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Abstract
Scrapie was the first prion disease to be recognised and the study of this disease in sheep and goats has provided a wealth of information not only for scrapie but also for the other prion diseases. All prion diseases are under strong genetic control of the prion gene PRNP, independent of whether they are typical or atypical scrapie and which of the different prion strains is causing infection. Decades of studies using experimental disease challenges and field surveys have established disease association models, in which species-specific amino acid variations in the prion or PrP protein, encoded by the PRNP gene, can predict disease susceptibility or resistance. PRNP genetics represents an important and successful basis for implementing scrapie eradication strategies in sheep and goats. In general terms these studies have revealed that there appear to be many more amino acid changes in PrP leading to increased resistance than to higher susceptibility. Most changes are in the globular part of PrP protein and three regions appear to have major influence. This knowledge can be transferred into prion diseases of other species to facilitate genetic control strategies. However, an obstacle remains with the lack of fully understanding the underlying molecular mechanism, impeding our ability to deal with the difference in the genetic control between typical and atypical forms of scrapie or to predict association in newly infected species. This chapter will discuss the advances in both typical and atypical scrapie from a genetic perspective.
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Affiliation(s)
- Wilfred Goldmann
- Neurobiology Division, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, United Kingdom.
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102
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Specification of Physiologic and Disease States by Distinct Proteins and Protein Conformations. Cell 2017; 171:1001-1014. [PMID: 29149602 DOI: 10.1016/j.cell.2017.10.047] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 12/15/2022]
Abstract
Protein conformational states-from intrinsically disordered ensembles to amyloids that underlie the self-templating, infectious properties of prion-like proteins-have attracted much attention. Here, we highlight the diversity, including differences in biophysical properties, that drive distinct biological functions and pathologies among self-templating proteins. Advances in chemical genomics, gene editing, and model systems now permit deconstruction of the complex interplay between these protein states and the host factors that react to them. These methods reveal that conformational switches modulate normal and abnormal information transfer and that intimate relationships exist between the intrinsic function of proteins and the deleterious consequences of their misfolding.
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103
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Sabareesan AT, Udgaonkar JB. The G126V Mutation in the Mouse Prion Protein Hinders Nucleation-Dependent Fibril Formation by Slowing Initial Fibril Growth and by Increasing the Critical Concentration. Biochemistry 2017; 56:5931-5942. [PMID: 29045139 DOI: 10.1021/acs.biochem.7b00894] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The middle disordered hydrophobic region of the prion protein plays a critical role in conformational conversion of the protein, with pathogenic as well as protective mutations being localized to this region. In particular, it has been shown that the G127V mutation in this region of the human prion protein (huPrP) is protective against the spread of prion disease, but the mechanism of protection remains unknown. In this study, quantitative analyses of the kinetics of fibril formation by wild-type mouse prion protein (moPrP) and G126V moPrP (equivalent to G127V huPrP) reveal important differences: the critical concentration is higher, the lag phase is longer, and the initial effective rate constant of fibril growth is slower for the mutant variant. The study offers a simple biophysical explanation for why the G127V mutation in huPrP would be protective in humans: the ∼5-fold increase in critical concentration caused by the mutation likely results in the critical concentration (below which fibril formation cannot occur) being higher that the concentration of the protein present in and on cells in vivo.
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Affiliation(s)
- Ambadi Thody Sabareesan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research , Bengaluru 560065, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research , Bengaluru 560065, India
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104
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Abstract
Mammalian prion proteins (PrPs) that cause transmissible spongiform encephalopathies are misfolded conformations of the host cellular PrP. The misfolded form, the scrapie PrP (PrP(Sc)), can aggregate into amyloid fibrils that progressively accumulate in the brain, evolving to a pathological phenotype. A particular characteristic of PrP(Sc) is to be found as different strains, related to the diversity of conformational states it can adopt. Prion strains are responsible for the multiple phenotypes observed in prion diseases, presenting different incubation times and diverse deposition profiles in the brain. PrP biochemical properties are also strain-dependent, such as different digestion pattern after proteolysis and different stability. Although they have long been studied, strain formation is still a major unsolved issue in prion biology. The recreation of strain-specific conformational features is of fundamental importance to study this unique pathogenic phenomenon. In our recent paper, we described that murine PrP, when expressed in bacteria, forms amyloid inclusion bodies that possess different strain-like characteristics, depending on the PrP construct. Here, we present an extra-view of these data and propose that bacteria might become a successful model to generate preparative amounts of prion strain-specific assemblies for high-resolution structural analysis as well as for addressing the determinants of infectivity and transmissibility.
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Affiliation(s)
- Bruno Macedo
- a Institut de Biotecnologia i de Biomedicina and Departament de Bioquimica i Biologia Molecular , Universitat Autonoma de Barcelona , Bellaterra ( Barcelona ), Spain ;,b Faculdade de Farmacia , Universidade Federal do Rio de Janeiro, Rio de Janeiro , Brazil
| | - Yraima Cordeiro
- b Faculdade de Farmacia , Universidade Federal do Rio de Janeiro, Rio de Janeiro , Brazil
| | - Salvador Ventura
- a Institut de Biotecnologia i de Biomedicina and Departament de Bioquimica i Biologia Molecular , Universitat Autonoma de Barcelona , Bellaterra ( Barcelona ), Spain
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105
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Nitani A, Muta H, Adachi M, So M, Sasahara K, Sakurai K, Chatani E, Naoe K, Ogi H, Hall D, Goto Y. Heparin-dependent aggregation of hen egg white lysozyme reveals two distinct mechanisms of amyloid fibrillation. J Biol Chem 2017; 292:21219-21230. [PMID: 29101231 DOI: 10.1074/jbc.m117.813097] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/19/2017] [Indexed: 01/22/2023] Open
Abstract
Heparin, a biopolymer possessing high negative charge density, is known to accelerate amyloid fibrillation by various proteins. Using hen egg white lysozyme, we studied the effects of heparin on protein aggregation at low pH, raised temperature, and applied ultrasonic irradiation, conditions under which amyloid fibrillation was promoted. Heparin exhibited complex bimodal concentration-dependent effects, either accelerating or inhibiting fibrillation at pH 2.0 and 60 °C. At concentrations lower than 20 μg/ml, heparin accelerated fibrillation through transient formation of hetero-oligomeric aggregates. Between 0.1 and 10 mg/ml, heparin rapidly induced amorphous heteroaggregation with little to no accompanying fibril formation. Above 10 mg/ml, heparin again induced fibrillation after a long lag time preceded by oligomeric aggregate formation. Compared with studies performed using monovalent and divalent anions, the results suggest two distinct mechanisms of heparin-induced fibrillation. At low heparin concentrations, initial hen egg white lysozyme cluster formation and subsequent fibrillation is promoted by counter ion binding and screening of repulsive charges. At high heparin concentrations, fibrillation is caused by a combination of salting out and macromolecular crowding effects probably independent of protein net charge. Both fibrillation mechanisms compete against amorphous aggregation, producing a complex heparin concentration-dependent phase diagram. Moreover, the results suggest an active role for amorphous oligomeric aggregates in triggering fibrillation, whereby breakdown of supersaturation takes place through heterogeneous nucleation of amyloid on amorphous aggregates.
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Affiliation(s)
- Ayame Nitani
- From the Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Hiroya Muta
- From the Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Masayuki Adachi
- From the Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Masatomo So
- From the Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Kenji Sasahara
- From the Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Kazumasa Sakurai
- Institute of Advanced Technology, Kindai University, 930 Nishimitani, Kinokawa, Wakayama 649-6493, Japan
| | - Eri Chatani
- Department of Chemistry, Graduate School of Science, Kobe University, Hyogo 657-8501, Japan
| | - Kazumitsu Naoe
- National Institute of Technology, Nara College, Nara 639-1080, Japan
| | - Hirotsugu Ogi
- Graduate School of Engineering, Suita, Osaka 565-0871, Japan, and
| | - Damien Hall
- From the Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.,Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Yuji Goto
- From the Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan,
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106
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Miguelez-Rodriguez A, Santos-Juanes J, Vicente-Etxenausia I, Perez de Heredia-Goñi K, Garcia B, Quiros LM, Lorente-Gea L, Guerra-Merino I, Aguirre JJ, Fernandez-Vega I. Brains with sporadic Creutzfeldt-Jakob disease and copathology showed a prolonged end-stage of disease. J Clin Pathol 2017; 71:446-450. [PMID: 29097599 DOI: 10.1136/jclinpath-2017-204794] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/16/2017] [Accepted: 10/18/2017] [Indexed: 01/28/2023]
Abstract
AIMS To investigate the expression of major proteins related to primary neurodegenerative diseases and their prognostic significance in brains with Creutzfeldt-Jakob disease (CJD). MATERIALS AND METHODS Thirty consecutive cases of confirmed CJD during the period 2010-2015 at Basque Brain bank were retrospectively reviewed. Moreover, major neurodegenerative-associated proteins (phosphorylated Tau, 4R tau, 3R tau, alpha-synuclein, TDP43, amyloid beta) were tested. Clinical data were reviewed. Cases were divided according to the presence or absence of copathology. Survival curves were also determined. RESULTS Copathology was significantly associated with survival in brains with CJD (4.2±1.2 vs 9.2±1.9; P=0.019) and in brains with MM1/MV1 CJD (2.1±1.0 vs 6.7±2.8; P=0.012). Besides, the presence of more than one major neurodegenerative-associated protein was significantly associated with survival (4.2±1.2 vs 10.7±2.6; P=0.017). Thus, univariate analyses further pointed out variables significantly associated with better survival: copathology in CJD (HR=0.430; P=0.033); more than one neurodegenerative-associated protein in CJD (HR=0.369; P=0.036) and copathology in MM1/MV1 CJD (HR=0.525; P=0.032). CONCLUSION The existence of copathology significantly prolongs survival in patients with rapidly progressive dementia due to CJD. The study of major neurodegenerative-associated proteins in brains with CJD could allow us to further understand the molecular mechanisms behind prion diseases.
