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Pirisinu L, Di Bari MA, D’Agostino C, Vanni I, Riccardi G, Marcon S, Vaccari G, Chiappini B, Benestad SL, Agrimi U, Nonno R. A single amino acid residue in bank vole prion protein drives permissiveness to Nor98/atypical scrapie and the emergence of multiple strain variants. PLoS Pathog 2022; 18:e1010646. [PMID: 35731839 PMCID: PMC9255773 DOI: 10.1371/journal.ppat.1010646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/05/2022] [Accepted: 06/03/2022] [Indexed: 12/03/2022] Open
Abstract
Prions are infectious agents that replicate through the autocatalytic misfolding of the cellular prion protein (PrPC) into infectious aggregates (PrPSc) causing fatal neurodegenerative diseases in humans and animals. Prions exist as strains, which are encoded by conformational variants of PrPSc. The transmissibility of prions depends on the PrPC sequence of the recipient host and on the incoming prion strain, so that some animal prion strains are more contagious than others or are transmissible to new species, including humans. Nor98/atypical scrapie (AS) is a prion disease of sheep and goats reported in several countries worldwide. At variance with classical scrapie (CS), AS is considered poorly contagious and is supposed to be spontaneous in origin. The zoonotic potential of AS, its strain variability and the relationships with the more contagious CS strains remain largely unknown. We characterized AS isolates from sheep and goats by transmission in ovinised transgenic mice (tg338) and in two genetic lines of bank voles, carrying either methionine (BvM) or isoleucine (BvI) at PrP residue 109. All AS isolates induced the same pathological phenotype in tg338 mice, thus proving that they encoded the same strain, irrespective of their geographical origin or source species. In bank voles, we found that the M109I polymorphism dictates the susceptibility to AS. BvI were susceptible and faithfully reproduced the AS strain, while the transmission in BvM was highly inefficient and was characterized by a conformational change towards a CS-like prion strain. Sub-passaging experiments revealed that the main strain component of AS is accompanied by minor CS-like strain components, which can be positively selected during replication in both AS-resistant or AS-susceptible animals. These findings add new clues for a better comprehension of strain selection dynamics in prion infections and have wider implications for understanding the origin of contagious prion strains, such as CS. Prions are transmissible agents responsible for fatal neurodegenerative diseases in humans and animals. Prions exist as strains, exhibiting distinct disease phenotypes and transmission properties. Some prion diseases occur sporadically with a supposedly spontaneous origin, while others are contagious and give rise to epidemics, mainly in animals. We investigated the strain properties of Nor98/atypical scrapie (AS), a sporadic prion disease of small ruminants. We found that AS was faithfully reproduced not only in a homologous context, i.e. ovinised transgenic mice, but also in an unrelated animal species, the bank vole. A natural polymorphism of the bank vole prion protein, coding for methionine (BvM) or for isoleucine (BvI) at codon 109, dictated the susceptibility of voles to AS, with BvI being highly susceptible to AS and BvM rather resistant. Most importantly, the M109I polymorphism mediated the emergence of AS-derived mutant prion strains resembling classical scrapie (CS), a contagious prion disease. Finally, by sub-passages in bank voles, we found that the main strain component of AS is accompanied by minor CS-like strain components, which can be positively selected during replication in both AS-resistant or AS-susceptible vole lines. These findings allow a better understanding of strain selection dynamics and suggest a link between sporadic and contagious prion diseases.
