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Guichard C, Ivanyi-Nagy R, Sharma KK, Gabus C, Marc D, Mély Y, Darlix JL. Analysis of nucleic acid chaperoning by the prion protein and its inhibition by oligonucleotides. Nucleic Acids Res 2011; 39:8544-58. [PMID: 21737432 PMCID: PMC3201874 DOI: 10.1093/nar/gkr554] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Prion diseases are unique neurodegenerative illnesses associated with the conversion of the cellular prion protein (PrP(C)) into the aggregated misfolded scrapie isoform, named PrP(Sc). Recent studies on the physiological role of PrP(C) revealed that this protein has probably multiple functions, notably in cell-cell adhesion and signal transduction, and in assisting nucleic acid folding. In fact, in vitro findings indicated that the human PrP (huPrP) possesses nucleic acid binding and annealing activities, similarly to nucleic acid chaperone proteins that play essential roles in cellular DNA and RNA metabolism. Here, we show that a peptide, representing the N-terminal domain of huPrP, facilitates nucleic acid annealing by two parallel pathways nucleated through the stem termini. We also show that PrP of human or ovine origin facilitates DNA strand exchange, ribozyme-directed cleavage of an RNA template and RNA trans-splicing in a manner similar to the nucleocapsid protein of HIV-1. In an attempt to characterize inhibitors of PrP-chaperoning in vitro we discovered that the thioaptamer 5'-GACACAAGCCGA-3' was extensively inhibiting the PrP chaperoning activities. At the same time a recently characterized methylated oligoribonucleotide inhibiting the chaperoning activity of the HIV-1 nucleocapsid protein was poorly impairing the PrP chaperoning activities.
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Affiliation(s)
- Cécile Guichard
- Unité de Virologie Humaine INSERM, ENS, IFR 128, 46 allée d'Italie, 69364 Lyon, France
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Bongarzone S, Tran HNA, Cavalli A, Roberti M, Rosini M, Carloni P, Legname G, Bolognesi ML. Hybrid Lipoic Acid Derivatives to Attack Prion Disease on Multiple Fronts. ChemMedChem 2011; 6:601-5. [DOI: 10.1002/cmdc.201100072] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Indexed: 11/12/2022]
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53
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Synthesis of GN8 derivatives and evaluation of their antiprion activity in TSE-infected cells. Bioorg Med Chem Lett 2011; 21:1502-7. [DOI: 10.1016/j.bmcl.2010.12.132] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 12/27/2010] [Accepted: 12/29/2010] [Indexed: 11/17/2022]
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Delmouly K, Belondrade M, Casanova D, Milhavet O, Lehmann S. HEPES inhibits the conversion of prion protein in cell culture. J Gen Virol 2011; 92:1244-1250. [PMID: 21289158 DOI: 10.1099/vir.0.027334-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
HEPES is a well-known buffering reagent used in cell-culture medium. Interestingly, this compound is also responsible for significant modifications of biological parameters such as uptake of organic molecules, alteration of oxidative stress mechanisms or inhibition of ion channels. While using cell-culture medium supplemented with HEPES on prion-infected cells, it was noticed that there was a significant concentration-dependent inhibition of accumulation of the abnormal isoform of the prion protein (PrP(Sc)). This effect was present only in live cells and was thought to be related to modification of the PrP environment or biology. These results could modify the interpretation of cell-culture assays of prion therapeutic agents, as well as of previous cell biology results obtained in the field using HEPES buffers. This inhibitory effect of HEPES could also be exploited to prevent contamination or propagation of prions in cell culture.
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Affiliation(s)
- Karine Delmouly
- Institut de Génétique Humaine, CNRS-UPR 1142, 141 rue de la Cardonille, 34396 Montpellier Cedex 5, France
| | - Maxime Belondrade
- Institut de Génétique Humaine, CNRS-UPR 1142, 141 rue de la Cardonille, 34396 Montpellier Cedex 5, France
| | - Danielle Casanova
- Institut de Génétique Humaine, CNRS-UPR 1142, 141 rue de la Cardonille, 34396 Montpellier Cedex 5, France
| | - Ollivier Milhavet
- Institut de Génétique Humaine, CNRS-UPR 1142, 141 rue de la Cardonille, 34396 Montpellier Cedex 5, France
| | - Sylvain Lehmann
- Institut de Recherches en Biothérapie (IRB), Biochimie - Protéomique Clinique, CHU de Montpellier, Université Montpellier 1, 34000 Montpellier, France.,Institut de Génétique Humaine, CNRS-UPR 1142, 141 rue de la Cardonille, 34396 Montpellier Cedex 5, France
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Bongarzone S, Tran HNA, Cavalli A, Roberti M, Carloni P, Legname G, Bolognesi ML. Parallel Synthesis, Evaluation, and Preliminary Structure−Activity Relationship of 2,5-Diamino-1,4-benzoquinones as a Novel Class of Bivalent Anti-Prion Compound. J Med Chem 2010; 53:8197-201. [DOI: 10.1021/jm100882t] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Salvatore Bongarzone
- Statistical and Biological Physics Sector, Neurobiology Sector, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy
- Italian Institute of Technology, SISSA-ISAS Unit, 34151 Trieste, Italy
| | | | - Andrea Cavalli
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
- Department of Drug Discovery and Development, Italian Institute of Technology, 16163 Genova, Italy
| | - Marinella Roberti
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
| | - Paolo Carloni
- Statistical and Biological Physics Sector, Neurobiology Sector, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy
- Italian Institute of Technology, SISSA-ISAS Unit, 34151 Trieste, Italy
- CNR-INFM-DEMOCRITOS Modeling Center for Research in Atomistic Simulation, 34151 Trieste, Italy
| | - Giuseppe Legname
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
| | - Maria Laura Bolognesi
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
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Abstract
The prion protein is well known because of its association with prion diseases. These diseases, which include variant CJD, are unusual because they are neurodegenerative diseases that can be transferred between individuals experimentally. The prion protein is also widely known as a copper binding protein. The binding of copper to the prion protein is possibly necessary for its normal cellular function. The prion protein has also been suggested to bind other metals, and among these, manganese. Despite over ten years of research on manganese and prion disease, this interaction has often been dismissed or at best seen as a poor cousin to the involvement of copper. However, recent data has shown that manganese could stabilise prions in the environment and that chelation therapy specifically aimed at manganese can extend the life of animals with prion disease. This article reviews the evidence for a link between prions and manganese.
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Affiliation(s)
- David R Brown
- Department of Biology and Biochemistry, University of Bath, Bath, UKBA2 7AY.
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Gawinecka J, Dieks J, Asif AR, Carimalo J, Heinemann U, Streich JH, Dihazi H, Schulz-Schaeffer W, Zerr I. Codon 129 polymorphism specific cerebrospinal fluid proteome pattern in sporadic Creutzfeldt-Jakob disease and the implication of glycolytic enzymes in prion-induced pathology. J Proteome Res 2010; 9:5646-57. [PMID: 20866111 DOI: 10.1021/pr1004604] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cerebrospinal fluid (CSF) contains a dynamic and complex mixture of proteins, which can reflect a physiological and pathological state of the central nervous system. In our present study, we show CSF protein patterns from patients with the two most frequent subtypes of sporadic Creutzfeldt-Jakob disease (sCJD) defined by the codon 129 genotype (MM, MV, and VV) and the protease-resistant form of prion protein (type 1 and type 2). The densitometric analysis of 2D gels showed up-regulation of 27 and down-regulation of 3 proteins in the MM-sCJD as well as the up-regulation of 24 proteins in the VV-sCJD as compared to nondemented control. Almost 40% of sCJD specific regulated proteins in CSF are involved in glucose metabolism, regardless of the codon 129 polymorphism. The increase in CSF levels of lactate dehydrogenase (LDH), glucose-6-phosphate isomerase (G6PI), and fructose-bisphosphate aldolase A (ALDOA) were validated on a larger group of sCJD patients including three possible codon 129 polymorphism carriers and three control groups consisting of nondemented, neurological cases as well as patients suffering from Alzheimer's disease or vascular dementia. Subsequently, the abundance of these glycolytic enzymes in the brain as well as their cellular localization were determined. This study demonstrates for the first time the implication of G6PI in prion-induced pathology as well as its cellular translocalization in sCJD. The identification of sCJD-regulated proteins in CSF of living symptomatic patients in our study can broaden our knowledge about pathological processes occurring in sCJD, as they are still not fully understood.