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Affiliation(s)
| | - Jorge Santos-Juanes
- Department of Pathology, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Ikerne Vicente-Etxenausia
- Biobanco Vasco para la Investigación (O+eHun), Brain Bank, Hospital Universitario Araba, Vitoria-Gasteiz, Spain
| | - Katty Perez de Heredia-Goñi
- Biobanco Vasco para la Investigación (O+eHun), Brain Bank, Hospital Universitario Araba, Vitoria-Gasteiz, Spain
| | - Beatriz Garcia
- Scientific Department, Instituto Universitario Fernández-Vega, Oviedo, Spain
| | - Luis M Quiros
- Scientific Department, Instituto Universitario Fernández-Vega, Oviedo, Spain.,Department of Functional Biology, University of Oviedo, Oviedo, Spain
| | - Laura Lorente-Gea
- Department of Pathology, Hospital Universitario de Araba-Txagorritxu, Vitoria-Gasteiz, Spain
| | - Isabel Guerra-Merino
- Faculty of Medicine, University of Basque Country, Vitoria, Spain.,Biobanco Vasco para la Investigación (O+eHun), Brain Bank, Hospital Universitario Araba, Vitoria-Gasteiz, Spain.,Department of Pathology, Hospital Universitario de Araba-Txagorritxu, Vitoria-Gasteiz, Spain
| | - Jose J Aguirre
- Department of Pathology, Hospital Universitario de Araba-Txagorritxu, Vitoria-Gasteiz, Spain
| | - Ivan Fernandez-Vega
- Department of Pathology, Hospital Universitario Central de Asturias, Oviedo, Spain.,Biobanco Vasco para la Investigación (O+eHun), Brain Bank, Hospital Universitario Araba, Vitoria-Gasteiz, Spain.,Scientific Department, Instituto Universitario Fernández-Vega, Oviedo, Spain.,Department of Pathology, Hospital Universitario de Araba-Txagorritxu, Vitoria-Gasteiz, Spain
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107
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Ke PC, Sani MA, Ding F, Kakinen A, Javed I, Separovic F, Davis TP, Mezzenga R. Implications of peptide assemblies in amyloid diseases. Chem Soc Rev 2017; 46:6492-6531. [PMID: 28702523 PMCID: PMC5902192 DOI: 10.1039/c7cs00372b] [Citation(s) in RCA: 239] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Neurodegenerative disorders and type 2 diabetes are global epidemics compromising the quality of life of millions worldwide, with profound social and economic implications. Despite the significant differences in pathology - much of which are poorly understood - these diseases are commonly characterized by the presence of cross-β amyloid fibrils as well as the loss of neuronal or pancreatic β-cells. In this review, we document research progress on the molecular and mesoscopic self-assembly of amyloid-beta, alpha synuclein, human islet amyloid polypeptide and prions, the peptides and proteins associated with Alzheimer's, Parkinson's, type 2 diabetes and prion diseases. In addition, we discuss the toxicities of these amyloid proteins based on their self-assembly as well as their interactions with membranes, metal ions, small molecules and engineered nanoparticles. Through this presentation we show the remarkable similarities and differences in the structural transitions of the amyloid proteins through primary and secondary nucleation, the common evolution from disordered monomers to alpha-helices and then to β-sheets when the proteins encounter the cell membrane, and, the consensus (with a few exceptions) that off-pathway oligomers, rather than amyloid fibrils, are the toxic species regardless of the pathogenic protein sequence or physicochemical properties. In addition, we highlight the crucial role of molecular self-assembly in eliciting the biological and pathological consequences of the amyloid proteins within the context of their cellular environments and their spreading between cells and organs. Exploiting such structure-function-toxicity relationship may prove pivotal for the detection and mitigation of amyloid diseases.
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Affiliation(s)
- Pu Chun Ke
- ARC Center of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Marc-Antonie Sani
- School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Rd, Parkville, VIC 3010, Australia
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Aleksandr Kakinen
- ARC Center of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Ibrahim Javed
- ARC Center of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Rd, Parkville, VIC 3010, Australia
| | - Thomas P. Davis
- ARC Center of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Department of Chemistry, University of Warwick, Gibbet Hill, Coventry, CV4 7AL, United Kingdom
| | - Raffaele Mezzenga
- ETH Zurich, Department of Health Science & Technology, Schmelzbergstrasse 9, LFO, E23, 8092 Zurich, Switzerland
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108
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Bamdad K. Sequence-dependent dynamical instability of the human prion protein: a comparative simulation study. J Biomol Struct Dyn 2017; 36:3023-3033. [PMID: 28868991 DOI: 10.1080/07391102.2017.1375430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The present study aimed to explore the most probable regions of the human prion protein backbone for which the initial steps of conformational transitions as a result of intrinsic and extrinsic perturbing factors on the protein structure can be assigned. A total of 0.3-μs molecular dynamics simulations on several analog structures of the protein have been performed. To mimic the impact of the extrinsic and intrinsic destructive parameters on the dynamical characteristics of the protein, mild acidic conditions and R208H mutation have been simulated. The findings indicated that distribution of conformational flexibilities along the protein chain was almost independent of the induced perturbing factors, and was mostly centralized on certain distinct parts of the structure comprising residues 132-145 and 187-203. Analyses also revealed that the segment comprising residues 187-203 may be considered as a peptide sequence, possessing high potential to start the initial steps of conformational rearrangements due to the induced physicochemical alterations. Sequence alignment and molecular dynamics data also revealed that segment 178-203 prefers to accommodate in extended structures rather than α-helices. Region 178-203 may be considered as a peptide switch capable of initiating the conformational transitions due to the introduced modifications and perturbing parameters.
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Affiliation(s)
- Kourosh Bamdad
- a Department of Biology, Faculty of Science , Payame Noor University (PNU) , 19395-3697 , Iran
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109
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β-Amyloid and the Pathomechanisms of Alzheimer's Disease: A Comprehensive View. Molecules 2017; 22:molecules22101692. [PMID: 28994715 PMCID: PMC6151811 DOI: 10.3390/molecules22101692] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/02/2017] [Accepted: 10/06/2017] [Indexed: 01/14/2023] Open
Abstract
Protein dyshomeostasis is the common mechanism of neurodegenerative diseases such as Alzheimer’s disease (AD). Aging is the key risk factor, as the capacity of the proteostasis network declines during aging. Different cellular stress conditions result in the up-regulation of the neurotrophic, neuroprotective amyloid precursor protein (APP). Enzymatic processing of APP may result in formation of toxic Aβ aggregates (β-amyloids). Protein folding is the basis of life and death. Intracellular Aβ affects the function of subcellular organelles by disturbing the endoplasmic reticulum-mitochondria cross-talk and causing severe Ca2+-dysregulation and lipid dyshomeostasis. The extensive and complex network of proteostasis declines during aging and is not able to maintain the balance between production and disposal of proteins. The effectivity of cellular pathways that safeguard cells against proteotoxic stress (molecular chaperones, aggresomes, the ubiquitin-proteasome system, autophagy) declines with age. Chronic cerebral hypoperfusion causes dysfunction of the blood-brain barrier (BBB), and thus the Aβ-clearance from brain-to-blood decreases. Microglia-mediated clearance of Aβ also declines, Aβ accumulates in the brain and causes neuroinflammation. Recognition of the above mentioned complex pathogenesis pathway resulted in novel drug targets in AD research.
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110
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Koeller KK, Shih RY. Viral and Prion Infections of the Central Nervous System: Radiologic-Pathologic Correlation: From the Radiologic Pathology Archives. Radiographics 2017; 37:199-233. [PMID: 28076019 DOI: 10.1148/rg.2017160149] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Viral infections of the central nervous system (CNS) range in clinical severity, with the most severe proving fatal within a matter of days. Some of the more than 100 different viruses known to affect the brain and spinal cord are neurotropic with a predilection for producing CNS infection. The host response to viral infection of the CNS is responsible for the pathophysiology and imaging findings seen in affected patients. Viral CNS infections can take the form of meningitis, encephalitis, encephalomyelitis, or, when involving the spinal cord and nerve roots, encephalomyeloradiculitis. In 1982, an infectious particle termed a prion that lacked nucleic acid and therefore was not a virus was reported to produce the fatal neurodegenerative disease Creutzfeldt-Jakob disease and related disorders. These prion diseases produce characteristic neuroimaging findings that are distinct from those seen in most viral infections. The clinical and imaging findings associated with viral CNS infection are often nonspecific, with microbiologic analysis of cerebrospinal fluid the most useful single test allowing for diagnosis of a specific viral infection. This review details the spectrum of viral CNS infections and uses case material from the archives of the American Institute for Radiologic Pathology, with a focus on the specific clinical characteristics and magnetic resonance imaging features seen in these infections. Where possible, the imaging features that allow distinction of these infections from other CNS inflammatory conditions are highlighted.
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Affiliation(s)
- Kelly K Koeller
- From the Department of Neuroradiology, American Institute for Radiologic Pathology, Silver Spring, Md (K.K.K., R.Y.S.); Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (K.K.K.); Uniformed Services University of the Health Sciences, Bethesda, Md (R.Y.S.); and Department of Radiology, Walter Reed National Military Medical Center, Bethesda, Md (R.Y.S.)
| | - Robert Y Shih
- From the Department of Neuroradiology, American Institute for Radiologic Pathology, Silver Spring, Md (K.K.K., R.Y.S.); Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (K.K.K.); Uniformed Services University of the Health Sciences, Bethesda, Md (R.Y.S.); and Department of Radiology, Walter Reed National Military Medical Center, Bethesda, Md (R.Y.S.)
