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Otero A, Velásquez CD, Aiken J, McKenzie D. Chronic wasting disease: a cervid prion infection looming to spillover. Vet Res 2021; 52:115. [PMID: 34488900 PMCID: PMC8420063 DOI: 10.1186/s13567-021-00986-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/29/2021] [Indexed: 11/10/2022] Open
Abstract
The spread of chronic wasting disease (CWD) during the last six decades has resulted in cervid populations of North America where CWD has become enzootic. This insidious disease has also been reported in wild and captive cervids from other continents, threatening ecosystems, livestock and public health. These CWD "hot zones" are particularly complex given the interplay between cervid PRNP genetics, the infection biology, the strain diversity of infectious prions and the long-term environmental persistence of infectivity, which hinder eradication efforts. Here, we review different aspects of CWD including transmission mechanisms, pathogenesis, epidemiology and assessment of interspecies infection. Further understanding of these aspects could help identify "control points" that could help reduce exposure for humans and livestock and decrease CWD spread between cervids.
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Affiliation(s)
- Alicia Otero
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada.,Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, Universidad de Zaragoza, Zaragoza, Spain
| | - Camilo Duque Velásquez
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Judd Aiken
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada.,Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada
| | - Debbie McKenzie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada. .,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada.
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Beekes M. The Neural Gut-Brain Axis of Pathological Protein Aggregation in Parkinson's Disease and Its Counterpart in Peroral Prion Infections. Viruses 2021; 13:1394. [PMID: 34372600 PMCID: PMC8310171 DOI: 10.3390/v13071394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 12/17/2022] Open
Abstract
A neuropathological hallmark of Parkinson's disease (PD) is the cerebral deposition of abnormally aggregated α-synuclein (αSyn). PD-associated αSyn (αSynPD) aggregates are assumed to act, in a prion-like manner, as proteinaceous nuclei ("seeds") capable of self-templated propagation. Braak and colleagues put forward the idea of a neural gut-brain axis mediating the centripetal spread of αSynPD pathology from the enteric nervous system (ENS) to the brain in PD. This has sparked great interest and initiated passionate discussions both in support of and opposing the suggested hypothesis. A precedent for the spread of protein seeds or seeding from the gastro-intestinal (GI) tract to the central nervous system (CNS) had been previously revealed for pathological prion protein in peroral prion infections. This article scrutinizes the similarities and dissimilarities between the pathophysiological spread of disease-associated protein aggregation along the neural gut-brain axis in peroral prion infections and PD. On this basis, evidence supporting the proposed neural gut-brain axis in PD is concluded to be not as robust as that established for peroral prion infections. New tools for the ultrasensitive detection of αSynPD-associated seeding activity in archived or fresh human tissue samples such as real-time quaking induced conversion (RT-QuIC) or protein misfolding cyclic amplification (PMCA) assays can possibly help to address this deficit in the future.
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Affiliation(s)
- Michael Beekes
- Prion and Prionoid Research Unit, ZBS 6-Proteomics and Spectroscopy, ZBS-Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany
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Ashok A, Karmakar S, Chandel R, Ravikumar R, Dalal S, Kong Q, Singh N. Prion protein modulates iron transport in the anterior segment: Implications for ocular iron homeostasis and prion transmission. Exp Eye Res 2018; 175:1-13. [PMID: 29859760 PMCID: PMC6167182 DOI: 10.1016/j.exer.2018.05.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/17/2018] [Accepted: 05/30/2018] [Indexed: 12/14/2022]
Abstract
Iron is an essential biometal in the aqueous humor, the principal source of nutrients for the avascular cornea and the lens. Here, we explored whether the ciliary body (CB), the source of aqueous humor, transports iron, and if the prion protein (PrPC) facilitates this process as in the outer retina. Using a combination of human, bovine, and mouse eyes as models, we report the expression of iron export proteins ferroportin and ceruloplasmin, and major iron uptake and storage proteins transferrin, transferrin receptor, and ferritin in the ciliary epithelium, indicating active exchange of iron at this site. Ferroportin and transferrin receptor are also expressed in the corneal endothelium. However, the relative expression of iron export and uptake proteins suggests export from the ciliary epithelium and import by corneal endothelium. In addition, abundant expression of PrPC, a ferrireductase that facilitates iron transport, is noted in pigmented and non-pigmented epithelium of the CB, posterior pigmented epithelium of the iris, corneal endothelium and epithelium, and lens epithelium. Notably, majority of PrPC in the ciliary epithelium is cleaved at the β-site as in retinal pigment epithelial cells, suggesting a role in iron transport. Most of the PrPC in the cornea, however, is full-length, and susceptible to aggregation by intracerebrally inoculated PrP-scrapie, an infectious conformation of PrPC responsible for human and animal prion disorders. Soluble PrPC is present in the aqueous and vitreous humor, a provocative observation with significant implications. Together, these observations suggest independent cycling of iron in the anterior segment, and a prominent role of PrPC in this process. Aggregation of PrPC in the cornea of PrP-scrapie-infected animals raises the alarming possibility of transmission of animal prions through corneal abrasions.