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Affiliation(s)
- Joanna Gawinecka
- Department of Clinical Chemistry, Medical Center Georg-August University, Goettingen, Germany
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58
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Real-time monitoring of copper ions-induced cytotoxicity by EIS cell chips. Biosens Bioelectron 2010; 25:2711-6. [DOI: 10.1016/j.bios.2010.04.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 04/02/2010] [Accepted: 04/21/2010] [Indexed: 11/22/2022]
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Singh N, Singh A, Das D, Mohan ML. Redox control of prion and disease pathogenesis. Antioxid Redox Signal 2010; 12:1271-94. [PMID: 19803746 PMCID: PMC2864664 DOI: 10.1089/ars.2009.2628] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 09/22/2009] [Accepted: 10/03/2009] [Indexed: 11/12/2022]
Abstract
Imbalance of brain metal homeostasis and associated oxidative stress by redox-active metals like iron and copper is an important trigger of neurotoxicity in several neurodegenerative conditions, including prion disorders. Whereas some reports attribute this to end-stage disease, others provide evidence for specific mechanisms leading to brain metal dyshomeostasis during disease progression. In prion disorders, imbalance of brain-iron homeostasis is observed before end-stage disease and worsens with disease progression, implicating iron-induced oxidative stress in disease pathogenesis. This is an unexpected observation, because the underlying cause of brain pathology in all prion disorders is PrP-scrapie (PrP(Sc)), a beta-sheet-rich conformation of a normal glycoprotein, the prion protein (PrP(C)). Whether brain-iron dyshomeostasis occurs because of gain of toxic function by PrP(Sc) or loss of normal function of PrP(C) remains unclear. In this review, we summarize available evidence suggesting the involvement of oxidative stress in prion-disease pathogenesis. Subsequently, we review the biology of PrP(C) to highlight its possible role in maintaining brain metal homeostasis during health and the contribution of PrP(Sc) in inducing brain metal imbalance with disease progression. Finally, we discuss possible therapeutic avenues directed at restoring brain metal homeostasis and alleviating metal-induced oxidative stress in prion disorders.
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Affiliation(s)
- Neena Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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60
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61
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Increased proportions of C1 truncated prion protein protect against cellular M1000 prion infection. J Neuropathol Exp Neurol 2009; 68:1125-35. [PMID: 19918124 DOI: 10.1097/nen.0b013e3181b96981] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Prion disease pathogenesis is linked to the cell-associated propagation of misfolded protease-resistant conformers (PrP) of the normal cellular prion protein (PrP). Ongoing PrP expression is the only known absolute requirement for successful prion disease transmission and PrP propagation. Further typifying prion disease is selective neuronal dysfunction and loss, although the precise mechanisms underlying this are undefined. We utilized a single prion strain (M1000) and a range of neuronal and nonneuronal, PrP endogenously expressing and transgenically modified overexpressing cell lines, to evaluate whether PrP glycosylation patterns or constitutive N-terminal cleavage events may be determinants of sustained PrP propagation. Our data demonstrates that relative proportions of full-length and C1 truncated PrP are the most important characteristics influencing susceptibility to sustained M1000 prion infection, supporting PrP alpha-cleavage as a protective event, which may contribute to the selective neuronal vulnerability observed in vivo.
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62
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Wolschner C, Giese A, Kretzschmar HA, Huber R, Moroder L, Budisa N. Design of anti- and pro-aggregation variants to assess the effects of methionine oxidation in human prion protein. Proc Natl Acad Sci U S A 2009; 106:7756-61. [PMID: 19416900 PMCID: PMC2674404 DOI: 10.1073/pnas.0902688106] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Indexed: 01/09/2023] Open
Abstract
Prion disease is characterized by the alpha-->beta structural conversion of the cellular prion protein (PrP(C)) into the misfolded and aggregated "scrapie" (PrP(Sc)) isoform. It has been speculated that methionine (Met) oxidation in PrP(C) may have a special role in this process, but has not been detailed and assigned individually to the 9 Met residues of full-length, recombinant human PrP(C) [rhPrP(C)(23-231)]. To better understand this oxidative event in PrP aggregation, the extent of periodate-induced Met oxidation was monitored by electrospray ionization-MS and correlated with aggregation propensity. Also, the Met residues were replaced with isosteric and chemically stable, nonoxidizable analogs, i.e., with the more hydrophobic norleucine (Nle) and the highly hydrophilic methoxinine (Mox). The Nle-rhPrP(C) variant is an alpha-helix rich protein (like Met-rhPrP(C)) resistant to oxidation that lacks the in vitro aggregation properties of the parent protein. Conversely, the Mox-rhPrP(C) variant is a beta-sheet rich protein that features strong proaggregation behavior. In contrast to the parent Met-rhPrP(C), the Nle/Mox-containing variants are not sensitive to periodate-induced in vitro aggregation. The experimental results fully support a direct correlation of the alpha-->beta secondary structure conversion in rhPrP(C) with the conformational preferences of Met/Nle/Mox residues. Accordingly, sporadic prion and other neurodegenerative diseases, as well as various aging processes, might also be caused by oxidative stress leading to Met oxidation.
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Affiliation(s)
- Christina Wolschner
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Armin Giese
- Zentrum für Neuropathologie und Prionforschung, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 23, 81377 Munich, Germany
| | - Hans A. Kretzschmar
- Zentrum für Neuropathologie und Prionforschung, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 23, 81377 Munich, Germany
| | - Robert Huber
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, D-82152 Martinsried, Germany
- School of Biosciences, Cardiff University, Cardiff CF10 3US, United Kingdom; and
- Zentrum für Medizinische Biotechnologie, Universität Duisburg-Essen, D-45117 Essen, Germany
| | - Luis Moroder
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Nediljko Budisa
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, D-82152 Martinsried, Germany
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Rachidi W, Chimienti F, Aouffen M, Senator A, Guiraud P, Seve M, Favier A. Prion protein protects against zinc-mediated cytotoxicity by modifying intracellular exchangeable zinc and inducing metallothionein expression. J Trace Elem Med Biol 2009; 23:214-23. [PMID: 19486831 DOI: 10.1016/j.jtemb.2009.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 02/11/2009] [Accepted: 02/12/2009] [Indexed: 11/30/2022]
Abstract
PrPC contains several octapeptide repeats sequences toward the N-terminus which have binding affinity for divalent metals such as copper, zinc, nickel and manganese. However, the link between PrPC expression and zinc metabolism remains elusive. Here we studied the relationship between PrPC and zinc ions intracellular homeostasis using a cell line expressing a doxycycline-inducible PrPC gene. No significant difference in 65Zn2+ uptake was observed in cells expressing PrPC when compared with control cells. However, PrPC-expressing cells were more resistant to zinc-induced toxicity, suggesting an adaptative mechanism induced by PrPC. Using zinquin-ethyl-ester, a specific fluorophore for vesicular free zinc, we observed a significant re-localization of intracellular exchangeable zinc in vesicles after PrPC expression. Finally, we demonstrated that PrPC expression induces metallothionein (MT) expression, a zinc-upregulated zinc-binding protein. Taken together, these results suggest that PrPC modifies the intracellular localization of zinc rather than the cellular content and induces MT upregulation. These findings are of major importance since zinc deregulation is implicated in several neurodegenerative disorders. It is postulated that in prion diseases the conversion of PrPC to PrPSc may deregulate zinc homeostasis mediated by metallothionein.
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Affiliation(s)
- Walid Rachidi
- INAC/SCIB/LAN, CEA de Grenoble, 17 rue des Martyrs, 38054 Grenoble, France.
