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Simmons SM, Bartz JC. Strain-Specific Targeting and Destruction of Cells by Prions. BIOLOGY 2024; 13:57. [PMID: 38275733 PMCID: PMC10813089 DOI: 10.3390/biology13010057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/11/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024]
Abstract
Prion diseases are caused by the disease-specific self-templating infectious conformation of the host-encoded prion protein, PrPSc. Prion strains are operationally defined as a heritable phenotype of disease under controlled conditions. One of the hallmark phenotypes of prion strain diversity is tropism within and between tissues. A defining feature of prion strains is the regional distribution of PrPSc in the CNS. Additionally, in both natural and experimental prion disease, stark differences in the tropism of prions in secondary lymphoreticular system tissues occur. The mechanism underlying prion tropism is unknown; however, several possible hypotheses have been proposed. Clinical target areas are prion strain-specific populations of neurons within the CNS that are susceptible to neurodegeneration following the replication of prions past a toxic threshold. Alternatively, the switch from a replicative to toxic form of PrPSc may drive prion tropism. The normal form of the prion protein, PrPC, is required for prion formation. More recent evidence suggests that it can mediate prion and prion-like disease neurodegeneration. In vitro systems for prion formation have indicated that cellular cofactors contribute to prion formation. Since these cofactors can be strain specific, this has led to the hypothesis that the distribution of prion formation cofactors can influence prion tropism. Overall, there is evidence to support several mechanisms of prion strain tropism; however, a unified theory has yet to emerge.
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Affiliation(s)
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE 68178, USA;
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2
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Garza MC, Kang SG, Kim C, Monleón E, van der Merwe J, Kramer DA, Fahlman R, Sim VL, Aiken J, McKenzie D, Cortez LM, Wille H. In Vitro and In Vivo Evidence towards Fibronectin's Protective Effects against Prion Infection. Int J Mol Sci 2023; 24:17525. [PMID: 38139358 PMCID: PMC10743696 DOI: 10.3390/ijms242417525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/08/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
A distinctive signature of the prion diseases is the accumulation of the pathogenic isoform of the prion protein, PrPSc, in the central nervous system of prion-affected humans and animals. PrPSc is also found in peripheral tissues, raising concerns about the potential transmission of pathogenic prions through human food supplies and posing a significant risk to public health. Although muscle tissues are considered to contain levels of low prion infectivity, it has been shown that myotubes in culture efficiently propagate PrPSc. Given the high consumption of muscle tissue, it is important to understand what factors could influence the establishment of a prion infection in muscle tissue. Here we used in vitro myotube cultures, differentiated from the C2C12 myoblast cell line (dC2C12), to identify factors affecting prion replication. A range of experimental conditions revealed that PrPSc is tightly associated with proteins found in the systemic extracellular matrix, mostly fibronectin (FN). The interaction of PrPSc with FN decreased prion infectivity, as determined by standard scrapie cell assay. Interestingly, the prion-resistant reserve cells in dC2C12 cultures displayed a FN-rich extracellular matrix while the prion-susceptible myotubes expressed FN at a low level. In agreement with the in vitro results, immunohistopathological analyses of tissues from sheep infected with natural scrapie demonstrated a prion susceptibility phenotype linked to an extracellular matrix with undetectable levels of FN. Conversely, PrPSc deposits were not observed in tissues expressing FN. These data indicate that extracellular FN may act as a natural barrier against prion replication and that the extracellular matrix composition may be a crucial feature determining prion tropism in different tissues.
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Affiliation(s)
- M. Carmen Garza
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Sang-Gyun Kang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Chiye Kim
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Eva Monleón
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, Departamento de Anatomía e Histología Humana, Universidad de Zaragoza, IA2, IIS Aragón, 50013 Zaragoza, Spain
| | - Jacques van der Merwe
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - David A. Kramer
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 1C9, Canada
| | - Richard Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Valerie L. Sim
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2G3, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Judd Aiken
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Department of Agriculture, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 1C9, Canada
| | - Debbie McKenzie
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Leonardo M. Cortez
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2G3, Canada
| | - Holger Wille
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada; (M.C.G.); (S.-G.K.); (J.v.d.M.); (V.L.S.); (D.M.)
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
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Pineau H, Sim VL. From Cell Culture to Organoids-Model Systems for Investigating Prion Strain Characteristics. Biomolecules 2021; 11:biom11010106. [PMID: 33466947 PMCID: PMC7830147 DOI: 10.3390/biom11010106] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/06/2023] Open
Abstract
Prion diseases are the hallmark protein folding neurodegenerative disease. Their transmissible nature has allowed for the development of many different cellular models of disease where prion propagation and sometimes pathology can be induced. This review examines the range of simple cell cultures to more complex neurospheres, organoid, and organotypic slice cultures that have been used to study prion disease pathogenesis and to test therapeutics. We highlight the advantages and disadvantages of each system, giving special consideration to the importance of strains when choosing a model and when interpreting results, as not all systems propagate all strains, and in some cases, the technique used, or treatment applied, can alter the very strain properties being studied.
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Affiliation(s)
- Hailey Pineau
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2B7, Canada;
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Valerie L. Sim
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2B7, Canada;
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2R3, Canada
- Correspondence:
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4
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The Role of Vesicle Trafficking Defects in the Pathogenesis of Prion and Prion-Like Disorders. Int J Mol Sci 2020; 21:ijms21197016. [PMID: 32977678 PMCID: PMC7582986 DOI: 10.3390/ijms21197016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 11/26/2022] Open
Abstract
Prion diseases are fatal and transmissible neurodegenerative diseases in which the cellular form of the prion protein ‘PrPc’, misfolds into an infectious and aggregation prone isoform termed PrPSc, which is the primary component of prions. Many neurodegenerative diseases, like Alzheimer’s disease, Parkinson’s disease, and polyglutamine diseases, such as Huntington’s disease, are considered prion-like disorders because of the common characteristics in the propagation and spreading of misfolded proteins that they share with the prion diseases. Unlike prion diseases, these are non-infectious outside experimental settings. Many vesicular trafficking impairments, which are observed in prion and prion-like disorders, favor the accumulation of the pathogenic amyloid aggregates. In addition, many of the vesicular trafficking impairments that arise in these diseases, turn out to be further aggravating factors. This review offers an insight into the currently known vesicular trafficking defects in these neurodegenerative diseases and their implications on disease progression. These findings suggest that these impaired trafficking pathways may represent similar therapeutic targets in these classes of neurodegenerative disorders.
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Moore SJ, Smith JD, Richt JA, Greenlee JJ. Raccoons accumulate PrP Sc after intracranial inoculation of the agents of chronic wasting disease or transmissible mink encephalopathy but not atypical scrapie. J Vet Diagn Invest 2019; 31:200-209. [PMID: 30694116 DOI: 10.1177/1040638718825290] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Prion diseases are neurodegenerative diseases characterized by the accumulation of misfolded prion protein (PrPSc) in the brain and other tissues. Animal prion diseases include scrapie in sheep, chronic wasting disease (CWD) in cervids, and transmissible mink encephalopathy (TME) in ranch-raised mink. We investigated the susceptibility of raccoons to various prion disease agents and compared the clinicopathologic features of the resulting disease. Raccoon kits were inoculated intracranially with the agents of raccoon-passaged TME (TMERac), bovine-passaged TME (TMEBov), hamster-adapted drowsy (TMEDY) or hyper TME (TMEHY), CWD from white-tailed deer (CWDWtd) or elk (CWDElk), or atypical (Nor98) scrapie. Raccoons were euthanized when they developed clinical signs of prion disease or at study endpoint (<82 mo post-inoculation). Brain was examined for the presence of spongiform change, and disease-associated PrPSc was detected using an enzyme immunoassay, western blot, and immunohistochemistry. All raccoons inoculated with the agents of TMERac and TMEBov developed clinical disease at ~6.6 mo post-inoculation, with widespread PrPSc accumulation in central nervous system tissues. PrPSc was detected in the brain of 1 of 4 raccoons in each of the CWDWtd-, CWDElk-, and TMEHY-inoculated groups. None of the raccoons inoculated with TMEDY or atypical scrapie agents developed clinical disease or detectable PrPSc accumulation. Our results indicate that raccoons are highly susceptible to infection with raccoon- and bovine-passaged TME agents, whereas CWD isolates from white-tailed deer or elk and hamster-adapted TMEHY transmit poorly. Raccoons appear to be resistant to infection with hamster-adapted TMEDY and atypical scrapie agents.
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Affiliation(s)
- S Jo Moore
- National Animal Disease Center, Ames, IA (Moore, Greenlee).,Iowa State University, College of Veterinary Medicine, Ames, IA (Smith).,Kansas State University, College of Veterinary Medicine, Manhattan, KS (Richt)
| | - Jodi D Smith
- National Animal Disease Center, Ames, IA (Moore, Greenlee).,Iowa State University, College of Veterinary Medicine, Ames, IA (Smith).,Kansas State University, College of Veterinary Medicine, Manhattan, KS (Richt)
| | - Jürgen A Richt
- National Animal Disease Center, Ames, IA (Moore, Greenlee).,Iowa State University, College of Veterinary Medicine, Ames, IA (Smith).,Kansas State University, College of Veterinary Medicine, Manhattan, KS (Richt)
| | - Justin J Greenlee
- National Animal Disease Center, Ames, IA (Moore, Greenlee).,Iowa State University, College of Veterinary Medicine, Ames, IA (Smith).,Kansas State University, College of Veterinary Medicine, Manhattan, KS (Richt)
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Diack AB, Bartz JC. Experimental models of human prion diseases and prion strains. HANDBOOK OF CLINICAL NEUROLOGY 2018; 153:69-84. [PMID: 29887156 DOI: 10.1016/b978-0-444-63945-5.00004-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Prion strains occur in natural prion diseases, including prion diseases of humans. Prion strains can correspond with differences in the clinical signs and symptoms of disease and the distribution of prion infectivity in the host and are hypothesized to be encoded by strain-specific differences in the conformation of the disease-specific isoform of the host-encoded prion protein, PrPTSE. Prion strains can differ in biochemical properties of PrPTSE that can include the relative sensitivity to digestion with proteinase K and conformational stability in denaturants. These strain-specific biochemical properties of field isolates are maintained upon transmission to experimental animal models of prion disease. Experimental human models of prion disease include traditional and gene-targeted mice that express endogenous PrPC. Transgenic mice that express different polymorphs of human PrPC or mutations in human PrPC that correspond with familial forms of human prion disease have been generated that can recapitulate the clinical, pathologic, and biochemical features of disease. These models aid in understanding disease pathogenesis, evaluating zoonotic potential of animal prion diseases, and assessing human-to-human transmission of disease. Models of sporadic or familial forms of disease offer an opportunity to define mechanisms of disease, identify key neurodegenerative pathways, and assess therapeutic interventions.
