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Simmons SM, Bartz JC. Strain-Specific Targeting and Destruction of Cells by Prions. BIOLOGY 2024; 13:57. [PMID: 38275733 PMCID: PMC10813089 DOI: 10.3390/biology13010057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/11/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024]
Abstract
Prion diseases are caused by the disease-specific self-templating infectious conformation of the host-encoded prion protein, PrPSc. Prion strains are operationally defined as a heritable phenotype of disease under controlled conditions. One of the hallmark phenotypes of prion strain diversity is tropism within and between tissues. A defining feature of prion strains is the regional distribution of PrPSc in the CNS. Additionally, in both natural and experimental prion disease, stark differences in the tropism of prions in secondary lymphoreticular system tissues occur. The mechanism underlying prion tropism is unknown; however, several possible hypotheses have been proposed. Clinical target areas are prion strain-specific populations of neurons within the CNS that are susceptible to neurodegeneration following the replication of prions past a toxic threshold. Alternatively, the switch from a replicative to toxic form of PrPSc may drive prion tropism. The normal form of the prion protein, PrPC, is required for prion formation. More recent evidence suggests that it can mediate prion and prion-like disease neurodegeneration. In vitro systems for prion formation have indicated that cellular cofactors contribute to prion formation. Since these cofactors can be strain specific, this has led to the hypothesis that the distribution of prion formation cofactors can influence prion tropism. Overall, there is evidence to support several mechanisms of prion strain tropism; however, a unified theory has yet to emerge.
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Affiliation(s)
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE 68178, USA;
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2
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Foliaki ST, Wood A, Williams K, Smith A, Walters RO, Baune C, Groveman BR, Haigh CL. Temporary alteration of neuronal network communication is a protective response to redox imbalance that requires GPI-anchored prion protein. Redox Biol 2023; 63:102733. [PMID: 37172395 DOI: 10.1016/j.redox.2023.102733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/25/2023] [Accepted: 05/05/2023] [Indexed: 05/15/2023] Open
Abstract
Cellular prion protein (PrPC) protects neurons against oxidative stress damage. This role is lost upon its misfolding into insoluble prions in prion diseases, and correlated with cytoskeletal breakdown and neurophysiological deficits. Here we used mouse neuronal models to assess how PrPC protects the neuronal cytoskeleton, and its role in network communication, from oxidative stress damage. Oxidative stress was induced extrinsically by potassium superoxide (KO2) or intrinsically by Mito-Paraquat (MtPQ), targeting the mitochondria. In mouse neural lineage cells, KO2 was damaging to the cytoskeleton, with cells lacking PrPC (PrP-/-) damaged more than wild-type (WT) cells. In hippocampal slices, KO2 acutely inhibited neuronal communication in WT controls without damaging the cytoskeleton. This inhibition was not observed in PrP-/- slices. Neuronal communication and the cytoskeleton of PrP-/- slices became progressively disrupted and degenerated post-recovery, whereas the dysfunction in WT slices recovered in 5 days. This suggests that the acute inhibition of neuronal activity in WT slices in response to KO2 was a neuroprotective role of PrPC, which PrP-/- slices lacked. Heterozygous expression of PrPC was sufficient for this neuroprotection. Further, hippocampal slices from mice expressing PrPC without its GPI anchor (PrPGPI-/-) displayed acute inhibition of neuronal activity by KO2. However, they failed to restore normal activity and cytoskeletal formation post-recovery. This suggests that PrPC facilitates the depressive response to KO2 and its GPI anchoring is required to restore KO2-induced damages. Immuno spin-trapping showed increased radicals formed on the filamentous actin of PrP-/- and PrPGPI-/- slices, but not WT and PrP+/- slices, post-recovery suggesting ongoing dysregulation of redox balance in the slices lacking GPI-anchored PrPC. The MtPQ treatment of hippocampal slices temporarily inhibited neuronal communication independent of PrPC expression. Overall, GPI-anchored PrPC alters synapses and neurotransmission to protect and repair the neuronal cytoskeleton, and neuronal communication, from extrinsically induced oxidative stress damages.
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Affiliation(s)
- Simote T Foliaki
- Laboratory of Persistent Viral Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT, 59840, USA.
| | - Aleksandar Wood
- Laboratory of Persistent Viral Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Katie Williams
- Laboratory of Persistent Viral Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Anna Smith
- Laboratory of Persistent Viral Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Ryan O Walters
- Laboratory of Persistent Viral Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Chase Baune
- Laboratory of Persistent Viral Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Bradley R Groveman
- Laboratory of Persistent Viral Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Cathryn L Haigh
- Laboratory of Persistent Viral Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, MT, 59840, USA.
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3
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Mercer RCC, Harris DA. Mechanisms of prion-induced toxicity. Cell Tissue Res 2022; 392:81-96. [PMID: 36070155 DOI: 10.1007/s00441-022-03683-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/30/2022] [Indexed: 11/02/2022]
Abstract
Prion diseases are devastating neurodegenerative diseases caused by the structural conversion of the normally benign prion protein (PrPC) to an infectious, disease-associated, conformer, PrPSc. After decades of intense research, much is known about the self-templated prion conversion process, a phenomenon which is now understood to be operative in other more common neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. In this review, we provide the current state of knowledge concerning a relatively poorly understood aspect of prion diseases: mechanisms of neurotoxicity. We provide an overview of proposed functions of PrPC and its interactions with other extracellular proteins in the central nervous system, in vivo and in vitro models used to delineate signaling events downstream of prion propagation, the application of omics technologies, and the emerging appreciation of the role played by non-neuronal cell types in pathogenesis.
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Affiliation(s)
- Robert C C Mercer
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA.
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4
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Mays CE, Trinh THT, Telling G, Kang HE, Ryou C. Endoproteolysis of cellular prion protein by plasmin hinders propagation of prions. Front Mol Neurosci 2022; 15:990136. [PMID: 36117913 PMCID: PMC9478470 DOI: 10.3389/fnmol.2022.990136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/15/2022] [Indexed: 01/21/2023] Open
Abstract
Many questions surround the underlying mechanism for the differential metabolic processing observed for the prion protein (PrP) in healthy and prion-infected mammals. Foremost, the physiological α-cleavage of PrP interrupts a region critical for both toxicity and conversion of cellular PrP (PrP C ) into its misfolded pathogenic isoform (PrP Sc ) by generating a glycosylphosphatidylinositol (GPI)-anchored C1 fragment. During prion diseases, alternative β-cleavage of PrP becomes prominent, producing a GPI-anchored C2 fragment with this particular region intact. It remains unexplored whether physical up-regulation of α-cleavage can inhibit disease progression. Furthermore, several pieces of evidence indicate that a disintegrin and metalloproteinase (ADAM) 10 and ADAM17 play a much smaller role in the α-cleavage of PrP C than originally believed, thus presenting the need to identify the primary protease(s) responsible. For this purpose, we characterized the ability of plasmin to perform PrP α-cleavage. Then, we conducted functional assays using protein misfolding cyclic amplification (PMCA) and prion-infected cell lines to clarify the role of plasmin-mediated α-cleavage during prion propagation. Here, we demonstrated an inhibitory role of plasmin for PrP Sc formation through PrP α-cleavage that increased C1 fragments resulting in reduced prion conversion compared with non-treated PMCA and cell cultures. The reduction of prion infectious titer in the bioassay of plasmin-treated PMCA material also supported the inhibitory role of plasmin on PrP Sc replication. Our results suggest that plasmin-mediated endoproteolytic cleavage of PrP may be an important event to prevent prion propagation.