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Affiliation(s)
- Laura Pirisinu
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Michele Angelo Di Bari
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Claudia D’Agostino
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Ilaria Vanni
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Geraldina Riccardi
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Stefano Marcon
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Gabriele Vaccari
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Barbara Chiappini
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | | | - Umberto Agrimi
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Romolo Nonno
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
- * E-mail:
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Piel RB, McElliott VR, Stanton JB, Zhuang D, Madsen-Bouterse SA, Hamburg LK, Harrington RD, Schneider DA. PrPres in placental tissue following experimental transmission of atypical scrapie in ARR/ARR sheep is not infectious by Tg338 mouse bioassay. PLoS One 2022; 17:e0262766. [PMID: 35061802 PMCID: PMC8782414 DOI: 10.1371/journal.pone.0262766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/04/2022] [Indexed: 11/19/2022] Open
Abstract
Nor98-like atypical scrapie is a sporadic disease that affects the central nervous system of sheep and goats that, in contrast to classical scrapie, is not generally regarded as naturally transmissible. However, infectivity has been demonstrated via bioassay not only of brain tissue but also of certain peripheral nerves, lymphoid tissues, and muscle. This study examines placental tissue, a well characterized route of natural transmission for classical scrapie. Further, this study was conducted in sheep homozygous for the classical scrapie resistant ARR genotype and is the first to characterize the transmission of Nor98-like scrapie between homozygous-ARR sheep. Nor98-like scrapie isolated from a United States ARR/ARR sheep was transmitted to four ARR/ARR ewes via intracerebral inoculation of brain homogenate. These ewes were followed and observed to 8 years of age, remained non-clinical but exhibited progression of infection that was consistent with Nor98-like scrapie, including characteristic patterns of PrPSc accumulation in the brain and a lack of accumulation in peripheral lymphoid tissues as detected by conventional methods. Immunoblots of placental tissues from the infected ewes revealed accumulation of a distinct conformation of PrPres, particularly as the animals aged; however, the placenta showed no infectivity when analyzed via ovinized mouse bioassay. Taken together, these results support a low risk for natural transmission of Nor98-like scrapie in ARR/ARR sheep.
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Affiliation(s)
- Robert B. Piel
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, Washington, United States of America
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Valerie R. McElliott
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - James B. Stanton
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Dongyue Zhuang
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, Washington, United States of America
| | - Sally A. Madsen-Bouterse
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Linda K. Hamburg
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, Washington, United States of America
| | - Robert D. Harrington
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, Washington, United States of America
- Department of Comparative Medicine, University of Washington, Seattle, Washington, United States of America
| | - David A. Schneider
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, Washington, United States of America
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- * E-mail:
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Abstract
In sheep, scrapie is a fatal neurologic disease that is caused by a misfolded protein called a prion (designated PrPSc). The normal cellular prion protein (PrPC) is encoded by an endogenous gene, PRNP, that is present in high concentrations within the CNS. Although a broad range of functions has been described for PrPC, its entire range of functions has yet to be fully elucidated. Accumulation of PrPSc results in neurodegeneration. The PRNP gene has several naturally occurring polymorphisms, and there is a strong correlation between scrapie susceptibility and PRNP genotype. The cornerstone of scrapie eradication programs is the selection of scrapie-resistant genotypes to eliminate classical scrapie. Transmission of classical scrapie in sheep occurs during the prenatal and periparturient periods when lambs are highly susceptible. Initially, the scrapie agent is disseminated throughout the lymphoid system and into the CNS. Shedding of the scrapie agent occurs before the onset of clinical signs. In contrast to classical scrapie, atypical scrapie is believed to be a spontaneous disease that occurs in isolated instances in older animals within a flock. The agent that causes atypical scrapie is not considered to be naturally transmissible. Transmission of the scrapie agent to species other than sheep, including deer, has been experimentally demonstrated as has the transmission of nonscrapie prion agents to sheep. The purpose of this review is to outline the current methods for diagnosing scrapie in sheep and the techniques used for studying the pathogenesis and host range of the scrapie agent. Also discussed is the US scrapie eradication program including recent updates.
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MATSUURA Y, MIYAZAWA K, IMAMURA M, YOKOYAMA T, IWAMARU Y. First case of atypical scrapie in a goat in Japan. J Vet Med Sci 2019; 81:986-989. [PMID: 31092762 PMCID: PMC6656802 DOI: 10.1292/jvms.18-0710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 05/05/2019] [Indexed: 11/22/2022] Open
Abstract
Atypical scrapie in goats has only been reported in European countries. The present study reports the identification of the first case of atypical scrapie in goats in Japan. The genotype of the animal was ALRQ/ALHQ at codons 136, 141, 154, and 171 in prion protein (PrP). Western blot analysis showed a multiplex proteinase K-resistant prion protein (PrP-res) band pattern with a band <15 kDa that was clearly distinguishable from the triplet PrP-res band pattern observed in classical scrapie cases. Histopathological and immunohistological examination showed mild vacuolation and fine granular to globular immunolabelling of disease-associated PrP in the dorsal horn of cervical spinal cord. Collectively, our results confirmed that this goat was affected by atypical scrapie.