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Variety of antiprion compounds discovered through an in silico screen based on cellular-form prion protein structure: Correlation between antiprion activity and binding affinity. Antimicrob Agents Chemother 2008; 53:765-71. [PMID: 19015328 DOI: 10.1128/aac.01112-08] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transmissible spongiform encephalopathies are associated with the conformational conversion of the prion protein from the cellular form (PrP(C)) to the scrapie form. This process could be disrupted by stabilizing the PrP(C) conformation, using a specific ligand identified as a chemical chaperone. To discover such compounds, we employed an in silico screen that was based on the nuclear magnetic resonance structure of PrP(C). In combination, we performed ex vivo screening using the Fukuoka-1 strain-infected neuronal mouse cell line at a compound concentration of 10 microM and surface plasmon resonance. Initially, we selected 590 compounds according to the calculated docked energy and finally discovered 24 efficient antiprion compounds, whose chemical structures are quite diverse. Surface plasmon resonance studies showed that the binding affinities of compounds for PrP(C) roughly correlated with the compounds' antiprion activities, indicating that the identification of chemical chaperones that bind to the PrP(C) structure and stabilize it is one efficient strategy for antiprion drug discovery. However, some compounds possessed antiprion activities with low affinities for PrP(C), indicating a mechanism involving additional modulation factors. We classified the compounds roughly into five categories: (i) binding and effective, (ii) low binding and effective, (iii) binding and not effective, (iv) low binding and not effective, and (v) acceleration. In conclusion, we found a spectrum of compounds, many of which are able to modulate the pathogenic conversion reaction. The appropriate categorization of these diverse compounds would facilitate antiprion drug discovery and help to elucidate the pathogenic conversion mechanism.
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65
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Antioxidants reduce endoplasmic reticulum stress and improve protein secretion. Proc Natl Acad Sci U S A 2008; 105:18525-30. [PMID: 19011102 DOI: 10.1073/pnas.0809677105] [Citation(s) in RCA: 539] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Protein misfolding in the endoplasmic reticulum (ER) contributes to the pathogenesis of many diseases. Although oxidative stress can disrupt protein folding, how protein misfolding and oxidative stress impact each other has not been explored. We have analyzed expression of coagulation factor VIII (FVIII), the protein deficient in hemophilia A, to elucidate the relationship between protein misfolding and oxidative stress. Newly synthesized FVIII misfolds in the ER lumen, activates the unfolded protein response (UPR), causes oxidative stress, and induces apoptosis in vitro and in vivo in mice. Strikingly, antioxidant treatment reduces UPR activation, oxidative stress, and apoptosis, and increases FVIII secretion in vitro and in vivo. The findings indicate that reactive oxygen species are a signal generated by misfolded protein in the ER that cause UPR activation and cell death. Genetic or chemical intervention to reduce reactive oxygen species improves protein folding and cell survival and may provide an avenue to treat and/or prevent diseases of protein misfolding.
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66
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The effect of Fenton reaction on protease-resistant prion protein (PrPSc) degradation and scrapie infectivity. Brain Res 2008; 1238:172-80. [DOI: 10.1016/j.brainres.2008.07.117] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 07/30/2008] [Accepted: 07/30/2008] [Indexed: 11/17/2022]
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67
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Soler L, Caffrey P, McMahon HE. Effects of new amphotericin analogues on the scrapie isoform of the prion protein. Biochim Biophys Acta Gen Subj 2008; 1780:1162-7. [DOI: 10.1016/j.bbagen.2008.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 06/19/2008] [Accepted: 07/11/2008] [Indexed: 12/01/2022]
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68
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Chasseigneaux S, Pastore M, Britton-Davidian J, Manié E, Stern MH, Callebert J, Catalan J, Casanova D, Belondrade M, Provansal M, Zhang Y, Bürkle A, Laplanche JL, Sévenet N, Lehmann S. Genetic heterogeneity versus molecular analysis of prion susceptibility in neuroblasma N2a sublines. Arch Virol 2008; 153:1693-702. [PMID: 18696008 DOI: 10.1007/s00705-008-0177-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 07/23/2008] [Indexed: 11/30/2022]
Abstract
The neuroblastoma-derived cell line N2a is permissive to certain prion strains but resistant sublines unable to accumulate the pathological proteinase-K resistant form of the prion protein can be isolated. We compared for gene expression and phenotypes different N2a sublines that were susceptible or resistant to the 22L prion strain. Karyotypes and comparative genomic hybridization arrays revealed chromosomal imbalances but did not demonstrate a characteristic profile of genomic alterations linked to prion susceptibility. Likewise, we showed that this phenotype was not dependent on the binding of PrPres, the expression of the prion protein gene, or on its primary sequence. We completed this analysis by looking using real-time quantitative PCR at the expression of a set of genes encoding proteins linked to prion biology. None of the candidates could account by itself for the infection phenotype, nevertheless sublines had distinct transcriptional profiles. Taken together, our results do not support a role for specific genomic abnormalities and possible candidate proteins in N2a prion susceptibility. They also reveal genetic heterogeneity among the sublines and serve as a guidance for further investigation into the molecular mechanisms of prion infection.
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Affiliation(s)
- Stéphanie Chasseigneaux
- EA 3621, Faculté de Pharmacie, Université Paris 5, 4 avenue de l'Observatoire, 75270 Paris cedex 06, France
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69
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Mouillet-Richard S, Nishida N, Pradines E, Laude H, Schneider B, Féraudet C, Grassi J, Launay JM, Lehmann S, Kellermann O. Prions impair bioaminergic functions through serotonin- or catecholamine-derived neurotoxins in neuronal cells. J Biol Chem 2008; 283:23782-90. [PMID: 18617522 DOI: 10.1074/jbc.m802433200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conversion of the cellular prion protein, PrP(C), to an abnormal isoform, PrP(Sc), is a central event leading to neurodegeneration in prion diseases. Deciphering the molecular and cellular changes imparted by PrP(Sc) accumulation remains an arduous task due to the small number of cell lines supporting prion replication. Here we introduce the 1C11 cell line as a new in vitro model to investigate prion pathogenesis. This cell line is a committed neuroectodermal progenitor able to differentiate into fully functional serotonergic or catecholaminergic neurons. 1C11 cells, which naturally express PrP(C) from the undifferentiated state, can be chronically infected with various prion strains. Prion infection does not promote any noticeable phenotypic change in the progenitor cells nor prevent the onset of the serotonergic and catecholaminergic differentiation programs. Pathogenic prions, however, deviate the overall neurotransmitter-metabolism in both pathways by decreasing bioamine synthesis, storage, and transport, and enhancing catabolism. Noteworthy, oxidized derivatives of both serotonin and catecholamines are selectively detected in the differentiated progenies of infected cells and contribute to irreversible impairment in bioamine synthesis. Finally, the level of PrP(Sc) accumulation, that of infectivity, and the extent of all prion-induced changes in infected cells appear to be correlated. The report of such specific effects of infection on neuronal functions provides a foundation for dissecting the events underlying loss of neuronal homeostasis in prion diseases.
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Affiliation(s)
- Sophie Mouillet-Richard
- Différenciation Cellulaire et prions, CNRS FRE 2937, Institut Pasteur, INSERM U747, 7 rue Guy Môquet, Villejuif, France.
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70
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Béranger F, Crozet C, Goldsborough A, Lehmann S. Trehalose impairs aggregation of PrPSc molecules and protects prion-infected cells against oxidative damage. Biochem Biophys Res Commun 2008; 374:44-8. [PMID: 18602368 DOI: 10.1016/j.bbrc.2008.06.094] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Accepted: 06/21/2008] [Indexed: 01/09/2023]
Abstract
Neurodegenerative disorders such as Alzheimer's, Huntington's, and prion diseases are characterized by abnormal protein deposits in the brain of affected patients. In prion diseases, a key event in the pathogenesis is the conversion of the normal prion protein (PrP(c)) into abnormal protease resistant PrP(Sc) deposits, a phenomenon associated with a higher sensitivity to oxidative stress in vitro. In cellular models of Alzheimer and Huntington diseases, the disaccharide trehalose has been shown to be effective in inhibiting huntingtin and Abeta peptide aggregates and reducing their associated toxicity. We show in this study that trehalose treatment of prion-infected cells decreases the size of de novo produced PrP(Sc) aggregates and modify their subcellular localization. Despite the fact that trehalose does not modify the protease resistance properties of PrP(Sc) molecules, it significantly protects prion-infected cells from induced oxidative damage, suggesting that this compound is of therapeutic interest.
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Affiliation(s)
- Florence Béranger
- Institut de Génétique Humaine, UPR CNRS1142, 141 Rue de Cardonille, 34396 Montpellier Cedex 5, France.