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Affiliation(s)
- Charles E. Mays
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Trang H. T. Trinh
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, South Korea,Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, South Korea
| | - Glenn Telling
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States,Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States,Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Hae-Eun Kang
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States,Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States,Reference Laboratory for Chronic Wasting Disease (CWD), Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon, South Korea,Hae-Eun Kang,
| | - Chongsuk Ryou
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States,Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, South Korea,Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, South Korea,Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States,*Correspondence: Chongsuk Ryou,
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Kim C, Haldiman T, Kang SG, Hromadkova L, Han ZZ, Chen W, Lissemore F, Lerner A, de Silva R, Cohen ML, Westaway D, Safar JG. Distinct populations of highly potent TAU seed conformers in rapidly progressing Alzheimer's disease. Sci Transl Med 2022; 14:eabg0253. [PMID: 34985969 DOI: 10.1126/scitranslmed.abg0253] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Chae Kim
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Tracy Haldiman
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Sang-Gyun Kang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton T6G 2M8, Canada
| | - Lenka Hromadkova
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Zhuang Zhuang Han
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton T6G 2M8, Canada
| | - Wei Chen
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Frances Lissemore
- Department of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Alan Lerner
- Department of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Rohan de Silva
- Reta Lila Weston Institute of Neurological Studies and Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 1PJ, UK
| | - Mark L Cohen
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton T6G 2M8, Canada
| | - Jiri G Safar
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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The cellular prion protein interacts with and promotes the activity of Na,K-ATPases. PLoS One 2021; 16:e0258682. [PMID: 34847154 PMCID: PMC8631662 DOI: 10.1371/journal.pone.0258682] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 10/02/2021] [Indexed: 12/23/2022] Open
Abstract
The prion protein (PrP) is best known for its ability to cause fatal neurodegenerative diseases in humans and animals. Here, we revisited its molecular environment in the brain using a well-developed affinity-capture mass spectrometry workflow that offers robust relative quantitation. The analysis confirmed many previously reported interactions. It also pointed toward a profound enrichment of Na,K-ATPases (NKAs) in proximity to cellular PrP (PrPC). Follow-on work validated the interaction, demonstrated partial co-localization of the ATP1A1 and PrPC, and revealed that cells exposed to cardiac glycoside (CG) inhibitors of NKAs exhibit correlated changes to the steady-state levels of both proteins. Moreover, the presence of PrPC was observed to promote the ion uptake activity of NKAs in a human co-culture paradigm of differentiated neurons and glia cells, and in mouse neuroblastoma cells. Consistent with this finding, changes in the expression of 5’-nucleotidase that manifest in wild-type cells in response to CG exposure can also be observed in untreated PrPC-deficient cells. Finally, the endoproteolytic cleavage of the glial fibrillary acidic protein, a hallmark of late-stage prion disease, can also be induced by CGs, raising the prospect that a loss of NKA activity may contribute to the pathobiology of prion diseases.
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7
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Thompson TB, Meisl G, Knowles TPJ, Goriely A. The role of clearance mechanisms in the kinetics of pathological protein aggregation involved in neurodegenerative diseases. J Chem Phys 2021; 154:125101. [PMID: 33810689 DOI: 10.1063/5.0031650] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The deposition of pathological protein aggregates in the brain plays a central role in cognitive decline and structural damage associated with neurodegenerative diseases. In Alzheimer's disease, the formation of amyloid-β plaques and neurofibrillary tangles of the tau protein is associated with the appearance of symptoms and pathology. Detailed models for the specific mechanisms of aggregate formation, such as nucleation and elongation, exist for aggregation in vitro where the total protein mass is conserved. However, in vivo, an additional class of mechanisms that clear pathological species is present and is believed to play an essential role in limiting the formation of aggregates and preventing or delaying the emergence of disease. A key unanswered question in the field of neuro-degeneration is how these clearance mechanisms can be modeled and how alterations in the processes of clearance or aggregation affect the stability of the system toward aggregation. Here, we generalize classical models of protein aggregation to take into account both production of monomers and the clearance of protein aggregates. We show that, depending on the specifics of the clearance process, a critical clearance value emerges above which accumulation of aggregates does not take place. Our results show that a sudden switch from a healthy to a disease state can be caused by small variations in the efficiency of the clearance process and provide a mathematical framework to explore the detailed effects of different mechanisms of clearance on the accumulation of aggregates.
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Affiliation(s)
- T B Thompson
- Mathematical Institute, University of Oxford, Oxford, United Kingdom
| | - G Meisl
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - T P J Knowles
- Department of Chemistry and Department of Physics, University of Cambridge, Cambridge, United Kingdom
| | - A Goriely
- Mathematical Institute, University of Oxford, Oxford, United Kingdom
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8
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Meisl G, Kurt T, Condado-Morales I, Bett C, Sorce S, Nuvolone M, Michaels TCT, Heinzer D, Avar M, Cohen SIA, Hornemann S, Aguzzi A, Dobson CM, Sigurdson CJ, Knowles TPJ. Scaling analysis reveals the mechanism and rates of prion replication in vivo. Nat Struct Mol Biol 2021; 28:365-372. [PMID: 33767451 PMCID: PMC8922999 DOI: 10.1038/s41594-021-00565-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 01/26/2021] [Indexed: 01/03/2023]
Abstract
Prions consist of pathological aggregates of cellular prion protein and have the ability to replicate, causing neurodegenerative diseases, a phenomenon mirrored in many other diseases connected to protein aggregation, including Alzheimer's and Parkinson's diseases. However, despite their key importance in disease, the individual processes governing this formation of pathogenic aggregates, as well as their rates, have remained challenging to elucidate in vivo. Here we bring together a mathematical framework with kinetics of the accumulation of prions in mice and microfluidic measurements of aggregate size to dissect the overall aggregation reaction into its constituent processes and quantify the reaction rates in mice. Taken together, the data show that multiplication of prions in vivo is slower than in in vitro experiments, but efficient when compared with other amyloid systems, and displays scaling behavior characteristic of aggregate fragmentation. These results provide a framework for the determination of the mechanisms of disease-associated aggregation processes within living organisms.
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Affiliation(s)
- Georg Meisl
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Timothy Kurt
- Department of Pathology, UC San Diego, San Diego, CA, USA
| | - Itzel Condado-Morales
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - Cyrus Bett
- Department of Pathology, UC San Diego, San Diego, CA, USA
| | - Silvia Sorce
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - Mario Nuvolone
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
- Amyloidosis Research and Treatment Center, Foundation IRCCS Policlinico San Matteo, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Thomas C T Michaels
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Daniel Heinzer
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - Merve Avar
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - Samuel I A Cohen
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Wren Therapeutics, Cambridge, UK
| | - Simone Hornemann
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - Adriano Aguzzi
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - Christopher M Dobson
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
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Eskandari-Sedighi G, Cortez LM, Yang J, Daude N, Shmeit K, Sim V, Westaway D. Quaternary Structure Changes for PrP Sc Predate PrP C Downregulation and Neuronal Death During Progression of Experimental Scrapie Disease. Mol Neurobiol 2021; 58:375-390. [PMID: 32959170 PMCID: PMC7695655 DOI: 10.1007/s12035-020-02112-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 09/01/2020] [Indexed: 01/20/2023]
Abstract
Prion diseases are fatal neurodegenerative diseases in mammals with the unique characteristics of misfolding and aggregation of the cellular prion protein (PrPC) to the scrapie prion (PrPSc). Although neuroinflammation and neuronal loss feature within the disease process, the details of PrPC/PrPSc molecular transition to generate different aggregated species, and the correlation between each species and sequence of cellular events in disease pathogenesis are not fully understood. In this study, using mice inoculated with the RML isolate of mouse-adapted scrapie as a model, we applied asymmetric flow field-flow fractionation to monitor PrPC and PrPSc particle sizes and we also measured seeding activity and resistance to proteases. For cellular analysis in brain tissue, we measured inflammatory markers and synaptic damage, and used the isotropic fractionator to measure neuronal loss; these techniques were applied at different timepoints in a cross-sectional study of disease progression. Our analyses align with previous reports defining significant decreases in PrPC levels at pre-clinical stages of the disease and demonstrate that these decreases become significant before neuronal loss. We also identified the earliest PrPSc assemblies at a timepoint equivalent to 40% elapsed time for the disease incubation period; we propose that these assemblies, mostly composed of proteinase K (PK)-sensitive species, play an important role in triggering disease pathogenesis. Lastly, we show that the PK-resistant assemblies of PrPSc that appear at timepoints close to the terminal stage have similar biophysical characteristics, and hence that preparative use of PK-digestion selects for this specific subpopulation. In sum, our data argue that qualitative, as well as quantitative, changes in PrP conformers occur at the midpoint of subclinical phase; these changes affect quaternary structure and may occur at the threshold where adaptive responses become inadequate to deal with pathogenic processes.
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Affiliation(s)
- Ghazaleh Eskandari-Sedighi
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
| | - Leonardo M Cortez
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, AB, Canada
| | - Jing Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
| | - Nathalie Daude
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
| | - Klinton Shmeit
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
| | - Valerie Sim
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, AB, Canada
| | - David Westaway
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada.