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111
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Fast C, Goldmann W, Berthon P, Tauscher K, Andréoletti O, Lantier I, Rossignol C, Bossers A, Jacobs JG, Hunter N, Groschup MH, Lantier F, Langeveld JPM. Protecting effect of PrP codons M142 and K222 in goats orally challenged with bovine spongiform encephalopathy prions. Vet Res 2017; 48:52. [PMID: 28927447 PMCID: PMC5606029 DOI: 10.1186/s13567-017-0455-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/19/2017] [Indexed: 12/31/2022] Open
Abstract
Breeding towards genetic resistance to prion disease is effective in eliminating scrapie. In sheep, classical forms of scrapie have been eradicated almost completely in several countries by breeding programs using a prion protein (PrP) gene (PRNP) amino acid polymorphism. For goats, field and experimental studies have provided evidence for several amino acid polymorphisms that are associated with resistance to scrapie, but only limited data are available concerning the susceptibility of caprine PRNP genotypes to BSE. In this study, goat kids representing five PRNP genotypes based on three polymorphisms (M142, Q211 and K222 and the wild type I142, R211 and Q222) were orally challenged with bovine or goat BSE. Wild type goats were killed with clinical signs between 24-28 months post inoculation (mpi) to both challenges, and goats with genotype R/Q211 succumbed between 29-36 mpi. I/M142 goats developed clinical signs at 44-45 mpi and M/M142 goats remained healthy until euthanasia at 48 mpi. None of the Q/K222 goats showed definite clinical signs. Taken together the highest attack ratios were seen in wild type and R/Q211 goats, and the lowest in I/M142, M/M142 and Q/K222. In all genotype groups, one or more goats remained healthy within the incubation period in both challenges and without detectable PrP deposition in the tissues. Our data show that both the K222 and M142 polymorphisms lengthen the incubation period significantly compared to wild type animals, but only K222 was associated with a significant increase in resistance to BSE infection after oral exposure to both BSE sources.
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Affiliation(s)
- C. Fast
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, Greifswald-Insel Riems, Germany
| | - W. Goldmann
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - P. Berthon
- UMR 1282 ISP, Institut National de la Recherche Agronomique (INRA), University of Tours, 37380 Nouzilly, France
| | - K. Tauscher
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, Greifswald-Insel Riems, Germany
| | - O. Andréoletti
- INRA, UMR 1225, Interactions Hôtes Agents Pathogènes, Ecole Nationale Vétérinaire de Toulouse, Toulouse Cedex, France
| | - I. Lantier
- UMR 1282 ISP, Institut National de la Recherche Agronomique (INRA), University of Tours, 37380 Nouzilly, France
| | - C. Rossignol
- UMR 1282 ISP, Institut National de la Recherche Agronomique (INRA), University of Tours, 37380 Nouzilly, France
| | - A. Bossers
- Wageningen BioVeterinary Research, Wageningen University & Research, Houtribweg 39, 8221RA Lelystad, The Netherlands
| | - J. G. Jacobs
- Wageningen BioVeterinary Research, Wageningen University & Research, Houtribweg 39, 8221RA Lelystad, The Netherlands
| | - N. Hunter
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - M. H. Groschup
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, Greifswald-Insel Riems, Germany
| | - F. Lantier
- UMR 1282 ISP, Institut National de la Recherche Agronomique (INRA), University of Tours, 37380 Nouzilly, France
| | - J. P. M. Langeveld
- Wageningen BioVeterinary Research, Wageningen University & Research, Houtribweg 39, 8221RA Lelystad, The Netherlands
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112
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Igel-Egalon A, Moudjou M, Martin D, Busley A, Knäpple T, Herzog L, Reine F, Lepejova N, Richard CA, Béringue V, Rezaei H. Reversible unfolding of infectious prion assemblies reveals the existence of an oligomeric elementary brick. PLoS Pathog 2017; 13:e1006557. [PMID: 28880932 PMCID: PMC5589264 DOI: 10.1371/journal.ppat.1006557] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/28/2017] [Indexed: 11/20/2022] Open
Abstract
Mammalian prions, the pathogens that cause transmissible spongiform encephalopathies, propagate by self-perpetuating the structural information stored in the abnormally folded, aggregated conformer (PrPSc) of the host-encoded prion protein (PrPC). To date, no structural model related to prion assembly organization satisfactorily describes how strain-specified structural information is encoded and by which mechanism this information is transferred to PrPC. To achieve progress on this issue, we correlated the PrPSc quaternary structural transition from three distinct prion strains during unfolding and refolding with their templating activity. We reveal the existence of a mesoscopic organization in PrPSc through the packing of a highly stable oligomeric elementary subunit (suPrP), in which the strain structural determinant (SSD) is encoded. Once kinetically trapped, this elementary subunit reversibly loses all replicative information. We demonstrate that acquisition of the templating interface and infectivity requires structural rearrangement of suPrP, in concert with its condensation. The existence of such an elementary brick scales down the SSD support to a small oligomer and provide a basis of reflexion for prion templating process and propagation. Prions are self-propagating assemblies with all necessary and sufficient replicative information stored in the 3D structure of the misfolded form of PrP called PrPSc. Since the emergence of the prion theory in the 80s, many attempts have been done to identify prion replicative information at molecular scale. Different models have been constructed based on a broad panel of experimental observations and some of them predict the existence of periodic elements constituting prion assemblies. Here, by using partial unfolding approaches, we trapped an oligomeric conformer that we called suPrP, which could constitute the elementary brick of prion assemblies. Once isolated, this elementary brick is devoid of infectivity. However, it becomes infectious once condensated into larger assemblies. The identification of the elementary PrP building block provides a new structural basis for understanding prion replicative information storage and spreading.
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Affiliation(s)
- Angélique Igel-Egalon
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Mohammed Moudjou
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Davy Martin
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Alexandra Busley
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Tina Knäpple
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Laetitia Herzog
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Fabienne Reine
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Nad’a Lepejova
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Charles-Adrien Richard
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
| | - Vincent Béringue
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
- * E-mail: (VB); (HR)
| | - Human Rezaei
- INRA, Université Paris-Saclay, UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France
- * E-mail: (VB); (HR)
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113
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Marín-Moreno A, Fernández-Borges N, Espinosa JC, Andréoletti O, Torres JM. Transmission and Replication of Prions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:181-201. [PMID: 28838661 DOI: 10.1016/bs.pmbts.2017.06.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transmissible spongiform encephalopathies (TSEs) are a group of progressive, invariably fatal diseases that affect the nervous system of many mammals including humans. The key molecular event in the pathogenesis of TSEs is the conversion of the cellular prion protein PrPC into a disease-associated isoform PrPSc. The "protein-only hypothesis" argues that PrPSc itself is the infectious agent. In effect, PrPSc can adopt several structures that represent different prion strains. The interspecies transmission of TSEs is difficult because of differences between the host and donor primary PrP sequence. However, transmission is not impossible as this occurred when bovine spongiform encephalopathy spread to humans causing variant Creutzfeldt-Jakob disease (vCJD). This event determined a need for a thorough understanding of prion replication and transmission so that we could be one step ahead of further threats for human health. This chapter focuses on these concepts and on new insights gained into prion propagation mechanisms.
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Affiliation(s)
| | | | - Juan C Espinosa
- Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, Spain
| | - Olivier Andréoletti
- UMR INRA-ENVT 1225, Interactions Hôte Agent Pathogène, Ecole Nationale Vétérinaire de Toulouse, Toulouse, France
| | - Juan M Torres
- Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, Spain.
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114
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Bistaffa E, Rossi M, De Luca CMG, Moda F. Biosafety of Prions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:455-485. [PMID: 28838674 DOI: 10.1016/bs.pmbts.2017.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Prions are the infectious agents that cause devastating and untreatable disorders known as Transmissible Spongiform Encephalopathies (TSEs). The pathologic events and the infectious nature of these transmissible agents are not completely understood yet. Due to the difficulties in inactivating prions, working with them requires specific recommendations and precautions. Moreover, with the advent of innovative technologies, such as the Protein Misfolding Cyclic Amplification (PMCA) and the Real Time Quaking-Induced Conversion (RT-QuIC), prions could be amplified in vitro and the infectious features of the amplified products need to be carefully assessed.
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Affiliation(s)
- Edoardo Bistaffa
- IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy; Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Martina Rossi
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Chiara M G De Luca
- IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy; Università degli Studi di Pavia, Pavia, Italy
| | - Fabio Moda
- IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy.
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115
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Fehlinger A, Wolf H, Hossinger A, Duernberger Y, Pleschka C, Riemschoss K, Liu S, Bester R, Paulsen L, Priola SA, Groschup MH, Schätzl HM, Vorberg IM. Prion strains depend on different endocytic routes for productive infection. Sci Rep 2017; 7:6923. [PMID: 28761068 PMCID: PMC5537368 DOI: 10.1038/s41598-017-07260-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/27/2017] [Indexed: 01/08/2023] Open
Abstract
Prions are unconventional agents composed of misfolded prion protein that cause fatal neurodegenerative diseases in mammals. Prion strains induce specific neuropathological changes in selected brain areas. The mechanism of strain-specific cell tropism is unknown. We hypothesised that prion strains rely on different endocytic routes to invade and replicate within their target cells. Using prion permissive cells, we determined how impairment of endocytosis affects productive infection by prion strains 22L and RML. We demonstrate that early and late stages of prion infection are differentially sensitive to perturbation of clathrin- and caveolin-mediated endocytosis. Manipulation of canonical endocytic pathways only slightly influenced prion uptake. However, blocking the same routes had drastic strain-specific consequences on the establishment of infection. Our data argue that prion strains use different endocytic pathways for infection and suggest that cell type-dependent differences in prion uptake could contribute to host cell tropism.
