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Baiardi S, Mammana A, Capellari S, Parchi P. Human prion disease: molecular pathogenesis, and possible therapeutic targets and strategies. Expert Opin Ther Targets 2023; 27:1271-1284. [PMID: 37334903 DOI: 10.1080/14728222.2023.2199923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/03/2023] [Indexed: 06/21/2023]
Abstract
INTRODUCTION Human prion diseases are heterogeneous, and often rapidly progressive, transmissible neurodegenerative disorders associated with misfolded prion protein (PrP) aggregation and self-propagation. Despite their rarity, prion diseases comprise a broad spectrum of phenotypic variants determined at the molecular level by different conformers of misfolded PrP and host genotype variability. Moreover, they uniquely occur in idiopathic, genetically determined, and acquired forms with distinct etiologies. AREA COVERED This review provides an up-to-date overview of potential therapeutic targets in prion diseases and the main results obtained in cell and animal models and human trials. The open issues and challenges associated with developing effective therapies and informative clinical trials are also discussed. EXPERT OPINION Currently tested therapeutic strategies target the cellular PrP to prevent the formation of misfolded PrP or to favor its elimination. Among them, passive immunization and gene therapy with antisense oligonucleotides against prion protein mRNA are the most promising. However, the disease's rarity, heterogeneity, and rapid progression profoundly frustrate the successful undertaking of well-powered therapeutic trials and patient identification in the asymptomatic or early stage before the development of significant brain damage. Thus, the most promising therapeutic goal to date is preventing or delaying phenoconversion in carriers of pathogenic mutations by lowering prion protein expression.
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Affiliation(s)
- Simone Baiardi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Angela Mammana
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Sabina Capellari
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Piero Parchi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
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Avar M, Heinzer D, Thackray AM, Liu Y, Hruska‐Plochan M, Sellitto S, Schaper E, Pease DP, Yin J, Lakkaraju AKK, Emmenegger M, Losa M, Chincisan A, Hornemann S, Polymenidou M, Bujdoso R, Aguzzi A. An arrayed genome-wide perturbation screen identifies the ribonucleoprotein Hnrnpk as rate-limiting for prion propagation. EMBO J 2022; 41:e112338. [PMID: 36254605 PMCID: PMC9713719 DOI: 10.15252/embj.2022112338] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/17/2022] [Accepted: 09/22/2022] [Indexed: 01/15/2023] Open
Abstract
A defining characteristic of mammalian prions is their capacity for self-sustained propagation. Theoretical considerations and experimental evidence suggest that prion propagation is modulated by cell-autonomous and non-autonomous modifiers. Using a novel quantitative phospholipase protection assay (QUIPPER) for high-throughput prion measurements, we performed an arrayed genome-wide RNA interference (RNAi) screen aimed at detecting cellular host-factors that can modify prion propagation. We exposed prion-infected cells in high-density microplates to 35,364 ternary pools of 52,746 siRNAs targeting 17,582 genes representing the majority of the mouse protein-coding transcriptome. We identified 1,191 modulators of prion propagation. While 1,151 modified the expression of both the pathological prion protein, PrPSc , and its cellular counterpart, PrPC , 40 genes selectively affected PrPSc . Of the latter 40 genes, 20 augmented prion production when suppressed. A prominent limiter of prion propagation was the heterogeneous nuclear ribonucleoprotein Hnrnpk. Psammaplysene A (PSA), which binds Hnrnpk, reduced prion levels in cultured cells and protected them from cytotoxicity. PSA also reduced prion levels in infected cerebellar organotypic slices and alleviated locomotor deficits in prion-infected Drosophila melanogaster expressing ovine PrPC . Hence, genome-wide QUIPPER-based perturbations can discover actionable cellular pathways involved in prion propagation. Further, the unexpected identification of a prion-controlling ribonucleoprotein suggests a role for RNA in the generation of infectious prions.
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Affiliation(s)
- Merve Avar
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | - Daniel Heinzer
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | - Alana M Thackray
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - Yingjun Liu
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | | | - Stefano Sellitto
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | - Elke Schaper
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | - Daniel P Pease
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | - Jiang‐An Yin
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | | | - Marc Emmenegger
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | - Marco Losa
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | - Andra Chincisan
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | - Simone Hornemann
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
| | | | - Raymond Bujdoso
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - Adriano Aguzzi
- Institute of NeuropathologyUniversity of ZurichZurichSwitzerland
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Abstract
Prions were initially discovered in studies of scrapie, a transmissible neurodegenerative disease (ND) of sheep and goats thought to be caused by slow viruses. Once scrapie was transmitted to rodents, it was discovered that the scrapie pathogen resisted inactivation by procedures that modify nucleic acids. Eventually, this novel pathogen proved to be a protein of 209 amino acids, which is encoded by a chromosomal gene. After the absence of a nucleic acid within the scrapie agent was established, the mechanism of infectivity posed a conundrum and eliminated a hypothetical virus. Subsequently, the infectious scrapie prion protein (PrPSc) enriched for β-sheet was found to be generated from the cellular prion protein (PrPC) that is predominantly α-helical. The post-translational process that features in nascent prion formation involves a templated conformational change in PrPC that results in an infectious copy of PrPSc. Thus, prions are proteins that adopt alternative conformations, which are self-propagating and found in organisms ranging from yeast to humans. Prions have been found in both Alzheimer's (AD) and Parkinson's (PD) diseases. Mutations in APP and α-synuclein genes have been shown to cause familial AD and PD. Recently, AD was found to be a double prion disorder: both Aβ and tau prions feature in this ND. Increasing evidence argues for α-synuclein prions as the cause of PD, multiple system atrophy, and Lewy body dementia.
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Ascari LM, Rocha SC, Gonçalves PB, Vieira TCRG, Cordeiro Y. Challenges and Advances in Antemortem Diagnosis of Human Transmissible Spongiform Encephalopathies. Front Bioeng Biotechnol 2020; 8:585896. [PMID: 33195151 PMCID: PMC7606880 DOI: 10.3389/fbioe.2020.585896] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/28/2020] [Indexed: 12/18/2022] Open
Abstract
Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, arise from the structural conversion of the monomeric, cellular prion protein (PrPC) into its multimeric scrapie form (PrPSc). These pathologies comprise a group of intractable, rapidly evolving neurodegenerative diseases. Currently, a definitive diagnosis of TSE relies on the detection of PrPSc and/or the identification of pathognomonic histological features in brain tissue samples, which are usually obtained postmortem or, in rare cases, by brain biopsy (antemortem). Over the past two decades, several paraclinical tests for antemortem diagnosis have been developed to preclude the need for brain samples. Some of these alternative methods have been validated and can provide a probable diagnosis when combined with clinical evaluation. Paraclinical tests include in vitro cell-free conversion techniques, such as the real-time quaking-induced conversion (RT-QuIC), as well as immunoassays, electroencephalography (EEG), and brain bioimaging methods, such as magnetic resonance imaging (MRI), whose importance has increased over the years. PrPSc is the main biomarker in TSEs, and the RT-QuIC assay stands out for its ability to detect PrPSc in cerebrospinal fluid (CSF), olfactory mucosa, and dermatome skin samples with high sensitivity and specificity. Other biochemical biomarkers are the proteins 14-3-3, tau, neuron-specific enolase (NSE), astroglial protein S100B, α-synuclein, and neurofilament light chain protein (NFL), but they are not specific for TSEs. This paper reviews the techniques employed for definite diagnosis, as well as the clinical and paraclinical methods for possible and probable diagnosis, both those in use currently and those no longer employed. We also discuss current criteria, challenges, and perspectives for TSE diagnosis. An early and accurate diagnosis may allow earlier implementation of strategies to delay or stop disease progression.
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Affiliation(s)
- Lucas M. Ascari
- Faculty of Pharmacy, Pharmaceutical Biotechnology Department, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Stephanie C. Rocha
- Faculty of Pharmacy, Pharmaceutical Biotechnology Department, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Priscila B. Gonçalves
- Faculty of Pharmacy, Pharmaceutical Biotechnology Department, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Tuane C. R. G. Vieira
- Institute of Medical Biochemistry Leopoldo de Meis, National Institute of Science and Technology for Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Yraima Cordeiro
- Faculty of Pharmacy, Pharmaceutical Biotechnology Department, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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De Novo Generation of a Unique Cervid Prion Strain Using Protein Misfolding Cyclic Amplification. mSphere 2017; 2:mSphere00372-16. [PMID: 28144628 PMCID: PMC5266495 DOI: 10.1128/msphere.00372-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 01/11/2017] [Indexed: 11/29/2022] Open
Abstract
CWD is the only known TSE that affects free-ranging wildlife, specifically cervids such as elk, deer, moose, caribou, and reindeer. CWD has become endemic in both free-ranging and captive herds in North America, South Korea, and, most recently, northern Europe. The prion research community continues to debate the origins of CWD. Original foci of CWD emergence in Colorado and Wyoming coincident with the sheep TSE scrapie suggest that scrapie prions may have adapted to cervids to cause CWD. However, emerging evidence supports the idea that cervid PrPC may be more prone to misfolding to the pathological isoform. Here we test the hypothesis that cervid PrPC can spontaneously misfold to create de novo prions. Whether CWD can arise spontaneously as a sporadic TSE or represents a new TSE caused by cervid-adapted scrapie prions profoundly impacts surveillance and mitigation strategies. Substantial evidence supports the hypothesis that prions are misfolded, infectious, insoluble, and protease-resistant proteins (PrPRES) devoid of instructional nucleic acid that cause transmissible spongiform encephalopathies (TSEs). Protein misfolding cyclic amplification (PMCA) has provided additional evidence that PrPRes acts as a template that can convert the normal cellular prion protein (PrPC) present in uninfected normal brain homogenate (NBH) into the infectious misfolded PrPRES isoform. Human PrPC has been shown to spontaneously convert to a misfolded pathological state causing sporadic Creutzfeldt-Jakob disease (sCJD). Several investigators have reported spontaneous generation of prions by in vitro assays, including PMCA. Here we tested the rate of de novo generation of cervid prions in our laboratory using our standard PMCA protocol and NBH from transgenic mice expressing cervid PrPC (TgCerPrP mice). We generated de novo prions in rounds 4, 5, and 7 at low cumulative rates of 1.6, 5.0, and 6.7%, respectively. The prions caused infectious chronic wasting disease (CWD) upon inoculation into normal uninfected TgCerPrP mice and displayed unique biochemical characteristics compared to other cervid prion strains. We conclude that PMCA of cervid PrPC from normal brain homogenate spontaneously generated a new cervid prion strain. These data support the potential for cervids to develop sporadic CWD. IMPORTANCE CWD is the only known TSE that affects free-ranging wildlife, specifically cervids such as elk, deer, moose, caribou, and reindeer. CWD has become endemic in both free-ranging and captive herds in North America, South Korea, and, most recently, northern Europe. The prion research community continues to debate the origins of CWD. Original foci of CWD emergence in Colorado and Wyoming coincident with the sheep TSE scrapie suggest that scrapie prions may have adapted to cervids to cause CWD. However, emerging evidence supports the idea that cervid PrPC may be more prone to misfolding to the pathological isoform. Here we test the hypothesis that cervid PrPC can spontaneously misfold to create de novo prions. Whether CWD can arise spontaneously as a sporadic TSE or represents a new TSE caused by cervid-adapted scrapie prions profoundly impacts surveillance and mitigation strategies. Podcast: A podcast concerning this article is available.