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Fu ZL, Mercier P, Eskandari-Sedighi G, Yang J, Westaway D, Sykes BD. Metabolomic study of disease progression in scrapie prion infected mice; validation of a novel method for brain metabolite extraction. Metabolomics 2020; 16:72. [PMID: 32533504 DOI: 10.1007/s11306-020-01690-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/28/2020] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Prion disease is a form of neurodegenerative disease caused by the misfolding and aggregation of cellular prion protein (PrPC). The neurotoxicity of the misfolded form of prion protein, PrPSc still remains understudied. Here we try to investigate this issue using a metabolomics approach. OBJECTIVES The intention was to identify and quantify the small-in-size and water-soluble metabolites extracted from mice brains infected with the Rocky Mountain Laboratory isolate of mouse-adapted scrapie prions (RML) and track changes in these metabolites during disease evolution. METHODS A total of 73 mice were inoculated with RML prions or normal brain homogenate control; brains were harvested at 30, 60, 90, 120 and 150 days post-inoculation (dpi). We devised a high-efficiency metabolite extraction method and used nuclear magnetic resonance spectroscopy to identify and quantify 50 metabolites in the brain extracts. Data were analyzed using multivariate approach. RESULTS Brain metabolome profiles of RML infected animals displayed continuous changes throughout the course of disease. Among the analyzed metabolites, the most noteworthy changes included increases in myo-inositol and glutamine as well as decreases in 4-aminobutyrate, acetate, aspartate and taurine. CONCLUSION We report a novel metabolite extraction method for lipid-rich tissue. As all the major metabolites are identifiable and quantifiable by magnetic resonance spectroscopy, this study suggests that tracking of neurochemical profiles could be effective in monitoring the progression of neurodegenerative diseases and useful for assessing the efficacy of candidate therapeutics.
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Affiliation(s)
- Ze-Lin Fu
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Pascal Mercier
- National High Field Nuclear Magnetic Resonance Centre (NANUC), Edmonton, AB, Canada
| | - Ghazaleh Eskandari-Sedighi
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Jing Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - David Westaway
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Brian D Sykes
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
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PrPSc Oligomerization Appears Dynamic, Quickly Engendering Inherent M1000 Acute Synaptotoxicity. Biophys J 2020; 119:128-141. [PMID: 32562618 DOI: 10.1016/j.bpj.2020.04.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/07/2020] [Accepted: 04/24/2020] [Indexed: 11/23/2022] Open
Abstract
Prion diseases are neurodegenerative disorders pathogenically linked to cellular prion protein (PrPC) misfolding into abnormal conformers (PrPSc), with PrPSc underpinning both transmission and synaptotoxicity. Although the biophysical features of PrPSc required to induce acute synaptic dysfunction remain incompletely defined, we recently reported that acutely synaptotoxic PrPSc appeared to be oligomeric. We herein provide further insights into the kinetic and requisite biophysical characteristics of acutely synaptotoxic ex vivo PrPSc derived from the brains of mice dying from M1000 prion disease. Pooled fractions of M1000 PrPSc located within the molecular weight range approximating monomeric PrP (mM1000) generated through size exclusion chromatography were found to harbor acute synaptotoxicity equivalent to preformed oligomeric fractions (oM1000). Subsequent investigation showed mM1000 corresponded to PrPSc rapidly concatenating in physiological buffer to exist as predominantly, closely associated, small oligomers. The oligomerization of PrP in mM1000 could be substantially mitigated by treatment with the antiaggregation compound epigallocatechin gallate, thereby maintaining the PrPSc as primarily nonoligomeric with completely abrogated acute synaptotoxicity; moreover, despite epigallocatechin gallate treatment, pooled oM1000 remained oligomeric and acutely synaptotoxic. A similar tendency to rapid formation of oligomers was observed for PrPC when monomeric fractions derived from size exclusion chromatography of normal brain homogenates (mNBH) were pooled, but neither mNBH nor preformed higher-order NBH complexes (oNBH) were acutely synaptotoxic. Oligomers formed from mNBH could be reduced to mainly monomers (<100 kDa) after enzymatic digestion of nucleic acids, whereas higher-order PrP assemblies derived from pooled mM1000, oM1000, and oNBH resisted such treatment. Collectively, these findings support that oligomerization of PrPSc into small multimeric assemblies appears to be a critical biophysical feature for engendering inherent acute synaptotoxicity, with preformed oligomers found in oM1000 appearing to be stable, tightly self-associated ensembles that coexist in dynamic equilibrium with mM1000, with the latter appearing capable of rapid aggregation, albeit initially forming smaller, weakly self-associated, acutely synaptotoxic oligomers.
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12
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Duque Velásquez C, Kim C, Haldiman T, Kim C, Herbst A, Aiken J, Safar JG, McKenzie D. Chronic wasting disease (CWD) prion strains evolve via adaptive diversification of conformers in hosts expressing prion protein polymorphisms. J Biol Chem 2020; 295:4985-5001. [PMID: 32111742 PMCID: PMC7152757 DOI: 10.1074/jbc.ra120.012546] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/22/2020] [Indexed: 11/06/2022] Open
Abstract
Chronic wasting disease (CWD) is caused by an unknown spectrum of prions and has become enzootic in populations of cervid species that express cellular prion protein (PrPC) molecules varying in amino acid composition. These PrPC polymorphisms can affect prion transmission, disease progression, neuropathology, and emergence of new prion strains, but the mechanistic steps in prion evolution are not understood. Here, using conformation-dependent immunoassay, conformation stability assay, and protein-misfolding cyclic amplification, we monitored the conformational and phenotypic characteristics of CWD prions passaged through deer and transgenic mice expressing different cervid PrPC polymorphisms. We observed that transmission through hosts with distinct PrPC sequences diversifies the PrPCWD conformations and causes a shift toward oligomers with defined structural organization, replication rate, and host range. When passaged in host environments that restrict prion replication, distinct co-existing PrPCWD conformers underwent competitive selection, stabilizing a new prion strain. Nonadaptive conformers exhibited unstable replication and accumulated only to low levels. These results suggest a continuously evolving diversity of CWD conformers and imply a critical interplay between CWD prion plasticity and PrPC polymorphisms during prion strain evolution.
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Affiliation(s)
- Camilo Duque Velásquez
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
| | - Chae Kim
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Tracy Haldiman
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Chiye Kim
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
| | - Allen Herbst
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Judd Aiken
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Jiri G Safar
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
- Department of Neurology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Debbie McKenzie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
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13
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Lathe R, Darlix JL. Prion protein PrP nucleic acid binding and mobilization implicates retroelements as the replicative component of transmissible spongiform encephalopathy. Arch Virol 2020; 165:535-556. [PMID: 32025859 PMCID: PMC7024060 DOI: 10.1007/s00705-020-04529-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/13/2019] [Indexed: 12/21/2022]
Abstract
The existence of more than 30 strains of transmissible spongiform encephalopathy (TSE) and the paucity of infectivity of purified PrPSc, as well as considerations of PrP structure, are inconsistent with the protein-only (prion) theory of TSE. Nucleic acid is a strong contender as a second component. We juxtapose two key findings: (i) PrP is a nucleic-acid-binding antimicrobial protein that is similar to retroviral Gag proteins in its ability to trigger reverse transcription. (ii) Retroelement mobilization is widely seen in TSE disease. Given further evidence that PrP also mediates nucleic acid transport into and out of the cell, a strong case is to be made that a second element – retroelement nucleic acid – bound to PrP constitutes the second component necessary to explain the multiple strains of TSE.
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Affiliation(s)
- Richard Lathe
- Division of Infection Medicine, University of Edinburgh School of Medicine, Edinburgh, UK. .,Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, Moscow, Moscow Region, Russia.
| | - Jean-Luc Darlix
- Faculté de Pharmacie, Centre Nationale de la Recherche Scientifique (CNRS) Laboratory of Bioimaging and Pathologies (Unité Mixte de Recherche 7021), Université de Strasbourg, Illkirch, France.
