Deferiprone Reduces Amyloid-β and Tau Phosphorylation Levels but not Reactive Oxygen Species Generation in Hippocampus of Rabbits Fed a Cholesterol-Enriched Diet

Article type: Research Article

Authors: Prasanthi, Jaya R.P.^a | Schrag, Matthew^{b; c} | Dasari, Bhanu^a | Marwarha, Gurdeep^a | Dickson, April^b | Kirsch, Wolff M.^b | Ghribi, Othman^{a; *}

Affiliations: [a] Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA | [b] Department of Biochemistry and Neurosurgery Center for Research, Training and Education, Loma Linda University, Loma Linda, CA, USA | [c] Department of Neurology, Yale University, New Haven, CT, USA

Correspondence: [*] Correspondence to: Othman Ghribi, Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Grand Forks, ND 58202, USA. Tel.: +1 701 777 2522; Fax: +1 701 777 4490; E-mail: [email protected].

Abstract: Accumulation of amyloid-β (Aβ) peptide and the hyperphosphorylation of tau protein are major hallmarks of Alzheimer's disease (AD). The causes of AD are not well known but a number of environmental and dietary factors are suggested to increase the risk of developing AD. Additionally, altered metabolism of iron may have a role in the pathogenesis of AD. We have previously demonstrated that cholesterol-enriched diet causes AD-like pathology with iron deposition in rabbit brain. However, the extent to which chelation of iron protects against this pathology has not been determined. In this study, we administered the iron chelator deferiprone in drinking water to rabbits fed with a 2% cholesterol diet for 12 weeks. We found that deferiprone (both at 10 and 50 mg/kg/day) significantly decreased levels of Aβ40 and Aβ42 as well as BACE1, the enzyme that initiates cleavage of amyloid-β protein precursor to yield Aβ. Deferiprone also reduced the cholesterol diet-induced increase in phosphorylation of tau but failed to reduce reactive oxygen species generation. While deferiprone treatment was not associated with any change in brain iron levels, it was associated with a significant reduction in plasma iron and cholesterol levels. These results demonstrate that deferiprone confers important protection against hypercholesterolemia-induced AD pathology but the mechanism(s) may involve reduction in plasma iron and cholesterol levels rather than chelation of brain iron. We propose that adding an antioxidant therapy to deferiprone may be necessary to fully protect against cholesterol-enriched diet-induced AD-like pathology.

Keywords: Alzheimer's disease, cholesterol, deferiprone, iron, oxidative stress, tau

DOI: 10.3233/JAD-2012-111346

Journal: Journal of Alzheimer's Disease, vol. 30, no. 1, pp. 167-182, 2012