Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice

Several experimental evidences show that prions are non-conventional pathogens, which physical support consists only in proteins. This finding raised questions regarding the observed prion strain-to-strain variations and the species barrier that happened to be crossed with dramatic consequences on human health and veterinary policies during the last 3 decades. This review presents a focus on a few advances in the field of prion structure and prion strains characterization: from the historical approaches that allowed the concept of prion strains to emerge, to the last results demonstrating that a prion strain may in fact be a combination of a few quasi species with subtle biophysical specificities. Then, we will focus on the current knowledge on the factors that impact species barrier strength and species barrier crossing. Finally, we present probable scenarios on how the interaction of strain properties with host characteristics may account for differential selection of new conformer variants and eventually species barrier crossing.

Download Full-text

Increased Infectivity of Anchorless Mouse Scrapie Prions in Transgenic Mice Overexpressing Human Prion Protein

Journal of Virology ◽

10.1128/jvi.00362-15 ◽

2015 ◽

Vol 89 (11) ◽

pp. 6022-6032 ◽

Cited By ~ 11

Author(s):

Brent Race ◽

Katie Phillips ◽

Kimberly Meade-White ◽

James Striebel ◽

Bruce Chesebro

Keyword(s):

Amino Acid ◽

Amino Acid Sequence ◽

Transgenic Mice ◽

Prion Protein ◽

Prion Diseases ◽

Human Species ◽

Species Barrier ◽

Gpi Anchor ◽

Prion Infection ◽

Barrier Model

ABSTRACTPrion protein (PrP) is found in all mammals, mostly as a glycoprotein anchored to the plasma membrane by a C-terminal glycosylphosphatidylinositol (GPI) linkage. Following prion infection, host protease-sensitive prion protein (PrPsen or PrPC) is converted into an abnormal, disease-associated, protease-resistant form (PrPres). Biochemical characteristics, such as the PrP amino acid sequence, and posttranslational modifications, such as glycosylation and GPI anchoring, can affect the transmissibility of prions as well as the biochemical properties of the PrPres generated. Previousin vivostudies on the effects of GPI anchoring on prion infectivity have not examined cross-species transmission. In this study, we tested the effect of lack of GPI anchoring on a species barrier model using mice expressing human PrP. In this model, anchorless 22L prions derived from tg44 mice were more infectious than 22L prions derived from C57BL/10 mice when tested in tg66 transgenic mice, which expressed wild-type anchored human PrP at 8- to 16-fold above normal. Thus, the lack of the GPI anchor on the PrPres from tg44 mice appeared to reduce the effect of the mouse-human PrP species barrier. In contrast, neither source of prions induced disease in tgRM transgenic mice, which expressed human PrP at 2- to 4-fold above normal.IMPORTANCEPrion protein (PrP) is found in all mammals, usually attached to cells by an anchor molecule called GPI. Following prion infection, PrP is converted into a disease-associated form (PrPres). While most prion diseases are species specific, this finding is not consistent, and species barriers differ in strength. The amino acid sequence of PrP varies among species, and this variability affects prion species barriers. However, other PrP modifications, including glycosylation and GPI anchoring, may also influence cross-species infectivity. We studied the effect of PrP GPI anchoring using a mouse-to-human species barrier model. Experiments showed that prions produced by mice expressing only anchorless PrP were more infectious than prions produced in mice expressing anchored PrP. Thus, the lack of the GPI anchor on prions reduced the effect of the mouse-human species barrier. Our results suggest that prion diseases that produce higher levels of anchorless PrP may pose an increased risk for cross-species infection.

Download Full-text

Molecular and Transmission Characteristics of Primary-Passaged Ovine Scrapie Isolates in Conventional and Ovine PrP Transgenic Mice

Journal of Virology ◽

10.1128/jvi.01454-08 ◽

2008 ◽

Vol 82 (22) ◽

pp. 11197-11207 ◽

Cited By ~ 37

Author(s):

Alana M. Thackray ◽

Lee Hopkins ◽

John Spiropoulos ◽

Raymond Bujdoso

Keyword(s):

