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Sempou E, Biasini E, Pinzón-Olejua A, Harris DA, Málaga-Trillo E. Activation of zebrafish Src family kinases by the prion protein is an amyloid-β-sensitive signal that prevents the endocytosis and degradation of E-cadherin/β-catenin complexes in vivo. Mol Neurodegener 2016; 11:18. [PMID: 26860872 PMCID: PMC4748561 DOI: 10.1186/s13024-016-0076-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 01/18/2016] [Indexed: 11/25/2022] Open
Abstract
Background Prions and amyloid-β (Aβ) oligomers trigger neurodegeneration by hijacking a poorly understood cellular signal mediated by the prion protein (PrP) at the plasma membrane. In early zebrafish embryos, PrP-1-dependent signals control cell-cell adhesion via a tyrosine phosphorylation-dependent mechanism. Results Here we report that the Src family kinases (SFKs) Fyn and Yes act downstream of PrP-1 to prevent the endocytosis and degradation of E-cadherin/β-catenin adhesion complexes in vivo. Accordingly, knockdown of PrP-1 or Fyn/Yes cause similar zebrafish gastrulation phenotypes, whereas Fyn/Yes expression rescues the PrP-1 knockdown phenotype. We also show that zebrafish and mouse PrPs positively regulate the activity of Src kinases and that these have an unexpected positive effect on E-cadherin-mediated cell adhesion. Interestingly, while PrP knockdown impairs β-catenin adhesive function, PrP overexpression enhances it, thereby antagonizing its nuclear, wnt-related signaling activity and disturbing embryonic dorsoventral specification. The ability of mouse PrP to influence these events in zebrafish embryos requires its neuroprotective, polybasic N-terminus but not its neurotoxicity-associated central region. Remarkably, human Aβ oligomers up-regulate the PrP-1/SFK/E-cadherin/β-catenin pathway in zebrafish embryonic cells, mimicking a PrP gain-of-function scenario. Conclusions Our gain- and loss-of-function experiments in zebrafish suggest that PrP and SFKs enhance the cell surface stability of embryonic adherens junctions via the same complex mechanism through which they over-activate neuroreceptors that trigger synaptic damage. The profound impact of this pathway on early zebrafish development makes these embryos an ideal model to study the cellular and molecular events affected by neurotoxic PrP mutations and ligands in vivo. In particular, our finding that human Aβ oligomers activate the zebrafish PrP/SFK/E-cadherin pathway opens the possibility of using fish embryos to rapidly screen for novel therapeutic targets and compounds against prion- and Alzheimer's-related neurodegeneration. Altogether, our data illustrate PrP-dependent signals relevant to embryonic development, neuronal physiology and neurological disease. Electronic supplementary material The online version of this article (doi:10.1186/s13024-016-0076-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Emily Sempou
- Department of Biology, University of Konstanz, Constance, 78457, Germany. .,Present address: Department of Pediatrics, Yale University School of Medicine, New Haven, CT, 06520, USA.
| | - Emiliano Biasini
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA. .,Present address: Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123, Trento, Italy.
| | - Alejandro Pinzón-Olejua
- Department of Biology, University of Konstanz, Constance, 78457, Germany. .,Present address: Max PIanck Institute for Brain Research, Department of Synaptic Plasticity, 60438, Frankfurt/Main, Germany.
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA.
| | - Edward Málaga-Trillo
- Department of Biology, University of Konstanz, Constance, 78457, Germany. .,Department of Biology, Universidad Peruana Cayetano Heredia, Lima 31, Perú.
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Zhu S, Victoria GS, Marzo L, Ghosh R, Zurzolo C. Prion aggregates transfer through tunneling nanotubes in endocytic vesicles. Prion 2015; 9:125-35. [PMID: 25996400 PMCID: PMC4601206 DOI: 10.1080/19336896.2015.1025189] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 02/07/2015] [Accepted: 02/26/2015] [Indexed: 01/31/2023] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) are a group of neurodegenerative diseases caused by the misfolding of the cellular prion protein to an infectious form PrP(Sc). The intercellular transfer of PrP(Sc) is a question of immediate interest as the cell-to-cell movement of the infectious particle causes the inexorable propagation of disease. We have previously identified tunneling nanotubes (TNTs) as one mechanism by which PrP(Sc) can move between cells. Here we investigate further the details of this mechanism and show that PrP(Sc) travels within TNTs in endolysosomal vesicles. Additionally we show that prion infection of CAD cells increases both the number of TNTs and intercellular transfer of membranous vesicles, thereby possibly playing an active role in its own intercellular transfer via TNTs.
