451
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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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452
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Rambold AS, Miesbauer M, Rapaport D, Bartke T, Baier M, Winklhofer KF, Tatzelt J. Association of Bcl-2 with misfolded prion protein is linked to the toxic potential of cytosolic PrP. Mol Biol Cell 2006; 17:3356-68. [PMID: 16707568 PMCID: PMC1525242 DOI: 10.1091/mbc.e06-01-0083] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 04/17/2006] [Accepted: 05/10/2006] [Indexed: 01/07/2023] Open
Abstract
Protein misfolding is linked to different neurodegenerative disorders like Alzheimer's disease, polyglutamine, and prion diseases. We investigated the cytotoxic effects of aberrant conformers of the prion protein (PrP) and show that toxicity is specifically linked to misfolding of PrP in the cytosolic compartment and involves binding of PrP to the anti-apoptotic protein Bcl-2. PrP targeted to different cellular compartments, including the cytosol, nucleus, and mitochondria, adopted a misfolded and partially proteinase K-resistant conformation. However, only in the cytosol did the accumulation of misfolded PrP induce apoptosis. Apoptotic cell death was also induced by two pathogenic mutants of PrP, which are partially localized in the cytosol. A mechanistic analysis revealed that the toxic potential is linked to an internal domain of PrP (amino acids 115-156) and involves coaggregation of cytosolic PrP with Bcl-2. Increased expression of the chaperones Hsp70 and Hsp40 prevented the formation of PrP/Bcl-2 coaggregates and interfered with PrP-induced apoptosis. Our study reveals a compartment-specific toxicity of PrP misfolding that involves coaggregation of Bcl-2 and indicates a protective role of molecular chaperones.
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Affiliation(s)
- Angelika S. Rambold
- *Department of Biochemistry, Neurobiochemistry, Ludwig-Maximilians-Universität München, D-80336 München, Germany
| | - Margit Miesbauer
- *Department of Biochemistry, Neurobiochemistry, Ludwig-Maximilians-Universität München, D-80336 München, Germany
| | - Doron Rapaport
- Institut für Physiologische Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Till Bartke
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom; and
| | | | - Konstanze F. Winklhofer
- *Department of Biochemistry, Neurobiochemistry, Ludwig-Maximilians-Universität München, D-80336 München, Germany
| | - Jörg Tatzelt
- *Department of Biochemistry, Neurobiochemistry, Ludwig-Maximilians-Universität München, D-80336 München, Germany
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453
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Morris RJ, Parkyn CJ, Jen A. Traffic of prion protein between different compartments on the neuronal surface, and the propagation of prion disease. FEBS Lett 2006; 580:5565-71. [PMID: 16884720 DOI: 10.1016/j.febslet.2006.07.053] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 07/07/2006] [Accepted: 07/12/2006] [Indexed: 12/11/2022]
Abstract
The key mechanism in prion disease is the conversion of cellular prion protein into an altered, pathogenic conformation, in which cellular mechanisms play a poorly understood role. Both forms of prion protein are lipid-anchored and reside in rafts that appear to protect the native conformation against conversion. Neurons rapidly traffic their cellular prion protein out of its lipid rafts to be endocytosed via coated pits before recycling back to the cell surface. It is argued in this review that understanding the mechanism of this trafficking holds the key to understanding the cellular role in the conformational conversion of prion protein.
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Affiliation(s)
- Roger J Morris
- Wolfson Centre for Age-Related Diseases, Guy's Hospital Campus, King's College, London SE1 1UL, United Kingdom.
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454
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Baskakov IV, Breydo L. Converting the prion protein: what makes the protein infectious. Biochim Biophys Acta Mol Basis Dis 2006; 1772:692-703. [PMID: 16935473 DOI: 10.1016/j.bbadis.2006.07.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Revised: 07/07/2006] [Accepted: 07/19/2006] [Indexed: 02/08/2023]
Abstract
The discovery of prion disease transmission in mammals, as well as a non-Mendelian type of inheritance in yeast, has led to the establishment of a new concept in biology, the prion hypothesis. The prion hypothesis postulates that an abnormal protein conformation propagates itself in an autocatalytic manner via recruitment of the normal isoform of the same protein as a substrate, and thereby acts either as a transmissible agent of disease (in mammals) or as a heritable determinant of phenotype (in yeast and fungus). Although reconstitution of fully infectious PrP(Sc)in vitro from synthetic components has not yet been achieved, numerous lines of evidence indicate that the prion protein is the major and essential component, if not the only one, of the prion infectious agent. This article summarizes our current knowledge about the chemical nature of the prion infectious agent, describes potential strategies and challenges related to the generation of prion infectivity de novo, proposes new hypotheses to explain the apparently low infectivity observed in the first synthetic mammalian prions, and describes plausible effects of chemical modifications on prion conversion.