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Affiliation(s)
- Yuichi MATSUURA
- National Institute of Animal Health (NIAH), National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-0856, Japan
| | - Kohtaro MIYAZAWA
- National Institute of Animal Health (NIAH), National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-0856, Japan
| | - Morikazu IMAMURA
- Division of Microbiology, Department of Infectious Diseases, Faculty of Medicine, Miyazaki University, Miyazaki 889-1692, Japan
| | - Takashi YOKOYAMA
- National Institute of Animal Health (NIAH), National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-0856, Japan
| | - Yoshifumi IWAMARU
- National Institute of Animal Health (NIAH), National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-0856, Japan
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Abstract
Scrapie is a naturally occurring transmissible spongiform encephalopathy (TSE) or prion disease of sheep and goats. Scrapie is a protein misfolding disease where the normal prion protein (PrPC) misfolds into a pathogenic form (PrPSc) that is highly resistant to enzymatic breakdown within the cell and accumulates, eventually leading to neurodegeneration. The amino acid sequence of the prion protein and tissue distribution of PrPSc within affected hosts have a major role in determining susceptibility to and potential environmental contamination with the scrapie agent. Many countries have genotype-based eradication programs that emphasize using rams that express arginine at codon 171 in the prion protein, which is associated with resistance to the classical scrapie agent. In classical scrapie, accumulation of PrPSc within lymphoid and other tissues facilitates environmental contamination and spread of the disease within flocks. A major distinction can be made between classical scrapie strains that are readily spread within populations of susceptible sheep and goats and atypical (Nor-98) scrapie that has unique molecular and phenotype characteristics and is thought to occur spontaneously in older sheep or goats. This review provides an overview of classical and atypical scrapie with consideration of potential transmission of classical scrapie to other mammalian hosts.
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Affiliation(s)
- Justin J Greenlee
- 1 Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, USA
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Cook RW, Bingham J, Besier AS, Bayley CL, Hawes M, Shearer PL, Yamada M, Bergfeld J, Williams DT, Middleton DJ. Atypical scrapie in Australia. Aust Vet J 2016; 94:452-455. [PMID: 27807855 DOI: 10.1111/avj.12529] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/06/2016] [Accepted: 04/14/2016] [Indexed: 12/21/2022]
Abstract
BACKGROUND Since its initial detection in Norway in 1998, atypical scrapie ('atypical/Nor98 scrapie') has been reported in sheep in the majority of European countries (including in regions free of classical scrapie) and in the Falkland Islands, the USA, Canada, New Zealand and Australia. CASE SERIES The diagnosis in Australia of atypical scrapie in four Merino and one Merino-cross sheep showing clinical signs of neurological disease was based on the detection of grey matter neuropil vacuolation (spongiform change) in the brain (particularly in the molecular layer of the cerebellar cortex) and associated abnormal prion protein (PrPSc ) deposition in both grey and white matter. Changes were minimal in the caudal brainstem, the predilection site for lesions of classical scrapie. CONCLUSION The distinctive lesion profile of atypical scrapie in these five sheep highlights the diagnostic importance of routine histological evaluation of the cerebellum for evidence of neuropil vacuolation and associated PrPSc deposition in adult sheep with suspected neurological disease.
