Lithium ions display weak interaction with amyloid-beta (Aß) peptides and have minor effects on their aggregation.

ABSTRACT

Alzheimer's disease (AD) is an incurable disease and the main cause of age-related dementia worldwide, despite decades of research. Treatment of AD with lithium (Li) has showed promising results, but the underlying mechanism is unclear. The pathological hallmark of AD brains is deposition of amyloid plaques, consisting mainly of amyloid-ß (Aß) peptides aggregated into amyloid fibrils. The plaques contain also metal ions of e.g. Cu, Fe, and Zn, and such ions are known to interact with Aß peptides and modulate their aggregation and toxicity. The interactions between Aß peptides and Li+ ions have however not been well investigated. Here, we use a range of biophysical techniques to characterize in vitro interactions between Aß peptides and Li+ ions. We show that Li+ ions display weak and non-specific interactions with Aß peptides, and have minor effects on Aß aggregation. These results indicate that possible beneficial effects of Li on AD pathology are not likely caused by direct interactions between Aß peptides and Li+ ions.