Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.
Skip to main content

The beta-amyloid (Abeta) peptide, a major component of senile plaques in Alzheimer's disease brain, has been shown previously to undergo a process of polymerization to produce neurotoxic forms of amyloid. Recent literature has attempted to define precisely the form of Abeta responsible for its neurodegenerative properties. In the present study we describe a novel density-gradient centrifugation method for the isolation and characterization of structurally distinct polymerized forms of Abeta peptide. Fractions containing protofibrils, fibrils, sheet structures and low molecular mass oligomers were prepared. The fractionated forms of Abeta were characterized structurally by transmission electron microscopy. The effects on cell viability of these fractions was determined in the B12 neuronal cell line and hippocampal neurons. Marked effects on cell viability in the cells were found to correspond to the presence of protofibrillar and fibrillar structures, but not to monomeric peptide or sheet-like structures of polymerized Abeta. Biological activity correlated with a positive reaction in an immunoassay that specifically detects protofibrillar and fibrillar Abeta; those fractions that were immunoassay negative had no effect on cell viability. These data suggest that the effect of Abeta on cell viability is not confined to a single conformational form but that both fibrillar and protofibrillar species have the potential to be active in this assay.

Type

Journal article

Journal

Biochem J

Publication Date

15/05/2000

Volume

348 Pt 1

Pages

137 - 144

Keywords

Amyloid beta-Peptides, Animals, Cells, Cultured, Centrifugation, Density Gradient, Chemical Fractionation, Electrophoresis, Polyacrylamide Gel, Hippocampus, Immunoassay, Peptide Fragments, Rats, Rats, Sprague-Dawley