201
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A Neuronal Culture System to Detect Prion Synaptotoxicity. PLoS Pathog 2016; 12:e1005623. [PMID: 27227882 PMCID: PMC4881977 DOI: 10.1371/journal.ppat.1005623] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/19/2016] [Indexed: 12/02/2022] Open
Abstract
Synaptic pathology is an early feature of prion as well as other neurodegenerative diseases. Although the self-templating process by which prions propagate is well established, the mechanisms by which prions cause synaptotoxicity are poorly understood, due largely to the absence of experimentally tractable cell culture models. Here, we report that exposure of cultured hippocampal neurons to PrPSc, the infectious isoform of the prion protein, results in rapid retraction of dendritic spines. This effect is entirely dependent on expression of the cellular prion protein, PrPC, by target neurons, and on the presence of a nine-amino acid, polybasic region at the N-terminus of the PrPC molecule. Both protease-resistant and protease-sensitive forms of PrPSc cause dendritic loss. This system provides new insights into the mechanisms responsible for prion neurotoxicity, and it provides a platform for characterizing different pathogenic forms of PrPSc and testing potential therapeutic agents. Prion diseases are fatal neurodegenerative disorders that cause memory loss, impaired coordination, and abnormal movements. The molecular culprit in prion diseases is PrPSc, an infectious isoform of a host-encoded glycoprotein (PrPC) that can propagate itself by a self-templating mechanism. Whether PrPSc itself is toxic to neurons, and if so, the cellular mechanisms by which it produces neuronal pathology are largely unknown, in part because of the absence of suitable cell culture models. We describe here a hippocampal neuronal cultural system to detect the toxic effect of PrPSc on dendritic spines, which are postsynaptic elements responsible for excitatory synaptic transmission, and which are implicated in learning, memory, and the earliest stages of neurodegenerative diseases. We found that purified, exogenously applied PrPSc causes acute retraction of dendritic spines, an effect that is entirely dependent on expression of PrPC by target neurons, and on the on the presence of a nine-amino acid, polybasic region at the N-terminus of the PrPC molecule. Both protease-resistant and protease-sensitive forms of PrPSc cause dendritic retraction. This system provides new insights into the mechanisms responsible for prion neurotoxicity, and it provides a platform for characterizing different pathogenic forms of PrPSc and testing potential therapeutic agents.
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203
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Increases of Galectin-1 and its S-nitrosylated form in the Brain Tissues of Scrapie-Infected Rodent Models and Human Prion Diseases. Mol Neurobiol 2016; 54:3707-3716. [PMID: 27211330 DOI: 10.1007/s12035-016-9923-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/03/2016] [Indexed: 12/11/2022]
Abstract
Galectin-1 (Gal-1) shows neuroprotective activity in brain ischemia, spinal cord injury, and autoimmune neuroinflammation. To evaluate the Gal-1 situation in the brains of prion disease, the brain levels of Gal-1 in several scrapie-infected experimental rodent models were tested by Western blot, including agents 263K-infected hamsters, 139A-, ME7-, and S15-infected mice. Remarkable increases of brain Gal-1 were observed in all tested scrapie-infected rodents at the terminal stage. The brain levels of Gal-1 showed time-dependent increases along with the prolonging of incubation times. Immunohistochemical assays illustrated much stronger stainings in the brain sections of scrapie-infected rodents. Quantitative RT-PCR of Gal-1 gene demonstrated increased transcription in the brains of scrapie-infected mice. Gal-1 was colocalized with GFAP- and NeuN-positive cells, but not with Iba-1-positive cells in immunofluorescent test. Increases of Gal-1 were also detected in the several postmortem cortex regions of human prion diseases. Moreover, the S-nitrosylated forms of Gal-1 in the brains of scrapie-infected rodents were significantly higher than those of normal ones. Our finding here demonstrates markedly increased brain Gal-1 and S-nitrosylated Gal-1 both in scrapie-infected rodents and human prion diseases.
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204
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Carter L, Kim SJ, Schneidman-Duhovny D, Stöhr J, Poncet-Montange G, Weiss TM, Tsuruta H, Prusiner SB, Sali A. Prion Protein-Antibody Complexes Characterized by Chromatography-Coupled Small-Angle X-Ray Scattering. Biophys J 2016; 109:793-805. [PMID: 26287631 DOI: 10.1016/j.bpj.2015.06.065] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 06/22/2015] [Accepted: 06/30/2015] [Indexed: 10/23/2022] Open
Abstract
Aberrant self-assembly, induced by structural misfolding of the prion proteins, leads to a number of neurodegenerative disorders. In particular, misfolding of the mostly α-helical cellular prion protein (PrP(C)) into a β-sheet-rich disease-causing isoform (PrP(Sc)) is the key molecular event in the formation of PrP(Sc) aggregates. The molecular mechanisms underlying the PrP(C)-to-PrP(Sc) conversion and subsequent aggregation remain to be elucidated. However, in persistently prion-infected cell-culture models, it was shown that treatment with monoclonal antibodies against defined regions of the prion protein (PrP) led to the clearing of PrP(Sc) in cultured cells. To gain more insight into this process, we characterized PrP-antibody complexes in solution using a fast protein liquid chromatography coupled with small-angle x-ray scattering (FPLC-SAXS) procedure. High-quality SAXS data were collected for full-length recombinant mouse PrP [denoted recPrP(23-230)] and N-terminally truncated recPrP(89-230), as well as their complexes with each of two Fab fragments (HuM-P and HuM-R1), which recognize N- and C-terminal epitopes of PrP, respectively. In-line measurements by fast protein liquid chromatography coupled with SAXS minimized data artifacts caused by a non-monodispersed sample, allowing structural analysis of PrP alone and in complex with Fab antibodies. The resulting structural models suggest two mechanisms for how these Fabs may prevent the conversion of PrP(C) into PrP(Sc).
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Affiliation(s)
- Lester Carter
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California
| | - Seung Joong Kim
- Department of Bioengineering and Therapeutic Sciences and Department of Pharmaceutical Chemistry and California Institute for Quantitative Biosciences (QB3), University of California San Francisco, San Francisco, California
| | - Dina Schneidman-Duhovny
- Department of Bioengineering and Therapeutic Sciences and Department of Pharmaceutical Chemistry and California Institute for Quantitative Biosciences (QB3), University of California San Francisco, San Francisco, California
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, California; Department of Neurology, University of California San Francisco, San Francisco, California
| | - Guillaume Poncet-Montange
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, California
| | - Thomas M Weiss
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California
| | - Hiro Tsuruta
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, California; Department of Neurology, University of California San Francisco, San Francisco, California.
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences and Department of Pharmaceutical Chemistry and California Institute for Quantitative Biosciences (QB3), University of California San Francisco, San Francisco, California.
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205
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Bellato HM, Hajj GNM. Translational control by eIF2α in neurons: Beyond the stress response. Cytoskeleton (Hoboken) 2016; 73:551-565. [PMID: 26994324 DOI: 10.1002/cm.21294] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/14/2016] [Accepted: 03/14/2016] [Indexed: 12/21/2022]
Abstract
The translation of mRNAs is a tightly controlled process that responds to multiple signaling pathways. In neurons, this control is also exerted locally due to the differential necessity of proteins in axons and dendrites. The phosphorylation of the alpha subunit of the translation initiation factor 2 (eIF2α) is one of the mechanisms of translational control. The phosphorylation of eIF2α has classically been viewed as a stress response, halting translation initiation. However, in the nervous system this type of regulation has been related to other mechanisms besides stress response, such as behavior, memory consolidation and nervous system development. Additionally, neurodegenerative diseases have a major stress component, thus eIF2α phosphorylation plays a preeminent role and its modulation is currently viewed as a new opportunity for therapeutic interventions. This review consolidates current information regarding eIF2α phosphorylation in neurons and its impact in neurodegenerative diseases. © 2016 Wiley Periodicals, Inc.
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206
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Abstract
Although prions were first discovered through their link to severe brain degenerative diseases in animals, the emergence of prions as regulators of the phenotype of the yeast Saccharomyces cerevisiae and the filamentous fungus Podospora anserina has revealed a new facet of prion biology. In most cases, fungal prions are carried without apparent detriment to the host cell, representing a novel form of epigenetic inheritance. This raises the question of whether or not yeast prions are beneficial survival factors or actually gives rise to a "disease state" that is selected against in nature. To date, most studies on the impact of fungal prions have focused on laboratory-cultivated "domesticated" strains of S. cerevisiae. At least eight prions have now been described in this species, each with the potential to impact on a wide range of cellular processes. The discovery of prions in nondomesticated strains of S. cerevisiae and P. anserina has confirmed that prions are not simply an artifact of "domestication" of this species. In this review, I describe what we currently know about the phenotypic impact of fungal prions. I then describe how the interplay between host genotype and the prion-mediated changes can generate a wide array of phenotypic diversity. How such prion-generated diversity may be of benefit to the host in survival in a fluctuating, often hazardous environment is then outlined. Prion research has now entered a new phase in which we must now consider their biological function and evolutionary significance in the natural world.
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Affiliation(s)
- Mick F Tuite
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, United Kingdom.
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207
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Xerxa E, Barbisin M, Chieppa MN, Krmac H, Vallino Costassa E, Vatta P, Simmons M, Caramelli M, Casalone C, Corona C, Legname G. Whole Blood Gene Expression Profiling in Preclinical and Clinical Cattle Infected with Atypical Bovine Spongiform Encephalopathy. PLoS One 2016; 11:e0153425. [PMID: 27073865 PMCID: PMC4830546 DOI: 10.1371/journal.pone.0153425] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 03/29/2016] [Indexed: 12/12/2022] Open
Abstract
Prion diseases, such as bovine spongiform encephalopathies (BSE), are transmissible neurodegenerative disorders affecting humans and a wide variety of mammals. Variant Creutzfeldt-Jakob disease (vCJD), a prion disease in humans, has been linked to exposure to BSE prions. This classical BSE (cBSE) is now rapidly disappearing as a result of appropriate measures to control animal feeding. Besides cBSE, two atypical forms (named H- and L-type BSE) have recently been described in Europe, Japan, and North America. Here we describe the first wide-spectrum microarray analysis in whole blood of atypical BSE-infected cattle. Transcriptome changes in infected animals were analyzed prior to and after the onset of clinical signs. The microarray analysis revealed gene expression changes in blood prior to the appearance of the clinical signs and during the progression of the disease. A set of 32 differentially expressed genes was found to be in common between clinical and preclinical stages and showed a very similar expression pattern in the two phases. A 22-gene signature showed an oscillating pattern of expression, being differentially expressed in the preclinical stage and then going back to control levels in the symptomatic phase. One gene, SEL1L3, was downregulated during the progression of the disease. Most of the studies performed up to date utilized various tissues, which are not suitable for a rapid analysis of infected animals and patients. Our findings suggest the intriguing possibility to take advantage of whole blood RNA transcriptional profiling for the preclinical identification of prion infection. Further, this study highlighted several pathways, such as immune response and metabolism that may play an important role in peripheral prion pathogenesis. Finally, the gene expression changes identified in the present study may be further investigated as a fingerprint for monitoring the progression of disease and for developing targeted therapeutic interventions.