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Affiliation(s)
- Abigail B Diack
- Infection and Immunity, The Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom.
| | - Jason C Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States
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Davydova L, Tkach G, Tymoshenko A, Moskalenko A, Sikora V, Kyptenko L, Lyndin M, Muravskyi D, Maksymova O, Suchonos O. Anatomical and morphological aspects of papillae, epithelium, muscles, and glands of rats' tongue: Light, scanning, and transmission electron microscopic study. Interv Med Appl Sci 2017; 9:168-177. [PMID: 29201443 PMCID: PMC5700697 DOI: 10.1556/1646.9.2017.21] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Purpose The purpose of this paper is to describe the research results of the morphological structure of white laboratory rats' tongue at the macro-, micro-, and ultrastructural levels by scanning, light, and transmission electron microscopy. Results Our results show that the tongue of these rats has a number of unique morphological features that are different from the tongue of other rodents consequently to allow identifying their species-specific features. Conclusions Our findings have shown the features of the tongue structure of white laboratory rats at micro-, macro-, and ultrascopic levels. The data analysis revealed that mucous membrane of the tongue contains a large number of papillae, such as fungiform, filiform, foliate, vallate, and multifilamentary papillae. Each has a different shape, size, and location. The tongue's morphological feature consists of three types of filiform papillae, well-developed foliate and multifilamentary papillae, as well as one large and similar smaller circumvallate papillae. The muscle of the tongue contains a large number of mitochondria of different shapes and sizes. However, we have received data for a complete picture of structure of this organ that will be useful in further experimental and morphological studies of the white laboratory rats.
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Affiliation(s)
- Ludmila Davydova
- Department of Normal Anatomy with Courses of the Topographical Anatomy, the Operational Surgery, Histology, Cytology and Embryology, Sumy State University, Sumy, Ukraine
| | - Gennadii Tkach
- Department of Normal Anatomy with Courses of the Topographical Anatomy, the Operational Surgery, Histology, Cytology and Embryology, Sumy State University, Sumy, Ukraine
| | - Alexey Tymoshenko
- Department of Family and Public Medicine, Section "Stomatology", Sumy State University, Sumy, Ukraine
| | - Alexey Moskalenko
- Department of Family and Public Medicine, Section "Stomatology", Sumy State University, Sumy, Ukraine
| | - Vitalii Sikora
- Department of Normal Anatomy with Courses of the Topographical Anatomy, the Operational Surgery, Histology, Cytology and Embryology, Sumy State University, Sumy, Ukraine
| | - Ludmila Kyptenko
- Department of Normal Anatomy with Courses of the Topographical Anatomy, the Operational Surgery, Histology, Cytology and Embryology, Sumy State University, Sumy, Ukraine
| | - Mykola Lyndin
- Department of Pathology, Sumy State University, Sumy, Ukraine
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Infectious Prions in the Pregnancy Microenvironment of Chronic Wasting Disease-Infected Reeves' Muntjac Deer. J Virol 2017; 91:JVI.00501-17. [PMID: 28539446 DOI: 10.1128/jvi.00501-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/05/2017] [Indexed: 11/20/2022] Open
Abstract
Ample evidence exists for the presence of infectious agents at the maternal-fetal interface, often with grave outcomes to the developing fetus (i.e., Zika virus, brucella, cytomegalovirus, and toxoplasma). While less studied, pregnancy-related transmissible spongiform encephalopathies (TSEs) have been implicated in several species, including humans. Our previous work has shown that prions can be transferred from mother to offspring, resulting in the development of clinical TSE disease in offspring born to muntjac dams infected with chronic wasting disease (CWD) (1). We further demonstrated protein misfolding cyclic amplification (PMCA)-competent prions within the female reproductive tract and in fetal tissues harvested from CWD experimentally and naturally exposed cervids (1, 2). To assess whether the PMCA-competent prions residing at the maternal-fetal interface were infectious and to determine if the real-time quaking-induced conversion (RT-QuIC) methodology may enhance our ability to detect amyloid fibrils within the pregnancy microenvironment, we employed a mouse bioassay and RT-QuIC. In this study, we have demonstrated RT-QuIC seeding activity in uterus, placentome, ovary, and amniotic fluid but not in allantoic fluids harvested from CWD-infected Reeves' muntjac dams showing clinical signs of infection (clinically CWD-infected) and in some placentomes from pre-clinically CWD-infected dams. Prion infectivity was confirmed within the uterus, amniotic fluid, and the placentome, the semipermeable interface that sustains the developing fetus, of CWD-infected dams. This is the first report of prion infectivity within the cervid pregnancy microenvironment, revealing a source of fetal CWD exposure prior to the birthing process, maternal grooming, or encounters with contaminated environments.IMPORTANCE The facile dissemination of chronic wasting disease within captive and free-range cervid populations has led to questions regarding the transmission dynamics of this disease. Direct contact with infected animals and indirect contact with infectious prions in bodily fluids and contaminated environments are suspected to explain the majority of this transmission. A third mode of transmission, from mother to offspring, may be underappreciated. The presence of pregnancy-related prion infectivity within the uterus, amniotic fluid, and the placental structure reveals that the developing fetus is exposed to a source of prions long before exposure to the infectious agent during and after the birthing process or via contact with contaminated environments. These findings have impact on our current concept of CWD disease transmission.
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Shikiya RA, Langenfeld KA, Eckland TE, Trinh J, Holec SAM, Mathiason CK, Kincaid AE, Bartz JC. PrPSc formation and clearance as determinants of prion tropism. PLoS Pathog 2017; 13:e1006298. [PMID: 28355274 PMCID: PMC5386299 DOI: 10.1371/journal.ppat.1006298] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 04/10/2017] [Accepted: 03/16/2017] [Indexed: 11/19/2022] Open
Abstract
Prion strains are characterized by strain-specific differences in neuropathology but can also differ in incubation period, clinical disease, host-range and tissue tropism. The hyper (HY) and drowsy (DY) strains of hamster-adapted transmissible mink encephalopathy (TME) differ in tissue tropism and susceptibility to infection by extraneural routes of infection. Notably, DY TME is not detected in the secondary lymphoreticular system (LRS) tissues of infected hosts regardless of the route of inoculation. We found that similar to the lymphotropic strain HY TME, DY TME crosses mucosal epithelia, enters draining lymphatic vessels in underlying laminae propriae, and is transported to LRS tissues. Since DY TME causes disease once it enters the peripheral nervous system, the restriction in DY TME pathogenesis is due to its inability to establish infection in LRS tissues, not a failure of transport. To determine if LRS tissues can support DY TME formation, we performed protein misfolding cyclic amplification using DY PrPSc as the seed and spleen homogenate as the source of PrPC. We found that the spleen environment can support DY PrPSc formation, although at lower rates compared to lymphotropic strains, suggesting that the failure of DY TME to establish infection in the spleen is not due to the absence of a strain-specific conversion cofactor. Finally, we provide evidence that DY PrPSc is more susceptible to degradation when compared to PrPSc from other lymphotrophic strains. We hypothesize that the relative rates of PrPSc formation and clearance can influence prion tropism.
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Affiliation(s)
- Ronald A. Shikiya
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Katie A. Langenfeld
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Thomas E. Eckland
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Jonathan Trinh
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Sara A. M. Holec
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Candace K. Mathiason
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Anthony E. Kincaid
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
- Department of Pharmacy Science, Creighton University, Omaha, Nebraska, United States of America
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
- * E-mail:
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Abstract
Prion diseases affect a wide range of mammal species and are caused by a misfolded self-propagating isoform (PrPSc) of the normal prion protein (PrPC). Distinct strains of prions exist and are operationally defined by differences in a heritable phenotype under controlled experimental transmission conditions. Prion strains can differ in incubation period, clinical signs of disease, tissue tropism, and host range. The mechanism by which a protein-only pathogen can encode strain diversity is only beginning to be understood. The prevailing hypothesis is that prion strain diversity is encoded by strain-specific conformations of PrPSc; however, strain-specific cellular cofactors have been identified in vitro that may also contribute to prion strain diversity. Although much progress has been made on understanding the etiological agent of prion disease, the relationship between the strain-specific properties of PrPSc and the resulting phenotype of disease in animals is poorly understood.
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Affiliation(s)
- Jason C Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska 68178
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11
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Moore SJ, Smith JD, Greenlee MHW, Nicholson EM, Richt JA, Greenlee JJ. Comparison of Two US Sheep Scrapie Isolates Supports Identification as Separate Strains. Vet Pathol 2016; 53:1187-1196. [DOI: 10.1177/0300985816629712] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Scrapie is a naturally occurring transmissible spongiform encephalopathy of sheep and goats. There are different strains of sheep scrapie that are associated with unique molecular, transmission, and phenotype characteristics. However, in the United States, very little is known about the potential presence of scrapie strains. Scrapie strain and PRNP genotype could both affect susceptibility, potential for transmission, incubation period (IP), and control measures required for eliminating scrapie from a flock. The investigators evaluated 2 US scrapie isolates, No. 13-7 and x124, after intranasal inoculation to compare clinical signs, IPs, spongiform lesions, and patterns of PrPSc deposition in sheep with scrapie-susceptible PRNP genotypes (QQ171). After inoculation with x124, susceptibility and IP were associated with valine at codon 136 (V136) of the prion protein: VV136 sheep had short IPs (6.9 months), those in AV136 sheep were 11.9 months, and AA136 sheep did not develop scrapie. All No. 13-7 inoculated sheep developed scrapie, with IPs of 20.1 months for AA136 sheep, 22.8 months for AV136 sheep, and 26.7 months for VV136 sheep. Patterns of immunoreactivity in the brain were influenced by inoculum isolate and host genotype. Differences in PrPSc profiles versus isolate were most striking when examining brains from sheep with the VV136 genotype. Inoculation into C57BL/6 mice resulted in markedly different attack rates (90.5% for x124 and 5.9% for No. 13-7). Taken together, these data demonstrate that No. 13-7 and x124 represent 2 distinct strains of scrapie with different IPs, genotype susceptibilities, and PrPSc deposition profiles.