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Affiliation(s)
- Ilia V Baskakov
- Medical Biotechnology Center, University of Maryland Biotechnology Institute Baltimore, MD 21201, USA.
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455
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Trifilo MJ, Yajima T, Gu Y, Dalton N, Peterson KL, Race RE, Meade-White K, Portis JL, Masliah E, Knowlton KU, Chesebro B, Oldstone MBA. Prion-induced amyloid heart disease with high blood infectivity in transgenic mice. Science 2006; 313:94-7. [PMID: 16825571 PMCID: PMC1820586 DOI: 10.1126/science.1128635] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We investigated extraneural manifestations in scrapie-infected transgenic mice expressing prion protein lacking the glycophosphatydylinositol membrane anchor. In the brain, blood, and heart, both abnormal protease-resistant prion protein (PrPres) and prion infectivity were readily detected by immunoblot and by inoculation into nontransgenic recipients. The titer of infectious scrapie in blood plasma exceeded 10(7) 50% infectious doses per milliliter. The hearts of these transgenic mice contained PrPres-positive amyloid deposits that led to myocardial stiffness and cardiac disease.
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Affiliation(s)
- Matthew J. Trifilo
- Viral-Immunobiology Laboratory, Departments of Molecular and Integrative Neurosciences and Infectology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Toshitaka Yajima
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yusu Gu
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nancy Dalton
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kirk L. Peterson
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Richard E. Race
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Kimberly Meade-White
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - John L. Portis
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Eliezer Masliah
- Departments of Neurosciences and Pathology, University of California, San Diego, CA 92093, USA
| | - Kirk U. Knowlton
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- *To whom correspondence should be addressed. E-mail: (M.B.A.O.), (B.C.), (K.U.K.)
| | - Bruce Chesebro
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
- *To whom correspondence should be addressed. E-mail: (M.B.A.O.), (B.C.), (K.U.K.)
| | - Michael B. A. Oldstone
- Viral-Immunobiology Laboratory, Departments of Molecular and Integrative Neurosciences and Infectology, Scripps Research Institute, La Jolla, CA 92037, USA
- *To whom correspondence should be addressed. E-mail: (M.B.A.O.), (B.C.), (K.U.K.)
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456
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Pietri M, Caprini A, Mouillet-Richard S, Pradines E, Ermonval M, Grassi J, Kellermann O, Schneider B. Overstimulation of PrPC signaling pathways by prion peptide 106-126 causes oxidative injury of bioaminergic neuronal cells. J Biol Chem 2006; 281:28470-9. [PMID: 16864581 DOI: 10.1074/jbc.m602774200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transmissible spongiform encephalopathies, also called prion diseases, are characterized by neuronal loss linked to the accumulation of PrP(Sc), a pathologic variant of the cellular prion protein (PrP(C)). Although the molecular and cellular bases of PrP(Sc)-induced neuropathogenesis are not yet fully understood, increasing evidence supports the view that PrP(Sc) accumulation interferes with PrP(C) normal function(s) in neurons. In the present work, we exploit the properties of PrP-(106-126), a synthetic peptide encompassing residues 106-126 of PrP, to investigate into the mechanisms sustaining prion-associated neuronal damage. This peptide shares many physicochemical properties with PrP(Sc) and is neurotoxic in vitro and in vivo. We examined the impact of PrP-(106-126) exposure on 1C11 neuroepithelial cells, their neuronal progenies, and GT1-7 hypothalamic cells. This peptide triggers reactive oxygen species overflow, mitogen-activated protein kinase (ERK1/2), and SAPK (p38 and JNK1/2) sustained activation, and apoptotic signals in 1C11-derived serotonergic and noradrenergic neuronal cells, while having no effect on 1C11 precursor and GT1-7 cells. The neurotoxic action of PrP-(106-126) relies on cell surface expression of PrP(C), recruitment of a PrP(C)-Caveolin-Fyn signaling platform, and overstimulation of NADPH-oxidase activity. Altogether, these findings provide actual evidence that PrP-(106-126)-induced neuronal injury is caused by an amplification of PrP(C)-associated signaling responses, which notably promotes oxidative stress conditions. Distorsion of PrP(C) signaling in neuronal cells could hence represent a causal event in transmissible spongiform encephalopathy pathogenesis.