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Affiliation(s)
- R W Cook
- Regional Veterinary Laboratory, NSW Department of Primary Industries, Wollongbar, New South Wales 2480, Australia
| | - J Bingham
- CSIRO, Australian Animal Health Laboratory, Geelong, Victoria, Australia
| | - A S Besier
- Animal Health Laboratories, Department of Agriculture and Food, South Perth, Western Australia, Australia
| | - C L Bayley
- Gribbles Veterinary Pathology, Clayton, Victoria, Australia
| | - M Hawes
- Department of Economic Development, AgriBio Centre, Bundoora, Victoria, Australia
| | - P L Shearer
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, New South Wales, Australia
| | - M Yamada
- CSIRO, Australian Animal Health Laboratory, Geelong, Victoria, Australia
| | - J Bergfeld
- CSIRO, Australian Animal Health Laboratory, Geelong, Victoria, Australia
| | - D T Williams
- CSIRO, Australian Animal Health Laboratory, Geelong, Victoria, Australia
| | - D J Middleton
- CSIRO, Australian Animal Health Laboratory, Geelong, Victoria, Australia
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Imamura M, Miyazawa K, Iwamaru Y, Matsuura Y, Yokoyama T, Okada H. Identification of the first case of atypical scrapie in Japan. J Vet Med Sci 2016; 78:1915-1919. [PMID: 27616556 PMCID: PMC5240776 DOI: 10.1292/jvms.16-0379] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A Corriedale ewe was confirmed as the first atypical scrapie case during an active surveillance program for transmissible spongiform encephalopathies in small ruminants in Japan. The animal was homozygous for the AF141RQ haplotype of PRNP. The animal showed clinical neurological signs possibly due to listeriosis before culling. Western blot analysis showed an unusual multiple banded pattern with a low-molecular fragment at ~7 kDa. Histopathology revealed suppurative meningoencephalitis caused by listeriosis in the brainstem. Fine granular to globular immunostaining of disease-associated prion proteins was mainly detected in the neuropil of the spinal tract of the trigeminal nerve and in the white matter of the spinocerebellar tract. Based on these results, this case was conclusively diagnosed as atypical scrapie with encephalitic listeriosis.
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Affiliation(s)
- Morikazu Imamura
- National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-0856, Japan
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Okada H, Miyazawa K, Imamura M, Iwamaru Y, Masujin K, Matsuura Y, Yokoyama T. Transmission of atypical scrapie to homozygous ARQ sheep. J Vet Med Sci 2016; 78:1619-1624. [PMID: 27320968 PMCID: PMC5095634 DOI: 10.1292/jvms.16-0259] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Two Cheviot ewes homozygous for the A136L141R154Q171 (AL141RQ) prion protein (PrP) genotype were exposed intracerebrally to brain pools prepared using four field cases of atypical scrapie from the United Kingdom. Animals were clinically normal until the end of the experiment, when they were culled 7 years post-inoculation. Limited accumulation of disease-associated PrP (PrPSc) was observed in the cerebellar molecular layer by immunohistochemistry, but not by western blot or enzyme-linked immunosorbent assay. In addition, PrPSc was partially localized in astrocytes and microglia, suggesting that these cells have a role in PrPSc processing, degradation or both. Our results indicate that atypical scrapie is transmissible to AL141RQ sheep, but these animals act as clinically silent carriers with long incubation times.
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Affiliation(s)
- Hiroyuki Okada
- National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-0856, Japan
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Abstract
Prion diseases or transmissible spongiform encephalopathies (TSEs) are fatal protein-misfolding neurodegenerative diseases. TSEs have been described in several species, including bovine spongiform encephalopathy (BSE) in cattle, scrapie in sheep and goats, chronic wasting disease (CWD) in cervids, transmissible mink encephalopathy (TME) in mink, and Kuru and Creutzfeldt-Jakob disease (CJD) in humans. These diseases are associated with the accumulation of a protease-resistant, disease-associated isoform of the prion protein (called PrP(Sc)) in the central nervous system and other tissues, depending on the host species. Typically, TSEs are acquired through exposure to infectious material, but inherited and spontaneous TSEs also occur. All TSEs share pathologic features and infectious mechanisms but have distinct differences in transmission and epidemiology due to host factors and strain differences encoded within the structure of the misfolded prion protein. The possibility that BSE can be transmitted to humans as the cause of variant Creutzfeldt-Jakob disease has brought attention to this family of diseases. This review is focused on the TSEs of livestock: bovine spongiform encephalopathy in cattle and scrapie in sheep and goats.
