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Mabbott NA, Bradford BM, Pal R, Young R, Donaldson DS. The Effects of Immune System Modulation on Prion Disease Susceptibility and Pathogenesis. Int J Mol Sci 2020; 21:E7299. [PMID: 33023255 PMCID: PMC7582561 DOI: 10.3390/ijms21197299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 09/25/2020] [Accepted: 09/29/2020] [Indexed: 12/17/2022] Open
Abstract
Prion diseases are a unique group of infectious chronic neurodegenerative disorders to which there are no cures. Although prion infections do not stimulate adaptive immune responses in infected individuals, the actions of certain immune cell populations can have a significant impact on disease pathogenesis. After infection, the targeting of peripherally-acquired prions to specific immune cells in the secondary lymphoid organs (SLO), such as the lymph nodes and spleen, is essential for the efficient transmission of disease to the brain. Once the prions reach the brain, interactions with other immune cell populations can provide either host protection or accelerate the neurodegeneration. In this review, we provide a detailed account of how factors such as inflammation, ageing and pathogen co-infection can affect prion disease pathogenesis and susceptibility. For example, we discuss how changes to the abundance, function and activation status of specific immune cell populations can affect the transmission of prion diseases by peripheral routes. We also describe how the effects of systemic inflammation on certain glial cell subsets in the brains of infected individuals can accelerate the neurodegeneration. A detailed understanding of the factors that affect prion disease transmission and pathogenesis is essential for the development of novel intervention strategies.
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Affiliation(s)
- Neil A. Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK; (B.M.B.); (R.P.); (R.Y.); (D.S.D.)
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Effect of co-infection with a small intestine-restricted helminth pathogen on oral prion disease pathogenesis in mice. Sci Rep 2019; 9:6674. [PMID: 31040320 PMCID: PMC6491469 DOI: 10.1038/s41598-019-42900-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/11/2019] [Indexed: 11/24/2022] Open
Abstract
The early replication of some orally-acquired prion strains upon stromal-derived follicular dendritic cells (FDC) within the small intestinal Peyer’s patches is essential to establish host infection, and for the disease to efficiently spread to the brain. Factors that influence the early accumulation of prions in Peyer’s patches can directly influence disease pathogenesis. The host’s immune response to a gastrointestinal helminth infection can alter susceptibility to co-infection with certain pathogenic bacteria and viruses. Here we used the natural mouse small intestine-restricted helminth pathogen Heligmosomoides polygyrus to test the hypothesis that pathology specifically within the small intestine caused by a helminth co-infection would influence oral prion disease pathogenesis. When mice were co-infected with prions on d 8 after H. polygyrus infection the early accumulation of prions within Peyer’s patches was reduced and survival times significantly extended. Natural prion susceptible hosts such as sheep, deer and cattle are regularly exposed to gastrointestinal helminth parasites. Our data suggest that co-infections with small intestine-restricted helminth pathogens may be important factors that influence oral prion disease pathogenesis.
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Kara E, Marks JD, Aguzzi A. Toxic Protein Spread in Neurodegeneration: Reality versus Fantasy. Trends Mol Med 2018; 24:1007-1020. [DOI: 10.1016/j.molmed.2018.09.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/14/2018] [Accepted: 09/20/2018] [Indexed: 12/22/2022]
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Keller A, Nuvolone M, Abakumova I, Chincisan A, Reimann R, Avar M, Heinzer D, Hornemann S, Wagner J, Kirschenbaum D, Voigt FF, Zhu C, Regli L, Helmchen F, Aguzzi A. Prion pathogenesis is unaltered in a mouse strain with a permeable blood-brain barrier. PLoS Pathog 2018; 14:e1007424. [PMID: 30496289 PMCID: PMC6264140 DOI: 10.1371/journal.ppat.1007424] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 10/19/2018] [Indexed: 01/01/2023] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) are caused by the prion, which consists essentially of PrPSc, an aggregated, conformationally modified form of the cellular prion protein (PrPC). Although TSEs can be experimentally transmitted by intracerebral inoculation, most instances of infection in the field occur through extracerebral routes. The epidemics of kuru and variant Creutzfeldt-Jakob disease were caused by dietary exposure to prions, and parenteral administration of prion-contaminated hormones has caused hundreds of iatrogenic TSEs. In all these instances, the development of postexposure prophylaxis relies on understanding of how prions propagate from the site of entry to the brain. While much evidence points to lymphoreticular invasion followed by retrograde transfer through peripheral nerves, prions are present in the blood and may conceivably cross the blood-brain barrier directly. Here we have addressed the role of the blood-brain barrier (BBB) in prion disease propagation using Pdgfbret/ret mice which possess a highly permeable BBB. We found that Pdgfbret/ret mice have a similar prion disease incubation time as their littermate controls regardless of the route of prion transmission. These surprising results indicate that BBB permeability is irrelevant to the initiation of prion disease, even when prions are administered parenterally.
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Affiliation(s)
- Annika Keller
- Department of Neurosurgery, Clinical Neuroscience Centre, University Hospital Zürich, Zürich University, Zürich, Switzerland
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Mario Nuvolone
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
- Amyloidosis Research and Treatment Center, Foundation IRCCS Policlinico San Matteo, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Irina Abakumova
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Andra Chincisan
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Regina Reimann
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Merve Avar
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Daniel Heinzer
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Simone Hornemann
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Josephin Wagner
- Department of Neurosurgery, Clinical Neuroscience Centre, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Daniel Kirschenbaum
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Fabian F. Voigt
- Brain Research Institute, Zürich University, Zürich, Switzerland
- Neuroscience Center Zürich (ZNZ), University of Zürich and ETH Zürich, Zürich, Switzerland
| | - Caihong Zhu
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Luca Regli
- Department of Neurosurgery, Clinical Neuroscience Centre, University Hospital Zürich, Zürich University, Zürich, Switzerland
| | - Fritjof Helmchen
- Brain Research Institute, Zürich University, Zürich, Switzerland
- Neuroscience Center Zürich (ZNZ), University of Zürich and ETH Zürich, Zürich, Switzerland
| | - Adriano Aguzzi
- Institute of Neuropathology, University Hospital Zürich, Zürich University, Zürich, Switzerland
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Oral Prion Neuroinvasion Occurs Independently of PrP C Expression in the Gut Epithelium. J Virol 2018; 92:JVI.01010-18. [PMID: 30021891 PMCID: PMC6146811 DOI: 10.1128/jvi.01010-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 07/11/2018] [Indexed: 01/22/2023] Open
Abstract
The accumulation of orally acquired prions within Peyer's patches in the small intestine is essential for the efficient spread of disease to the brain. Little is known of how the prions initially establish infection within Peyer's patches. Some gastrointestinal pathogens utilize molecules, such as the cellular prion protein PrPC, expressed on gut epithelial cells to enter Peyer's patches. Acute mucosal inflammation can enhance PrPC expression in the intestine, implying the potential to enhance oral prion disease susceptibility. We used transgenic mice to determine whether the uptake of prions into Peyer's patches was dependent upon PrPC expression in the gut epithelium. We show that orally acquired prions can establish infection in Peyer's patches independently of PrPC expression in gut epithelial cells. Our data suggest that the magnitude of PrPC expression in the epithelium lining the small intestine is unlikely to be an important factor which influences oral prion disease susceptibility. The early replication of certain prion strains within Peyer's patches in the small intestine is essential for the efficient spread of disease to the brain after oral exposure. Our data show that orally acquired prions utilize specialized gut epithelial cells known as M cells to enter Peyer's patches. M cells express the cellular isoform of the prion protein, PrPC, and this may be exploited by some pathogens as an uptake receptor to enter Peyer's patches. This suggested that PrPC might also mediate the uptake and transfer of prions across the gut epithelium into Peyer's patches in order to establish infection. Furthermore, the expression level of PrPC in the gut epithelium could influence the uptake of prions from the lumen of the small intestine. To test this hypothesis, transgenic mice were created in which deficiency in PrPC was specifically restricted to epithelial cells throughout the lining of the small intestine. Our data clearly show that efficient prion neuroinvasion after oral exposure occurred independently of PrPC expression in small intestinal epithelial cells. The specific absence of PrPC in the gut epithelium did not influence the early replication of prions in Peyer's patches or disease susceptibility. Acute mucosal inflammation can enhance PrPC expression in the intestine, implying the potential to enhance oral prion disease pathogenesis and susceptibility. However, our data suggest that the magnitude of PrPC expression in the epithelium lining the small intestine is unlikely to be an important factor which influences the risk of oral prion disease susceptibility. IMPORTANCE The accumulation of orally acquired prions within Peyer's patches in the small intestine is essential for the efficient spread of disease to the brain. Little is known of how the prions initially establish infection within Peyer's patches. Some gastrointestinal pathogens utilize molecules, such as the cellular prion protein PrPC, expressed on gut epithelial cells to enter Peyer's patches. Acute mucosal inflammation can enhance PrPC expression in the intestine, implying the potential to enhance oral prion disease susceptibility. We used transgenic mice to determine whether the uptake of prions into Peyer's patches was dependent upon PrPC expression in the gut epithelium. We show that orally acquired prions can establish infection in Peyer's patches independently of PrPC expression in gut epithelial cells. Our data suggest that the magnitude of PrPC expression in the epithelium lining the small intestine is unlikely to be an important factor which influences oral prion disease susceptibility.
