Small Ruminant Nor98 Prions Share Biochemical Features with Human Gerstmann-Sträussler-Scheinker Disease and Variably Protease-Sensitive Prionopathy

Abstract

Prion diseases are classically characterized by the accumulation of pathological prion protein (PrPSc) with the protease resistant C-terminal fragment (PrPres) of 27–30 kDa. However, in both humans and animals, prion diseases with atypical biochemical features, characterized by PK-resistant PrP internal fragments (PrPres) cleaved at both the N and C termini, have been described. In this study we performed a detailed comparison of the biochemical features of PrPSc from atypical prion diseases including human Gerstmann-Sträussler-Scheinker disease (GSS) and variably protease-sensitive prionopathy (VPSPr) and in small ruminant Nor98 or atypical scrapie. The kinetics of PrPres production and its cleavage sites after PK digestion were analyzed, along with the PrPSc conformational stability, using a new method able to characterize both protease-resistant and protease-sensitive PrPSc components. All these PrPSc types shared common and distinctive biochemical features compared to PrPSc from classical prion diseases such as sporadic Creutzfeldt-Jakob disease and scrapie. Notwithstanding, distinct biochemical signatures based on PrPres cleavage sites and PrPSc conformational stability were identified in GSS A117V, GSS F198S, GSS P102L and VPSPr, which allowed their specific identification. Importantly, the biochemical properties of PrPSc from Nor98 and GSS P102L largely overlapped, but were distinct from the other human prions investigated. Finally, our study paves the way towards more refined comparative approaches to the characterization of prions at the animal–human interface.

Current understanding of PrnP Genetics: A tool for Molecular Assisted Selection in Sheep Populations (A review)

“…This biochemical signature, unique among animal TSEs, is reminiscent of PrP res observed in human prion disorders such as GSS and VPSPr (Pirisinu et al, 2013).…”

“…The biochemical feature in classical scrapie is the typical PrP 27-30 profile of the prion protein following treatment at all concentrations of K proteinase, i.e three bands corresponding to N terminally truncated diglycosylated, monoglyco sylated and non glycosylated PrP res (Oesch et al,1985;Pirisinu et al, 2013).…”

“…Current understanding of PrnP Genetics: A tool for Molecular Assisted Selection in Sheep Populations The latest studies for discriminating prion strains involved in TSE in animals from those in humans have brought to light the similarity of molecular profile of isolates Nor98 (from Norway and Italy) with that characteristic for the GSS syndrome (Gerstmann-Straussler-Sheinker Syndrom) and that of the newly described human sporadic prion disorder, variably protease sensitive prionopathy (VPSPr), after treatment with 200µg/ ml PK in WB analysis (Pirisinu et al, 2013).…”

“…In the latest studies for the molecular discrimination of TSE agents, in classical scrapie the electrophoretic profile remains characterized by the same three fragments, corresponding to N terminally truncated diglycosylated, monoglyco sylated and non glycosylated PrP res , whatever the PK concentrations, while in the atypical scrapie the Nor98 profile is different depending on the PK concentrations (Pirisinu et al, 2013).…”

“…Molecular criteria used to discriminate BSE from scrapie are based on the low molecular weight of proteinase K-treated PrP Sc (PrP res ), a high proportion of the diglycosylated PrP Sc , and poor or absent binding with antibodies directed at N-terminal epitopes (Pirisinu et al, 2013). For atypical scrapie cases four protein bands are visualised by Western immunoblotting, ranging from 19 kDa (unglycosylated PrP res ) to 27 kDa (diglycosylated PrP res ) with a fourth band (lower than other TSEs) below 15 kDa ( OIE, 2009).…”