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Key Words
- Ab, antibody
- CFP, cyan fluorescent protein
- ER, endoplasmic reticulum
- ERC, endocytic recycling compartment
- GFP, green fluorescent protein
- PM, plasma membrane
- PrPC, cellular prion protein
- PrPSc, scrapie prion protein
- RFP, red fluorescent protein
- TNTs, tunneling nanotubes
- TSEs, transmissible spongiform encephalopathies
- endosomes
- neuronal cells
- prion
- transfer
- tunneling nanotubes
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Affiliation(s)
- Seng Zhu
- Unité Trafic Membranaire et Pathogenese, Institut Pasteur, Paris CEDEX 15, France
| | | | - Ludovica Marzo
- Unité Trafic Membranaire et Pathogenese, Institut Pasteur, Paris CEDEX 15, France
| | - Rupam Ghosh
- Unité Trafic Membranaire et Pathogenese, Institut Pasteur, Paris CEDEX 15, France
| | - Chiara Zurzolo
- Unité Trafic Membranaire et Pathogenese, Institut Pasteur, Paris CEDEX 15, France
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Ochs K, Málaga-Trillo E. Common themes in PrP signaling: the Src remains the same. Front Cell Dev Biol 2014; 2:63. [PMID: 25364767 PMCID: PMC4211543 DOI: 10.3389/fcell.2014.00063] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 10/02/2014] [Indexed: 01/06/2023] Open
Abstract
The ability of the cellular prion protein (PrPC) to trigger intracellular signals appears central to neurodegeneration pathways, yet the physiological significance of such signals is rather puzzling. For instance, PrPC deregulation disrupts phenomena as diverse as synaptic transmission in mammals and cell adhesion in zebrafish. Although unrelated, the key proteins in these events -the NMDA receptor (NMDAR) and E-cadherin, respectively- are similarly modulated by the Src family kinase (SFK) Fyn. These observations highlight the importance of PrPC-mediated Fyn activation, a finding reported nearly two decades ago. Given their complex functions and regulation, SFKs may hold the key to intriguing aspects of PrP biology such as its seemingly promiscuous functions and the lack of strong phenotypes in knockout mice. Here we provide a mechanistic perspective on how SFKs might contribute to the uncertain molecular basis of neuronal PrP phenotypes affecting ion channel activity, axon myelination and olfactory function. In particular, we discuss SFK target proteins involved in these processes and the role of tyrosine phosphorylation in the regulation of their activity and cell surface expression.
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Affiliation(s)
- Katharina Ochs
- Department of Biology, University of Konstanz Konstanz, Germany
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Söderberg KL, Guterstam P, Langel U, Gräslund A. Targeting prion propagation using peptide constructs with signal sequence motifs. Arch Biochem Biophys 2014; 564:254-61. [PMID: 25447819 DOI: 10.1016/j.abb.2014.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 12/25/2022]
Abstract
Synthetic peptides with sequences derived from the cellular prion protein (PrP(C)) unprocessed N-terminus are able to counteract the propagation of proteinase K resistant prions (PrP(Res), indicating the presence of the prion isoform of the prion protein) in cell cultures (Löfgren et al., 2008). The anti-prion peptides have characteristics like cell penetrating peptides (CPPs) and consist of the prion protein hydrophobic signal sequence followed by a polycationic motif (residues KKRPKP), in mouse PrP(C) corresponding to residues 1-28. Here we analyze the sequence elements required for the anti-prion effect of KKRPKP-conjugates. Neuronal GT1-1 cells were infected with either prion strain RML or 22L. Variable peptide constructs originating from the mPrP1-28 sequence were analyzed for anti-prion effects, measured as disappearance of proteinase K resistant prions (PrP(Res)) in the infected cell cultures. We find that even a 5 amino acid N-terminal shortening of the signal peptide abolishes the anti-prion effect. We show that the signal peptide from PrP(C) can be replaced with the signal peptide from the Neural cell adhesion molecule-1; NCAM11-19, with a retained capacity to reduce PrP(Res) levels. The anti-prion effect is lost if the polycationic N-terminal PrP(C)-motif is conjugated to any conventional CPP, such as TAT48-60, transportan-10 or penetratin. We propose a mechanism by which a signal peptide from a secretory or cell surface protein acts to promote the transport of a prion-binding polycationic PrP(C)-motif to a subcellular location where prion conversion occurs (most likely the Endosome Recycling Compartment), thereby targeting prion propagation.