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Affiliation(s)
- S. J. Moore
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA
| | - J. D. Smith
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA
| | - M. H. West Greenlee
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA
| | - E. M. Nicholson
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA
| | - J. A. Richt
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA
| | - J. J. Greenlee
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA
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Berrone E, Corona C, Mazza M, Costassa EV, Faro ML, Properzi F, Guglielmetti C, Maurella C, Caramelli M, Deregibus MC, Camussi G, Casalone C. Detection of cellular prion protein in exosomes derived from ovine plasma. J Gen Virol 2015; 96:3698-3702. [PMID: 26399471 PMCID: PMC4804764 DOI: 10.1099/jgv.0.000291] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 09/18/2015] [Indexed: 01/01/2023] Open
Abstract
Prion protein (PrP) is present at extremely low levels in the blood of animals and its detection is complicated by the poor sensitivity of current standard methodologies. Interesting results have been obtained with recent advanced technologies that are able to detect minute amounts of the pathological PrP (PrPSc), but their efficiency is reduced by various factors present in blood. In this study, we were able to extract cellular PrP (PrPC) from plasma-derived exosomes by a simple, fast method without the use of differential ultracentrifugation and to visualize it by Western blotting, reducing the presence of most plasma proteins. This result confirms that blood is capable of releasing PrP in association with exosomes and could be useful to better study its role in the pathogenesis of transmissible spongiform encephalopathies.
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Affiliation(s)
- Elena Berrone
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
| | - Cristiano Corona
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
| | - Maria Mazza
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
| | - Elena Vallino Costassa
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
| | - Monica Lo Faro
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
| | - Francesca Properzi
- Department of Cellular Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Chiara Guglielmetti
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
| | - Cristiana Maurella
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
| | - Maria Caramelli
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
| | - Maria Chiara Deregibus
- Department of Internal Medicine and Molecular Biotechnology Center, University of Turin, Corso Dogliotti 14, 10126 Turin, Italy
| | - Giovanni Camussi
- Department of Internal Medicine and Molecular Biotechnology Center, University of Turin, Corso Dogliotti 14, 10126 Turin, Italy
| | - Cristina Casalone
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Turin, Italy
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Neumann M, Krasemann S, Schröck K, Steinbach K, Glatzel M. Myositis facilitates preclinical accumulation of pathological prion protein in muscle. Acta Neuropathol Commun 2013; 1:78. [PMID: 24299111 PMCID: PMC4046662 DOI: 10.1186/2051-5960-1-78] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 11/01/2013] [Indexed: 11/18/2022] Open
Abstract
Background In human and animal prion diseases, pathological prion protein, PrPSc, as well as prion infectivity is mainly found in the central nervous system, but also in lymphoid organs and muscle. Pathophysiology of prion colonization of lymphoid organs has been studied intensively, yet how myositis influences prion accumulation in muscle is unknown. Result We have investigated the influence of myositis on PrPSc accumulation and prion infectivity in two distinct mouse models of experimental autoimmune myositis. Furthermore, we have addressed the relevance of PrPC expression in the lymphoreticular system in myositis by generating bone marrow chimeras. Here we show that myositis positively influences muscular PrPSc accumulation at preclinical time points and that PrPC-expression in the lymphoid system is critical for this. In muscle, PrPSc and prion infectivity are uncoupled with detectable PrPSc but no prion infectivity at preclinical time points. Muscle has an intrinsically high ability to clear PrPSc once myositis has ceased, possibly involving autophagy. Conclusion Our findings provide new insights into the pathophysiology of prion colonization in muscle pointing out that myositis leads to enhanced prion colonization of muscle in subclinical prion disease. Electronic supplementary material The online version of this article (doi:10.1186/2051-5960-1-78) contains supplementary material, which is available to authorized users.
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Tamgüney G, Richt JA, Hamir AN, Greenlee JJ, Miller MW, Wolfe LL, Sirochman TM, Young AJ, Glidden DV, Johnson NL, Giles K, DeArmond SJ, Prusiner SB. Salivary prions in sheep and deer. Prion 2012; 6:52-61. [PMID: 22453179 DOI: 10.4161/pri.6.1.16984] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Scrapie of sheep and chronic wasting disease (CWD) of cervids are transmissible prion diseases. Milk and placenta have been identified as sources of scrapie prions but do not explain horizontal transmission. In contrast, CWD prions have been reported in saliva, urine and feces, which are thought to be responsible for horizontal transmission. While the titers of CWD prions have been measured in feces, levels in saliva or urine are unknown. Because sheep produce ~17 L/day of saliva, and scrapie prions are present in tongue and salivary glands of infected sheep, we asked if scrapie prions are shed in saliva. We inoculated transgenic (Tg) mice expressing ovine prion protein, Tg(OvPrP) mice, with saliva from seven Cheviot sheep with scrapie. Six of seven samples transmitted prions to Tg(OvPrP) mice with titers of -0.5 to 1.7 log ID₅₀ U/ml. Similarly, inoculation of saliva samples from two mule deer with CWD transmitted prions to Tg(ElkPrP) mice with titers of -1.1 to -0.4 log ID₅₀ U/ml. Assuming similar shedding kinetics for salivary prions as those for fecal prions of deer, we estimated the secreted salivary prion dose over a 10-mo period to be as high as 8.4 log ID₅₀ units for sheep and 7.0 log ID₅₀ units for deer. These estimates are similar to 7.9 log ID₅₀ units of fecal CWD prions for deer. Because saliva is mostly swallowed, salivary prions may reinfect tissues of the gastrointestinal tract and contribute to fecal prion shedding. Salivary prions shed into the environment provide an additional mechanism for horizontal prion transmission.
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Affiliation(s)
- Gültekin Tamgüney
- Institute for Neurodegenerative Diseases, Department of Neurology, University of California, San Francisco, CA, USA
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Furness JB, Poole DP. NONRUMINANT NUTRITION SYMPOSIUM: Involvement of gut neural and endocrine systems in pathological disorders of the digestive tract1,2. J Anim Sci 2012; 90:1203-12. [DOI: 10.2527/jas.2011-4825] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Abstract
In this study, we investigated the role of damage to the nasal mucosa in the shedding of prions into nasal samples as a pathway for prion transmission. Here, we demonstrate that prions can replicate to high levels in the olfactory sensory epithelium (OSE) in hamsters and that induction of apoptosis in olfactory receptor neurons (ORNs) in the OSE resulted in sloughing off of the OSE from nasal turbinates into the lumen of the nasal airway. In the absence of nasotoxic treatment, olfactory marker protein (OMP), which is specific for ORNs, was not detected in nasal lavage samples. However, after nasotoxic treatment that leads to apoptosis of ORNs, both OMP and prion proteins were present in nasal lavage samples. The cellular debris that was released from the OSE into the lumen of the nasal airway was positive for both OMP and the disease-specific isoform of the prion protein, PrP(Sc). By using the real-time quaking-induced conversion assay to quantify prions, a 100- to 1,000-fold increase in prion seeding activity was observed in nasal lavage samples following nasotoxic treatment. Since neurons replicate prions to higher levels than other cell types and ORNs are the most environmentally exposed neurons, we propose that an increase in ORN apoptosis or damage to the nasal mucosa in a host with a preexisting prion infection of the OSE could lead to a substantial increase in the release of prion infectivity into nasal samples. This mechanism of prion shedding from the olfactory mucosa could contribute to prion transmission.
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Safar JG, Giles K, Lessard P, Letessier F, Patel S, Serban A, DeArmond SJ, Prusiner SB. Conserved properties of human and bovine prion strains on transmission to guinea pigs. J Transl Med 2011; 91:1326-36. [PMID: 21727894 PMCID: PMC3164925 DOI: 10.1038/labinvest.2011.89] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The first transmissions of human prion diseases to rodents used guinea pigs (Gps, Cavia porcellus). Later, transgenic mice expressing human or chimeric human/mouse PrP replaced Gps, but the small size of the mouse limits some investigations. To investigate the fidelity of strain-specific prion transmission to Gps, we inoculated 'type 1' and 'type 2' prion strains into Gps, and we measured the incubation times and determined the strain-specified size of the unglycosylated, protease-resistant (r) PrP(Sc) fragment. Prions passaged once in Gps from cases of sporadic (s) Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker (GSS) disease caused by the P102L mutation were used, as well as human prions from a variant (v) CJD case, bovine prions from bovine spongiform encephalopathy (BSE) and mouse-passaged scrapie prions. Variant CJD and BSE prions transmitted to all the inoculated Gps with incubation times of 367 ± 4 and 436 ± 28 days, respectively. On second passage in Gps, vCJD and BSE prions caused disease in 287 ± 4 and 310 ± 4 days, whereas sCJD and GSS prions transmitted in 237 ± 4 and 279 ± 19 days, respectively. Although hamster Sc237 prions transmitted to two of three Gps after 574 and 792 days, mouse-passaged RML and 301V prion strains, the latter derived from BSE prions, failed to transmit disease to Gps. Those Gps inoculated with vCJD or BSE prions exhibited 'type 2' unglycosylated, rPrP(Sc) (19 kDa), whereas those receiving sCJD or GSS prions displayed 'type 1' prions (21 kDa), as determined by western blotting. Such strain-specific properties were maintained in Gps as well as mice expressing a chimeric human/mouse transgene. Gps may prove particularly useful in further studies of novel human prions such as those causing vCJD.
