Investigating the Interaction Between Characterized Amyloid-Beta Oligomers and the Prion Protein Receptor in Live Cells

Abstract

The devastating symptoms of Alzheimer's disease (AD) have been attributed to the aberrant aggregation of amyloid-β (Aβ) peptides generated from proteolytic cleavage of the transmembrane receptor, amyloid precursor protein (APP). Oligomers of the peptides amyloid-β1-40 (Aβ40) and amyloid-β1-42 (Aβ42) have been implicated in cytotoxicity and impaired cognitive function associated with AD1,2. Due to their heterogeneous nature, characterizing these oligomers on a molecular level and understanding the mechanism by which they induce cellular damage and death has proven to be difficult for conventional biochemical techniques. In this work, we use two color total internal reflection fluorescence microscopy first to characterize various preparations of Aβ oligomers on a molecular-level and then to explore the interactions of these well-characterized mixtures with live cells. Among the cellular systems examined include those expressing the prion protein receptor (PrPc) which, in recent studies, has been suggested to have a key role in mediating the toxic effects of Aβ oligomers3. From these studies we have not only been able to gain insight into the relationship between Aβ oligomers and PrPc on live cells but also have developed a methodology for examination of receptor-mediated Aβ neurotoxicity.1. Chiti, F. & Dobson, C.M. Protein misfolding, functional amyloid, and human disease. Annual Review of Biochemistry 75, 333-366 (2006).2. Cleary, J.P. et al. Natural oligomers of the amyloid-β protein specifically disrupt cognitive function. Nature Neuroscience 8, 79-84 (2005).3. Lauren, J., Gimbel, D.A., Nygaard, H.B., Gilbert, J.W. & Strittmatter, S.M. Cellular prion protein mediates impairment of synaptic plasticity by amyloid-β oligomers. Nature 457, 1128-1132 (2009).