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Mabbott NA. How do PrP Sc Prions Spread between Host Species, and within Hosts? Pathogens 2017; 6:pathogens6040060. [PMID: 29186791 PMCID: PMC5750584 DOI: 10.3390/pathogens6040060] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 11/16/2017] [Accepted: 11/21/2017] [Indexed: 12/22/2022] Open
Abstract
Prion diseases are sub-acute neurodegenerative diseases that affect humans and some domestic and free-ranging animals. Infectious prion agents are considered to comprise solely of abnormally folded isoforms of the cellular prion protein known as PrPSc. Pathology during prion disease is restricted to the central nervous system where it causes extensive neurodegeneration and ultimately leads to the death of the host. The first half of this review provides a thorough account of our understanding of the various ways in which PrPSc prions may spread between individuals within a population, both horizontally and vertically. Many natural prion diseases are acquired peripherally, such as by oral exposure, lesions to skin or mucous membranes, and possibly also via the nasal cavity. Following peripheral exposure, some prions accumulate to high levels within the secondary lymphoid organs as they make their journey from the site of infection to the brain, a process termed neuroinvasion. The replication of PrPSc prions within secondary lymphoid organs is important for their efficient spread to the brain. The second half of this review describes the key tissues, cells and molecules which are involved in the propagation of PrPSc prions from peripheral sites of exposure (such as the lumen of the intestine) to the brain. This section also considers how additional factors such as inflammation and aging might influence prion disease susceptibility.
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Affiliation(s)
- Neil A Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
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Relative Impact of Complement Receptors CD21/35 (Cr2/1) on Scrapie Pathogenesis in Mice. mSphere 2017; 2:mSphere00493-17. [PMID: 29202042 PMCID: PMC5700378 DOI: 10.1128/mspheredirect.00493-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 10/30/2017] [Indexed: 01/18/2023] Open
Abstract
Mammalian prion diseases are caused by prions, unique infectious agents composed primarily, if not solely, of a pathologic, misfolded form of a normal host protein, the cellular prion protein (PrPC). Prions replicate without a genetic blueprint, but rather contact PrPC and coerce it to misfold into more prions, which cause neurodegeneration akin to other protein-misfolding diseases like Alzheimer’s disease. A single gene produces two alternatively spliced mRNA transcripts that encode mouse complement receptors CD21/35, which promote efficient prion replication in the lymphoid system and eventual movement to the brain. Here we show that CD21/35 are high-affinity prion receptors, but mice expressing only CD21 die from prion disease sooner than CD35-expressing mice, which contain less prions early after infection and exhibit delayed terminal disease, likely due to their less organized splenic follicles. Thus, CD21 appears to be more important for defining splenic architecture that influences prion pathogenesis. Complement receptors 1 and 2 (CR1/2 or CD35/CD21) recognize complement-opsonized antigens to initiate innate and adaptive immunity, respectively. CD35 stimulates phagocytosis on macrophages and antigen presentation on follicular dendritic cells (FDCs). CD21 helps activate B cells as part of the B cell coreceptor with CD19 and CD81. Differential splicing of transcripts from the mouse Cr2 gene generates isoforms with both shared and unique complement binding capacities and cell-type expression. In mouse models, genetic depletion of Cr2 causes either a delay or complete prevention of prion disease, but the relative importance of CD35 versus CD21 in promoting prion disease remains unknown. Here we show that both isoforms act as high-affinity cell surface prion receptors. However, mice lacking CD21 succumbed to terminal prion disease significantly later than mice lacking CD35 or wild-type and hemizygous mice. CD21-deficient mice contained fewer splenic prions than CD35 knockout mice early after infection that contributed to delayed prion neuroinvasion and terminal disease, despite forming follicular networks closer to proximal nerves. While we observed no difference in B cell networks, PrPC expression, or number of follicles, CD21-deficient mice formed more fragmented, less organized follicular networks with fewer Mfge8-positive FDCs and/or tingible body macrophages (TBMφs) than wild-type or CD35-deficient mice. In toto, these data demonstrate a more prominent role for CD21 for proper follicular development and organization leading to more efficient lymphoid prion replication and expedited prion disease than in mice expressing the CD35 isoform. IMPORTANCE Mammalian prion diseases are caused by prions, unique infectious agents composed primarily, if not solely, of a pathologic, misfolded form of a normal host protein, the cellular prion protein (PrPC). Prions replicate without a genetic blueprint, but rather contact PrPC and coerce it to misfold into more prions, which cause neurodegeneration akin to other protein-misfolding diseases like Alzheimer’s disease. A single gene produces two alternatively spliced mRNA transcripts that encode mouse complement receptors CD21/35, which promote efficient prion replication in the lymphoid system and eventual movement to the brain. Here we show that CD21/35 are high-affinity prion receptors, but mice expressing only CD21 die from prion disease sooner than CD35-expressing mice, which contain less prions early after infection and exhibit delayed terminal disease, likely due to their less organized splenic follicles. Thus, CD21 appears to be more important for defining splenic architecture that influences prion pathogenesis.
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Kane SJ, Farley TK, Gordon EO, Estep J, Bender HR, Moreno JA, Bartz J, Telling GC, Pickering MC, Zabel MD. Complement Regulatory Protein Factor H Is a Soluble Prion Receptor That Potentiates Peripheral Prion Pathogenesis. THE JOURNAL OF IMMUNOLOGY 2017; 199:3821-3827. [PMID: 29070671 DOI: 10.4049/jimmunol.1701100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/29/2017] [Indexed: 01/16/2023]
Abstract
Several complement proteins exacerbate prion disease, including C3, C1q, and CD21/35. These proteins of the complement cascade likely increase uptake, trafficking, and retention of prions in the lymphoreticular system, hallmark sites of early prion propagation. Complement regulatory protein factor H (fH) binds modified host proteins and lipids to prevent C3b deposition and, thus, autoimmune cell lysis. Previous reports show that fH binds various conformations of the cellular prion protein, leading us to question the role of fH in prion disease. In this article, we report that transgenic mice lacking Cfh alleles exhibit delayed peripheral prion accumulation, replication, and pathogenesis and onset of terminal disease in a gene-dose manner. We also report a biophysical interaction between purified fH and prion rods enriched from prion-diseased brain. fH also influences prion deposition in brains of infected mice. We conclude from these data and previous findings that the interplay between complement and prions likely involves a complex balance of prion sequestration and destruction via local tissue macrophages, prion trafficking by B and dendritic cells within the lymphoreticular system, intranodal prion replication by B and follicular dendritic cells, and potential prion strain selection by CD21/35 and fH. These findings reveal a novel role for complement-regulatory proteins in prion disease.
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Affiliation(s)
- Sarah J Kane
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Taylor K Farley
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.,National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Elizabeth O Gordon
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Joshua Estep
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Heather R Bender
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Julie A Moreno
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Jason Bartz
- School of Medicine, Creighton University, Omaha, NE 68178; and
| | - Glenn C Telling
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Matthew C Pickering
- Department of Medicine, Centre for Complement and Inflammation Research, Imperial College, London W12 0NN, United Kingdom
| | - Mark D Zabel
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523;
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Mabbott NA. Immunology of Prion Protein and Prions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:203-240. [PMID: 28838662 DOI: 10.1016/bs.pmbts.2017.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Many natural prion diseases are acquired peripherally, such as following the oral consumption of contaminated food or pasture. After peripheral exposure many prion isolates initially accumulate to high levels within the host's secondary lymphoid tissues. The replication of prions within these tissues is essential for their efficient spread to the brain where they ultimately cause neurodegeneration. This chapter describes our current understanding of the critical tissues, cells, and molecules which the prions exploit to mediate their efficient propagation from the site of exposure (such as the intestine) to the brain. Interactions between the immune system and prions are not only restricted to the secondary lymphoid tissues. Therefore, an account of how the activation status of the microglial in the brain can also influence progression of prion disease pathogenesis is provided. Prion disease susceptibility may also be influenced by additional factors such as chronic inflammation, coinfection with other pathogens, and aging. Finally, the potential for immunotherapy to provide a means of safe and effective prophylactic or therapeutic intervention in these currently untreatable diseases is considered.
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Affiliation(s)
- Neil A Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Midlothian, United Kingdom.
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Oral Prion Disease Pathogenesis Is Impeded in the Specific Absence of CXCR5-Expressing Dendritic Cells. J Virol 2017; 91:JVI.00124-17. [PMID: 28275192 PMCID: PMC5411578 DOI: 10.1128/jvi.00124-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 03/02/2017] [Indexed: 01/09/2023] Open
Abstract
After oral exposure, the early replication of certain prion strains upon stromal cell-derived follicular dendritic cells (FDC) in the Peyer's patches in the small intestine is essential for the efficient spread of disease to the brain. However, little is known of how prions are initially conveyed from the gut lumen to establish infection on FDC. Our previous data suggest that mononuclear phagocytes such as CD11c+ conventional dendritic cells play an important role in the initial propagation of prions from the gut lumen into Peyer's patches. However, whether these cells conveyed orally acquired prions toward FDC within Peyer's patches was not known. The chemokine CXCL13 is expressed by FDC and follicular stromal cells and modulates the homing of CXCR5-expressing cells toward the FDC-containing B cell follicles. Here, novel compound transgenic mice were created in which a CXCR5 deficiency was specifically restricted to CD11c+ cells. These mice were used to determine whether CXCR5-expressing conventional dendritic cells propagate prions toward FDC after oral exposure. Our data show that in the specific absence of CXCR5-expressing conventional dendritic cells the early accumulation of prions upon FDC in Peyer's patches and the spleen was impaired, and disease susceptibility significantly reduced. These data suggest that CXCR5-expressing conventional dendritic cells play an important role in the efficient propagation of orally administered prions toward FDC within Peyer's patches in order to establish host infection.IMPORTANCE Many natural prion diseases are acquired by oral consumption of contaminated food or pasture. Once the prions reach the brain they cause extensive neurodegeneration, which ultimately leads to death. In order for the prions to efficiently spread from the gut to the brain, they first replicate upon follicular dendritic cells within intestinal Peyer's patches. How the prions are first delivered to follicular dendritic cells to establish infection was unknown. Understanding this process is important since treatments which prevent prions from infecting follicular dendritic cells can block their spread to the brain. We created mice in which mobile conventional dendritic cells were unable to migrate toward follicular dendritic cells. In these mice the early accumulation of prions on follicular dendritic cells was impaired and oral prion disease susceptibility was reduced. This suggests that prions exploit conventional dendritic cells to facilitate their initial delivery toward follicular dendritic cells to establish host infection.