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14
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Salvesen Ø, Espenes A, Reiten MR, Vuong TT, Malachin G, Tran L, Andréoletti O, Olsaker I, Benestad SL, Tranulis MA, Ersdal C. Goats naturally devoid of PrP C are resistant to scrapie. Vet Res 2020; 51:1. [PMID: 31924264 PMCID: PMC6954626 DOI: 10.1186/s13567-019-0731-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/17/2019] [Indexed: 12/14/2022] Open
Abstract
Prion diseases are progressive and fatal, neurodegenerative disorders described in humans and animals. According to the "protein-only" hypothesis, the normal host-encoded prion protein (PrPC) is converted into a pathological and infectious form (PrPSc) in these diseases. Transgenic knockout models have shown that PrPC is a prerequisite for the development of prion disease. In Norwegian dairy goats, a mutation (Ter) in the prion protein gene (PRNP) effectively blocks PrPC synthesis. We inoculated 12 goats (4 PRNP+/+, 4 PRNP+/Ter, and 4 PRNPTer/Ter) intracerebrally with goat scrapie prions. The mean incubation time until clinical signs of prion disease was 601 days post-inoculation (dpi) in PRNP+/+ goats and 773 dpi in PRNP+/Ter goats. PrPSc and vacuolation were similarly distributed in the central nervous system (CNS) of both groups and observed in all brain regions and segments of the spinal cord. Generally, accumulation of PrPSc was limited in peripheral organs, but all PRNP+/+ goats and 1 of 4 PRNP+/Ter goats were positive in head lymph nodes. The four PRNPTer/Ter goats remained healthy, without clinical signs of prion disease, and were euthanized 1260 dpi. As expected, no accumulation of PrPSc was observed in the CNS or peripheral tissues of this group, as assessed by immunohistochemistry, enzyme immunoassay, and real-time quaking-induced conversion. Our study shows for the first time that animals devoid of PrPC due to a natural mutation do not propagate prions and are resistant to scrapie. Clinical onset of disease is delayed in heterozygous goats expressing about 50% of PrPC levels.
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Affiliation(s)
- Øyvind Salvesen
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Sandnes, Norway
| | - Arild Espenes
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Malin R. Reiten
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
- Norwegian Veterinary Institute, Oslo, Norway
| | | | - Giulia Malachin
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Linh Tran
- Norwegian Veterinary Institute, Oslo, Norway
| | | | - Ingrid Olsaker
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Michael A. Tranulis
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Cecilie Ersdal
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Sandnes, Norway
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15
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Mays CE, Armijo E, Morales R, Kramm C, Flores A, Tiwari A, Bian J, Telling GC, Pandita TK, Hunt CR, Soto C. Prion disease is accelerated in mice lacking stress-induced heat shock protein 70 (HSP70). J Biol Chem 2019; 294:13619-13628. [PMID: 31320473 DOI: 10.1074/jbc.ra118.006186] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 06/28/2019] [Indexed: 01/09/2023] Open
Abstract
Prion diseases are a group of incurable neurodegenerative disorders that affect humans and animals via infection with proteinaceous particles called prions. Prions are composed of PrPSc, a misfolded version of the cellular prion protein (PrPC). During disease progression, PrPSc replicates by interacting with PrPC and inducing its conversion to PrPSc As PrPSc accumulates, cellular stress mechanisms are activated to maintain cellular proteostasis, including increased protein chaperone levels. However, the exact roles of several of these chaperones remain unclear. Here, using various methodologies to monitor prion replication (i.e. protein misfolding cyclic amplification and cellular and animal infectivity bioassays), we studied the potential role of the molecular chaperone heat shock protein 70 (HSP70) in prion replication in vitro and in vivo Our results indicated that pharmacological induction of the heat shock response in cells chronically infected with prions significantly decreased PrPSc accumulation. We also found that HSP70 alters prion replication in vitro More importantly, prion infection of mice lacking the genes encoding stress-induced HSP70 exhibited accelerated prion disease progression compared with WT mice. In parallel with HSP70 being known to respond to endogenous and exogenous stressors such as heat, infection, toxicants, and ischemia, our results indicate that HSP70 may also play an important role in suppressing or delaying prion disease progression, opening opportunities for therapeutic intervention.
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Affiliation(s)
- Charles E Mays
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas McGovern Medical School, Houston, Texas 77030
| | - Enrique Armijo
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas McGovern Medical School, Houston, Texas 77030.,Facultad de Medicina, Universidad de los Andes, Av. San Carlos de Apoquindo, 2200 Las Condes, Santiago, Chile
| | - Rodrigo Morales
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas McGovern Medical School, Houston, Texas 77030
| | - Carlos Kramm
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas McGovern Medical School, Houston, Texas 77030.,Facultad de Medicina, Universidad de los Andes, Av. San Carlos de Apoquindo, 2200 Las Condes, Santiago, Chile
| | - Andrea Flores
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas McGovern Medical School, Houston, Texas 77030
| | - Anjana Tiwari
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, Texas 77030
| | - Jifeng Bian
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Glenn C Telling
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Tej K Pandita
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, Texas 77030
| | - Clayton R Hunt
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, Texas 77030
| | - Claudio Soto
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas McGovern Medical School, Houston, Texas 77030 .,Facultad de Medicina, Universidad de los Andes, Av. San Carlos de Apoquindo, 2200 Las Condes, Santiago, Chile
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16
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Nonno R, Notari S, Di Bari MA, Cali I, Pirisinu L, d'Agostino C, Cracco L, Kofskey D, Vanni I, Lavrich J, Parchi P, Agrimi U, Gambetti P. Variable Protease-Sensitive Prionopathy Transmission to Bank Voles. Emerg Infect Dis 2019; 25:73-81. [PMID: 30561322 PMCID: PMC6302590 DOI: 10.3201/eid2501.180807] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Variably protease-sensitive prionopathy (VPSPr), a recently described human sporadic prion disease, features a protease-resistant, disease-related prion protein (resPrPD) displaying 5 fragments reminiscent of Gerstmann-Sträussler-Scheinker disease. Experimental VPSPr transmission to human PrP-expressing transgenic mice, although replication of the VPSPr resPrPD profile succeeded, has been incomplete because of second passage failure. We bioassayed VPSPr in bank voles, which are susceptible to human prion strains. Transmission was complete; first-passage attack rates were 5%-35%, and second-passage rates reached 100% and survival times were 50% shorter. We observed 3 distinct phenotypes and resPrPD profiles; 2 imitated sporadic Creutzfeldt-Jakob disease resPrPD, and 1 resembled Gerstmann-Sträussler-Scheinker disease resPrPD. The first 2 phenotypes may be related to the presence of minor PrPD components in VPSPr. Full VPSPr transmission confirms permissiveness of bank voles to human prions and suggests that bank vole PrP may efficiently reveal an underrepresented native strain but does not replicate the complex VPSPr PrPD profile.
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17
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Proteasomal Inhibition Redirects the PrP-Like Shadoo Protein to the Nucleus. Mol Neurobiol 2019; 56:7888-7904. [PMID: 31129810 PMCID: PMC6815274 DOI: 10.1007/s12035-019-1623-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/24/2019] [Indexed: 01/08/2023]
Abstract
The Shadoo protein (Sho) exhibits homology to the hydrophobic region of the cellular isoform of prion protein (PrPC). As prion-infected brains gradually accumulate infectivity-associated isoforms of prion protein (PrPSc), levels of mature endogenous Sho become reduced. To study the regulatory effect of the proteostatic network on Sho expression, we investigated the action of lactacystin, MG132, NH4Cl, and 3-methyladenine (3-MA) in two cell culture models. In primary mixed neuronal and glial cell cultures (MNGCs) from transgenic mice expressing wild-type Sho from the PrP gene promoter (Tg.Sprn mice), lactacystin- and MG132-mediated inhibition of proteasomal activity shifted the repertoire of Sho species towards unglycosylated forms appearing in the nuclei; conversely, the autophagic modulators NH4Cl and 3-MA did not affect Sho or PrPC glycosylation patterns. Mouse N2a neuroblastoma cells expressing Sho under control of a housekeeping gene promoter treated with MG132 or lactacystin also showed increased nuclear localization of unglycosylated Sho. As two proteasomal inhibitors tested in two cell paradigms caused redirection of Sho to nuclei at the expense of processing through the secretory pathway, our findings define a balanced shift in subcellular localization that thereby differs from the decreases in net Sho species seen in prion-infected brains. Our data are indicative of a physiological pathway to access Sho functions in the nucleus under conditions of impaired proteasomal activity. We also infer that these conditions would comprise a context wherein Sho’s N-terminal nucleic acid–binding RGG repeat region is brought into play.