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Affiliation(s)
- Andrea Fehlinger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Hanna Wolf
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - André Hossinger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Yvonne Duernberger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Catharina Pleschka
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Katrin Riemschoss
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Shu Liu
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Romina Bester
- Institut für Virologie, Technische Universität München, Trogerstr. 30, 81675, München, Germany
| | - Lydia Paulsen
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Suzette A Priola
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT, 59840, USA
| | - Martin H Groschup
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, 17493, Greifswald-Insel Riems, Germany
| | - Hermann M Schätzl
- Dept. of Comparative Biology & Experimental Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Ina M Vorberg
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany. .,Department of Neurology, Rheinische Friedrich-Wilhelms-Universität, 53127, Bonn, Germany.
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116
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Legname G, Moda F. The Prion Concept and Synthetic Prions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:147-156. [PMID: 28838659 DOI: 10.1016/bs.pmbts.2017.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
Transmissible spongiform encephalopathies or prion diseases are a group of fatal neurodegenerative diseases caused by unconventional infectious agents, known as prions (PrPSc). Prions derive from a conformational conversion of the normally folded prion protein (PrPC), which acquires pathological and infectious features. Moreover, PrPSc is able to transmit the pathological conformation to PrPC through a mechanism that is still not well understood. The generation of synthetic prions, which behave like natural prions, is of fundamental importance to study the process of PrPC conversion and to assess the efficacy of therapeutic strategies to interfere with this process. Moreover, the ability of synthetic prions to induce pathology in animals confirms that the pathological properties of the prion strains are all enciphered in abnormal conformations, characterizing these infectious agents.
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Affiliation(s)
- Giuseppe Legname
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
| | - Fabio Moda
- IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy.
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117
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Plummer IH, Wright SD, Johnson CJ, Pedersen JA, Samuel MD. Temporal patterns of chronic wasting disease prion excretion in three cervid species. J Gen Virol 2017; 98:1932-1942. [PMID: 28708047 DOI: 10.1099/jgv.0.000845] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chronic wasting disease (CWD) is the only naturally occurring transmissible spongiform encephalopathy affecting free-ranging wildlife populations. Transmission of CWD occurs by direct contact or through contaminated environments; however, little is known about the temporal patterns of CWD prion excretion and shedding in wild cervids. We tested the urine and faeces of three species of captive cervids (elk, mule and white-tailed deer) at 6, 12, 18 and 24 months after oral inoculation to evaluate the temporal, species- and genotype-specific factors affecting the excretion of CWD prions. Although none of the animals exhibited clinical signs of CWD during the study, we determined that all three cervid species were excreting CWD prions by 6 months post-inoculation. Faecal samples were consistently positive for CWD prions for all three cervid species (88 %), and were more likely to be positive than urine samples (28 %). Cervids with genotypes encoding for the prion protein (PRNP) that were considered to be more susceptible to CWD were more likely to excrete CWD prions (94 %) than cervids with genotypes considered to be less susceptible (64 %). All cervids with CWD prions in their urine also had positive faeces (n=5), but the converse was not true. Our study is the first to demonstrate CWD prion excretion in urine by asymptomatic elk and mule deer. Our results indicate that the excretion of CWD prions in faeces and, to a lesser extent, urine may provide an important avenue for depositing prions in the environment.
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Affiliation(s)
- Ian H Plummer
- Department of Forest and Wildlife Ecology, University of Wisconsin - Madison, 1630 Linden Drive, Madison, WI 53706, USA
| | - Scott D Wright
- US Geological Survey, National Wildlife Health Center, 6006 Schroeder Road, Madison, Wisconsin 53711, USA.,Present address: 4730 Toepfer Road, Middleton, Wisconsin 53562, USA
| | - Chad J Johnson
- Departments of Soil Science, Civil and Environmental Engineering, and Chemistry, University of Wisconsin - Madison, 1525 Observatory Drive, Madison, Wisconsin 53706, USA
| | - Joel A Pedersen
- Departments of Soil Science, Civil and Environmental Engineering, and Chemistry, University of Wisconsin - Madison, 1525 Observatory Drive, Madison, Wisconsin 53706, USA
| | - Michael D Samuel
- Retired, US Geological Survey, Wisconsin Cooperative Wildlife Research Unit, University of Wisconsin - Madison, 204 Russell Labs, 1630 Linden Drive, Madison, WI 53706, USA
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118
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Senesi M, Lewis V, Kim JH, Adlard PA, Finkelstein DI, Collins SJ. In vivo prion models and the disconnection between transmissibility and neurotoxicity. Ageing Res Rev 2017; 36:156-164. [PMID: 28450269 DOI: 10.1016/j.arr.2017.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Revised: 02/03/2017] [Accepted: 03/17/2017] [Indexed: 02/01/2023]
Abstract
The primary causative event in the development of prion diseases is the misfolding of the normal prion protein (PrPC) into an ensemble of altered conformers (herein collectively denoted as PrPSc) that accumulate in the brain. Prominent amongst currently unresolved key aspects underpinning prion disease pathogenesis is whether transmission and toxicity are sub-served by different molecular species of PrPSc, which may directly impact on the development of effective targeted treatments. The use of murine models of prion disease has been of fundamental importance for probing the relationship between hypothesised "neurotoxic" and "transmissible" PrPSc and the associated kinetic profiles of their production during disease evolution, but unfortunately consensus has not been achieved. Recent in vivo studies have led to formulation of the "two-phase" hypothesis, which postulates that there is first an exponential increase in transmitting PrPSc species followed by an abrupt transition to propagation of neurotoxic PrPSc species. Such observations however, appear inconsistent with previous in vivo murine studies employing detailed time-course behavioural testing, wherein evidence of neurotoxicity could be detected early in disease progression. This review analyses the contributions of in vivo murine models attempting to provide insights into the relationship between transmitting and neurotoxic PrPSc species and explores possible refinements to the "two-phase hypothesis", that better accommodate the available historical and recent evidence.
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Affiliation(s)
- Matteo Senesi
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville 3010, Australia
| | - Victoria Lewis
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville 3010, Australia
| | - Jee H Kim
- The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville 3010, Australia
| | - Paul A Adlard
- The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville 3010, Australia
| | - David I Finkelstein
- The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville 3010, Australia
| | - Steven J Collins
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville 3010, Australia; The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville 3010, Australia.
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119
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Wemheuer WM, Wrede A, Schulz-Schaeffer WJ. Types and Strains: Their Essential Role in Understanding Protein Aggregation in Neurodegenerative Diseases. Front Aging Neurosci 2017; 9:187. [PMID: 28670273 PMCID: PMC5472693 DOI: 10.3389/fnagi.2017.00187] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/26/2017] [Indexed: 11/21/2022] Open
Abstract
Protein misfolding and aggregation is a key event in diseases like Alzheimer’s disease (AD) or Parkinson’s disease (PD) and is associated with neurodegeneration. Factors that initiate protein misfolding and the role of protein aggregation in the pathophysiology of disease pose major challenges to the neuroscientific community. Interestingly, although the accumulation of the same misfolded protein, e.g., α-synuclein is detectable in all idiopathic PD patients, the disease spectrum covers a variety of different clinical presentations and disease courses. In a more recent attempt this clinical variance is being explained in analogy to prion diseases by different protein aggregate conformations. In prion diseases a relationship between protein aggregate conformation properties and the clinical disease course was shown by relating different prion types to a dementia and an ataxic disease course in Creutzfeldt-Jakob patients. This principle is currently transferred to AD, PD and other neurodegenerative diseases with protein aggregation. However, differences in protein aggregate conformation are frequently addressed as disease strains. The term “strain” also derives from prion research and evolved by adopting the virus terminology at a time when transmissible spongiform encephalopathies (TSEs; later called prion diseases) were assumed to be caused by a virus. The problem is that in virus taxonomy the term “type” refers to properties of the disease agent itself and the term “strain” refers to host associated factors that interact with the disease agent and may moderately modify the clinical disease presentation. Strain factors can be discovered only after transmission and passaging of the agent in a host of a different species. The incorrect use of the terminology confuses disease agent and host factors and hampers the understanding of the pathophysiology of protein aggregate-associated neurodegenerative diseases. In this review article the discoveries are reviewed that explain how the terms “type” and “strain” emerged for unconventional disease agents. This may help to avoid confusion in the terminology of protein aggregation diseases and to reflect correctly the impact of protein aggregate conformation as well as host factor contribution on different clinical variations of AD, PD and other neurodegenerative diseases.
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Affiliation(s)
- Wiebke M Wemheuer
- Institute of Neuropathology, Saarland University Medical CenterHomburg, Germany.,Luxembourg Centre of Systems Biology, University of LuxembourgEsch-sur-Alzette, Luxembourg
| | - Arne Wrede
- Institute of Neuropathology, Saarland University Medical CenterHomburg, Germany.,Prion and Dementia Research Unit, Institute of Neuropathology, University Medical Center GoettingenGoettingen, Germany
| | - Walter J Schulz-Schaeffer
- Institute of Neuropathology, Saarland University Medical CenterHomburg, Germany.,Prion and Dementia Research Unit, Institute of Neuropathology, University Medical Center GoettingenGoettingen, Germany
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120
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Fernandez-Funez P, Sanchez-Garcia J, Rincon-Limas DE. Drosophila models of prionopathies: insight into prion protein function, transmission, and neurotoxicity. Curr Opin Genet Dev 2017; 44:141-148. [PMID: 28415023 PMCID: PMC5474952 DOI: 10.1016/j.gde.2017.03.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/03/2017] [Accepted: 03/21/2017] [Indexed: 11/26/2022]
Abstract
Prion diseases (PrD) are unique neurodegenerative conditions with sporadic, genetic, and infectious etiologies. The agent responsible for these pathologies is a misfolded conformation of the prion protein (PrP). Although a process of autocatalytic "conversion" is known to mediate disease transmission, important gaps still remain regarding the physiological function of PrP and its relevance to pathogenesis, the molecular and cellular mechanisms mediating neurotoxicity and transmission, and the PrP conformations responsible for neurotoxicity. New Drosophila models expressing mammalian PrP have revealed physiological insight into PrP function and opened the door to significant progress in prion transmission and PrP neurotoxicity. Importantly, flies expressing human PrP showing a robust eye phenotype will allow performing genetic screens to uncover novel mechanisms mediating PrP neurotoxicity.
