1
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Roseman GP, Wu B, Wadolkowski MA, Harris DA, Millhauser GL. Intrinsic toxicity of the cellular prion protein is regulated by its conserved central region. FASEB J 2020; 34:8734-8748. [PMID: 32385908 DOI: 10.1096/fj.201902749rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 04/08/2020] [Accepted: 04/20/2020] [Indexed: 11/11/2022]
Abstract
The conserved central region (CR) of PrPC has been hypothesized to serve as a passive linker connecting the protein's toxic N-terminal and globular C-terminal domains. Yet, deletion of the CR causes neonatal fatality in mice, implying the CR possesses a protective function. The CR encompasses the regulatory α-cleavage locus, and additionally facilitates a regulatory metal ion-promoted interaction between the PrPC N- and C-terminal domains. To elucidate the role of the CR and determine why CR deletion generates toxicity, we designed PrPC constructs wherein either the cis-interaction or α-cleavage are selectively prevented. These constructs were interrogated using nuclear magnetic resonance, electrophysiology, and cell viability assays. Our results demonstrate the CR is not a passive linker and the native sequence is crucial for its protective role over the toxic N-terminus, irrespective of α-cleavage or the cis-interaction. Additionally, we find that the CR facilitates homodimerization of PrPC , attenuating the toxicity of the N-terminus.
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Affiliation(s)
- Graham P Roseman
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Bei Wu
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Mark A Wadolkowski
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
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2
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Biggi S, Pancher M, Stincardini C, Luotti S, Massignan T, Dalle Vedove A, Astolfi A, Gatto P, Lolli G, Barreca ML, Bonetto V, Adami V, Biasini E. Identification of compounds inhibiting prion replication and toxicity by removing PrP C from the cell surface. J Neurochem 2019; 152:136-150. [PMID: 31264722 DOI: 10.1111/jnc.14805] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/19/2019] [Accepted: 06/23/2019] [Indexed: 12/11/2022]
Abstract
The vast majority of therapeutic approaches tested so far for prion diseases, transmissible neurodegenerative disorders of human and animals, tackled PrPSc , the aggregated and infectious isoform of the cellular prion protein (PrPC ), with largely unsuccessful results. Conversely, targeting PrPC expression, stability or cell surface localization are poorly explored strategies. We recently characterized the mode of action of chlorpromazine, an anti-psychotic drug known to inhibit prion replication and toxicity by inducing the re-localization of PrPC from the plasma membrane. Unfortunately, chlorpromazine possesses pharmacokinetic properties unsuitable for chronic use in vivo, namely low specificity and high toxicity. Here, we employed HEK293 cells stably expressing EGFP-PrP to carry out a semi-automated high content screening (HCS) of a chemical library directed at identifying non-cytotoxic molecules capable of specifically relocalizing PrPC from the plasma membrane as well as inhibiting prion replication in N2a cell cultures. We identified four candidate hits inducing a significant reduction in cell surface PrPC , one of which also inhibited prion propagation and toxicity in cell cultures in a strain-independent fashion. This study defines a new screening method and novel anti-prion compounds supporting the notion that removing PrPC from the cell surface could represent a viable therapeutic strategy for prion diseases.
