Identification of Distinct N-terminal Truncated Forms of Prion Protein in Different Creutzfeldt-Jakob Disease Subtypes

Gianluigi Zanusso,Alessia Farinazzo,Frances Prelli,Michele Fiorini,Matteo Gelati,Sergio Ferrari,Pier Giorgio Righetti,Nicolò Rizzuto,Blas Frangione,Salvatore Monaco

doi:10.1074/jbc.m405468200

Gianluigi Zanusso, Alessia Farinazzo + Show 8 more

Open Access

PDF Available

https://doi.org/10.1074/jbc.m405468200

Copy DOI

Export

Save

Cite

Abstract
Highlights/Summary
Full-Text PDF
Similar Papers

Abstract

Listen

In prion diseases, the cellular prion protein (PrP(C)) is converted to an insoluble and protease-resistant abnormal isoform termed PrP(Sc). In different prion strains, PrP(Sc) shows distinct sites of endogenous or exogenous proteolysis generating a core fragment named PrP27-30. Sporadic Creutzfeldt-Jakob disease (sCJD), the most frequent human prion disease, clinically presents with a variety of neurological signs. As yet, the clinical variability observed in sCJD has not been fully explained by molecular studies relating two major types of PrP27-30 with unglycosylated peptides of 21 (type 1) and 19 kDa (type 2) and the amino acid methionine or valine at position 129. Recently, smaller C-terminal fragments migrating at 12 and 13 kDa have been detected in different sCJD phenotypes, but their significance remains unclear. By using two-dimensional immunoblot with anti-PrP antibodies, we identified two novel groups of protease-resistant PrP fragments in sCJD brain tissues. All sCJD cases with type 1 PrP27-30, in addition to MM subjects with type 2 PrP27-30, were characterized by the presence of unglycosylated PrP fragments of 16-17 kDa. Conversely, brain homogenates from patients VV and MV with type 2 PrP27-30 contained fully glycosylated PrP fragments, which after deglycosylation migrated at 17.5-18 kDa. Interestingly, PrP species of 17.5-18 kDa matched deglycosylated forms of the C1 PrP(C) fragment and were associated with tissue PrP deposition as plaque-like aggregates or amyloid plaques. These data show the presence of multiple PrP(Sc) conformations in sCJD and, in addition, shed new light on the correlation between sCJD phenotypes and disease-associated PrP molecules.

Highlights

Transmissible spongiform encephalopathies, or prion diseases, are mammalian neurodegenerative diseases leading to rapidly progressive neurological dysfunction [1]
The present findings show that: (i) novel truncated PrP fragments are detected in distinct molecular sporadic Creutzfeldt-Jakob disease (sCJD) subtypes; (ii) the combination of PrP27–30 and truncated PrP species identify three biochemical patterns of disease-associated prion protein; (iii) in MV2 and VV2 subtypes of sCJD, glycosylated molecules of the C1 fragment acquire biochemical hallmarks of PrPSc
Using sensitive protein separation techniques and Western blot with antibodies recognizing the C-terminal globular domain of prion protein, we have identified new protease-resistant PrP species in brain homogenates from sCJD subjects

Summary

Introduction

Transmissible spongiform encephalopathies, or prion diseases, are mammalian neurodegenerative diseases leading to rapidly progressive neurological dysfunction [1] They include sheep scrapie, bovine spongiform encephalopathies, and Creutzfeldt-Jakob disease in humans [1,2,3]. In these disorders, the host cellular prion protein (PrPC) is converted to an abnormal conformer (PrPSc) biochemically characterized by detergent insolubility and relative resistance to protease treatment [4]. We studied 32 subjects, with definite sCJD of all genotypes at PRNP codon 129 and with different PrPSc types, to characterize C-terminal PrPSc fragments in distinct disease phenotypes and host genotypes. We provide evidence that sCJD phenotypes with PrP amyloid plaques or plaque-like deposits are associated with pathological PrP species matching the so-called C1 PrPC fragment

Methods

Results

Conclusion