ABSTRACT
Prion disease is an infectious and fatal neurodegenerative disease. Western blotting (WB)-based identification of proteinase K (PK)-resistant prion protein (PrPres) is considered a definitive diagnosis of prion diseases. In this study, we aimed to detect PrPres using formalin-fixed paraffin-embedded (FFPE) specimens from cases of sporadic Creutzfeldt–Jakob disease (sCJD), Gerstmann–Sträussler–Scheinker disease (GSS), glycosylphosphatidylinositol-anchorless prion disease (GPIALP), and V180I CJD. FFPE samples were prepared after formic acid treatment to inactivate infectivity. After deparaffinization, PK digestion was performed, and the protein was extracted. In sCJD, a pronounced PrPres signal was observed, with antibodies specific for type 1 and type 2 PrPres exhibited a strong or weak signals depending on the case. Histological examination of serial sections revealed that the histological changes were compatible with the biochemical characteristics. In GSS and GPIALP, prion protein core-specific antibodies presented as PrPres bands at 8–9 kDa and smear bands, respectively. However, an antibody specific for the C-terminus presented as smears in GSS, with no PrPres detected in GPIALP. It was difficult to detect PrPres in V180I CJD. Collectively, our findings demonstrate the possibility of detecting PrPres in FFPE and classifying the prion disease types. This approach facilitates histopathological and biochemical evaluation in the same sample and is safe owing to the inactivation of infectivity. Therefore, it may be valuable for the diagnosis and research of prion diseases.
Acknowledgments
This work was funded by a Grant of The Clinical Research Promotion Foundation (2021). The authors greatly appreciate the patients and their families for their collaboration with this study. We would also like to thank Tetsuyuki Kitamoto (Department of Neurological Science, Tohoku University Graduate School of Medicine, Miyagi, Japan) for genetic test, and Kyoko Iinuma (Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan) and Toru Iwaki (Kyushu University, Fukuoka, Japan) for technical and conceptual assistance, and Editage (www.editage.com) for the English language editing.
Author Contribution
Sachiko Koyama and Hiroyuki Honda conceptualized the study, conducted examinations, analysed the data, and wrote manuscript. Kaoru Yagita, Hideomi Hamasaki, Hideko Noguchi and Masahiro Shijo, contributed to the data analysis and examinations. Kosuke Matsuzono, Kei-Ichiro Takase, Keita Kai, Shin-Ichi Aishima, Kyoko Itoh Toshiharu Ninomiya and Naokazu Sasagasako, provided the autopsy samples and clinical data.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Data availability statement
Data supporting the findings of this study are available from the corresponding author upon reasonable request.