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Affiliation(s)
- Mathéa Pietri
- Différenciation Cellulaire et Prions, CNRS FRE2937, Institut André Lwoff, 7 rue Guy Môquet, 94801 Villejuif Cedex, France
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457
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Walker L, Levine H, Jucker M. Koch's postulates and infectious proteins. Acta Neuropathol 2006; 112:1-4. [PMID: 16703338 PMCID: PMC8544537 DOI: 10.1007/s00401-006-0072-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 03/22/2006] [Accepted: 03/22/2006] [Indexed: 10/24/2022]
Abstract
Koch's postulates were formulated in the late nineteenth century as guidelines for establishing that microbes cause specific diseases. Because the rules were developed for living agents--particularly bacteria--their applicability to inanimate pathogens such as viruses and infectious proteins has been problematic. The unorthodox mechanism by which prion diseases are transmitted, involving specific physicochemical characteristics of the protein as well as susceptibility traits of the host, has made these disorders refractory to analysis within the context of the original Koch's postulates. In addition, evidence is accumulating that other proteopathies, such as AA amyloidosis, apolipoprotein AII amyloidosis, and cerebral Abeta amyloidosis, can be induced in vulnerable recipients by cognate proteinaceous agents. In light of the salient differences in the mode of disease-transmission by microbes and proteins, we propose modifications of Koch's postulates that will specifically accommodate presumed infectious proteins.
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Affiliation(s)
- Lary Walker
- Yerkes National Primate Research Center and Department of Neurology, Emory University, Atlanta, GA, 30322, USA.
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458
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Ronzon F, Rieu JP, Chauvet JP, Roux B. A thermodynamic study of GPI-anchored and soluble form of alkaline phosphatase films at the air-water interface. J Colloid Interface Sci 2006; 301:493-502. [PMID: 16793053 DOI: 10.1016/j.jcis.2006.05.055] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 05/23/2006] [Accepted: 05/25/2006] [Indexed: 11/29/2022]
Abstract
Glycosylphosphatidyl inositol (GPI) anchored proteins are localized and clustered on the outer layer of the plasma membranes forming microdomains. Among them, mammalian alkaline phosphatases (AP-GPI) are widely distributed enzymes. They can also exist as soluble proteins without anchor (APs). Using the Langmuir film technique, we study the thermodynamic properties of monolayers for both protein forms at the air-buffer interface. The enzymatic activity is maintained at the interface but the adsorption of the two forms of AP is very different. AP-GPI presents a higher surface activity and a larger molecular area than the soluble form. The molecular area deduced for high surface pressures suggests a different organization of the monolayers for these two forms. APs molecules seem to adsorb as a multilayer at the interface while AP-GPI appear to be orientated with the major axis parallel to the interface. This orientation allows the accessibility of AP-GPI enzymatic sites that are turned in direction of the subphase as in vivo where the active sites must be turned outside of the membrane.
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Affiliation(s)
- Frédéric Ronzon
- Laboratoire de Physico-Chimie Biologique, UMR 5013, Université Claude Bernard Lyon I, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne cedex, France.