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18
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Foliaki ST, Lewis V, Islam AMT, Ellett LJ, Senesi M, Finkelstein DI, Roberts B, Lawson VA, Adlard PA, Collins SJ. Early existence and biochemical evolution characterise acutely synaptotoxic PrPSc. PLoS Pathog 2019; 15:e1007712. [PMID: 30970042 PMCID: PMC6490942 DOI: 10.1371/journal.ppat.1007712] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 04/30/2019] [Accepted: 03/18/2019] [Indexed: 11/19/2022] Open
Abstract
Although considerable evidence supports that misfolded prion protein (PrPSc) is the principal component of “prions”, underpinning both transmissibility and neurotoxicity, clear consensus around a number of fundamental aspects of pathogenesis has not been achieved, including the time of appearance of neurotoxic species during disease evolution. Utilizing a recently reported electrophysiology paradigm, we assessed the acute synaptotoxicity of ex vivo PrPSc prepared as crude homogenates from brains of M1000 infected wild-type mice (cM1000) harvested at time-points representing 30%, 50%, 70% and 100% of the terminal stage of disease (TSD). Acute synaptotoxicity was assessed by measuring the capacity of cM1000 to impair hippocampal CA1 region long-term potentiation (LTP) and post-tetanic potentiation (PTP) in explant slices. Of particular note, cM1000 from 30% of the TSD was able to cause significant impairment of LTP and PTP, with the induced failure of LTP increasing over subsequent time-points while the capacity of cM1000 to induce PTP failure appeared maximal even at this early stage of disease progression. Evidence that the synaptotoxicity directly related to PrP species was demonstrated by the significant rescue of LTP dysfunction at each time-point through immuno-depletion of >50% of total PrP species from cM1000 preparations. Moreover, similar to our previous observations at the terminal stage of M1000 prion disease, size fractionation chromatography revealed that capacity for acute synpatotoxicity correlated with predominance of oligomeric PrP species in infected brains across all time points, with the profile appearing maximised by 50% of the TSD. Using enhanced sensitivity western blotting, modestly proteinase K (PK)-resistant PrPSc was detectable at very low levels in cM1000 at 30% of the TSD, becoming robustly detectable by 70% of the TSD at which time substantial levels of highly PK-resistant PrPSc was also evident. Further illustrating the biochemical evolution of acutely synaptotoxic species the synaptotoxicity of cM1000 from 30%, 50% and 70% of the TSD, but not at 100% TSD, was abolished by digestion of immuno-captured PrP species with mild PK treatment (5μg/ml for an hour at 37°C), demonstrating that the predominant synaptotoxic PrPSc species up to and including 70% of the TSD were proteinase-sensitive. Overall, these findings in combination with our previous assessments of transmitting prions support that synaptotoxic and infectious M1000 PrPSc species co-exist from at least 30% of the TSD, simultaneously increasing thereafter, albeit with eventual plateauing of transmitting conformers. Although evidence clearly supports that misfolded prion protein (PrPSc) is the principal component of “prions”, underpinning both transmissibility and neurotoxicity, consensus is lacking around the time of appearance and biochemical profile of neurotoxic species during disease evolution. Employing an electrophysiology model, measuring the capacity of brain homogenates derived from across the disease time-course to impair CA1 region long-term potentiation (LTP) and post-tetanic potentiation (PTP) in hippocampal slices, we observed that synaptotoxic species were present from 30% of the terminal stage of disease (TSD). Evidence that synaptotoxicity directly related to PrP species was demonstrated by significant rescue of LTP dysfunction at each time-point through immuno-depleting >~50% of total PrP species from cM1000 preparations. Moreover, size fractionation chromatography revealed that acute synpatotoxicity correlated with predominance of oligomeric PrP species in infected brains across all time points, while additional characterisation of cM1000 demonstrated that the predominant synaptotoxic PrPSc species up to and including 70% of the TSD were quite proteinase-sensitive. These findings in combination with our previous assessments of transmitting prions support that synaptotoxic and infectious M1000 PrPSc species co-exist from at least 30% of the TSD, simultaneously increasing thereafter, with biochemical transformation of synaptotoxic conformers continuing until late in disease.
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Affiliation(s)
- Simote Totauhelotu Foliaki
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Victoria, Australia
| | - Victoria Lewis
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Victoria, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | | | - Laura Jane Ellett
- Department of Pathology The University of Melbourne, Parkville, Victoria, Australia
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria, Australia
| | - Matteo Senesi
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Victoria, Australia
| | | | - Blaine Roberts
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Victoria A. Lawson
- Department of Pathology The University of Melbourne, Parkville, Victoria, Australia
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria, Australia
| | - Paul Anthony Adlard
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Steven John Collins
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Victoria, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- * E-mail:
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19
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Abstract
Prion diseases are rapidly progressive, incurable neurodegenerative disorders caused by misfolded, aggregated proteins known as prions, which are uniquely infectious. Remarkably, these infectious proteins have been responsible for widespread disease epidemics, including kuru in humans, bovine spongiform encephalopathy in cattle, and chronic wasting disease in cervids, the latter of which has spread across North America and recently appeared in Norway and Finland. The hallmark histopathological features include widespread spongiform encephalopathy, neuronal loss, gliosis, and deposits of variably sized aggregated prion protein, ranging from small, soluble oligomers to long, thin, unbranched fibrils, depending on the disease. Here, we explore recent advances in prion disease research, from the function of the cellular prion protein to the dysfunction triggering neurotoxicity, as well as mechanisms underlying prion spread between cells. We also highlight key findings that have revealed new therapeutic targets and consider unanswered questions for future research.
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Affiliation(s)
- Christina J Sigurdson
- Departments of Pathology and Medicine, UC San Diego School of Medicine, University of California, San Diego, La Jolla, California 92093, USA;
| | - Jason C Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska 68178, USA
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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20
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Lemarre P, Pujo-Menjouet L, Sindi SS. Generalizing a mathematical model of prion aggregation allows strain coexistence and co-stability by including a novel misfolded species. J Math Biol 2018; 78:465-495. [PMID: 30116882 PMCID: PMC6399074 DOI: 10.1007/s00285-018-1280-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/20/2018] [Indexed: 11/29/2022]
Abstract
Prions are proteins capable of adopting misfolded conformations and transmitting these conformations to other normally folded proteins. Prions are most commonly known for causing fatal neurodegenerative diseases in mammals but are also associated with several harmless phenotypes in yeast. A distinct feature of prion propagation is the existence of different phenotypical variants, called strains. It is widely accepted that these strains correspond to different conformational states of the protein, but the mechanisms driving their interactions remain poorly understood. This study uses mathematical modeling to provide insight into this problem. We show that the classical model of prion dynamics allows at most one conformational strain to stably propagate. In order to conform to biological observations of strain coexistence and co-stability, we develop an extension of the classical model by introducing a novel prion species consistent with biological studies. Qualitative analysis of this model reveals a new variety of behavior. Indeed, it allows for stable coexistence of different strains in a wide parameter range, and it also introduces intricate initial condition dependency. These new behaviors are consistent with experimental observations of prions in both mammals and yeast. As such, our model provides a valuable tool for investigating the underlying mechanisms of prion propagation and the link between prion strains and strain specific phenotypes. The consideration of a novel prion species brings a change in perspective on prion biology and we use our model to generate hypotheses about prion infectivity.
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Affiliation(s)
- Paul Lemarre
- School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, CA, 95343, USA
| | - Laurent Pujo-Menjouet
- Institut Camille Jordan, Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5208, 43 blvd. du 11 novembre 1918, 69622, Villeurbanne cedex, France.,Team Dracula, INRIA, 69603, Villeurbanne cedex, France
| | - Suzanne S Sindi
- Applied Mathematics School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, CA, 95343, USA.
