Preferential Recruitment of Conformationally Distinct Amyloid-β Oligomers by the Intrinsically Disordered Region of the Human Prion Protein

Abstract

Soluble oligomeric species of the amyloid-β (Aβ) peptide exhibit pronounced neurotoxic effects in Alzheimer’s disease. Recent studies have indicated that the prion protein (PrP) is one of the cell-surface receptors, so-called a bad receptor, of Aβ oligomers that mediates downstream cellular toxicity. A rational classification of Aβ oligomers on the basis of conformation indicates that there are two distinct types of oligomers, namely, prefibrillar and fibrillar oligomers that are positive to A11 and OC conformation-dependent antibodies, respectively. The mechanism of heterotypic assembly of conformationally distinct oligomers and PrP is poorly understood. In this work, using an array of biophysical and biochemical tools, we dissect the molecular mechanism of the interaction of A11- and OC-positive Aβ42 oligomers with human PrP. Using site-specific binding titrations, we show that the recruitment of Aβ oligomers primarily occurs via the electrostatic interaction between the N-terminal intrinsically disordered region of PrP and Aβ oligomers. Our results demonstrate that OC-positive fibrillar oligomers possessing in-register parallel β-sheet packing displayed ∼30 times stronger binding with PrP compared to A11-positive oligomers. We also show that these OC-positive oligomers exacerbate their toxic effects on mammalian cells upon binding to PrP. On the contrary, the addition of PrP does not alter the toxicity exhibited by A11-positive oligomers. Our findings suggest that strategies targeting the interaction between PrP and OC-positive oligomers, which have been shown to be highly concentrated in the vicinity of amyloid plaques, may have therapeutic potential against Alzheimer’s disease.

Structural details of amyloid β oligomers in complex with human prion protein as revealed by solid-state MAS NMR spectroscopy

“…Instead, the high degree of β-strand content indicates that Aβ oligos already contain Aβ monomer units that have at least in part the same secondary structure as in fibrils or protofibrils, but probably differ in tertiary structure. This phenomenon has already been observed in early stage Aβ oligomers (8,72) and is supported by the finding that huPrP-mediated toxicity depends partially on high-molecularweight fibrillar-like Aβ oligo (59,60). Assuming that the Aβ oligo preparation yielded a heterogeneous collection of fibril-like conformers in terms of secondary structure, of which most if not all were obviously elongation incompetent when trapped by adding huPrP, one would expect that the solid-state NMR resonances of Aβ oligo in complex with huPrP are the sum of the resonances of different fibril conformations together with resonances from Aβ units that experience different environments due to edge effects and/or huPrP interaction.…”

“…Aside from the protective role of soluble huPrP in AD, membrane-anchored huPrP is mediating neurotoxicity of Aβ(1-42) oligo (19,24,25) via Fyn-kinase (26,27) or NMDA receptor pathways (57). Although Aβ(1-42) oligo toxicity is not solely dependent on huPrP (28-31), it has been shown that especially small Aβ(1-42) oligo (58) and high-molecular-weight Aβ(1-42) oligo (59,60) mediate toxicity by huPrP. To target this interaction efficient inhibitors might prevent Aβ(1-42) oligos ' detrimental effects.…”

Sub-stoichiometric Hsp104 regulates the genesis and persistence of self-replicable amyloid seeds of a yeast prion protein

“…To further reconfirm the spherical entities as amyloid oligomers, we probed the NM-Hsp104 aggregation reactions using A11 antibody that is specific for oligomers. 33,34,35 In the sample spotted after 7h from the commencement of the reaction, we detected a weak signal indicating the existence of a low fraction of oligomeric species in the presence of a low concentration of Hsp104 but not in the absence of Hsp104. This weak A11 activity in the presence of Hsp104 disappeared after 30h due to the conversion of all oligomeric species into matured fibrils (Figure 1g).…”

Spatiotemporal Modulations in Heterotypic Condensates of Prion and α-Synuclein Control Phase Transitions and Amyloid Conversion

“…PrP 23-144 (Y145Stop), PrP 112-231, and single cysteine variants of full-length PrP (W31C and W99C) were used as described previously. 63,90 Recombinant full-length human α-Syn (1-140) plasmid cloned in vector pT7.7 was transformed in BL21(DE3)pLysS. 91 α-Syn (1-102) (N103Stop) and α-Syn (1-132) (Y133Stop) were created using the full-length α-Syn plasmid.…”

“…91 Recombinant prion protein constructs were overexpressed and purified using previously published protocols. 63,90 The purified proteins were refolded using the PD10 column in 14 mM MES buffer, pH 6.8. Recombinant α-Syn constructs except 103Stop were purified using the anion-exchange chromatography as described previously.…”