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Affiliation(s)
- Elena Xerxa
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Functional and Structural Genomics sector, Trieste, Italy
| | - Maura Barbisin
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Functional and Structural Genomics sector, Trieste, Italy
| | - Maria Novella Chieppa
- Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle d'Aosta, Torino, Italy
| | - Helena Krmac
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Functional and Structural Genomics sector, Trieste, Italy
| | - Elena Vallino Costassa
- Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle d'Aosta, Torino, Italy
| | - Paolo Vatta
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Functional and Structural Genomics sector, Trieste, Italy
| | - Marion Simmons
- Pathology Department, Animal and Plant Health Agency (Weybridge), New Haw, Addlestone, United Kingdom
| | - Maria Caramelli
- Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle d'Aosta, Torino, Italy
| | - Cristina Casalone
- Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle d'Aosta, Torino, Italy
| | - Cristiano Corona
- Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle d'Aosta, Torino, Italy
| | - Giuseppe Legname
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Functional and Structural Genomics sector, Trieste, Italy
- * E-mail:
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208
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Abstract
In recent years, prion protein (PrP(C)) has been considered as a promising target molecule for cancer therapies, due its direct or indirect participation in tumor growth, metastasis, and resistance to cell death induced by chemotherapy. PrP(C) functions as a scaffold protein, forming multiprotein complexes on the plasma membrane, which elicits distinct signaling pathways involved in diverse biological phenomena and could be modulated depending on the cell type, complex composition, and organization. In addition, PrP(C) and its partners participate in self-renewal of embryonic, tissue-specific stem cells and cancer stem cells, which are suggested to be responsible for the origin, maintenance, relapse, and dissemination of tumors. Interference with protein-protein interaction has been recognized as an important therapeutic strategy in cancer; indeed, the possible interference in PrP(C) engagement with specific partners is a novel strategy. Recently, our group successfully used that approach to interfere with the interaction between PrP(C) and HSP-90/70 organizing protein (HOP, also known as stress-inducible protein 1 - STI1) to control the growth of human glioblastoma in animal models. Thus, PrP(C)-organized multicomplexes have emerged as feasible candidates for anti-tumor therapy, warranting further exploration.
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Affiliation(s)
- Tiago G Santos
- a International Research Center; AC Camargo Cancer Center ; São Paulo , Brazil
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209
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Huang YW, Chang YC, Diaz-Avalos R, King CY. W8, a new Sup35 prion strain, transmits distinctive information with a conserved assembly scheme. Prion 2016; 9:207-27. [PMID: 26038983 DOI: 10.1080/19336896.2015.1039217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Prion strains are different self-propagating conformers of the same infectious protein. Three strains of the [PSI] prion, infectious forms of the yeast Sup35 protein, have been previously characterized in our laboratory. Here we report the discovery of a new [PSI] strain, named W8. We demonstrate its robust cellular propagation as well as the protein-only transmission. To reveal strain-specific sequence requirement, mutations that interfered with the propagation of W8 were identified by consecutive substitution of residues 5-55 of Sup35 by proline and insertion of glycine at alternate sites in this segment. Interestingly, propagating W8 with single mutations at residues 5-7 and around residue 43 caused the strain to transmute. In contrast to the assertion that [PSI] existed as a dynamic cloud of sub-structures, no random drift in transmission characteristics was detected in mitotically propagated W8 populations. Electron diffraction and mass-per-length measurements indicate that, similar to the 3 previously characterized strains, W8 fibers are composed of about 1 prion molecule per 4.7-Å cross-β repeat period. Thus differently folded single Sup35 molecules, not dimeric and trimeric assemblies, form the basic repeating units to build the 4 [PSI] strains.
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Key Words
- 5-FOA, 5-fluoroorotic acid
- Aβ, amyloid β-protein
- GFP, green fluorescent protein
- PrP, prion protein
- SC, synthetic complete
- STEM, scanning transmission electron microscopy
- YPD, yeast extract, peptone, dextrose
- amyloid, prion strain, [PSI+], SUP35, yeast
- mpl, mass per length
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Affiliation(s)
- Yu-Wen Huang
- a Molecular and Cell Biology; Taiwan International Graduate Program; Academia Sinica and National Defense Medical Center ; Taipei , Taiwan
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210
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Prion-like domains as epigenetic regulators, scaffolds for subcellular organization, and drivers of neurodegenerative disease. Brain Res 2016; 1647:9-18. [PMID: 26996412 PMCID: PMC5003744 DOI: 10.1016/j.brainres.2016.02.037] [Citation(s) in RCA: 163] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/19/2016] [Accepted: 02/20/2016] [Indexed: 12/12/2022]
Abstract
Key challenges faced by all cells include how to spatiotemporally organize complex biochemistry and how to respond to environmental fluctuations. The budding yeast Saccharomyces cerevisiae harnesses alternative protein folding mediated by yeast prion domains (PrDs) for rapid evolution of new traits in response to environmental stress. Increasingly, it is appreciated that low complexity domains similar in amino acid composition to yeast PrDs (prion-like domains; PrLDs) found in metazoa have a prominent role in subcellular cytoplasmic organization, especially in relation to RNA homeostasis. In this review, we highlight recent advances in our understanding of the role of prions in enabling rapid adaptation to environmental stress in yeast. We also present the complete list of human proteins with PrLDs and discuss the prevalence of the PrLD in nucleic-acid binding proteins that are often connected to neurodegenerative disease, including: ataxin 1, ataxin 2, FUS, TDP-43, TAF15, EWSR1, hnRNPA1, and hnRNPA2. Recent paradigm-shifting advances establish that PrLDs undergo phase transitions to liquid states, which contribute to the structure and biophysics of diverse membraneless organelles. This structural functionality of PrLDs, however, simultaneously increases their propensity for deleterious protein-misfolding events that drive neurodegenerative disease. We suggest that even these PrLD-misfolding events are not irreversible and can be mitigated by natural or engineered protein disaggregases, which could have important therapeutic applications.
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211
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Massignan T, Cimini S, Stincardini C, Cerovic M, Vanni I, Elezgarai SR, Moreno J, Stravalaci M, Negro A, Sangiovanni V, Restelli E, Riccardi G, Gobbi M, Castilla J, Borsello T, Nonno R, Biasini E. A cationic tetrapyrrole inhibits toxic activities of the cellular prion protein. Sci Rep 2016; 6:23180. [PMID: 26976106 PMCID: PMC4791597 DOI: 10.1038/srep23180] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/29/2016] [Indexed: 12/11/2022] Open
Abstract
Prion diseases are rare neurodegenerative conditions associated with the conformational conversion of the cellular prion protein (PrPC) into PrPSc, a self-replicating isoform (prion) that accumulates in the central nervous system of affected individuals. The structure of PrPSc is poorly defined, and likely to be heterogeneous, as suggested by the existence of different prion strains. The latter represents a relevant problem for therapy in prion diseases, as some potent anti-prion compounds have shown strain-specificity. Designing therapeutics that target PrPC may provide an opportunity to overcome these problems. PrPC ligands may theoretically inhibit the replication of multiple prion strains, by acting on the common substrate of any prion replication reaction. Here, we characterized the properties of a cationic tetrapyrrole [Fe(III)-TMPyP], which was previously shown to bind PrPC, and inhibit the replication of a mouse prion strain. We report that the compound is active against multiple prion strains in vitro and in cells. Interestingly, we also find that Fe(III)-TMPyP inhibits several PrPC-related toxic activities, including the channel-forming ability of a PrP mutant, and the PrPC-dependent synaptotoxicity of amyloid-β (Aβ) oligomers, which are associated with Alzheimer’s Disease. These results demonstrate that molecules binding to PrPC may produce a dual effect of blocking prion replication and inhibiting PrPC-mediated toxicity.
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Affiliation(s)
- Tania Massignan
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy.,Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Sara Cimini
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Claudia Stincardini
- Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Milica Cerovic
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Ilaria Vanni
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, 00161 Rome, Italy
| | - Saioa R Elezgarai
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy.,Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Jorge Moreno
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio 48160, Bizkaia, Spain
| | - Matteo Stravalaci
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Alessandro Negro
- Department of Biomedical Sciences, University of Padova, 35121 Padova, Italy
| | - Valeria Sangiovanni
- Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Elena Restelli
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Geraldina Riccardi
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, 00161 Rome, Italy
| | - Marco Gobbi
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Joaquín Castilla
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio 48160, Bizkaia, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Bizkaia, Spain
| | - Tiziana Borsello
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy.,Department of Pharmacological and Biomolecular Sciences, Milan University, 20133 Milan Italy
| | - Romolo Nonno
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, 00161 Rome, Italy
| | - Emiliano Biasini
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy.,Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, 00161 Rome, Italy.,Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
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212
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Zhou J, Du X, Yamagata N, Xu B. Enzyme-Instructed Self-Assembly of Small D-Peptides as a Multiple-Step Process for Selectively Killing Cancer Cells. J Am Chem Soc 2016; 138:3813-23. [PMID: 26966844 PMCID: PMC4830347 DOI: 10.1021/jacs.5b13541] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
Selective inhibition of cancer cells
remains a challenge in chemotherapy.
Here we report the molecular and cellular validation of enzyme-instructed
self-assembly (EISA) as a multiple step process for selectively killing
cancer cells that overexpress alkaline phosphatases (ALPs). We design
and synthesize two kinds of d-tetrapeptide containing one
or two phosphotyrosine residues and with the N-terminal capped by
a naphthyl group. Upon enzymatic dephosphorylation, these d-tetrapeptides turn into self-assembling molecules to form nanofibers
in water. Incubating these d-tetrapeptides with several cancer
cell lines and one normal cell line, the unphosphorylated d-tetrapeptides are innocuous to all the cell lines, the mono- and
diphosphorylated d-tetrapeptides selectively inhibit the
cancer cells, but not the normal cell. The monophosphorylated d-tetrapeptides exhibit more potent inhibitory activity than
the diphosphorylated d-tetrapeptides do; the cancer cell
lines express higher level of ALPs are more susceptible to inhibition
by the phosphorylated d-tetrapeptides; the precursors of d-tetrapeptides that possess higher self-assembling abilities
exhibit higher inhibitory activities. These results confirm the important
role of enzymatic reaction and self-assembly. Using uncompetitive
inhibitors of ALPs and fluorescent d-tetrapeptides, we delineate
that the enzyme catalyzed dephosphorylation and the self-assembly
steps, together, result in the localization of the nanofibers of d-tetrapeptides for killing the cancer cells. We find that the
cell death modality likely associates with the cell type and prove
the interactions between nanofibers and the death receptors. This
work illustrates a paradigm-shifting and biomimetic approach and contributes
useful molecular insights for the development of spatiotemporal defined
supramolecular processes/assemblies as potential anticancer therapeutics.