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Affiliation(s)
- Silvia Biggi
- Dulbecco Telethon Laboratory of Prions and Amyloids, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Michael Pancher
- HTS Core Facility, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Claudia Stincardini
- Dulbecco Telethon Laboratory of Prions and Amyloids, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Silvia Luotti
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Tania Massignan
- HTS Core Facility, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Andrea Dalle Vedove
- Laboratory of Protein Crystallography and Structure-Based Drug Design, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Andrea Astolfi
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Pamela Gatto
- HTS Core Facility, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Graziano Lolli
- Laboratory of Protein Crystallography and Structure-Based Drug Design, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | | | - Valentina Bonetto
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Valentina Adami
- HTS Core Facility, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Emiliano Biasini
- Dulbecco Telethon Laboratory of Prions and Amyloids, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
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3
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Mercer RC, Harris DA. Identification of anti-prion drugs and targets using toxicity-based assays. Curr Opin Pharmacol 2019; 44:20-27. [PMID: 30684854 DOI: 10.1016/j.coph.2018.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/18/2018] [Accepted: 12/20/2018] [Indexed: 01/24/2023]
Abstract
Prion diseases are untreatable and invariably fatal, making the discovery of effective therapeutic interventions a priority. Most candidate molecules have been discovered based on their ability to reduce the levels of PrPSc, the infectious form of the prion protein, in cultured neuroblastoma cells. We have employed an alternative assay, based on an abnormal cellular phenotype associated with a mutant prion protein, to discover a novel class of anti-prion compounds, the phenethyl piperidines. Using an assay that monitors the acute toxic effects of PrPSc on the synapses of cultured hippocampal neurons, we have identified p38 MAPK as a druggable pharmacological target that is already being pursued for the treatment of other human diseases. Organotypic brain slices, which can propagate prions and mimic several neuropathological features of the disease, have also been used to test inhibitory compounds. An effective anti-prion regimen will involve synergistic combination of drugs acting at multiple steps of the pathogenic process, resulting not only in reduction in prion levels but also suppression of neurotoxic signaling.
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Affiliation(s)
- Robert Cc Mercer
- Boston University School of Medicine, Boston, MA 02118, United States
| | - David A Harris
- Boston University School of Medicine, Boston, MA 02118, United States.
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4
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Stincardini C, Massignan T, Biggi S, Elezgarai SR, Sangiovanni V, Vanni I, Pancher M, Adami V, Moreno J, Stravalaci M, Maietta G, Gobbi M, Negro A, Requena JR, Castilla J, Nonno R, Biasini E. An antipsychotic drug exerts anti-prion effects by altering the localization of the cellular prion protein. PLoS One 2017; 12:e0182589. [PMID: 28787011 PMCID: PMC5546605 DOI: 10.1371/journal.pone.0182589] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/20/2017] [Indexed: 02/01/2023] Open
Abstract
Prion diseases are neurodegenerative conditions characterized by the conformational conversion of the cellular prion protein (PrPC), an endogenous membrane glycoprotein of uncertain function, into PrPSc, a pathological isoform that replicates by imposing its abnormal folding onto PrPC molecules. A great deal of evidence supports the notion that PrPC plays at least two roles in prion diseases, by acting as a substrate for PrPSc replication, and as a mediator of its toxicity. This conclusion was recently supported by data suggesting that PrPC may transduce neurotoxic signals elicited by other disease-associated protein aggregates. Thus, PrPC may represent a convenient pharmacological target for prion diseases, and possibly other neurodegenerative conditions. Here, we sought to characterize the activity of chlorpromazine (CPZ), an antipsychotic previously shown to inhibit prion replication by directly binding to PrPC. By employing biochemical and biophysical techniques, we provide direct experimental evidence indicating that CPZ does not bind PrPC at biologically relevant concentrations. Instead, the compound exerts anti-prion effects by inducing the relocalization of PrPC from the plasma membrane. Consistent with these findings, CPZ also inhibits the cytotoxic effects delivered by a PrP mutant. Interestingly, we found that the different pharmacological effects of CPZ could be mimicked by two inhibitors of the GTPase activity of dynamins, a class of proteins involved in the scission of newly formed membrane vesicles, and recently reported as potential pharmacological targets of CPZ. Collectively, our results redefine the mechanism by which CPZ exerts anti-prion effects, and support a primary role for dynamins in the membrane recycling of PrPC, as well as in the propagation of infectious prions.