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Affiliation(s)
- Justin J Greenlee
- Justin J. Greenlee, DVM, PhD, Diplomate ACVP, is a research veterinary medical officer in the Virus and Prion Research Unit of the National Animal Disease Center, U.S. Department of Agriculture, Agricultural Research Service in Ames, Iowa. M. Heather West Greenlee, PhD, is an associate professor of biomedical sciences at the Iowa State University College of Veterinary Medicine
| | - M Heather West Greenlee
- Justin J. Greenlee, DVM, PhD, Diplomate ACVP, is a research veterinary medical officer in the Virus and Prion Research Unit of the National Animal Disease Center, U.S. Department of Agriculture, Agricultural Research Service in Ames, Iowa. M. Heather West Greenlee, PhD, is an associate professor of biomedical sciences at the Iowa State University College of Veterinary Medicine
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Kdidi S, Yahyaoui M, Conte M, Chiappini B, Zaccaria G, Ben Sassi M, Ben Ammar El Gaaied A, Khorchani T, Vaccari G. PRNP polymorphisms in Tunisian sheep breeds. Livest Sci 2014. [DOI: 10.1016/j.livsci.2014.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Prion protein misfolding, strains, and neurotoxicity: an update from studies on Mammalian prions. Int J Cell Biol 2013; 2013:910314. [PMID: 24454379 PMCID: PMC3884631 DOI: 10.1155/2013/910314] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 11/10/2013] [Accepted: 11/11/2013] [Indexed: 11/17/2022] Open
Abstract
Prion diseases, also known as transmissible spongiform encephalopathies (TSEs), are a group of fatal neurodegenerative disorders affecting humans and other mammalian species. The central event in TSE pathogenesis is the conformational conversion of the cellular prion protein, PrPC, into the aggregate, β-sheet rich, amyloidogenic form, PrPSc. Increasing evidence indicates that distinct PrPSc conformers, forming distinct ordered aggregates, can encipher the phenotypic TSE variants related to prion strains. Prion strains are TSE isolates that, after inoculation into syngenic hosts, cause disease with distinct characteristics, such as incubation period, pattern of PrPSc distribution, and regional severity of histopathological changes in the brain. In analogy with other amyloid forming proteins, PrPSc toxicity is thought to derive from the existence of various intermediate structures prior to the amyloid fiber formation and/or their specific interaction with membranes. The latter appears particularly relevant for the pathogenesis of TSEs associated with GPI-anchored PrPSc, which involves major cellular membrane distortions in neurons. In this review, we update the current knowledge on the molecular mechanisms underlying three fundamental aspects of the basic biology of prions such as the putative mechanism of prion protein conversion to the pathogenic form PrPSc and its propagation, the molecular basis of prion strains, and the mechanism of induced neurotoxicity by PrPSc aggregates.
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Pirisinu L, Nonno R, Esposito E, Benestad SL, Gambetti P, Agrimi U, Zou WQ. Small ruminant nor98 prions share biochemical features with human gerstmann-sträussler-scheinker disease and variably protease-sensitive prionopathy. PLoS One 2013; 8:e66405. [PMID: 23826096 PMCID: PMC3691246 DOI: 10.1371/journal.pone.0066405] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 05/06/2013] [Indexed: 01/08/2023] Open
Abstract
Prion diseases are classically characterized by the accumulation of pathological prion protein (PrPSc) with the protease resistant C-terminal fragment (PrPres) of 27–30 kDa. However, in both humans and animals, prion diseases with atypical biochemical features, characterized by PK-resistant PrP internal fragments (PrPres) cleaved at both the N and C termini, have been described. In this study we performed a detailed comparison of the biochemical features of PrPSc from atypical prion diseases including human Gerstmann-Sträussler-Scheinker disease (GSS) and variably protease-sensitive prionopathy (VPSPr) and in small ruminant Nor98 or atypical scrapie. The kinetics of PrPres production and its cleavage sites after PK digestion were analyzed, along with the PrPSc conformational stability, using a new method able to characterize both protease-resistant and protease-sensitive PrPSc components. All these PrPSc types shared common and distinctive biochemical features compared to PrPSc from classical prion diseases such as sporadic Creutzfeldt-Jakob disease and scrapie. Notwithstanding, distinct biochemical signatures based on PrPres cleavage sites and PrPSc conformational stability were identified in GSS A117V, GSS F198S, GSS P102L and VPSPr, which allowed their specific identification. Importantly, the biochemical properties of PrPSc from Nor98 and GSS P102L largely overlapped, but were distinct from the other human prions investigated. Finally, our study paves the way towards more refined comparative approaches to the characterization of prions at the animal–human interface.