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Brandner S, Jaunmuktane Z. Prion disease: experimental models and reality. Acta Neuropathol 2017; 133:197-222. [PMID: 28084518 PMCID: PMC5250673 DOI: 10.1007/s00401-017-1670-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/04/2017] [Accepted: 01/05/2017] [Indexed: 01/04/2023]
Abstract
The understanding of the pathogenesis and mechanisms of diseases requires a multidisciplinary approach, involving clinical observation, correlation to pathological processes, and modelling of disease mechanisms. It is an inherent challenge, and arguably impossible to generate model systems that can faithfully recapitulate all aspects of human disease. It is, therefore, important to be aware of the potentials and also the limitations of specific model systems. Model systems are usually designed to recapitulate only specific aspects of the disease, such as a pathological phenotype, a pathomechanism, or to test a hypothesis. Here, we evaluate and discuss model systems that were generated to understand clinical, pathological, genetic, biochemical, and epidemiological aspects of prion diseases. Whilst clinical research and studies on human tissue are an essential component of prion research, much of the understanding of the mechanisms governing transmission, replication, and toxicity comes from in vitro and in vivo studies. As with other neurodegenerative diseases caused by protein misfolding, the pathogenesis of prion disease is complex, full of conundra and contradictions. We will give here a historical overview of the use of models of prion disease, how they have evolved alongside the scientific questions, and how advancements in technologies have pushed the boundaries of our understanding of prion biology.
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Affiliation(s)
- Sebastian Brandner
- Department of Neurodegenerative Disease, UCL Institute of Neurology and Division of Neuropathology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, Queen Square, London, WC1N 3BG UK
| | - Zane Jaunmuktane
- Department of Neurodegenerative Disease, UCL Institute of Neurology and Division of Neuropathology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, Queen Square, London, WC1N 3BG UK
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Donaldson DS, Sehgal A, Rios D, Williams IR, Mabbott NA. Increased Abundance of M Cells in the Gut Epithelium Dramatically Enhances Oral Prion Disease Susceptibility. PLoS Pathog 2016; 12:e1006075. [PMID: 27973593 PMCID: PMC5156364 DOI: 10.1371/journal.ppat.1006075] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/17/2016] [Indexed: 02/07/2023] Open
Abstract
Many natural prion diseases of humans and animals are considered to be acquired through oral consumption of contaminated food or pasture. Determining the route by which prions establish host infection will identify the important factors that influence oral prion disease susceptibility and to which intervention strategies can be developed. After exposure, the early accumulation and replication of prions within small intestinal Peyer's patches is essential for the efficient spread of disease to the brain. To replicate within Peyer's patches, the prions must first cross the gut epithelium. M cells are specialised epithelial cells within the epithelia covering Peyer's patches that transcytose particulate antigens and microorganisms. M cell-development is dependent upon RANKL-RANK-signalling, and mice in which RANK is deleted only in the gut epithelium completely lack M cells. In the specific absence of M cells in these mice, the accumulation of prions within Peyer's patches and the spread of disease to the brain was blocked, demonstrating a critical role for M cells in the initial transfer of prions across the gut epithelium in order to establish host infection. Since pathogens, inflammatory stimuli and aging can modify M cell-density in the gut, these factors may also influence oral prion disease susceptibility. Mice were therefore treated with RANKL to enhance M cell density in the gut. We show that prion uptake from the gut lumen was enhanced in RANKL-treated mice, resulting in shortened survival times and increased disease susceptibility, equivalent to a 10-fold higher infectious titre of prions. Together these data demonstrate that M cells are the critical gatekeepers of oral prion infection, whose density in the gut epithelium directly limits or enhances disease susceptibility. Our data suggest that factors which alter M cell-density in the gut epithelium may be important risk factors which influence host susceptibility to orally acquired prion diseases.
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Affiliation(s)
- David S. Donaldson
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, United Kingdom
| | - Anuj Sehgal
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, United Kingdom
| | - Daniel Rios
- Dept. Pathology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Ifor R. Williams
- Dept. Pathology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Neil A. Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, United Kingdom
- * E-mail:
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Paltrinieri S, Comazzi S, Spagnolo V, Rondena M, Ponti W, Ceciliani F. Bovine Doppel (Dpl) and Prion Protein (PrP) Expression on Lymphoid Tissue and Circulating Leukocytes. J Histochem Cytochem 2016; 52:1639-45. [PMID: 15557218 DOI: 10.1369/jhc.4a6441.2004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Doppel (Dpl) protein shares some structural features with prion protein (PrP), whose pathologic isoform (PrPsc) is considered to be the causative agent of transmissible spongiform encephalopathies. Dpl is mainly expressed in testes but, when ectopically expressed in the central nervous system, is neurotoxic. We have examined the expression pattern of Dpl and PrP on bovine lymphoid tissues and circulating leukocytes. A polyclonal anti-Dpl antibody along with a panel of monoclonal antibodies specific for leukocyte membrane antigens or PrP were used to examine frozen sections from spleen, lymph nodes, and bone marrow by immunohistochemistry. Blood was analyzed by flow cytometry. Double staining was used to study the possible coexpression of the two proteins and to characterize cells expressing Dpl and/or PrP. Dpl was expressed in B-cells, in dendritic cells within lymphoid follicles, bone marrow, circulating myeloid cells, and circulating B-cells. The distribution of Dpl was quite similar to that of PrP. The only differences in expression observed concerned the low number of Dpl + cells in lymph nodes and the strong Dpl positivity of circulating granulocytes. The two proteins were rarely co-expressed, suggesting an independent expression mechanism in resting cells. The role of Dpl+ leukocytes in the pathogenesis of Dpl- or PrP-induced diseases merits further investigation.
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Affiliation(s)
- Saverio Paltrinieri
- Department of Veterinary Pathology, Hygiene and Health, University of Milan, Milan, Italy.
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15
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The Good, the Bad, and the Ugly of Dendritic Cells during Prion Disease. J Immunol Res 2015; 2015:168574. [PMID: 26697507 PMCID: PMC4677227 DOI: 10.1155/2015/168574] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 11/15/2015] [Indexed: 12/11/2022] Open
Abstract
Prions are a unique group of proteinaceous pathogens which cause neurodegenerative disease and can be transmitted by a variety of exposure routes. After peripheral exposure, the accumulation and replication of prions within secondary lymphoid organs are obligatory for their efficient spread from the periphery to the brain where they ultimately cause neurodegeneration and death. Mononuclear phagocytes (MNP) are a heterogeneous population of dendritic cells (DC) and macrophages. These cells are abundant throughout the body and display a diverse range of roles based on their anatomical locations. For example, some MNP are strategically situated to provide a first line of defence against pathogens by phagocytosing and destroying them. Conventional DC are potent antigen presenting cells and migrate via the lymphatics to the draining lymphoid tissue where they present the antigens to lymphocytes. The diverse roles of MNP are also reflected in various ways in which they interact with prions and in doing so impact on disease pathogenesis. Indeed, some studies suggest that prions exploit conventional DC to infect the host. Here we review our current understanding of the influence of MNP in the pathogenesis of the acquired prion diseases with particular emphasis on the role of conventional DC.
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16
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Abstract
Individuals infected with prions succumb to brain damage, and prion infections continue to be inexorably lethal. However, many crucial steps in prion pathogenesis occur in lymphatic organs and precede invasion of the central nervous system. In the past two decades, a great deal has been learnt concerning the cellular and molecular mechanisms of prion lymphoinvasion. These properties are diagnostically useful and have, for example, facilitated preclinical diagnosis of variant Creutzfeldt-Jakob disease in the tonsils. Moreover, the early colonization of lymphoid organs can be exploited for post-exposure prophylaxis of prion infections. As stromal cells of lymphoid organs are crucial for peripheral prion infection, the dedifferentiation of these cells offers a powerful means of hindering prion spread in infected individuals. In this Review, we discuss the current knowledge of the immunobiology of prions with an emphasis on how basic discoveries might enable translational strategies.
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Klöhn PC, Castro-Seoane R, Collinge J. Exosome release from infected dendritic cells: a clue for a fast spread of prions in the periphery? J Infect 2013; 67:359-68. [PMID: 23911964 DOI: 10.1016/j.jinf.2013.07.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/11/2013] [Accepted: 07/23/2013] [Indexed: 11/18/2022]
Abstract
Prion diseases are incurable transmissible neurological disorders. In many natural and experimental prion diseases, infectious prions can be detected in the lymphoreticular system (LRS) long before they reach the brain where they cause a fatal rapidly progressive degeneration. Although major cell types that contribute to prion accumulation have been identified, the mode of prion dissemination in the LRS remains elusive. Recent evidence of a remarkably fast splenic prion accumulation after peripheral infection of mice, resulting in high prion titers in dendritic cells (DCs) and a release of prions from infected DCs via exosomes suggest that intercellular dissemination may contribute to rapid prion colonization in the LRS. A vast body of evidence from retroviral infections shows that DCs and other antigen-presenting cells (APCs) share viral antigens by intercellular transfer to warrant immunity against viruses if APCs remain uninfected. Evolved to adapt the immune response to evading pathogens, these pathways may constitute a portal for unimpeded prion dissemination owing to the tolerance of the immune system against host-encoded prion protein. In this review we summarize current paradigms for antigen-sharing pathways which may be relevant to better understand dissemination of rogue neurotoxic proteins.