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Prion protein-specific antibodies-development, modes of action and therapeutics application. Viruses 2014; 6:3719-37. [PMID: 25275428 PMCID: PMC4213558 DOI: 10.3390/v6103719] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/22/2014] [Accepted: 09/23/2014] [Indexed: 12/21/2022] Open
Abstract
Prion diseases or Transmissible Spongiform Encephalopathies (TSEs) are lethal neurodegenerative disorders involving the misfolding of the host encoded cellular prion protein, PrPC. This physiological form of the protein is expressed throughout the body, and it reaches the highest levels in the central nervous system where the pathology occurs. The conversion into the pathogenic isoform denoted as prion or PrPSc is the key event in prion disorders. Prominent candidates for the treatment of prion diseases are antibodies and their derivatives. Anti-PrPC antibodies are able to clear PrPSc from cell culture of infected cells. Furthermore, application of anti-PrPC antibodies suppresses prion replication in experimental animal models. Major drawbacks of immunotherapy are immune tolerance, the risks of neurotoxic side effects, limited ability of compounds to cross the blood-brain barrier and their unfavorable pharmacokinetic. The focus of this review is to recapitulate the current understanding of the molecular mechanisms for antibody mediated anti-prion activity. Although relevant for designing immunotherapeutic tools, the characterization of key antibody parameters shaping the molecular mechanism of the PrPC to PrPSc conversion remains elusive. Moreover, this review illustrates the various attempts towards the development of anti-PrP antibody compounds and discusses therapeutic candidates that modulate PrP expression.
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Molecular dynamics studies on the NMR and X-ray structures of rabbit prion proteins. J Theor Biol 2013; 342:70-82. [PMID: 24184221 DOI: 10.1016/j.jtbi.2013.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 08/25/2013] [Accepted: 10/09/2013] [Indexed: 12/27/2022]
Abstract
Prion diseases, traditionally referred to as transmissible spongiform encephalopathies (TSEs), are invariably fatal and highly infectious neurodegenerative diseases that affect a wide variety of mammalian species, manifesting as scrapie in sheep and goats, bovine spongiform encephalopathy (BSE or mad-cow disease) in cattle, chronic wasting disease in deer and elk, and Creutzfeldt-Jakob diseases, Gerstmann-Sträussler-Scheinker syndrome, fatal familial insomnia, and kulu in humans, etc. These neurodegenerative diseases are caused by the conversion from a soluble normal cellular prion protein (PrP(C)) into insoluble abnormally folded infectious prions (PrP(Sc)), and the conversion of PrP(C) to PrP(Sc) is believed to involve conformational change from a predominantly α-helical protein to one rich in β-sheet structure. Such a conformational change may be amenable to study by molecular dynamics (MD) techniques. For rabbits, classical studies show that they have a low susceptibility to be infected by PrP(Sc), but recently it was reported that rabbit prions can be generated through saPMCA (serial automated Protein Misfolding Cyclic Amplification) in vitro and the rabbit prion is infectious and transmissible. In this paper, we first do a detailed survey on the research advances of rabbit prion protein (RaPrP) and then we perform MD simulations on the NMR and X-ray molecular structures of rabbit prion protein wild-type and mutants. The survey shows to us that rabbits were not challenged directly in vivo with other known prion strains and the saPMCA result did not pass the test of the known BSE strain of cattle. Thus, we might still look rabbits as a prion resistant species. MD results indicate that the three α-helices of the wild-type are stable under the neutral pH environment (but under low pH environment the three α-helices have been unfolded into β-sheets), and the three α-helices of the mutants (I214V and S173N) are unfolded into rich β-sheet structures under the same pH environment. In addition, we found an interesting result that the salt bridges such as ASP201-ARG155, ASP177-ARG163 contribute greatly to the structural stability of RaPrP.
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Vascellari S, Orrù CD, Hughson AG, King D, Barron R, Wilham JM, Baron GS, Race B, Pani A, Caughey B. Prion seeding activities of mouse scrapie strains with divergent PrPSc protease sensitivities and amyloid plaque content using RT-QuIC and eQuIC. PLoS One 2012; 7:e48969. [PMID: 23139828 PMCID: PMC3489776 DOI: 10.1371/journal.pone.0048969] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 10/02/2012] [Indexed: 11/18/2022] Open
Abstract
Different transmissible spongiform encephalopathy (TSE)-associated forms of prion protein (e.g. PrPSc) can vary markedly in ultrastructure and biochemical characteristics, but each is propagated in the host. PrPSc propagation involves conversion from its normal isoform, PrPC, by a seeded or templated polymerization mechanism. Such a mechanism is also the basis of the RT-QuIC and eQuIC prion assays which use recombinant PrP (rPrPSen) as a substrate. These ultrasensitive detection assays have been developed for TSE prions of several host species and sample tissues, but not for murine models which are central to TSE pathogenesis research. Here we have adapted RT-QuIC and eQuIC to various murine prions and evaluated how seeding activity depends on glycophosphatidylinositol (GPI) anchoring and the abundance of amyloid plaques and protease-resistant PrPSc (PrPRes). Scrapie brain dilutions up to 10−8 and 10−13 were detected by RT-QuIC and eQuIC, respectively. Comparisons of scrapie-affected wild-type mice and transgenic mice expressing GPI anchorless PrP showed that, although similar concentrations of seeding activity accumulated in brain, the heavily amyloid-laden anchorless mouse tissue seeded more rapid reactions. Next we compared seeding activities in the brains of mice with similar infectivity titers, but widely divergent PrPRes levels. For this purpose we compared the 263K and 139A scrapie strains in transgenic mice expressing P101L PrPC. Although the brains of 263K-affected mice had little immunoblot-detectable PrPRes, RT-QuIC indicated that seeding activity was comparable to that associated with a high-PrPRes strain, 139A. Thus, in this comparison, RT-QuIC seeding activity correlated more closely with infectivity than with PrPRes levels. We also found that eQuIC, which incorporates a PrPSc immunoprecipitation step, detected seeding activity in plasma from wild-type and anchorless PrP transgenic mice inoculated with 22L, 79A and/or RML scrapie strains. Overall, we conclude that these new mouse-adapted prion seeding assays detect diverse types of PrPSc.
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Affiliation(s)
- Sarah Vascellari
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Christina D. Orrù
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Andrew G. Hughson
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Declan King
- Division of Neurobiology, The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, United Kingdom
| | - Rona Barron
- Division of Neurobiology, The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, United Kingdom
| | - Jason M. Wilham
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Gerald S. Baron
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Brent Race
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Alessandra Pani
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Byron Caughey
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
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Kang HE, Weng CC, Saijo E, Saylor V, Bian J, Kim S, Ramos L, Angers R, Langenfeld K, Khaychuk V, Calvi C, Bartz J, Hunter N, Telling GC. Characterization of conformation-dependent prion protein epitopes. J Biol Chem 2012; 287:37219-32. [PMID: 22948149 PMCID: PMC3481321 DOI: 10.1074/jbc.m112.395921] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Whereas prion replication involves structural rearrangement of cellular prion protein (PrP(C)), the existence of conformational epitopes remains speculative and controversial, and PrP transformation is monitored by immunoblot detection of PrP(27-30), a protease-resistant counterpart of the pathogenic scrapie form (PrP(Sc)) of PrP. We now describe the involvement of specific amino acids in conformational determinants of novel monoclonal antibodies (mAbs) raised against randomly chimeric PrP. Epitope recognition of two mAbs depended on polymorphisms controlling disease susceptibility. Detection by one, referred to as PRC5, required alanine and asparagine at discontinuous mouse PrP residues 132 and 158, which acquire proximity when residues 126-218 form a structured globular domain. The discontinuous epitope of glycosylation-dependent mAb PRC7 also mapped within this domain at residues 154 and 185. In accordance with their conformational dependence, tertiary structure perturbations compromised recognition by PRC5, PRC7, as well as previously characterized mAbs whose epitopes also reside in the globular domain, whereas conformation-independent epitopes proximal or distal to this region were refractory to such destabilizing treatments. Our studies also address the paradox of how conformational epitopes remain functional following denaturing treatments and indicate that cellular PrP and PrP(27-30) both renature to a common structure that reconstitutes the globular domain.
