Neurodegeneration: Aβ peptide clearance in Alzheimer’s disease

Alzheimer’s disease (AD) is the most common form of dementia. This incurable and progressive disease is closely associated with extracellular amyloid beta (Aβ) peptides that aggregate to form plaques and neurofibrillary tangles in the gray matter of the brain. Plaques and tangles are important for the neuropathological verification of AD, but their role in disease pathogenesis is unclear. Luheshi, Hoyer et al. evaluated a small stable protein called Zaβ3 that specifically binds to Aβ peptides with high affinity. When expressed in the brain of Drosophila models of AD, Zaβ3 sequesters Aβ peptide and inhibits its aggregation and toxicity. AD flies expressing Zaβ3 lived longer than AD controls and retained significantly less Aβ peptide, suggesting that enhanced clearance of the protein reduces disease pathology. This fly model demonstrates a direct role for Aβ plaque formation in neurodegeneration. Since small molecule binding to Aβ peptide reduces its aggregation and toxicity, and extends survival, there could be potential for drugs that promote Aβ peptide clearance in AD patients.