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Linden R, Martins VR, Prado MAM, Cammarota M, Izquierdo I, Brentani RR. Physiology of the prion protein. Physiol Rev 2008; 88:673-728. [PMID: 18391177 DOI: 10.1152/physrev.00007.2007] [Citation(s) in RCA: 435] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Prion diseases are transmissible spongiform encephalopathies (TSEs), attributed to conformational conversion of the cellular prion protein (PrP(C)) into an abnormal conformer that accumulates in the brain. Understanding the pathogenesis of TSEs requires the identification of functional properties of PrP(C). Here we examine the physiological functions of PrP(C) at the systemic, cellular, and molecular level. Current data show that both the expression and the engagement of PrP(C) with a variety of ligands modulate the following: 1) functions of the nervous and immune systems, including memory and inflammatory reactions; 2) cell proliferation, differentiation, and sensitivity to programmed cell death both in the nervous and immune systems, as well as in various cell lines; 3) the activity of numerous signal transduction pathways, including cAMP/protein kinase A, mitogen-activated protein kinase, phosphatidylinositol 3-kinase/Akt pathways, as well as soluble non-receptor tyrosine kinases; and 4) trafficking of PrP(C) both laterally among distinct plasma membrane domains, and along endocytic pathways, on top of continuous, rapid recycling. A unified view of these functional properties indicates that the prion protein is a dynamic cell surface platform for the assembly of signaling modules, based on which selective interactions with many ligands and transmembrane signaling pathways translate into wide-range consequences upon both physiology and behavior.
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Affiliation(s)
- Rafael Linden
- Instituto de Biofísica da Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Gudmundsdóttir KB, Kristinsson J, Sigurdarson S, Eiríksson T, Jóhannesson T. Glutathione peroxidase (GPX) activity in blood of ewes on farms in different scrapie categories in Iceland. Acta Vet Scand 2008; 50:23. [PMID: 18573202 PMCID: PMC2443150 DOI: 10.1186/1751-0147-50-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Accepted: 06/23/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Preliminary studies indicated decreased glutathione peroxidase (GPX) activity in blood of ewes on scrapie-afflicted farms. Other studies have shown decreased GPX activity in brain of prion-infected mice and in prion-infected cells in vitro. The aim of this study was to examine the GPX activity in blood as well as the distribution of GPX-activity levels from ewes on farms in scrapie-afflicted areas in Iceland. METHODS Blood samples were collected from 635 ewes (non-pregnant [n = 297] and pregnant [n = 338]) on 40 farms in scrapie-afflicted areas during the years 2001-2005, for analysis of GPX activity. The farms were divided into three categories: 1. Scrapie-free farms (n = 14); 2. Scrapie-prone farms (earlier scrapie-afflicted, restocked farms) (n = 12); 3. Scrapie-afflicted farms (n = 14). For comparison, 121 blood samples were also collected from non-pregnant ewes on one farm (farm A) in a scrapie-free area (scrapie never registered). Chi-square test was used to test for normal distribution of GPX-results, and Kruskal-Wallis test to compare GPX-results between categories. RESULTS The GPX-results appeared to be biphasically distributed in ewes in all three scrapie categories and on farm A. The presumptive breaking point was about 300 units g Hb-1. About 30-50% of the GPX-results from ewes in all three scrapie categories were below 300 units g Hb-1 but only about 13% of the GPX-results from ewes on farm A. The mean GPX activity was highest on farm A, and was significantly lower on scrapie-prone farms than on scrapie-free or scrapie-afflicted farms (non-pregnant and pregnant ewes: P < 0.005, respectively; non-pregnant and pregnant ewes combined: P < 0.0005). CONCLUSIONS 1) the distribution of GPX-results in blood of Icelandic ewes apparently has a biphasic character; 2) the GPX-results were higher in ewes on one farm in a scrapie-free area than in ewes on farms in the scrapie-afflicted areas; 3) GPX-activity levels were significantly lowest on earlier scrapie-afflicted, restocked farms, which might have a bearing on the recurrence of sporadic scrapie on these farms; 4) further study on the possible role of GPX activity in the occurrence of scrapie in Iceland is warranted.
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Mouse-adapted sporadic human Creutzfeldt-Jakob disease prions propagate in cell culture. Int J Biochem Cell Biol 2008; 40:2793-801. [PMID: 18590830 DOI: 10.1016/j.biocel.2008.05.024] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 05/27/2008] [Accepted: 05/29/2008] [Indexed: 10/22/2022]
Abstract
Cell based models used for the study of prion diseases have traditionally employed mouse-adapted strains of sheep scrapie prions. To date, attempts to generate human prion propagation in cell culture have been unsuccessful. Rabbit kidney epithelial cells (RK13) are permissive to infection with prions from a variety of species upon expression of cognate PrP transgenes. We explored RK13 cells expressing human PrP for their utility as a cell line capable of sustaining infection with human prions. RK13 cells processed exogenously expressed human PrP similarly to exogenously expressed mouse PrP but were not permissive to infection when exposed to sporadic Creutzfeldt-Jakob disease prions. Transmission of the same sporadic Creutzfeldt Jakob disease prions to wild-type mice generated a strain of mouse-adapted human prions, which efficiently propagated in RK13 cells expressing mouse PrP, demonstrating these cells are permissive to infection by mouse-adapted human prions. Our observations underscore the likelihood that, in contrast to prions derived from non-human mammals, additional unidentified cofactors or subcellular environment are critical for the generation of human prions.
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74
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Crozet C, Beranger F, Lehmann S. Cellular pathogenesis in prion diseases. Vet Res 2008; 39:44. [DOI: 10.1051/vetres:2008021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Accepted: 04/15/2008] [Indexed: 01/15/2023] Open
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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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77
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Vilette D. Cell models of prion infection. Vet Res 2007; 39:10. [PMID: 18073097 DOI: 10.1051/vetres:2007049] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Accepted: 09/24/2007] [Indexed: 11/14/2022] Open
Abstract
Due to recent renewal of interest and concerns in prion diseases, a number of cell systems permissive to prion multiplication have been generated in the last years. These include established cell lines, neuronal stem cells and primary neuronal cultures. While most of these models are permissive to experimental, mouse-adapted strains of prions, the propagation of natural field isolates from sheep scrapie and chronic wasting disease has been recently achieved. These models have improved our knowledge on the molecular and cellular events controlling the conversion of the PrP(C) protein into abnormal isoforms and on the cell-to-cell spreading of prions. Infected cultured cells will also facilitate investigations on the molecular basis of strain identity and on the mechanisms that lead to neurodegeneration. The ongoing development of new cell models with improved characteristics will certainly be useful for a number of unanswered critical issues in the prion field.
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Affiliation(s)
- Didier Vilette
- Unité Mixte de Recherche 1225, INRA, ENVT, 31000 Toulouse, France.
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78
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Julius C, Hutter G, Wagner U, Seeger H, Kana V, Kranich J, Klöhn PC, Klöhn P, Weissmann C, Miele G, Aguzzi A. Transcriptional stability of cultured cells upon prion infection. J Mol Biol 2007; 375:1222-33. [PMID: 18082765 DOI: 10.1016/j.jmb.2007.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 10/30/2007] [Accepted: 11/01/2007] [Indexed: 02/06/2023]
Abstract
Prion infections induce severe disruption of the central nervous system with neuronal vacuolation and extensive glial reactions, and invariably lead to death of affected individuals. The molecular underpinnings of these events are not well understood. To better define the molecular consequences of prion infections, we analyzed the transcriptional response to persistent prion infection in a panel of three murine neural cell lines in vitro. Colony spot immunochemistry assays indicated that 65-100% of cells were infected in each line. Only the Nav1 gene was marginally modulated in one cell line, whereas transcripts previously reported to be derailed in prion-infected cells were not confirmed in the present study. We attribute these discrepancies to the experimental stringency of the current study, which was performed under conditions designed to minimize potential genetic drifts. These findings are at striking variance with gene expression studies performed on whole brains upon prion infections in vivo, suggesting that many of the latter changes represent secondary reactions to infection. We conclude that, surprisingly, there are no universal transcriptional changes induced by prion infection of neural cells in vitro.