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Affiliation(s)
- Hae-Eun Kang
- From the Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Chu Chun Weng
- the Integrated Biomedical Sciences Program, Department of Microbiology, Immunology, and Molecular Genetics, Department of Neurology, and Sanders Brown Center on Aging, University of Kentucky Medical Center, Lexington, Kentucky 40536
| | - Eri Saijo
- From the Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523, ,the Integrated Biomedical Sciences Program, Department of Microbiology, Immunology, and Molecular Genetics, Department of Neurology, and Sanders Brown Center on Aging, University of Kentucky Medical Center, Lexington, Kentucky 40536
| | - Vicki Saylor
- the Integrated Biomedical Sciences Program, Department of Microbiology, Immunology, and Molecular Genetics, Department of Neurology, and Sanders Brown Center on Aging, University of Kentucky Medical Center, Lexington, Kentucky 40536
| | - Jifeng Bian
- From the Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Sehun Kim
- From the Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Laylaa Ramos
- From the Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Rachel Angers
- the Integrated Biomedical Sciences Program, Department of Microbiology, Immunology, and Molecular Genetics, Department of Neurology, and Sanders Brown Center on Aging, University of Kentucky Medical Center, Lexington, Kentucky 40536
| | - Katie Langenfeld
- the Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska 68178, and
| | - Vadim Khaychuk
- From the Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Carla Calvi
- From the Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Jason Bartz
- the Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska 68178, and
| | - Nora Hunter
- the Roslin Institute, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, Scotland, United Kingdom
| | - Glenn C. Telling
- From the Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523, ,the Integrated Biomedical Sciences Program, Department of Microbiology, Immunology, and Molecular Genetics, Department of Neurology, and Sanders Brown Center on Aging, University of Kentucky Medical Center, Lexington, Kentucky 40536, , To whom correspondence should be addressed. Tel.: 970-491-2968; E-mail:
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Diaz-Espinoza R, Mukherjee A, Soto C. Kosmotropic anions promote conversion of recombinant prion protein into a PrPSc-like misfolded form. PLoS One 2012; 7:e31678. [PMID: 22347503 PMCID: PMC3276510 DOI: 10.1371/journal.pone.0031678] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 01/11/2012] [Indexed: 11/18/2022] Open
Abstract
Prions are self-propagating proteins involved in transmissible spongiform encephalopaties in mammals. An aberrant conformation with amyloid-like features of a cell surface protein, termed prion protein (PrP), is thought to be the essential component of the infectious particle, though accessory co-factor molecules such as lipids and nucleotides may be involved. The cellular co-factors and environmental conditions implicated in PrP misfolding are not completely understood. To address this issue, several studies have been done inducing misfolding of recombinant PrP (recPrP) into classical amyloid structures using partially denaturing conditions. In this work, we report that misfolding of recPrP into PrP(Sc)-like aggregates can be induced by simply incubating the protein in the presence of kosmotropic salts at concentrations that are known to retain or increase the stability of the protein. We used a simple experimental reaction (protein, buffer and salts) submitted to agitation/incubation cycles at physiological temperature and pH. The formation of protease resistant-recPrP was time and salt-concentration dependent and required the presence of kosmotropic anions such as F(-) or SO(4)(-2). The molecular weights of the protease resistant recPrP fragments are reminiscent of those found in degradation assays of bona fide PrP(Sc). The aggregates also exhibited PrP(Sc)-like ultrastructural features including rod-shape morphology under electron microscope, high beta-sheet content and thioflavin-T positive signal. The formation of recPrP aggregates with PrP(Sc) biochemical features under conditions closer to physiological in the absence of organic co-factor molecules provides a simple setup that may prove helpful to understand the molecular mechanism of PrP misfolding.
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Affiliation(s)
- Rodrigo Diaz-Espinoza
- Department of Neurology, Mitchell Center for Alzheimer's Disease and Related Brain Disorders, University of Texas Houston Medical School, Houston, Texas, United States of America
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Abhisek Mukherjee
- Department of Neurology, Mitchell Center for Alzheimer's Disease and Related Brain Disorders, University of Texas Houston Medical School, Houston, Texas, United States of America
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Claudio Soto
- Department of Neurology, Mitchell Center for Alzheimer's Disease and Related Brain Disorders, University of Texas Houston Medical School, Houston, Texas, United States of America
- * E-mail:
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Abstract
Although prion diseases, such as Creutzfeldt-Jakob disease (CJD) in humans and scrapie in sheep, have long been recognized, our understanding of their epidemiology and pathogenesis is still in its early stages. Progress is hampered by the lengthy incubation periods and the lack of effective ways of monitoring and characterizing these agents. Protease-resistant conformers of the prion protein (PrP), known as the "scrapie form" (PrP(Sc)), are used as disease markers, and for taxonomic purposes, in correlation with clinical, pathological, and genetic data. In humans, prion diseases can arise sporadically (sCJD) or genetically (gCJD and others), caused by mutations in the PrP-gene (PRNP), or as a foodborne infection, with the agent of bovine spongiform encephalopathy (BSE) causing variant CJD (vCJD). Person-to-person spread of human prion disease has only been known to occur following cannibalism (kuru disease in Papua New Guinea) or through medical or surgical treatment (iatrogenic CJD, iCJD). In contrast, scrapie in small ruminants and chronic wasting disease (CWD) in cervids behave as infectious diseases within these species. Recently, however, so-called atypical forms of prion diseases have been discovered in sheep (atypical/Nor98 scrapie) and in cattle, BSE-H and BSE-L. These maladies resemble sporadic or genetic human prion diseases and might be their animal equivalents. This hypothesis also raises the significant public health question of possible epidemiological links between these diseases and their counterparts in humans.
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Stanker LH, Serban AV, Cleveland E, Hnasko R, Lemus A, Safar J, DeArmond SJ, Prusiner SB. Conformation-dependent high-affinity monoclonal antibodies to prion proteins. THE JOURNAL OF IMMUNOLOGY 2010; 185:729-37. [PMID: 20530267 DOI: 10.4049/jimmunol.0902930] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prion diseases are fatal, neurodegenerative illnesses caused by the accumulation of PrP(Sc), an aberrantly folded isoform of the normal, cellular prion protein. Detection of PrP(Sc) commonly relies on immunochemical methods, a strategy hampered by the lack of Abs specific for this disease-causing isoform. In this article, we report the generation of eight mAbs against prion protein (PrP) following immunization of Prnp-null mice with rPrP. The eight mAbs exhibited distinct differential binding to cellular prion protein and PrP(Sc) from different species as well as PrP-derived synthetic peptides. Five of the eight mAbs exhibited binding to discontinuous PrP epitopes, all of which were disrupted by the addition of 2-ME or DTT, which reduced the single disulfide bond found in PrP. One mAb F20-29 reacted only with human PrP, whereas the F4-31 mAb bound bovine PrP; the K(D) values for mAbs F4-31 and F20-29 were ~500 pM. Binding of all five conformation-dependent mAbs to PrP was inhibited by 2-ME in ELISA, Western blots, and histoblots. One conformation-dependent mAb F4-31 increased the sensitivity of an ELISA-based test by nearly 500-fold when it was used as the capture Ab. These new conformation-dependent mAbs were found to be particularly useful in histoblotting studies, in which the low backgrounds after treatment with 2-ME created unusually high signal-to-noise ratios.
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Affiliation(s)
- Larry H Stanker
- Foodborne Contaminants Research Unit, U.S. Department of Agriculture Agricultural Research Service, Albany, CA 94710, USA
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13
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Liu YS, Ding YZ, Zhang J, Chen HT, Zhu XL, Cai XP, Liu XT, Xie QG. Simple method of monoclonal antibody production against mammalian cellular prion protein. Hybridoma (Larchmt) 2010; 29:37-43. [PMID: 20199150 DOI: 10.1089/hyb.2009.0058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Monoclonal antibodies (MAbs) against prion protein (PrP) are powerful tools for diagnosis and research in transmissible spongiform encephalopathies. Ten MAbs to recombinant/native cellular PrP (PrPc) in mammals were prepared with a simple method and identified in detail. Normal BALB/c mice were immunized with the recombinant bovine mature PrP (rbomPrP) and PrP27-30 (rboPrP27-30) expressed in Escherichia coli. The immunized splenocytes were fused with SP2/0 mouse myeloma cells, and positive hybridomas were selected by indirect enzyme-linked immunosorbent assay (ELISA). The characterizations of these MAbs, such as Ig, Ig subclass, titer, affinity index, specificity, epitopes recognized, and binding to recombinant/native PrPc of cattle, sheep, or human beings, were evaluated by Western blotting and indirect or sandwich ELISA. Ten MAbs could be divided into five groups depending on the results of indirect ELISA additivity test and their reaction to E. coli-expressed truncated-PrPs. Isotyping of the MAbs revealed that they belong to IgG1, IgG2a, and IgG2b subclass. Their indirect ELISA titers were between 10(3) and 10(6). Affinity constants were between 10(9) and 10(12) M(-1). Ten MAbs specifically reacted with the rbomPrP, without binding to prion-like protein Doppel and the lysates of E. coli. These MAbs could also respond to the recombinant mature PrP (rmPrP) of sheep and human beings. Also of interest was the ability of the MAbs to bind with dimer of rmPrP and PrP extracted from the brain tissue of cattle or sheep. We conclude that anti-PrP MAbs successfully prepared with a simple method could potentially be useful in mammalian prion research.