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Affiliation(s)
- Kajsa Löfgren Söderberg
- The Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Peter Guterstam
- The Department of Neurochemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ulo Langel
- The Department of Neurochemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Astrid Gräslund
- The Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
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Didonna A. Prion protein and its role in signal transduction. Cell Mol Biol Lett 2013; 18:209-30. [PMID: 23479001 PMCID: PMC6275729 DOI: 10.2478/s11658-013-0085-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 02/18/2013] [Indexed: 11/20/2022] Open
Abstract
Prion diseases are a class of fatal neurodegenerative disorders that can be sporadic, genetic or iatrogenic. They are characterized by the unique nature of their etiologic agent: prions (PrP(Sc)). A prion is an infectious protein with the ability to convert the host-encoded cellular prion protein (PrP(C)) into new prion molecules by acting as a template. Since Stanley B. Prusiner proposed the "protein-only" hypothesis for the first time, considerable effort has been put into defining the role played by PrP(C) in neurons. However, its physiological function remains unclear. This review summarizes the major findings that support the involvement of PrP(C) in signal transduction.
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Affiliation(s)
- Alessandro Didonna
- Davee Department of Neurology, Feinberg School of Medicine Northwestern University, Chicago, IL 60611, USA.
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Wessler S, Backert S. Abl family of tyrosine kinases and microbial pathogenesis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 286:271-300. [PMID: 21199784 DOI: 10.1016/b978-0-12-385859-7.00006-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Abl nonreceptor tyrosine kinases are activated by multiple stimuli and regulate cytoskeletal reorganization, cell proliferation, survival, and stress responses. Several downstream pathways have direct impact on physiological processes, including development and maintenance of the nervous and immune systems and epithelial morphogenesis. Recent studies also indicated that numerous viral and bacterial pathogens highjack Abl signaling for different purposes. Abl kinases are activated to reorganize the host actin cytoskeleton and promote the direct tyrosine phosphorylation of viral surface proteins and injected bacterial type-III and type-IV effector molecules. However, Abl kinases also play other roles in infectious processes of bacteria, viruses, and prions. These activities have crucial impact on microbial invasion and release from host cells, actin-based motility, pedestal formation, as well as cell-cell dissociation involved in epithelial barrier disruption and other responses. Thus, Abl kinases exhibit important functions in pathological signaling during microbial infections. Here, we discuss the different signaling pathways activated by pathogens and highlight possible therapeutic intervention strategies.
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Affiliation(s)
- Silja Wessler
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billrothstrasse, Salzburg, Austria
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Wagner W, Ajuh P, Löwer J, Wessler S. Quantitative phosphoproteomic analysis of prion-infected neuronal cells. Cell Commun Signal 2010; 8:28. [PMID: 20920157 PMCID: PMC2955621 DOI: 10.1186/1478-811x-8-28] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 09/28/2010] [Indexed: 11/10/2022] Open
Abstract
Prion diseases or transmissible spongiform encephalopathies (TSEs) are fatal diseases associated with the conversion of the cellular prion protein (PrPC) to the abnormal prion protein (PrPSc). Since the molecular mechanisms in pathogenesis are widely unclear, we analyzed the global phospho-proteome and detected a differential pattern of tyrosine- and threonine phosphorylated proteins in PrPSc-replicating and pentosan polysulfate (PPS)-rescued N2a cells in two-dimensional gel electrophoresis. To quantify phosphorylated proteins, we performed a SILAC (stable isotope labeling by amino acids in cell culture) analysis and identified 105 proteins, which showed a regulated phosphorylation upon PrPSc infection. Among those proteins, we validated the dephosphorylation of stathmin and Cdc2 and the induced phosphorylation of cofilin in PrPSc-infected N2a cells in Western blot analyses. Our analysis showed for the first time a differentially regulated phospho-proteome in PrPSc infection, which could contribute to the establishment of novel protein markers and to the development of novel therapeutic intervention strategies in targeting prion-associated disease.