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Affiliation(s)
- Jie Zhou
- Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02453, United States
| | - Xuewen Du
- Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02453, United States
| | - Natsuko Yamagata
- Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02453, United States
| | - Bing Xu
- Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02453, United States
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213
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Do prion protein gene polymorphisms induce apoptosis in non-mammals? J Biosci 2016; 41:97-107. [PMID: 26949092 DOI: 10.1007/s12038-015-9584-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Genetic variations such as single nucleotide polymorphisms (SNPs) in prion protein coding gene, Prnp, greatly affect susceptibility to prion diseases in mammals. Here, the coding region of Prnp was screened for polymorphisms in redeared turtle, Trachemys scripta. Four polymorphisms, L203V, N205I, V225A and M237V, were common in 15 out of 30 turtles; in one sample, three SNPs, L203V, N205I and M237V, and in the remaining 14 samples, only L203V and N205I polymorphisms, were investigated. Besides, C658T, C664T, C670A and C823A SNPs were silent mutations. To elucidate the relationship between the SNPs and apoptosis, TUNEL assays and active caspase-3 immunodetection techniques in brain sections of the polymorphic samples were performed. The results revealed that TUNEL-positive cells and active caspase-3-positive cells in the turtles with four polymorphisms were significantly increased compared with those of the turtles with two polymorphisms (P less than 0.01 and P less than 0.05, respectively). In conclusion, this study provides preliminary information about the possible relationship between SNPs within the Prnp locus and apoptosis in a non-mammalian species, Trachemys scripta, in which prion disease has never been reported.
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214
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CSF biomarkers in neurodegenerative and vascular dementias. Prog Neurobiol 2016; 138-140:36-53. [DOI: 10.1016/j.pneurobio.2016.03.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/12/2016] [Accepted: 03/14/2016] [Indexed: 12/14/2022]
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215
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Kang SG, Kim C, Cortez LM, Carmen Garza M, Yang J, Wille H, Sim VL, Westaway D, McKenzie D, Aiken J. Toll-like receptor-mediated immune response inhibits prion propagation. Glia 2016; 64:937-51. [PMID: 26880394 DOI: 10.1002/glia.22973] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 02/03/2023]
Abstract
Prion diseases are progressive neurodegenerative disorders affecting humans and various mammals. The prominent neuropathological change in prion diseases is neuroinflammation characterized by activation of neuroglia surrounding prion deposition. The cause and effect of this cellular response, however, is unclear. We investigated innate immune defenses against prion infection using primary mixed neuronal and glial cultures. Conditional prion propagation occurred in glial cultures depending on their immune status. Preconditioning of the cells with the toll-like receptor (TLR) ligand, lipopolysaccharide, resulted in a reduction in prion propagation, whereas suppression of the immune responses with the synthetic glucocorticoid, dexamethasone, increased prion propagation. In response to recombinant prion fibrils, glial cells up-regulated TLRs (TLR1 and TLR2) expression and secreted cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-6, granulocyte-macrophage colony-stimulating factor, and interferon-β). Preconditioning of neuronal and glial cultures with recombinant prion fibrils inhibited prion replication and altered microglial and astrocytic populations. Our results provide evidence that, in early stages of prion infection, glial cells respond to prion infection through TLR-mediated innate immunity.
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Affiliation(s)
- Sang-Gyun Kang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Chiye Kim
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Leonardo M Cortez
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - María Carmen Garza
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Jing Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Holger Wille
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.,Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Valerie L Sim
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Debbie McKenzie
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.,Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Judd Aiken
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.,Department of Agricultural, Food, and Nutritional Sciences, University of Alberta, Edmonton, Alberta, Canada
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216
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Lee Y, Lee D, Choi I, Song Y, Kang MJ, Kang SW. Single octapeptide deletion selectively processes a pathogenic prion protein mutant on the cell surface. Biochem Biophys Res Commun 2016; 470:263-268. [PMID: 26774341 DOI: 10.1016/j.bbrc.2016.01.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 01/12/2016] [Indexed: 11/30/2022]
Abstract
The number of octapeptide repeats has been considered to correlate with clinical and pathogenic phenotypes of prion diseases resulting from aberrant metabolism of prion protein (PrP). However, it is still poorly understood how this motif affects PrP metabolism. Here, we discover homozygous single octapeptide repeat deletion mutation in the PRNP gene encoding PrP in HeLa cells. The level of PrP proves to be unaffected by this mutation alone, but selectively reduced by additional pathogenic mutations within internal hydrophobic region of PrP. The pattern and relative amount of newly synthesized A117V mutant is unaffected, whereas the mutant appears to be differentially distributed and processed on the cell surface by single octapeptide deletion. This study provides an insight into a novel mutant-specific metabolism of PrP on the cell surface.
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Affiliation(s)
- Yumi Lee
- Department of Biomedical Sciences, University of Ulsan College of Medicine & Asan Institute of Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Duri Lee
- Department of Biomedical Sciences, University of Ulsan College of Medicine & Asan Institute of Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Ilho Choi
- Department of Biomedical Sciences, University of Ulsan College of Medicine & Asan Institute of Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Youngsup Song
- Department of Biomedical Sciences, University of Ulsan College of Medicine & Asan Institute of Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Min-Ji Kang
- Department of Biomedical Sciences, University of Ulsan College of Medicine & Asan Institute of Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Sang-Wook Kang
- Department of Biomedical Sciences, University of Ulsan College of Medicine & Asan Institute of Life Sciences, Asan Medical Center, Seoul, Republic of Korea.
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217
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Xiao K, Zhang BY, Zhang XM, Wang J, Chen C, Chen LN, Lv Y, Shi Q, Dong XP. Re-infection of the prion from the scrapie‑infected cell line SMB-S15 in three strains of mice, CD1, C57BL/6 and Balb/c. Int J Mol Med 2016; 37:716-26. [PMID: 26820255 PMCID: PMC4771105 DOI: 10.3892/ijmm.2016.2465] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 12/23/2015] [Indexed: 11/08/2022] Open
Abstract
It is well known that the SMB-S15 cell line was originally established by cultures from the brains of mice affected by the Chandler scrapie strain, and this cell line may express PrPSc permanently. However, the infectivity of the S15-derived prions on experimental animals has not yet been well documented. In the present study, the cell lysates of SMB-S15 were intracerebrally inoculated into three different strains of mice, namely C57BL/6, Balb/c and CD1. Prion protein (PRNP) gene sequencing revealed the same encoded PrP proteins in the sequences of amino acids in the three strains of mice, in addition to a synonymous single nucleotide polymorphism (SNP) in CD1 mice. All infected mice developed typical experimental transmissible spongiform encephalopathies (TSEs) approximately six months post-infection. The clinical features of three infected mice were comparable. The pathogenic characteristics, such as the electrophoretic and glycosylation profiles and proteinase K (PK) resistance of PrPSc molecules, as well as the neuropathological characteristics, such as spongiform vacuolation, PrPSc deposits in cortex regions, astrogliosis and activated microglia, were also similar in all three strains of infected mice. However, PrPSc deposits in the cerebellums of CD1 mice were significantly fewer, which was linked with the observation that lower numbers of CD1 mice presented cerebellum-associated symptoms. Successive inoculation of the individual strains of mice with brain homogenates from the infected mice also induced typical experimental scrapie. The data in the present study thus confirm that the prion agent in SMB-S15 cells causes stable infectivity in different types of mice with distinct phenotypes after long-term propagation in vitro. The present study also provides further scrapie rodent models, which may be used in further studies.
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Affiliation(s)
- Kang Xiao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Bao-Yun Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Xiao-Mei Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Jing Wang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Cao Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Li-Na Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Yan Lv
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Qi Shi
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Xiao-Ping Dong
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases of Zhejiang University, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
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218
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Chakroun N, Hilton D, Ahmad SS, Platt GW, Dalby PA. Mapping the Aggregation Kinetics of a Therapeutic Antibody Fragment. Mol Pharm 2016; 13:307-19. [PMID: 26692229 DOI: 10.1021/acs.molpharmaceut.5b00387] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The analytical characterization of biopharmaceuticals is a fundamental step in the early stages of development and prediction of their behavior in bioprocesses. Protein aggregation in particular is a common issue as it affects all stages of product development. In the present work, we investigate the stability and the aggregation kinetics of A33Fab, a therapeutically relevant humanized antibody fragment at a wide range of pH, ionic strength, and temperature. We show that the propensity of A33Fab to aggregate under thermally accelerated conditions is pH and ionic-strength dependent with a stronger destabilizing effect of ionic strength at low pH. In the absence of added salts, A33Fab molecules appear to be protected from aggregation due to electrostatic colloidal repulsion at low pH. Analysis by transmission electron microscopy identified significantly different aggregate species formed at low and high pH. The correlations between apparent midpoints of thermal transitions (Tm,app values), or unfolded mole fractions, and aggregation rates are reported here to be significant only at the elevated incubation temperature of 65 °C, where aggregation from the unfolded state predominates. At all other conditions, particularly at 4-45 °C, aggregation of A33 Fab was predominantly from a native-like state, and the kinetics obeyed Arrhenius behavior. Despite this, the rank order of aggregation rates observed at 45 °C, 23 and 4 °C still did not correlate well to each other, indicating that forced degradation at elevated temperatures was not a good screen for predicting behavior at low temperature.
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Affiliation(s)
- Nesrine Chakroun
- EPSRC Centre for Innovative Manufacturing in Emergent Macromolecular Therapies, Department of Biochemical Engineering, University College London , London WC1H 0AH, U.K.,Department of Biochemical Engineering, University College London , London WC1H 0AH, U.K
| | - David Hilton
- EPSRC Centre for Innovative Manufacturing in Emergent Macromolecular Therapies, Department of Biochemical Engineering, University College London , London WC1H 0AH, U.K.,Department of Biochemical Engineering, University College London , London WC1H 0AH, U.K
| | - Shahina S Ahmad
- Department of Biochemical Engineering, University College London , London WC1H 0AH, U.K
| | - Geoffrey W Platt
- Unchained Laboratories, Unit 706, Avenue E West, Thorp Arch Estate, Wetherby LS23 7EG, U.K
| | - Paul A Dalby
- EPSRC Centre for Innovative Manufacturing in Emergent Macromolecular Therapies, Department of Biochemical Engineering, University College London , London WC1H 0AH, U.K.,Department of Biochemical Engineering, University College London , London WC1H 0AH, U.K
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219
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Cellular prion protein promotes post-ischemic neuronal survival, angioneurogenesis and enhances neural progenitor cell homing via proteasome inhibition. Cell Death Dis 2015; 6:e2024. [PMID: 26673668 PMCID: PMC4720898 DOI: 10.1038/cddis.2015.365] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 10/30/2015] [Accepted: 11/16/2015] [Indexed: 12/27/2022]
Abstract
Although cellular prion protein (PrPc) has been suggested to have physiological roles in neurogenesis and angiogenesis, the pathophysiological relevance of both processes remain unknown. To elucidate the role of PrPc in post-ischemic brain remodeling, we herein exposed PrPc wild type (WT), PrPc knockout (PrP−/−) and PrPc overexpressing (PrP+/+) mice to focal cerebral ischemia followed by up to 28 days reperfusion. Improved neurological recovery and sustained neuroprotection lasting over the observation period of 4 weeks were observed in ischemic PrP+/+ mice compared with WT mice. This observation was associated with increased neurogenesis and angiogenesis, whereas increased neurological deficits and brain injury were noted in ischemic PrP−/− mice. Proteasome activity and oxidative stress were increased in ischemic brain tissue of PrP−/− mice. Pharmacological proteasome inhibition reversed the exacerbation of brain injury induced by PrP−/−, indicating that proteasome inhibition mediates the neuroprotective effects of PrPc. Notably, reduced proteasome activity and oxidative stress in ischemic brain tissue of PrP+/+ mice were associated with an increased abundance of hypoxia-inducible factor 1α and PACAP-38, which are known stimulants of neural progenitor cell (NPC) migration and trafficking. To elucidate effects of PrPc on intracerebral NPC homing, we intravenously infused GFP+ NPCs in ischemic WT, PrP−/− and PrP+/+ mice, showing that brain accumulation of GFP+ NPCs was greatly reduced in PrP−/− mice, but increased in PrP+/+ animals. Our results suggest that PrPc induces post-ischemic long-term neuroprotection, neurogenesis and angiogenesis in the ischemic brain by inhibiting proteasome activity.