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Affiliation(s)
- Peter-Christian Klöhn
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
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18
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Abstract
Prion colonization of secondary lymphoid organs (SLOs) is a critical step preceding neuroinvasion in prion pathogenesis. Follicular dendritic cells (FDCs), which depend on both tumor necrosis factor receptor 1 (TNFR1) and lymphotoxin β receptor (LTβR) signaling for maintenance, are thought to be the primary sites of prion accumulation in SLOs. However, prion titers in RML-infected TNFR1 (-/-) lymph nodes and rates of neuroinvasion in TNFR1 (-/-) mice remain high despite the absence of mature FDCs. Recently, we discovered that TNFR1-independent prion accumulation in lymph nodes relies on LTβR signaling. Loss of LTβR signaling in TNFR1 (-/-) lymph nodes coincided with the de-differentiation of high endothelial venules (HEVs)-the primary sites of lymphocyte entry into lymph nodes. These findings suggest that HEVs are the sites through which prions initially invade lymph nodes from the bloodstream. Identification of HEVs as entry portals for prions clarifies a number of previous observations concerning peripheral prion pathogenesis. However, a number of questions still remain: What is the mechanism by which prions are taken up by HEVs? Which cells are responsible for delivering prions to lymph nodes? Are HEVs the main entry site for prions into lymph nodes or do alternative routes also exist? These questions and others are considered in this article.
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Affiliation(s)
- Tracy O'Connor
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland.
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Roettger Y, Du Y, Bacher M, Zerr I, Dodel R, Bach JP. Immunotherapy in prion disease. Nat Rev Neurol 2012; 9:98-105. [DOI: 10.1038/nrneurol.2012.258] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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20
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Michel B, Ferguson A, Johnson T, Bender H, Meyerett-Reid C, Pulford B, von Teichman A, Seelig D, Weis JH, Telling GC, Aguzzi A, Zabel MD. Genetic depletion of complement receptors CD21/35 prevents terminal prion disease in a mouse model of chronic wasting disease. THE JOURNAL OF IMMUNOLOGY 2012; 189:4520-7. [PMID: 23002439 DOI: 10.4049/jimmunol.1201579] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The complement system has been shown to facilitate peripheral prion pathogenesis. Mice lacking complement receptors CD21/35 partially resist terminal prion disease when infected i.p. with mouse-adapted scrapie prions. Chronic wasting disease (CWD) is an emerging prion disease of captive and free-ranging cervid populations that, similar to scrapie, has been shown to involve the immune system, which probably contributes to their relatively facile horizontal and environmental transmission. In this study, we show that mice overexpressing the cervid prion protein and susceptible to CWD (Tg(cerPrP)5037 mice) but lack CD21/35 expression completely resist clinical CWD upon peripheral infection. CD21/35-deficient Tg5037 mice exhibit greatly impaired splenic prion accumulation and replication throughout disease, similar to CD21/35-deficient murine prion protein mice infected with mouse scrapie. TgA5037;CD21/35(-/-) mice exhibited little or no neuropathology and deposition of misfolded, protease-resistant prion protein associated with CWD. CD21/35 translocate to lipid rafts and mediates a strong germinal center response to prion infection that we propose provides the optimal environment for prion accumulation and replication. We further propose a potential role for CD21/35 in selecting prion quasi-species present in prion strains that may exhibit differential zoonotic potential compared with the parental strains.
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Affiliation(s)
- Brady Michel
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University Prion Research Center, Fort Collins, CO 80523, USA
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21
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Mabbott NA. Prion pathogenesis and secondary lymphoid organs (SLO): tracking the SLO spread of prions to the brain. Prion 2012; 6:322-33. [PMID: 22895090 PMCID: PMC3609058 DOI: 10.4161/pri.20676] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Prion diseases are subacute neurodegenerative diseases that affect humans and a range of domestic and free-ranging animal species. These diseases are characterized by the accumulation of PrPSc, an abnormally folded isoform of the cellular prion protein (PrPC), in affected tissues. The pathology during prion disease appears to occur almost exclusively within the central nervous system. The extensive neurodegeneration which occurs ultimately leads to the death of the host. An intriguing feature of the prion diseases, when compared with other protein-misfolding diseases, is their transmissibility. Following peripheral exposure, some prion diseases accumulate to high levels within lymphoid tissues. The replication of prions within lymphoid tissue has been shown to be important for the efficient spread of disease to the brain. This article describes recent progress in our understanding of the cellular mechanisms that influence the propagation of prions from peripheral sites of exposure (such as the lumen of the intestine) to the brain. A thorough understanding of these events will lead to the identification of important targets for therapeutic intervention, or alternatively, reveal additional processes that influence disease susceptibility to peripherally-acquired prion diseases.
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Affiliation(s)
- Neil A Mabbott
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, Midlothian, UK.
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22
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O'Connor T, Frei N, Sponarova J, Schwarz P, Heikenwalder M, Aguzzi A. Lymphotoxin, but not TNF, is required for prion invasion of lymph nodes. PLoS Pathog 2012; 8:e1002867. [PMID: 22912582 PMCID: PMC3415451 DOI: 10.1371/journal.ppat.1002867] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 07/05/2012] [Indexed: 12/19/2022] Open
Abstract
Neuroinvasion and subsequent destruction of the central nervous system by prions are typically preceded by a colonization phase in lymphoid organs. An important compartment harboring prions in lymphoid tissue is the follicular dendritic cell (FDC), which requires both tumor necrosis factor receptor 1 (TNFR1) and lymphotoxin β receptor (LTβR) signaling for maintenance. However, prions are still detected in TNFR1−/− lymph nodes despite the absence of mature FDCs. Here we show that TNFR1-independent prion accumulation in lymph nodes depends on LTβR signaling. Loss of LTβR signaling, but not of TNFR1, was concurrent with the dedifferentiation of high endothelial venules (HEVs) required for lymphocyte entry into lymph nodes. Using luminescent conjugated polymers for histochemical PrPSc detection, we identified PrPSc deposits associated with HEVs in TNFR1−/− lymph nodes. Hence, prions may enter lymph nodes by HEVs and accumulate or replicate in the absence of mature FDCs. Prions are unique infectious agents thought to be composed entirely of an abnormal conformer of the endogenous prion protein. Prions cause a severe neurological disorder in humans and other animals known as prion disease. Though prion disease can arise spontaneously or from genetic mutations in the gene encoding the prion protein, many cases of prion disease arise due to peripheral exposure to the infectious agent. In these cases, prions must journey from the gastrointestinal tract and/or the bloodstream to the brain. Prions often colonize secondary lymphoid organs prior to invading the nervous system via neighboring peripheral nerves. Prion accumulation in follicular dendritic cells found in germinal centers of lymphoid organs is thought to be a crucial step in this process. However, prion colonization of lymph nodes, in contrast to spleen, does not depend on follicular dendritic cells, indicating that other mechanisms must exist. Here, we identify the signaling pathway required for follicular dendritic cell-independent prion colonization of lymph nodes, which also controls the differentiation of high endothelial venules, the primary entry point for lymphocytes into lymph nodes. Importantly, prions could be found within these structures, indicating that high endothelial venules are required for prion entry and accumulation in lymph nodes.
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MESH Headings
- Animals
- Dendritic Cells, Follicular/immunology
- Dendritic Cells, Follicular/metabolism
- Dendritic Cells, Follicular/pathology
- Lymph Nodes/immunology
- Lymph Nodes/metabolism
- Lymph Nodes/pathology
- Lymphotoxin beta Receptor/genetics
- Lymphotoxin beta Receptor/immunology
- Lymphotoxin beta Receptor/metabolism
- Lymphotoxin-alpha/genetics
- Lymphotoxin-alpha/immunology
- Lymphotoxin-alpha/metabolism
- Mice
- Mice, Knockout
- PrPSc Proteins/genetics
- PrPSc Proteins/immunology
- PrPSc Proteins/metabolism
- Receptors, Tumor Necrosis Factor, Type I/genetics
- Receptors, Tumor Necrosis Factor, Type I/immunology
- Receptors, Tumor Necrosis Factor, Type I/metabolism
- Scrapie/genetics
- Scrapie/immunology
- Scrapie/metabolism
- Scrapie/pathology
- Signal Transduction/genetics
- Signal Transduction/immunology
- Tumor Necrosis Factor-alpha/genetics
- Tumor Necrosis Factor-alpha/immunology
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Tracy O'Connor
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland
- * E-mail: TracyLynn.O' (TO); (AA)
| | - Nathalie Frei
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland
| | - Jana Sponarova
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland
| | - Petra Schwarz
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland
| | | | - Adriano Aguzzi
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland
- * E-mail: TracyLynn.O' (TO); (AA)
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Mok SWF, Proia RL, Brinkmann V, Mabbott NA. B cell-specific S1PR1 deficiency blocks prion dissemination between secondary lymphoid organs. THE JOURNAL OF IMMUNOLOGY 2012; 188:5032-40. [PMID: 22504650 DOI: 10.4049/jimmunol.1200349] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Many prion diseases are peripherally acquired (e.g., orally or via lesions to skin or mucous membranes). After peripheral exposure, prions replicate first upon follicular dendritic cells (FDC) in the draining lymphoid tissue before infecting the brain. However, after replication upon FDC within the draining lymphoid tissue, prions are subsequently propagated to most nondraining secondary lymphoid organs (SLO), including the spleen, by a previously underdetermined mechanism. The germinal centers in which FDC are situated produce a population of B cells that can recirculate between SLO. Therefore, we reasoned that B cells were ideal candidates by which prion dissemination between SLO may occur. Sphingosine 1-phosphate receptor (S1PR)1 stimulation controls the egress of T and B cells from SLO. S1PR1 signaling blockade sequesters lymphocytes within SLO, resulting in lymphopenia in the blood and lymph. We show that, in mice treated with the S1PR modulator FTY720 or with S1PR1 deficiency restricted to B cells, the dissemination of prions from the draining lymph node to nondraining SLO is blocked. These data suggest that B cells interacting with and acquiring surface proteins from FDC and recirculating between SLO via the blood and lymph mediate the initial propagation of prions from the draining lymphoid tissue to peripheral tissues.