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Affiliation(s)
- Jiri G. Safar
- Institute for Neurodegenerative Diseases, University of California, San Francisco
,Department of Neurology, University of California, San Francisco
| | - Kurt Giles
- Institute for Neurodegenerative Diseases, University of California, San Francisco
,Department of Neurology, University of California, San Francisco
| | - Pierre Lessard
- Institute for Neurodegenerative Diseases, University of California, San Francisco
| | - Frederic Letessier
- Institute for Neurodegenerative Diseases, University of California, San Francisco
| | - Smita Patel
- Institute for Neurodegenerative Diseases, University of California, San Francisco
| | - Ana Serban
- Institute for Neurodegenerative Diseases, University of California, San Francisco
| | - Stephen J. DeArmond
- Institute for Neurodegenerative Diseases, University of California, San Francisco
,Department of Pathology, University of California, San Francisco
| | - Stanley B. Prusiner
- Institute for Neurodegenerative Diseases, University of California, San Francisco
,Department of Neurology, University of California, San Francisco
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Stitz L, Aguzzi A. Aerosols: an underestimated vehicle for transmission of prion diseases? Prion 2011; 5:138-41. [PMID: 21778819 DOI: 10.4161/pri.5.3.16851] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We and others have recently reported that prions can be transmitted to mice via aerosols. These reports spurred a lively public discussion on the possible public-health threats represented by prion-containing aerosols. Here we offer our view on the context in which these findings should be placed. On the one hand, the fact that nebulized prions can transmit disease cannot be taken to signify that prions are airborne under natural circumstances. On the other hand, it appears important to underscore the fact that aerosols can originate very easily in a broad variety of experimental and natural environmental conditions. Aerosols are a virtually unavoidable consequence of the handling of fluids; complete prevention of the generation of aerosols is very difficult. While prions have never been found to be transmissible via aerosols under natural conditions, it appears prudent to strive to minimize exposure to potentially prion-infected aerosols whenever the latter may arise - for example in scientific and diagnostic laboratories handling brain matter, cerebrospinal fluids, and other potentially contaminated materials, as well as abattoirs. Equally important is that prion biosafety training be focused on the control of, and protection from, prion-infected aerosols.
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Affiliation(s)
- Lothar Stitz
- Institute of Immunology, Friedrich-Loeffler-Institut, Tübingen, Germany.
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Detection of chronic wasting disease prions in salivary, urinary, and intestinal tissues of deer: potential mechanisms of prion shedding and transmission. J Virol 2011; 85:6309-18. [PMID: 21525361 DOI: 10.1128/jvi.00425-11] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Efficient horizontal transmission is a signature trait of chronic wasting disease (CWD) in cervids. Infectious prions shed into excreta appear to play a key role in this facile transmission, as has been demonstrated by bioassays of cervid and transgenic species and serial protein misfolding cyclic amplification (sPMCA). However, the source(s) of infectious prions in these body fluids has yet to be identified. In the present study, we analyzed tissues proximate to saliva, urine, and fecal production by sPMCA in an attempt to elucidate this unique aspect of CWD pathogenesis. Oropharyngeal, urogenital, and gastrointestinal tissues along with blood and obex from CWD-exposed cervids (comprising 27 animals and >350 individual samples) were analyzed and scored based on the apparent relative CWD burden. PrP(CWD)-generating activity was detected in a range of tissues and was highest in the salivary gland, urinary bladder, and distal intestinal tract. In the same assays, blood from the same animals and unseeded normal brain homogenate controls (n = 116 of 117) remained negative. The PrP-converting activity in peripheral tissues varied from 10(-11)- to 10(0)-fold of that found in brain of the same animal. Deer with highest levels of PrP(CWD) amplification in the brain had higher and more widely disseminated prion amplification in excretory tissues. Interestingly, PrP(CWD) was not demonstrable in these excretory tissues by conventional Western blotting, suggesting a low prion burden or the presence of protease-sensitive infectious prions destroyed by harsh proteolytic treatments. These findings offer unique insights into the transmission of CWD in particular and prion infection and trafficking overall.
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Crucial role for prion protein membrane anchoring in the neuroinvasion and neural spread of prion infection. J Virol 2010; 85:1484-94. [PMID: 21123371 DOI: 10.1128/jvi.02167-10] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In nature prion diseases are usually transmitted by extracerebral prion infection, but clinical disease results only after invasion of the central nervous system (CNS). Prion protein (PrP), a host-encoded glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein, is necessary for prion infection and disease. Here, we investigated the role of the anchoring of PrP on prion neuroinvasion by studying various inoculation routes in mice expressing either anchored or anchorless PrP. In control mice with anchored PrP, intracerebral or sciatic nerve inoculation resulted in rapid CNS neuroinvasion and clinical disease (154 to 156 days), and after tongue, ocular, intravenous, or intraperitoneal inoculation, CNS neuroinvasion was only slightly slower (193 to 231 days). In contrast, in anchorless PrP mice, these routes resulted in slow and infrequent CNS neuroinvasion. Only intracerebral inoculation caused brain PrPres, a protease-resistant isoform of PrP, and disease in both types of mice. Thus, anchored PrP was an essential component for the rapid neural spread and CNS neuroinvasion of prion infection.
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Abstract
While chronic wasting disease (CWD) prion transmission, entry, and trafficking remain incompletely elucidated, natural exposure of the oral and/or nasal mucous membranes seems certain. Cervids commonly sustain minor lesions on oral mucous membranes that could have an impact on susceptibility to prion infection. To explore this potential cofactor, we studied cohorts of cervid PrP transgenic mice with or without superficial abrasions on the lingual mucosa to determine whether minor oral mucosa lesions may enhance susceptibility to CWD infections. Results demonstrated that minor lingual abrasions substantially facilitate CWD transmission, revealing a cofactor that may be significant in cervids and perhaps other species.
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Seelig DM, Mason GL, Telling GC, Hoover EA. Pathogenesis of chronic wasting disease in cervidized transgenic mice. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:2785-97. [PMID: 20395435 DOI: 10.2353/ajpath.2010.090710] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chronic wasting disease (CWD) is a fatal, endemic prion disease of wild and captive cervids, including deer, elk, and moose. Typical of prion diseases, CWD is characterized by the conversion of the native, protease-sensitive protein PrP(C) to a protease-resistant isoform, denoted as PrP(RES). Here we have studied the expression of cervid PrP(C) and the pathogenesis of CWD infection in transgenic mice expressing the normal cervid prion protein (Tg[CerPrP] mice). Using tissue-based in situ immunohistochemistry protocols, we first identified cervid PrP(C) expression in the lymphoid, nervous, hemopoietic, endocrine, and certain epithelial tissues of Tg[CerPrP] mice. Tg[CerPrP] mice were then inoculated with CWD via one of four routes (intracerebral, intravenous, intraperitoneal, or oral); all groups developed spongiform encephalopathy, although the oral route required a larger infecting dose. Incubation periods were 184 +/- 13, 218 +/- 15, 200 +/- 7, and 350 +/- 27 days after inoculation, respectively. In longitudinal studies, we tracked the appearance of PrP(RES) in the brain, spleen, Peyer's patches, lymph nodes, pancreatic islets of Langerhans, bone marrow, and salivary glands of preclinical and terminal mice. In addition, we documented horizontal transmission of CWD from inoculated mice and to un-inoculated cohabitant cage-mates. This work documents the multiroute susceptibility, pathogenesis, and lateral transmission of CWD infection in Tg[CerPrP] mice, affirming this model as a robust system to study this cervid transmissible spongiform encephalopathy.
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Affiliation(s)
- Davis M Seelig
- Colorado State University, Department of Microbiology, Immunology, and Pathology, 1619 Campus Delivery, Fort Collins, CO 80523, USA
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Luhr KM, Löw P, Taraboulos A, Bergman T, Kristensson K. Prion adsorption to stainless steel is promoted by nickel and molybdenum. J Gen Virol 2009; 90:2821-2828. [PMID: 19605588 DOI: 10.1099/vir.0.012302-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Prions are infectious agents resulting from the conversion of a normal cellular protein, PrP(C), to a misfolded species, PrP(Sc). Iatrogenic transmission of prions is known from surgical procedures involving stainless steel materials. Here, it was shown that stainless steel containing nickel and molybdenum binds PrP(Sc) more efficiently and transmits infection to cells in culture to a higher degree than if these elements are not present. Furthermore, both nickel and molybdenum alone adsorbed PrP(Sc), and nickel powder could be used to extract PrP(Sc) from dilute solutions, thus providing a simple approach to concentration of PrP(Sc). The fact that nickel and molybdenum in steel alloys increased the binding affinity, and bound infectivity, of PrP(Sc) is an important issue to consider in the manufacture of surgical instruments and abattoir tools.
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Affiliation(s)
- Katarina M Luhr
- Department of Neuroscience, Retzius väg 8, Karolinska Institutet, Stockholm, Sweden
| | - Peter Löw
- Department of Neuroscience, Retzius väg 8, Karolinska Institutet, Stockholm, Sweden
| | - Albert Taraboulos
- Department of Molecular Biology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Tomas Bergman
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Krister Kristensson
- Department of Neuroscience, Retzius väg 8, Karolinska Institutet, Stockholm, Sweden
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Cardone F, Thomzig A, Schulz-Schaeffer W, Valanzano A, Sbriccoli M, Abdel-Haq H, Graziano S, Pritzkow S, Puopolo M, Brown P, Beekes M, Pocchiari M. PrPTSE in muscle-associated lymphatic tissue during the preclinical stage of mice infected orally with bovine spongiform encephalopathy. J Gen Virol 2009; 90:2563-2568. [PMID: 19535501 DOI: 10.1099/vir.0.010801-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The involvement of muscles in the pathogenesis of transmissible spongiform encephalopathies (TSEs) is irregular and unpredictable. We show that the TSE-specific protein (PrP(TSE)) is present in muscles of mice fed with a mouse-adapted strain of bovine spongiform encephalopathy as early as 100 days post-infection, corresponding to about one-third of the incubation period. The proportion of mice with PrP(TSE)-positive muscles and the number of muscles involved increased as infection progressed, but never attained more than a limited distribution, even at the clinical stage of disease. The appearance of PrP(TSE) in muscles during the preclinical stage of disease was probably due to the haematogenous/lymphatic spread of infectivity from the gastrointestinal tract to lymphatic tissues associated with muscles, whereas in symptomatic animals, the presence of PrP(TSE) in the nervous system, in neuromuscular junctions and in muscle fibres suggests a centrifugal spread from the central nervous system, as already observed in other TSE models.