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220
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Newaz K, Sriram K, Bera D. Identification of Major Signaling Pathways in Prion Disease Progression Using Network Analysis. PLoS One 2015; 10:e0144389. [PMID: 26646948 PMCID: PMC4672924 DOI: 10.1371/journal.pone.0144389] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/17/2015] [Indexed: 12/27/2022] Open
Abstract
Prion diseases are transmissible neurodegenerative diseases that arise due to conformational change of normal, cellular prion protein (PrPC) to protease-resistant isofrom (rPrPSc). Deposition of misfolded PrpSc proteins leads to an alteration of many signaling pathways that includes immunological and apoptotic pathways. As a result, this culminates in the dysfunction and death of neuronal cells. Earlier works on transcriptomic studies have revealed some affected pathways, but it is not clear which is (are) the prime network pathway(s) that change during the disease progression and how these pathways are involved in crosstalks with each other from the time of incubation to clinical death. We perform network analysis on large-scale transcriptomic data of differentially expressed genes obtained from whole brain in six different mouse strain-prion strain combination models to determine the pathways involved in prion diseases, and to understand the role of crosstalks in disease propagation. We employ a notion of differential network centrality measures on protein interaction networks to identify the potential biological pathways involved. We also propose a crosstalk ranking method based on dynamic protein interaction networks to identify the core network elements involved in crosstalk with different pathways. We identify 148 DEGs (differentially expressed genes) potentially related to the prion disease progression. Functional association of the identified genes implicates a strong involvement of immunological pathways. We extract a bow-tie structure that is potentially dysregulated in prion disease. We also propose an ODE model for the bow-tie network. Predictions related to diseased condition suggests the downregulation of the core signaling elements (PI3Ks and AKTs) of the bow-tie network. In this work, we show using transcriptomic data that the neuronal dysfunction in prion disease is strongly related to the immunological pathways. We conclude that these immunological pathways occupy influential positions in the PFNs (protein functional networks) that are related to prion disease. Importantly, this functional network involvement is prevalent in all the five different mouse strain-prion strain combinations that we studied. We also conclude that the dysregulation of the core elements of the bow-tie structure, which belongs to PI3K-Akt signaling pathway, leads to dysregulation of the downstream components corresponding to other biological pathways.
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Affiliation(s)
- Khalique Newaz
- Department of Computer Science, IIIT Delhi, New Delhi, India
| | - K. Sriram
- Center for Computational Biology, IIIT Delhi, New Delhi, India
| | - Debajyoti Bera
- Department of Computer Science, IIIT Delhi, New Delhi, India
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221
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Sun J, Wang H, Chen LN, Wang J, Lv Y, Yang XD, Zhang BY, Tian C, Shi Q, Dong XP. Remarkable impairment of Wnt/β-catenin signaling in the brains of the mice infected with scrapie agents. J Neurochem 2015; 136:731-740. [PMID: 26526056 DOI: 10.1111/jnc.13416] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/02/2015] [Accepted: 10/02/2015] [Indexed: 01/06/2023]
Abstract
Prion diseases are a group of neurodegenerative diseases characterized by neuronal loss and spongiform degeneration, astrogliosis and aggregation of scrapie prion protein (PrPSc ) in the central nervous system (CNS). The Wnt signaling pathway is a highly evolutionarily conserved pathway in eukaryotes that regulates cell proliferation, differentiation and survival. Impairment of Wnt/β-catenin signaling has been reported in the CNS of various neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. To investigate the functional state of Wnt/β-catenin signaling in the CNS tissues during the progression of prion disease, the components of Wnt/β-catenin signaling in the brains of the scrapie agents 139A- and ME7-infected mice were evaluated. Compared with the normal controls, the brain levels of phosphor-β-catenin (Ser33,37 and Thr41 ) in 139A- and ME7-infected mice were significantly increased, while those of cyclin D1, which is one of the target genes of Wnt signaling, were decreased. The levels of phosphor-glycogen synthase kinase-3β (GSK-3β) Ser9 were markedly reduced, representing an enhanced GSK-3β activity in scrapie-infected mice. Both western blot and immunohistochemical assays revealed a remarkable increase of Dickkopf-1, the antagonist of Wnt/β-catenin signaling, in the brains of scrapie-infected anim-als, which co-localized well with the remaining neurons in the immunofluorescent tests. We also observed slightly decreased Wnt-3 and unchanged disheveled-3 (Dvl-3) in the brains of the infected mice. Our data, here, strongly indicate an impairment of Wnt/β-catenin pathway in the brains of prion disease, which shows a time-dependent progression along with the incubation period. Schematic for the impairment of canonical Wnt signaling during prion infection. The left and right parts represent the normal and prion-infected situations, respectively. Prion infection or PrPSc accumulation triggers the over-expression of Dickkopf WNT signaling pathway inhibitor 1 (DKK-1) and the enhancement of glycogen synthase kinase 3β (GSK-3β) activity, which subsequently promotes the phosphorylation and degradation of β-catenin. As a result, the impairment of β-catenin signaling leads to the down-regulation of Wnt target genes.
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Affiliation(s)
- Jing Sun
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Hui Wang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Department of Immunology and the key Laboratory of laboratory medicine of Jiangsu province, Jiangsu University Medical School, Zhenjiang, Jiangsu, China
| | - Li-Na Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jing Wang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yan Lv
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiao-Dong Yang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Bao-Yun Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Chan Tian
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Qi Shi
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiao-Ping Dong
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Chinese Academy of Sciences Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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222
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Wei W, Shi Q, Zhang NS, Xiao K, Chen LN, Yang XD, Ji JF, Dong XP. Expression of prion protein is closely associated with pathological and clinical progression and abnormalities of p53 in head and neck squamous cell carcinomas. Oncol Rep 2015; 35:817-24. [PMID: 26718886 DOI: 10.3892/or.2015.4425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 10/20/2015] [Indexed: 11/06/2022] Open
Abstract
Prion protein (PrP) is a glycosyl-phosphatidylinositol (GPI)-anchored membrane protein that functions as a unique pathogenic agent in transmissible spongiform encephalopathy (TSE). In the past decade, overexpression of PrP was observed in a number of human malignant tumors, such as gastric, breast and pancreatic cancer. However, the role of PrP expression in squamous cell carcinoma is rarely documented. To screen PrP expression in head and neck squamous cell carcinoma (HNSCCs), the paraffin-embedded specimens of 92 pathologically diagnosed HNSCCs were assessed by PrP-specific immunohistochemistry (IHC). A total of 55.43% (51/92) of the tested carcinoma tissues were PrP-positive. The rate of positivity and the staining intensity of PrP were closely related with the pathological degree of the HNSCCs; a higher rate of PrP expression was noted in the group of poorly differentiated cancers. PrP-positivity rates increased along with the progression of the clinical grade of the carcinomas. Further evaluation of the associations between PrP expression and the data concerning p53 abnormalities and human papillomavirus (HPV) infection in these samples as previously described, revealed that PrP-positive staining was more frequently detected in the tissues with p53-positive accumulation and the wild-type TP53 gene. The patients with a proline (Pro) polymorphism in SNP72 of TP53 showed significantly higher PrP-positive rates than those with arginine (Arg). No notable difference in PrP expression was identified between the HPV-positive and HPV-negative group. These data indicate a close association of PrP expression with clinical and histological differentiation of HNSCCs, as well as abnormalities of p53.
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Affiliation(s)
- Wei Wei
- Key Laboratory of Carcinogenesis and Translational Research (Chinese Ministry of Education), Department of Head and Neck Surgery, Peking University Cancer Hospital and Institute, Beijing 100142, P.R. China
| | - Qi Shi
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Nai-Song Zhang
- Key Laboratory of Carcinogenesis and Translational Research (Chinese Ministry of Education), Department of Head and Neck Surgery, Peking University Cancer Hospital and Institute, Beijing 100142, P.R. China
| | - Kang Xiao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Li-Na Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Xiao-Dong Yang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Jia-Fu Ji
- Key Laboratory of Carcinogenesis and Translational Research (Chinese Ministry of Education), Department of Head and Neck Surgery, Peking University Cancer Hospital and Institute, Beijing 100142, P.R. China
| | - Xiao-Ping Dong
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
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223
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Eisele YS, Monteiro C, Fearns C, Encalada SE, Wiseman RL, Powers ET, Kelly JW. Targeting protein aggregation for the treatment of degenerative diseases. Nat Rev Drug Discov 2015; 14:759-80. [PMID: 26338154 PMCID: PMC4628595 DOI: 10.1038/nrd4593] [Citation(s) in RCA: 278] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The aggregation of specific proteins is hypothesized to underlie several degenerative diseases, which are collectively known as amyloid disorders. However, the mechanistic connection between the process of protein aggregation and tissue degeneration is not yet fully understood. Here, we review current and emerging strategies to ameliorate aggregation-associated degenerative disorders, with a focus on disease-modifying strategies that prevent the formation of and/or eliminate protein aggregates. Persuasive pharmacological and genetic evidence now supports protein aggregation as the cause of postmitotic tissue dysfunction or loss. However, a more detailed understanding of the factors that trigger and sustain aggregate formation and of the structure-activity relationships underlying proteotoxicity is needed to develop future disease-modifying therapies.
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Affiliation(s)
- Yvonne S. Eisele
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Cecilia Monteiro
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Colleen Fearns
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Sandra E. Encalada
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California 92037, USA
| | - R. Luke Wiseman
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Evan T. Powers
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jeffery W. Kelly
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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224
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Kipkorir T, Tittman S, Botsios S, Manuelidis L. Highly infectious CJD particles lack prion protein but contain many viral-linked peptides by LC-MS/MS. J Cell Biochem 2015; 115:2012-21. [PMID: 24933657 PMCID: PMC7166504 DOI: 10.1002/jcb.24873] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 06/10/2014] [Indexed: 02/05/2023]
Abstract
It is widely believed that host prion protein (PrP), without nucleic acid, converts itself into an infectious form (PrP‐res) that causes transmissible encephalopathies (TSEs), such as human sporadic CJD (sCJD), endemic sheep scrapie, and epidemic BSE. There are many detailed investigations of PrP, but proteomic studies of other proteins in verified infectious TSE particles have not been pursued, even though brain homogenates without PrP retain their complete infectious titer. To define proteins that may be integral to, process, or protect an agent genome, we developed a streamlined, high‐yield purification of infectious FU‐CJD mouse brain particles with minimal PrP. Proteinase K (PK) abolished all residual particle PrP, but did not reduce infectivity, and viral‐size particles lacking PrP were ∼70S (vs. 90–120S without PK). Furthermore, over 1,500 non‐PrP proteins were still present and positively identified in high titer FU‐CJD particles without detectable PrP by mass spectrometry (LC‐MS/MS); 114 of these peptides were linked to viral motifs in the environmental–viral database, and not evident in parallel uninfected controls. Host components were also identified in both PK and non‐PK treated particles from FU‐CJD mouse brain and human sCJD brain. This abundant cellular data had several surprises, including finding Huntingtin in the sCJD but not normal human brain samples. Similarly, the neural Wiskott–Aldrich sequence and multivesicular and endosome components associated with retromer APP (Alzheimer amyloid) processing were only in sCJD. These cellular findings suggest that new therapies directed at retromer–vesicular trafficking in other neurodegenerative diseases may also counteract late‐onset sCJD PrP amyloid pathology. J. Cell. Biochem. 115: 2012–2021, 2014. © 2014 Wiley Periodicals, Inc.