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Affiliation(s)
- Christian Julius
- Institute of Neuropathology, University Hospital of Zürich, Schmelzbergstrasse 12, CH-8091 Zürich, Switzerland
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79
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Lee VE, Schulman JM, Stiefel EI, Lee CC. Reversible precipitation of bovine serum albumin by metal ions and synthesis, structure and reactivity of new tetrathiometallate chelating agents. J Inorg Biochem 2007; 101:1707-18. [PMID: 17804073 DOI: 10.1016/j.jinorgbio.2007.07.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 07/11/2007] [Accepted: 07/12/2007] [Indexed: 12/01/2022]
Abstract
Independent research is an important component of any undergraduate chemistry program. This article reports the findings of two of many undergraduate research projects directed by Ed Stiefel in the hopes that the results will be inspiring and useful to the scientific community. The neurological disorders associated with insufficient copper in Menkes disease and an excess of copper in Wilson's disease are well established; however, recent evidence suggests that copper may also be involved in other disorders, such as Alzheimer's, angiogenesis, and prion diseases. The exact role of copper, however, is uncertain. This study examines the role of copper and zinc in the formation of protein deposits and the chelation and removal of the metal ions to reverse the process. The bovine serum albumin (BSA) protein forms a precipitate after the addition of approximately 6 copper(II) atoms or 8 zinc(II) atoms. Other metal ions, such as Ca(II), Al(III), Ni(II), and Co(II), did not precipitate the BSA even when the metal ion to BSA ratios were in excess of 1000. The copper and zinc protein precipitates returned to solution after addition of the chelating agents, ethylenediaminetetraacetic acid (EDTA) or tetrathiometallates [(MS(4)(2-)), where M=Mo, W]. Two new choline and acetylcholine tetrathiomolybdate and tetrathiotungstate chelating agents have been synthesized and characterized. The infrared (IR) and X-ray crystal structures of the complexes revealed that the (MS(4)(2-)) cores had approximate T(d) symmetry in the choline (Ch) salts and C(2v) symmetry in the acetylcholine (AcCh) salts. The AcCh salts hydrolyzed more slowly than the ammonium or Ch salts and the tetrathiotungstate salts hydrolyzed approximately two orders of magnitude more slowly than the tetrathiomolybdate salts. The slower hydrolysis of tetrathiotungstate may make it more useful as an inorganic reagent and therapeutic agent.
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Affiliation(s)
- Victoria E Lee
- Chemistry Department, Princeton University, Princeton, NJ, USA
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80
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Watt NT, Routledge MN, Wild CP, Hooper NM. Cellular prion protein protects against reactive-oxygen-species-induced DNA damage. Free Radic Biol Med 2007; 43:959-67. [PMID: 17697940 DOI: 10.1016/j.freeradbiomed.2007.06.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Revised: 04/26/2007] [Accepted: 06/05/2007] [Indexed: 11/26/2022]
Abstract
Although the cellular form of the prion protein (PrPC) is critical for the development of prion disease through its conformational conversion into the infectious form (PrPSc), the physiological role of PrPC is less clear. Using alkaline single-cell gel electrophoresis (the Comet assay), we show that expression of PrPC protects human neuroblastoma SH-SY5Y cells against DNA damage under basal conditions and following exposure to reactive oxygen species, either hydroxyl radicals following exposure to Cu2+ or Fe2+ or singlet oxygen following exposure to the photosensitizer methylene blue and white light. Cells expressing either PrPDeltaoct which lacks the octapeptide repeats or the prion-disease-associated mutants A116V or PG14 had increased levels of DNA damage compared to cells expressing PrPC. In PrPSc-infected mouse ScN2a cells there was a significant increase in DNA damage over noninfected N2a cells (median tail DNA 2.87 and 7.33%, respectively). Together, these data indicate that PrPC has a critical role to play in protecting cells against reactive-oxygen-species-mediated DNA damage; a function which requires the octapeptide repeats in the protein, is lost in disease-associated mutants of the protein or upon conversion to PrPSc, and thus provide further support for the neuroprotective role for PrPC.
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Affiliation(s)
- Nicole T Watt
- Proteolysis Research Group, Institute of Molecular and Cellular Biology, Faculty of Biological Sciences and Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT, UK
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81
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Lo RYY, Shyu WC, Lin SZ, Wang HJ, Chen SS, Li H. New Molecular Insights into Cellular Survival and Stress Responses: Neuroprotective Role of Cellular Prion Protein (PrPC). Mol Neurobiol 2007; 35:236-44. [DOI: 10.1007/s12035-007-8003-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Revised: 11/30/1999] [Accepted: 11/09/2006] [Indexed: 10/22/2022]
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82
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Kimata A, Nakagawa H, Ohyama R, Fukuuchi T, Ohta S, Doh-ura K, Suzuki T, Miyata N. New series of antiprion compounds: pyrazolone derivatives have the potent activity of inhibiting protease-resistant prion protein accumulation. J Med Chem 2007; 50:5053-6. [PMID: 17850126 DOI: 10.1021/jm070688r] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To find effective antiprion compounds, we synthesized and evaluated various pyrazolone derivatives. Seven of 19 compounds showed inhibition of PrP-res accumulation and the remarkably active compound 13 showed an IC50 value of 3 nM in both ScN2a and F3 cell lines. Findings from studies on physicochemical and biochemical properties suggest that the action mechanism of these compounds does not correlate with any antioxidant activities, any of hydroxyl radical scavenging activities, or any SOD-like activities.
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Affiliation(s)
- Ayako Kimata
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1, Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan
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83
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Lee KJ, Panzera A, Rogawski D, Greene LE, Eisenberg E. Cellular prion protein (PrPC) protects neuronal cells from the effect of huntingtin aggregation. J Cell Sci 2007; 120:2663-71. [PMID: 17635996 DOI: 10.1242/jcs.004598] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The effect of normal cellular prion protein (PrP(C)) on abnormal protein aggregation was examined by transfecting huntingtin fragments (Htt) into SN56 neuronal-derived cells depleted of PrP(C) by RNA interference. PrP(C) depletion caused an increase in both the number of cells containing granules and the number of apoptotic cells. Consistent with the increase in Htt aggregation, PrP(C) depletion caused an decrease in proteasome activity and a decrease in the activities of cellular defense enzymes compared with control cells whereas reactive oxygen species (ROS) increased more than threefold. Therefore, PrP(C) may protect against Htt toxicity in neuronal cells by increasing cellular defense proteins, decreasing ROS and increasing proteasome activity thereby increasing Htt degradation. Depletion of endogenous PrP(C) in non-neuronal Caco-2 and HT-29 cells did not affect ROS levels or proteasome activity suggesting that only in neuronal cells does PrP(C) confer protection against Htt toxicity. The protective effect of PrP(C) was further evident in that overexpression of mouse PrP(C) in SN56 cells transfected with Htt caused a decrease in both the number of cells with Htt granules and the number of apoptotic cells, whereas there was no effect of PrP(C) expression in non-neuronal NIH3T3 or CHO cells. Finally, in chronically scrapie (PrP(Sc))-infected cells, ROS increased more than twofold while proteasome activity was decreased compared to control cells. Although this could be a direct effect of PrP(Sc), it is also possible that, since PrP(C) specifically prevents pathological protein aggregation in neuronal cells, partial loss of PrP(C) itself increases PrP(Sc) aggregation.
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Affiliation(s)
- Kyung-Jin Lee
- Laboratory of Cell Biology, NHBLI, NIH, Bethesda, MD 20892-0301, USA
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84
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Kuwata K, Nishida N, Matsumoto T, Kamatari YO, Hosokawa-Muto J, Kodama K, Nakamura HK, Kimura K, Kawasaki M, Takakura Y, Shirabe S, Takata J, Kataoka Y, Katamine S. Hot spots in prion protein for pathogenic conversion. Proc Natl Acad Sci U S A 2007; 104:11921-6. [PMID: 17616582 PMCID: PMC1924567 DOI: 10.1073/pnas.0702671104] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Prion proteins are key molecules in transmissible spongiform encephalopathies (TSEs), but the precise mechanism of the conversion from the cellular form (PrP(C)) to the scrapie form (PrP(Sc)) is still unknown. Here we discovered a chemical chaperone to stabilize the PrP(C) conformation and identified the hot spots to stop the pathogenic conversion. We conducted in silico screening to find compounds that fitted into a "pocket" created by residues undergoing the conformational rearrangements between the native and the sparsely populated high-energy states (PrP*) and that directly bind to those residues. Forty-four selected compounds were tested in a TSE-infected cell culture model, among which one, 2-pyrrolidin-1-yl-N-[4-[4-(2-pyrrolidin-1-yl-acetylamino)-benzyl]-phenyl]-acetamide, termed GN8, efficiently reduced PrP(Sc). Subsequently, administration of GN8 was found to prolong the survival of TSE-infected mice. Heteronuclear NMR and computer simulation showed that the specific binding sites are the A-S2 loop (N159) and the region from helix B (V189, T192, and K194) to B-C loop (E196), indicating that the intercalation of these distant regions (hot spots) hampers the pathogenic conversion process. Dynamics-based drug discovery strategy, demonstrated here focusing on the hot spots of PrP(C), will open the way to the development of novel anti-prion drugs.