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Affiliation(s)
- Yong-sheng Liu
- Key Laboratory of Animal Virology of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
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14
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In vitro infectivity assay for prion titration for application to the evaluation of the prion removal capacity of biological products manufacturing processes. J Virol Methods 2010; 164:1-6. [DOI: 10.1016/j.jviromet.2009.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 10/08/2009] [Accepted: 10/13/2009] [Indexed: 11/30/2022]
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15
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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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16
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Abstract
Prions are infectious proteins that cause fatal neurodegenerative diseases. Because astrocytic gliosis marked by the deposition of fibrils composed of GFAP is a prominent feature of prion disease, we asked whether GFAP might be used as a surrogate marker for prions. To interrogate this posit, we inoculated prions into transgenic (Tg) mice expressing luciferase (luc) under the GFAP gene (Gfap) promoter, denoted Tg(Gfap-luc) mice. Weekly noninvasive, bioluminescence imaging (BLI) detected an increase in light emitted from the brains of Tg(Gfap-luc) mice at approximately 55 d after inoculation and approximately 62 d before neurologic deficits appeared. To determine whether BLI could be used as a proxy bioassay for prion infectivity, we performed endpoint titrations of prions in Tg(Gfap-luc) mice. BLI bioassays were as or more sensitive than those determined by the onset of neurological dysfunction, and were completed in approximately half the time. Our studies argue that BLI is likely to be a suitable surrogate for measuring prion infectivity, and might be useful in the study of Tg mouse models for other neurodegenerative illnesses.
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17
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Di Bari MA, Chianini F, Vaccari G, Esposito E, Conte M, Eaton SL, Hamilton S, Finlayson J, Steele PJ, Dagleish MP, Reid HW, Bruce M, Jeffrey M, Agrimi U, Nonno R. The bank vole (Myodes glareolus) as a sensitive bioassay for sheep scrapie. J Gen Virol 2009; 89:2975-2985. [PMID: 19008382 DOI: 10.1099/vir.0.2008/005520-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite intensive studies on sheep scrapie, a number of questions remain unanswered, such as the natural mode of transmission and the amount of infectivity which accumulates in edible tissues at different stages of scrapie infection. Studies using the mouse model proved to be useful for recognizing scrapie strain diversity, but the low sensitivity of mice to some natural scrapie isolates hampered further investigations. To investigate the sensitivity of bank voles (Myodes glareolus) to scrapie, we performed end-point titrations from two unrelated scrapie sources. Similar titres [10(5.5) ID50 U g(-1) and 10(5.8) ID50 U g(-1), both intracerebrally (i.c.)] were obtained, showing that voles can detect infectivity up to 3-4 orders of magnitude lower when compared with laboratory mice. We further investigated the relationships between PrPSc molecular characteristics, strain and prion titre in the brain and tonsil of the same scrapie-affected sheep. We found that protease-resistant PrPSc fragments (PrPres) from brain and tonsil had different molecular features, but induced identical disease phenotypes in voles. The infectivity titre of the tonsil estimated by incubation time assay was 10(4.8) i.c. ID50 U g(-1), i.e. fivefold less than the brain. This compared well with the relative PrPres content, which was 8.8-fold less in tonsil than in brain. Our results suggest that brain and tonsil harboured the same prion strain showing different glycoprofiles in relation to the different cellular/tissue types in which it replicated, and that a PrPSc-based estimate of scrapie infectivity in sheep tissues could be achieved by combining sensitive PrPres detection methods and bioassay in voles.
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Affiliation(s)
- Michele Angelo Di Bari
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Francesca Chianini
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Gabriele Vaccari
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Elena Esposito
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Michela Conte
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Samantha L Eaton
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Scott Hamilton
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Jeanie Finlayson
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Philip J Steele
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Mark P Dagleish
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Hugh W Reid
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Moira Bruce
- Neuropathogenesis Unit, Roslin Institute, Ogston Building, West Mains Road, Edinburgh EH9 3JF, UK
| | - Martin Jeffrey
- Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Umberto Agrimi
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Romolo Nonno
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
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18
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Graether SP, Sykes BD. Structural characterization of amyloidotic antifreeze protein fibrils and intermediates. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:1030-1033. [PMID: 19697237 DOI: 10.1080/15287390903084272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The propagation and detrimental effects of prion disease are thought to be associated with the amyloid-like prion fibrils or with other misfolded structures known as beta-oligomers. The freezing and thawing of high concentrations of an antifreeze protein result in fibrils that have morphological and structural properties similar to those of amyloid. The method to produce these amyloid-like fibrils is expanded upon in this study. Data showed that the C-terminal end of the protein retains its alpha-helical character even in the amyloid state, and that changing the pH of the protein solution from 4 to 8 resulted in gels that resemble the beta-oligomeric form. These interim results provide the conditions for further elucidating the structure of these fibrils and their intermediate states.
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Affiliation(s)
- Steffen P Graether
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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19
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The POM monoclonals: a comprehensive set of antibodies to non-overlapping prion protein epitopes. PLoS One 2008; 3:e3872. [PMID: 19060956 PMCID: PMC2592702 DOI: 10.1371/journal.pone.0003872] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2008] [Accepted: 11/06/2008] [Indexed: 01/14/2023] Open
Abstract
PrPSc, a misfolded and aggregated form of the cellular prion protein PrPC, is the only defined constituent of the transmissible agent causing prion diseases. Expression of PrPC in the host organism is necessary for prion replication and for prion neurotoxicity. Understanding prion diseases necessitates detailed structural insights into PrPC and PrPSc. Towards this goal, we have developed a comprehensive collection of monoclonal antibodies denoted POM1 to POM19 and directed against many different epitopes of mouse PrPC. Three epitopes are located within the N-terminal octarepeat region, one is situated within the central unstructured region, and four epitopes are discontinuous within the globular C-proximal domain of PrPC. Some of these antibodies recognize epitopes that are resilient to protease digestion in PrPSc. Other antibodies immunoprecipitate PrPC, but not PrPSc. A third group was found to immunoprecipitate both PrP isoforms. Some of the latter antibodies could be blocked with epitope-mimicking peptides, and incubation with an excess of these peptides allowed for immunochromatography of PrPC and PrPSc. Amino-proximal antibodies were found to react with repetitive PrPC epitopes, thereby vastly increasing their avidity. We have also created functional single-chain miniantibodies from selected POMs, which retained the binding characteristics despite their low molecular mass. The POM collection, thus, represents a unique set of reagents allowing for studies with a variety of techniques, including western blotting, ELISA, immunoprecipitation, conformation-dependent immunoassays, and plasmon surface plasmon resonance-based assays.
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20
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Falsig J, Nilsson KP, Knowles TPJ, Aguzzi A. Chemical and biophysical insights into the propagation of prion strains. HFSP JOURNAL 2008; 2:332-41. [PMID: 19436493 DOI: 10.2976/1.2990786] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Indexed: 01/21/2023]
Abstract
Transmissible spongiform encephalopathies (TSEs) are lethal infectious neurodegenerative diseases. TSEs are caused by prions, infectious agents lacking informational nucleic acids, and possibly identical with higher-order aggregates of the cellular glycolipoprotein PrP(C). Prion strains are derived from TSE isolates that, even after inoculation into genetically identical hosts, cause disease with distinct patterns of protein aggregate deposition, incubation times, morphology of the characteristic brain damage, and cellular tropism. Most of these traits are relatively stable across serial passages. Here we review current techniques for studying prion strain differences in vivo and in cells, and discuss the strain phenomena in the general context of the knowledge gained from modeling prion fibril growth in vitro and in simple organisms.
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21
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Greil CS, Vorberg IM, Ward AE, Meade-White KD, Harris DA, Priola SA. Acute cellular uptake of abnormal prion protein is cell type and scrapie-strain independent. Virology 2008; 379:284-93. [PMID: 18692214 DOI: 10.1016/j.virol.2008.07.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 05/12/2008] [Accepted: 07/02/2008] [Indexed: 11/17/2022]
Abstract
Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases that include Creutzfeldt-Jakob disease, bovine spongiform encephalopathy and sheep scrapie. Although one of the earliest events during TSE infection is the cellular uptake of protease resistant prion protein (PrP-res), this process is poorly understood due to the difficulty of clearly distinguishing input PrP-res from either PrP-res or protease-sensitive PrP (PrP-sen) made by the cell. Using PrP-res tagged with a unique antibody epitope, we examined PrP-res uptake in neuronal and fibroblast cells exposed to three different mouse scrapie strains. PrP-res uptake was rapid and independent of scrapie strain, cell type, or cellular PrP expression, but occurred in only a subset of cells and was influenced by PrP-res preparation and aggregate size. Our results suggest that PrP-res aggregate size, the PrP-res microenvironment, and/or host cell-specific factors can all influence whether or not a cell takes up PrP-res following exposure to TSE infectivity.
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Affiliation(s)
- Christopher S Greil
- Rocky Mountain Laboratories, Laboratory of Persistent Viral Diseases, NIAID, NIH, 903 S. 4th Street, Hamilton, Montana 59840, USA
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22
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New insights into early sequential PrPsc accumulation in scrapie infected mouse brain evidenced by the use of streptomycin sulfate. Histochem Cell Biol 2008; 129:643-50. [DOI: 10.1007/s00418-008-0382-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2008] [Indexed: 10/22/2022]
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23
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McKinley MP, Lingappa VR, Prusiner SB. Developmental regulation of prion protein mRNA in brain. CIBA FOUNDATION SYMPOSIUM 2007; 135:101-16. [PMID: 2900716 DOI: 10.1002/9780470513613.ch7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
During development of the hamster brain, synthesis of the cellular isoform of the scrapie prion protein (PrPC) was found to be regulated. Low levels of PrP poly(A)+ mRNA were detectable one day after birth. PrP poly(A)+ mRNA reached maximal levels between 10 and 20 days post-partum; thereafter, no change in its level could be detected at ages up to 13 months. In contrast, myelin basic protein poly(A)+ mRNA was shown to reach maximal levels by 30 days of age and thereafter steadily declined in adult brain. Using monospecific PrP antisera, immunoprecipitable cell-free translation products were detected at low levels two days after birth and progressively increased up to 10 days of age. How the PrP mRNA participates in brain development and its function in scrapie prion infection are being investigated.