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Affiliation(s)
- Claudia Stincardini
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Tania Massignan
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Silvia Biggi
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Saioa R. Elezgarai
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Valeria Sangiovanni
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Ilaria Vanni
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, Rome, Italy
| | - Michael Pancher
- HTS Core Facility, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Valentina Adami
- HTS Core Facility, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Jorge Moreno
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio
| | - Matteo Stravalaci
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Giulia Maietta
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Marco Gobbi
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Alessandro Negro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Jesús R. Requena
- CIMUS Biomedical Research Institute, University of Santiago de Compostela, Santiago de Compostela, Spain
- Department of Medical Sciences, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Joaquín Castilla
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio
- IKERBASQUE, Basque Foundation for Science, Bilbao, Bizkaia, Spain
| | - Romolo Nonno
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, Rome, Italy
| | - Emiliano Biasini
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
- * E-mail:
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5
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Imberdis T, Heeres JT, Yueh H, Fang C, Zhen J, Rich CB, Glicksman M, Beeler AB, Harris DA. Identification of Anti-prion Compounds using a Novel Cellular Assay. J Biol Chem 2016; 291:26164-26176. [PMID: 27803163 DOI: 10.1074/jbc.m116.745612] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/19/2016] [Indexed: 11/06/2022] Open
Abstract
Prion diseases are devastating neurodegenerative disorders with no known cure. One strategy for developing therapies for these diseases is to identify compounds that block conversion of the cellular form of the prion protein (PrPC) into the infectious isoform (PrPSc). Most previous efforts to discover such molecules by high-throughput screening methods have utilized, as a read-out, a single kind of cellular assay system: neuroblastoma cells that are persistently infected with scrapie prions. Here, we describe the use of an alternative cellular assay based on suppressing the spontaneous cytotoxicity of a mutant form of PrP (Δ105-125). Using this assay, we screened 75,000 compounds, and identified a group of phenethyl piperidines (exemplified by LD7), which reduces the accumulation of PrPSc in infected neuroblastoma cells by >90% at low micromolar doses, and inhibits PrPSc-induced synaptotoxicity in hippocampal neurons. By analyzing the structure-activity relationships of 35 chemical derivatives, we defined the pharmacophore of LD7, and identified a more potent derivative. Active compounds do not alter total or cell-surface levels of PrPC, and do not bind to recombinant PrP in surface plasmon resonance experiments, although at high concentrations they inhibit PrPSc-seeded conversion of recombinant PrP to a misfolded state in an in vitro reaction (RT-QuIC). This class of small molecules may provide valuable therapeutic leads, as well as chemical biological tools to identify cellular pathways underlying PrPSc metabolism and PrPC function.
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Affiliation(s)
- Thibaut Imberdis
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - James T Heeres
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Han Yueh
- the Department of Chemistry, Boston University, Boston, Massachusetts 02115, and
| | - Cheng Fang
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Jessie Zhen
- the Department of Chemistry, Boston University, Boston, Massachusetts 02115, and
| | - Celeste B Rich
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Marcie Glicksman
- the Laboratory for Drug Discovery in Neurodegeneration, Brigham and Women's Hospital, Harvard Medical School, Cambridge, Massachusetts 02139
| | - Aaron B Beeler
- the Department of Chemistry, Boston University, Boston, Massachusetts 02115, and
| | - David A Harris
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118,
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6
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Massignan T, Cimini S, Stincardini C, Cerovic M, Vanni I, Elezgarai SR, Moreno J, Stravalaci M, Negro A, Sangiovanni V, Restelli E, Riccardi G, Gobbi M, Castilla J, Borsello T, Nonno R, Biasini E. A cationic tetrapyrrole inhibits toxic activities of the cellular prion protein. Sci Rep 2016; 6:23180. [PMID: 26976106 PMCID: PMC4791597 DOI: 10.1038/srep23180] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/29/2016] [Indexed: 12/11/2022] Open
Abstract
Prion diseases are rare neurodegenerative conditions associated with the conformational conversion of the cellular prion protein (PrPC) into PrPSc, a self-replicating isoform (prion) that accumulates in the central nervous system of affected individuals. The structure of PrPSc is poorly defined, and likely to be heterogeneous, as suggested by the existence of different prion strains. The latter represents a relevant problem for therapy in prion diseases, as some potent anti-prion compounds have shown strain-specificity. Designing therapeutics that target PrPC may provide an opportunity to overcome these problems. PrPC ligands may theoretically inhibit the replication of multiple prion strains, by acting on the common substrate of any prion replication reaction. Here, we characterized the properties of a cationic tetrapyrrole [Fe(III)-TMPyP], which was previously shown to bind PrPC, and inhibit the replication of a mouse prion strain. We report that the compound is active against multiple prion strains in vitro and in cells. Interestingly, we also find that Fe(III)-TMPyP inhibits several PrPC-related toxic activities, including the channel-forming ability of a PrP mutant, and the PrPC-dependent synaptotoxicity of amyloid-β (Aβ) oligomers, which are associated with Alzheimer’s Disease. These results demonstrate that molecules binding to PrPC may produce a dual effect of blocking prion replication and inhibiting PrPC-mediated toxicity.