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Affiliation(s)
- Kazuo Kuwata
- Center for Emerging Infectious Diseases, Department of Gene and Development, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1194, Japan.
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85
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New Molecular Insights into Cellular Survival and Stress Responses: Neuroprotective Role of Cellular Prion Protein (PrPC). Mol Neurobiol 2007. [DOI: 10.1007/s12035-007-0011-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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86
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Diez M, Groth D, DeArmond SJ, Prusiner SB, Hökfelt T. Changes in neuropeptide expression in mice infected with prions. Neurobiol Aging 2007; 28:748-65. [PMID: 16621165 DOI: 10.1016/j.neurobiolaging.2006.02.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 02/24/2006] [Accepted: 02/28/2006] [Indexed: 10/24/2022]
Abstract
Prion diseases are neurodegenerative disorders characterized by accumulation of an aberrantly folded isoform (PrP(Sc)) of the normal prion protein (PrP(C)). Using in situ hybridization and immunohistochemistry, we have studied changes in the expression of neuropeptides, acetylcholinesterase and tyrosine hydroxylase in CD1 and FVB wild-type mouse strains, as well as in PrP(C) null mice and in mice overexpressing PrP(C) following intracerebral inoculation with RML or Me7 prions. In the immunohistochemical analysis, neuropeptide Y (NPY), enkephalin and dynorphin-like immunoreactivities increased in mossy fibers of CD1 and FVB mice inoculated with either RML- or Me7 prions, whereas cholecystokinin-like immunoreactivity was decreased. These changes in peptide levels were paralleled by an increase in the transcripts in granule cells for neuropeptide Y, enkephalin, and cholecystokinin. However, the dynorphin transcript was decreased in the granule cells. The changes occurred more rapidly in PrP(C)-overexpressing compared to wild-type mice, and could not be found at all in PrP(C)-knockout mice. These changes in peptide expression, which mostly occur before appearance of symptoms of disease, may reflect attempts to initiate protective and/or regenerative processes.
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Affiliation(s)
- Margarita Diez
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden.
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87
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Maas E, Geissen M, Groschup MH, Rost R, Onodera T, Schätzl H, Vorberg IM. Scrapie infection of prion protein-deficient cell line upon ectopic expression of mutant prion proteins. J Biol Chem 2007; 282:18702-10. [PMID: 17468101 DOI: 10.1074/jbc.m701309200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of the cellular prion protein (PrP(C)) is crucial for susceptibility to prions. In vivo, ectopic expression of PrP(C) restores susceptibility to prions and transgenic mice that express heterologous PrP on a PrP knock-out background have been used extensively to study the role of PrP alterations for prion transmission and species barriers. Here we report that prion protein knock-out cells can be rendered permissive to scrapie infection by the ectopic expression of PrP. The system was used to study the influence of sheep PrP-specific residues in mouse PrP on the infection process with mouse adapted scrapie. These studies reveal several critical residues previously not associated with species barriers and demonstrate that amino acid residue alterations at positions known to have an impact on the susceptibility of sheep to sheep scrapie also drastically influence PrP(Sc) formation by mouse-adapted scrapie strain 22L. Furthermore, our data suggest that amino acid polymorphisms located on the outer surfaces of helix 2 and 3 drastically impact conversion efficiency. In conclusion, this system allows for the fast generation of mutant PrP(Sc) that is entirely composed of transgenic PrP and is, thus, ideally suited for testing if artificial PrP molecules can affect prion replication. Transmission of infectivity generated in HpL3-4 cells expressing altered PrP molecules to mice could also help to unravel the potential influence of mutant PrP(Sc) on host cell tropism and strain characteristics in vivo.
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Affiliation(s)
- Elke Maas
- Institute of Virology, Technical University of Munich, Troger Strasse 30, 81675 Munich, Germany
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88
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Redecke L, von Bergen M, Clos J, Konarev PV, Svergun DI, Fittschen UEA, Broekaert JAC, Bruns O, Georgieva D, Mandelkow E, Genov N, Betzel C. Structural characterization of β-sheeted oligomers formed on the pathway of oxidative prion protein aggregation in vitro. J Struct Biol 2007; 157:308-20. [PMID: 17023178 DOI: 10.1016/j.jsb.2006.06.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2006] [Revised: 06/16/2006] [Accepted: 06/19/2006] [Indexed: 11/26/2022]
Abstract
The pathology of transmissible spongiform encephalopathies (TSEs) is strongly associated with the structural conversion of the cellular prion protein (PrPC) into a misfolded isoform (PrPSc) that assembles into amyloid fibrils. Since increased levels of oxidative stress have been linked to prion diseases, we investigated the metal-induced oxidation of human PrP (90-231). A novel in vitro conversion assay based on aerobic incubation of PrP in the presence of elemental copper pellets at pH 5 was established, resulting in aggregation of highly beta-sheeted prion proteins. We show for the first time that two discrete oligomeric species of elongated shape, approx. 25 mers and 100 mers, are formed on the pathway of oxidative PrP aggregation in vitro, which are well characterized regarding shape and size using small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and electron microscopy (EM). Considering that small oligomers of highly similar size have recently been reported to show the highest specific infectivity within TSE-infected brain tissues of hamsters, the novel oligomers observed in this study are interesting candidates as agent causing neurodegenerative and/or self-propagating effects. Moreover, our results significantly strengthen the theory that oxidative stress might be an influence that leads to substantial structural conversions of PrP in vivo.
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Affiliation(s)
- Lars Redecke
- Center of Experimental Medicine, Institute of Biochemistry and Molecular Biology I, University Hospital Hamburg-Eppendorf, c/o DESY, 22603 Hamburg, Germany
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Farooqui AA, Ong WY, Horrocks LA. Inhibitors of brain phospholipase A2 activity: their neuropharmacological effects and therapeutic importance for the treatment of neurologic disorders. Pharmacol Rev 2006; 58:591-620. [PMID: 16968951 DOI: 10.1124/pr.58.3.7] [Citation(s) in RCA: 236] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The phospholipase A(2) family includes secretory phospholipase A(2), cytosolic phospholipase A(2), plasmalogen-selective phospholipase A(2), and calcium-independent phospholipase A(2). It is generally thought that the release of arachidonic acid by cytosolic phospholipase A(2) is the rate-limiting step in the generation of eicosanoids and platelet activating factor. These lipid mediators play critical roles in the initiation and modulation of inflammation and oxidative stress. Neurological disorders, such as ischemia, spinal cord injury, Alzheimer's disease, multiple sclerosis, prion diseases, and epilepsy are characterized by inflammatory reactions, oxidative stress, altered phospholipid metabolism, accumulation of lipid peroxides, and increased phospholipase A(2) activity. Increased activities of phospholipases A(2) and generation of lipid mediators may be involved in oxidative stress and neuroinflammation associated with the above neurological disorders. Several phospholipase A(2) inhibitors have been recently discovered and used for the treatment of ischemia and other neurological diseases in cell culture and animal models. At this time very little is known about in vivo neurochemical effects, mechanism of action, or toxicity of phospholipase A(2) inhibitors in human or animal models of neurological disorders. In kainic acid-mediated neurotoxicity, the activities of phospholipase A(2) isoforms and their immunoreactivities are markedly increased and phospholipase A(2) inhibitors, quinacrine and chloroquine, arachidonyl trifluoromethyl ketone, bromoenol lactone, cytidine 5-diphosphoamines, and vitamin E, not only inhibit phospholipase A(2) activity and immunoreactivity but also prevent neurodegeneration, suggesting that phospholipase A(2) is involved in the neurodegenerative process. This also suggests that phospholipase A(2) inhibitors can be used as neuroprotectants and anti-inflammatory agents against neurodegenerative processes in neurodegenerative diseases.