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Affiliation(s)
- Pedro Fernandez-Funez
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN 55811, USA.
| | - Jonatan Sanchez-Garcia
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Diego E Rincon-Limas
- Departments of Neurology and Neuroscience, McKnight Brain Institute and Center for Translational Research on Neurodegenerative Diseases, University of Florida, Gainesville, FL 32611, USA
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121
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Sengupta I, Bhate SH, Das R, Udgaonkar JB. Salt-Mediated Oligomerization of the Mouse Prion Protein Monitored by Real-Time NMR. J Mol Biol 2017; 429:1852-1872. [DOI: 10.1016/j.jmb.2017.05.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/05/2017] [Accepted: 05/07/2017] [Indexed: 12/11/2022]
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122
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Malevanets A, Chong PA, Hansen DF, Rizk P, Sun Y, Lin H, Muhandiram R, Chakrabartty A, Kay LE, Forman-Kay JD, Wodak SJ. Interplay of buried histidine protonation and protein stability in prion misfolding. Sci Rep 2017; 7:882. [PMID: 28408762 PMCID: PMC5429843 DOI: 10.1038/s41598-017-00954-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/20/2017] [Indexed: 12/03/2022] Open
Abstract
Misofolding of mammalian prion proteins (PrP) is believed to be the cause of a group of rare and fatal neurodegenerative diseases. Despite intense scrutiny however, the mechanism of the misfolding reaction remains unclear. We perform nuclear Magnetic Resonance and thermodynamic stability measurements on the C-terminal domains (residues 90–231) of two PrP variants exhibiting different pH-induced susceptibilities to aggregation: the susceptible hamster prion (GHaPrP) and its less susceptible rabbit homolog (RaPrP). The pKa of histidines in these domains are determined from titration experiments, and proton-exchange rates are measured at pH 5 and pH 7. A single buried highly conserved histidine, H187/H186 in GHaPrP/RaPrP, exhibited a markedly down shifted pKa ~5 for both proteins. However, noticeably larger pH-induced shifts in exchange rates occur for GHaPrP versus RaPrP. Analysis of the data indicates that protonation of the buried histidine destabilizes both PrP variants, but produces a more drastic effect in the less stable GHaPrP. This interpretation is supported by urea denaturation experiments performed on both PrP variants at neutral and low pH, and correlates with the difference in disease susceptibility of the two species, as expected from the documented linkage between destabilization of the folded state and formation of misfolded and aggregated species.
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Affiliation(s)
- Anatoly Malevanets
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada
| | - P Andrew Chong
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - D Flemming Hansen
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,University College London, Division of Biosciences, London, WC1E 6BT, UK
| | - Paul Rizk
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Yulong Sun
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
| | - Hong Lin
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada
| | - Ranjith Muhandiram
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Avi Chakrabartty
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
| | - Lewis E Kay
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada
| | - Julie D Forman-Kay
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| | - Shoshana J Wodak
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,VIB Structural Biology Research Center, VUB, Pleinlaan 2, 1050, Brussels, Belgium.
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123
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Prion-like characteristics of the bacterial protein Microcin E492. Sci Rep 2017; 7:45720. [PMID: 28361921 PMCID: PMC5374632 DOI: 10.1038/srep45720] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 03/02/2017] [Indexed: 11/10/2022] Open
Abstract
Microcin E492 (Mcc) is a pore-forming bacteriotoxin. Mcc activity is inhibited at the stationary phase by formation of amyloid-like aggregates in the culture. Here we report that, in a similar manner as prions, Mcc naturally exists as two conformers: a β-sheet-rich, protease-resistant, aggregated, inactive form (Mccia), and a soluble, protease-sensitive, active form (Mcca). The exogenous addition of culture medium containing Mccia or purified in vitro-generated Mccia into the culture induces the rapid and efficient conversion of Mcca into Mccia, which is maintained indefinitely after passaging, changing the bacterial phenotype. Mccia prion-like activity is conformation-dependent and could be reduced by immunodepleting Mccia. Interestingly, an internal region of Mcc shares sequence similarity with the central domain of the prion protein, which is key to the formation of mammalian prions. A synthetic peptide spanning this sequence forms amyloid-like fibrils in vitro and is capable of inducing the conversion of Mcca into Mcciain vivo, suggesting that this region corresponds to the prion domain of Mcc. Our findings suggest that Mcc is the first prokaryotic protein with prion properties which harnesses prion-like transmission to regulate protein function, suggesting that propagation of biological information using a prion-based conformational switch is an evolutionary conserved mechanism.
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124
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Hagiwara K, Iwamaru Y, Tabeta N, Yokoyama T, Tobiume M. Evaluation of rapid post-mortem test kits for bovine spongiform encephalopathy (BSE) screening in Japan: Their analytical sensitivity to atypical BSE prions. Prion 2017; 11:113-127. [PMID: 28358272 DOI: 10.1080/19336896.2017.1300731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
A classical type of bovine spongiform encephalopathy (C-BSE), recognized in 1987, had a large impact on public health due to its zoonotic link to variant Creutzfeldt-Jakob disease by the human consumption of dietary products contaminated with the C-BSE prion. Thus, a number of countries implemented BSE surveillance using rapid post-mortem test kits that were approved for detection of the C-BSE prion in the cattle brain. However, as atypical BSE (L- and H-BSE) cases emerged in subsequent years, the efficacy of the kits for the detection of atypical BSE prions became a matter of concern. In response to this, laboratories in the European Union and Canada evaluated the kits used in their countries. Here, we carried out an evaluation study of NippiBL®, a kit currently used for BSE screening in Japan. By applying the kit to cattle brains of field cases of C-BSE and L-BSE, and an experimental case of H-BSE, we showed its comparable sensitivities to C, L-, and H-BSE prions, and satisfactory performance required by the European Food Safety Authority. In addition to NippiBL®, two kits (TeSeE® and FRELISA®) formerly used in Japan were effective for detection of the L-BSE prion, although the two kits were unable to be tested for the H-BSE prion due to the discontinuation of domestic sales during this study. These results indicate that BSE screening in Japan is as effective as those in other countries, and it is unlikely that cases of atypical BSE have been overlooked.
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Affiliation(s)
- Ken'ichi Hagiwara
- a Department of Biochemistry and Cell Biology , National Institute of Infectious Diseases , Shinjuku-ku , Tokyo , Japan
| | - Yoshifumi Iwamaru
- b Prion Disease Research Unit , National Institute of Animal Health , Tsukuba City , Ibaraki , Japan
| | - Naoko Tabeta
- b Prion Disease Research Unit , National Institute of Animal Health , Tsukuba City , Ibaraki , Japan
| | - Takashi Yokoyama
- b Prion Disease Research Unit , National Institute of Animal Health , Tsukuba City , Ibaraki , Japan
| | - Minoru Tobiume
- c Department of Pathology , National Institute of Infectious Diseases , Shinjuku-ku , Tokyo , Japan
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125
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Abstract
Prion diseases, like Alzheimer's disease and Parkinson disease, are rapidly progressive neurodegenerative disorders caused by misfolding followed by aggregation and accumulation of protein deposits in neuronal cells. Here we measure intramolecular polypeptide backbone reconfiguration as a way to understand the molecular basis of prion aggregation. Our hypothesis is that when reconfiguration is either much faster or much slower than bimolecular diffusion, biomolecular association is not stable, but as the reconfiguration rate becomes similar to the rate of biomolecular diffusion, the association is more stable and subsequent aggregation is faster. Using the technique of Trp-Cys contact quenching, we investigate the effects of various conditions on reconfiguration dynamics of the Syrian hamster and rabbit prion proteins. This protein exhibits behavior in all three reconfiguration regimes. We conclude that the hamster prion is prone to aggregation at pH 4.4 because its reconfiguration rate is slow enough to expose hydrophobic residues on the same time scale that bimolecular association occurs, whereas the rabbit sequence avoids aggregation by reconfiguring 10 times faster than the hamster sequence.
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126
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Pathology of Animal Transmissible Spongiform Encephalopathies (TSEs). Food Saf (Tokyo) 2017; 5:1-9. [PMID: 32231922 DOI: 10.14252/foodsafetyfscj.2016027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 11/24/2016] [Indexed: 11/21/2022] Open
Abstract
Pathology is the study of the structural and functional changes produced by diseases or - more specifically - the lesions they cause. To achieve this pathologists employ various approaches. These include description of lesions that are visible to the naked eye which are the subject of anatomic pathology and changes at the cellular level that are visible under the microscope, the subject of histopathology. Changes at the molecular level which are identified by probes that target specific molecules - mainly proteins that are detected using immunohistochemistry (IHC). As transmissible spongiform encephalopathies (TSEs) do not cause visible lesions anatomic pathology is not applicable to their study. For decades the application of histopathology to detect vacuoles or plaques was the only means of confirming TSE disease. The subsequent discovery of the cellular prion protein (PrPC) and its pathogenic isoform, PrPSc, which is a ubiquitous marker of TSEs, led to the production of anti-PrP antibodies, and enabled the development of PrPSc detection techniques such as immunohistochemistry, Histoblot and PET-blot that have evolved in parallel with similar biochemical methods such as Western blot and ELISA. These methods offer greater sensitivity than histopathology in TSE diagnosis and crucially they can be applied to analyze various phenotypic aspects of single TSE sources increasing the amount of data and offering higher discriminatory power. The above principles are applied to diagnose and define TSE phenotypes which form the basis of strain characterisation.