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Affiliation(s)
- Simon W F Mok
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Midlothian EH25 9RG, United Kingdom
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24
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Abstract
Many prion diseases are orally acquired. Our data show that after oral exposure, early prion replication upon follicular dendritic cells (FDC) in Peyer's patches is obligatory for the efficient spread of disease to the brain (termed neuroinvasion). For prions to replicate on FDC within Peyer's patches after ingestion of a contaminated meal, they must first cross the gut epithelium. However, the mechanism through which prions are conveyed into Peyer's patches is uncertain. Within the follicle-associated epithelium overlying Peyer's patches are microfold cells (M cells), unique epithelial cells specialized for the transcytosis of particles. We show that following M cell-depletion, early prion accumulation upon FDC in Peyer's patches is blocked. Furthermore, in the absence of M cells at the time of oral exposure, neuroinvasion and disease development are likewise blocked. These data suggest M cells are important sites of prion uptake from the gut lumen into Peyer's patches.
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25
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Wathne GJ, Kissenpfennig A, Malissen B, Zurzolo C, Mabbott NA. Determining the role of mononuclear phagocytes in prion neuroinvasion from the skin. J Leukoc Biol 2012; 91:817-28. [PMID: 22389312 DOI: 10.1189/jlb.1211633] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Many prion diseases are acquired by peripheral exposure, and skin lesions are an effective route of transmission. Following exposure, early prion replication, upon FDCs in the draining LN is obligatory for the spread of disease to the brain. However, the mechanism by which prions are conveyed to the draining LN is uncertain. Here, transgenic mice were used, in which langerin(+) cells, including epidermal LCs and langerin(+) classical DCs, were specifically depleted. These were used in parallel with transgenic mice, in which nonepidermal CD11c(+) cells were specifically depleted. Our data show that prion pathogenesis, following exposure via skin scarification, occurred independently of LC and other langerin(+) cells. However, the depletion of nonepidermal CD11c(+) cells impaired the early accumulation of prions in the draining LN, implying a role for these cells in the propagation of prions from the skin. Therefore, together, these data suggest that the propagation of prions from the skin to the draining LN occurs via dermal classical DCs, independently of langerin(+) cells.
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26
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Biochemical properties of highly neuroinvasive prion strains. PLoS Pathog 2012; 8:e1002522. [PMID: 22319450 PMCID: PMC3271082 DOI: 10.1371/journal.ppat.1002522] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 12/21/2011] [Indexed: 11/24/2022] Open
Abstract
Infectious prions propagate from peripheral entry sites into the central nervous system (CNS), where they cause progressive neurodegeneration that ultimately leads to death. Yet the pathogenesis of prion disease can vary dramatically depending on the strain, or conformational variant of the aberrantly folded and aggregated protein, PrPSc. Although most prion strains invade the CNS, some prion strains cannot gain entry and do not cause clinical signs of disease. The conformational basis for this remarkable variation in the pathogenesis among strains is unclear. Using mouse-adapted prion strains, here we show that highly neuroinvasive prion strains primarily form diffuse aggregates in brain and are noncongophilic, conformationally unstable in denaturing conditions, and lead to rapidly lethal disease. These neuroinvasive strains efficiently generate PrPSc over short incubation periods. In contrast, the weakly neuroinvasive prion strains form large fibrillary plaques and are stable, congophilic, and inefficiently generate PrPSc over long incubation periods. Overall, these results indicate that the most neuroinvasive prion strains are also the least stable, and support the concept that the efficient replication and unstable nature of the most rapidly converting prions may be a feature linked to their efficient spread into the CNS. Prion diseases are fatal neurodegenerative disorders that are also infectious. Prions are composed of a misfolded, aggregated form of a normal cellular protein that is highly expressed in neurons. Prion- infected individuals show variability in the clinical signs and brain regions that selectively accumulate prions, even within the same species expressing the same prion protein sequence. The basis of these divergent disease phenotypes is unclear, but is thought to be due to different conformations of the misfolded prion protein, known as strains. Here we characterized the neuropathology and biochemical properties of prion strains that efficiently or poorly invade the CNS from their peripheral entry site. We show that prion strains that efficiently invade the CNS also cause a rapidly terminal disease after an intracerebral exposure. These rapidly lethal strains were unstable when exposed to denaturants or high temperatures, and efficiently accumulated misfolded prion protein over a short incubation period in vivo. Our findings indicate that the most invasive, rapidly spreading strains are also the least conformationally stable.
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27
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Castro-Seoane R, Hummerich H, Sweeting T, Tattum MH, Linehan JM, Fernandez de Marco M, Brandner S, Collinge J, Klöhn PC. Plasmacytoid dendritic cells sequester high prion titres at early stages of prion infection. PLoS Pathog 2012; 8:e1002538. [PMID: 22359509 PMCID: PMC3280992 DOI: 10.1371/journal.ppat.1002538] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 01/04/2012] [Indexed: 12/22/2022] Open
Abstract
In most transmissible spongiform encephalopathies prions accumulate in the lymphoreticular system (LRS) long before they are detectable in the central nervous system. While a considerable body of evidence showed that B lymphocytes and follicular dendritic cells play a major role in prion colonization of lymphoid organs, the contribution of various other cell types, including antigen-presenting cells, to the accumulation and the spread of prions in the LRS are not well understood. A comprehensive study to compare prion titers of candidate cell types has not been performed to date, mainly due to limitations in the scope of animal bioassays where prohibitively large numbers of mice would be required to obtain sufficiently accurate data. By taking advantage of quantitative in vitro prion determination and magnetic-activated cell sorting, we studied the kinetics of prion accumulation in various splenic cell types at early stages of prion infection. Robust estimates for infectious titers were obtained by statistical modelling using a generalized linear model. Whilst prions were detectable in B and T lymphocytes and in antigen-presenting cells like dendritic cells and macrophages, highest infectious titers were determined in two cell types that have previously not been associated with prion pathogenesis, plasmacytoid dendritic (pDC) and natural killer (NK) cells. At 30 days after infection, NK cells were more than twice, and pDCs about seven-fold, as infectious as lymphocytes respectively. This result was unexpected since, in accordance to previous reports prion protein, an obligate requirement for prion replication, was undetectable in pDCs. This underscores the importance of prion sequestration and dissemination by antigen-presenting cells which are among the first cells of the immune system to encounter pathogens. We furthermore report the first evidence for a release of prions from lymphocytes and DCs of scrapie-infected mice ex vivo, a process that is associated with a release of exosome-like membrane vesicles.
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Affiliation(s)
- Rocio Castro-Seoane
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
| | - Holger Hummerich
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
| | - Trevor Sweeting
- Department of Statistical Science, University College London, London, United Kingdom
| | - M. Howard Tattum
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
| | - Jacqueline M. Linehan
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
| | - Mar Fernandez de Marco
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
| | - Sebastian Brandner
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
| | - John Collinge
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
| | - Peter-Christian Klöhn
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
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28
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Co-infection with the friend retrovirus and mouse scrapie does not alter prion disease pathogenesis in susceptible mice. PLoS One 2012; 7:e30872. [PMID: 22295118 PMCID: PMC3266293 DOI: 10.1371/journal.pone.0030872] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Accepted: 12/22/2011] [Indexed: 11/19/2022] Open
Abstract
Prion diseases are fatal, transmissible neurodegenerative diseases of the central nervous system. An abnormally protease-resistant and insoluble form (PrP(Sc)) of the normally soluble protease-sensitive host prion protein (PrP(C)) is the major component of the infectious prion. During the course of prion disease, PrP(Sc) accumulates primarily in the lymphoreticular and central nervous systems. Recent studies have shown that co-infection of prion-infected fibroblast cells with the Moloney murine leukemia virus (Mo-MuLV) strongly enhanced the release and spread of scrapie infectivity in cell culture, suggesting that retroviral coinfection might significantly influence prion spread and disease incubation times in vivo. We now show that another retrovirus, the murine leukemia virus Friend (F-MuLV), also enhanced the release and spread of scrapie infectivity in cell culture. However, peripheral co-infection of mice with both Friend virus and the mouse scrapie strain 22L did not alter scrapie disease incubation times, the levels of PrP(Sc) in the brain or spleen, or the distribution of pathological lesions in the brain. Thus, retroviral co-infection does not necessarily alter prion disease pathogenesis in vivo, most likely because of different cell-specific sites of replication for scrapie and F-MuLV.
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29
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Kujala P, Raymond CR, Romeijn M, Godsave SF, van Kasteren SI, Wille H, Prusiner SB, Mabbott NA, Peters PJ. Prion uptake in the gut: identification of the first uptake and replication sites. PLoS Pathog 2011; 7:e1002449. [PMID: 22216002 PMCID: PMC3245311 DOI: 10.1371/journal.ppat.1002449] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 11/04/2011] [Indexed: 01/10/2023] Open
Abstract
After oral exposure, prions are thought to enter Peyer's patches via M cells and accumulate first upon follicular dendritic cells (FDCs) before spreading to the nervous system. How prions are actually initially acquired from the gut lumen is not known. Using high-resolution immunofluorescence and cryo-immunogold electron microscopy, we report the trafficking of the prion protein (PrP) toward Peyer's patches of wild-type and PrP-deficient mice. PrP was transiently detectable at 1 day post feeding (dpf) within large multivesicular LAMP1-positive endosomes of enterocytes in the follicle-associated epithelium (FAE) and at much lower levels within M cells. Subsequently, PrP was detected on vesicles in the late endosomal compartments of macrophages in the subepithelial dome. At 7-21 dpf, increased PrP labelling was observed on the plasma membranes of FDCs in germinal centres of Peyer's patches from wild-type mice only, identifying FDCs as the first sites of PrP conversion and replication. Detection of PrP on extracellular vesicles displaying FAE enterocyte-derived A33 protein implied transport towards FDCs in association with FAE-derived vesicles. By 21 dpf, PrP was observed on the plasma membranes of neurons within neighbouring myenteric plexi. Together, these data identify a novel potential M cell-independent mechanism for prion transport, mediated by FAE enterocytes, which acts to initiate conversion and replication upon FDCs and subsequent infection of enteric nerves.