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Affiliation(s)
- Wibke Wagner
- Paul Ehrlich Institute, Paul Ehrlich-Straße 51-59, D-63225 Langen, Germany.
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Yu C, Nwabuisi-Heath E, Laxton K, Ladu MJ. Endocytic pathways mediating oligomeric Abeta42 neurotoxicity. Mol Neurodegener 2010; 5:19. [PMID: 20478062 PMCID: PMC2881055 DOI: 10.1186/1750-1326-5-19] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 05/17/2010] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND One pathological hallmark of Alzheimer's disease (AD) is amyloid plaques, composed primarily of amyloid-beta peptide (Abeta). Over-production or diminished clearance of the 42 amino acid form of Abeta (Abeta42) in the brain leads to accumulation of soluble Abeta and plaque formation. Soluble oligomeric Abeta (oAbeta) has recently emerged to be as a likely proximal cause of AD. RESULTS Here we demonstrate that endocytosis is critical in mediating oAbeta42-induced neurotoxicity and intraneuronal accumulation of Abeta. Inhibition of clathrin function either with a pharmacological inhibitor, knock-down of clathrin heavy chain expression, or expression of the dominant-negative mutant of clathrin-assembly protein AP180 did not block oAbeta42-induced neurotoxicity or intraneuronal accumulation of Abeta. However, inhibition of dynamin and RhoA by expression of dominant negative mutants reduced neurotoxicity and intraneuronal Abeta accumulation. Pharmacologic inhibition of the dynamin-mediated endocytic pathway by genistein also reduced neurotoxicity. CONCLUSIONS These data suggest that dynamin-mediated and RhoA-regulated endocytosis are integral steps for oligomeric Abeta42-induced neurotoxicity and intraneuronal Abeta accumulation.
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Affiliation(s)
- Chunjiang Yu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA.
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Löfgren K, Cheng F, Fransson LÅ, Bedecs K, Mani K. Involvement of glypican-1 autoprocessing in scrapie infection. Eur J Neurosci 2008; 28:964-72. [DOI: 10.1111/j.1460-9568.2008.06386.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Löfgren K, Wahlström A, Lundberg P, Langel Ö, Gräslund A, Bedecs K. Antiprion properties of prion protein‐derived cell‐penetrating peptides. FASEB J 2008; 22:2177-84. [DOI: 10.1096/fj.07-099549] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Kajsa Löfgren
- Department of Biochemistry and Biophysics The Arrhenius Laboratories Department of Neurochemistry and NeurotoxicologyStockholm UniversityStockholmSweden
| | - Anna Wahlström
- Department of Biochemistry and Biophysics The Arrhenius Laboratories Department of Neurochemistry and NeurotoxicologyStockholm UniversityStockholmSweden
| | - Pontus Lundberg
- Department of Neurochemistry and NeurotoxicologyStockholm UniversityStockholmSweden
| | - Ölo Langel
- Department of Neurochemistry and NeurotoxicologyStockholm UniversityStockholmSweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics The Arrhenius Laboratories Department of Neurochemistry and NeurotoxicologyStockholm UniversityStockholmSweden
| | - Katarina Bedecs
- Department of Biochemistry and Biophysics The Arrhenius Laboratories Department of Neurochemistry and NeurotoxicologyStockholm UniversityStockholmSweden
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Bate C, Tayebi M, Williams A. Sequestration of free cholesterol in cell membranes by prions correlates with cytoplasmic phospholipase A2 activation. BMC Biol 2008; 6:8. [PMID: 18269734 PMCID: PMC2270799 DOI: 10.1186/1741-7007-6-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Accepted: 02/12/2008] [Indexed: 12/03/2022] Open
Abstract