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459
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Castellani RJ, Lee HG, Zhu X, Nunomura A, Perry G, Smith MA. Neuropathology of Alzheimer disease: pathognomonic but not pathogenic. Acta Neuropathol 2006; 111:503-9. [PMID: 16718346 DOI: 10.1007/s00401-006-0071-y] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Revised: 03/29/2006] [Accepted: 03/29/2006] [Indexed: 11/29/2022]
Abstract
Neuropathological changes in subjects with dementia are, by definition, end-stage phenomena. While such changes allow case characterization and lend themselves to disease classification and modeling, the lesions themselves are not etiological. This truth would appear to be self-evident, yet the medical and scientific literature suggests otherwise. Indeed it is now customary to view amyloid plaques in Alzheimer disease as primary etiological, neurotoxic lesions and, hence, removing them (e.g., by immunotherapy) is believed to lead to clinical improvement. The foundation for this line of thinking lies in the existence of rare kindreds with mutations in amyloid-beta, or mutations believed to be involved in the processing of amyloid-beta, and then the extrapolation of the inherited condition to sporadic disease. We believe that this overall construct ignores early events that are more critical to onset and progression of sporadic disease. Likewise, we have studied subjects with sporadic Alzheimer disease, as well as early onset familial Alzheimer disease and Down's syndrome, over a spectrum of ages, and have found that markers of oxidative stress precede amyloid deposits in all three conditions. Amyloid and neurofibrillary pathology in the Alzheimer brain show a decrease in oxidative stress relative to vulnerable but morphologically intact neurons, suggesting that neurodegenerative lesions are compensatory phenomena, and thus manifestations of cellular adaptation. The pathology of neurodegenerative diseases should be viewed as the end-stage consequence, as opposed to cause, of the disease processes, so that early disease processes that are amenable to intervention can be properly recognized and treated.
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Affiliation(s)
- Rudy J Castellani
- Department of Pathology (Neuropathology), University of Maryland, Baltimore, MD, USA
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460
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Abstract
Prions are the causative agent of the transmissible spongiform encephalopathies, such as Creutzfeldt-Jakob disease in humans. In these prion diseases the normal cellular form of the prion protein (PrP(C)) undergoes a post-translational conformational conversion to the infectious form (PrP(Sc)). PrP(C) associates with cholesterol- and glycosphingolipid-rich lipid rafts through association of its glycosyl-phosphatidylinositol (GPI) anchor with saturated raft lipids and through interaction of its N-terminal region with an as yet unidentified raft associated molecule. PrP(C) resides in detergent-resistant domains that have different lipid and protein compositions to the domains occupied by another GPI-anchored protein, Thy-1. In some cells PrP(C) may endocytose through caveolae, but in neuronal cells, upon copper binding to the N-terminal octapeptide repeats, the protein translocates out of rafts into detergent-soluble regions of the plasma membrane prior to endocytosis through clathrin-coated pits. The current data suggest that the polybasic region at its N-terminus is required to engage PrP(C) with a transmembrane adaptor protein which in turn links with the clathrin endocytic machinery. PrP(C) associates in rafts with a variety of signalling molecules, including caveolin-1 and Fyn and Src tyrosine kinases. The clustering of PrP(C) triggers a range of signal transduction processes, including the recruitment of the neural cell adhesion molecule to rafts which in turn promotes neurite outgrowth. Lipid rafts appear to be involved in the conformational conversion of PrP(C) to PrP(Sc), possibly by providing a favourable environment for this process to occur and enabling disease progression.
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Affiliation(s)
- David R Taylor
- Proteolysis Research Group, Leeds Institute of Genetics, Health and Therapeutics, Faculty of Biological Sciences, University of Leeds, UK
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461
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Novitskaya V, Bocharova OV, Bronstein I, Baskakov IV. Amyloid Fibrils of Mammalian Prion Protein Are Highly Toxic to Cultured Cells and Primary Neurons. J Biol Chem 2006; 281:13828-13836. [PMID: 16554307 DOI: 10.1074/jbc.m511174200] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A growing body of evidence indicates that small, soluble oligomeric species generated from a variety of proteins and peptides rather than mature amyloid fibrils are inherently highly cytotoxic. Here, we show for the first time that mature amyloid fibrils produced from full-length recombinant mammalian prion protein (rPrP) were highly toxic to cultured cells and primary hippocampal and cerebella neurons. Fibrils induced apoptotic cell death in a time- and dose-dependent manner. The toxic effect of fibrils was comparable with that exhibited by soluble small beta-oligomers generated from the same protein. Fibrils prepared from insulin were not toxic, suggesting that the toxic effect was not solely due to the highly polymeric nature of the fibrillar form. The cell death caused by rPrP fibrils or beta-oligomers was substantially reduced when expression of endogenous PrP(C) was down-regulated by small interfering RNAs. In opposition to the beta-oligomer and amyloid fibrils of rPrP, the monomeric alpha-helical form of rPrP stimulated neurite out-growth and survival of neurons. These studies illustrated that both soluble beta-oligomer and amyloid fibrils of the prion protein are intrinsically toxic and confirmed that endogenously expressed PrP(C) is required for mediating the toxicity of abnormally folded external PrP aggregates.