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21
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Prion acute synaptotoxicity is largely driven by protease-resistant PrPSc species. PLoS Pathog 2018; 14:e1007214. [PMID: 30089152 PMCID: PMC6101418 DOI: 10.1371/journal.ppat.1007214] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 08/20/2018] [Accepted: 07/12/2018] [Indexed: 01/09/2023] Open
Abstract
Although misfolding of normal prion protein (PrPC) into abnormal conformers (PrPSc) is critical for prion disease pathogenesis our current understanding of the underlying molecular pathophysiology is rudimentary. Exploiting an electrophysiology paradigm, herein we report that at least modestly proteinase K (PK)-resistant PrPSc (PrPres) species are acutely synaptotoxic. Brief exposure to ex vivo PrPSc from two mouse-adapted prion strains (M1000 and MU02) prepared as crude brain homogenates (cM1000 and cMU02) and cell lysates from chronically M1000-infected RK13 cells (MoRK13-Inf) caused significant impairment of hippocampal CA1 region long-term potentiation (LTP), with the LTP disruption approximating that reported during the evolution of murine prion disease. Proof of PrPSc (especially PrPres) species as the synaptotoxic agent was demonstrated by: significant rescue of LTP following selective immuno-depletion of total PrP from cM1000 (dM1000); modestly PK-treated cM1000 (PK+M1000) retaining full synaptotoxicity; and restoration of the LTP impairment when employing reconstituted, PK-eluted, immuno-precipitated M1000 preparations (PK+IP-M1000). Additional detailed electrophysiological analyses exemplified by impairment of post-tetanic potentiation (PTP) suggest possible heightened pre-synaptic vulnerability to the acute synaptotoxicity. This dysfunction correlated with cumulative insufficiency of replenishment of the readily releasable pool (RRP) of vesicles during repeated high-frequency stimulation utilised for induction of LTP. Broadly comparable results with LTP and PTP impairment were obtained utilizing hippocampal slices from PrPC knockout (PrPo/o) mice, with cM1000 serial dilution assessments revealing similar sensitivity of PrPo/o and wild type (WT) slices. Size fractionation chromatography demonstrated that synaptotoxic PrP correlated with PK-resistant species >100kDa, consistent with multimeric PrPSc, with levels of these species >6 ng/ml appearing sufficient to induce synaptic dysfunction. Biochemical analyses of hippocampal slices manifesting acute synaptotoxicity demonstrated reduced levels of multiple key synaptic proteins, albeit with noteworthy differences in PrPo/o slices, while such changes were absent in hippocampi demonstrating rescued LTP through treatment with dM1000. Our findings offer important new mechanistic insights into the synaptic impairment underlying prion disease, enhancing prospects for development of targeted effective therapies. Misfolding of the normal prion protein (PrPC) into disease-associated conformations (PrPSc) is the critical initiating step for prion diseases. Similar to other neurodegenerative disorders, progressive failure of brain synapses is considered a primary deleterious event underpinning prion disease evolution. Our current understanding of the underlying mechanisms associated with synaptic failure is rudimentary contributing to difficulties in developing effective treatments. Herein we report the use of an electrophysiology paradigm that allowed us to demonstrate that at least modestly proteinase K (PK)-resistant PrPSc species from two mouse-adapted prion strains (M1000 and MU02) are directly synaptotoxic causing significant acute impairment of hippocampal CA1 region long-term potentiation (LTP). Of note, the LTP disruption approximated that reported in prion animal models. Additional detailed analyses provided novel pathophysiological insights suggesting possible heightened pre-synaptic vulnerability to the acute synaptotoxicity through impairment of replenishment of the readily releasable pool of neurotransmitter vesicles, while biochemical analyses demonstrated reduced levels of multiple key pre-and post-synaptic proteins. Broadly similar acute synaptic dysfunction and dose-response susceptibility were observed in slices from mice not expressing PrPC albeit with minor but noteworthy differences in electrophysiological and biochemical findings. Our study offers important new mechanistic insights into the synaptic impairment underlying prion disease, enhancing prospects for development effective therapies.
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22
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Glaves JP, Ladner-Keay CL, Bjorndahl TC, Wishart DS, Sykes BD. Residue-specific mobility changes in soluble oligomers of the prion protein define regions involved in aggregation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:982-988. [PMID: 29935976 DOI: 10.1016/j.bbapap.2018.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/15/2018] [Accepted: 06/20/2018] [Indexed: 12/12/2022]
Abstract
Prion (PrP) diseases are neurodegenerative diseases characterized by the formation of β-sheet rich, insoluble and protease resistant protein deposits (called PrPSc) that occur throughout the brain. Formation of synthetic or in vitro PrPSc can occur through on-pathway toxic oligomers. Similarly, toxic and infectious oligomers identified in cell and animal models of prion disease indicate that soluble oligomers are likely intermediates in the formation of insoluble PrPSc. Despite the critical role of prion oligomers in disease progression, little is known about their structure. In order, to obtain structural insight into prion oligomers, we generated oligomers by shaking-induced conversion of recombinant, monomeric prion protein PrPc (spanning residues 90-231). We then obtained two-dimensional solution NMR spectra of the PrPc monomer, a 40% converted oligomer, and a 94% converted oligomer. Heteronuclear single-quantum correlation (1H-15N) studies revealed that, in comparison to monomeric PrPc, the oligomer has intense amide peak signals in the N-terminal (residues 90-114) and C-terminal regions (residues 226-231). Furthermore, a core region with decreased mobility is revealed from residues ~127 to 225. Within this core oligomer region with decreased mobility, there is a pocket of increased amide peak signal corresponding to the middle of α-helix 2 and the loop between α-helices 2 and 3 in the PrPc monomer structure. Using high-resolution solution-state NMR, this work reveals detailed and divergent residue-specific changes in soluble oligomeric models of PrP.
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Affiliation(s)
- John Paul Glaves
- Department of Biochemistry, University of Alberta, Edmonton T6G 2H7, Canada
| | - Carol L Ladner-Keay
- Department of Biological Sciences, University of Alberta, Edmonton T6G 2E9, Canada
| | - Trent C Bjorndahl
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 2M9, Canada
| | - David S Wishart
- Department of Biological Sciences, University of Alberta, Edmonton T6G 2E9, Canada.
| | - Brian D Sykes
- Department of Biochemistry, University of Alberta, Edmonton T6G 2H7, Canada
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T. Islam AM, Adlard PA, Finkelstein DI, Lewis V, Biggi S, Biasini E, Collins SJ. Acute Neurotoxicity Models of Prion Disease. ACS Chem Neurosci 2018; 9:431-445. [PMID: 29393619 DOI: 10.1021/acschemneuro.7b00517] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Prion diseases are phenotypically diverse, transmissible, neurodegenerative disorders affecting both animals and humans. Misfolding of the normal prion protein (PrPC) into disease-associated conformers (PrPSc) is considered the critical etiological event underpinning prion diseases, with such misfolded isoforms linked to both disease transmission and neurotoxicity. Although important advances in our understanding of prion biology and pathogenesis have occurred over the last 3-4 decades, many fundamental questions remain to be resolved, including consensus regarding the principal pathways subserving neuronal dysfunction, as well as detailed biophysical characterization of PrPSc species transmitting disease and/or directly associated with neurotoxicity. In vivo and in vitro models have been, and remain, critical to furthering our understanding across many aspects of prion disease patho-biology. Prion animal models are arguably the most authentic in vivo models of neurodegeneration that exist and have provided valuable and multifarious insights into pathogenesis; however, they are expensive and time-consuming, and it can be problematic to clearly discern evidence of direct PrPSc neurotoxicity in the overall context of pathogenesis. In vitro models, in contrast, generally offer greater tractability and appear more suited to assessments of direct acute neurotoxicity but have until recently been relatively simplistic, and overall there remains a relative paucity of validated, biologically relevant models with heightened reliability as far as translational insights, contributing to difficulties in redressing our knowledge gaps in prion disease pathogenesis. In this review, we provide an overview of the spectrum and methodological diversity of in vivo and in vitro models of prion acute toxicity, as well as the pathogenic insights gained from these studies.