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Affiliation(s)
- Tania Massignan
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy.,Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Sara Cimini
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Claudia Stincardini
- Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Milica Cerovic
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Ilaria Vanni
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, 00161 Rome, Italy
| | - Saioa R Elezgarai
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy.,Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Jorge Moreno
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio 48160, Bizkaia, Spain
| | - Matteo Stravalaci
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Alessandro Negro
- Department of Biomedical Sciences, University of Padova, 35121 Padova, Italy
| | - Valeria Sangiovanni
- Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Elena Restelli
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Geraldina Riccardi
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, 00161 Rome, Italy
| | - Marco Gobbi
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Joaquín Castilla
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio 48160, Bizkaia, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Bizkaia, Spain
| | - Tiziana Borsello
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy.,Department of Pharmacological and Biomolecular Sciences, Milan University, 20133 Milan Italy
| | - Romolo Nonno
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, 00161 Rome, Italy
| | - Emiliano Biasini
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy.,Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, 00161 Rome, Italy.,Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
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7
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Vilches S, Vergara C, Nicolás O, Mata Á, Del Río JA, Gavín R. Domain-Specific Activation of Death-Associated Intracellular Signalling Cascades by the Cellular Prion Protein in Neuroblastoma Cells. Mol Neurobiol 2015; 53:4438-48. [PMID: 26250617 DOI: 10.1007/s12035-015-9360-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/13/2015] [Indexed: 10/23/2022]
Abstract
The biological functions of the cellular prion protein remain poorly understood. In fact, numerous studies have aimed to determine specific functions for the different protein domains. Studies of cellular prion protein (PrP(C)) domains through in vivo expression of molecules carrying internal deletions in a mouse Prnp null background have provided helpful data on the implication of the protein in signalling cascades in affected neurons. Nevertheless, understanding of the mechanisms underlying the neurotoxicity induced by these PrP(C) deleted forms is far from complete. To better define the neurotoxic or neuroprotective potential of PrP(C) N-terminal domains, and to overcome the heterogeneity of results due to the lack of a standardized model, we used neuroblastoma cells to analyse the effects of overexpressing PrP(C) deleted forms. Results indicate that PrP(C) N-terminal deleted forms were properly processed through the secretory pathway. However, PrPΔF35 and PrPΔCD mutants led to death by different mechanisms sharing loss of alpha-cleavage and activation of caspase-3. Our data suggest that both gain-of-function and loss-of-function pathogenic mechanisms may be associated with N-terminal domains and may therefore contribute to neurotoxicity in prion disease. Dissecting the molecular response induced by PrPΔF35 may be the key to unravelling the physiological and pathological functions of the prion protein.