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Affiliation(s)
- Pekka Kujala
- Section of Cell Biology II, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Claudine R. Raymond
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
| | - Martijn Romeijn
- Section of Cell Biology II, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Susan F. Godsave
- Section of Cell Biology II, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | - Holger Wille
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, California, United States of America
| | - Stanley B. Prusiner
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, California, United States of America
| | - Neil A. Mabbott
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
| | - Peter J. Peters
- Section of Cell Biology II, Netherlands Cancer Institute, Amsterdam, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
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McCulloch L, Brown KL, Bradford BM, Hopkins J, Bailey M, Rajewsky K, Manson JC, Mabbott NA. Follicular dendritic cell-specific prion protein (PrP) expression alone is sufficient to sustain prion infection in the spleen. PLoS Pathog 2011; 7:e1002402. [PMID: 22144895 PMCID: PMC3228802 DOI: 10.1371/journal.ppat.1002402] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 10/11/2011] [Indexed: 11/20/2022] Open
Abstract
Prion diseases are characterised by the accumulation of PrPSc, an abnormally folded isoform of the cellular prion protein (PrPC), in affected tissues. Following peripheral exposure high levels of prion-specific PrPSc accumulate first upon follicular dendritic cells (FDC) in lymphoid tissues before spreading to the CNS. Expression of PrPC is mandatory for cells to sustain prion infection and FDC appear to express high levels. However, whether FDC actively replicate prions or simply acquire them from other infected cells is uncertain. In the attempts to-date to establish the role of FDC in prion pathogenesis it was not possible to dissociate the Prnp expression of FDC from that of the nervous system and all other non-haematopoietic lineages. This is important as FDC may simply acquire prions after synthesis by other infected cells. To establish the role of FDC in prion pathogenesis transgenic mice were created in which PrPC expression was specifically “switched on” or “off” only on FDC. We show that PrPC-expression only on FDC is sufficient to sustain prion replication in the spleen. Furthermore, prion replication is blocked in the spleen when PrPC-expression is specifically ablated only on FDC. These data definitively demonstrate that FDC are the essential sites of prion replication in lymphoid tissues. The demonstration that Prnp-ablation only on FDC blocked splenic prion accumulation without apparent consequences for FDC status represents a novel opportunity to prevent neuroinvasion by modulation of PrPC expression on FDC. Prion diseases are infectious neurological disorders and are considered to be caused by an abnormally folded infectious protein termed PrPSc. Soon after infection prions accumulate first upon follicular dendritic cells (FDC) in lymphoid tissues before spreading to the brain where they cause damage to nerve cells. Cells must express the normal cellular prion protein PrPC to become infected with prions. However, whether FDC are infected with prions or simply acquire them from other infected cells is unknown. To establish the role of FDC in prion disease PrPC expression was specifically “switched on” or “off” only on FDC. We show that PrPC-expressing FDC alone are sufficient to sustain prion replication in the spleen. Furthermore, prion replication is blocked in the spleen when PrPC-expression is switched off only on FDC. These data definitively demonstrate that FDC are the essential sites of prion replication in lymphoid tissues.
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Affiliation(s)
- Laura McCulloch
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Midlothian, United Kingdom
| | - Karen L. Brown
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Midlothian, United Kingdom
| | - Barry M. Bradford
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Midlothian, United Kingdom
| | - John Hopkins
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Midlothian, United Kingdom
| | - Mick Bailey
- Division of Veterinary Pathology, Infection and Immunity, School of Clinical Veterinary Science, University of Bristol, Avon, United Kingdom
| | - Klaus Rajewsky
- Program in Cellular and Molecular Medicine, Children's Hospital, and Immune Disease Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jean C. Manson
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Midlothian, United Kingdom
| | - Neil A. Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Midlothian, United Kingdom
- * E-mail:
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Erhabor O, Adias TC. From whole blood to component therapy: the economic, supply/demand need for implementation of component therapy in sub-Saharan Africa. Transfus Clin Biol 2011; 18:516-26. [PMID: 22037104 DOI: 10.1016/j.tracli.2011.06.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 06/26/2011] [Indexed: 11/28/2022]
Abstract
Blood may be transfused as whole blood or as one of its components. Because patients seldom require all of the components of whole blood, it makes sense to transfuse only that portion needed by the patient for a specific condition or disease. This treatment, known as "blood component therapy", allows several patients to benefit from one unit of donated whole blood. Blood components include red blood cells, plasma, platelets, and cryoprecipitate. A considerable literature has accumulated over the past decade indicating that leukocytes present in allogeneic cellular blood components, intended for transfusion, are associated with adverse effects to the recipient. These include the development of febrile transfusion reactions, graft-versus-host disease, alloimmunization to leukocyte antigens, and the immunomodulatory effects that might influence the prognosis of patients with a malignancy. Moreover, it has become evident that such leukocytes may be the vector of infectious agents such as cytomegalovirus (CMV), Human T-Lymphotrophic Virus 1/11 (HTLV-I/II), and Epstein Barr (EBV) as well as other viruses. Effective stewardship of blood ensuring that several patients potentially benefit from components derived from one unit of donated whole blood is important for economic, supply/demand reasons and to protect the national inventory at times of national blood shortage. Blood safety in developing countries can be improved by more appropriate use of blood components rather than whole blood transfusion and the provision of alternatives such as oral and intravenous iron, erythropoietin, saline and colloids. This will facilitate the optimal use of the limited blood supply. Political will and open-mindedness to innovative ways to improve supply, appropriateness, optimal use and safety of blood from all types of donors are essential to promote more evidence-based approaches to blood transfusion practice in sub-Saharan Africa.
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Affiliation(s)
- O Erhabor
- Department of Blood Sciences, Royal Bolton Hospital NHS Trust UK, 4, Minerva Road, BL4 0JR Bolton, United Kingdom.
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The effects of host age on the transport of complement-bound complexes to the spleen and the pathogenesis of intravenous scrapie infection. J Virol 2011; 86:25-35. [PMID: 22031932 DOI: 10.1128/jvi.05581-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infections with variant Creutzfeldt-Jakob disease (vCJD) have almost exclusively occurred in young patients, but the reasons for this age distribution are uncertain. Our data suggest that the pathogenesis of many peripherally acquired transmissible spongiform encephalopathy (TSE) agents is less efficient in aged individuals. Four vCJD cases linked to transfusion of vCJD-contaminated blood or blood products have been described. Three cases occurred in elderly patients, implying that intravenous exposure is more efficient in aged individuals than other peripheral routes. To test this hypothesis, young (6 to 8 weeks old) and aged (600 days old) mice were injected intravenously with a TSE agent. In aged and young mice, the intravenous route was more efficient than other peripheral routes of TSE agent exposure. However, in aged mice, disease pathogenesis was significantly reduced. Although most aged mice failed to develop clinical disease during their life spans, many showed histopathological signs of TSE disease in their brains. Thus, the effects of age on intravenous TSE pathogenesis may lead to significant levels of subclinical disease in the population. After peripheral exposure, many TSE agents accumulate upon follicular dendritic cells (FDCs) in lymphoid tissues before they infect the brain. In aged spleens, PrP(C) expression and TSE agent accumulation upon FDCs were reduced. Furthermore, the splenic marginal zone microarchitecture was substantially disturbed, adversely affecting the delivery of immune complexes to FDCs. This study is the first to suggest that the effects of aging on the microarchitecture and the function of the splenic marginal zone significantly influence the pathogenesis of an important pathogen.
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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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Haybaeck J, Heikenwalder M, Klevenz B, Schwarz P, Margalith I, Bridel C, Mertz K, Zirdum E, Petsch B, Fuchs TJ, Stitz L, Aguzzi A. Aerosols transmit prions to immunocompetent and immunodeficient mice. PLoS Pathog 2011; 7:e1001257. [PMID: 21249178 PMCID: PMC3020930 DOI: 10.1371/journal.ppat.1001257] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 12/13/2010] [Indexed: 12/03/2022] Open
Abstract
Prions, the agents causing transmissible spongiform encephalopathies, colonize the brain of hosts after oral, parenteral, intralingual, or even transdermal uptake. However, prions are not generally considered to be airborne. Here we report that inbred and crossbred wild-type mice, as well as tga20 transgenic mice overexpressing PrP(C), efficiently develop scrapie upon exposure to aerosolized prions. NSE-PrP transgenic mice, which express PrP(C) selectively in neurons, were also susceptible to airborne prions. Aerogenic infection occurred also in mice lacking B- and T-lymphocytes, NK-cells, follicular dendritic cells or complement components. Brains of diseased mice contained PrP(Sc) and transmitted scrapie when inoculated into further mice. We conclude that aerogenic exposure to prions is very efficacious and can lead to direct invasion of neural pathways without an obligatory replicative phase in lymphoid organs. This previously unappreciated risk for airborne prion transmission may warrant re-thinking on prion biosafety guidelines in research and diagnostic laboratories.