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Affiliation(s)
- Laura Pirisinu
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
- * E-mail: (LP); (WQZ)
| | - Romolo Nonno
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Elena Esposito
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | | | - Pierluigi Gambetti
- Department of Pathology, National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Umberto Agrimi
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Wen-Quan Zou
- Department of Pathology, National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- * E-mail: (LP); (WQZ)
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Meydan H, Özkan MM, Yildiz MA. Genetic risk assessment for atypical scrapie in Turkish native sheep breeds. Small Rumin Res 2013. [DOI: 10.1016/j.smallrumres.2012.08.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kittelberger R, Chaplin MJ, Simmons MM, Ramirez-Villaescusa A, McIntyre L, MacDiarmid SC, Hannah MJ, Jenner J, Bueno R, Bayliss D, Black H, Pigott CJ, O'Keefe JS. Atypical scrapie/Nor98 in a sheep from New Zealand. J Vet Diagn Invest 2011; 22:863-75. [PMID: 21088169 DOI: 10.1177/104063871002200604] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In a consignment of sheep brains from New Zealand, to be used in Europe as negative control material in scrapie rapid screening test evaluations, brain samples from 1 sheep (no. 1512) gave the following initially confusing results in various screening tests: the brainstem repeatedly produced negative results in 2 very similar screening kits (enzyme-linked immunosorbent assay [ELISA]-1, ELISA-2), a macerate made from brainstem and cerebellum returned a clearly positive result in ELISA-2, and the macerate and a brainstem sample gave negative results in a third screening test (ELISA-3). In subsequent testing, cerebellum tissue alone tested strongly positive in ELISA-1 and produced a banding pattern very similar to atypical scrapie/Nor98 in a confirmatory Western blot (WB). The macerate showed weak staining in the confirmatory WB but presented a staining pattern identical to atypical scrapie/Nor98 in the scrapie-associated fibril WB. The latter test confirmed conclusively the first case of atypical scrapie/Nor98 in a sheep from New Zealand. Other parts of the brain either tested negative or very weak positive in ELISA-2 and in WBs, or tested with negative results by histopathology and immunohistochemistry. It appears that sheep no. 1512 is a case of atypical scrapie/Nor98 in which the abnormal prion protein was detected mainly in the cerebellum. This case emphasizes the need to retain brainstem, and cerebral and cerebellar tissues, as frozen and fixed materials, for conclusive confirmatory testing. Furthermore, consideration should be given to which screening method to use.
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Affiliation(s)
- Reinhold Kittelberger
- Investigation and Diagnostic Centre Wallaceville, Biosecurity New Zealand, Ministry of Agriculture and Forestry, PO Box 40742, Upper Hutt 5140, New Zealand.
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Seuberlich T, Heim D, Zurbriggen A. Atypical transmissible spongiform encephalopathies in ruminants: a challenge for disease surveillance and control. J Vet Diagn Invest 2011; 22:823-42. [PMID: 21088166 DOI: 10.1177/104063871002200601] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Since 1987, when bovine spongiform encephalopathy (BSE) emerged as a novel disease in cattle, enormous efforts were undertaken to monitor and control the disease in ruminants worldwide. The driving force was its high economic impact, which resulted from trade restrictions and the loss of consumer confidence in beef products, the latter because BSE turned out to be a fatal zoonosis, causing variant Creutzfeldt-Jakob disease in human beings. The ban on meat and bone meal in livestock feed and the removal of specified risk materials from the food chain were the main measures to successfully prevent infection in cattle and to protect human beings from BSE exposure. However, although BSE is now under control, previously unknown, so-called atypical transmissible spongiform encephalopathies (TSEs) in cattle and small ruminants have been identified by enhanced disease surveillance. This report briefly reviews and summarizes the current level of knowledge on the spectrum of TSEs in cattle and small ruminants and addresses the question of the extent to which such atypical TSEs have an effect on disease surveillance and control strategies.