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Affiliation(s)
- Franco Cardone
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Achim Thomzig
- Robert Koch-Institut (P24 - Transmissible Spongiform Encephalopathies), Nordufer 20, 13353 Berlin, Germany
| | - Walter Schulz-Schaeffer
- Prion and Dementia Research Unit, Department of Neuropathology, University Medical Center, Georg-August University Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany
| | - Angelina Valanzano
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Marco Sbriccoli
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Hanin Abdel-Haq
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Silvia Graziano
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Sandra Pritzkow
- Robert Koch-Institut (P24 - Transmissible Spongiform Encephalopathies), Nordufer 20, 13353 Berlin, Germany
| | - Maria Puopolo
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Paul Brown
- 7815 Exeter Road, Bethesda, MD 20814, USA
| | - Michael Beekes
- Robert Koch-Institut (P24 - Transmissible Spongiform Encephalopathies), Nordufer 20, 13353 Berlin, Germany
| | - Maurizio Pocchiari
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
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Role of the lymphoreticular system in prion neuroinvasion from the oral and nasal mucosa. J Virol 2009; 83:6435-45. [PMID: 19369351 DOI: 10.1128/jvi.00018-09] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prion neuroinvasion from peripheral tissues involves agent replication in the lymphoreticular system (LRS) prior to entry into the nervous system. This study investigated the role of the LRS in prion neuroinvasion from the oral and nasal mucosa in wild-type and immunodeficient mice and in hamsters infected with the HY and DY strains of the transmissible mink encephalopathy (TME) agent. Following inoculation at neural sites, all hosts were susceptible to prion disease and had evidence of prion infection in the brain, but infection of the LRS was found only in scrapie-infected wild-type mice and HY TME-infected hamsters. In the LRS replication-deficient models, prion neuroinvasion was not observed following intraperitoneal or oral inoculation. However, immunodeficient mice, which have impaired follicular dendritic cells, were susceptible to scrapie following intratongue and intranasal inoculation despite the absence of PrP(Sc) in the tongue or the nasal cavity. For DY TME, hamsters were susceptible following intratongue but not intranasal inoculation and PrP(Sc) was limited to nerve fibers of the tongue. These findings indicate that neuroinvasion from the tongue and nasal cavity can be independent of LRS infection but neuroinvasion was partially dependent on the strain of the prion agent and/or the host species. The paucity of PrP(Sc) deposition in the oral and nasal mucosa from LRS replication-deficient hosts following neuroinvasion from these tissues suggests an infection of nerve fibers that is below the threshold of PrP(Sc) detection and/or the transport of the prion agent along cranial nerves without agent replication.
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Abstract
Prion diseases are emerging infectious disorders that affect several mammalian species including humans. The transmissible agent is comprised of PrP(Sc), a misfolded isoform of the normal host-encoded prion protein PrP(C). Immunodetection of PrP(Sc) is often utilized for prion disease diagnosis and tracking spread of the infectious agent through the host. We have developed a rapid, high-throughput 96-well immunoassay, which is specific for the detection of PrP(Sc). This assay has PrP(Sc) detection limits similar to western blot and is advantageous because of its comparatively shorter running time, smaller start-up and operation costs and large sample capacity.
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Affiliation(s)
- Michelle L Kramer
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE 68178, USA
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Race B, Meade-White K, Oldstone MBA, Race R, Chesebro B. Detection of prion infectivity in fat tissues of scrapie-infected mice. PLoS Pathog 2008; 4:e1000232. [PMID: 19057664 PMCID: PMC2585054 DOI: 10.1371/journal.ppat.1000232] [Citation(s) in RCA: 28] [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: 08/12/2008] [Accepted: 11/05/2008] [Indexed: 02/04/2023] Open
Abstract
Distribution of prion infectivity in organs and tissues is important in understanding prion disease pathogenesis and designing strategies to prevent prion infection in animals and humans. Transmission of prion disease from cattle to humans resulted in banning human consumption of ruminant nervous system and certain other tissues. In the present study, we surveyed tissue distribution of prion infectivity in mice with prion disease. We show for the first time detection of infectivity in white and brown fat. Since high amounts of ruminant fat are consumed by humans and also incorporated into animal feed, fat-containing tissues may pose a previously unappreciated hazard for spread of prion infection. Prion diseases, also known as transmissible spongiform encephalopathies, are infectious progressive fatal neurodegenerative diseases which affect humans as well as wild and domestic animals. Distribution of prion infectivity in organs and tissues is important in understanding prion disease pathogenesis and designing strategies to prevent prion infection in animals and humans. We show for the first time the presence of prion infectivity in white fat and brown fat tissues of mice with prion disease. Our results suggest that fat tissues of domestic or wild animals infected with prions may pose an unappreciated hazard for spread of infection to humans or domestic animals. The presence of prion infectivity in fat suggests that additional consideration may be required to eliminate from the food chain any fat from ruminants suspected of exposure to or infection with prions. Thus, this finding has implications for public health, food safety, and prion disease prevention strategies.
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Affiliation(s)
- Brent Race
- Laboratory of Persistent Virus Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Kimberly Meade-White
- Laboratory of Persistent Virus Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Michael B. A. Oldstone
- Department of Immunology and Microbial Science, The Scripps Research Institute, LaJolla, California, United States of America
| | - Richard Race
- Laboratory of Persistent Virus Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Bruce Chesebro
- Laboratory of Persistent Virus Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
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Zhu X, Matoba S, Hara K, Ano Y, Kobayashi SI, Tsunekawa N, Kanai Y, Manabe N, Onodera T, Kurohmaru M. Ratio of peripheral nervous tissues in tongues, skeletal muscles and intestines in cows. Okajimas Folia Anat Jpn 2008; 85:73-77. [PMID: 18975615 DOI: 10.2535/ofaj.85.73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
It is suggested that pathogenic prion protein (PrP(sc) may accumulate in peripheral nervous tissues in addition to the specified-risk materials. To assess the risk of PrP(sc) accumulation in peripheral tissues, the present study was designed to study the ratio of peripheral nervous tissues in tongues, skeletal muscles and intestines in 2-week- and 59-month-old cows. The nervous tissues could be detected by immunohistochemistry using antibody Neurofilament 150. After immunostaining with Neurofilament 150, the photographs taken from each section were applied for Scion Image software. Then, the ratio of nervous tissues in tongues, skeletal muscles and intestines were calculated. The highest ratio of peripheral nervous tissues was observed in intestines, the second highest ratio was found in tongues, and the lowest ratio was recognized in skeletal muscles in both 2-week- and 59-month-old cows. The ratio of nervous tissues in intestines was approximately 2.5 fold and 10 fold, compared to that in skeletal muscles in 2-week- and 59-month-old cows, respectively. These results suggest that intestines and tongues may have a higher risk of PrP(sc) accumulation, compared to skeletal muscles.
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Affiliation(s)
- XiaoBo Zhu
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
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29
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Walker J, Dickinson J, Sutton J, Marsh P, Raven N. Implications for Creutzfeldt-Jakob Disease (CJD) in Dentistry: a Review of Current Knowledge. J Dent Res 2008; 87:511-9. [DOI: 10.1177/154405910808700613] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This review explores our current understanding of the risks of (variant) Creutzfeldt-Jakob disease transmission via dental practice, and whether they merit the rigorous enforcement of improved standards of instrument cleaning and decontamination. The recognition of prions as novel infectious agents in humans has caused significant concern among the public and medical professionals alike. Creutzfeldt-Jakob disease (CJD) in humans has been shown to be transmissible via several routes, including transplantation, contaminated medical products, and via neurosurgery. While the likelihood of transmission via dentistry is undoubtedly very low, this may be amplified considerably by unknown risk factors, such as disease prevalence (particularly in the UK), altered tissue distribution of vCJD, and the failure of decontamination processes to address the inactivation of prions adequately. Since current diagnostic techniques are unable to detect PrPSc in human dental tissues, there is limited evidence for the presence of infectivity. Given these uncertainties, the control of risk by reinforced and improved decontamination practices seems the most appropriate response.
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Affiliation(s)
- J.T. Walker
- TSE Research Group, Centre for Emergency Preparedness and Response, HPA, Porton Down, Salisbury SP4 0JG, UK; and
- Leeds Dental Institute, Leeds, LS2 9LU, UK
| | - J. Dickinson
- TSE Research Group, Centre for Emergency Preparedness and Response, HPA, Porton Down, Salisbury SP4 0JG, UK; and
- Leeds Dental Institute, Leeds, LS2 9LU, UK
| | - J.M. Sutton
- TSE Research Group, Centre for Emergency Preparedness and Response, HPA, Porton Down, Salisbury SP4 0JG, UK; and
- Leeds Dental Institute, Leeds, LS2 9LU, UK
| | - P.D. Marsh
- TSE Research Group, Centre for Emergency Preparedness and Response, HPA, Porton Down, Salisbury SP4 0JG, UK; and
- Leeds Dental Institute, Leeds, LS2 9LU, UK
| | - N.D.H. Raven
- TSE Research Group, Centre for Emergency Preparedness and Response, HPA, Porton Down, Salisbury SP4 0JG, UK; and
- Leeds Dental Institute, Leeds, LS2 9LU, UK
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30
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Hamir AN, Kunkle RA, Bulgin MS, Rohwer RG, Gregori L, Richt JA. Experimental transmission of scrapie agent to susceptible sheep by intralingual or intracerebral inoculation. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2008; 72:63-67. [PMID: 18214164 PMCID: PMC2117369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 06/25/2007] [Indexed: 05/25/2023]
Abstract
Scrapie, a transmissible spongiform encephalopathy (TSE), is a naturally occurring fatal neurodegenerative disease of sheep and goats. This study documents survival periods, pathological findings, and the presence of abnormal prion protein (PrP(Sc)) in genetically susceptible sheep inoculated with scrapie agent. Suffolk lambs (AA/RR/QQ at codons 136, 154, and 171, respectively) aged 4 mo were injected by the intralingual (IL) or intracerebral (IC) route with an inoculum prepared from a pool of scrapie-affected US sheep brains. The animals were euthanized when advanced clinical signs of scrapie were observed. Spongiform lesions in the brain and PrPsc deposits in the central nervous system (CNS) and lymphoid tissues were detected by immunohistochemical and Western blot (WB) testing in all the sheep with clinical prion disease. The mean survival period was 18.3 mo for the sheep inoculated by the IL route and 17.6 mo for those inoculated by the IC route. Since the IC method is occasionally associated with anesthesia-induced complications, intracranial hematoma, and CNS infections, and the IL method is very efficient, it may be more humane to use the latter. However, before this method can be recommended for inoculation of TSE agents, research needs to show that other TSE agents can also transmit disease via the tongue.