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Affiliation(s)
- M P McKinley
- Department of Neurology, University of California, San Francisco 94143
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24
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Prusiner SB, Stahl N, DeArmond SJ. Novel mechanisms of degeneration of the central nervous system--prion structure and biology. CIBA FOUNDATION SYMPOSIUM 2007; 135:239-60. [PMID: 2900720 DOI: 10.1002/9780470513613.ch16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Prion is a term for the novel infectious agents which cause scrapie and Creutzfeldt-Jakob disease; these infectious pathogens are composed largely, if not entirely, of prion protein (PrP) molecules. No prion-specific polynucleotide has been identified. Considerable evidence indicates that PrP 27-30 is required for and inseparable from scrapie infectivity. PrP 27-30 is derived from a larger protein, denoted PrPSc. A cellular isoform, designated PrPC, and PrPSc are both encoded by a single copy chromosomal gene and both proteins appear to be translated from the same 2.1 kb mRNA. Monoclonal antibodies to PrP 27-30 as well as antisera to PrP synthetic peptides, react with both PrPC and PrPSc, establishing the relatedness of these proteins. PrPC is completely digested by proteinase K; PrPSc is converted to PrP 27-30 under the same conditions. Detergent extraction of microsomal membranes isolated from scrapie-infected hamster brains solubilizes PrPC but induces PrPSc to polymerize into amyloid rods. This procedure allows separation of the two prion protein isoforms and the demonstration that PrPSc accumulates during scrapie infection while the level of PrPC does not change. The prion amyloid rods generated by detergent extraction are identical morphologically, except for length, to extracellular collections of prion amyloid filaments which form plaques in scrapie- and CJD-infected brains. The prion amyloid plaques stain with antibodies to PrP 27-30 and PrP peptides. Prion rods composed of PrP 27-30 dissociate into phospholipid vesicles with full retention of scrapie infectivity. The murine PrP gene (Prn-p) is linked to the Prn-i gene, which controls the length of the scrapie incubation period. Prolonged incubation times are a cardinal feature of scrapie and CJD. While the central role of PrPSc in scrapie pathogenesis is well established, the chemical and conformational differences between PrPC and PrPSc are unknown but presumably arise from post-translational events.
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Affiliation(s)
- S B Prusiner
- Department of Neurology, University of California, San Francisco 94143
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25
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Gabizon R, McKinley MP, Prusiner SB. Properties of scrapie prion proteins in liposomes and amyloid rods. CIBA FOUNDATION SYMPOSIUM 2007; 135:182-96. [PMID: 2900719 DOI: 10.1002/9780470513613.ch12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The scrapie prion protein (PrP 27-30) has been demonstrated to be required for infectivity. Aggregates of PrP 27-30 form insoluble amyloid rods which resist dissociation by non-denaturing detergents. Mixtures of the detergent cholate and phospholipids were found to solubilize PrP 27-30 with full retention of scrapie prion infectivity. No evidence for a prion-associated nucleic acid could be found when the phospholipid vesicles with PrP 27-30 were digested with nucleases and Zn2+. Under digestion conditions which allowed hydrolysis of exogenous nucleic acids, no diminution of prion infectivity was observed. Tobacco mosaic virions added to the liposomes at a concentration 100 times lower than the scrapie prion titre could be seen by electron microscopy. These studies indicate that there is no subpopulation of filamentous scrapie viruses hidden amongst the prion rods - indeed, they would have been observed among the liposomes. The partitioning of PrP 27-30 and scrapie infectivity into phospholipid vesicles argues for a central role of PrP 27-30 in scrapie pathogenesis and establishes that the prion amyloid rods are not essential for infectivity.
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Affiliation(s)
- R Gabizon
- Department of Neurology, University of California, San Francisco 94143
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26
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Masters CL, Beyreuther K. Neuropathology of unconventional virus infections: molecular pathology of spongiform change and amyloid plaque deposition. CIBA FOUNDATION SYMPOSIUM 2007; 135:24-36. [PMID: 3044707 DOI: 10.1002/9780470513613.ch3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To the triad of neuronal loss, gliosis and spongiform change as characteristic morphological changes associated with infection of the central nervous system, one can now add the presence of scrapie-associated filaments (SAF)/PrP rods. While the host's immune response is conspicuous by its absence, the vigorous astrocytic response is presumptive evidence of the host's ability to recognize and respond to the primary neuronal insult. We assume that the spongiform change and vacuolation of neurons are of fundamental importance in the pathogenesis of the disease, realizing that neither is specific or essential for the replication of the infectious agent. The topographical distribution of lesions is partly explained by the portal of entry and retrograde spread of the virus. The temporal progression of the lesions is more clearly determined by the host genes, best illustrated by studies of the incubation period. The molecular basis of the spongiform change is unknown but it is presumed to involve some disturbance of membrane metabolism. The recognition of PrP as a membrane glycoprotein invites proposals for its role in the development of these spongiform lesions. Extracellular amyloid occurs as plaques or congophilic angiopathy in some instances, and provides the best evidence that Alzheimer's disease (AD) is in some way related to the unconventional virus diseases. However, the protein subunit (A4) of the amyloid fibril in AD and its precursor are quite distinct from the PrP subunit which constitutes the amyloid fibril in these infectious diseases. It is still unclear whether the PrP subunit in the SAF has exactly the same composition as in the extracellular amyloid fibril. Our results suggest that only a fragment of the PrP molecule is the major constituent of the extracellular fibril. Since both PrP and A4 are derived from membrane glycoproteins, the elucidation of their normal function is likely to lead to a better understanding of the spongiform and amyloidogenic lesions in these diseases.
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Affiliation(s)
- C L Masters
- Department of Pathology, University of Western Australia, Perth
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27
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Abstract
The term prion has been used to describe self-replicating protein conformations that can convert other protein molecules of the same primary structure into its prion conformation. Several different proteins have now been found to exist as prions in Saccharomyces cerevisiae. Surprisingly, these heterologous prion proteins have a strong influence on each others' appearance and propagation, which may result from structural similarity between the prions. Both positive and negative effects of a prion on the de novo appearance of a heterologous prion have been observed in genetic studies. Other examples of reported interactions include mutual or unilateral inhibition and destabilization when two prions are present together in a single cell. In vitro work showing that one purified prion stimulates the conversion of a purified heterologous protein into a prion form, suggests that facilitation of de novo prion formation by heterologous prions in vivo is a result of a direct interaction between the prion proteins (a cross-seeding mechanism) and does not require other cellular components. However, other cellular structures, e.g., the cytoskeleton, may provide a scaffold for these interactions in vivo and chaperones can further facilitate or inhibit this process. Some negative prion-prion interactions may also occur via a direct interaction between the prion proteins. Another explanation is a competition between the prions for cellular factors involved in prion propagation or differential effects of chaperones stimulated by one prion on the heterologous prions.
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Affiliation(s)
- Irina L Derkatch
- Department of Microbiology, New York University School of Medicine, New York University Medical Center, New York, New York 10016, USA.
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28
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Ge F, Yao J, Fu X, Guo Z, Yan J, Zhang B, Zhang H, Tomozawa H, Miyazaki J, Sawashita J, Mori M, Higuchi K. Amyloidosis in transgenic mice expressing murine amyloidogenic apolipoprotein A-II (Apoa2c). J Transl Med 2007; 87:633-43. [PMID: 17468778 DOI: 10.1038/labinvest.3700559] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In mice, apolipoprotein A-II (apoA-II) self-associates to form amyloid fibrils (AApoAII) in an age-associated manner. We postulated that the two most important factors in apoA-II amyloidosis are the Apoa2(c) allele, which codes for the amyloidogenic protein APOA2C (Gln5, Ala38) and transmission of amyloid fibrils. To characterize further the contribution of the Apoa2(c) allele to amyloidogenesis and improve detection of amyloidogenic materials, we established transgenic mice that overexpress APOA2C protein under the cytomegalovirus (CMV) immediate early gene (CMV-IE) enhancer/chicken beta promoter. Compared to transgene negative (Tg(-/-)) mice that express apoA-II protein mainly in the liver, mice homozygous (Tg(+/+)) and heterozygous (Tg(+/-)) for the transgene express a high level of apoA-II protein in many tissues. They also have higher plasma concentrations of apoA-II, higher ratios of ApoA-II/apolipoprotein A-I (ApoA-I) and higher concentrations of high-density lipoprotein (HDL) cholesterol. Following injection of AApoAII fibrils into Tg(+/+) mice, amyloid deposition was observed in the testis, liver, kidney, heart, lungs, spleen, tongue, stomach and intestine but not in the brain. In Tg(+/+) mice, but not in Tg(-/-) mice, amyloid deposition was induced by injection of less than 10(-8) mug AApoAII fibrils. Furthermore, deposition in Tg(+/+) mice occurred more rapidly and to a greater extent than in Tg(-/-) mice. These studies indicate that increased levels of APOA2C protein lead to earlier and greater amyloid deposition and enhanced sensitivity to the transmission of amyloid fibrils in transgenic mice. This transgenic mouse model should prove valuable for studies of amyloidosis.
