A single protective polymorphism in the prion protein blocks cross‐species prion replication in cultured cells

• Published in: Journal of neurochemistry Vol. 165; no. 2; pp. 230 - 245
• Main Authors: Arshad, Hamza, Patel, Zeel, Amano, Genki, Li, Le yao, Al‐Azzawi, Zaid A. M., Supattapone, Surachai, Schmitt‐Ulms, Gerold, Watts, Joel C.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.04.2023
• Subjects: Amino acids; Animals; Arvicolinae - genetics; Arvicolinae - metabolism; Cells, Cultured; Cricetinae; cultured cells; Glycosylation; Kuru; neurodegenerative diseases; Polymorphism; prion; Prion Diseases - genetics; Prion protein; Prion Proteins - genetics; Prion Proteins - metabolism; Prions; Prions - genetics; Prions - metabolism; protein misfolding; Proteins; Replication; cultured cells; neurodegenerative diseases; prion; protein misfolding
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/jnc.15739

The bank vole (BV) prion protein (PrP) can function as a universal acceptor of prions. However, the molecular details of BVPrP's promiscuity for replicating a diverse range of prion strains remain obscure. To develop a cultured cell paradigm capable of interrogating the unique properties of BVPrP, we generated monoclonal lines of CAD5 cells lacking endogenous PrP but stably expressing either hamster (Ha), mouse (Mo), or BVPrP (M109 or I109 polymorphic variants) and then challenged them with various strains of mouse or hamster prions. Cells expressing BVPrP were susceptible to both mouse and hamster prions, whereas cells expressing MoPrP or HaPrP could only be infected with species‐matched prions. Propagation of mouse and hamster prions in cells expressing BVPrP resulted in strain adaptation in several instances, as evidenced by alterations in conformational stability, glycosylation, susceptibility to anti‐prion small molecules, and the inability of BVPrP‐adapted mouse prion strains to infect cells expressing MoPrP. Interestingly, cells expressing BVPrP containing the G127V prion gene variant, identified in individuals resistant to kuru, were unable to become infected with prions. Moreover, the G127V polymorphic variant impeded the spontaneous aggregation of recombinant BVPrP. These results demonstrate that BVPrP can facilitate cross‐species prion replication in cultured cells and that a single amino acid change can override the prion‐permissive nature of BVPrP. This cellular paradigm will be useful for dissecting the molecular features of BVPrP that allow it to function as a universal prion acceptor. CAD5 cells lacking endogenous prion protein (PrP) expression (CAD5‐PrP−/−) were stably transfected with vectors encoding expression of wild‐type bank vole PrP or bank vole PrP containing the G127V substitution. Cells were challenged with either mouse or hamster prions and then passaged several times. Expression of bank vole PrP facilitated cross‐species prion infection, as revealed by the presence of proteinase K‐resistant PrP in cell lysates. In contrast, the addition of the protective G127V polymorphism to bank vole PrP completely blocked the ability of cells to become infected with mouse or hamster prions.