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Affiliation(s)
- Amir N Hamir
- National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, 2300 Dayton Avenue, PO Box 70, Ames, Iowa 50010, USA.
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31
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Cleanability of dental instruments – implications of residual protein and risks from Creutzfeldt-Jakob disease. Br Dent J 2007; 203:395-401. [DOI: 10.1038/bdj.2007.893] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2007] [Indexed: 11/08/2022]
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32
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Hamir AN, Miller JM, Kunkle RA, Hall SM, Richt JA. Susceptibility of cattle to first-passage intracerebral inoculation with chronic wasting disease agent from white-tailed deer. Vet Pathol 2007; 44:487-93. [PMID: 17606510 DOI: 10.1354/vp.44-4-487] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fourteen, 3-month-old calves were intracerebrally inoculated with the agent of chronic wasting disease (CWD) from white-tailed deer (CWDwtd) to compare the clinical signs and neuropathologic findings with those of certain other transmissible spongiform encephalopathies (TSE, prion diseases) that have been shown to be experimentally transmissible to cattle (sheep scrapie, CWD of mule deer [CWDmd], bovine spongiform encephalopathy [BSE], and transmissible mink encephalopathy). Two uninoculated calves served as controls. Within 26 months postinoculation (MPI), 12 inoculated calves had lost considerable weight and eventually became recumbent. Of the 12 inoculated calves, 11 (92%) developed clinical signs. Although spongiform encephalopathy (SE) was not observed, abnormal prion protein (PrPd) was detected by immunohistochemistry (IHC) and Western blot (WB) in central nervous system tissues. The absence of SE with presence of PrPd has also been observed when other TSE agents (scrapie and CWDmd) were similarly inoculated into cattle. The IHC and WB findings suggest that the diagnostic techniques currently used to confirm BSE would detect CWDwtd in cattle, should it occur naturally. Also, the absence of SE and a distinctive IHC pattern of CWDwtd and CWDmd in cattle suggests that it should be possible to distinguish these conditions from other TSEs that have been experimentally transmitted to cattle.
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Affiliation(s)
- A N Hamir
- National Animal Disease Center, ARS, USDA, Ames, IA 50010, USA.
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Novakofski J, Brewer MS, Mateus-Pinilla N, Killefer J, McCusker RH. Prion biology relevant to bovine spongiform encephalopathy. J Anim Sci 2007; 83:1455-76. [PMID: 15890824 DOI: 10.2527/2005.8361455x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bovine spongiform encephalopathy (BSE) and chronic wasting disease (CWD) of deer and elk are a threat to agriculture and natural resources, as well as a human health concern. Both diseases are transmissible spongiform encephalopathies (TSE), or prion diseases, caused by autocatalytic conversion of endogenously encoded prion protein (PrP) to an abnormal, neurotoxic conformation designated PrPsc. Most mammalian species are susceptible to TSE, which, despite a range of species-linked names, is caused by a single highly conserved protein, with no apparent normal function. In the simplest sense, TSE transmission can occur because PrPsc is resistant to both endogenous and environmental proteinases, although many details remain unclear. Questions about the transmission of TSE are central to practical issues such as livestock testing, access to international livestock markets, and wildlife management strategies, as well as intangible issues such as consumer confidence in the safety of the meat supply. The majority of BSE cases seem to have been transmitted by feed containing meat and bone meal from infected animals. In the United Kingdom, there was a dramatic decrease in BSE cases after neural tissue and, later, all ruminant tissues were banned from ruminant feed. However, probably because of heightened awareness and widespread testing, there is growing evidence that new variants of BSE are arising "spontaneously," suggesting ongoing surveillance will continue to find infected animals. Interspecies transmission is inefficient and depends on exposure, sequence homology, TSE donor strain, genetic polymorphism of the host, and architecture of the visceral nerves if exposure is by an oral route. Considering the low probability of interspecies transmission, the low efficiency of oral transmission, and the low prion levels in nonnervous tissues, consumption of conventional animal products represents minimal risk. However, detection of rare events is challenging, and TSE literature is characterized by subsequently unsupported claims of species barriers or absolute tissue safety. This review presents an overview of TSE and summarizes recent research on pathogenesis and transmission.
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Affiliation(s)
- J Novakofski
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, IL 61801-4737, USA.
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Beekes M, McBride PA. The spread of prions through the body in naturally acquired transmissible spongiform encephalopathies. FEBS J 2007; 274:588-605. [PMID: 17288548 DOI: 10.1111/j.1742-4658.2007.05631.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Transmissible spongiform encephalopathies are fatal neurodegenerative diseases that are caused by unconventional pathogens and affect the central nervous system of animals and humans. Several different forms of these diseases result from natural infection (i.e. exposure to transmissible spongiform encephalopathy agents or prions, present in the natural environment of the respective host). This holds true also for scrapie in sheep, bovine spongiform encephalopathy in cattle, chronic wasting disease in elk and deer, or variant Creutzfeldt-Jakob disease in humans, all of which are assumed to originate predominantly from peroral prion infection. This article intends to provide an overview of the current state of knowledge on the spread of scrapie, chronic wasting disease, bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease agents through the body in naturally affected hosts, and in model animals experimentally challenged via the alimentary tract. Special attention is given to the tissue components and spreading pathways involved in the key stages of prion routing through the body, such as intestinal uptake, neuroinvasion of nerves and the central nervous system, and centrifugal spread from the brain and spinal cord to peripheral sites (e.g. sensory ganglia or muscles). The elucidation of the pathways and mechanisms by which prions invade a host and spread through the organism can contribute to efficient infection control strategies and the improvement of transmissible spongiform encephalopathy diagnostics. It may also help to identify prophylactic or therapeutic approaches that would impede naturally acquired transmissible spongiform encephalopathy infections.
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Affiliation(s)
- Michael Beekes
- Robert Koch-Institut (P24 - Transmissible Spongiforme Enzephalopathien), Berlin, Germany.
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Trifilo MJ, Ying G, Teng C, Oldstone MB. Chronic wasting disease of deer and elk in transgenic mice: oral transmission and pathobiology. Virology 2007; 365:136-43. [PMID: 17451773 PMCID: PMC1950321 DOI: 10.1016/j.virol.2007.03.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 02/21/2007] [Accepted: 03/15/2007] [Indexed: 01/05/2023]
Abstract
To study the pathogenesis of chronic wasting disease (CWD) in deer and elk, transgenic (tg) mice were generated that expressed the prion protein (PrP) of deer containing a glycine at amino acid (aa) 96 and a serine at aa 225 under transcriptional control of the murine PrP promoter. This construct was introduced into murine PrP-deficient mice. As anticipated, neither non-tg mice nor PrP ko mice were susceptible when inoculated intracerebrally (i.c.) or orally with CWD brain material (scrapie pool from six mule deer) and followed for 600+ days (dpi). Deer PrP tg mice were not susceptible to i.c. inoculation with murine scrapie. In contrast, a fatal neurologic disease occurred accompanied by conversion of deer PrPsen to PrPres by western blot and immunohistochemistry after either i.c. inoculation with CWD brain into two lines of tg mice studied (312+32 dpi [mean+2 standard errors] for the heterozygous tg line 33, 275+46 dpi for the heterozygous tg line 39 and 210 dpi for the homozygous tg line 33) or after oral inoculation (381+55 dpi for the homozygous tg line 33 and 370+26 dpi for the homozygous tg line 39). Kinetically, following oral inoculation of CWD brain, PrPres was observed by day 200 when mice were clinically healthy in the posterior surface of the dorsum of the tongue primarily in serous and mucous glands, in the intestines, in large cells at the splenic marginal zone that anatomically resembled follicular dendritic cells and macrophages and in the olfactory bulb and brain stem but did not occur in the cerebellum, cerebral cortex or hippocampus or in hearts, lungs and livers of infected mice. After 350 days when mice become clinically ill the cerebellum, cerebral cortex and hippocampus became positive for PrPres and displayed massive spongiosis, neuronal drop out, gliosis and florid plaques.
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Affiliation(s)
- Matthew J. Trifilo
- Viral-Immunobiology Laboratory, Molecular and Integrative Neurosciences Department, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ge Ying
- Viral-Immunobiology Laboratory, Molecular and Integrative Neurosciences Department, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Chao Teng
- Viral-Immunobiology Laboratory, Molecular and Integrative Neurosciences Department, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Michael B.A. Oldstone
- Viral-Immunobiology Laboratory, Molecular and Integrative Neurosciences Department, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
- Department of Infectology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
- *Corresponding author. Fax: 858-784-9981. E-mail address: (M.B.A. Oldstone)
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Abstract
The prion agent has been detected in skeletal muscle of humans and animals with prion diseases. Here we report scrapie infection of murine C2C12 myoblasts and myotubes in vitro following coculture with a scrapie-infected murine neuroblastoma (N2A) cell line but not following incubation with a scrapie-infected nonneuronal cell line or a scrapie brain homogenate. Terminal differentiation of scrapie-infected C2C12 myoblasts into myotubes resulted in an increase in the expression of the disease-specific prion protein, PrP(Sc). The amount of scrapie infectivity or PrP(Sc) in C2C12 myotubes was comparable to the levels found in scrapie-infected N2A cells, indicating that a high level of infection was established in muscle cells. Subclones of scrapie-infected C2C12 cells produced high levels of PrP(Sc) in myotubes, and the C-terminal C2 polypeptide fragment of PrP(Sc) was found based on deglycosylation and PrP(Sc)-specific immunoprecipitation of cell lysates. This is the first report of a stable prion infection in muscle cells in vitro and of a long-term prion infection in a nondividing, differentiated peripheral cell type in culture. These in vitro studies also suggest that in vivo prion infection of skeletal muscle requires contact with prion-infected neurons or, possibly, nerve terminals.