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Affiliation(s)
- Fengxia Ge
- Department of Aging Biology, Institute on Aging and Adaptation, Shinshu University Graduate School of Medicine, Matsumoto, Japan
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29
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Abstract
The resemblance between the discoveries that DNA is the basis of heredity and that prions are infectious proteins is remarkable. Though four decades separated these two discoveries, the biochemical methodologies and scientific philosophies that were employed are surprisingly similar. In both cases, bioassays available at the time that the projects were initiated proved to be inadequate to support purification studies. Improved bioassays allowed the transforming principle (TP) to be purified from pneumococci and prions from scrapie-infected hamster brains. Publications describing TP as composed of DNA prompted some scientists to contend that undetected proteins must contaminate TP enriched fractions. The simplicity of DNA was thought to prevent it from encoding genetic information. By the time prions were discovered, the genomes of all infectious pathogens including viruses, bacteria, fungi and parasites had been shown to be comprised of nucleic acids and so an antithetical refrain became widely echoed: DNA or RNA molecules must be hiding among the proteins of prions. Finding the unexpected and being asked to demonstrate unequivocally the absence of a possible contaminant represent uncanny parallels between the discoveries that DNA encodes the genotype and that prions are infectious proteins.
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Affiliation(s)
- Stanley B Prusiner
- Institute for Neurodegenerative Diseases, Department of Neurology, University of California, San Francisco, California 94143, USA
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30
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Gao C, Lei YJ, Han J, Shi Q, Chen L, Guo Y, Gao YJ, Chen JM, Jiang HY, Zhou W, Dong XP. Recombinant neural protein PrP can bind with both recombinant and native apolipoprotein E in vitro. Acta Biochim Biophys Sin (Shanghai) 2006; 38:593-601. [PMID: 16953297 DOI: 10.1111/j.1745-7270.2006.00209.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The most essential and crucial step during the pathogenesis of transmissible spongiform encephalopathy is the conformational change of cellular prion protein (PrP(C)) to pathologic isoform (PrP(Sc)). A lot of data revealed that caveolae-like domains (CLDs) in the cell surface were the probable place where the conversion of PrP proteins happened. Apolipoprotein E (ApoE) is an apolipoprotein which is considered to play an important role in the development of Alzheimer's disease and other neurodegenerative diseases by forming protein complex through binding to the receptor located in the clathrin-coated pits of the cell surface. In this study, a 914-bp cDNA sequence encoding human ApoE3 was amplified from neuroblastoma cell line SH-SY5Y. Three human ApoE isomers were expressed and purified from Escherichia coli. ApoE-specific antiserum was prepared by immunizing rabbits with the purified ApoE3. GST/His pull-down assay, immunoprecipitation and ELISA revealed that three full-length ApoE isomers interact with the recombinant full-length PrP protein in vitro. The regions corresponding to protein binding were mapped in the N-terminal segment of ApoE (amino acid 1-194) and the N-terminal of PrP (amino acid 23-90). Moreover, the recombinant PrP showed the ability to form a complex with the native ApoE from liver tissues. Our data provided direct evidence of molecular interaction between ApoE and PrP. It also supplied scientific clues for assessing the significance of CLDs on the surface of cellular membrane in the process of conformational conversion from PrP(C) to PrP(Sc) and probing into the pathogenesis of transmissible spongiform encephalopathy.
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Affiliation(s)
- Chen Gao
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China
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31
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Kobayashi Y, Kohno N, Wanibe S, Hirayasu K, Uemori H, Tagawa Y, Yokoyama T, Shinagawa M. A solid-phase immunoassay of protease-resistant prion protein with filtration blotting involving sodium dodecyl sulfate. Anal Biochem 2006; 349:218-28. [PMID: 16289444 DOI: 10.1016/j.ab.2005.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Accepted: 10/03/2005] [Indexed: 10/25/2022]
Abstract
The precise diagnosis for bovine spongiform encephalopathy (BSE) is crucial for preventing new transmission to humans. Several testing procedures are reported for determining protease-resistant prion protein in various tissues as a major hallmark of prion diseases such as BSE, scrapie, and Creutzfeldt-Jakob disease. However, contamination of materials from tissues or degradation of the specimens sometimes disturbs the accuracy of the assay. Here, we have developed a novel method for solid-phase immunoassay of the disease-specific conformational isoform, PrP(Sc), using filtration blotting of protein in the presence of sodium dodecyl sulfate (SDS) followed by a filtration-based immunoassay with a single anti-prion protein antibody, together with the improved fractionation procedure involving high concentrations of surfactant/detergent. The SDS/heat treatment renders unfolded PrP(Sc) quantitative retention on a polyvinylidene difluoride filter and allows enhancement of the analyte signal with immunodetection; thus, all of the tested specimens are determined with 100% accuracy. In addition, the immunoassay is completed in approximately 1h, indicating its usefulness not only for the screening of BSE specimens but probably also for the postmortem BSE diagnosis of fallen stock as the antibody recognizes the core part of PrP(Sc). The solid-phase immunoassay method, including the filtration blotting with SDS, would be applicable to determining even more sensitively proteins other than PrP(Sc), especially those having rigid conformations.
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Affiliation(s)
- Yoshiteru Kobayashi
- New Business and Technology Development Operations, Wako Pure Chemical Industries, Chuo-ku, Osaka 540-8605, Japan.
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32
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Narang HK, Dagdanova A, Xie Z, Yang Q, Chen SG. Sensitive detection of prion protein in human urine. Exp Biol Med (Maywood) 2005; 230:343-9. [PMID: 15855301 DOI: 10.1177/153537020523000508] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Transmissible spongiform encephalopathies are a group of infectious diseases typically associated with the accumulation of a protease-resistant and beta-sheet-rich prion protein, PrPSc, in affected brains. PrPSc is an altered isoform derived from the host-encoded glycoprotein, PrPC. The expression of PrPC is the highest in brain tissue, but it can also be detected at low levels in peripheral tissue. However, it is unclear whether a significant amount of PrPC is released into body fluid and excreted into urine. We have developed a simple, rapid method for the reliable detection of PrPC in urine from normal subjects by Western blotting. Our method can easily and reliably detect PrPC in apparently healthy individuals using less than 1 ml of urine in which the amount of urinary PrPC is estimated to be in the range of low micrograms/liter.
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Affiliation(s)
- Harash K Narang
- BioTech Global, 22-40 Brentwood Avenue, Newcastle Upon Tyne, UK
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33
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Arbel M, Lavie V, Solomon B. Generation of antibodies against prion protein in wild-type mice via helix 1 peptide immunization. J Neuroimmunol 2003; 144:38-45. [PMID: 14597096 DOI: 10.1016/j.jneuroim.2003.08.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We present here the development of antibodies against prion protein in BALB/C mice using as antigen human helix 1 of PrP. This sequence is suggested to be involved in protein pathological conformational changes, and is distinguished from that of mice by one amino acid. The immune tolerance to an 'almost-self' epitope and the poor immunogenicity of short peptides was overcome by using Multiple Antigen Peptide displaying eight copies of helix 1. The generated antibodies recognize the whole prion protein with a high binding constant and the established protocol may lead to an active immunization towards therapeutics of prion disease.
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Affiliation(s)
- Michal Arbel
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv, Tel-Aviv 69978, Israel
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34
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Ridley RM. What would T. H. Huxley have made of prion diseases? Mol Biotechnol 2003; 24:243-56. [PMID: 12777692 DOI: 10.1385/mb:24:3:243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
T. H. Huxley was "Darwin's bulldog," and took the offensive in championing the cause of evolution against skeptical scientists and outraged theologians. As such, he took part in one of the great "paradigm shifts" of biology, at the end of the nineteenth century. Huxley was a rigorous scientist and wrote important articles on scientific method, as well as publishing extensively on a wide range of subjects in natural history. In the second half of the twentieth century, the "prion hypothesis" was put forward to explain the pathogenesis of a curious group of diseases known as the transmissible spongiform encephalopathies. This also involved a "paradigm shift" because the prion hypothesis postulated that biologically relevant information could be enciphered in protein conformation (rather than encoded in nucleic acid base sequences), and could be transmitted from one molecule to another, thereby causing infectious disease. This article examines a few of Huxley's remarks to speculate on how he might have responded to the scientific debate about prion disease had he lived a century later.
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Affiliation(s)
- Rosalind M Ridley
- Innes Building, School of Clinical Veterinary Medicine, Madingley Road, Cambridge CB3 OEs, England.
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35
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DeArmond SJ, Prusiner SB. Perspectives on prion biology, prion disease pathogenesis, and pharmacologic approaches to treatment. Clin Lab Med 2003; 23:1-41. [PMID: 12733423 DOI: 10.1016/s0272-2712(02)00041-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The main goals of this article have been to summarize our current understanding of the biology of PrP, the propagation of prions, and the etiology and pathogenesis of each form of prion disease (familial, sporadic, and infectious); and to review current rational pharmacologic strategies for treatment of prion diseases. Each of these subjects is presented primarily from the perspective of investigations performed by the prion disease research laboratories at the University of California in San Francisco and by its many collaborators in the United States and abroad. This review focuses on key results from the hundreds of transgenic mouse lines expressing different PrP constructs that have been used to determine the roles played by different PrPSc and PrPC domains in prion propagation and the prion disease phenotype.
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Affiliation(s)
- Stephen J DeArmond
- Department of Pathology (Neuropathology Unit), Institute for Neurodegenerative Diseases, University of California, 513 Parnassus Avenue, San Francisco, CA, USA.