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Affiliation(s)
- Silvia Vilches
- Molecular and Cellular Neurobiotechnology, Barcelona Science Park, Institute for Bioengineering of Catalonia (IBEC), Parc Científic de Catalunya, Baldiri Reixac 15-21, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Cristina Vergara
- Molecular and Cellular Neurobiotechnology, Barcelona Science Park, Institute for Bioengineering of Catalonia (IBEC), Parc Científic de Catalunya, Baldiri Reixac 15-21, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Department of Cell Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Oriol Nicolás
- Molecular and Cellular Neurobiotechnology, Barcelona Science Park, Institute for Bioengineering of Catalonia (IBEC), Parc Científic de Catalunya, Baldiri Reixac 15-21, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Department of Cell Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Ágata Mata
- Molecular and Cellular Neurobiotechnology, Barcelona Science Park, Institute for Bioengineering of Catalonia (IBEC), Parc Científic de Catalunya, Baldiri Reixac 15-21, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Department of Cell Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - José A Del Río
- Molecular and Cellular Neurobiotechnology, Barcelona Science Park, Institute for Bioengineering of Catalonia (IBEC), Parc Científic de Catalunya, Baldiri Reixac 15-21, 08028, Barcelona, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. .,Department of Cell Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
| | - Rosalina Gavín
- Molecular and Cellular Neurobiotechnology, Barcelona Science Park, Institute for Bioengineering of Catalonia (IBEC), Parc Científic de Catalunya, Baldiri Reixac 15-21, 08028, Barcelona, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. .,Department of Cell Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
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8
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Solomon IH, Biasini E, Harris DA. Ion channels induced by the prion protein: mediators of neurotoxicity. Prion 2012; 6:40-5. [PMID: 22453177 DOI: 10.4161/pri.6.1.18627] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prion diseases comprise a group of rapidly progressive and invariably fatal neurodegenerative disorders for which there are no effective treatments. While conversion of the cellular prion protein (PrP(C)) to a β-sheet rich isoform (PrP(Sc) ) is known to be a critical event in propagation of infectious prions, the identity of the neurotoxic form of PrP and its mechanism of action remain unclear. Insights into this mechanism have been provided by studying PrP molecules harboring deletions and point mutations in the conserved central region, encompassing residues 105-125. When expressed in transgenic mice, PrP deleted for these residues (Δ105-125) causes a spontaneous neurodegenerative illness that is reversed by co-expression of wild-type PrP. In cultured cells, Δ105-125 PrP confers hypersensitivity to certain cationic antibiotics and induces spontaneous ion channel activity that can be recorded by electrophysiological techniques. We have utilized these drug-hypersensitization and current-inducing activities to identify which PrP domains and subcellular locations are required for toxicity. We present an ion channel model for the toxicity of Δ105-125 PrP and related mutants and speculate how a similar mechanism could mediate PrP(Sc)-associated toxicity. Therapeutic regimens designed to inhibit prion-induced toxicity, as well as formation of PrP(Sc) , may prove to be the most clinically beneficial.
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Affiliation(s)
- Isaac H Solomon
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
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9
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Biasini E, Turnbaugh JA, Massignan T, Veglianese P, Forloni G, Bonetto V, Chiesa R, Harris DA. The toxicity of a mutant prion protein is cell-autonomous, and can be suppressed by wild-type prion protein on adjacent cells. PLoS One 2012; 7:e33472. [PMID: 22428057 PMCID: PMC3299791 DOI: 10.1371/journal.pone.0033472] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 02/09/2012] [Indexed: 12/25/2022] Open
Abstract
Insight into the normal function of PrPC, and how it can be subverted to produce neurotoxic effects, is provided by PrP molecules carrying deletions encompassing the conserved central region. The most neurotoxic of these mutants, Δ105–125 (called ΔCR), produces a spontaneous neurodegenerative illness when expressed in transgenic mice, and this phenotype can be dose-dependently suppressed by co-expression of wild-type PrP. Whether the toxic activity of ΔCR PrP and the protective activity or wild-type PrP are cell-autonomous, or can be exerted on neighboring cells, is unknown. To investigate this question, we have utilized co-cultures of differentiated neural stem cells derived from mice expressing ΔCR or wild-type PrP. Cells from the two kinds of mice, which are marked by the presence or absence of GFP, are differentiated together to yield neurons, astrocytes, and oligodendrocytes. As a surrogate read-out of ΔCR PrP toxicity, we assayed sensitivity of the cells to the cationic antibiotic, Zeocin. In a previous study, we reported that cells expressing ΔCR PrP are hypersensitive to the toxic effects of several cationic antibiotics, an effect that is suppressed by co-expression of wild type PrP, similar to the rescue of the neurodegenerative phenotype observed in transgenic mice. Using this system, we find that while ΔCR-dependent toxicity is cell-autonomous, the rescuing activity of wild-type PrP can be exerted in trans from nearby cells. These results provide important insights into how ΔCR PrP subverts a normal physiological function of PrPC, and the cellular mechanisms underlying the rescuing process.