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127
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Brandner S, Jaunmuktane Z. Prion disease: experimental models and reality. Acta Neuropathol 2017; 133:197-222. [PMID: 28084518 PMCID: PMC5250673 DOI: 10.1007/s00401-017-1670-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/04/2017] [Accepted: 01/05/2017] [Indexed: 01/04/2023]
Abstract
The understanding of the pathogenesis and mechanisms of diseases requires a multidisciplinary approach, involving clinical observation, correlation to pathological processes, and modelling of disease mechanisms. It is an inherent challenge, and arguably impossible to generate model systems that can faithfully recapitulate all aspects of human disease. It is, therefore, important to be aware of the potentials and also the limitations of specific model systems. Model systems are usually designed to recapitulate only specific aspects of the disease, such as a pathological phenotype, a pathomechanism, or to test a hypothesis. Here, we evaluate and discuss model systems that were generated to understand clinical, pathological, genetic, biochemical, and epidemiological aspects of prion diseases. Whilst clinical research and studies on human tissue are an essential component of prion research, much of the understanding of the mechanisms governing transmission, replication, and toxicity comes from in vitro and in vivo studies. As with other neurodegenerative diseases caused by protein misfolding, the pathogenesis of prion disease is complex, full of conundra and contradictions. We will give here a historical overview of the use of models of prion disease, how they have evolved alongside the scientific questions, and how advancements in technologies have pushed the boundaries of our understanding of prion biology.
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Affiliation(s)
- Sebastian Brandner
- Department of Neurodegenerative Disease, UCL Institute of Neurology and Division of Neuropathology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, Queen Square, London, WC1N 3BG UK
| | - Zane Jaunmuktane
- Department of Neurodegenerative Disease, UCL Institute of Neurology and Division of Neuropathology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, Queen Square, London, WC1N 3BG UK
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128
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The role of extracellular vesicles in neurodegenerative diseases. Biochem Biophys Res Commun 2017; 483:1178-1186. [DOI: 10.1016/j.bbrc.2016.09.090] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 09/08/2016] [Accepted: 09/18/2016] [Indexed: 01/09/2023]
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129
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Falcão CBR, Lima ILDMNF, Duarte JMB, de Oliveira JRM, Torres RA, Wanderley AM, Gomes da Cunha JE, Garcia JE. Are Brazilian cervids at risk of prion diseases? Prion 2017; 11:65-70. [PMID: 28281927 PMCID: PMC5360121 DOI: 10.1080/19336896.2016.1274000] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 10/20/2022] Open
Abstract
Prion diseases are neurodegenerative fatal disorders that affect human and non-human mammals. Chronic Wasting Disease (CWD) is a prion disease of cervids regarded as a public health problem in North America, and polymorphisms at specific codons in the PRNP gene are associated with this disease. To assess the potential CWD susceptibility of South American free-ranging deer, the presence of these polymorphisms was examined in Mazama gouazoubira, Ozotoceros bezoarticus and Blastocerus dichotomus. Despite the lack of CWD reports in Brazil, the examined codons (95, 96, 116, 132, 225, and 226) of the PRNP gene showed potential CWD susceptibility in Brazilian deer. Low abundancy of deer in Brazil possibly difficult both CWD proliferation and detection, however, CWD surveillance may not be neglected.
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Affiliation(s)
- Caio Bruno Ribeiro Falcão
- Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brazil;
| | | | | | | | | | - Artur Maia Wanderley
- Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brazil;
| | | | - José Eduardo Garcia
- Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brazil;
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130
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Transmissible Spongiform Encephalopathies of Humans and Animals. Infect Dis (Lond) 2017. [DOI: 10.1016/b978-0-7020-6285-8.00023-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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131
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Kashchiev D. Modeling the Effect of Monomer Conformational Change on the Early Stage of Protein Self-Assembly into Fibrils. J Phys Chem B 2016; 121:35-46. [PMID: 28029261 DOI: 10.1021/acs.jpcb.6b09302] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Filamentous self-assembly of proteins is an important process implicated in a plethora of human diseases and of interest for nanotechnology. Using rate equations, we analyze the early stage of the process in solutions that initially contain fibrillation-passive protein monomers and in which the nascent fibrils are practically insoluble. The analysis is based on a model accounting for the conformational and/or other changes the passive monomers experience to transform themselves into fibrillation-active monomers and thus become fibril nuclei. The model allows exact, comprehensive, and simple mathematical description of the early stage of fibrillation, which reveals the usually neglected role of the nucleation nonstationarity in this stage of fibrillation. We obtain exact and user-friendly expressions for experimentally accessible quantities such as the size distribution of fibrils, their number and mass concentrations, the rate and nonstationary period of fibril nucleation, and the delay time of fibril formation. Analyzing available experimental data, we find that the theory successfully describes the fibrillation time course of pathological and nonpathological ataxin-3, a protein involved in the neurodegenerative disorder spinocerebellar ataxia type-3. The analysis provides mechanistic insight into the reason for the higher fibril nucleation and elongation rates of the pathological ataxin-3.
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Affiliation(s)
- Dimo Kashchiev
- Institute of Physical Chemistry, Bulgarian Academy of Sciences , ul. Acad. G. Bonchev 11, Sofia 1113, Bulgaria
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132
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Abstract
Since the term protein was first coined in 1838 and protein was discovered to be the essential component of fibrin and albumin, all cellular proteins were presumed to play beneficial roles in plants and mammals. However, in 1967, Griffith proposed that proteins could be infectious pathogens and postulated their involvement in scrapie, a universally fatal transmissible spongiform encephalopathy in goats and sheep. Nevertheless, this novel hypothesis had not been evidenced until 1982, when Prusiner and coworkers purified infectious particles from scrapie-infected hamster brains and demonstrated that they consisted of a specific protein that he called a "prion." Unprecedentedly, the infectious prion pathogen is actually derived from its endogenous cellular form in the central nervous system. Unlike other infectious agents, such as bacteria, viruses, and fungi, prions do not contain genetic materials such as DNA or RNA. The unique traits and genetic information of prions are believed to be encoded within the conformational structure and posttranslational modifications of the proteins. Remarkably, prion-like behavior has been recently observed in other cellular proteins-not only in pathogenic roles but also serving physiological functions. The significance of these fascinating developments in prion biology is far beyond the scope of a single cellular protein and its related disease.
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133
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Riek R, Eisenberg DS. The activities of amyloids from a structural perspective. Nature 2016; 539:227-235. [PMID: 27830791 DOI: 10.1038/nature20416] [Citation(s) in RCA: 326] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/14/2016] [Indexed: 12/16/2022]
Abstract
The aggregation of proteins into structures known as amyloids is observed in many neurodegenerative diseases, including Alzheimer's disease. Amyloids are composed of pairs of tightly interacting, many stranded and repetitive intermolecular β-sheets, which form the cross-β-sheet structure. This structure enables amyloids to grow by recruitment of the same protein and its repetition can transform a weak biological activity into a potent one through cooperativity and avidity. Amyloids therefore have the potential to self-replicate and can adapt to the environment, yielding cell-to-cell transmissibility, prion infectivity and toxicity.
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Affiliation(s)
- Roland Riek
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zürich, Switzerland
| | - David S Eisenberg
- UCLA-DOE Institute, Los Angeles, California 90095-1570, USA.,Howard Hughes Medical Institute, Los Angeles, California 90095-1570, USA
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134
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Collinge J. Mammalian prions and their wider relevance in neurodegenerative diseases. Nature 2016; 539:217-226. [PMID: 27830781 DOI: 10.1038/nature20415] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/09/2016] [Indexed: 02/07/2023]
Abstract
Prions are notorious protein-only infectious agents that cause invariably fatal brain diseases following silent incubation periods that can span a lifetime. These diseases can arise spontaneously, through infection or be inherited. Remarkably, prions are composed of self-propagating assemblies of a misfolded cellular protein that encode information, generate neurotoxicity and evolve and adapt in vivo. Although parallels have been drawn with Alzheimer's disease and other neurodegenerative conditions involving the deposition of assemblies of misfolded proteins in the brain, insights are now being provided into the usefulness and limitations of prion analogies and their aetiological and therapeutic relevance.