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Affiliation(s)
- Ajay Ashok
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Shilpita Karmakar
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Rajeev Chandel
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Ranjana Ravikumar
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Stuti Dalal
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Qingzhong Kong
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.
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Jeffrey M, Witz JP, Martin S, Hawkins SAC, Bellworthy SJ, Dexter GE, Thurston L, González L. Dynamics of the natural transmission of bovine spongiform encephalopathy within an intensively managed sheep flock. Vet Res 2015; 46:126. [PMID: 26511838 PMCID: PMC4625529 DOI: 10.1186/s13567-015-0269-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/09/2015] [Indexed: 11/29/2022] Open
Abstract
Sheep are susceptible to the bovine spongiform encephalopathy (BSE) agent and in the UK they may have been exposed to BSE via contaminated meat and bone meal. An experimental sheep flock was established to determine whether ovine BSE could be naturally transmitted under conditions of intensive husbandry. The flock consisted of 113 sheep of different breeds and susceptible PRNP genotypes orally dosed with BSE, 159 sheep subsequently born to them and 125 unchallenged sentinel controls. BSE was confirmed in 104 (92%) orally dosed sheep and natural transmission was recorded for 14 of 79 (18%) lambs born to BSE infected dams, with rates varying according to PRNP genotype. The likelihood of natural BSE transmission was linked to stage of incubation period of the dam: the attack rate for lambs born within 100 days of the death of BSE infected dams was significantly higher (9/22, 41%) than for the rest (5/57, 9%). Within the group of ewes lambing close to death, those rearing infected progeny (n = 8, for 9/12 infected lambs) showed a significantly greater involvement of lymphoid tissues than those rearing non-infected offspring (n = 8, for 0/10 infected lambs). Horizontal transmission to the progeny of non-infected mothers was recorded only once (1/205, 0.5%). This low rate of lateral transmission was attributed, at least partly, to an almost complete absence of infected placentas. We conclude that, although BSE can be naturally transmitted through dam-lamb close contact, the infection in this study flock would not have persisted due to low-efficiency maternal and lateral transmissions.
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Affiliation(s)
- Martin Jeffrey
- Animal and Plant Health Agency (APHA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK.
| | - Janey P Witz
- Animal and Plant Health Agency (APHA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK.
| | - Stuart Martin
- Animal and Plant Health Agency (APHA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK.
| | | | | | | | - Lisa Thurston
- APHA-Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK.
| | - Lorenzo González
- Animal and Plant Health Agency (APHA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK.
