Allelic Origin of Protease-Sensitive and Protease-Resistant Prion Protein Isoforms in Gerstmann-Sträussler-Scheinker Disease with the P102L Mutation

• Published in: PloS one Vol. 7; no. 2; p. e32382
• Main Authors: Monaco, Salvatore, Fiorini, Michele, Farinazzo, Alessia, Ferrari, Sergio, Gelati, Matteo, Piccardo, Pedro, Zanusso, Gianluigi, Ghetti, Bernardino
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 23.02.2012; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Alleles; Antibodies; Biology; Centrifugation, Density Gradient; Creutzfeldt-Jakob disease; Degeneration; Dementia; Diagnostic systems; Female; Fragmentation; Gerstmann-Straussler-Scheinker Disease - genetics; Gerstmann-Straussler-Scheinker Disease - metabolism; Humans; Immunohistochemistry; Immunohistochemistry - methods; Insomnia; Isoelectric Focusing; Isoforms; Laboratories; Leucine; Male; Medicine; Middle Aged; Models, Genetic; Morphology; Mutation; Neuropathology; Paraffin; Peptide Hydrolases - metabolism; Peptides; Phenotype; Phenotypes; Point Mutation; Positron-Emission Tomography - methods; Prion protein; Proline; Propagation; Protease; Protein Conformation; Protein purification; Proteinase; Proteins; Proteolysis; PrPSc Proteins - genetics; Separation techniques; Sucrose - chemistry; Transgenic animals; Western blotting; Italy; Indiana; Monaco; United States > US; Indianapolis Indiana
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0032382

Gerstmann-Sträussler-Scheinker (GSS) disease is a dominantly inherited prion disease associated with point mutations in the Prion Protein gene. The most frequent mutation associated with GSS involves a proline-to-leucine substitution at residue 102 of the prion protein, and is characterized by marked variability at clinical, pathological and molecular levels. Previous investigations of GSS P102L have shown that disease-associated pathological prion protein, or PrP(Sc), consists of two main conformers, which under exogenous proteolysis generates a core fragment of 21 kDa and an internal fragment of 8 kDa. Both conformers are detected in subjects with spongiform degeneration, whereas only the 8 kDa fragment is recovered in cases lacking spongiosis. Several studies have reported an exclusive derivation of protease-resistant PrP(Sc) isoforms from the mutated allele; however, more recently, the propagation of protease-resistant wild-type PrP(Sc) has been described. Here we analyze the molecular and pathological phenotype of six GSS P102L cases characterized by the presence of 21 and 8 kDa PrP fragments and two subjects with only the 8 kDa PrP fragment. Using sensitive protein separation techniques and Western blots with antibodies differentially recognizing wild-type and mutant PrP we observed a range of PrP(Sc) allelic conformers, either resistant or sensitive to protease treatment in all investigated subjects. Additionally, tissue deposition of protease-sensitive wild-type PrP(Sc) molecules was seen by conventional PrP immunohistochemistry and paraffin-embedded tissue blot. Our findings enlarge the spectrum of conformational allelic PrP(Sc) quasispecies propagating in GSS P102L thus providing a molecular support to the spectrum of disease phenotypes, and, in addition, impact the diagnostic role of PrP immunohistochemistry in prion diseases.