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Affiliation(s)
- Wendy M Dlakic
- Department of Veterinary Molecular Biology, Montana State University, P.O. Box 173610, Bozeman, MT 59717, USA
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37
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Everington D, Smith AJ, Ward HJT, Letters S, Will RG, Bagg J. Dental treatment and risk of variant CJD--a case control study. Br Dent J 2007; 202:E19; discussion 470-1. [PMID: 17299423 DOI: 10.1038/bdj.2007.126] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2006] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Knowledge of risk factors for variant CJD (vCJD) remains limited, but transmission of prion proteins via re-useable medical devices, including dental instruments, or enhanced susceptibility following trauma to the oral cavity is a concern. This study aimed to identify whether previous dental treatment is a risk factor for development of vCJD. DESIGN Case control study. METHODS Risk factor questionnaires completed by interview with relatives of 130 vCJD patients and with relatives of 66 community and 53 hospital controls were examined by a dental surgeon. Responses regarding dental treatments were analysed. RESULTS We did not find a statistically significant excess of risk of vCJD associated with dental treatments with the exception of extractions in an unmatched analysis of vCJD cases with community controls (p = 0.02). However, this result may be explained by multiple testing. CONCLUSIONS This is the first published study to date to examine potential links between vCJD and dental treatment. There was no convincing evidence found of an increased risk of variant CJD associated with reported dental treatment. However, the power of the study is restricted by the number of vCJD cases to date and does not preclude the possibility that some cases have resulted from secondary transmission via dental procedures. Due to the limitations of the data available, more detailed analyses of dental records are required to fully exclude the possibility of transmission via dental treatment.
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Affiliation(s)
- D Everington
- National Creutzfeldt-Jakob Disease Surveillance Unit, The University of Edinburgh, Western General Hospital, Edinburgh, UK
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Jewell JE, Brown J, Kreeger T, Williams ES. Prion protein in cardiac muscle of elk (Cervus elaphus nelsoni) and white-tailed deer (Odocoileus virginianus) infected with chronic wasting disease. J Gen Virol 2006; 87:3443-3450. [PMID: 17030881 DOI: 10.1099/vir.0.81777-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
To investigate the possible presence of disease-associated prion protein (PrP(d)) in striated muscle of chronic wasting disease (CWD)-affected cervids, samples of diaphragm, tongue, heart and three appendicular skeletal muscles from mule deer (Odocoileus hemionus), white-tailed deer (Odocoileus virginianus), elk (Cervus elaphus nelsoni) and moose (Alces alces shirasi) were examined by ELISA, Western immunoblot and immunohistochemistry (IHC). PrP(d) was detected in samples of heart muscle from seven of 16 CWD-infected white-tailed deer, including one free-ranging deer, and in 12 of 17 CWD-infected elk, but not in any of 13 mule deer samples, nor in the single CWD-infected moose. For white-tailed deer, PrP(d) was detected by Western blot at multiple sites throughout the heart; IHC results on ventricular sections of both elk and white-tailed deer showed positive staining in cardiac myocytes, but not in conduction tissues or nerve ganglia. Levels of PrP(d) in cardiac tissues were estimated from Western blot band intensity to be lower than levels found in brain tissue. PrP(d) was not detected in diaphragm, triceps brachii, semitendinosus, latissiumus dorsi or tongue muscles for any of the study subjects. This is the first report of PrP(d) in cardiac tissue from transmissible spongiform encephalopathy-infected ruminants in the human food chain and the first demonstration by immunological assays of PrP(d) in any striated muscle of CWD-infected cervids.
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Affiliation(s)
- Jean E Jewell
- Department of Veterinary Sciences, University of Wyoming, Wyoming State Veterinary Laboratory (WSVL), 1174 Snowy Range Road, Laramie, WY 82070, USA
| | - Jeremy Brown
- Department of Veterinary Sciences, University of Wyoming, Wyoming State Veterinary Laboratory (WSVL), 1174 Snowy Range Road, Laramie, WY 82070, USA
| | - Terry Kreeger
- Veterinary Services Branch, Wyoming Game and Fish Department (WGFD), Wheatland, WY 82201, USA
| | - Elizabeth S Williams
- Department of Veterinary Sciences, University of Wyoming, Wyoming State Veterinary Laboratory (WSVL), 1174 Snowy Range Road, Laramie, WY 82070, USA
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Hamir AN, Kunkle RA, Miller JM, Greenlee JJ, Richt JA. Experimental second passage of chronic wasting disease (CWD(mule deer)) agent to cattle. J Comp Pathol 2006; 134:63-9. [PMID: 16423572 DOI: 10.1016/j.jcpa.2005.07.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Accepted: 07/23/2005] [Indexed: 10/25/2022]
Abstract
To compare clinicopathological findings in first and second passage chronic wasting disease (CWD(mule deer)) in cattle, six calves were inoculated intracerebrally with brain tissue derived from a first-passage CWD-affected calf in an earlier experiment. Two uninoculated calves served as controls. The inoculated animals began to lose both appetite and weight 10-12 months later, and five subsequently developed clinical signs of central nervous system (CNS) abnormality. By 16.5 months, all cattle had been subjected to euthanasia because of poor prognosis. None of the animals showed microscopical lesions of spongiform encephalopathy (SE) but PrP(res) was detected in their CNS tissues by immunohistochemistry (IHC) and rapid Western blot (WB) techniques. Thus, intracerebrally inoculated cattle not only amplified CWD PrP(res) from mule deer but also developed clinical CNS signs in the absence of SE lesions. This situation has also been shown to occur in cattle inoculated with the scrapie agent. The study confirmed that the diagnostic techniques currently used for diagnosis of bovine spongiform encephalopathy (BSE) in the US would detect CWD in cattle, should it occur naturally. Furthermore, it raised the possibility of distinguishing CWD from BSE in cattle, due to the absence of neuropathological lesions and to a distinctive multifocal distribution of PrP(res), as demonstrated by IHC which, in this study, appeared to be more sensitive than the WB technique.
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Affiliation(s)
- A N Hamir
- Agricultural Research Service, United States Department of Agriculture, National Animal Disease Center, 2300 Dayton Avenue, P.O. Box 70, Ames, IA 50010, USA
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40
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Corona C, Casalone C, Acutis PL, Crescio MI, Martucci F, Iulini B, Florio CL, Gazzuola P, Perfetti G, Bona C, Ru G, Caramelli M. Detection of Pathological Prion Protein in the Tongue of Sheep Infected with Naturally Occurring Scrapie. Vet Res Commun 2006. [DOI: 10.1007/s11259-006-0050-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Abstract
Centrifugal spread of the prion agent to peripheral tissues is postulated to occur by axonal transport along nerve fibers. This study investigated the distribution of the pathological isoform of the protein (PrP(Sc)) in the tongues and nasal cavities of hamsters following intracerebral inoculation of the HY strain of the transmissible mink encephalopathy (TME) agent. We report that PrP(Sc) deposition was found in the lamina propria, taste buds, and stratified squamous epithelium of fungiform papillae in the tongue, as well as in skeletal muscle cells. Using laser scanning confocal microscopy, PrP(Sc) was localized to nerve fibers in each of these structures in the tongue, neuroepithelial taste cells of the taste bud, and, possibly, epithelial cells. This PrP(Sc) distribution was consistent with a spread of HY TME agent along both somatosensory and gustatory cranial nerves to the tongue and suggests subsequent synaptic spread to taste cells and epithelial cells via peripheral synapses. In the nasal cavity, PrP(Sc) accumulation was found in the olfactory and vomeronasal epithelium, where its location was consistent with a distribution in cell bodies and apical dendrites of the sensory neurons. Prion spread to these sites is consistent with transport via the olfactory nerve fibers that descend from the olfactory bulb. Our data suggest that epithelial cells, neuroepithelial taste cells, or olfactory sensory neurons at chemosensory mucosal surfaces, which undergo normal turnover, infected with the prion agent could be shed and play a role in the horizontal transmission of animal prion diseases.
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Affiliation(s)
- Crista DeJoia
- Department of Veterinary Molecular Biology, P.O. Box 173610, Montana State University, Bozeman, Montana 59717, USA
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42
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Thomzig A, Cardone F, Krüger D, Pocchiari M, Brown P, Beekes M. Pathological prion protein in muscles of hamsters and mice infected with rodent-adapted BSE or vCJD. J Gen Virol 2006; 87:251-254. [PMID: 16361438 DOI: 10.1099/vir.0.81277-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recently, pathological prion protein (PrP(TSE)) was detected in muscle from sheep infected with scrapie, the archetype of transmissible spongiform encephalopathies (TSEs). This finding has highlighted the question of whether mammalian muscle may potentially also provide a reservoir for TSE agents related to bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob Disease (vCJD). Here, results are reported from studies in hamsters and mice that provide direct experimental evidence, for the first time, of BSE- and vCJD-associated PrP(TSE) deposition in muscles. Our findings emphasize the need for further assessment of possible public-health risks from TSE involvement of skeletal muscle.