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Affiliation(s)
- Vera Novitskaya
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, Maryland 21201
| | - Olga V Bocharova
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, Maryland 21201
| | - Igor Bronstein
- National Institute for Medical Research, Physical Biochemistry Division, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Ilia V Baskakov
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, Maryland 21201; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
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462
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Abstract
Prion diseases in humans and animals are due to conformational conversion of PrP(C), a cellular glycoprotein of unknown function, into PrP(Sc), an isoform that appears to be infectious in the absence of nucleic acids. Proteins that behave as prions are also found in yeast and filamentous fungi. Although there is now strong experimental support for the hypothesis that prions are infectious proteins, two subjects have remained poorly understood: the structure of prions, and the mechanisms by which they kill neurons. In this review, we will highlight recent studies that shed new light on these important issues.
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Affiliation(s)
- David A Harris
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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463
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Lewis P, Properzi F, Prodromidou K, Clarke A, Collinge J, Jackson G. Removal of the glycosylphosphatidylinositol anchor from PrP(Sc) by cathepsin D does not reduce prion infectivity. Biochem J 2006; 395:443-8. [PMID: 16441239 PMCID: PMC1422754 DOI: 10.1042/bj20051677] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
According to the protein-only hypothesis of prion propagation, prions are composed principally of PrP(Sc), an abnormal conformational isoform of the prion protein, which, like its normal cellular precursor (PrP(C)), has a GPI (glycosylphosphatidylinositol) anchor at the C-terminus. To date, elucidating the role of this anchor on the infectivity of prion preparations has not been possible because of the resistance of PrP(Sc) to the activity of PI-PLC (phosphoinositide-specific phospholipase C), an enzyme which removes the GPI moiety from PrP(C). Removal of the GPI anchor from PrP(Sc) requires denaturation before treatment with PI-PLC, a process that also abolishes infectivity. To circumvent this problem, we have removed the GPI anchor from PrP(Sc) in RML (Rocky Mountain Laboratory)-prion-infected murine brain homogenate using the aspartic endoprotease cathepsin D. This enzyme eliminates a short sequence at the C-terminal end of PrP to which the GPI anchor is attached. We found that this modification has no effect (i) on an in vitro amplification model of PrP(Sc), (ii) on the prion titre as determined by a highly sensitive N2a-cell based bioassay, or (iii) in a mouse bioassay. These results show that the GPI anchor has little or no role in either the propagation of PrP(Sc) or on prion infectivity.
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Affiliation(s)
- Patrick A. Lewis
- *MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, U.K
| | - Francesca Properzi
- *MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, U.K
| | - Kanella Prodromidou
- *MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, U.K
| | - Anthony R. Clarke
- †Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, U.K
| | - John Collinge
- *MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, U.K
| | - Graham S. Jackson
- *MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, U.K
- To whom correspondence should be addressed (email )
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464
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Abstract
A hallmark feature of prions, whether in mammals or yeast and fungi, is exponential growth associated with fission or autocatalysis of protein aggregates. We have employed a rigorous kinetic analysis to recent data from transgenic mice lacking a glycosylphosphatidylinositol membrane anchor to the normal cellular PrP(C) protein, which show that toxicity requires the membrane binding. We find as well that the membrane is necessary for exponential growth of prion aggregates; without it, the kinetics is simply the quadratic-in-time growth characteristic of linear elongation as observed frequently in in vitro amyloid growth experiments with other proteins. This requires both: i), a substantial intercellular concentration of anchorless PrP(C), and ii), a concentration of small scrapies seeding aggregates from the inoculum, which remains relatively constant with time and exceeds the concentration of large polymeric aggregates. We also can explain via this analysis why mice heterozygous for the anchor-full/anchor-free PrP(C) proteins have more rapid incubation than mice heterozygous for anchor-full/null PrP(C), and contrast the mammalian membrane associated fission or autocatalysis with the membrane free fission of yeast and fungal prions.