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Affiliation(s)
- Terry Kipkorir
- Section of Neuropathology, Department of Surgery, Yale University Medical School, 333 Cedar St, New Haven, Connecticut, 06510
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225
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The non-octarepeat copper binding site of the prion protein is a key regulator of prion conversion. Sci Rep 2015; 5:15253. [PMID: 26482532 PMCID: PMC4651146 DOI: 10.1038/srep15253] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 09/14/2015] [Indexed: 01/01/2023] Open
Abstract
The conversion of the prion protein (PrPC) into prions plays a key
role in transmissible spongiform encephalopathies. Despite the importance for
pathogenesis, the mechanism of prion formation has escaped detailed characterization
due to the insoluble nature of prions. PrPC interacts with copper
through octarepeat and non-octarepeat binding sites. Copper coordination to the
non-octarepeat region has garnered interest due to the possibility that this
interaction may impact prion conversion. We used X-ray absorption spectroscopy to
study copper coordination at pH 5.5 and 7.0 in human PrPC constructs,
either wild-type (WT) or carrying pathological mutations. We show that mutations and
pH cause modifications of copper coordination in the non-octarepeat region. In the
WT at pH 5.5, copper is anchored to His96 and His111, while at pH 7 it is
coordinated by His111. Pathological point mutations alter the copper coordination at
acidic conditions where the metal is anchored to His111. By using in vitro
approaches, cell-based and computational techniques, we propose a model whereby
PrPC coordinating copper with one His in the non-octarepeat
region converts to prions at acidic condition. Thus, the non-octarepeat region may
act as the long-sought-after prion switch, critical for disease onset and
propagation.
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226
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Lim K, Kim SY, Lee B, Segarra C, Kang S, Ju Y, Schmerr MJ, Coste J, Kim SY, Yokoyama T, An SSA. Magnetic microparticle-based multimer detection system for the detection of prion oligomers in sheep. Int J Nanomedicine 2015; 10:241-50. [PMID: 26425091 PMCID: PMC4583538 DOI: 10.2147/ijn.s88377] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) are zoonotic fatal neurodegenerative diseases in animals and humans. TSEs are commonly known as bovine spongiform encephalopathy in cattle, scrapie in sheep and goats, chronic wasting disease in cervids, and Creutzfeldt–Jakob disease in humans. The putative transmissible agents are infectious prion proteins (PrPSc), which are formed by the conversion of the normal prion protein on the glycoprotein cell surface in the presence of other PrPSc. Reports of the transmission of TSEs through blood raised considerable concern about the safety of blood and blood products. To address this issue, many laboratories attempted to develop a sensitive and accurate blood diagnostic test to detect PrPSc. Previously, we reported that, compared to normal controls, the multimer detection system (MDS) was more efficient in detecting PrPSc in infected hamster brain homogenate, mouse plasma spiked with purified PrPSc from scrapie mouse brain, and scrapie-infected hamster plasmas. MDS differentiates prion multimers from the cellular monomer through the multimeric expression of epitopes on prion multimers, in contrast to the monomeric form. In this study, MDS detected PrPSc in plasma samples from scrapie-infected sheep expressing clinical symptoms, demonstrating 100% sensitivity and specificity in these samples. Plasma samples from asymptomatic lambs at the preclinical stage (8-month-old naturally infected offspring of scrapie-infected parents expressing a highly susceptible genotype) tested positive with 50% sensitivity and 100% specificity. In the first of two coded analyses using clinical scrapie-infected sheep and normal healthy samples, MDS successfully identified all but one of the clinical samples with 92% sensitivity and 100% specificity. Similar results were obtained in the second coded analysis using preclinical samples. MDS again successfully identified all but one of the samples with 87% sensitivity and 100% specificity. The false-negative sample was subjected to a protease pretreatment. In conclusion, MDS could accurately detect scrapie in plasma samples at both preclinical and clinical stages. From these studies, we conclude that MDS could be a promising tool for the early diagnosis of TSEs from blood samples.
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Affiliation(s)
- Kuntaek Lim
- Department of Research and Development, PeopleBio Inc., Seoul, Republic of Korea
| | - Su Yeon Kim
- Department of Arborbiology, Korean Center for Diseases and Control (KCDC), Seoul, Republic of Korea
| | - Byoungsub Lee
- Department of Research and Development, PeopleBio Inc., Seoul, Republic of Korea
| | - Christiane Segarra
- Department of Blood Screening, Etablissement Français Du Sang (EFS), Montpellier, France
| | - Sungmin Kang
- Department of Research and Development, PeopleBio Inc., Seoul, Republic of Korea
| | - Youngran Ju
- Department of Arborbiology, Korean Center for Diseases and Control (KCDC), Seoul, Republic of Korea
| | - Mary Jo Schmerr
- Ames Laboratories, US Department of Energy (USDOE), Iowa State University, Ames, IA, USA
| | - Joliette Coste
- Department of Blood Screening, Etablissement Français Du Sang (EFS), Montpellier, France
| | - Sang Yun Kim
- Department of Neurology, Seoul National University Bundang Hospital, Sungnam-si, Republic of Korea
| | - Takashi Yokoyama
- Department of Prion Research, National Institute of Animal Health, Tsukuba, Japan
| | - Seong Soo A An
- Department of Bionano Technology, Gachon University, Sungnam-si, Republic of Korea
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227
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Trafficking and degradation pathways in pathogenic conversion of prions and prion-like proteins in neurodegenerative diseases. Virus Res 2015; 207:146-54. [DOI: 10.1016/j.virusres.2015.01.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 10/01/2014] [Accepted: 01/22/2015] [Indexed: 11/20/2022]
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228
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Watts JC, Giles K, Serban A, Patel S, Oehler A, Bhardwaj S, Guan S, Greicius MD, Miller BL, DeArmond SJ, Geschwind MD, Prusiner SB. Modulation of Creutzfeldt-Jakob disease prion propagation by the A224V mutation. Ann Neurol 2015; 78:540-53. [PMID: 26094969 DOI: 10.1002/ana.24463] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 06/17/2015] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Mutations in the gene encoding the prion protein (PrP) are responsible for approximately 10 to 15% of cases of prion disease in humans, including Creutzfeldt-Jakob disease (CJD). Here, we report on the discovery of a previously unreported C-terminal PrP mutation (A224V) in a CJD patient exhibiting a disease similar to the rare VV1 subtype of sporadic (s) CJD and investigate the role of this mutation in prion replication and transmission. METHODS We generated transgenic (Tg) mice expressing human PrP with the V129 polymorphism and A224V mutation, denoted Tg(HuPrP,V129,A224V) mice, and inoculated them with different subtypes of sCJD prions. RESULTS Transmission of sCJD VV2 or MV2 prions was accelerated in Tg(HuPrP,V129,A224V) mice, compared to Tg(HuPrP,V129) mice, with incubation periods of ∼110 and ∼210 days, respectively. In contrast, sCJD MM1 prions resulted in longer incubation periods in Tg(HuPrP,V129,A224V) mice, compared to Tg(HuPrP,V129) mice (∼320 vs. ∼210 days). Prion strain fidelity was maintained in Tg(HuPrP,V129,A224V) mice inoculated with sCJD VV2 or MM1 prions, despite the altered replication kinetics. INTERPRETATION Our results suggest that A224V is a risk factor for prion disease and modulates the transmission behavior of CJD prions in a strain-specific manner, arguing that residues near the C-terminus of PrP are important for controlling the kinetics of prion replication.
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Affiliation(s)
- Joel C Watts
- Institute for Neurodegenerative Diseases.,Departments of Neurology
| | - Kurt Giles
- Institute for Neurodegenerative Diseases.,Departments of Neurology
| | - Ana Serban
- Institute for Neurodegenerative Diseases
| | | | | | | | - Shenheng Guan
- Institute for Neurodegenerative Diseases.,Pharmaceutical Chemistry
| | - Michael D Greicius
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA
| | | | | | | | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases.,Departments of Neurology.,Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA
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229
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Sneideris T, Milto K, Smirnovas V. Polymorphism of amyloid-like fibrils can be defined by the concentration of seeds. PeerJ 2015; 3:e1207. [PMID: 26355941 PMCID: PMC4563235 DOI: 10.7717/peerj.1207] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/01/2015] [Indexed: 12/11/2022] Open
Abstract
Prions are infectious proteins where the same protein may express distinct strains. The strains are enciphered by different misfolded conformations. Strain-like phenomena have also been reported in a number of other amyloid-forming proteins. One of the features of amyloid strains is the ability to self-propagate, maintaining a constant set of physical properties despite being propagated under conditions different from those that allowed initial formation of the strain. Here we report a cross-seeding experiment using strains formed under different conditions. Using high concentrations of seeds results in rapid elongation and new fibrils preserve the properties of the seeding fibrils. At low seed concentrations, secondary nucleation plays the major role and new fibrils gain properties predicted by the environment rather than the structure of the seeds. Our findings could explain conformational switching between amyloid strains observed in a wide variety of in vivo and in vitro experiments.
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Affiliation(s)
- Tomas Sneideris
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | - Katažyna Milto
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | - Vytautas Smirnovas
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
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230
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Wong SH, King CY. Amino Acid Proximities in Two Sup35 Prion Strains Revealed by Chemical Cross-linking. J Biol Chem 2015; 290:25062-71. [PMID: 26265470 DOI: 10.1074/jbc.m115.676379] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Indexed: 12/26/2022] Open
Abstract
Strains of the yeast prion [PSI] are different folding patterns of the same Sup35 protein, which stacks up periodically to form a prion fiber. Chemical cross-linking is employed here to probe different fiber structures assembled with a mutant Sup35 fragment. The photo-reactive cross-linker, p-benzoyl-l-phenylalanine (pBpa), was biosynthetically incorporated into bacterially prepared recombinant Sup(1-61)-GFP, containing the first 61 residues of Sup35, followed by the green fluorescent protein. Four methionine substitutions and two alanine substitutions were introduced at fixed positions in Sup(1-61) to allow cyanogen bromide cleavage to facilitate subsequent mass spectrometry analysis. Amyloid fibers of pBpa and Met/Ala-substituted Sup(1-61)-GFP were nucleated from purified yeast prion particles of two different strains, namely VK and VL, and shown to faithfully transmit specific strain characteristics to yeast expressing the wild type Sup35 protein. Intra- and intermolecular cross-linking were distinguished by tandem mass spectrometry analysis on fibers seeded from solutions containing equal amounts of (14)N- and (15)N-labeled protein. Fibers propagating the VL strain type exhibited intra- and intermolecular cross-linking between amino acid residues 3 and 28, as well as intra- and intermolecular linking between 32 and 55. Inter- and intramolecular cross-linking between residues 32 and 55 were detected in fibers propagating the VK strain type. Adjacencies of amino acid residues in space revealed by cross-linking were used to constrain possible chain folds of different [PSI] strains.