Transgenic Mice ◽

Transmission Characteristics ◽

Prion Strain ◽

Prion Strains ◽

True Diversity ◽

Incubation Periods ◽

Primary Transmission ◽

Molecular Nature ◽

Sheep Scrapie ◽

Mouse Lines

ABSTRACT A more complete assessment of ovine prion strain diversity will be achieved by complementing biological strain typing in conventional and ovine PrP transgenic mice with a biochemical analysis of the resultant PrPSc. This will provide a correlation between ovine prion strain phenotype and the molecular nature of different PrP conformers associated with particular prion strains. Here, we have compared the molecular and transmission characteristics of ovine ARQ/ARQ and VRQ/VRQ scrapie isolates following primary passage in tg338 (VRQ) and tg59 (ARQ) ovine PrP transgenic mice and the conventional mouse lines C57BL/6 (Prnp a ), RIII (Prnp a ), and VM (Prnp b ). Our data show that these different genotypes of scrapie isolates display similar incubation periods of >350 days in conventional and tg59 mice. Facilitated transmission of sheep scrapie isolates occurred in tg338 mice, with incubation times reduced to 64 days for VRQ/VRQ inocula and to ≤210 days for ARQ/ARQ samples. Distinct genotype-specific lesion profiles were seen in the brains of conventional and tg59 mice with prion disease, which was accompanied by the accumulation of more conformationally stable PrPSc, following inoculation with ARQ/ARQ compared to VRQ/VRQ scrapie isolates. In contrast, the lesion profiles, quantities, and stability of PrPSc induced by the same inocula in tg338 mice were more similar than in the other mouse lines. Our data show that primary transmission of different genotypes of ovine prions is associated with the formation of different conformers of PrPSc with distinct molecular properties and provide the basis of a molecular approach to identify the true diversity of ovine prion strains.

Download Full-text

PrPCGoverns Susceptibility to Prion Strains in Bank Vole, While Other Host Factors Modulate Strain Features

Journal of Virology ◽

10.1128/jvi.01592-16 ◽

2016 ◽

Vol 90 (23) ◽

pp. 10660-10669 ◽

Cited By ~ 20

Author(s):

J. C. Espinosa ◽

R. Nonno ◽

M. Di Bari ◽

P. Aguilar-Calvo ◽

L. Pirisinu ◽

...

Keyword(s):

Mouse Model ◽

Transgenic Mice ◽

Transgenic Mouse ◽

Bank Vole ◽

Differential Susceptibility ◽

Transgenic Mouse Model ◽

Host Factors ◽

Bank Voles ◽

Prion Strains ◽

Species Specific

ABSTRACTBank vole is a rodent species that shows differential susceptibility to the experimental transmission of different prion strains. In this work, the transmission features of a panel of diverse prions with distinct origins were assayed both in bank vole expressing methionine at codon 109 (Bv109M) and in transgenic mice expressing physiological levels of bank vole PrPC(the BvPrP-Tg407 mouse line). This work is the first systematic comparison of the transmission features of a collection of prion isolates, representing a panel of diverse prion strains, in a transgenic-mouse model and in its natural counterpart. The results showed very similar transmission properties in both the natural species and the transgenic-mouse model, demonstrating the key role of the PrP amino acid sequence in prion transmission susceptibility. However, differences in the PrPSctypes propagated by Bv109M and BvPrP-Tg407 suggest that host factors other than PrPCmodulate prion strain features.IMPORTANCEThe differential susceptibility of bank voles to prion strains can be modeled in transgenic mice, suggesting that this selective susceptibility is controlled by the vole PrP sequence alone rather than by other species-specific factors. Differences in the phenotypes observed after prion transmissions in bank voles and in the transgenic mice suggest that host factors other than the PrPCsequence may affect the selection of the substrain replicating in the animal model.

Download Full-text

Prion Strains and Neuromuscular Disease in PrP Transgenic Mice

Bovine Spongiform Encephalopathy ◽

10.1007/978-1-4612-2406-8_15 ◽

1996 ◽

pp. 192-201

Author(s):

George A. Carlson

Keyword(s):

Transgenic Mice ◽

Neuromuscular Disease ◽

Prion Strains

Download Full-text

Isolation of Novel Synthetic Prion Strains by Amplification in Transgenic Mice Coexpressing Wild-Type and Anchorless Prion Proteins

Journal of Virology ◽

10.1128/jvi.01353-12 ◽

2012 ◽

Vol 86 (21) ◽

pp. 11763-11778 ◽

Cited By ~ 29

Author(s):

G. J. Raymond ◽

B. Race ◽

J. R. Hollister ◽

D. K. Offerdahl ◽

R. A. Moore ◽

...