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36
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Peretz D, Williamson RA, Legname G, Matsunaga Y, Vergara J, Burton DR, DeArmond SJ, Prusiner SB, Scott MR. A change in the conformation of prions accompanies the emergence of a new prion strain. Neuron 2002; 34:921-32. [PMID: 12086640 DOI: 10.1016/s0896-6273(02)00726-2] [Citation(s) in RCA: 191] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To investigate the role of the pathogenic prion protein (PrP(Sc)) in controlling susceptibility to foreign prions, two Syrian hamster (SHa) prion strains, Sc237 and DY, were transmitted to transgenic mice expressing chimeric SHa/mouse PrP genes, Tg(MH2M). First passage of SHa(Sc237) prions exhibited prolonged incubation times, diagnostic of a species barrier. PrP(Sc) of the new MH2M(Sc237) strain possessed different structural properties from those of SHa(Sc237), as demonstrated by relative conformational stability measurements. This change was accompanied by a disease phenotype different from the SHa(Sc237) strain. Conversely, transmission of SHa(DY) prions to Tg(MH2M) mice showed no species barrier, and the MH2M(DY) strain retained the conformational and disease-specific properties of SHa(DY). These results suggest a causal relationship between species barriers, changes in PrP(Sc) conformation, and the emergence of new prion strains.
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Affiliation(s)
- David Peretz
- Institute for Neurodegenerative Diseases, Department of Neurology, University of California, San Francisco, CA 94143, USA
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37
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Narang H. A critical review of the nature of the spongiform encephalopathy agent: protein theory versus virus theory. Exp Biol Med (Maywood) 2002; 227:4-19. [PMID: 11788778 DOI: 10.1177/153537020222700103] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
All spongiform encephalopathies (SEs) result in brain disorders brought about by a slow virus. Since the origin of bovine SE (BSE), the infectious nature of the disease has been firmly established. Tubulofilamentous particles/scrapie termed nemavirus (NVP) and scrapie-associated fibrils (SAF) are ultrastructural markers, whereas protease-resistant protein (PrP(sc)) is a protein marker. The PrP molecules aggregate to form SAF. Each NVP consists of three layers: an outer protein coat, an intermediate ssDNA layer, and inner PrP/SAF. Therefore, ssDNA and PrP/SAF are physically associated with each other. The existence of at least 20 stable strains of SEs implies that a nucleic acid molecule serves as the information molecule. Animals inoculated with PrP(sc) do not develop the clinical disease, however, ssDNA purified from scrapie-hamster brains by alkaline gel electrophoresis mixed with binding proteins before inoculation developed the clinical disease. It appears that an "accessory protein" coded by the ssDNA of the NVP interacts with normal PrP(c) molecules, resulting in their conversion to PrP(sc)/SAF. The pathogenesis process in the infected animal, with increasing incubation periods, reveals that larger amounts of normal PrP molecules are modified to form SAF. This interferes with the normal supply of PrP to cell membranes, which become disrupted and eventually fragment, resulting in the vacuoles typical of those found in the SEs. Critical review of scientific literature has demonstrated that the agent contains a DNA genome.
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Affiliation(s)
- Harash Narang
- Ken Bell International, Newcastle Upon Tyne NE2 3DH, United Kingdom.
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38
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Moore RC, Mastrangelo P, Bouzamondo E, Heinrich C, Legname G, Prusiner SB, Hood L, Westaway D, DeArmond SJ, Tremblay P. Doppel-induced cerebellar degeneration in transgenic mice. Proc Natl Acad Sci U S A 2001; 98:15288-93. [PMID: 11734625 PMCID: PMC65022 DOI: 10.1073/pnas.251550798] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Doppel (Dpl) is a paralog of the mammalian prion protein (PrP); it is abundant in testes but expressed at low levels in the adult central nervous system. In two Prnp-deficient (Prnp(0/0)) mouse lines (Ngsk and Rcm0), Dpl overexpression correlated with ataxia and death of cerebellar neurons. To determine whether Dpl overexpression, rather than the dysregulation of genes neighboring the Prn gene complex, was responsible for the ataxic syndrome, we placed the mouse Dpl coding sequence under the control of the Prnp promoter and produced transgenic (Tg) mice on the Prnp(0/0)-ZrchI background (hereafter referred to as ZrchI). ZrchI mice exhibit neither Dpl overexpression nor cerebellar degeneration. In contrast, Tg(Dpl)ZrchI mice showed cerebellar granule and Purkinje cell loss; the age of onset of ataxia was inversely proportional to the levels of Dpl protein. Crosses of Tg mice overexpressing wild-type PrP with two lines of Tg(Dpl)ZrchI mice resulted in a phenotypic rescue of the ataxic syndrome, while Dpl overexpression was unchanged. Restoration of PrP expression also rendered the Tg(Dpl) mice susceptible to prion infection, with incubation times indistinguishable from non-Tg controls. Whereas the rescue of Dpl-induced neurotoxicity by coexpression of PrP argues for an interaction between the PrP and Dpl proteins in vivo, the unaltered incubation times in Tg mice overexpressing Dpl in the central nervous system suggest that Dpl is unlikely to be involved in prion formation.
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Affiliation(s)
- R C Moore
- Institute for Neurodegenerative Diseases, Department of Neurology, University of California, San Francisco, CA 94143, USA
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39
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Narang HK. Lingering doubts about spongiform encephalopathy and Creutzfeldt-Jakob disease. Exp Biol Med (Maywood) 2001; 226:640-52. [PMID: 11444100 DOI: 10.1177/153537020222600710] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Bovine spongiform encephalopathy (BSE) is an infectious disease and has been transmitted orally to many other animals, including humans. There is clear evidence of maternal transmission, although disagreement on the source of the BSE agent remains. The current theories link the origin of BSE to common scrapie in sheep. Twenty different strains of the scrapie agent have been isolated from sheep. A search of the literature indicates two distinct clinical syndromes in sheep, both of which have been called scrapie. I have designated these Type I (the common type), which exhibits itchiness and lose their wool, and Type II, which exhibits trembling and ataxia. Sheep inoculated with BSE develop Type II scrapie and they exhibit trembling. When cattle or mink are injected with the Type I strain, only a few will develop a clinical disease. By contrast, no clinical disease has so far been shown in cattle or mink by feeding them with Type I-infected sheep brains. However, either by injecting or feeding with the BSE strain, 100% of calves and mink develop the clinical disease. Evidence suggests that Type II is the cause of BSE. Identical clinical signs of Type II trembling are found in kuru and many of the recent cases of Creutzfeldt-Jakob disease. The BSE agent has caused spongiform encephalopathies (SEs) in domestic cats, tigers, and in some species of ruminants in zoos. The nature of the BSE agent remains unchanged when passaged through a range of species, irrespective of their genetic make up, demonstrating that variations in the host PrP gene are not a major factor in the susceptibility to the BSE agent. Since more than 85 zoo animals of many species have been diagnosed with SEs, from these studies it seems reasonable to conclude that the BSE agent can infect almost all mammalian species, including humans. For eradication of BSE and to reduce the risk of infection to humans, the development of a vaccine against BSE is suggested. Such a possibility should be fully explored.
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Affiliation(s)
- H K Narang
- Ken Bell International, 22-40 Brentwood Avenue, Newcastle Upon Tyne NE2 3DH, UK.
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40
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Affiliation(s)
- S B Prusiner
- Institute for Neurodegenerative Diseases and the Department of Neurology, University of California, San Francisco 94143-0518, USA
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41
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Dear DV, Fitzmaurice TJ, Garton S, Richards SJ. Pilot study to determine the feasibility of producing protease-resistant prion protein fragments by random PCR mutagenesis. Biochem Biophys Res Commun 2001; 281:929-35. [PMID: 11237750 DOI: 10.1006/bbrc.2001.4450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report the results of a pilot study to determine the feasibility of using PCR random mutagenesis and in vitro transcription/translation to produce protease resistant full-length or truncated ovine prion proteins (PrP). Using this approach, we show the novel production of protease resistant recombinant ovine prion protein fragments isolated from a panel of seventy randomly mutated ovine PrP protein molecules. Protease resistance of the proteinase K (PK) digested fragments was present de novo within physiological conditions without the need for template-assisted conversion to protease resistance or the requirement of reductants, denaturants or acid pH reported to date. Four of the mutant proteins were truncated at their C-termini and all of these gave rise to digestion products which were protease resistant at significant PK concentrations and exposure times. All other mutant proteins translated as full length molecules and gave rise to PK-resistant products which showed a variability in their proteinase digestion profiles. We discuss the relevance of these finding to current research.
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Affiliation(s)
- D V Dear
- Alzheimer's Disease and Prion Research Group, University of Cambridge School of Clinical Medicine, Department of Medicine, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 2QQ, United Kingdom
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42
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Appel TR, Wolff M, von Rheinbaben F, Heinzel M, Riesner D. Heat stability of prion rods and recombinant prion protein in water, lipid and lipid-water mixtures. J Gen Virol 2001; 82:465-473. [PMID: 11161287 DOI: 10.1099/0022-1317-82-2-465] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Prion rods, i.e. insoluble infectious aggregates of the N-terminally truncated form of the prion protein, PrP 27-30, and the corresponding recombinant protein, rPrP(90-231), were autoclaved in water, bovine lipid or lipid-water mixtures for 20 min at temperatures from 100 to 170 degrees C. A protocol was developed for the quantitative precipitation of small amounts of protein from large excesses of lipid. PrP remaining undegraded after autoclaving was quantified by Western blot and degradation factors were calculated. The Arrhenius plot of the rate of degradation vs temperature yielded linear relationships for prion rods in water or lipid-water as well as for rPrP(90-231) in lipid-water. The presence of lipids increased the heat stability of prion rods, especially at lower temperatures. Prion rods had a much higher thermal stability compared to rPrP. Autoclaving of prion rods in pure lipid gave different results - not simple degradation but bands indicative of covalently linked dimers, tetramers and higher aggregates. The heat stability of prion rods in pure lipid exceeded that in lipid-water mixtures. Degradation factors larger than 10(4) were reached at 170 degrees C in the presence of lipids and at 150 degrees C in the absence of lipids. The linear correlation of the data allows cautious extrapolation to conditions not tested, i.e. temperatures higher than 170 degrees C. A factual basis for assessing the biological safety of industrial processes utilizing potentially BSE-or scrapie-contaminated animal fat is provided.