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Affiliation(s)
- Shenq-Huey Wong
- From the Molecular Cell Biology, Taiwan International Graduate Program, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan and the Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Chih-Yen King
- the Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
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231
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Richardson DD, Tol S, Valle-Encinas E, Pleguezuelos C, Bierings R, Geerts D, Fernandez-Borja M. The prion protein inhibits monocytic cell migration by stimulating β1 integrin adhesion and uropod formation. J Cell Sci 2015; 128:3018-29. [PMID: 26159734 DOI: 10.1242/jcs.165365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 07/03/2015] [Indexed: 02/04/2023] Open
Abstract
The broad tissue distribution and evolutionary conservation of the glycosylphosphatidylinositol (GPI)-anchored prion protein (PrP, also known as PRNP) suggests that it plays a role in cellular homeostasis. Given that integrin adhesion determines cell behavior, the proposed role of PrP in cell adhesion might underlie the various in vitro and in vivo effects associated with PrP loss-of-function, including the immune phenotypes described in PrP(-/-) mice. Here, we investigated the role of PrP in the adhesion and (transendothelial) migration of human (pro)monocytes. We found that PrP regulates β1-integrin-mediated adhesion of monocytes. Additionally, PrP controls the cell morphology and migratory behavior of monocytes: PrP-silenced cells show deficient uropod formation on immobilized VCAM and display bleb-like protrusions on the endothelium. Our data further show that PrP regulates ligand-induced integrin activation. Finally, we found that PrP controls the activation of several proteins involved in cell adhesion and migration, including RhoA and its effector cofilin, as well as proteins of the ERM family. We propose that PrP modulates β1 integrin adhesion and migration of monocytes through RhoA-induced actin remodeling mediated by cofilin, and through the regulation of ERM-mediated membrane-cytoskeleton linkage.
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Affiliation(s)
- Dion D Richardson
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066CX, The Netherlands
| | - Simon Tol
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066CX, The Netherlands
| | - Eider Valle-Encinas
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066CX, The Netherlands
| | - Cayetano Pleguezuelos
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066CX, The Netherlands
| | - Ruben Bierings
- Department of Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066CX, The Netherlands
| | - Dirk Geerts
- Department of Pediatric Oncology/Hematology, Erasmus University Medical Center, Rotterdam 3015 CN, The Netherlands
| | - Mar Fernandez-Borja
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066CX, The Netherlands
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232
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Longitudinal Detection of Prion Shedding in Saliva and Urine by Chronic Wasting Disease-Infected Deer by Real-Time Quaking-Induced Conversion. J Virol 2015; 89:9338-47. [PMID: 26136567 DOI: 10.1128/jvi.01118-15] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 06/23/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Chronic wasting disease (CWD) is an emergent, rapidly spreading prion disease of cervids. Shedding of infectious prions in saliva and urine is thought to be an important factor in CWD transmission. To help to elucidate this issue, we applied an in vitro amplification assay to determine the onset, duration, and magnitude of prion shedding in longitudinally collected saliva and urine samples from CWD-exposed white-tailed deer. We detected prion shedding as early as 3 months after CWD exposure and sustained shedding throughout the disease course. We estimated that the 50% lethal dose (LD50) for cervidized transgenic mice would be contained in 1 ml of infected deer saliva or 10 ml of urine. Given the average course of infection and daily production of these body fluids, an infected deer would shed thousands of prion infectious doses over the course of CWD infection. The direct and indirect environmental impacts of this magnitude of prion shedding on cervid and noncervid species are surely significant. IMPORTANCE Chronic wasting disease (CWD) is an emerging and uniformly fatal prion disease affecting free-ranging deer and elk and is now recognized in 22 U.S. states and 2 Canadian provinces. It is unique among prion diseases in that it is transmitted naturally through wild populations. A major hypothesis to explain CWD's florid spread is that prions are shed in excreta and transmitted via direct or indirect environmental contact. Here we use a rapid in vitro assay to show that infectious doses of CWD prions are in fact shed throughout the multiyear disease course in deer. This finding is an important advance in assessing the risks posed by shed CWD prions to animals as well as humans.
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233
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Protein misfolding occurs by slow diffusion across multiple barriers in a rough energy landscape. Proc Natl Acad Sci U S A 2015; 112:8308-13. [PMID: 26109573 DOI: 10.1073/pnas.1419197112] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The timescale for the microscopic dynamics of proteins during conformational transitions is set by the intrachain diffusion coefficient, D. Despite the central role of protein misfolding and aggregation in many diseases, it has proven challenging to measure D for these processes because of their heterogeneity. We used single-molecule force spectroscopy to overcome these challenges and determine D for misfolding of the prion protein PrP. Observing directly the misfolding of individual dimers into minimal aggregates, we reconstructed the energy landscape governing nonnative structure formation. Remarkably, rather than displaying multiple pathways, as typically expected for aggregation, PrP dimers were funneled into a thermodynamically stable misfolded state along a single pathway containing several intermediates, one of which blocked native folding. Using Kramers' rate theory, D was found to be 1,000-fold slower for misfolding than for native folding, reflecting local roughening of the misfolding landscape, likely due to increased internal friction. The slow diffusion also led to much longer transit times for barrier crossing, allowing transition paths to be observed directly for the first time to our knowledge. These results open a new window onto the microscopic mechanisms governing protein misfolding.
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234
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Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia worldwide and is an emerging global epidemic. It is characterized by an imbalance between production and clearance of amyloid β (Aβ) and tau proteins. Oligomeric forms of Aβ and tau are believed to be the most toxic. Dramatic results from AD animal models showed great promise for active and passive immune therapies targeting Aβ. However, there is very limited evidence in human studies of the clinical benefits from these approaches. Immunotherapies targeting only tau pathology have had some success but are limited so far to mouse models. The majority of current methods is based on immunological targeting of a self-protein; hence, benefits need to be balanced against risks of stimulating excessive autoimmune toxic inflammation. For greater efficacy the next generation of vaccines needs to focus more on concurrently targeting all the intermediate toxic conformers of oligomeric Aβ and tau species.
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Affiliation(s)
- Thomas Wisniewski
- Department of Neurology, Center for Cognitive Neurology, New York University School of Medicine, Alexandria ERSP, 450 East 29(th) Street, New York, NY 10016, USA; Department of Pathology, New York University School of Medicine, Alexandria ERSP, 450 East 29(th) Street, New York, NY 10016, USA; Department of Psychiatry, New York University School of Medicine, Alexandria ERSP, 450 East 29(th) Street, New York, NY 10016, USA.
| | - Fernando Goñi
- Department of Neurology, Center for Cognitive Neurology, New York University School of Medicine, Alexandria ERSP, 450 East 29(th) Street, New York, NY 10016, USA
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235
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Levine DJ, Stöhr J, Falese LE, Ollesch J, Wille H, Prusiner SB, Long JR. Mechanism of scrapie prion precipitation with phosphotungstate anions. ACS Chem Biol 2015; 10:1269-77. [PMID: 25695325 PMCID: PMC4437617 DOI: 10.1021/cb5006239] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
![]()
The phosphotungstate anion (PTA)
is widely used to facilitate the
precipitation of disease-causing prion protein (PrPSc)
from infected tissue for applications in structural studies and diagnostic
approaches. However, the mechanism of this precipitation is not understood.
In order to elucidate the nature of the PTA interaction with PrPSc under physiological conditions, solutions of PTA were characterized
by NMR spectroscopy at varying pH. At neutral pH, the parent [PW12O40]3– ion decomposes to give
a lacunary [PW11O39]7– (PW11) complex and a single orthotungstate anion [WO4]2– (WO4). To measure the efficacy of
each component of PTA, increasing concentrations of PW11, WO4, and mixtures thereof were used to precipitate PrPSc from brain homogenates of scrapie prion-infected mice. The
amount of PrPSc isolated, quantified by ELISA and immunoblotting,
revealed that both PW11 and WO4 contribute to
PrPSc precipitation. Incubation with sarkosyl, PTA, or
individual components of PTA resulted in separation of higher-density
PrP aggregates from the neuronal lipid monosialotetrahexosylganglioside
(GM1), as observed by sucrose gradient centrifugation. These experiments
revealed that yield and purity of PrPSc were greater with
polyoxometalates (POMs), which substantially supported the separation
of lipids from PrPSc in the samples. Interaction of POMs
and sarkosyl with brain homogenates promoted the formation of fibrillar
PrPSc aggregates prior to centrifugation, likely through
the separation of lipids like GM1 from PrPSc. We propose
that this separation of lipids from PrP is a major factor governing
the facile precipitation of PrPSc by PTA from tissue and
might be optimized further for the detection of prions.
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Affiliation(s)
- Dana J. Levine
- Department
of Chemistry, University of California, Berkeley, 211 Lewis Hall, Berkeley, California 94720, United States
- Institute
for Neurodegenerative Diseases, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, California 94143, United States
| | - Jan Stöhr
- Institute
for Neurodegenerative Diseases, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, California 94143, United States
- Department
of Neurology, University of California, San Francisco, 675 Nelson
Rising Lane, San Francisco, California 94143, United States
| | - Lillian E. Falese
- Institute
for Neurodegenerative Diseases, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, California 94143, United States
| | - Julian Ollesch
- Institute
for Neurodegenerative Diseases, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, California 94143, United States
| | - Holger Wille
- Institute
for Neurodegenerative Diseases, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, California 94143, United States
- Department
of Neurology, University of California, San Francisco, 675 Nelson
Rising Lane, San Francisco, California 94143, United States
| | - Stanley B. Prusiner
- Institute
for Neurodegenerative Diseases, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, California 94143, United States
- Department
of Neurology, University of California, San Francisco, 675 Nelson
Rising Lane, San Francisco, California 94143, United States
| | - Jeffrey R. Long
- Department
of Chemistry, University of California, Berkeley, 211 Lewis Hall, Berkeley, California 94720, United States
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236
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Schledorn M, Meier BH, Böckmann A. Alternative salt bridge formation in Aβ-a hallmark of early-onset Alzheimer's disease? Front Mol Biosci 2015; 2:14. [PMID: 25988181 PMCID: PMC4429654 DOI: 10.3389/fmolb.2015.00014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 04/07/2015] [Indexed: 12/21/2022] Open
Abstract
Recently the 3D structure of the Osaka mutant form (E22Δ) of Amyloid-β1-40 has been determined. We here compare the NMR chemical-shift with the published shifts of a brain-seeded form of wild-type Aβ and suggest that the determined mutant fold is accessible to the wild-type protein as well, with small conformational adaptations which accommodate the E22 residue missing in the Osaka mutant. In addition, we illustrate how other mutants could also conform to this model. The stabilization of the N-terminal part of the protein via an intermolecular salt bridge to Lys28 may represent a common structural motif for the mutants which are related to early-onset Alzheimer disease. This feature might connect to the observed increased toxicity of the mutant forms compared to wild-type Aβ1-40, where the salt bridge involving Lys28 is intramolecular.