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Affiliation(s)
| | | | | | | | - S. Biggi
- CIBIO, University of Trento, 38123 Povo, Trento, Italy
| | - E. Biasini
- CIBIO, University of Trento, 38123 Povo, Trento, Italy
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24
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The function of the cellular prion protein in health and disease. Acta Neuropathol 2018; 135:159-178. [PMID: 29151170 DOI: 10.1007/s00401-017-1790-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 12/11/2022]
Abstract
The essential role of the cellular prion protein (PrPC) in prion disorders such as Creutzfeldt-Jakob disease is well documented. Moreover, evidence is accumulating that PrPC may act as a receptor for protein aggregates and transduce neurotoxic signals in more common neurodegenerative disorders, such as Alzheimer's disease. Although the pathological roles of PrPC have been thoroughly characterized, a general consensus on its physiological function within the brain has not yet been established. Knockout studies in various organisms, ranging from zebrafish to mice, have implicated PrPC in a diverse range of nervous system-related activities that include a key role in the maintenance of peripheral nerve myelination as well as a general ability to protect against neurotoxic stimuli. Thus, the function of PrPC may be multifaceted, with different cell types taking advantage of unique aspects of its biology. Deciphering the cellular function(s) of PrPC and the consequences of its absence is not simply an academic curiosity, since lowering PrPC levels in the brain is predicted to be a powerful therapeutic strategy for the treatment of prion disease. In this review, we outline the various approaches that have been employed in an effort to uncover the physiological and pathological functions of PrPC. While these studies have revealed important clues about the biology of the prion protein, the precise reason for PrPC's existence remains enigmatic.
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25
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Ladner-Keay CL, LeVatte M, Wishart DS. Role of polysaccharide and lipid in lipopolysaccharide induced prion protein conversion. Prion 2017; 10:466-483. [PMID: 27906600 PMCID: PMC5161299 DOI: 10.1080/19336896.2016.1254857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Conversion of native cellular prion protein (PrPc) from an α-helical structure to a toxic and infectious β-sheet structure (PrPSc) is a critical step in the development of prion disease. There are some indications that the formation of PrPSc is preceded by a β-sheet rich PrP (PrPβ) form which is non-infectious, but is an intermediate in the formation of infectious PrPSc. Furthermore the presence of lipid cofactors is thought to be critical in the formation of both intermediate-PrPβ and lethal, infectious PrPSc. We previously discovered that the endotoxin, lipopolysaccharide (LPS), interacts with recombinant PrPc and induces rapid conformational change to a β-sheet rich structure. This LPS induced PrPβ structure exhibits PrPSc-like features including proteinase K (PK) resistance and the capacity to form large oligomers and rod-like fibrils. LPS is a large, complex molecule with lipid, polysaccharide, 2-keto-3-deoxyoctonate (Kdo) and glucosamine components. To learn more about which LPS chemical constituents are critical for binding PrPc and inducing β-sheet conversion we systematically investigated which chemical components of LPS either bind or induce PrP conversion to PrPβ. We analyzed this PrP conversion using resolution enhanced native acidic gel electrophoresis (RENAGE), tryptophan fluorescence, circular dichroism, electron microscopy and PK resistance. Our results indicate that a minimal version of LPS (called detoxified and partially de-acylated LPS or dLPS) containing a portion of the polysaccharide and a portion of the lipid component is sufficient for PrP conversion. Lipid components, alone, and saccharide components, alone, are insufficient for conversion.
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Affiliation(s)
- Carol L Ladner-Keay
- a Department of Biological Sciences , University of Alberta , Edmonton , Alberta , Canada
| | - Marcia LeVatte
- a Department of Biological Sciences , University of Alberta , Edmonton , Alberta , Canada
| | - David S Wishart
- a Department of Biological Sciences , University of Alberta , Edmonton , Alberta , Canada.,b Department of Computing Science , University of Alberta , Edmonton , Alberta , Canada
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26
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Allison WT, DuVal MG, Nguyen-Phuoc K, Leighton PLA. Reduced Abundance and Subverted Functions of Proteins in Prion-Like Diseases: Gained Functions Fascinate but Lost Functions Affect Aetiology. Int J Mol Sci 2017; 18:E2223. [PMID: 29064456 PMCID: PMC5666902 DOI: 10.3390/ijms18102223] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/18/2017] [Accepted: 10/20/2017] [Indexed: 12/12/2022] Open
Abstract
Prions have served as pathfinders that reveal many aspects of proteostasis in neurons. The recent realization that several prominent neurodegenerative diseases spread via a prion-like mechanism illuminates new possibilities for diagnostics and therapeutics. Thus, key proteins in Alzheimer Disease and Amyotrophic lateral sclerosis (ALS), including amyloid-β precursor protein, Tau and superoxide dismutase 1 (SOD1), spread to adjacent cells in their misfolded aggregated forms and exhibit template-directed misfolding to induce further misfolding, disruptions to proteostasis and toxicity. Here we invert this comparison to ask what these prion-like diseases can teach us about the broad prion disease class, especially regarding the loss of these key proteins' function(s) as they misfold and aggregate. We also consider whether functional amyloids might reveal a role for subverted protein function in neurodegenerative disease. Our synthesis identifies SOD1 as an exemplar of protein functions being lost during prion-like protein misfolding, because SOD1 is inherently unstable and loses function in its misfolded disease-associated form. This has under-appreciated parallels amongst the canonical prion diseases, wherein the normally folded prion protein, PrPC, is reduced in abundance in fatal familial insomnia patients and during the preclinical phase in animal models, apparently via proteostatic mechanisms. Thus while template-directed misfolding and infectious properties represent gain-of-function that fascinates proteostasis researchers and defines (is required for) the prion(-like) diseases, loss and subversion of the functions attributed to hallmark proteins in neurodegenerative disease needs to be integrated into design towards effective therapeutics. We propose experiments to uniquely test these ideas.
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Affiliation(s)
- W Ted Allison
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2M8, Canada.
| | - Michèle G DuVal
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
| | - Kim Nguyen-Phuoc
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2M8, Canada.
| | - Patricia L A Leighton
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
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27
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Senesi M, Lewis V, Kim JH, Adlard PA, Finkelstein DI, Collins SJ. In vivo prion models and the disconnection between transmissibility and neurotoxicity. Ageing Res Rev 2017; 36:156-164. [PMID: 28450269 DOI: 10.1016/j.arr.2017.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Revised: 02/03/2017] [Accepted: 03/17/2017] [Indexed: 02/01/2023]
Abstract
The primary causative event in the development of prion diseases is the misfolding of the normal prion protein (PrPC) into an ensemble of altered conformers (herein collectively denoted as PrPSc) that accumulate in the brain. Prominent amongst currently unresolved key aspects underpinning prion disease pathogenesis is whether transmission and toxicity are sub-served by different molecular species of PrPSc, which may directly impact on the development of effective targeted treatments. The use of murine models of prion disease has been of fundamental importance for probing the relationship between hypothesised "neurotoxic" and "transmissible" PrPSc and the associated kinetic profiles of their production during disease evolution, but unfortunately consensus has not been achieved. Recent in vivo studies have led to formulation of the "two-phase" hypothesis, which postulates that there is first an exponential increase in transmitting PrPSc species followed by an abrupt transition to propagation of neurotoxic PrPSc species. Such observations however, appear inconsistent with previous in vivo murine studies employing detailed time-course behavioural testing, wherein evidence of neurotoxicity could be detected early in disease progression. This review analyses the contributions of in vivo murine models attempting to provide insights into the relationship between transmitting and neurotoxic PrPSc species and explores possible refinements to the "two-phase hypothesis", that better accommodate the available historical and recent evidence.
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Affiliation(s)
- Matteo Senesi
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville 3010, Australia
| | - Victoria Lewis
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville 3010, Australia
| | - Jee H Kim
- The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville 3010, Australia
| | - Paul A Adlard
- The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville 3010, Australia
| | - David I Finkelstein
- The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville 3010, Australia
| | - Steven J Collins
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville 3010, Australia; The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville 3010, Australia.
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28
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Fernandez-Funez P, Sanchez-Garcia J, Rincon-Limas DE. Drosophila models of prionopathies: insight into prion protein function, transmission, and neurotoxicity. Curr Opin Genet Dev 2017; 44:141-148. [PMID: 28415023 PMCID: PMC5474952 DOI: 10.1016/j.gde.2017.03.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/03/2017] [Accepted: 03/21/2017] [Indexed: 11/26/2022]
Abstract
Prion diseases (PrD) are unique neurodegenerative conditions with sporadic, genetic, and infectious etiologies. The agent responsible for these pathologies is a misfolded conformation of the prion protein (PrP). Although a process of autocatalytic "conversion" is known to mediate disease transmission, important gaps still remain regarding the physiological function of PrP and its relevance to pathogenesis, the molecular and cellular mechanisms mediating neurotoxicity and transmission, and the PrP conformations responsible for neurotoxicity. New Drosophila models expressing mammalian PrP have revealed physiological insight into PrP function and opened the door to significant progress in prion transmission and PrP neurotoxicity. Importantly, flies expressing human PrP showing a robust eye phenotype will allow performing genetic screens to uncover novel mechanisms mediating PrP neurotoxicity.