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Affiliation(s)
- Daniel L Cox
- Department of Physics, University of California-Davis, Davis, CA 95616, USA
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465
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Lührs T, Zahn R, Wüthrich K. Amyloid Formation by Recombinant Full-length Prion Proteins in Phospholipid Bicelle Solutions. J Mol Biol 2006; 357:833-41. [PMID: 16466741 DOI: 10.1016/j.jmb.2006.01.016] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2005] [Revised: 12/29/2005] [Accepted: 01/04/2006] [Indexed: 11/28/2022]
Abstract
A soluble, oligomeric beta-sheet-rich conformational variant of recombinant full-length prion protein, PrP beta, was generated that aggregates into amyloid fibrils, PrP betaf. These fibrils have physico-chemical and structural properties closely similar to those of pathogenic PrP Sc in scrapie-associated fibrils and prion rods, including a closely similar proteinase K digestion pattern and Congo red birefringence. The conformational transition from PrP C to PrP beta occurs at pH 5.0 in bicellar solutions containing equimolar mixtures of dihexanoyl-phosphocholine and dimyristoyl-phospholipids, and a small percentage of negatively charged dimyristoyl-phosphoserine. The same protocol was applicable to human, cow, elk, pig, dog and mouse PrP. Comparison of full-length hPrP 23-230 with the N-terminally truncated human PrP fragments hPrP 90-230, hPrP 96-230, hPrP 105-230 and hPrP 121-230 showed that the flexible peptide segment 105-120 must be present for the generation of PrP beta. Dimerization of PrP C represents the rate-limiting step of the PrP C-to-PrP beta conformational transition, which is dependent on the amino acid sequence. The activation enthalpy of dimerization is about 130 kJ/mol for the recombinant full-length human and bovine prion proteins, and between 260 and 320 kJ/mol for the other species investigated. The in vitro conversion assay described here permits direct molecular characterization of processes that might be closely related to conformational transitions of the prion protein in transmissible spongiform encephalopathies.
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Affiliation(s)
- Thorsten Lührs
- Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
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466
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Steele AD, Emsley JG, Özdinler PH, Lindquist S, Macklis JD. Prion protein (PrPc) positively regulates neural precursor proliferation during developmental and adult mammalian neurogenesis. Proc Natl Acad Sci U S A 2006; 103:3416-21. [PMID: 16492732 PMCID: PMC1413927 DOI: 10.1073/pnas.0511290103] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The misfolding of the prion protein (PrP(c)) is a central event in prion diseases, yet the normal function of PrP(c) remains unknown. PrP(c) has putative roles in many cellular processes including signaling, survival, adhesion, and differentiation. Given the abundance of PrP(c) in the developing and mature mammalian CNS, we investigated the role of PrP(c) in neural development and in adult neurogenesis, which occurs constitutively in the dentate gyrus (DG) of the hippocampus and in the olfactory bulb from precursors in the subventricular zone (SVZ)/rostral migratory stream. In vivo, we find that PrP(c) is expressed immediately adjacent to the proliferative region of the SVZ but not in mitotic cells. In vivo and in vitro studies further find that PrP(c) is expressed in multipotent neural precursors and mature neurons but is not detectable in glia. Loss- and gain-of-function experiments demonstrate that PrP(c) levels correlate with differentiation of multipotent neural precursors into mature neurons in vitro and that PrP(c) levels positively influence neuronal differentiation in a dose-dependent manner. PrP(c) also increases cellular proliferation in vivo; in the SVZ, PrP(c) overexpresser (OE) mice have more proliferating cells compared with wild-type (WT) or knockout (KO) mice; in the DG, PrP(c) OE and WT mice have more proliferating cells compared with KO mice. Our results demonstrate that PrP(c) plays an important role in neurogenesis and differentiation. Because the final number of neurons produced in the DG is unchanged by PrP(c) expression, other factors must control the ultimate fate of new neurons.
