Generation of a new infectious recombinant prion: a model to understand Gerstmann\u2013Str\xe4ussler\u2013Scheinker syndrome

Saioa R Elezgarai,Natalia Fernández-Borges,Jesús R Requena,Hasier Eraña,Qingzhong Kong,Joaquín Castilla,Olivier Andréoletti,Jorge M Charco,Paula Saá,Alejandro M Sevillano,David Gil,Chafik Harrathi

doi:10.1038/s41598-017-09489-3

Abstract

Human transmissible spongiform encephalopathies (TSEs) or prion diseases are a group of fatal neurodegenerative disorders that include Kuru, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome (GSS), and fatal familial insomnia. GSS is a genetically determined TSE caused by a range of mutations within the prion protein (PrP) gene. Several animal models, based on the expression of PrPs carrying mutations analogous to human heritable prion diseases, support that mutations might predispose PrP to spontaneously misfold. An adapted Protein Misfolding Cyclic Amplification methodology based on the use of human recombinant PrP (recPMCA) generated different self-propagating misfolded proteins spontaneously. These were characterized biochemically and structurally, and the one partially sharing some of the GSS PrPSc molecular features was inoculated into different animal models showing high infectivity. This constitutes an infectious recombinant prion which could be an invaluable model for understanding GSS. Moreover, this study proves the possibility to generate recombinant versions of other human prion diseases that could provide a further understanding on the molecular features of these devastating disorders.

Highlights

Transmissible spongiform encephalopathies (TSEs) or prion diseases are a group of rare progressive neurodegenerative disorders distinguished by long incubation periods and often associated with severe spongiform vacuolation of the central nervous system and neuronal loss[1]
A total of 9 amino acid substitutions in the human prion protein gene (PRNP) gene associated with the most frequent genetic human TSEs (GSS, genetic Creutzfeldt-Jakob disease (gCJD) and Fatal Familial Insomnia (FFI)) were selected in order to evaluate their effect on protein misfolding
Taking advantage of our experience with brain-protein misfolding cyclic amplification (PMCA), we developed an in vitro method to evaluate the susceptibility to misfolding of certain pathogenic mutations in association with the two polymorphic variants of the human PrP at residue 129 (M/V)

Summary

Introduction

Transmissible spongiform encephalopathies (TSEs) or prion diseases are a group of rare progressive neurodegenerative disorders distinguished by long incubation periods and often associated with severe spongiform vacuolation of the central nervous system and neuronal loss[1]. The causative agent of TSEs is an aberrantly folded prion protein (PrPSc) which transforms the normal cellular prion protein (PrPC) into a transmissible isoform[2]. These diseases have been described in a wide range of mammalian species including humans. Pirisinu et al demonstrated that GSS prion strains associated with different mutations showed low transmissibility in general and was dependent on the presence in the inoculum of a classical PrPSc pattern by Western Blot after proteinase-K treatment as opposed to containing only lower molecular weight (Mw) “atypical” PK-resistant fragments[14]. It is accepted that pathogenic mutations make PrP more prone to misfolding, the intrinsic mechanism by which each mutation is responsible for the development of different prion diseases with specific clinical profiles and pathogeneses is still unknown

Methods

Results

Conclusion