clin Invest. 2005;115(9):2556-2563. https://doi.org/10.1172/JCI23610.
View: Text | PDF | Corrigendum
Research Article Neuroscience

Alzheimer disease β-amyloid activity mimics cholesterol oxidase

Abstract

The abnormal accumulation of amyloid β-peptide (Aβ) in the form of senile (or amyloid) plaques is one of the main characteristics of Alzheimer disease (AD). Both cholesterol and Cu2+ have been implicated in AD pathogenesis and plaque formation. Aβ binds Cu2+ with very high affinity, forming a redox-active complex that catalyzes H2O2 production from O2 and cholesterol. Here we show that Aβ:Cu2+ complexes oxidize cholesterol selectively at the C-3 hydroxyl group, catalytically producing 4-cholesten-3-one and therefore mimicking the activity of cholesterol oxidase, which is implicated in cardiovascular disease. Aβ toxicity in neuronal cultures correlated with this activity, which was inhibited by Cu2+ chelators including clioquinol. Cell death induced by staurosporine or H2O2 did not elevate 4-cholesten-3-one levels. Brain tissue from AD subjects had 98% more 4-cholesten-3-one than tissue from age-matched control subjects. We observed a similar increase in the brains of Tg2576 transgenic mice compared with nontransgenic littermates; the increase was inhibited by in vivo treatment with clioquinol, which suggests that brain Aβ accumulation elevates 4-cholesten-3-one levels in AD. Cu2+-mediated oxidation of cholesterol may be a pathogenic mechanism common to atherosclerosis and AD.

Authors

Luigi Puglielli, Avi L. Friedlich, Kenneth D.R. Setchell, Seiichi Nagano, Carlos Opazo, Robert A. Cherny, Kevin J. Barnham, John D. Wade, Simon Melov, Dora M. Kovacs, Ashley I. Bush

×

Figure 2

Options: View larger image (or click on image) Download as PowerPoint
Catalytic oxidation of cell-free and cellular cholesterol by Aβ:Cu2+. (A...
Catalytic oxidation of cell-free and cellular cholesterol by Aβ:Cu2+. (A) Production of 4-cholesten-3-one by Aβ42:Cu2+ (200 nM:400 nM) upon incubation for 60 minutes with increasing concentrations of nonoxidized cholesterol. Experiments were performed in triplicate. (B) Lineweaver-Burk transformation of the data shown in A. (C) Free cholesterol and (D) 4-cholesten-3-one in primary neurons after incubation for 2 days with Aβ42 (200 nM) and Aβ42:Cu2+ (200 nM:400 nM) with or without TETA (50 μM). Data are mean ± SD of 4 experiments. *P < 0.05.