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Affiliation(s)
- Johannes Haybaeck
- Department of Pathology, Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
| | - Mathias Heikenwalder
- Department of Pathology, Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
| | - Britta Klevenz
- Institute of Immunology, Friedrich-Loeffler-Institut, Tübingen, Germany
| | - Petra Schwarz
- Department of Pathology, Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
| | - Ilan Margalith
- Department of Pathology, Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
| | - Claire Bridel
- Department of Pathology, Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
| | - Kirsten Mertz
- Department of Pathology, Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
- Department of Pathology, Clinical Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Elizabeta Zirdum
- Institute of Immunology, Friedrich-Loeffler-Institut, Tübingen, Germany
| | - Benjamin Petsch
- Institute of Immunology, Friedrich-Loeffler-Institut, Tübingen, Germany
| | - Thomas J. Fuchs
- Department of Computer Science, Machine Learning Laboratory, ETH Zurich, Zurich, Switzerland
| | - Lothar Stitz
- Institute of Immunology, Friedrich-Loeffler-Institut, Tübingen, Germany
| | - Adriano Aguzzi
- Department of Pathology, Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
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Prion replication in the hematopoietic compartment is not required for neuroinvasion in scrapie mouse model. PLoS One 2010; 5. [PMID: 20957200 PMCID: PMC2950141 DOI: 10.1371/journal.pone.0013166] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 09/11/2010] [Indexed: 01/31/2023] Open
Abstract
Fatal neurodegenerative prion diseases are caused by the transmissible PrPSc prion agent whose initial replication after peripheral inoculation takes place in follicular dendritic cells present in germinal centers of lymphoid organs. However, prion replication also occurs in lymphoid cells. To assess the role of the hematopoietic compartment in neuroinvasion and prion replication, we generated chimeric mice, on a uniform congenic C57/BL6J background, by bone marrow replacement with hematopoietic cells expressing different levels of PrP protein. Nine different types of chimeric mice were inoculated intraperitoneally either with the lymphotropic Rocky Mountain Laboratory (RML) strain or the non lymphotropic ME-7 scrapie strain, at different doses. Here, we clearly demonstrate that overexpression of PrP by the hematopoietic system, or the lack of PrP expression by the bone marrow derived cells, does not change the incubation time period of the disease, even when the mice are infected at limiting doses. We conclude that the hematopoietic compartment is more or less permissive to prion replication, both for RML and ME-7, but does not play a role in neuroinvasion.
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36
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Edwards JC, Moore SJ, Hawthorn JA, Neale MH, Terry LA. PrPSc is associated with B cells in the blood of scrapie-infected sheep. Virology 2010; 405:110-9. [DOI: 10.1016/j.virol.2010.05.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 05/03/2010] [Accepted: 05/21/2010] [Indexed: 11/25/2022]
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Bachy V, Aucouturier P. [Prion diseases: what is the role of dendritic cells in the pathogenesis of transmissible prion diseases?]. Med Sci (Paris) 2010; 26:615-20. [PMID: 20619164 DOI: 10.1051/medsci/2010266-7615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Prion diseases are caused by the transconformation of a normal cellular protein, PrPc, into an infectious isoform, PrPsc, which ultimately triggers neuronal death. They are always fatal and, after transmission, they feature long incubation periods, during which prions accumulate in lymphoid tissues, infect nerves and progress to the central nervous system. In lymphoid organs, prions replicate and accumulate in follicular dendritic cells. Suppressing these cells slows down the neuro-invasion but does not totally abrogate it. This review examines the current knowledge in the roles of hematopoietic dendritic cells at different steps of the pathogenesis of prion diseases. Dendritic cells endocytose inoculated prions, permit their crossing of the intestinal epithelium and then migrate and transport them to lymphoid organs. They can carry prions to sites of neuroinvasion, and establish contacts with axons in peripheral lymph nodes or even after passage of the blood-brain barrier. However, results in the literature on the role of dendritic cells differ according to the host or the prion strain.
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38
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Sisó S, González L, Jeffrey M. Neuroinvasion in prion diseases: the roles of ascending neural infection and blood dissemination. Interdiscip Perspect Infect Dis 2010; 2010:747892. [PMID: 20652006 PMCID: PMC2905956 DOI: 10.1155/2010/747892] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 03/08/2010] [Indexed: 01/27/2023] Open
Abstract
Prion disorders are infectious, neurodegenerative diseases that affect humans and animals. Susceptibility to some prion diseases such as kuru or the new variant of Creutzfeldt-Jakob disease in humans and scrapie in sheep and goats is influenced by polymorphisms of the coding region of the prion protein gene, while other prion disorders such as fatal familial insomnia, familial Creutzfeldt-Jakob disease, or Gerstmann-Straussler-Scheinker disease in humans have an underlying inherited genetic basis. Several prion strains have been demonstrated experimentally in rodents and sheep. The progression and pathogenesis of disease is influenced by both genetic differences in the prion protein and prion strain. Some prion diseases only affect the central nervous system whereas others involve the peripheral organs prior to neuroinvasion. Many experiments undertaken in different species and using different prion strains have postulated common pathways of neuroinvasion. It is suggested that prions access the autonomic nerves innervating peripheral organs and tissues to finally reach the central nervous system. We review here published data supporting this view and additional data suggesting that neuroinvasion may concurrently or independently involve the blood vascular system.
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Affiliation(s)
- Sílvia Sisó
- Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK
| | - Lorenzo González
- Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK
| | - Martin Jeffrey
- Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK
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Bassuni WY, Blajchman MA, Al-Moshary MA. Why implement universal leukoreduction? Hematol Oncol Stem Cell Ther 2010; 1:106-23. [PMID: 20063539 DOI: 10.1016/s1658-3876(08)50042-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The improvement of transfusion medicine technology is an ongoing process primarily directed at increasing the safety of allogeneic blood component transfusions for recipients. Over the years, relatively little attention had been paid to the leukocytes present in the various blood components. The availability of leukocyte removal (leukoreduction) techniques for blood components is associated with a considerable improvement in various clinical outcomes. These include a reduction in the frequency and severity of febrile transfusion reactions, reduced cytomegalovirus transfusion-transmission risk, the reduced incidence of alloimmune platelet refractoriness, a possible reduction in the risk of transfusion-associated variant Creutzfeldt-Jakob disease transmission, as well as reducing the overall risk of both recipient mortality and organ dysfunction, particularly in cardiac surgery patients and possibly in other categories of patients. Internationally, 19 countries have implemented universal leukocyte reduction (ULR) as part of their blood safety policy. The main reason for not implementing ULR in those countries that have not appears to be primarily concerns over costs. Nonetheless, the available international experience supports the concept that ULR is a process that results in improved safety of allogeneic blood components.
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Affiliation(s)
- Wafaa Y Bassuni
- Central Laboratory and Transfusion Services, King Fahad Medical City, Riyadh, Saudi Arabia.
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40
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Makarava N, Kovacs GG, Bocharova O, Savtchenko R, Alexeeva I, Budka H, Rohwer RG, Baskakov IV. Recombinant prion protein induces a new transmissible prion disease in wild-type animals. Acta Neuropathol 2010; 119:177-87. [PMID: 20052481 PMCID: PMC2808531 DOI: 10.1007/s00401-009-0633-x] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 12/22/2009] [Accepted: 12/22/2009] [Indexed: 12/16/2022]
Abstract
Prion disease is a neurodegenerative malady, which is believed to be transmitted via a prion protein in its abnormal conformation (PrP(Sc)). Previous studies have failed to demonstrate that prion disease could be induced in wild-type animals using recombinant prion protein (rPrP) produced in Escherichia coli. Here, we report that prion infectivity was generated in Syrian hamsters after inoculating full-length rPrP that had been converted into the cross-beta-sheet amyloid form and subjected to annealing. Serial transmission gave rise to a disease phenotype with highly unique clinical and neuropathological features. Among them were the deposition of large PrP(Sc) plaques in subpial and subependymal areas in brain and spinal cord, very minor lesioning of the hippocampus and cerebellum, and a very slow progression of disease after onset of clinical signs despite the accumulation of large amounts of PrP(Sc) in the brain. The length of the clinical duration is more typical of human and large animal prion diseases, than those of rodents. Our studies establish that transmissible prion disease can be induced in wild-type animals by inoculation of rPrP and introduce a valuable new model of prion diseases.
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Affiliation(s)
- Natallia Makarava
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 W. Lombard St., Baltimore, MD 21201 USA
| | - Gabor G. Kovacs
- Institute of Neurology, Medical University of Vienna, AKH 4J, 1097 Vienna, Austria
| | - Olga Bocharova
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 W. Lombard St., Baltimore, MD 21201 USA
| | - Regina Savtchenko
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 W. Lombard St., Baltimore, MD 21201 USA
| | - Irina Alexeeva
- Medical Research Service, Veterans Affairs Maryland Health Care System, 10 North Greene Street, Baltimore, MD 21201 USA
| | - Herbert Budka
- Institute of Neurology, Medical University of Vienna, AKH 4J, 1097 Vienna, Austria
| | - Robert G. Rohwer
- Medical Research Service, Veterans Affairs Maryland Health Care System, 10 North Greene Street, Baltimore, MD 21201 USA
- Department of Neurology, University of Maryland, Baltimore, MD 21201 USA
| | - Ilia V. Baskakov
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 W. Lombard St., Baltimore, MD 21201 USA
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD 21201 USA
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Abstract
Transmissible spongiform encephalopathies (TSEs) are inevitably lethal neurodegenerative diseases that affect humans and a large variety of animals. The infectious agent responsible for TSEs is the prion, an abnormally folded and aggregated protein that propagates itself by imposing its conformation onto the cellular prion protein (PrPC) of the host. PrPCis necessary for prion replication and for prion-induced neurodegeneration, yet the proximal causes of neuronal injury and death are still poorly understood. Prion toxicity may arise from the interference with the normal function of PrPC, and therefore, understanding the physiological role of PrPCmay help to clarify the mechanism underlying prion diseases. Here we discuss the evolution of the prion concept and how prion-like mechanisms may apply to other protein aggregation diseases. We describe the clinical and the pathological features of the prion diseases in human and animals, the events occurring during neuroinvasion, and the possible scenarios underlying brain damage. Finally, we discuss potential antiprion therapies and current developments in the realm of prion diagnostics.