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Affiliation(s)
- Achim Thomzig
- Robert Koch-Institut (P24 - Transmissible Spongiform Encephalopathies), Nordufer 20, 13353 Berlin, Germany
| | - Franco Cardone
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Dominique Krüger
- Robert Koch-Institut (P24 - Transmissible Spongiform Encephalopathies), Nordufer 20, 13353 Berlin, Germany
| | - Maurizio Pocchiari
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Paul Brown
- 7815 Exeter Road, Bethesda, MD 20814, USA
| | - Michael Beekes
- Robert Koch-Institut (P24 - Transmissible Spongiform Encephalopathies), Nordufer 20, 13353 Berlin, Germany
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Herzog C, Rivière J, Lescoutra-Etchegaray N, Charbonnier A, Leblanc V, Salès N, Deslys JP, Lasmézas CI. PrPTSE distribution in a primate model of variant, sporadic, and iatrogenic Creutzfeldt-Jakob disease. J Virol 2006; 79:14339-45. [PMID: 16254368 PMCID: PMC1280201 DOI: 10.1128/jvi.79.22.14339-14345.2005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human prion diseases, such as Creutzfeldt-Jakob disease (CJD), are neurodegenerative and fatal. Sporadic CJD (sCJD) can be transmitted between humans through medical procedures involving highly infected organs, such as the central nervous system. However, in variant CJD (vCJD), which is due to human contamination with the bovine spongiform encephalopathy (BSE) agent, lymphoreticular tissue also harbors the transmissible spongiform encephalopathy-associated prion protein (PrP(TSE)), which poses a particularly acute risk for iatrogenic transmission. Two blood transfusion-related cases are already documented. In addition, the recent observation of PrP(TSE) in spleen and muscle in sCJD raised the possibility that peripheral PrP(TSE) is not limited to vCJD cases. We aimed to clarify the peripheral pathogenesis of human TSEs by using a nonhuman primate model which mimics human diseases. A highly sensitive enzyme-linked immunosorbent assay was adapted to the detection of extraneural PrP(TSE). We show that affected organs can be divided into two groups. The first is peripheral organs accumulating large amounts of PrP(TSE), which represent a high risk of iatrogenic transmission. This category comprises only lymphoreticular organs in the vCJD/BSE model. The second is organs with small amounts of PrP(TSE) associated with nervous structures. These are the muscles, adrenal glands, and enteric nervous system in the sporadic, iatrogenic, and variant CJD models. In contrast to the first set of organs, this low level of tissue contamination is not strain restricted and seems to be linked to secondary centrifugal spread of the agent through nerves. It might represent a risk for iatrogenic transmission, formerly underestimated despite previous reports of low rates of transmission from peripheral organs of humans to nonhuman primates (5, 10). This study provides an additional experimental basis for the classification of human organs into different risk categories and a rational re-evaluation of current risk management measures.
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Affiliation(s)
- Christian Herzog
- Commissariat à l'Energie Atomique, Département de Recherche Médicale, BP6, 92265 Fontenay-aux-Roses, France
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Niku M, Ekman A, Pessa-Morikawa T, Iivanainen A. Identification of major cell types in paraffin sections of bovine tissues. BMC Vet Res 2006; 2:5. [PMID: 16441877 PMCID: PMC1402288 DOI: 10.1186/1746-6148-2-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Accepted: 01/27/2006] [Indexed: 11/25/2022] Open
Abstract
Background Identification of cell types in bovine tissue sections is complicated by the limited availability of anti-bovine antibodies, and by antigen retrieval treatments required for formalin-fixed tissue samples. We have evaluated an antibody and lectin panel for identifying major cell types in paraffin-embedded bovine tissue sections, and report optimized pretreatments for these markers. Results We selected 31 useful antibodies and lectins which can be used to identify cell types of epithelia, connective tissue, muscle, and nervous tissue, as well as cell proliferation and apoptosis. Conclusion The panel of markers allows the identification of all major cell types in paraffin-embedded cattle tissue sections by immunohistochemistry or lectin histochemistry. Heat-induced epitope retrieval methods are required for most antibodies.
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Affiliation(s)
- Mikael Niku
- Department of Basic Veterinary Sciences, University of Helsinki, Helsinki, Finland
| | - Anna Ekman
- Department of Basic Veterinary Sciences, University of Helsinki, Helsinki, Finland
| | - Tiina Pessa-Morikawa
- Department of Basic Veterinary Sciences, University of Helsinki, Helsinki, Finland
| | - Antti Iivanainen
- Department of Basic Veterinary Sciences, University of Helsinki, Helsinki, Finland
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Abstract
Chronic wasting disease (CWD) is a unique transmissible spongiform encephalopathy (TSE) of mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), and Rocky Mountain elk (Cervus elaphus nelsoni). The natural history of CWD is incompletely understood, but it differs from scrapie and bovine spongiform encephalopathy (BSE) by virtue of its occurrence in nondomestic and free-ranging species. CWD has many features in common with scrapie, including early widespread distribution of disease-associated prion protein (PrP(d)) in lymphoid tissues, with later involvement of central nervous system (CNS) and peripheral tissues. This distribution likely contributes to apparent efficiency of horizontal transmission and, in this, is similar to scrapie and differs from BSE. Clinical features and lesions of CWD are qualitatively similar to the other animal TSEs. Microscopically, marked spongiform lesions occur in the central nervous system (CNS) after a prolonged incubation period and variable course of clinical disease. During incubation, PrP(d) can be identified in tissues by antibody-based detection systems. Although CWD can be transmitted by intracerebral inoculation to cattle, sheep, and goats, ongoing studies have not demonstrated that domestic livestock are susceptible via oral exposure, the presumed natural route of exposure to TSEs. Surveillance efforts for CWD in captive and free-ranging cervids will continue in concert with similar activities for scrapie and BSE. Eradication of CWD in farmed cervids is the goal of state, federal, and industry programs, but eradication of CWD from free-ranging populations of cervids is unlikely with currently available management techniques.
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Affiliation(s)
- E S Williams
- Department of Veterinary Sciences, University of Wtoming, Laramie, USA
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Bartz JC, Dejoia C, Tucker T, Kincaid AE, Bessen RA. Extraneural prion neuroinvasion without lymphoreticular system infection. J Virol 2005; 79:11858-63. [PMID: 16140762 PMCID: PMC1212615 DOI: 10.1128/jvi.79.18.11858-11863.2005] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
While prion infection of the lymphoreticular system (LRS) is necessary for neuroinvasion in many prion diseases, in bovine spongiform encephalopathy and atypical cases of sheep scrapie there is evidence to challenge that LRS infection is required for neuroinvasion. Here we investigated the role of prion infection of LRS tissues in neuroinvasion following extraneural inoculation with the HY and DY strains of the transmissible mink encephalopathy (TME) agent. DY TME agent infectivity was not detected in spleen or lymph nodes following intraperitoneal inoculation and clinical disease was not observed following inoculation into the peritoneum or lymph nodes, or after oral ingestion. In contrast, inoculation of the HY TME agent by each of these peripheral routes resulted in replication in the spleen and lymph nodes and induced clinical disease. To clarify the role of the LRS in neuroinvasion, the HY and DY TME agents were also inoculated into the tongue because it is densely innervated and lesions on the tongue, which are common in ruminants, increase the susceptibility of hamsters to experimental prion disease. Following intratongue inoculation, the DY TME agent caused prion disease and was detected in both the tongue and brainstem nuclei that innervate the tongue, but the prion protein PrP(Sc) was not detected in the spleen or lymph nodes. These findings indicate that the DY TME agent can spread from the tongue to the brain along cranial nerves and neuroinvasion does not require agent replication in the LRS. These studies provide support for prion neuroinvasion from highly innervated peripheral tissues in the absence of LRS infection in natural prion diseases of livestock.
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Affiliation(s)
- Jason C Bartz
- Department of Medical Microbiology & Immunology, Creighton University, Omaha, Nebraska 68178, USA
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Casalone C, Corona C, Crescio MI, Martucci F, Mazza M, Ru G, Bozzetta E, Acutis PL, Caramelli M. Pathological prion protein in the tongues of sheep infected with naturally occurring scrapie. J Virol 2005; 79:5847-9. [PMID: 15827199 PMCID: PMC1082725 DOI: 10.1128/jvi.79.9.5847-5849.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tongue involvement by prion spreading was shown to be a common outcome after oral or intracranial experimental challenge with scrapie and transmissible mink encephalopathy sources in rodent models. It is also known that bovine spongiform encephalopathy, which is pathogenic for humans, is experimentally transmissible to sheep and can lead to a disease indistinguishable from scrapie. A recent European Food Safety Authority opinion recommended research into PrPsc accumulation in the tongues of ruminants. We report on the detection of PrPsc in the tongues of seven scrapie-infected sheep by immunohistochemistry and Western blotting.
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Affiliation(s)
- Cristina Casalone
- CEA-IZS Piemonte, Liguria e Valle d'Aosta, Via Bologna, 148 Turin 10154, Italy
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Abstract
PURPOSE OF REVIEW Prion diseases are transmissible fatal neurodegenerative disorders in which infectivity is associated with the accumulation of PrP(Sc), a disease-related isoform of normal cellular prion protein. The recent emergence of variant Creutzfeldt-Jakob disease has led to major public health concerns, and the need for the development of effective treatments. As PrP(Sc) is associated both with pathology and infectivity, therapeutic approaches to date have largely aimed at preventing its accumulation, but this strategy has produced only modest results in animal models. The link between PrP(Sc) and neurotoxicity is unclear, and alternative pathological processes need to be considered. Here we focus on the latest progress in therapeutic strategies and potential mechanisms of prion neurotoxicity. RECENT FINDINGS Passive immunisation with anti-prion protein antibodies prevents peripheral prion replication and blocks progression to clinical disease in peripherally infected mice. A new approach, in which neuronal cellular prion protein is depleted in mice with established neuroinvasive prion infection, prevents the onset of clinical disease, blocks neuronal cell loss and reverses early spongiform pathology. This dramatic protective effect occurs despite the continued build-up of extraneuronal PrP(Sc) and continued replication of prion infectivity, effectively producing a sub-clinical state. SUMMARY New insights into the mechanisms of neurotoxicity in prion diseases support the concept that PrP(Sc) itself is not directly neurotoxic. They suggest that neuronal prion propagation results in the production of a toxic intermediate or depletion of a key constituent. Prevention of the formation of such a species rather than PrP(Sc) accumulation itself is a clear target for prion therapeutics.
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Affiliation(s)
- Giovanna Mallucci
- MRC Prion Unit and Department of Neurodegenerative Disease, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
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