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Affiliation(s)
- Thomas Raul Appel
- Heinrich-Heine-Universität Düsseldorf, Institut für Physikalische Biologie, Gebäude 26.12, D-40225 Düsseldorf, Germany1
| | - Michael Wolff
- Heinrich-Heine-Universität Düsseldorf, Institut für Physikalische Biologie, Gebäude 26.12, D-40225 Düsseldorf, Germany1
| | | | | | - Detlev Riesner
- Heinrich-Heine-Universität Düsseldorf, Institut für Physikalische Biologie, Gebäude 26.12, D-40225 Düsseldorf, Germany1
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43
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Porcher E, Gatto M. Quantifying the dynamics of prion infection: a bifurcation analysis of Laurent's model. J Theor Biol 2000; 205:283-96. [PMID: 10873439 DOI: 10.1006/jtbi.2000.2068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Laurent (1996a, Médecine/sciences12, 774-785; 1996b, Biochem. J.318, 35-39; 1998, Bio-phys. Chem.72, 211-222) proposed a model for the dynamics of diseases of the central nervous system caused by prions. It is based on the protein-only hypothesis (Prusiner et al., 1981, Proc. Natl. Acad. Sci. U.S.A.78, 6675-6679), which assumes that infection can be spread by particular proteins (prions) that can exist in two forms that share the same sequence, but have a different structure. The normal form is harmless, while the infectious isoform of the prion protein catalyses a transconformation from the native isoform to itself within a specialized compartment of the brain cells. This paper systematically explores the model behavior with the aim of quantifying the fundamental parameters characterizing the dynamics of prion infection. To this end we use data from the literature to fix orders of magnitude for the rates of synthesis and degradation of the native form of prion protein and for the shape of the autocatalytic function. The dynamical behavior is classified with respect to two unknown parameters (bifurcation analysis): the rate of spontaneous transconformation and the rate of output of the infectious isoform from the specialized compartment. We thus find that the bistability properties evidenced by Laurent are confined to a certain range of parameters and that permanent oscillations of the two isoforms concentrations are possible. The bifurcation analysis allows us to estimate approximate ranges for the values of the two unknown parameters and consequently to derive incubation times and compare them with actual data for hamster. Also, our study predicts that the output rate of the infectious isoform is relatively insensitive to variations of model parameters.
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Affiliation(s)
- E Porcher
- Laboratoire Ecologie, Systématique et Evolution, Université Paris-Sud, Bâtiment 362, Orsay Cedex, 91405, France
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44
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Haeberlé AM, Ribaut-Barassin C, Bombarde G, Mariani J, Hunsmann G, Grassi J, Bailly Y. Synaptic prion protein immuno-reactivity in the rodent cerebellum. Microsc Res Tech 2000; 50:66-75. [PMID: 10871550 DOI: 10.1002/1097-0029(20000701)50:1<66::aid-jemt10>3.0.co;2-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The cellular prion protein PrP(c) is a neurolemmal glycoprotein essential for the development of the transmissible spongiform encephalopathies. In these neurodegenerative diseases, host PrP(c) is converted to infectious protease-resistant isoforms PrP(res) or prions. Prions provoque predictable and distinctive patterns of PrP(res) accumulation and neurodegeneration depending on the prion strain and on regional cell-specific properties modulating PrP(c) affinity for infectious PrP(res) in the host brain. Synaptolysis and synaptic accumulation of PrP(res) during PrP-related diseases suggests that the synapses could be primary sites able to propagate PrP(res) and neurodegeneration in the central nervous system. In the rodent cerebellum, the present light and electron microscopic immuno-cytochemical analysis shows that distinct types of synapses display differential expression of PrP(c), suggesting that synapse-specific parameters could influence neuroinvasion and neurodegeneration following cerebral infection by prions. Although the physiological functions of PrP(c) remain unknown, the concentration of PrP(c) almost exclusively at the Purkinje cell synapses in the cerebellum suggests its critical involvement in the synaptic relationships between cerebellar neurons in agreement with their known vulnerability to PrP deficiencies.
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Affiliation(s)
- A M Haeberlé
- Laboratoire de Neurobiologie Cellulaire UPR 9009 CNRS 5, rue Blaise Pascal, 67084 Strasbourg, France
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45
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Affiliation(s)
- S J DeArmond
- Department of Pathology (Neuropathology), University of California, San Francisco 94143-0506, USA.
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46
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Kuczius T, Groschup MH. Differences in Proteinase K Resistance and Neuronal Deposition of Abnormal Prion Proteins Characterize Bovine Spongiform Encephalopathy (BSE) and Scrapie Strains. Mol Med 1999. [DOI: 10.1007/bf03402129] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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47
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Labat ML. Possible retroviral origin of prion disease: could prion disease be reconsidered as a preleukemia syndrome? Biomed Pharmacother 1999; 53:47-53. [PMID: 10221168 DOI: 10.1016/s0753-3322(99)80060-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
A retroviral etiology might explain why amyloid plaque and/or spongiosis are or are not associated with neuronal death in prion diseases. While retroviral genes themselves may be responsible for neuronal death, a retrovirus may also cause mutations in cellular genes. Hence, the prion gene may be altered by a retrovirus in the same way as a cellular proto-oncogene is altered to produce an oncogene, either by transduction or by integration of the provirus in its vicinity. In both cases, the resulting abnormal prion protein, acting as a catalyst, may induce the formation of amyloid plaques. In addition, a wild type retrovirus may recombine to the vesicular stomatitis virus (VSV) to give rise to a pseudotyped retrovirus able to induce spongiosis. It is reported here that in scrapie, a blood monocytoid cell proliferates in vitro. If confirmed in other species, this raises the question of the potential link between prion disease and leukemia. Indeed neurovirulent strains of murine leukemia virus, a slow acting retrovirus, are known to induce spongiform encephalopathies. A preliminary attempt to purify reverse transcriptase by chromatography, using the classical protocol, failed because of the presence of a prion-like protein secreted by the blood mononuclear cells which stuck to the phosphocellulose column. Therefore, if a retrovirus is present in prion diseases, it would be evidenced only in animals developing the disease in the absence of prion protein. From this point of view, mice obtained in 1997 by the group of D. Dormont in France, offer a unique opportunity to test the retroviral hypothesis.
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Affiliation(s)
- M L Labat
- Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
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Yokoyama T. The immunodetection of the abnormal isoform of prion protein. THE HISTOCHEMICAL JOURNAL 1999; 31:209-12. [PMID: 10447061 DOI: 10.1023/a:1003514021800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Transmissible spongiform encephalopathies such as scrapie in sheep and goats, Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy in cattle, are neurodegenerative disorders. A proposed causative agent for these diseases is an infectious protein, the so called 'prion'. An abnormal isoform of prion protein (PrPSc) can be detected according to the prion propagation method used. As PrPSc appears to constitute the main, if not the only, infectious entity its detection for the diagnosis of prion diseases is important. Immunodetection methods for PrPSc analysis are popular tools for diagnosis and research studies. In this paper, a review of the present knowledge concerning immunodetection is presented and the enhancement of the immunoreactivity of antisera to mouse and hamster prion protein peptides using the techniques of Western blotting and immunohistochemistry is summarized.
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Affiliation(s)
- T Yokoyama
- National Institute of Animal Health, Tsukuba, Ibaraki, Japan
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49
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Abstract
Prions are unprecedented infectious pathogens that cause a group of invariably fatal neurodegenerative diseases by an entirely novel mechanism. Prion diseases may present as genetic, infectious, or sporadic disorders, all of which involve modification of the prion protein (PrP). Bovine spongiform encephalopathy (BSE), scrapie of sheep, and Creutzfeldt-Jakob disease (CJD) of humans are among the most notable prion diseases. Prions are transmissible particles that are devoid of nucleic acid and seem to be composed exclusively of a modified protein (PrPSc). The normal, cellular PrP (PrPC) is converted into PrPSc through a posttranslational process during which it acquires a high beta-sheet content. The species of a particular prion is encoded by the sequence of the chromosomal PrP gene of the mammals in which it last replicated. In contrast to pathogens carrying a nucleic acid genome, prions appear to encipher strain-specific properties in the tertiary structure of PrPSc. Transgenetic studies argue that PrPSc acts as a template upon which PrPC is refolded into a nascent PrPSc molecule through a process facilitated by another protein. Miniprions generated in transgenic mice expressing PrP, in which nearly half of the residues were deleted, exhibit unique biological properties and should facilitate structural studies of PrPSc. While knowledge about prions has profound implications for studies of the structural plasticity of proteins, investigations of prion diseases suggest that new strategies for the prevention and treatment of these disorders may also find application in the more common degenerative diseases.
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Affiliation(s)
- S B Prusiner
- Departments of Neurology and of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
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Abstract
While many aspects of prion disease biology are unorthodox, perhaps the most fundamental paradox is posed by the coexistence of inherited, sporadic, and infectious forms of these diseases. Sensible molecular mechanisms for prion propagation must explain all three forms of prion diseases in a manner that is compatible with the formidable array of experimental data derived from histopathological, biochemical, biophysical, human genetic, and transgenetic studies. In this review, we explore prion disease pathogenesis initially from the perspective of an autosomal dominant inherited disease. Subsequently, we examine how an intrinsically inherited disease could present in sporadic and infectious forms. Finally, we explore the phenomenologic constraints on models of prion replication with a specific emphasis on biophysical studies of prion protein structures.
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Affiliation(s)
- F E Cohen
- Department of Biochemistry and Biophysics, University of California, San Francisco 94143, USA.
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