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Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
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90
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Chai B, Li JY, Zhang W, Newman E, Ammori J, Mulholland MW. Melanocortin-4 receptor-mediated inhibition of apoptosis in immortalized hypothalamic neurons via mitogen-activated protein kinase. Peptides 2006; 27:2846-57. [PMID: 16806584 DOI: 10.1016/j.peptides.2006.05.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 05/02/2006] [Accepted: 05/03/2006] [Indexed: 11/25/2022]
Abstract
The melanocortin-4 receptor (MC4R) is a seven transmembrane member of the melanocortin receptor family. The GT1-1 cell line exhibits endogenous expression of MC4R. In this study, GT1-1 cells were used to study MC4R signaling pathways and to examine the effects of melanocortin receptor agonist NDP-MSH on apoptosis. MC4R mRNA expression was demonstrated by RT-PCR. Functional melanocortin receptor expression was implied by specific binding of NDP-MSH and cAMP production. NDP-MSH-stimulated GnRH release in a dose-dependent manner. Serum deprivation-induced apoptosis in GT1-1 cells, and the NDP-MSH inhibited this effect. The melanocortin receptor antagonist SHU9119 blocked the antiapoptotic actions of NDP-MSH, and the MAP kinase inhibitor PD98059 significantly attenuated the antiapoptotic effect. NDP-MSH-stimulated ERK1/2 phosphorylation in a dose-dependent manner. ERK1/2 phosphorylation could be abolished by SHU9119. In GT1-1 cells, melanocortin receptor activation causes ERK1/2 phosphorylation. In these cells, MC4R activation is also associated with antiapoptotic effects.
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Affiliation(s)
- Biaoxin Chai
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA
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91
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Ishikawa K, Kudo Y, Nishida N, Suemoto T, Sawada T, Iwaki T, Doh-ura K. Styrylbenzoazole derivatives for imaging of prion plaques and treatment of transmissible spongiform encephalopathies. J Neurochem 2006; 99:198-205. [PMID: 16987247 DOI: 10.1111/j.1471-4159.2006.04035.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent prevalence of acquired forms of transmissible spongiform encephalopathies (TSEs) has urged the development of early diagnostic measures as well as therapeutic interventions. To extend our previous findings on the value of amyloid imaging probes for these purposes, styrylbenzoazole derivatives with better permeability of blood-brain barrier (BBB) were developed and analyzed in this study. The new styrylbenzoazole compounds clearly labeled prion protein (PrP) plaques in brain specimens from human TSE in a manner irrespective of pathogen strain, and a representative compound BF-168 detected abnormal PrP aggregates in the brain of TSE-infected mice when the probe was injected intravenously. On the other hand, most of the compounds inhibited abnormal PrP formation in TSE-infected cells with IC50 values in the nanomolar range, indicating that they represent one of the most potent classes of inhibitor ever reported. BF-168 prolonged the lives of mice infected intracerebrally with TSE when the compound was given intravenously at the preclinical stage. The new compounds, however, failed to detect synaptic PrP deposition and to show pathogen-independent therapeutic efficacy, similar to the amyloid imaging probes we previously reported. The compounds were BBB permeable and non-toxic at doses for imaging and treatment; therefore, they are expected to be of practical use in human TSE.
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Affiliation(s)
- Kensuke Ishikawa
- Division of Prion Biology, Department of Prion Research, Tohoku University Graduate School of Medicine, Sendai, Japan.
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92
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Metal complexes with superoxide dismutase-like activity as candidates for anti-prion drug. Bioorg Med Chem Lett 2006; 16:5982-7. [PMID: 16987659 DOI: 10.1016/j.bmcl.2006.08.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 08/29/2006] [Accepted: 08/30/2006] [Indexed: 10/24/2022]
Abstract
Various compounds were evaluated for ability to inhibit the formation of the abnormal protease-resistant form of prion protein (PrP-res) in two cell lines infected with different prion strains. Examination of the structure-activity relationships indicated that compounds with copper-selective chelating ability and whose copper complexes have high SOD-like activity are candidates for anti-prion drug.
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93
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Vasiljevic S, Ren J, Yao Y, Dalton K, Adamson CS, Jones IM. Green fluorescent protein as a reporter of prion protein folding. Virol J 2006; 3:59. [PMID: 16939649 PMCID: PMC1560372 DOI: 10.1186/1743-422x-3-59] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 08/29/2006] [Indexed: 12/15/2022] Open
Abstract
Background The amino terminal half of the cellular prion protein PrPc is implicated in both the binding of copper ions and the conformational changes that lead to disease but has no defined structure. However, as some structure is likely to exist we have investigated the use of an established protein refolding technology, fusion to green fluorescence protein (GFP), as a method to examine the refolding of the amino terminal domain of mouse prion protein. Results Fusion proteins of PrPc and GFP were expressed at high level in E.coli and could be purified to near homogeneity as insoluble inclusion bodies. Following denaturation, proteins were diluted into a refolding buffer whereupon GFP fluorescence recovered with time. Using several truncations of PrPc the rate of refolding was shown to depend on the prion sequence expressed. In a variation of the format, direct observation in E.coli, mutations introduced randomly in the PrPc protein sequence that affected folding could be selected directly by recovery of GFP fluorescence. Conclusion Use of GFP as a measure of refolding of PrPc fusion proteins in vitro and in vivo proved informative. Refolding in vitro suggested a local structure within the amino terminal domain while direct selection via fluorescence showed that as little as one amino acid change could significantly alter folding. These assay formats, not previously used to study PrP folding, may be generally useful for investigating PrPc structure and PrPc-ligand interaction.
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Affiliation(s)
- Snezana Vasiljevic
- School of Animal and Microbial Sciences, The University of Reading, Reading RG6 6AJ, UK
| | - Junyuan Ren
- School of Animal and Microbial Sciences, The University of Reading, Reading RG6 6AJ, UK
| | - YongXiu Yao
- School of Animal and Microbial Sciences, The University of Reading, Reading RG6 6AJ, UK
| | - Kevin Dalton
- School of Animal and Microbial Sciences, The University of Reading, Reading RG6 6AJ, UK
| | - Catherine S Adamson
- School of Animal and Microbial Sciences, The University of Reading, Reading RG6 6AJ, UK
| | - Ian M Jones
- School of Animal and Microbial Sciences, The University of Reading, Reading RG6 6AJ, UK
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94
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Abstract
The prion protein is a membrane tethered glycoprotein that binds copper. Conversion to an abnormal isoform is associated with neurodegenerative diseases known as prion diseases. Expression of the prion protein has been suggested to prevent cell death caused by oxidative stress. Using cell based models we investigated the potential of the prion protein to protect against copper toxicity. Although prion protein expression effectively protected neurones from copper toxicity, this protection was not necessarily associated with reduction in oxidative damage. We also showed that glycine and the prion protein could both protect neuronal cells from oxidative stress. Only the prion protein could protect these cells from the toxicity of copper. In contrast glycine increased copper toxicity without any apparent oxidative stress or lipid peroxidation. Mutational analysis showed that protection by the prion protein was dependent upon the copper binding octameric repeat region. Our findings demonstrate that copper toxicity can be independent of measured oxidative stress and that prion protein expression primarily protects against copper toxicity independently of the mechanism of cell death.
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Affiliation(s)
- Cathryn L Haigh
- Department of Biology and Biochemistry, University of Bath, Bath, UK
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95
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Walker LC, Levine H, Mattson MP, Jucker M. Inducible proteopathies. Trends Neurosci 2006; 29:438-43. [PMID: 16806508 PMCID: PMC10725716 DOI: 10.1016/j.tins.2006.06.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Revised: 03/07/2006] [Accepted: 06/08/2006] [Indexed: 12/31/2022]
Abstract
Numerous degenerative diseases are characterized by the aberrant polymerization and accumulation of specific proteins. These proteopathies include neurological disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease and the prion diseases, in addition to diverse systemic disorders, particularly the amyloidoses. The prion diseases have been shown to be transmissible by an alternative conformation of the normal cellular prion protein. Other proteopathies have been thought to be non-transmissible, but there is growing evidence that some systemic and cerebral amyloidoses can be induced by exposure of susceptible hosts to cognate molecular templates. As we review here, the mechanistic similarities among these diseases provide unprecedented opportunities for elucidating the induction of protein misfolding and assembly in vivo, and for developing an integrated therapeutic approach to degenerative proteopathies.