Background The transmissible spongiform encephalopathies (TSEs), otherwise known as the prion diseases, occur following the conversion of the normal cellular prion protein (PrPC) to an alternatively folded isoform (PrPSc). The accumulation of PrPSc within the brain leads to neurodegeneration through an unidentified mechanism. Since many neurodegenerative disorders including prion, Parkinson's and Alzheimer's diseases may be modified by cholesterol synthesis inhibitors, the effects of prion infection on the cholesterol balance within neuronal cells were examined. Results We report the novel observation that prion infection altered the membrane composition and significantly increased total cholesterol levels in two neuronal cell lines (ScGT1 and ScN2a cells). There was a significant correlation between the concentration of free cholesterol in ScGT1 cells and the amounts of PrPSc. This increase was entirely a result of increased amounts of free cholesterol, as prion infection reduced the amounts of cholesterol esters in cells. These effects were reproduced in primary cortical neurons by the addition of partially purified PrPSc, but not by PrPC. Crucially, the effects of prion infection were not a result of increased cholesterol synthesis. Stimulating cholesterol synthesis via the addition of mevalonate, or adding exogenous cholesterol, had the opposite effect to prion infection on the cholesterol balance. It did not affect the amounts of free cholesterol within neurons; rather, it significantly increased the amounts of cholesterol esters. Immunoprecipitation studies have shown that cytoplasmic phospholipase A2 (cPLA2) co-precipitated with PrPSc in ScGT1 cells. Furthermore, prion infection greatly increased both the phosphorylation of cPLA2 and prostaglandin E2 production. Conclusion Prion infection, or the addition of PrPSc, increased the free cholesterol content of cells, a process that could not be replicated by the stimulation of cholesterol synthesis. The presence of PrPSc increased solubilisation of free cholesterol in cell membranes and affected their function. It increased activation of the PLA2 pathway, previously implicated in PrPSc formation and in PrPSc-mediated neurotoxicity. These observations suggest that the neuropathogenesis of prion diseases results from PrPSc altering cholesterol-sensitive processes. Furthermore, they raise the possibility that disturbances in membrane cholesterol are major triggering events in neurodegenerative diseases.
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Affiliation(s)
- Clive Bate
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Herts, AL9 7TA, UK.
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Bedecs K. Cell culture models to unravel prion protein function and aberrancies in prion diseases. Methods Mol Biol 2008; 459:1-20. [PMID: 18576144 DOI: 10.1007/978-1-59745-234-2_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
From an early stage of prion research, tissue cultures that could support and propagate the scrapie agent were sought after. The earliest attempts were explants from brains of infected mice, and their growth and morphological characteristics were compared with those from uninfected mice. Using the explant technique, several investigators reported increased cell growth in cultures established from scrapie-sick brain compared with cultures from normal mice. These are odd findings in the light of the massive neuronal cell death known to occur in scrapie-infected brains; however, the cell types responsible for the increased cell growth in the scrapie-explants most probably were not neuronal. The first successful cell culture established in this way, in which the scrapie agent was serially and continuously passaged beyond the initial explant, was in the scrapie mouse brain culture, which is still used today. This chapter describes the generation and use of chronically prion-infected cell lines as cell culture models of prion diseases. These cell lines have been crucial for the current understanding of the cell biology of both the normal (PrP(C)) and the pathogenic isoform (PrP(Sc)) of the prion protein. They also have been useful in the development of antiprion drugs, prospectively used for therapy of prion diseases, and they offer an alternative approach for transmission/infectivity assays normally performed by mouse bioassay. Cell culture models also have been used to study prion-induced cytopathological changes, which could explain the typical spongiform neurodegeneration in prion diseases.
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Affiliation(s)
- Katarina Bedecs
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
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