Novel method for classification of prion diseases by detecting PrP^res signal patterns from formalin-fixed paraffin-embedded samples

ABSTRACT

Prion disease is an infectious and fatal neurodegenerative disease. Western blotting (WB)-based identification of proteinase K (PK)-resistant prion protein (PrP^res) is considered a definitive diagnosis of prion diseases. In this study, we aimed to detect PrP^res 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 PrP^res signal was observed, with antibodies specific for type 1 and type 2 PrP^res 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 PrP^res bands at 8–9 kDa and smear bands, respectively. However, an antibody specific for the C-terminus presented as smears in GSS, with no PrP^res detected in GPIALP. It was difficult to detect PrP^res in V180I CJD. Collectively, our findings demonstrate the possibility of detecting PrP^res 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.

KEYWORDS:

• FFPE
• PK-resistant prion protein
• Prion disease
• Sporadic Creutzfeldt–Jakob disease
• western blotting

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.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.