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Affiliation(s)
- Pedro Fernandez-Funez
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN 55811, USA.
| | - Jonatan Sanchez-Garcia
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Diego E Rincon-Limas
- Departments of Neurology and Neuroscience, McKnight Brain Institute and Center for Translational Research on Neurodegenerative Diseases, University of Florida, Gainesville, FL 32611, USA
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29
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Shah SZA, Zhao D, Hussain T, Yang L. The Role of Unfolded Protein Response and Mitogen-Activated Protein Kinase Signaling in Neurodegenerative Diseases with Special Focus on Prion Diseases. Front Aging Neurosci 2017; 9:120. [PMID: 28507517 PMCID: PMC5410568 DOI: 10.3389/fnagi.2017.00120] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 04/12/2017] [Indexed: 12/25/2022] Open
Abstract
Prion diseases are neurodegenerative pathologies characterized by the accumulation of a protease-resistant form of the cellular prion protein named prion protein scrapie (PrPSc) in the brain. PrPSc accumulation in the endoplasmic reticulum (ER) result in a dysregulated calcium (Ca2+) homeostasis and subsequent initiation of unfolded protein response (UPR) leading to neuronal dysfunction and apoptosis. The molecular mechanisms for the transition between adaptation to ER stress and ER stress-induced apoptosis are still unclear. Mitogen-activated protein kinases (MAPKs) are serine/threonine protein kinases that rule the signaling of many extracellular stimuli from plasma membrane to the nucleus. However the identification of numerous points of cross talk between the UPR and MAPK signaling pathways may contribute to our understanding of the consequences of ER stress in prion diseases. Indeed the MAPK signaling network is known to regulate cell cycle progression and cell survival or death responses following a variety of stresses including misfolded protein response stress. In this article, we review the UPR signaling in prion diseases and discuss the triad of MAPK signaling pathways. We also describe the role played by MAPK signaling cascades in Alzheimer’s (AD) and Parkinson’s disease (PD). We will also overview the mechanisms of cell death and the role of MAPK signaling in prion disease progression and highlight potential avenues for therapeutic intervention.
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Affiliation(s)
- Syed Zahid Ali Shah
- National Animal Transmissible Spongiform Encephalopathy Laboratory and Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural UniversityBeijing, China
| | - Deming Zhao
- National Animal Transmissible Spongiform Encephalopathy Laboratory and Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural UniversityBeijing, China
| | - Tariq Hussain
- National Animal Transmissible Spongiform Encephalopathy Laboratory and Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural UniversityBeijing, China
| | - Lifeng Yang
- National Animal Transmissible Spongiform Encephalopathy Laboratory and Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural UniversityBeijing, China
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30
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Abstract
Prion diseases affect a wide range of mammal species and are caused by a misfolded self-propagating isoform (PrPSc) of the normal prion protein (PrPC). Distinct strains of prions exist and are operationally defined by differences in a heritable phenotype under controlled experimental transmission conditions. Prion strains can differ in incubation period, clinical signs of disease, tissue tropism, and host range. The mechanism by which a protein-only pathogen can encode strain diversity is only beginning to be understood. The prevailing hypothesis is that prion strain diversity is encoded by strain-specific conformations of PrPSc; however, strain-specific cellular cofactors have been identified in vitro that may also contribute to prion strain diversity. Although much progress has been made on understanding the etiological agent of prion disease, the relationship between the strain-specific properties of PrPSc and the resulting phenotype of disease in animals is poorly understood.
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Affiliation(s)
- Jason C Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska 68178
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31
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Mays CE, Soto C. The stress of prion disease. Brain Res 2016; 1648:553-560. [PMID: 27060771 DOI: 10.1016/j.brainres.2016.04.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 04/01/2016] [Accepted: 04/05/2016] [Indexed: 01/31/2023]
Abstract
Prion diseases are fatal neurodegenerative disorders that include scrapie of sheep, bovine spongiform encephalopathy of cattle, chronic wasting disease of cervids, and Creutzfeldt-Jakob disease (CJD) of humans. The etiology for prion diseases can be infectious, sporadic, or hereditary. However, the common denominator for all types is the formation of a transmissible agent composed of a β-sheet-rich, misfolded version of the host-encoded prion protein (PrPC), known as PrPSc. PrPSc self-replicates through a template-assisted process that converts the α-helical conformation of PrPC into the disease-associated isoform. In parallel with PrPSc accumulation, spongiform change is pathologically observed in the central nervous system, where "holes" appear because of massive neuronal death. Here, we review the cellular pathways triggered in response to PrPSc formation and accumulation. Available data suggest that neuronal dysfunction and death may be caused by what originates as a cellular pro-survival response to chronic PrPSc accumulation. We also discuss what is known about the complex cross-talk between the endoplasmic reticulum stress components and the quality control pathways. Better knowledge about these processes may lead to innovative therapeutic strategies based on manipulating the stress response and its consequences for neurodegeneration. This article is part of a Special Issue entitled SI:ER stress.
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Affiliation(s)
- Charles E Mays
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX 77030, USA
| | - Claudio Soto
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX 77030, USA.
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32
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Ugalde CL, Finkelstein DI, Lawson VA, Hill AF. Pathogenic mechanisms of prion protein, amyloid-β and α-synuclein misfolding: the prion concept and neurotoxicity of protein oligomers. J Neurochem 2016; 139:162-180. [PMID: 27529376 DOI: 10.1111/jnc.13772] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 07/24/2016] [Accepted: 08/09/2016] [Indexed: 12/21/2022]
Abstract
Proteinopathies represent a group of diseases characterized by the unregulated misfolding and aggregation of proteins. Accumulation of misfolded protein in the central nervous system (CNS) is associated with neurodegenerative diseases, such as the transmissible spongiform encephalopathies (or prion diseases), Alzheimer's disease, and the synucleinopathies (the most common of which is Parkinson's disease). Of these, the pathogenic mechanisms of prion diseases are particularly striking where the transmissible, causative agent of disease is the prion, or proteinaceous infectious particle. Prions are composed almost exclusively of PrPSc ; a misfolded isoform of the normal cellular protein, PrPC , which is found accumulated in the CNS in disease. Today, mounting evidence suggests other aggregating proteins, such as amyloid-β (Aβ) and α-synuclein (α-syn), proteins associated with Alzheimer's disease and synucleinopathies, respectively, share similar biophysical and biochemical properties with PrPSc that influences how they misfold, aggregate, and propagate in disease. In this regard, the definition of a 'prion' may ultimately expand to include other pathogenic proteins. Unifying knowledge of folded proteins may also reveal common mechanisms associated with other features of disease that are less understood, such as neurotoxicity. This review discusses the common features Aβ and α-syn share with PrP and neurotoxic mechanisms associated with these misfolded proteins. Several proteins are known to misfold and accumulate in the central nervous system causing a range of neurodegenerative diseases, such as Alzheimer's, Parkinson's, and the prion diseases. Prions are transmissible misfolded conformers of the prion protein, PrP, which seed further generation of infectious proteins. Similar effects have recently been observed in proteins associated with Alzheimer's disease and the synucleinopathies, leading to the proposition that the definition of a 'prion' may ultimately expand to include other pathogenic proteins. Unifying knowledge of misfolded proteins may also reveal common mechanisms associated with other features of disease that are less understood, such as neurotoxicity.
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Affiliation(s)
- Cathryn L Ugalde
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Vic., Australia.,Howard Florey Institute of Neuroscience and Mental Health, Parkville, Vic., Australia.,Department of Pathology, University of Melbourne, Parkville, Vic., Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Vic., Australia
| | - David I Finkelstein
- Howard Florey Institute of Neuroscience and Mental Health, Parkville, Vic., Australia
| | - Victoria A Lawson
- Department of Pathology, University of Melbourne, Parkville, Vic., Australia
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Vic., Australia. .,Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Vic., Australia.
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