Keyword(s):

Transgenic Mice ◽

Prion Proteins ◽

Wild Type ◽

Prion Strains

Download Full-text

Strain Fidelity of Chronic Wasting Disease upon Murine Adaptation

Journal of Virology ◽

10.1128/jvi.01120-06 ◽

2006 ◽

Vol 80 (24) ◽

pp. 12303-12311 ◽

Cited By ~ 57

Author(s):

Christina J. Sigurdson ◽

Giuseppe Manco ◽

Petra Schwarz ◽

Pawel Liberski ◽

Edward A. Hoover ◽

...

Keyword(s):

North America ◽

Transgenic Mice ◽

Chronic Wasting Disease ◽

Amyloid Plaques ◽

Serial Passage ◽

Host Factors ◽

Species Barrier ◽

Wasting Disease ◽

Cerebral Amyloid ◽

Efficient Transmission

ABSTRACT Chronic wasting disease (CWD), a prion disease of deer and elk, is highly prevalent in some regions of North America. The establishment of mouse-adapted CWD prions has proven difficult due to the strong species barrier between mice and deer. Here we report the efficient transmission of CWD to transgenic mice overexpressing murine PrP. All mice developed disease 500 ± 62 days after intracerebral CWD challenge. The incubation period decreased to 228 ± 103 days on secondary passage and to 162 ± 6 days on tertiary passage. Mice developed very large, radially structured cerebral amyloid plaques similar to those of CWD-infected deer and elk. PrPSc was detected in spleen, indicating that murine CWD was lymphotropic. PrPSc glycoform profiles maintained a predominantly diglycosylated PrP pattern, as seen with CWD in deer and elk, across all passages. Therefore, all pathological, biochemical, and histological strain characteristics of CWD appear to persist upon repetitive serial passage through mice. These findings indicate that the salient strain-specific properties of CWD are encoded by agent-intrinsic components rather than by host factors.

Download Full-text

In vivo evasion of MxA by avian influenza viruses requires human signature in the viral nucleoprotein

Journal of Experimental Medicine ◽

10.1084/jem.20161033 ◽

2017 ◽

Vol 214 (5) ◽

pp. 1239-1248 ◽

Cited By ~ 28

Author(s):

Christoph M. Deeg ◽

Ebrahim Hassan ◽

Pascal Mutz ◽

Lara Rheinemann ◽

Veronika Götz ◽

...

Keyword(s):

Avian Influenza ◽

Transgenic Mice ◽

Influenza A ◽

Influenza Viruses ◽

Influenza A Viruses ◽

Avian Influenza Viruses ◽

Species Barrier ◽

Human Virus ◽

Adaptive Mutations

Zoonotic transmission of influenza A viruses can give rise to devastating pandemics, but currently it is impossible to predict the pandemic potential of circulating avian influenza viruses. Here, we describe a new mouse model suitable for such risk assessment, based on the observation that the innate restriction factor MxA represents an effective species barrier that must be overcome by zoonotic viruses. Our mouse lacks functional endogenous Mx genes but instead carries the human MX1 locus as a transgene. Such transgenic mice were largely resistant to highly pathogenic avian H5 and H7 influenza A viruses, but were almost as susceptible to infection with influenza viruses of human origin as nontransgenic littermates. Influenza A viruses that successfully established stable lineages in humans have acquired adaptive mutations which allow partial MxA escape. Accordingly, an engineered avian H7N7 influenza virus carrying a nucleoprotein with signature mutations typically found in human virus isolates was more virulent in transgenic mice than parental virus, demonstrating that a few amino acid changes in the viral target protein can mediate escape from MxA restriction in vivo. Similar mutations probably need to be acquired by emerging influenza A viruses before they can spread in the human population.