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Affiliation(s)
- Maarten Schledorn
- Physical Chemistry, Eidgenössische Technische Hochschule Zürich Zurich, Switzerland
| | - Beat H Meier
- Physical Chemistry, Eidgenössische Technische Hochschule Zürich Zurich, Switzerland
| | - Anja Böckmann
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon Lyon, France
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237
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Kulikova AA, Makarov AA, Kozin SA. Roles of zinc ions and structural polymorphism of β-amyloid in the development of Alzheimer’s disease. Mol Biol 2015. [DOI: 10.1134/s0026893315020065] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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238
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Structural and kinetic analysis of protein-aggregate strains in vivo using binary epitope mapping. Proc Natl Acad Sci U S A 2015; 112:4489-94. [PMID: 25802384 DOI: 10.1073/pnas.1419228112] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Despite considerable progress in uncovering the molecular details of protein aggregation in vitro, the cause and mechanism of protein-aggregation disease remain poorly understood. One reason is that the amount of pathological aggregates in neural tissue is exceedingly low, precluding examination by conventional approaches. We present here a method for determination of the structure and quantity of aggregates in small tissue samples, circumventing the above problem. The method is based on binary epitope mapping using anti-peptide antibodies. We assessed the usefulness and versatility of the method in mice modeling the neurodegenerative disease amyotrophic lateral sclerosis, which accumulate intracellular aggregates of superoxide dismutase-1. Two strains of aggregates were identified with different structural architectures, molecular properties, and growth kinetics. Both were different from superoxide dismutase-1 aggregates generated in vitro under a variety of conditions. The strains, which seem kinetically under fragmentation control, are associated with different disease progressions, complying with and adding detail to the growing evidence that seeding, infectivity, and strain dependence are unifying principles of neurodegenerative disease.
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239
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Johnson CJ, Carlson CM, Morawski AR, Manthei A, Cashman NR. Assessing transmissible spongiform encephalopathy species barriers with an in vitro prion protein conversion assay. J Vis Exp 2015:52522. [PMID: 25867521 PMCID: PMC4401242 DOI: 10.3791/52522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Studies to understanding interspecies transmission of transmissible spongiform encephalopathies (TSEs, prion diseases) are challenging in that they typically rely upon lengthy and costly in vivo animal challenge studies. A number of in vitro assays have been developed to aid in measuring prion species barriers, thereby reducing animal use and providing quicker results than animal bioassays. Here, we present the protocol for a rapid in vitro prion conversion assay called the conversion efficiency ratio (CER) assay. In this assay cellular prion protein (PrPC) from an uninfected host brain is denatured at both pH 7.4 and 3.5 to produce two substrates. When the pH 7.4 substrate is incubated with TSE agent, the amount of PrPC that converts to a proteinase K (PK)-resistant state is modulated by the original host's species barrier to the TSE agent. In contrast, PrPC in the pH 3.5 substrate is misfolded by any TSE agent. By comparing the amount of PK-resistant prion protein in the two substrates, an assessment of the host's species barrier can be made. We show that the CER assay correctly predicts known prion species barriers of laboratory mice and, as an example, show some preliminary results suggesting that bobcats (Lynx rufus) may be susceptible to white-tailed deer (Odocoileus virginianus) chronic wasting disease agent.
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Affiliation(s)
| | | | - Aaron R Morawski
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health
| | - Alyson Manthei
- Merial Veterinary Scholars Program, School of Veterinary Medicine, University of Wisconsin-Madison
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240
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Requena JR, Wille H. The structure of the infectious prion protein: experimental data and molecular models. Prion 2015; 8:60-6. [PMID: 24583975 PMCID: PMC7030906 DOI: 10.4161/pri.28368] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The structures of the infectious prion protein, PrP(Sc), and that of its proteolytically truncated variant, PrP 27-30, have evaded experimental determination due to their insolubility and propensity to aggregate. Molecular modeling has been used to fill this void and to predict their structures, but various modeling approaches have produced significantly different models. The disagreement between the different modeling solutions indicates the limitations of this method. Over the years, in absence of a three-dimensional (3D) structure, a variety of experimental techniques have been used to gain insights into the structure of this biologically, medically, and agriculturally important isoform. Here, we present an overview of experimental results that were published in recent years, and which provided new insights into the molecular architecture of PrP(Sc) and PrP 27-30. Furthermore, we evaluate all published models in light of these recent, experimental data, and come to the conclusion that none of the models can accommodate all of the experimental constraints. Moreover, this conclusion constitutes an open invitation for renewed efforts to model the structure of PrP(Sc).
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241
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Shi Q, Xiao K, Zhang BY, Zhang XM, Chen LN, Chen C, Gao C, Dong XP. Successive passaging of the scrapie strains, ME7-ha and 139A-ha, generated by the interspecies transmission of mouse-adapted strains into hamsters markedly shortens the incubation times, but maintains their molecular and pathological properties. Int J Mol Med 2015; 35:1138-46. [PMID: 25683243 DOI: 10.3892/ijmm.2015.2102] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 02/10/2015] [Indexed: 11/06/2022] Open
Abstract
As a type of zoonotic disease, prion diseases may be transmitted naturally and experimentally among species. In a previous study, we demonstrated that the mouse-adapted scrapie strains, ME7 (ME7-mo) and 139A (139A-mo), can overcome the species barrier and induce experimental scrapie when inoculated into Golden hamsters and generated 2 new hamster-adapted strains, ME7 (ME7-ha) and 139A (139A-ha). In the present study, in order to assess the infectivity and other molecular and neuropathological properties of the newly formed scrapie agents, ME7-ha and 139A-ha were further intracerebrally inoculated into hamsters. Compared with infection with 1st passage strains, the incubation times and clinical courses of infection with 2nd passage strains were markedly shorter, which were quite comparable with those of the mice infected with their parent mouse strains. The glycosylation patterns of brain PrP(Sc) in the animals infected with the 2nd passage of those 2 strains maintained similar features as those in the animals infected with the 1st passage of those strains, with predominantly diglycosylated PrP(Sc). Neuropathological assays revealed comparable spongiform degeneration and microglia proliferation in the brain tissues from the infected mice and hamsters, but markedly more plaque-like deposits of PrP(Sc) and more severe astrogliosis in the brains of the hamster. These data indicate that the strains, ME7-ha 1st and 139A-ha 1st generated by interspecies infection can passage in the new host hamster and stably maintain their molecular and neuropathological characteristics.
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Affiliation(s)
- Qi Shi
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Kang Xiao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Bao-Yun Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Xiao-Mei Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Li-Na Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Cao Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Chen Gao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
| | - Xiao-Ping Dong
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, P.R. China
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242
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Subcellular distribution of the prion protein in sickness and in health. Virus Res 2015; 207:136-45. [PMID: 25683509 DOI: 10.1016/j.virusres.2015.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 02/03/2015] [Accepted: 02/03/2015] [Indexed: 11/22/2022]
Abstract
The cellular prion protein (PrP(C)) is an ubiquitously expressed glycoprotein that is most abundant in the central nervous system. It is thought to play a role in many cellular processes, including neuroprotection, but may also contribute to Alzheimer's disease and some cancers. However, it is best known for its central role in the prion diseases, such as Creutzfeldt-Jakob disease (CJD), bovine spongiform encephalopathy (BSE), and scrapie. These protein misfolding diseases can be sporadic, acquired, or genetic and are caused by refolding of endogenous PrP(C) into a beta sheet-rich, pathogenic form, PrP(Sc). Once prions are present in the central nervous system, they increase and spread during a long incubation period that is followed by a relatively short clinical disease phase, ending in death. PrP molecules can be broadly categorized as either 'good' (cellular) PrP(C) or 'bad' (scrapie prion-type) PrP(Sc), but both populations are heterogeneous and different forms of PrP(C) may influence various cellular activities. Both PrP(C) and PrP(Sc) are localized predominantly at the cell surface, with the C-terminus attached to the plasma membrane via a glycosyl-phosphatidylinositol (GPI) anchor and both can exist in cleaved forms. PrP(C) also has cytosolic and transmembrane forms, and PrP(Sc) is known to exist in a variety of conformations and aggregation states. Here, we discuss the roles of different PrP isoforms in sickness and in health, and show the subcellular distributions of several forms of PrP that are particularly relevant for PrP(C) to PrP(Sc) conversion and prion-induced pathology in the hippocampus.
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243
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Shi Q, Chen LN, Zhang BY, Xiao K, Zhou W, Chen C, Zhang XM, Tian C, Gao C, Wang J, Han J, Dong XP. Proteomics analyses for the global proteins in the brain tissues of different human prion diseases. Mol Cell Proteomics 2015; 14:854-69. [PMID: 25616867 PMCID: PMC4390265 DOI: 10.1074/mcp.m114.038018] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Indexed: 01/28/2023] Open
Abstract
Proteomics changes of brain tissues have been described in different neurodegenerative diseases including Alzheimer's disease and Parkinson's disease. However, the brain proteomics of human prion disease remains less understood. In the study, the proteomics patterns of cortex and cerebellum of brain tissues of sporadic Creutzfeldt-Jakob disease, fatal familial insomnia, and G114V genetic CJD were analyzed with isobaric tags for relative and absolute quantitation combined with multidimensional liquid chromatography and MS analysis, with the brains from three normal individuals as controls. Global protein profiling, significant pathway, and functional categories were analyzed. In total, 2287 proteins were identified with quantitative information both in cortex and cerebellum regions. Cerebellum tissues appeared to contain more up- and down-regulated proteins (727 proteins) than cortex regions (312 proteins) of Creutzfeldt-Jakob disease, fatal familial insomnia, and G114V genetic CJD. Viral myocarditis, Parkinson's disease, Alzheimer's disease, lysosome, oxidative phosphorylation, protein export, and drug metabolism-cytochrome P450 were the most commonly affected pathways of the three kinds of diseases. Almost coincident biological functions were identified in the brain tissues of the three diseases. In all, data here demonstrate that the brain tissues of Creutzfeldt-Jakob disease, fatal familial insomnia, and G114V genetic CJD have obvious proteomics changes at their terminal stages, which show the similarities not only among human prion diseases but also with other neurodegeneration diseases. This is the first study to provide a reference proteome map for human prion diseases and will be helpful for future studies focused on potential biomarkers for the diagnosis and therapy of human prion diseases.