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Affiliation(s)
- John Collinge
- Medical Research Council Prion Unit, University College London Institute of Neurology, London WC1N 3BG, UK.,Department of Neurodegenerative Disease, University College London Institute of Neurology, London WC1N 3BG, UK
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135
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Luk C, Jones S, Thomas C, Fox NC, Mok TH, Mead S, Collinge J, Jackson GS. Diagnosing Sporadic Creutzfeldt-Jakob Disease by the Detection of Abnormal Prion Protein in Patient Urine. JAMA Neurol 2016; 73:1454-1460. [PMID: 27699415 PMCID: PMC5701732 DOI: 10.1001/jamaneurol.2016.3733] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
IMPORTANCE Creutzfeldt-Jakob disease (CJD) is a fatal neurodegenerative disorder associated with the accumulation of infectious abnormal prion protein through a mechanism of templated misfolding. A recent report has described the detection of abnormal prion protein in the urine of patients with variant CJD (vCJD) using protein misfolding by cyclic amplification, which was apparently absent in the more common sporadic form of CJD (sCJD). A noninvasive diagnostic test could improve early diagnosis of sCJD and, by screening donations, mitigate the potential risks of prion transmission through human urine-derived pharmaceuticals. Here, we describe the adaptation of the direct detection assay, developed originally as a blood test for vCJD, for the detection of disease-associated prion protein in urine samples from patients with sCJD. OBJECTIVE To determine the feasibility of sCJD diagnosis by adaptation of an established vCJD diagnostic blood test to urine. DESIGN, SETTING, AND PARTICIPANTS This retrospective, cross-sectional study included anonymized urine samples from healthy nonneurological control individuals (n = 91), patients with non-prion neurodegenerative diseases (n = 34), and patients with prion disease (n = 37) of which 20 had sCJD. Urine samples obtained during the Medical Research Council PRION-1 Trial, the National Prion Monitoring Cohort Study, and/or referred to the National Prion Clinic or Dementia Research Centre at the National Hospital for Neurology and Neurosurgery in the United Kingdom. MAIN OUTCOMES AND MEASURES Presence of sCJD infection determined by an assay that captures, enriches, and detects disease-associated prion protein isoforms. RESULTS A total of 162 samples were analyzed, composed of 91 normal control individuals (51 male, 33 female, and 7 not recorded), 34 neurological disease control individuals (19 male and 15 female), and 37 with prion disease (22 male and 15 female). The assay's specificity for prion disease was 100% (95% CI, 97%-100%), with no false-positive reactions from 125 control individuals, including 34 from a range of neurodegenerative diseases. In contrast to a previous study, which used a different method, sensitivity to vCJD infection was low (7.7%; 95% CI, 0.2%-36%), with only 1 of 13 patients with positive test results, while sensitivity to sCJD was unexpectedly high at 40% (95% CI, 19%-64%). CONCLUSIONS AND RELEVANCE We determined 40% of sCJD urine sample results as positive. To our knowledge, this is the first demonstration of an assay that can detect sCJD infection in urine or any target analyte outside of the central nervous system. Urine detection could allow the development of rapid, molecular diagnostics for sCJD and has implications for other neurodegenerative diseases where disease-related assemblies of misfolded proteins might also be present in urine.
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Affiliation(s)
- Connie Luk
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Samantha Jones
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Claire Thomas
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Nick C Fox
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Tze H Mok
- National Prion Clinic, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, Queen Square, London WC1N 3BG, UK
| | - Simon Mead
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
- National Prion Clinic, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, Queen Square, London WC1N 3BG, UK
| | - John Collinge
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
- National Prion Clinic, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, Queen Square, London WC1N 3BG, UK
| | - Graham S Jackson
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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136
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Howitt J, Hill AF. Exosomes in the Pathology of Neurodegenerative Diseases. J Biol Chem 2016; 291:26589-26597. [PMID: 27852825 DOI: 10.1074/jbc.r116.757955] [Citation(s) in RCA: 181] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
More than 30 years ago, two unexpected findings were discovered that challenged conventional thinking in biology. The first was the identification of a misfolded protein with transmissible properties associated with a group of neurodegenerative diseases known as transmissible spongiform encephalopathies. The second was the discovery of a new pathway used for the extracellular release of biomolecules, including extracellular vesicles called exosomes. Two decades later, the convergence of these pathways was shown when exosomes were found to play a significant role in both the transmission and propagation of protein aggregates in disease. Recent research has now revealed that the majority of proteins involved in neurodegenerative diseases are transported in exosomes, and that external stresses due to age-related impairment of protein quality control mechanisms can promote the transcellular flux of these proteins in exosomes. Significantly, exosomes provide an environment that can induce the conformational conversion of native proteins into aggregates that can be transmitted to otherwise aggregate-free cells in the brain. Here we review the current roles of exosomes in the pathology of neurodegenerative diseases.
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Affiliation(s)
- Jason Howitt
- From the Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010 and
| | - Andrew F Hill
- the Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
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137
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MacLea KS. What Makes a Prion: Infectious Proteins From Animals to Yeast. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 329:227-276. [PMID: 28109329 DOI: 10.1016/bs.ircmb.2016.08.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
While philosophers in ancient times had many ideas for the cause of contagion, the modern study of infective agents began with Fracastoro's 1546 proposal that invisible "spores" spread infectious disease. However, firm categorization of the pathogens of the natural world would need to await a mature germ theory that would not arise for 300 years. In the 19th century, the earliest pathogens described were bacteria and other cellular microbes. By the close of that century, the work of Ivanovsky and Beijerinck introduced the concept of a virus, an infective particle smaller than any known cell. Extending into the early-mid-20th century there was an explosive growth in pathogenic microbiology, with a cellular or viral cause identified for nearly every transmissible disease. A few occult pathogens remained to be discovered, including the infectious proteins (prions) proposed by Prusiner in 1982. This review discusses the prions identified in mammals, yeasts, and other organisms, focusing on the amyloid-based prions. I discuss the essential biochemical properties of these agents and the application of this knowledge to diseases of protein misfolding and aggregation, as well as the utility of yeast as a model organism to study prion and amyloid proteins that affect human and animal health. Further, I summarize the ideas emerging out of these studies that the prion concept may go beyond proteinaceous infectious particles and that prions may be a subset of proteins having general nucleating or seeding functions involved in noninfectious as well as infectious pathogenic protein aggregation.
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Affiliation(s)
- K S MacLea
- University of New Hampshire, Manchester, NH, United States.
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138
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Wu EL, Qi Y, Park S, Mallajosyula SS, MacKerell AD, Klauda JB, Im W. Insight into Early-Stage Unfolding of GPI-Anchored Human Prion Protein. Biophys J 2016; 109:2090-100. [PMID: 26588568 DOI: 10.1016/j.bpj.2015.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/04/2015] [Accepted: 10/08/2015] [Indexed: 11/29/2022] Open
Abstract
Prion diseases are fatal neurodegenerative disorders, which are characterized by the accumulation of misfolded prion protein (PrPSc) converted from a normal host cellular prion protein (PrPC). Experimental studies suggest that PrPC is enriched with α-helical structure, whereas PrPSc contains a high proportion of β-sheet. In this study, we report the impact of N-glycosylation and the membrane on the secondary structure stability utilizing extensive microsecond molecular dynamics simulations. Our results reveal that the HB (residues 173 to 194) C-terminal fragment undergoes conformational changes and helix unfolding in the absence of membrane environments because of the competition between protein backbone intramolecular and protein-water intermolecular hydrogen bonds as well as its intrinsic instability originated from the amino acid sequence. This initiation of the unfolding process of PrPC leads to a subsequent increase in the length of the HB-HC loop (residues 195 to 199) that may trigger larger rigid body motions or further unfolding around this region. Continuous interactions between prion protein and the membrane not only constrain the protein conformation but also decrease the solvent accessibility of the backbone atoms, thereby stabilizing the secondary structure, which is enhanced by N-glycosylation via additional interactions between the N-glycans and the membrane surface.
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Affiliation(s)
- Emilia L Wu
- Department of Molecular Biosciences and Center for Bioinformatics, The University of Kansas, Lawrence, Kansas
| | - Yifei Qi
- Department of Molecular Biosciences and Center for Bioinformatics, The University of Kansas, Lawrence, Kansas
| | - Soohyung Park
- Department of Molecular Biosciences and Center for Bioinformatics, The University of Kansas, Lawrence, Kansas
| | - Sairam S Mallajosyula
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland; Department of Chemistry, Indian Institute of Technology Gandhinagar, Chandkheda, Ahmedabad, Gujarat, India
| | - Alexander D MacKerell
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Chandkheda, Ahmedabad, Gujarat, India
| | - Jeffery B Klauda
- Department of Chemical and Biomolecular Engineering and the Biophysics Program, The University of Maryland, College Park, Maryland
| | - Wonpil Im
- Department of Molecular Biosciences and Center for Bioinformatics, The University of Kansas, Lawrence, Kansas.
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139
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Abstract
Yeast and fungal prions are infectious proteins, most being self-propagating amyloids of normally soluble proteins. Their effects range from a very mild detriment to lethal, with specific effects dependent on the prion protein and the specific prion variant ("prion strain"). The prion amyloids of Sup35p, Ure2p, and Rnq1p are in-register, parallel, folded β-sheets, an architecture that naturally suggests a mechanism by which a protein can template its conformation, just as DNA or RNA templates its sequence. Prion propagation is critically affected by an array of chaperone systems, most notably the Hsp104/Hsp70/Hsp40 combination, which is responsible for generating new prion seeds from old filaments. The Btn2/Cur1 antiprion system cures most [URE3] prions that develop, and the Ssb antiprion system blocks [PSI+] generation.
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Affiliation(s)
- Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0830
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140
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Eraña H, Venegas V, Moreno J, Castilla J. Prion-like disorders and Transmissible Spongiform Encephalopathies: An overview of the mechanistic features that are shared by the various disease-related misfolded proteins. Biochem Biophys Res Commun 2016; 483:1125-1136. [PMID: 27590581 DOI: 10.1016/j.bbrc.2016.08.166] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/04/2016] [Accepted: 08/29/2016] [Indexed: 02/06/2023]
Abstract
Prion diseases or Transmissible Spongiform Encephalopathies (TSEs) are a group of fatal neurodegenerative disorders affecting several mammalian species. Its causative agent, disease-associated prion protein (PrPd), is a self-propagating β-sheet rich aberrant conformation of the cellular prion protein (PrPC) with neurotoxic and aggregation-prone properties, capable of inducing misfolding of PrPC molecules. PrPd is the major constituent of prions and, most importantly, is the first known example of a protein with infectious attributes. It has been suggested that similar molecular mechanisms could be shared by other proteins implicated in diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis or systemic amyloidoses. Accordingly, several terms have been proposed to collectively group all these disorders. Through the stringent evaluation of those aspects that characterise TSE-causing prions, in particular propagation and spread, strain variability or transmissibility, we will discuss whether terms such as "prion", "prion-like", "prionoid" or "propagon" can be used when referring to the aetiological agents of the above other disorders. Moreover, it will also be discussed whether the term "infectious", which defines a prion essential trait, is currently misused when referring to the other misfolded proteins.
