No conflicts of interest were declared.
Development of oligomeric prion-protein aggregates in a mouse model of prion disease†
Article first published online: 11 MAY 2009
Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The Journal of Pathology
Volume 219, Issue 1, pages 123–130, September 2009
How to Cite
Sasaki, K., Minaki, H. and Iwaki, T. (2009), Development of oligomeric prion-protein aggregates in a mouse model of prion disease. J. Pathol., 219: 123–130. doi: 10.1002/path.2576
- Issue published online: 7 AUG 2009
- Article first published online: 11 MAY 2009
- Accepted manuscript online: 11 MAY 2009 12:00AM EST
- Manuscript Accepted: 5 MAY 2009
- Manuscript Revised: 31 MAR 2009
- Manuscript Received: 13 FEB 2009
- Ministry of Health, Labour and Welfare, Japan. Grant Number: H19-nanchi-ippan-006
- Japan Society for the Promotion of Science. Grant Number: 19500309
- transimissible spongiform encephalopathy;
- Creutzfeldt–Jakob disease;
- mouse model
In prion diseases the normal cellular isoform of prion protein (PrP), denoted PrPC, is converted into an abnormal, pathogenic isoform of PrP (PrPSc). Diagnostic tools for prion diseases are conventionally based on the detection of protease-resistant PrP (PrPres) after proteinase K digestion. However, recent studies have revealed that protease-sensitive abnormal PrP (sPrPSc) also exists in significant amounts in brains suffering from prion diseases. Here, we designed a simplified size-exclusion gel chromatography assay, using disposable spin columns to examine PrP aggregates in the course of the disease, without proteinase K digestion. Brain homogenates of NZW mice, inoculated intracranially with Fukuoka-1 strain, and which died at around 120 days post-inoculation, were assayed by this gel-fractionation method and eluted PrP molecules in each fraction were detected by western blot analysis. Oligomeric PrP molecules were well separated from monomers, as predicted. A conventional protease-digestion assay was also performed to detect PrPres and revealed that the ratio of PrPres to total PrP increased drastically from 105 days. However, the increase of PrP oligomers became significant from 90 days. These PrP oligomers in the early disease stage would, therefore, be sPrPSc molecules that might affect the disease pathology, such as spongiform change and abnormal PrP deposition. We also observed that the resistance of PrP oligomers to proteinase K and insolubility in phosphotungstic acid precipitation increased with disease progression, which suggests that PrP oligomers are not clearly distinguished from cellular PrP or PrPres but may overlap in a continuous spectrum. Our study casts light on the ambiguity of the definition of PrPSc and indicates that the abnormality of PrP molecules should be determined from various perspectives, more than protease resistance. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.