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Affiliation(s)
- Emiliano Biasini
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Dulbecco Telethon Institute, Milan, Italy
- Department of Neuroscience, Mario Negri Institute, Milan, Italy
- * E-mail: (EB); (DAH)
| | - Jessie A. Turnbaugh
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Tania Massignan
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Dulbecco Telethon Institute, Milan, Italy
- Department of Biochemistry and Molecular Pharmacology, Mario Negri Institute, Milan, Italy
| | | | | | - Valentina Bonetto
- Dulbecco Telethon Institute, Milan, Italy
- Department of Biochemistry and Molecular Pharmacology, Mario Negri Institute, Milan, Italy
| | - Roberto Chiesa
- Dulbecco Telethon Institute, Milan, Italy
- Department of Neuroscience, Mario Negri Institute, Milan, Italy
| | - David A. Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail: (EB); (DAH)
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Prion protein at the crossroads of physiology and disease. Trends Neurosci 2011; 35:92-103. [PMID: 22137337 DOI: 10.1016/j.tins.2011.10.002] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 10/20/2011] [Accepted: 10/20/2011] [Indexed: 11/23/2022]
Abstract
The presence of the cellular prion protein (PrP(C)) on the cell surface is critical for the neurotoxicity of prions. Although several biological activities have been attributed to PrP(C), a definitive demonstration of its physiological function remains elusive. In this review, we discuss some of the proposed functions of PrP(C), focusing on recently suggested roles in cell adhesion, regulation of ionic currents at the cell membrane and neuroprotection. We also discuss recent evidence supporting the idea that PrP(C) may function as a receptor for soluble oligomers of the amyloid β peptide and possibly other toxic protein aggregates. These data suggest surprising new connections between the physiological function of PrP(C) and its role in neurodegenerative diseases beyond those caused by prions.
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Solomon IH, Khatri N, Biasini E, Massignan T, Huettner JE, Harris DA. An N-terminal polybasic domain and cell surface localization are required for mutant prion protein toxicity. J Biol Chem 2011; 286:14724-36. [PMID: 21385869 DOI: 10.1074/jbc.m110.214973] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
There is evidence that alterations in the normal physiological activity of PrP(C) contribute to prion-induced neurotoxicity. This mechanism has been difficult to investigate, however, because the normal function of PrP(C) has remained obscure, and there are no assays available to measure it. We recently reported that cells expressing PrP deleted for residues 105-125 exhibit spontaneous ionic currents and hypersensitivity to certain classes of cationic drugs. Here, we utilize cell culture assays based on these two phenomena to test how changes in PrP sequence and/or cellular localization affect the functional activity of the protein. We report that the toxic activity of Δ105-125 PrP requires localization to the plasma membrane and depends on the presence of a polybasic amino acid segment at the N terminus of PrP. Several different deletions spanning the central region as well as three disease-associated point mutations also confer toxic activity on PrP. The sequence domains identified in our study are also critical for PrP(Sc) formation, suggesting that common structural features may govern both the functional activity of PrP(C) and its conversion to PrP(Sc).
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Affiliation(s)
- Isaac H Solomon
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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