title: High pressure induces scrapie-like prion protein misfolding and amyloid fibril formation.
abstract: Our understanding of conformational conversion of proteins in diseases is essential for any diagnostic and therapeutic approach. Although not fully understood, misfolding of the prion protein (PrP) is implicated in the pathogenesis of prion diseases. Despite several efforts to produce the pathologically misfolded conformation in vitro from a recombinant PrP, no positive result has yet been obtained. Within the "protein-only hypothesis", the reason for this hindrance may be that the experimental conditions used did not allow selection of the pathway adopted in vivo resulting in conversion into the infectious form. Here, using a pressure perturbation approach, we show that recombinant PrP is converted to a novel misfolded conformer, which is prone to aggregate and ultimately form amyloid fibrils. A short incubation at high pressure (600 MPa) of the truncated form of hamster prion protein (SHaPrP(90-231)) resulted in the formation of pre-amyloid structures. The mostly globular aggregates were characterized by ThT and ANS binding, and by a beta-sheet-rich secondary structure. After overnight incubation at 600 MPa, amyloid fibrils were formed. In contrast to pre-amyloid structures, they showed birefringency of polarized light after Congo red staining and a strongly decreased ANS binding capacity, but enhanced ThT binding. Both aggregate types were resistant to digestion by PK, and can be considered as potential scrapie-like forms or precursors. These results may be useful for the search for compounds preventing pathogenic PrP misfolding and aggregation.
authors.affiliation: Université de Montpellier 2, EA3763, Place Eugène Bataillon, F-34095 Montpellier cédex 5, France.
authors.forename: Joan
authors.initials: J
authors.lastname: Torrent
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Alvarez-Martinez
authors.forename: Marie-Cécile
authors.initials: MC
authors.lastname: Harricane
authors.forename: Frédéric
authors.initials: F
authors.lastname: Heitz
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Liautard
authors.forename: Claude
authors.initials: C
authors.lastname: Balny
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lange
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D000817:Anilino Naphthalenesulfonates / Q000494:pharmacology; D000818:Animals; D003224:Congo Red; D006224:Cricetinae; D019286:Endopeptidase K / Q000378:metabolism; D005456:Fluorescent Dyes / Q000494:pharmacology; D011312:Pressure; D017096:Prion Diseases / Q000473:pathology; D011328:Prions / Q000737:chemistry* / Q000648:ultrastructure; D011487:Protein Conformation / Q000187:drug effects; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000682:Amyloid; D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D011328:Prions; D011994:Recombinant Proteins; D003224:Congo Red; C027132:1-anilino-8-naphthalenesulfonate; D019286:Endopeptidase K