Agrimi U, Nonno R, Dell'Omo G, Di Bari MA, Conte M, Chiappini B, Esposito E, Di Guardo G, Windl O, Vaccari G, Lipp HP. Prion protein amino acid determinants of differential susceptibility and molecular feature of prion strains in mice and voles.
PLoS Pathog 2008;
4:e1000113. [PMID:
18654630 PMCID:
PMC2453331 DOI:
10.1371/journal.ppat.1000113]
[Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Accepted: 06/30/2008] [Indexed: 01/05/2023] Open
Abstract
The bank vole is a rodent susceptible to different prion strains from humans and various animal species. We analyzed the transmission features of different prions in a panel of seven rodent species which showed various degrees of phylogenetic affinity and specific prion protein (PrP) sequence divergences in order to investigate the basis of vole susceptibility in comparison to other rodent models. At first, we found a differential susceptibility of bank and field voles compared to C57Bl/6 and wood mice. Voles showed high susceptibility to sheep scrapie but were resistant to bovine spongiform encephalopathy, whereas C57Bl/6 and wood mice displayed opposite features. Infection with mouse-adapted scrapie 139A was faster in voles than in C57Bl/6 and wood mice. Moreover, a glycoprofile change was observed in voles, which was reverted upon back passage to mice. All strains replicated much faster in voles than in mice after adapting to the new species. PrP sequence comparison indicated a correlation between the transmission patterns and amino acids at positions 154 and 169 (Y and S in mice, N and N in voles). This correlation was confirmed when inoculating three additional rodent species: gerbils, spiny mice and oldfield mice with sheep scrapie and 139A. These rodents were chosen because oldfield mice do have the 154N and 169N substitutions, whereas gerbil and spiny mice do not have them. Our results suggest that PrP residues 154 and 169 drive the susceptibility, molecular phenotype and replication rate of prion strains in rodents. This might have implications for the assessment of host range and molecular traceability of prion strains, as well as for the development of improved animal models for prion diseases.
Prions are unconventional infectious agents that cause fatal neurodegenerative diseases in animals and humans. A pathological form of the cellular prion protein (PrPC), named PrPSc, appears to be the major or the sole component of prions. These agents are transmitted by inducing the conversion of host PrPC into PrPSc that accumulates in the brain of affected individuals. Different factors are believed to modulate such events, which explains the variable transmission efficiency observed under inter-species experimental inoculation. These factors are still fairly unknown, although evidence exists that some kind of structural compatibility between PrPSc of the infectious inoculum and PrPC of the host has a role in making transmission more or less efficient. We investigated the transmission of prions to different rodents and showed that specific amino acid substitutions (Y154N and S169N) in the prion protein are major determinants of susceptibility to prions. In particular, we showed that these specific variations i) direct the transmission rate of prions between different species in a way that is dependent on the prion strain, ii) affect the molecular characteristics of prions, and iii) influence their replication efficiency.
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