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Wang X, McGovern G, Zhang Y, Wang F, Zha L, Jeffrey M, Ma J. Intraperitoneal Infection of Wild-Type Mice with Synthetically Generated Mammalian Prion. PLoS Pathog 2015; 11:e1004958. [PMID: 26136122 PMCID: PMC4489884 DOI: 10.1371/journal.ppat.1004958] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 05/14/2015] [Indexed: 11/23/2022] Open
Abstract
The prion hypothesis postulates that the infectious agent in transmissible spongiform encephalopathies (TSEs) is an unorthodox protein conformation based agent. Recent successes in generating mammalian prions in vitro with bacterially expressed recombinant prion protein provide strong support for the hypothesis. However, whether the pathogenic properties of synthetically generated prion (rec-Prion) recapitulate those of naturally occurring prions remains unresolved. Using end-point titration assay, we showed that the in vitro prepared rec-Prions have infectious titers of around 104 LD50 / μg. In addition, intraperitoneal (i.p.) inoculation of wild-type mice with rec-Prion caused prion disease with an average survival time of 210 – 220 days post inoculation. Detailed pathological analyses revealed that the nature of rec-Prion induced lesions, including spongiform change, disease specific prion protein accumulation (PrP-d) and the PrP-d dissemination amongst lymphoid and peripheral nervous system tissues, the route and mechanisms of neuroinvasion were all typical of classical rodent prions. Our results revealed that, similar to naturally occurring prions, the rec-Prion has a titratable infectivity and is capable of causing prion disease via routes other than direct intra-cerebral challenge. More importantly, our results established that the rec-Prion caused disease is pathogenically and pathologically identical to naturally occurring contagious TSEs, supporting the concept that a conformationally altered protein agent is responsible for the infectivity in TSEs. The transmissible spongiform encephalopathies (TSEs) are a group of infectious neurodegenerative diseases affecting both humans and animals. The prion hypothesis postulates that prions are protein conformation based infectious agents responsible for TSE infectivity. Prions have been synthetically generated in vitro, but it remains unclear whether the properties of synthetically generated prion are the same as those of TSE agents and whether the disease caused by synthetically generated prion is identical to naturally occurring TSEs. In this study, we demonstrated that similar to the classical TSE agents, the synthetically generated prion has a titratable infectivity and is able to cause prion disease in wild-type mice via routes other than direct intra-cerebral inoculation. More importantly, we showed that the synthetically generated prion induced pathological changes, including the dissemination of disease-specific prion protein accumulation and the route and mechanism of neuroinvasion, were all typical of classical TSEs. These results demonstrate the similarity of synthetically generated prion to the infectious agent in TSEs, providing strong evidence supporting the prion hypothesis.
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Affiliation(s)
- Xinhe Wang
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, Ohio, United States of America
| | - Gillian McGovern
- Animal and Plant Health Agency, Lasswade Laboratory, Pentlands Science Park, Penicuik, Midlothian, Scotland
| | - Yi Zhang
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, Ohio, United States of America
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, Shanghai, China
| | - Fei Wang
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, Ohio, United States of America
| | - Liang Zha
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, Ohio, United States of America
| | - Martin Jeffrey
- Animal and Plant Health Agency, Lasswade Laboratory, Pentlands Science Park, Penicuik, Midlothian, Scotland
| | - Jiyan Ma
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, Ohio, United States of America
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, Shanghai, China
- * E-mail:
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McGovern G, Martin S, Jeffrey M, Bellworthy SJ, Spiropoulos J, Green R, Lockey R, Vickery CM, Thurston L, Dexter G, Hawkins SAC, González L. Influence of breed and genotype on the onset and distribution of infectivity and disease-associated prion protein in sheep following oral infection with the bovine spongiform encephalopathy agent. J Comp Pathol 2014; 152:28-40. [PMID: 25435510 DOI: 10.1016/j.jcpa.2014.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 08/29/2014] [Accepted: 09/30/2014] [Indexed: 11/20/2022]
Abstract
The onset and distribution of infectivity and disease-specific prion protein (PrP(d)) accumulation was studied in Romney and Suffolk sheep of the ARQ/ARQ, ARQ/ARR and ARR/ARR prion protein gene (Prnp) genotypes (where A stands for alanine, R for arginine and Q for glutamine at codons 136, 154 and 171 of PrP), following experimental oral infection with cattle-derived bovine spongiform encephalopathy (BSE) agent. Groups of sheep were killed at regular intervals and a wide range of tissues taken for mouse bioassay or immunohistochemistry (IHC), or both. Bioassay results for infectivity were mostly coincident with those of PrP(d) detection by IHC both in terms of tissues and time post infection. Neither PrP(d) nor infectivity was detected in any tissues of BSE-dosed ARQ/ARR or ARR/ARR sheep or of undosed controls. Moreover, four ARQ/ARQ Suffolk sheep, which were methionine (M)/threonine heterozygous at codon 112 of the Prnp gene, did not show any biological or immunohistochemical evidence of infection, while those homozygous for methionine (MARQ/MARQ) did. In MARQ/MARQ sheep of both breeds, initial PrP(d) accumulation was identified in lymphoreticular system (LRS) tissues followed by the central nervous system (CNS) and enteric nervous system (ENS) and finally by the autonomic nervous system and peripheral nervous system and other organs. Detection of infectivity closely mimicked this sequence. No PrP(d) was observed in the ENS prior to its accumulation in the CNS, suggesting that ENS involvement occurred simultaneously to that of, or followed centrifugal spread from, the CNS. The distribution of PrP(d) within the ENS further suggested a progressive spread from the ileal plexus to other ENS segments via neuronal connections of the gut wall. Differences between the two breeds were noted in terms of involvement of LRS and ENS tissues, with Romney sheep showing a more delayed and less consistent PrP(d) accumulation than Suffolk sheep in such tissues. Whether this accounted for the slight delay (∼5 months) in the appearance of clinical signs in Romney sheep is debatable since by the last scheduled kill before animals reached clinical end point, both breeds showed widespread accumulation and similar magnitudes of PrP(d) accumulation in the brain.
