Taking A Different Tack With Amyloid-beta

Inhibiting the formation of amyloid-β, the peptide that clumps in the brains of patients with Alzheimer’s disease, has been a focus of drug designers for years. Rather than regulating amyloid-β directly, researchers at the University of Pennsylvania, led by Kurt R. Brunden, are now trying to control its production indirectly via an oxidative stress pathway in the body (ACS Chem. Neurosci., DOI: 10.1021/cn3000795). Neuroscientists have known that when amyloid-β clumps deposit in the brain, the peptide aggregates trigger formation of oxidized lipids such as isoprostane-2αIII. The Penn team,which also included chemists Carlo Ballatore and Amos B. Smith III, designed small molecules to block the thromboxane A₂-prostanoid (TP) receptor, a membrane protein whose activation by isoprostane-2αIII leads to an increase in amyloid-β production. Compounds that inhibit the TP receptor already existed, but they had a hard time penetrating the blood-brain barrier. By replacing a carboxylic acid on one of those molecules with a nonacidic oxazole or thiazole group, the researchers synthesized a batch of lead compounds (one shown) that entered the brain in mice and bound tightly to both human and mouse TP receptors in cells.