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Affiliation(s)
- Lary C Walker
- Yerkes National Primate Research Center and Department of Neurology, Emory University, Atlanta, GA 30322, USA.
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96
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Sanvicens N, Gómez-Vicente V, Messeguer A, Cotter TG. The radical scavenger CR-6 protects SH-SY5Y neuroblastoma cells from oxidative stress-induced apoptosis: effect on survival pathways. J Neurochem 2006; 98:735-47. [PMID: 16787420 DOI: 10.1111/j.1471-4159.2006.03914.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Reactive oxygen species (ROS) and oxidative stress have long been linked to cell death of neurons in many neurodegenerative conditions. However, the exact molecular mechanisms triggered by oxidative stress in neurodegeneration are at present unclear. In the current work we have used the human neuroblastoma SH-SY5Y cell line as a model for studying the molecular events occurring after inducing apoptosis with H2O2. We show that treatment of SH-SY5Y cells with H2O2 up-regulates survival pathways during early stages of apoptosis. Subsequently, the decline of anti-apoptotic protein levels leads to the activation of the calcium-dependent proteases calpains and the cysteine proteases caspases. Additionally, we demonstrate that CR-6 (3,4-dihydro-6-hydroxy-7-methoxy-2,2-dimethyl-1(2H)-benzopyran) acts as a scavenger of ROS and prevents apoptosis by enhancing and prolonging up-regulation of survival pathways. Furthermore, we show that pre-treatment of SH-SY5Y cells with a cocktail containing CR-6, the pan-caspase inhibitor zVAD-fmk (zVal-Ala-Asp-fluoro-methylketone) and the calpain inhibitor SJA6017 confers almost total protection against apoptosis. In summary, the present work characterizes the molecular mechanisms involved in oxidative stress-induced apoptosis in SH-SY5Y cells. Our findings highlight the relevance of CR-6, alone or in combination with other drugs, as potential therapeutic strategy for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Nuria Sanvicens
- Cell Development and Disease Laboratory, Department of Biochemistry, Biosciences Research Institute, University College Cork, Cork, Ireland
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97
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Tsiroulnikov K, Rezaei H, Dalgalarrondo M, Chobert JM, Grosclaude J, Haertlé T. Cu(II) induces small-size aggregates with amyloid characteristics in two alleles of recombinant ovine prion proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2006; 1764:1218-26. [PMID: 16777497 DOI: 10.1016/j.bbapap.2006.04.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 03/20/2006] [Accepted: 04/04/2006] [Indexed: 11/26/2022]
Abstract
One of symptoms of transmissible spongiform encephalopathies is associated with the transformation of normal cellular prion protein, PrP, in its amyloid isoform resistant to proteolytic cleavage. The present study shows that interaction with copper ions converts both monomeric recombinant scrapie-susceptible PrP-VRQ and scrapie-resistant PrP-ARR variants into protease-resistant soluble oligomers with amyloid characteristics -- dominant beta-sheet secondary structure and interaction with thioflavine S. In contrast, binding of zinc ions resulting in the same resistance to proteolysis does not provoke transformation of alpha-helical monomeric structure of both PrP polymorphic variants. Cleavage of PrP N-terminus destabilises soluble form of such aggregates, and N-truncated PrPrec complexed with metal cations precipitate. N-truncated PrPrec complexed with Zn precipitated much faster than N-truncated PrPrec complexed with Cu. According to the hypothesis about the key role of small PrP oligomers in PrP(C)-PrP(Sc) transformation, formation of soluble oligomers of PrP complexed with Cu can constitute an additional element in TSE propagation. Identical metal-chelating behaviour of two studied polymorphic PrPrec variants conferring different susceptibilities of sheep to scrapie could indicate their different capabilities to form fibrils. This could imply also that other factors than physico-chemical differences between PrP-VRQ and PrP-ARR and the differences in PrP transformation are responsible for the onset of TSE.
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Affiliation(s)
- Kirill Tsiroulnikov
- Institut National de la Recherche Agronomique, BIA-FIPL, B.P. 71627, F-44316 Nantes Cedex 3, France
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98
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Tsiroulnikov K, Chobert JM, Haertlé T. Copper-dependent degradation of recombinant ovine prion protein. Phosphatidylinositol stimulates aggregation and copper-driven disappearance of prion protein. FEBS J 2006; 273:1959-65. [PMID: 16640559 DOI: 10.1111/j.1742-4658.2006.05209.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Prion protein (PrP) plays an important role in cell protection from oxidative stress due to its action as copper-chelating protein. The present study demonstrates that PrP participates in reductions of Cu2+ to Cu+ ions, and that this process results in fragmentation of protein. The interaction with phosphatidylinositol, a natural phospholipid moiety bound to PrP, strongly enhances recombinant PrP aggregation and degradation. The copper-dependent PrP degradation could promote the formation of amyloid structures, destabilizing the PrP soluble form by the cleavage of the N-terminal part.
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99
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Amselgruber WM, Steffl M, Didier A, Märtlbauer E, Pfaff E, Büttner M. Prion protein expression in bovine podocytes and extraglomerular mesangial cells. Cell Tissue Res 2006; 324:497-505. [PMID: 16485135 DOI: 10.1007/s00441-005-0128-6] [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] [Received: 07/25/2005] [Accepted: 10/15/2005] [Indexed: 10/25/2022]
Abstract
The cellular form of the prion protein (PrP(c)) is thought to be a substrate for an abnormal isoform of the prion protein (PrP(sc)). One emerging hypothesis is that the proposed conversion phenomenon takes place at the site at which the infectious agent meets PrP(c). PrP(c) is abundant in the central nervous system, but little is known about the cell-type-specific distribution of PrP(c) in non-neuronal tissues of cattle. We have studied whether PrP(c), a protein found predominantly in neurons, also exists in bovine podocytes, since neurons and podocytes share a large number of similarities. We have therefore examined the expression of PrP(c) by immunohistochemistry, reverse transcription/polymerase chain reaction and enzyme-linked immunosorbent analysis. Immunostained serial sections and specific antibodies against PrP(c) have revealed that PrP(c) is selectively localized in podocytes and is particularly strongly expressed in extraglomerular mesangial cells but not in endothelial or intraglomerular mesangial cells. The selective expression of PrP(c) in podocytes is of special importance, as it suggests that these cells represent possible targets for peripheral infection with prions and demonstrates that PrP(c) can be added to the list of neuronal factors expressed in mammalian podocytes.
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Affiliation(s)
- W M Amselgruber
- Institute of Anatomy and Physiology, University of Hohenheim, Fruhwirthstrasse 35, 70593 Stuttgart, Germany.
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100
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Deloncle R, Guillard O, Bind JL, Delaval J, Fleury N, Mauco G, Lesage G. Free radical generation of protease-resistant prion after substitution of manganese for copper in bovine brain homogenate. Neurotoxicology 2006; 27:437-44. [PMID: 16481041 DOI: 10.1016/j.neuro.2006.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2005] [Revised: 12/24/2005] [Accepted: 01/05/2006] [Indexed: 10/25/2022]
Abstract
The exchange between copper and seven transition metals is studied in a bovine brain obex homogenate according to the redox status of the medium. In reductive conditions, almost all the studied metals can substitute for copper when it is in the reduced form Cu+. This substitution is reversible, since copper uptake as Cu++ is restored in an oxidizing medium but only Co++, Ni++ and Mn++, in this decreasing order, can substitute perfectly for copper in bovine brain homogenate. To study free radical effects on bovine brain proteins, at first a copper substitution was processed in order to inhibit superoxide dismutase-like protective properties against free radicals in copper metalloproteins. Manganese was selected since a brain copper decrease correlated with a manganese increase is well-known in transmissible spongiform encephalopathies. Results for bovine brain homogenate, initially negative in the Western blot Prionics test, indicate that the substitution of manganese for copper in a reducing medium and exposure to UVA-induced free radicals produce proteinase K resistant prion. These findings suggest that an impairment in brain metal homeostasis leading to oxidative abnormalities may be involved in transmissible spongiform encephalopathies.
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Affiliation(s)
- Roger Deloncle
- Université François Rabelais de Tours, Bio-Inorganic Chemistry Laboratory, Faculty of Pharmacy, 31 Avenue Monge, 37200 Tours, France.
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