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Affiliation(s)
- Qi Shi
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Li-Na Chen
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Bao-Yun Zhang
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Kang Xiao
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Wei Zhou
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Cao Chen
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Xiao-Mei Zhang
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Chan Tian
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Chen Gao
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Jing Wang
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Jun Han
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China
| | - Xiao-Ping Dong
- From the ‡State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University, Hangzhou 310003), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China; §Chinese Academy of Sciences Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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244
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Kanaan NM, Himmelstein DS, Ward SM, Combs B, Binder LI. Tau Protein. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00056-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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245
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Goñi F, Mathiason CK, Yim L, Wong K, Hayes-Klug J, Nalls A, Peyser D, Estevez V, Denkers N, Xu J, Osborn DA, Miller KV, Warren RJ, Brown DR, Chabalgoity JA, Hoover EA, Wisniewski T. Mucosal immunization with an attenuated Salmonella vaccine partially protects white-tailed deer from chronic wasting disease. Vaccine 2014; 33:726-33. [PMID: 25539804 DOI: 10.1016/j.vaccine.2014.11.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/13/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
Abstract
Prion disease is a unique category of illness, affecting both animals and humans, in which the underlying pathogenesis is related to a conformational change of a normal, self-protein called PrP(C) (C for cellular) to a pathological and infectious conformer known as PrP(Sc) (Sc for scrapie). Bovine spongiform encephalopathy (BSE), a prion disease believed to have arisen from feeding cattle with prion contaminated meat and bone meal products, crossed the species barrier to infect humans. Chronic wasting disease (CWD) infects large numbers of deer and elk, with the potential to infect humans. Currently no prionosis has an effective treatment. Previously, we have demonstrated we could prevent transmission of prions in a proportion of susceptible mice with a mucosal vaccine. In the current study, white-tailed deer were orally inoculated with attenuated Salmonella expressing PrP, while control deer were orally inoculated with vehicle attenuated Salmonella. Once a mucosal response was established, the vaccinated animals were boosted orally and locally by application of polymerized recombinant PrP onto the tonsils and rectal mucosa. The vaccinated and control animals were then challenged orally with CWD-infected brain homogenate. Three years post CWD oral challenge all control deer developed clinical CWD (median survival 602 days), while among the vaccinated there was a significant prolongation of the incubation period (median survival 909 days; p=0.012 by Weibull regression analysis) and one deer has remained CWD free both clinically and by RAMALT and tonsil biopsies. This negative vaccinate has the highest titers of IgA in saliva and systemic IgG against PrP. Western blots showed that immunoglobulins from this vaccinate react to PrP(CWD). We document the first partially successful vaccination for a prion disease in a species naturally at risk.
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Affiliation(s)
- Fernando Goñi
- Department of Neurology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, United States
| | - Candace K Mathiason
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
| | - Lucia Yim
- Laboratory for Vaccine Research, Department of Biotechnology, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Kinlung Wong
- Department of Neurology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, United States
| | - Jeanette Hayes-Klug
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
| | - Amy Nalls
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
| | - Daniel Peyser
- Department of Neurology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, United States
| | - Veronica Estevez
- Laboratory for Vaccine Research, Department of Biotechnology, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Nathaniel Denkers
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
| | - Jinfeng Xu
- Department of Population Health, New York University School of Medicine, 550 First Avenue, New York, NY 10016, United States
| | - David A Osborn
- Warnell School of Forestry and Natural Resources, University of Georgia, United States
| | - Karl V Miller
- Warnell School of Forestry and Natural Resources, University of Georgia, United States
| | - Robert J Warren
- Warnell School of Forestry and Natural Resources, University of Georgia, United States
| | - David R Brown
- Department of Biology and Biochemistry, University of Bath, UK
| | - Jose A Chabalgoity
- Laboratory for Vaccine Research, Department of Biotechnology, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Edward A Hoover
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
| | - Thomas Wisniewski
- Department of Neurology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, United States; Department of Pathology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, United States; Department of Psychiatry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, United States.
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246
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Liebert A, Bicknell B, Adams R. Prion Protein Signaling in the Nervous System—A Review and Perspective. ACTA ACUST UNITED AC 2014. [DOI: 10.4137/sti.s12319] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Prion protein (PrPC) was originally known as the causative agent of transmissible spongiform encephalopathy (TSE) but with recent research, its true function in cells is becoming clearer. It is known to act as a scaffolding protein, binding multiple ligands at the cell membrane and to be involved in signal transduction, passing information from the extracellular matrix (ECM) to the cytoplasm. Its role in the coordination of transmitters at the synapse, glyapse, and gap junction and in short- and long-range neurotrophic signaling gives PrPC a major part in neural transmission and nervous system signaling. It acts to regulate cellular function in multiple targets through its role as a controller of redox status and calcium ion flux. Given the importance of PrPC in cell physiology, this review considers its potential role in disease apart from TSE. The putative functions of PrPC point to involvement in neurodegenerative disease, neuropathic pain, chronic headache, and inflammatory disease including neuroinflammatory disease of the nervous system. Potential targets for the treatment of disease influenced by PrPC are discussed.
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Affiliation(s)
- Ann Liebert
- Faculty of Health Science, University of Sydney, Australia
| | - Brian Bicknell
- Faculty of Health Science, Australian Catholic University, Australia
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247
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Abstract
All aspects of biological diversification ultimately trace to evolutionary modifications at the cellular level. This central role of cells frames the basic questions as to how cells work and how cells come to be the way they are. Although these two lines of inquiry lie respectively within the traditional provenance of cell biology and evolutionary biology, a comprehensive synthesis of evolutionary and cell-biological thinking is lacking. We define evolutionary cell biology as the fusion of these two eponymous fields with the theoretical and quantitative branches of biochemistry, biophysics, and population genetics. The key goals are to develop a mechanistic understanding of general evolutionary processes, while specifically infusing cell biology with an evolutionary perspective. The full development of this interdisciplinary field has the potential to solve numerous problems in diverse areas of biology, including the degree to which selection, effectively neutral processes, historical contingencies, and/or constraints at the chemical and biophysical levels dictate patterns of variation for intracellular features. These problems can now be examined at both the within- and among-species levels, with single-cell methodologies even allowing quantification of variation within genotypes. Some results from this emerging field have already had a substantial impact on cell biology, and future findings will significantly influence applications in agriculture, medicine, environmental science, and synthetic biology.
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248
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Doolan KM, Colby DW. Conformation-dependent epitopes recognized by prion protein antibodies probed using mutational scanning and deep sequencing. J Mol Biol 2014; 427:328-40. [PMID: 25451031 DOI: 10.1016/j.jmb.2014.10.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 10/23/2014] [Accepted: 10/24/2014] [Indexed: 11/24/2022]
Abstract
Prion diseases are caused by a structural rearrangement of the cellular prion protein, PrP(C), into a disease-associated conformation, PrP(Sc), which may be distinguished from one another using conformation-specific antibodies. We used mutational scanning by cell-surface display to screen 1341 PrP single point mutants for attenuated interaction with four anti-PrP antibodies, including several with conformational specificity. Single-molecule real-time gene sequencing was used to quantify enrichment of mutants, returning 26,000 high-quality full-length reads for each screened population on average. Relative enrichment of mutants correlated to the magnitude of the change in binding affinity. Mutations that diminished binding of the antibody ICSM18 represented the core of contact residues in the published crystal structure of its complex. A similarly located binding site was identified for D18, comprising discontinuous residues in helix 1 of PrP, brought into close proximity to one another only when the alpha helix is intact. The specificity of these antibodies for the normal form of PrP likely arises from loss of this conformational feature after conversion to the disease-associated form. Intriguingly, 6H4 binding was found to depend on interaction with the same residues, among others, suggesting that its ability to recognize both forms of PrP depends on a structural rearrangement of the antigen. The application of mutational scanning and deep sequencing provides residue-level resolution of positions in the protein-protein interaction interface that are critical for binding, as well as a quantitative measure of the impact of mutations on binding affinity.
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Affiliation(s)
- Kyle M Doolan
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA
| | - David W Colby
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA.
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249
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Frequent and symmetric deposition of misfolded tau oligomers within presynaptic and postsynaptic terminals in Alzheimer's disease. Acta Neuropathol Commun 2014; 2:146. [PMID: 25330988 PMCID: PMC4209049 DOI: 10.1186/s40478-014-0146-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 07/25/2014] [Indexed: 11/10/2022] Open
Abstract
The accumulation of neurofibrillary tangles in Alzheimer’s disease (AD) propagates with characteristic spatiotemporal patterns which follow brain network connections, implying trans-synaptic transmission of tauopathy. Since misfolded tau has been shown to transmit across synapses in AD animal models, we hypothesized that synapses in AD patients may contain misfolded tau. By immunofluorescence imaging of bipartite synapses from AD subjects, we detected tau protein in 38.4% of presynaptic and 50.9% of postsynaptic terminals. The pre/post distribution for hyperphosphorylated tau was 26.9%/30.7%, and for misfolded tau 18.3%/19.3%. In the temporal cortex, microscopic aggregates of tau, containing ultra-stable oligomers, were estimated to accumulate within trillions of synapses, outnumbering macroscopic tau aggregates such as tangles by 10000 fold. Non-demented elderly also showed considerable synaptic tau hyperphosphorylation and some misfolding, implicating the synapse as one of the first subcellular compartments affected by tauopathy. Misfolding of tau protein appeared to occur in situ inside synaptic terminals, without mislocalizing or mistrafficking. Misfolded tau at synapses may represent early signs of neuronal degeneration, mediators of synaptotoxicity, and anatomical substrates for transmitting tauopathy, but its actual role in these processes remain to be elucidated.
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250
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Shott RH, Appanah C, Grenier C, Tremblay G, Roucou X, Schang LM. Development of kinomic analyses to identify dysregulated signaling pathways in cells expressing cytoplasmic PrP. Virol J 2014; 11:175. [PMID: 25280966 PMCID: PMC4283144 DOI: 10.1186/1743-422x-11-175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/26/2014] [Indexed: 12/20/2022] Open
Abstract
Background Dysregulated protein kinase signaling is involved in the pathogenesis of many chronic diseases. However, the dysregulated signaling pathways critical to prion pathogenesis remain incompletely characterized. Global analyses of signaling pathways may be useful to better characterize these pathways. We therefore set out to develop such global assays. To this end, we used as a model cytoplasmic mutants of the cellular prion protein (PrPC), which are toxic to N2a neuroblastoma cells. We tested the global assays for their sensitivity to detect changes in signaling pathways in cells expressing cytoplasmic PrP mutants. Methods We developed a targeted proteomics (kinomics) approach using multiplex Western blots to identify signaling pathways dysregulated in chronic neurological pathologies. We tested the approach for its potential ability to detect signaling changes in N2a cells expressing cytoplasmic PrP mutants. Results Multiplex Western blots were designed to quantitate the expression levels of 137 protein kinases in a single membrane and using only 1.2 mg of sample. The response of the blots was sensitive and linear to changes of 6% in protein levels. Hierarchical and functional clustering of the relative expression levels identified an mTOR signaling pathway as potentially dysregulated in N2a cells expressing cytoplasmic PrP. The mTOR signaling pathway regulates global protein synthesis, which is inhibited in cells expressing cytoplasmic PrP. The levels of proteins involved in the Akt1/p70S6K branch of mTOR signaling changed in synchrony with time of cytoplasmic PrP expression. Three kinases in this pathway, Akt, p70S6K, and eIF4B were in their inactive states, as evaluated by phosphorylation of their regulatory sites. Conclusion The results presented are consistent with the previously reported inhibition of Akt/p70S6K/eIF4B signaling as mediating pathogenesis of cytoplasmic PrP. We conclude that the kinomic analyses are sensitive and specific to detect signaling pathways dysregulated in a simple in vitro model of PrP pathogenesis. Electronic supplementary material The online version of this article (doi:10.1186/1743-422X-11-175) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Luis M Schang
- Department of Biochemistry and Centre for Prions and Protein Folding Diseases (CPPFD), University of Alberta, Edmonton, AB T6G 2E1, Canada.
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