C-terminal peptides coassemble into A 42 oligomers and protect neurons against A 42-induced neurotoxicity

Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 10/2008; 105(37):14175-80. DOI: 10.1073/pnas.0807163105
Source: PubMed


Alzheimer's disease (AD) is an age-related disorder that threatens to become an epidemic as the world population ages. Neurotoxic oligomers of Abeta42 are believed to be the main cause of AD; therefore, disruption of Abeta oligomerization is a promising approach for developing therapeutics for AD. Formation of Abeta42 oligomers is mediated by intermolecular interactions in which the C terminus plays a central role. We hypothesized that peptides derived from the C terminus of Abeta42 may get incorporated into oligomers of Abeta42, disrupt their structure, and thereby inhibit their toxicity. We tested this hypothesis using Abeta fragments with the general formula Abeta(x-42) (x = 28-39). A cell viability screen identified Abeta(31-42) as the most potent inhibitor. In addition, the shortest peptide, Abeta(39-42), also had high activity. Both Abeta(31-42) and Abeta(39-42) inhibited Abeta-induced cell death and rescued disruption of synaptic activity by Abeta42 oligomers at micromolar concentrations. Biophysical characterization indicated that the action of these peptides likely involved stabilization of Abeta42 in nontoxic oligomers. Computer simulations suggested a mechanism by which the fragments coassembled with Abeta42 to form heterooligomers. Thus, Abeta(31-42) and Abeta(39-42) are leads for obtaining mechanism-based drugs for treatment of AD using a systematic structure-activity approach.

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    • "Another cell viability screen [21] identified Ab 31–42 and Ab 39–42 as the most potent inhibitors. Biophysical characterisation [21] indicated that the action of these peptides likely involved stabilisation of Ab 42 into nontoxic oligomers. Therefore, in this study we focused on the region 32–42 to design mutations in Ab 42 peptide that would inhibit aggregation of the monomeric form and/or stabilise the tetramer in nontoxic form. "
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