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Affiliation(s)
- Torsten Seuberlich
- NeuroCentre, National and OIE Reference Laboratories for BSE and Scrapie, DCR-VPH, Bremgartenstrasse 109a, CH-3001 Berne, Switzerland.
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Abstract
Although prion diseases, such as Creutzfeldt-Jakob disease (CJD) in humans and scrapie in sheep, have long been recognized, our understanding of their epidemiology and pathogenesis is still in its early stages. Progress is hampered by the lengthy incubation periods and the lack of effective ways of monitoring and characterizing these agents. Protease-resistant conformers of the prion protein (PrP), known as the "scrapie form" (PrP(Sc)), are used as disease markers, and for taxonomic purposes, in correlation with clinical, pathological, and genetic data. In humans, prion diseases can arise sporadically (sCJD) or genetically (gCJD and others), caused by mutations in the PrP-gene (PRNP), or as a foodborne infection, with the agent of bovine spongiform encephalopathy (BSE) causing variant CJD (vCJD). Person-to-person spread of human prion disease has only been known to occur following cannibalism (kuru disease in Papua New Guinea) or through medical or surgical treatment (iatrogenic CJD, iCJD). In contrast, scrapie in small ruminants and chronic wasting disease (CWD) in cervids behave as infectious diseases within these species. Recently, however, so-called atypical forms of prion diseases have been discovered in sheep (atypical/Nor98 scrapie) and in cattle, BSE-H and BSE-L. These maladies resemble sporadic or genetic human prion diseases and might be their animal equivalents. This hypothesis also raises the significant public health question of possible epidemiological links between these diseases and their counterparts in humans.
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Loiacono CM, Beckwith N, Kunkle RA, Orcutt D, Hall SM. Detection of PrP(Sc) in formalin-fixed, paraffin-embedded tissue by Western blot differentiates classical scrapie, Nor98 scrapie, and bovine spongiform encephalopathy. J Vet Diagn Invest 2010; 22:684-9. [PMID: 20807921 DOI: 10.1177/104063871002200502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Transmissible, spongiform encephalopathies including bovine spongiform encephalopathy (BSE) and scrapie are fatal neurodegenerative disorders associated with the presence of an infectious abnormal isoform of normal mammalian proteins called prions. Identification of the prion protein associated with scrapie (PrP(Sc)) in the central nervous system is typically based upon immunoassays including immunohistochemistry (IHC) using formalin-fixed tissues or Western blot (WB) assays using fresh and/or frozen, non-formalin-fixed tissues. Each assay can discriminate between BSE, classical scrapie, and a previously reported strain of scrapie recently identified in the United States named Nor98 scrapie. Different tissue samples are required from the same animal to run these 2 different immunoassays. This may result in inconsistent test results for the same animal. Sampling problems such as collecting insufficient volumes of fresh tissue or less than optimal anatomic location of brainstem for IHC can affect the ability of the test procedures to offer definitive and discriminatory results. Recently, a WB method using formalin-fixed, paraffin-embedded (FFPE) tissue to identify PrP(Sc) was developed that successfully identified PrP(Sc) in sheep affected by classical scrapie. In the current study, the use of this technique to produce discriminatory results identifying classical BSE in bovine tissue and both classical and Nor98 scrapie in ovine tissue using paraffin-embedded brain samples is described. Protein-banding patterns from WB using FFPE tissue were similar to protein-banding patterns produced by WB assays utilizing fresh tissues from the same animals, and results correlated well with the IHC PrP(Sc)-positive staining present in the cerebellum and obex regions of brain samples from these animals.
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Affiliation(s)
- Christina M Loiacono
- Animal and Plant Health Inspection Services, National Veterinary Services Laboratories, Pathobiology Laboratory, U.S. Department of Agriculture, Ames, IA 50010, USA.