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Brown KL, Wathne GJ, Sales J, Bruce ME, Mabbott NA. The effects of host age on follicular dendritic cell status dramatically impair scrapie agent neuroinvasion in aged mice. THE JOURNAL OF IMMUNOLOGY 2009; 183:5199-207. [PMID: 19786551 DOI: 10.4049/jimmunol.0802695] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Following peripheral exposure, many transmissible spongiform encephalopathy (TSE) agents accumulate first in lymphoid tissues before spreading to the CNS (termed neuroinvasion) where they cause neurodegeneration. Early TSE agent accumulation upon follicular dendritic cells (FDCs) in lymphoid follicles appears critical for efficient neuroinvasion. Most clinical cases of variant Creutzfeldt-Jakob disease have occurred in young adults, although the reasons behind this apparent age-related susceptibility are uncertain. Host age has a significant influence on immune function. As FDC status and immune complex trapping is reduced in aged mice (600 days old), we hypothesized that this aging-related decline in FDC function might impair TSE pathogenesis. We show that coincident with the effects of host age on FDC status, the early TSE agent accumulation in the spleens of aged mice was significantly impaired. Furthermore, following peripheral exposure, none of the aged mice developed clinical TSE disease during their lifespans, although most mice displayed histopathological signs of TSE disease in their brains. Our data imply that the reduced status of FDCs in aged mice significantly impairs the early TSE agent accumulation in lymphoid tissues and subsequent neuroinvasion. Furthermore, the inefficient neuroinvasion in aged individuals may lead to significant levels of subclinical TSE disease in the population.
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Affiliation(s)
- Karen L Brown
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Roslin, United Kingdom
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43
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Peralta OA, Eyestone WH. Quantitative and qualitative analysis of cellular prion protein (PrP(C)) expression in bovine somatic tissues. Prion 2009; 3:161-70. [PMID: 19806026 DOI: 10.4161/pri.3.3.9772] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The host encoded cellular prion protein (PrP(C)) is an N-linked glycoprotein tethered to the cell membrane by a glycophosphatidylinositol (GPI) anchor. Under certain conditions, PrP(C) can undergo conversion into a conformationally-altered isoform (PrP(Sc)) widely believed to be the pathogenic agent of transmissible spongiform encephalopathies (TSEs). Understanding the tissue-specific expression of PrP(C) is crucial considering that cells expressing high levels of PrP(C) bear a risk for conversion and accumulation of PrP(Sc). In the present study, fifteen bovine somatic tissues were analyzed for PrP(C) expression by quantitative western blot and immunohistochemistry. Quantitative western blot analysis revealed highest expression of PrP(C) in cerebellum, obex and spinal cord. Intermediate levels were detected in thymus, intestine, nerve, heart and spleen, and lower levels in lung, muscle, kidney, lymph node, skin, pancreas and liver. Immunohistochemical analysis detected intense cellular-specific PrP(C) staining in neurons, thymocytes and lymphocytes. PrP(C) was also detected in the enteric wall, pancreatic islets of langerhans, myocardium, pulmonary alveolar sacs, renal glomeruli and dermal epithelial cells. This study demonstrated the quantitatively varied, wide-spread, tissue- and cell-specific expression pattern of PrP(C) in bovine somatic tissues. The importance of this study is to lay the foundation for understanding the tissue-specific expression of PrP(C) and to consider the potential participation of more bovine tissues in the transmission of BSE infection.
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Affiliation(s)
- Oscar A Peralta
- Department of Large Animal Clinical Sciences, Virginia Polytechnic Institute and State University, Blacksburg, USA
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44
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Nuvolone M, Aguzzi A, Heikenwalder M. Cells and prions: A license to replicate. FEBS Lett 2009; 583:2674-84. [DOI: 10.1016/j.febslet.2009.06.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/01/2009] [Accepted: 06/09/2009] [Indexed: 10/20/2022]
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Segarra C, Lehmann S, Coste J. Prion protein expression and processing in human mononuclear cells: the impact of the codon 129 prion gene polymorphism. PLoS One 2009; 4:e5796. [PMID: 19495414 PMCID: PMC2686158 DOI: 10.1371/journal.pone.0005796] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 04/22/2009] [Indexed: 01/19/2023] Open
Abstract
Background So far, all clinical cases of new variant Creutzfeldt-Jakob disease (vCJD), thought to result from the Bovine Spongiform Encephalopathy (BSE) prion agent, have shown Methionine–Methionine (M/M) homozygosity at the M129V polymorphism of the PRNP gene. Although established, this relationship is still not understood. In both vCJD and experimental BSE models prion agents do reach the bloodstream, raising concerns regarding disease transmission through blood transfusion. Methodology/Principal Findings We investigated the impact of the M129V polymorphism on the expression and processing of the prion protein in human peripheral blood mononuclear cells (PBMCs) from three blood donor populations with Methionine-Methionine (M/M), Valine-Valine (V/V) and M/V genotypes. Using real-time PCR, ELISA and immunoblot assays we were unable to find differences in prion protein expression and processing relating to the M129V polymorphism. Conclusions/Significance These results suggest that in PBMCs, the M129V PrP polymorphism has no significant impact on PrP expression, processing and the apparent glycoform distribution. Prion propagation should be investigated further in other cell types or tissues.
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Affiliation(s)
- Christiane Segarra
- Etablissement Français du Sang de Pyrénées Méditerranée, Montpellier, France
| | - Sylvain Lehmann
- Institut de Génétique Humaine, UPR1142 CNRS, /CHU Montpellier/UM1 Montpellier, Montpellier, France
| | - Joliette Coste
- Etablissement Français du Sang de Pyrénées Méditerranée, Montpellier, France
- * E-mail:
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Coste J, Prowse C, Eglin R, Fang C. A report on transmissible spongiform encephalopathies and transfusion safety. Vox Sang 2009; 96:284-91. [DOI: 10.1111/j.1423-0410.2009.01161.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhou H, Zhou X, Kouadir M, Zhang Z, Yin X, Yang L, Zhao D. Induction of macrophage migration by neurotoxic prion protein fragment. J Neurosci Methods 2009; 181:1-5. [PMID: 19447501 DOI: 10.1016/j.jneumeth.2009.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 04/02/2009] [Accepted: 04/03/2009] [Indexed: 01/07/2023]
Abstract
Prion diseases are characterized by accumulation of protease resistant isoforms of prion protein (PrP), and infiltration and activation of mononuclear phagocytes at the brain lesions. Interactions between prion proteins and immune cells during disease progression are still not very well understood. In the present study, multiwell chamber chemotaxis assay was carried out to assess the migratory response of macrophage cell line Ana-1 to a synthetic peptide homologous to residues 106-126 of the human prion protein. Specific protein kinase inhibitors were used to elucidate the signaling events underlying PrP106-126-induced macrophages migration, and a comparison with the signaling pattern of macrophage migration induced by substance P (SP) and N-formyl-methionyl-leucyl-phenylalanine (fMLP), respectively, was carried out. The results showed that PrP106-126 had a potent chemotactic effect on murine macrophage cell line Ana-1; that multiple signaling pathways might be involved in the PrP106-126-induced macrophage migrations; and that PrP106-126-induced chemotactic activity was similar to that induced by SP. These findings provide new insights into the mechanisms underlying the interaction between PrP and macrophages.
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Affiliation(s)
- Haiyun Zhou
- National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, People's Republic of China
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Heikenwalder M, Kurrer MO, Margalith I, Kranich J, Zeller N, Haybaeck J, Polymenidou M, Matter M, Bremer J, Jackson WS, Lindquist S, Sigurdson CJ, Aguzzi A. Lymphotoxin-Dependent Prion Replication in Inflammatory Stromal Cells of Granulomas. Immunity 2008; 29:998-1008. [DOI: 10.1016/j.immuni.2008.10.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 09/10/2008] [Accepted: 10/13/2008] [Indexed: 11/28/2022]
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Aguzzi A, Sigurdson C, Heikenwaelder M. Molecular mechanisms of prion pathogenesis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 3:11-40. [PMID: 18233951 DOI: 10.1146/annurev.pathmechdis.3.121806.154326] [Citation(s) in RCA: 253] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Prion diseases are infectious neurodegenerative diseases occurring in humans and animals with an invariably lethal outcome. One fundamental mechanistic event in prion diseases is the aggregation of aberrantly folded prion protein into large amyloid plaques and fibrous structures associated with neurodegeneration. The cellular prion protein (PrPC) is absolutely required for disease development, and prion knockout mice are not susceptible to prion disease. Prions accumulate not only in the central nervous system but also in lymphoid organs, as shown for new variant and sporadic Creutzfeldt-Jakob patients and for some animals. To date it is largely accepted that prions consist primarily of PrPSc, a misfolded and aggregated beta-sheet-rich isoform of PrPC. However, PrPSc may or may not be completely congruent with the infectious moiety. Here, we discuss the molecular mechanisms leading to neurodegeneration, the role of the immune system in prion pathogenesis, and the existence of prion strains that appear to have different tropisms and biochemical characteristics.
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Affiliation(s)
- Adriano Aguzzi
- Institute of Neuropathology, University Hospital of Zürich, CH-8091 Zürich, Switzerland.
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LeBrun M, Huang H, Li X. Susceptibility of cell substrates to PrPSc infection and safety control measures related to biological and biotherapeutical products. Prion 2008; 2:17-22. [PMID: 19164901 DOI: 10.4161/pri.2.1.6280] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Concerns over the potential for infectious prion proteins to contaminate human biologics and biotherapeutics have been raised from time to time. Transmission of the pathogenic form of prion protein (PrP(Sc)) through veterinary vaccines has been observed, yet no human case through the use of vaccine products has been reported. However, iatrogenic transmissions of PrP(Sc) in humans through blood components, tissues and growth hormone have been reported. These findings underscore the importance of reliable detection or diagnostic methods to prevent the transmission of prion diseases, given that the number of asymptomatic infected individuals remains unknown, the perceived incubation time for human prion diseases could be decades, and no cure of the diseases has been found yet. A variety of biochemical and molecular methods can selectively concentrate PrP(Sc) to facilitate its detection in tissues and cells. Furthermore, some methods routinely used in the manufacturing process of biological products have been found to be effective in reducing PrP(Sc) from the products. Questions remain unanswered as to the validation criteria of these methods, the minimal infectious dose of the PrP(Sc) required to cause infection and the susceptibility of cells used in gene therapy or the manufacturing process of biological products to PrP(Sc) infections. Here, we discuss some of these challenging issues.
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Affiliation(s)
- Matthew LeBrun
- Centre for Biologics Research, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
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