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Affiliation(s)
- Andrew D. Steele
- *Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142; and
| | - Jason G. Emsley
- Departments of Neurosurgery and Neurology, Program in Neuroscience, Massachusetts General Hospital–Harvard Medical School Center for Nervous System Repair, and Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02114
| | - P. Hande Özdinler
- Departments of Neurosurgery and Neurology, Program in Neuroscience, Massachusetts General Hospital–Harvard Medical School Center for Nervous System Repair, and Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02114
| | - Susan Lindquist
- *Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142; and
- To whom correspondence may be addressed at:
Whitehead Institute for Biomedical Research, 9 Cambridge Center, Massachusetts Institute of Technology, Cambridge, MA 02142. E-mail:
| | - Jeffrey D. Macklis
- Departments of Neurosurgery and Neurology, Program in Neuroscience, Massachusetts General Hospital–Harvard Medical School Center for Nervous System Repair, and Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02114
- To whom correspondence may be addressed at:
MGH-HMS Center for Nervous System Repair, Massachusetts General Hospital, Edwards 4 (EDR 410), 50 Blossom Street, Boston, MA 02114. E-mail:
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467
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Lee CH, Kim HJ, Lee JH, Cho HJ, Kim J, Chung KC, Jung S, Paik SR. Dequalinium-induced Protofibril Formation of α-Synuclein. J Biol Chem 2006; 281:3463-72. [PMID: 16330551 DOI: 10.1074/jbc.m505307200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
alpha-Synuclein is the major constituent of Lewy bodies, a pathological signature of Parkinson disease, found in the degenerating dopaminergic neurons of the substantia nigra pars compacta. Amyloidosis generating the insoluble fibrillar protein deposition has been considered to be responsible for the cell death observed in the neurodegenerative disorder. In order to develop a controlling strategy toward the amyloid formation, 1,1'-(1,10-decanediyl)-bis-[4-a-mino-2-methylquinolinium] (dequalinium), was selected and examined in terms of its specific molecular interaction with alpha-synuclein. The protein was self-oligomerized by dequalinium, which gave rise to the ladder formation on N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine/SDS-PAGE in the presence of a coupling reagent of N-(ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline. The double-headed structure of dequalinium with the two cationic 4-aminoquinaldinium rings was demonstrated to be critical for the protein self-oligomerization. The dequalinium-binding site was located on the acidic C-terminal region of the protein with an approximate dissociation constant of 5.5 mum. The protein self-oligomerization induced by the compound has resulted in the protofibril formation of alpha-synuclein before it has developed into amyloids. The protofibrils were demonstrated to affect the membrane intactness of liposomes, and they have also been shown to influence cell viability of human neuroblastoma cells. In addition, dequalinium treatment of the alpha-synuclein-overexpressing cells exerted a significant cell death. Therefore, it is pertinent to consider that dequalinium could be used as a molecular probe to assess toxic mechanisms related to the amyloid formation of alpha-synuclein. Ultimately, the compound could be employed to develop therapeutic and preventive strategies toward alpha-synucleinopathies including Parkinson disease.
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Affiliation(s)
- Choong-Hwan Lee
- School of Chemical and Biological Engineering, College of Engineering, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Ku, Seoul 151-744, Korea
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468
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Moore RA, Herzog C, Errett J, Kocisko DA, Arnold KM, Hayes SF, Priola SA. Octapeptide repeat insertions increase the rate of protease-resistant prion protein formation. Protein Sci 2006; 15:609-19. [PMID: 16452616 PMCID: PMC2249780 DOI: 10.1110/ps.051822606] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A central feature of transmissible spongiform encephalopathies (TSE or prion diseases) involves the conversion of a normal, protease-sensitive glycoprotein termed prion protein (PrP-sen) into a pro-tease-resistant form, termed PrP-res. The N terminus of PrP-sen has five copies of a repeating eight amino acid sequence (octapeptide repeat). The presence of one to nine extra copies of this motif is associated with a heritable form of Creutzfeld-Jakob disease (CJD) in humans. An increasing number of octapeptide repeats correlates with earlier CJD onset, suggesting that the rate at which PrP-sen misfolds into PrP-res may be influenced by these mutations. In order to determine if octapeptide repeat insertions influence the rate at which PrP-res is formed, we used a hamster PrP amyloid-forming peptide (residues 23-144) into which two to 10 extra octapeptide repeats were inserted. The spontaneous formation of protease-resistant PrP amyloid from these peptides was more rapid in response to an increased number of octapeptide repeats. Furthermore, experiments using full-length glycosylated hamster PrP-sen demonstrated that PrP-res formation also occurred more rapidly from PrP-sen molecules expressing 10 extra copies of the octapeptide repeat. The rate increase for PrP-res formation did not appear to be due to any influence of the octapeptide repeat region on PrP structure, but rather to more rapid binding between PrP molecules. Our data from both models support the hypothesis that extra octapeptide repeats in PrP increase the rate at which protease resistant PrP is formed which in turn may affect the rate of disease onset in familial forms of CJD.