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Mitchell GB, O'Rourke KI, Harrington NP, Soutyrine A, Simmons MM, Dudas S, Zhuang D, Laude H, Balachandran A. Identification of atypical scrapie in Canadian sheep. J Vet Diagn Invest 2010; 22:408-11. [PMID: 20453215 DOI: 10.1177/104063871002200310] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Scrapie, a transmissible spongiform encephalopathy of sheep and goats, exists in most small ruminant-producing countries of the world. A novel form of this disease was recently recognized and is known by various names, including Nor98, Nor98-like, and atypical scrapie. Differing from classic scrapie in epidemiology, histopathology, and biochemical characteristics, atypical scrapie cases have been identified throughout Europe and in the United States. Enhanced scrapie surveillance efforts recently identified 3 cases of atypical scrapie in Canada.
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Affiliation(s)
- Gordon B Mitchell
- Canadian Food Inspection Agency, Ottawa Laboratory-Fallowfield, 3851 Fallowfield Road, Ottawa, Ontario, Canada, K2H 8P9
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Simmons MM, Konold T, Thurston L, Bellworthy SJ, Chaplin MJ, Moore SJ. The natural atypical scrapie phenotype is preserved on experimental transmission and sub-passage in PRNP homologous sheep. BMC Vet Res 2010; 6:14. [PMID: 20219126 PMCID: PMC2848638 DOI: 10.1186/1746-6148-6-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Accepted: 03/10/2010] [Indexed: 11/26/2022] Open
Abstract
Background Atypical scrapie was first identified in Norwegian sheep in 1998 and has subsequently been identified in many countries. Retrospective studies have identified cases predating the initial identification of this form of scrapie, and epidemiological studies have indicated that it does not conform to the behaviour of an infectious disease, giving rise to the hypothesis that it represents spontaneous disease. However, atypical scrapie isolates have been shown to be infectious experimentally, through intracerebral inoculation in transgenic mice and sheep. The first successful challenge of a sheep with 'field' atypical scrapie from an homologous donor sheep was reported in 2007. Results This study demonstrates that atypical scrapie has distinct clinical, pathological and biochemical characteristics which are maintained on transmission and sub-passage, and which are distinct from other strains of transmissible spongiform encephalopathies in the same host genotype. Conclusions Atypical scrapie is consistently transmissible within AHQ homozygous sheep, and the disease phenotype is preserved on sub-passage.
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Affiliation(s)
- Marion M Simmons
- Department of Pathology, Veterinary Laboratories Agency Weybridge, New Haw, Addlestone KT15 3NB, UK.
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Co-existence of classical scrapie and Nor98 in a sheep from an Italian outbreak. Res Vet Sci 2009; 88:478-85. [PMID: 20031179 DOI: 10.1016/j.rvsc.2009.11.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 11/23/2009] [Accepted: 11/25/2009] [Indexed: 11/22/2022]
Abstract
Nor98 is an atypical scrapie strain characterized by a molecular pattern and brain distribution of the pathological prion protein (PrP(Sc)) different from classical scrapie. In Italy, 69 atypical cases have been identified so far and all were characterized as Nor98 strain. In this paper we report an unusual case in a sheep which showed immunohistochemical and molecular features of PrP(Sc) different from the other atypical cases. The sheep was from an outbreak where the index and the other four cases were affected by classical scrapie. Histopathological, immunohistochemical and Western blot analyses on the brain of the unusual case revealed the simultaneous presence of pathological features characteristic of Nor98 and classical scrapie. Interestingly, the prevalent disease phenotype in the brainstem was classical scrapie-like, while in the cerebral cortex and cerebellum the Nor98 phenotype was dominant. The sub-mandibular lymph node was positive and showed a PrP(Sc) molecular pattern referable to classical scrapie. The PrP genotype was AL(141)RQ/AF(141)RQ. Taken together, the occurrence of classical scrapie in the outbreak, the PrP genotype, the involvement of different cellular targets in the brain and the pathological and molecular PrP(Sc) features observed suggest that this unusual case may result from the co-existence of Nor98 and classical scrapie.
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