Differentiated cultures of an immortalized human neural progenitor cell line do not replicate prions despite PrP^C overexpression

ABSTRACT

Prions are misfolded proteins that accumulate within the brain in association with a rare group of fatal and infectious neurological disorders in humans and animals. A current challenge to research is a lack of in vitro model systems that are compatible with a wide range of prion strains, reproduce prion toxicity, and are amenable to genetic manipulations. In an attempt to address this need, here we produced stable cell lines that overexpress different versions of PrP^C through lentiviral transduction of immortalized human neural progenitor cells (ReN VM). Differentiated cultures made from the neural progenitor cell lines overexpressed PrP^C within 3D spheroid-like structures of TUBB3⁺ neurons and we observed evidence that PrP^C modulates formation of these structures, consistent with PrP^C’s role in neurogenesis. However, through repeated measurements of amyloid seeding activity in 6-week time course experiments, we failed to observe any evidence of prion replication within the differentiated ReN cultures following challenge with four prion isolates (human sCJD subtypes MM1 and VV2, and rodent adapted scrapie strains RML and 263K). We attributed amyloid seeding activity detected within the cultures to residual inoculum and concluded that PrP^C overexpression was insufficient to confer permissiveness of ReN cultures to prion infection. While our ReN cell prion infection model was unsuccessful, additional efforts to develop cellular models of human prion disease are highly warranted.

KEYWORDS:

• Creutzfeldt-Jakob disease
• human neural progenitor cells
• in vitro models
• neurogenesis
• prion disease
• prion models
• Scrapie

Acknowledgments

We wish to thank Dr. Gerold Schmitt-Ulms for critical review of the manuscript and for providing helpful comments. We also thank Jennifer Myskiw for assisting with the inoculum used in this study. Most of all, we thank CJD patients and families for providing the tissues that were used in this research.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19336896.2023.2206315.

Additional information

Funding

This work was funded by the Public Health Agency of Canada.