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Affiliation(s)
- Roger A Moore
- The Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy & Infectious Diseases, National Institutes of Health, 903 S. 4th Street, Hamilton, Montana 59840, USA
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469
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Treiber C. Prion 2005: Between Fundamentals and Society's Needs. SCIENCE OF AGING KNOWLEDGE ENVIRONMENT : SAGE KE 2006; 2006:pe4. [PMID: 16436784 DOI: 10.1126/sageke.2006.4.pe4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Prion diseases for the most part affect individuals older than 60 years of age and share features with other diseases characterized by protein deposits in the brain, such as Alzheimer's disease and Parkinson's disease. The international conference "Prion 2005: Between Fundamentals and Society's Needs," organized by the German Transmissible Spongiform Encephalopathies Research Platform, aimed to integrate and coordinate the research efforts of participants to better achieve prevention, treatment, control, and management of prion diseases, including Creutzfeldt-Jakob disease and fatal familial insomnia in humans. Several main topics were discussed, such as the molecular characteristics of prion strains, the cell biology of cellular and pathogenic forms of the prion proteins, the pathogenesis of the diseases they cause, emerging problems, and promising approaches for therapy and new diagnostic tools. The presentations at the Prion 2005 conference provided new insights in both basic and applied research, which will have broad implications for society's needs.
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Affiliation(s)
- Carina Treiber
- Freie Universitaet Berlin, Thielallee 63, 14195 Berlin, Germany.
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470
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Qin K, O'Donnell M, Zhao RY. Doppel: More rival than double to prion. Neuroscience 2006; 141:1-8. [PMID: 16781817 DOI: 10.1016/j.neuroscience.2006.04.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 04/12/2006] [Accepted: 04/14/2006] [Indexed: 10/24/2022]
Abstract
Conversion of normal cellular prion protein to the diseased form plays an essential role in transmissible spongiform encephalopathies such as mad cow disease and Creutzfeldt-Jakob disease. However, the normal physiological function of prion protein remains elusive. Doppel, a German synonym of double, was initially identified as a prion-like protein due to its structural and biochemical similarities. However, emerging evidence suggests that function of prion protein is more antagonistic to Doppel than synergistic. In this review, basic biochemical and structural similarities of prion protein and Doppel are introduced; evidence demonstrating antagonistic interaction of prion protein with Doppel is presented; and a potential novel activity of Doppel and prion protein in spermatogenesis, which could stimulate new avenues for research, is discussed.
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Affiliation(s)
- K Qin
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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471
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Kunes KC, Cox DL, Singh RRP. One-dimensional model of yeast prion aggregation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:051915. [PMID: 16383653 DOI: 10.1103/physreve.72.051915] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 07/14/2005] [Indexed: 05/05/2023]
Abstract
Mammalian prion proteins (PrP) are of significant public health interest. Yeasts have proteins, which can undergo similar reconformation and aggregation processes to PrP, without posing a threat to the organism. These yeast "prions," such as SUP35, are simpler to experimentally study and model. Recent in vitro studies of the SUP35 protein found long aggregates, pure exponential growth of the misfolded form, and a lag time which depended weakly on the monomer concentration. To explain this data, we have extended a previous model of aggregation kinetics along with a stochastic approach. We assume reconformation only upon aggregation and include aggregate fissioning and an initial nucleation barrier. We find that for sufficiently small nucleation rates or seeding by a small number of preformed nuclei, the models achieve the requisite exponential growth, long aggregates, and a lag time which depends weakly on monomer concentration. The spread in aggregate sizes is well described by the Weibull distribution. All these properties point to the preeminent role of fissioning in the growth of misfolded proteins.
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Affiliation(s)
- K C Kunes
- Department of Physics, University of California, Davis, California 95616, USA
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472
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Abstract
The TSEs (transmissible spongiform encephalopathies) are not only devastating neurological diseases but also provide a biochemical conundrum; how can a disease agent replicate in the apparent absence of genetic material? The prion hypothesis proposes that the TSE agent is a misfolded form of the host glycoprotein PrP (prion protein). However, a number of questions regarding the hypothesis remain to be addressed. We are using gene-targeted PrP transgenics models to investigate these issues. Here we discuss our recent results that examine the importance of PrP's N-glycans to the misfolding of the protein.
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473
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Affiliation(s)
- Glenn Telling
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, USA
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474
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Monitor – biology. Drug Discov Today 2005. [DOI: 10.1016/s1359-6446(05)03545-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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