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Affiliation(s)
- G McGovern
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Penicuik, Midlothian, UK.
| | - S Martin
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Penicuik, Midlothian, UK
| | - M Jeffrey
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Penicuik, Midlothian, UK
| | - S J Bellworthy
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Addlestone, Surrey, UK
| | - J Spiropoulos
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Addlestone, Surrey, UK
| | - R Green
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Addlestone, Surrey, UK
| | - R Lockey
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Addlestone, Surrey, UK
| | - C M Vickery
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Addlestone, Surrey, UK
| | - L Thurston
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Addlestone, Surrey, UK
| | - G Dexter
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Addlestone, Surrey, UK
| | - S A C Hawkins
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Addlestone, Surrey, UK
| | - L González
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Penicuik, Midlothian, UK
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Scientific Opinion on the scrapie situation in the EU after 10 years of monitoring and control in sheep and goats. EFSA J 2014. [DOI: 10.2903/j.efsa.2014.3781] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Jeffrey M, Martin S, Chianini F, Eaton S, Dagleish MP, González L. Incidence of infection in Prnp ARR/ARR sheep following experimental inoculation with or natural exposure to classical scrapie. PLoS One 2014; 9:e91026. [PMID: 24614120 PMCID: PMC3948952 DOI: 10.1371/journal.pone.0091026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 02/06/2014] [Indexed: 12/02/2022] Open
Abstract
The prion protein gene (Prnp) is highly influential in determining risk and susceptibility of sheep exposed to classical scrapie. Sheep homozygous for alanine at codon 136 and arginine at codons 154 and 171 (ARR/ARR) of the Prnp gene are historically considered to be highly resistant to classical scrapie, although they form a significant fraction of cases of atypical scrapie. To date, experimental transmission of prions to ARR/ARR sheep has only been achieved with the BSE agent and mostly by the intracerebral route. We summarise here the results of six separate studies, in which 95 sheep of the ARR/ARR genotype were naturally exposed to (n = 18) or experimentally challenged with (n = 77) natural or experimental sources of classical scrapie by the oral, intra-intestinal, subcutaneous or intracerebral routes and allowed to survive for periods of up to 94 months post-infection. Only the intracerebral route resulted in disease and/or amplification of disease associated PrP (PrPd), and only in two of 19 sheep that survived for longer than 36 months. Discriminatory immunohistochemistry and Western blot confirmed the scrapie, non-BSE signature of PrPd in those two sheep. However, the neuropathological phenotype was different from any other scrapie (classical or atypical) or BSE source previously reported in sheep of any Prnp genotype. These studies confirm the widely held view that ARR/ARR sheep are highly resistant to classical scrapie infection, at least within their commercial lifespan. Moreover, within the constraints of the present studies (only two infected sheep), these results do not support the suggestion that atypical scrapie or BSE are generated by adaptation or mutation of classical scrapie in sheep of resistant ARR/ARR genotype.
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Affiliation(s)
- Martin Jeffrey
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland, United Kingdom
- * E-mail:
| | - Stuart Martin
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland, United Kingdom
| | - Francesca Chianini
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland, United Kingdom
| | - Samantha Eaton
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland, United Kingdom
| | - Mark P. Dagleish
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland, United Kingdom
| | - Lorenzo González
- Animal Health and Veterinary Laboratories Agency (AHVLA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland, United Kingdom
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