Download Full-text

Host Determinants of Prion Strain Diversity Independent of Prion Protein Genotype

Journal of Virology ◽

10.1128/jvi.01586-15 ◽

2015 ◽

Vol 89 (20) ◽

pp. 10427-10441 ◽

Cited By ~ 23

Author(s):

Jenna Crowell ◽

Andrew Hughson ◽

Byron Caughey ◽

Richard A. Bessen

Keyword(s):

Transgenic Mice ◽

Prion Protein ◽

Protein Gene ◽

Phenotypic Diversity ◽

Prion Diseases ◽

Conformational Stability ◽

Epigenetic Mechanism ◽

Prion Strain ◽

Disease Phenotypes ◽

Prion Strains

ABSTRACTPhenotypic diversity in prion diseases can be specified by prion strains in which biological traits are propagated through an epigenetic mechanism mediated by distinct PrPScconformations. We investigated the role of host-dependent factors on phenotypic diversity of chronic wasting disease (CWD) in different host species that express the same prion protein gene (Prnp). Two CWD strains that have distinct biological, biochemical, and pathological features were identified in transgenic mice that express the Syrian golden hamster (SGH)Prnp. The CKY strain of CWD had a shorter incubation period than the WST strain of CWD, but after transmission to SGH, the incubation period of CKY CWD was ∼150 days longer than WST CWD. Limited proteinase K digestion revealed strain-specific PrPScpolypeptide patterns that were maintained in both hosts, but the solubility and conformational stability of PrPScdiffered for the CWD strains in a host-dependent manner. WST CWD produced PrPScamyloid plaques in the brain of the SGH that were partially insoluble and stable at a high concentration of protein denaturant. However, in transgenic mice, PrPScfrom WST CWD did not assemble into plaques, was highly soluble, and had low conformational stability. Similar studies using the HY and DY strains of transmissible mink encephalopathy resulted in minor differences in prion biological and PrPScproperties between transgenic mice and SGH. These findings indicate that host-specific pathways that are independent ofPrnpcan alter the PrPScconformation of certain prion strains, leading to changes in the biophysical properties of PrPSc, neuropathology, and clinical prion disease.IMPORTANCEPrions are misfolded pathogenic proteins that cause neurodegeneration in humans and animals. Transmissible prion diseases exhibit a spectrum of disease phenotypes and the basis of this diversity is encoded in the structure of the pathogenic prion protein and propagated by an epigenetic mechanism. In the present study, we investigated prion diversity in two hosts species that express the same prion protein gene. While prior reports have demonstrated that prion strain properties are stable upon infection of the same host species and prion protein genotype, our findings indicate that certain prion strains can undergo dramatic changes in biological properties that are not dependent on the prion protein. Therefore, host factors independent of the prion protein can affect prion diversity. Understanding how host pathways can modify prion disease phenotypes may provide clues on how to alter prion formation and lead to treatments for prion, and other, human neurodegenerative diseases of protein misfolding.

Download Full-text

Generation of human chronic wasting disease in transgenic mice

Acta Neuropathologica Communications ◽

10.1186/s40478-021-01262-y ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Zerui Wang ◽

Kefeng Qin ◽

Manuel V. Camacho ◽

Ignazio Cali ◽

Jue Yuan ◽

...

Keyword(s):

Transgenic Mice ◽

Prion Disease ◽

Protein Misfolding ◽

Chronic Wasting Disease ◽

Cellular Prion Protein ◽

Spongiform Encephalopathy ◽

Species Barrier ◽

Wasting Disease ◽

Bona Fide

AbstractChronic wasting disease (CWD) is a cervid prion disease caused by the accumulation of an infectious misfolded conformer (PrPSc) of cellular prion protein (PrPC). It has been spreading rapidly in North America and also found in Asia and Europe. Although bovine spongiform encephalopathy (i.e. mad cow disease) is the only animal prion disease known to be zoonotic, the transmissibility of CWD to humans remains uncertain. Here we report the generation of the first CWD-derived infectious human PrPSc by elk CWD PrPSc-seeded conversion of PrPC in normal human brain homogenates using in vitro protein misfolding cyclic amplification (PMCA). Western blotting with human PrP selective antibody confirmed that the PMCA-generated protease-resistant PrPSc was derived from the human PrPC substrate. Two lines of humanized transgenic mice expressing human PrP with either Val or Met at the polymorphic codon 129 developed clinical prion disease following intracerebral inoculation with the PMCA-generated CWD-derived human PrPSc. Diseased mice exhibited distinct PrPSc patterns and neuropathological changes in the brain. Our study, using PMCA and animal bioassays, provides the first evidence that CWD PrPSc can cross the species barrier to convert human PrPC into infectious PrPSc that can produce bona fide prion disease when inoculated into humanized transgenic mice.

Download Full-text