Evidence of redox-active iron formation following aggregation of ferrihydrite and the Alzheimer's disease peptide ß-amyloid.

Abstract

Recent work has demonstrated increased levels of redox-active iron biominerals in Alzheimer's disease (AD) tissue. However, the origin, nature, and role of iron in AD pathology remains unclear. Using X-ray absorption, X-ray microspectroscopy, and electron microscopy techniques, we examined interactions between the AD peptide ß-amyloid (Aß) and ferrihydrite, which is the ferric form taken when iron is stored in humans. We report that Aß is capable of reducing ferrihydrite to a pure iron(II) mineral where antiferromagnetically ordered Fe(2+) cations occupy two nonequivalent crystal symmetry sites. Examination of these iron(II) phases following air exposure revealed a material consistent with the iron(II)-rich mineral magnetite. These results demonstrate the capability of Aß to induce the redox-active biominerals reported in AD tissue from natural iron precursors. Such interactions between Aß and ferrihydrite shed light upon the processes of AD pathogenesis, while providing potential targets for future therapies.

• Acceptance Date: Feb 21, 2014
• Publication Date: Feb 21, 2014
• Journal: Inorganic Chemistry
• Print ISSN: 0020-1669
• Publisher: American Chemical Society
• Pages: 2803 - 2809
• DOI: https://doi.org/10.1021/ic402406g
• Publisher URL: https://pubs.acs.org/doi/10.1021/ic402406g