ATR–FTIR, a new tool to analyze the oligomeric content of Aβ samples in the presence of apolipoprotein E isoforms
Issue title: From Molecule to Tissue: XIII European Conference on the Spectroscopy of Biological Molecules, Palermo, Italy, August 28–September 2, 2009, Part 2 of 2
Affiliations: Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium
Note: [] Corresponding author: Emilie Cerf, Structure and Function of Biological Membranes, Université Libre de Bruxelles, Boulevard du Triomphe CP206/2, Brussels, 1050, Belgium. Tel.: +32 2650 5366; Fax: +32 2650 5382; E-mail: [email protected].
Abstract: Alzheimer's disease (AD) is a neurodegenerative disorder caused by the aggregation of the amyloid-beta peptide (Aβ), leading to amyloid plaques deposition in the brain. Although Aβ aggregation pathway still remains unclear, recent studies point out the enhanced toxicity of oligomers compared to fibrils. The E4 isoform of apolipoprotein E (ApoE) is the major risk factor in AD as people carrying one ε4 allele have significantly higher chances to develop the disease. Nevertheless, this phenomenon is still poorly understood. Our group has shown that attenuated total reflection Fourier-transform infrared spectroscopy (ATR–FTIR) could discriminate between Aβ42 oligomers and fibrils. Indeed, oligomers display anti-parallel β-sheet spectral components while fibrils are characterized by a parallel β-sheet organization. Using those spectral features to analyze the oligomeric content of our samples, we studied the influence of ApoE on Aβ42 aggregation. Our experiments demonstrated that ApoE3 increased the amount of Aβ42 oligomers in the sample. We can thus determine the proportion of Aβ oligomers in the presence of another compound in the sample. We plan to use ATR–FTIR to assess the effects of the other isoforms of ApoE on Aβ aggregation. Moreover, this could be extended to study the influence of other molecules or proteins on Aβ aggregation.
Keywords: Amyloid-beta, apolipoprotein E, oligomers, ATR–FTIR
DOI: 10.3233/SPE-2010-0439
Journal: Spectroscopy, vol. 24, no. 3-4, pp. 245-249, 2010