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Affiliation(s)
- Hasier Eraña
- CIC bioGUNE, Parque Tecnológico de Bizkaia, 48160, Derio, Spain
| | - Vanesa Venegas
- CIC bioGUNE, Parque Tecnológico de Bizkaia, 48160, Derio, Spain
| | - Jorge Moreno
- CIC bioGUNE, Parque Tecnológico de Bizkaia, 48160, Derio, Spain
| | - Joaquín Castilla
- CIC bioGUNE, Parque Tecnológico de Bizkaia, 48160, Derio, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, 48011, Bizkaia, Spain.
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141
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Peggion C, Bertoli A, Sorgato MC. Almost a century of prion protein(s): From pathology to physiology, and back to pathology. Biochem Biophys Res Commun 2016; 483:1148-1155. [PMID: 27581199 DOI: 10.1016/j.bbrc.2016.07.118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 07/27/2016] [Indexed: 12/30/2022]
Abstract
Prions are one of the few pathogens whose name is renowned at all population levels, after the dramatic years pervaded by the fear of eating prion-infected food. If now this, somehow irrational, scare of bovine meat inexorably transmitting devastating brain disorders is largely subdued, several prion-related issues are still unsolved, precluding the design of therapeutic approaches that could slow, if not halt, prion diseases. One unsolved issue is, for example, the role of the prion protein (PrPC), whole conformational misfolding originates the prion but whose physiologic reason d'etre in neurons, and in cells at large, remains enigmatic. Preceded by a historical outline, the present review will discuss the functional pleiotropicity ascribed to PrPC, and whether this aspect could fall, at least in part, into a more concise framework. It will also be devoted to radically different perspectives for PrPC, which have been recently brought to the attention of the scientific world with unexpected force. Finally, it will discuss the possible reasons allowing an evolutionary conserved and benign protein, as PrPC is, to turn into a high affinity receptor for pathologic misfolded oligomers, and to transmit their toxic message into neurons.
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Affiliation(s)
- Caterina Peggion
- Department of Biomedical Sciences, University of Padova, Via Bassi 58/B, 35131 Padova, Italy.
| | - Alessandro Bertoli
- Department of Biomedical Sciences, University of Padova, Via Bassi 58/B, 35131 Padova, Italy
| | - M Catia Sorgato
- Department of Biomedical Sciences, University of Padova, Via Bassi 58/B, 35131 Padova, Italy; C.N.R. Institute of Neuroscience, University of Padova, Via Bassi 58/B, 35131 Padova, Italy.
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142
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Walsh DM, Selkoe DJ. A critical appraisal of the pathogenic protein spread hypothesis of neurodegeneration. Nat Rev Neurosci 2016; 17:251-60. [PMID: 26988744 DOI: 10.1038/nrn.2016.13] [Citation(s) in RCA: 207] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There has been an explosion in the number of papers discussing the hypothesis of 'pathogenic spread' in neurodegenerative disease - the idea that abnormal forms of disease-associated proteins, such as tau or α-synuclein, physically move from neuron to neuron to induce disease progression. However, whether inter-neuronal spread of protein aggregates actually occurs in humans and, if so, whether it causes symptom onset remain uncertain. Even if pathogenic spread is proven in humans, it is unclear how much this would alter the specific therapeutic approaches that are in development. A critical appraisal of this increasingly popular hypothesis thus seems both important and timely.
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Affiliation(s)
- Dominic M Walsh
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Dennis J Selkoe
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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143
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Thackray AM, Bujdoso R. Elevated PrPC Expression Predisposes to Increased HSV-1 Pathogenicity. ACTA ACUST UNITED AC 2016; 17:41-52. [PMID: 16542005 DOI: 10.1177/095632020601700106] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PrPC is a ubiquitously expressed glycophos-phatidylinositol-linked cell-surface glycoprotein found primarily in neural tissue. Although its normal function has not been established, there is evidence suggesting that PrPC is involved in cell signalling and cellular homeostasis. This suggests that variation in neuronal expression levels of this protein contributes towards pathogenicity induced by neurotropic agents. We have investigated the pathological response to infection with herpes simplex virus type-1 (HSV-1) in strains of mice that express different levels of PrPC. Prnp−/− mice fail to express PrPC due to an interruption in the open reading frame of the Prnp gene, whilst tg19 and tga20 mice express approximately 5 and 10 times more PrPC protein, respectively, than wild-type animals. Mice that express normal or increased levels of PrPC protein were more susceptible to acute HSV-1 infection than Prnp−/− mice. Following ear pinna inoculation with HSV-1 SC16, the order of susceptibility was tga20>tg19>wild-type> Prnp−/−. This trend was reversed when latent virus was assessed. Prnp−/− mice expressed significantly higher levels of latency-associated transcript-positive neurons in various tissues when compared with wild-type, tg19 and tga20 mice. Collectively, our data show that acute HSV-1 replication proceeds more efficiently in neuronal tissue that expresses PrPC protein and lends support to the view that this protein is involved in regulation of neurotropic viral pathogenesis. This suggests that interference of PrPC expression, or possible biochemical pathways associated with its function, may serve as an effective means of limiting the pathogenesis of acute HSV-1 infection.
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Affiliation(s)
- Alana M Thackray
- Centre for Veterinary Science, Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 OES, UK
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144
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Tang Z, Ma J, Zhang W, Gong C, He J, Wang Y, Yu G, Yuan C, Wang X, Sun Y, Ma J, Liu F, Zhao Y. The Role of Prion Protein Expression in Predicting Gastric Cancer Prognosis. J Cancer 2016; 7:984-90. [PMID: 27313789 PMCID: PMC4910591 DOI: 10.7150/jca.14237] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/15/2016] [Indexed: 12/26/2022] Open
Abstract
Previous reports indicated that prion protein (PrP) is involved in gastric cancer (GC) development and progression, but its role in GC prognosis has been poorly characterized. A total of 480 GC patients were recruited in this retrospective study. PrP expression in cancerous and non-cancerous gastric tissues was detected by using the tissue microarray and immunohistochemical staining techniques. Our results showed that the PrP expression in GC was significantly less frequent than that in the non-cancerous gastric tissue (44.4% vs 66.4%, P < 0.001). Cox regression analysis revealed that PrP expression was associated with TNM stage, survival status and survival time. GC patients with higher TNM stages (stages II, III and IV) had significantly lower PrP expression levels in tumors than those with lower TNM stages (stages 0 and I). Kaplan-Meier survival curves revealed that negative PrP expression was associated with poor overall survival (log-rank test: P < 0.001). The mean survival time for patients with negative PrP expression was significant lower than those with positive PrP expression (43.0±28.5m vs. 53.9±31.1m, P<0.001). In multivariate Cox hazard regression, PrP expression was an independent prognostic factor for GC survival, with a HR (hazard ratio) of 0.687 (95%CI:0.520-0.907, P=0.008). Our results revealed that negative PrP expression could independently predict worse outcome in GC and thereby could be used to guide the clinical practice.
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Affiliation(s)
- Zhaoqing Tang
- 1. Department of General surgery, Zhongshan Hospital, Fudan University, Shanghai, P.R. China
| | - Ji Ma
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China
| | - Wei Zhang
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China;; 5. Department of Pathology, Shanghai Pulmonary Hospital, Tongji University, Shanghai, P.R. China
| | - Changguo Gong
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China
| | - Jing He
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China
| | - Ying Wang
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China;; 3. Department of Physiology, Renji College, Wenzhou Medical University, Wenzhou, P.R. China
| | - Guohua Yu
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China
| | - Chonggang Yuan
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China
| | - Xuefei Wang
- 1. Department of General surgery, Zhongshan Hospital, Fudan University, Shanghai, P.R. China
| | - Yihong Sun
- 1. Department of General surgery, Zhongshan Hospital, Fudan University, Shanghai, P.R. China
| | - Jiyan Ma
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China;; 4. Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, USA
| | - Fenglin Liu
- 1. Department of General surgery, Zhongshan Hospital, Fudan University, Shanghai, P.R. China
| | - Yulan Zhao
- 2. School of Life Sciences, East China Normal University, Shanghai, P.R. China
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145
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Properzi F, Badhan A, Klier S, Schmidt C, Klöhn PC, Wadsworth JDF, Clarke AR, Jackson GS, Collinge J. Physical, chemical and kinetic factors affecting prion infectivity. Prion 2016; 10:251-61. [PMID: 27282252 PMCID: PMC4981209 DOI: 10.1080/19336896.2016.1181250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The mouse-adapted scrapie prion strain RML is one of the most widely used in prion research. The introduction of a cell culture-based assay of RML prions, the scrapie cell assay (SCA) allows more rapid and precise prion titration. A semi-automated version of this assay (ASCA) was applied to explore a range of conditions that might influence the infectivity and properties of RML prions. These include resistance to freeze-thaw procedures; stability to endogenous proteases in brain homogenate despite prolonged exposure to varying temperatures; distribution of infective material between pellet and supernatant after centrifugation, the effect of reducing agents and the influence of detergent additives on the efficiency of infection. Apparent infectivity is increased significantly by interaction with cationic detergents. Importantly, we have also elucidated the relationship between the duration of exposure of cells to RML prions and the transmission of infection. We established that the infection process following contact of cells with RML prions is rapid and followed an exponential time course, implying a single rate-limiting process.
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Affiliation(s)
- Francesca Properzi
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
| | - Anjna Badhan
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
| | - Steffi Klier
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
| | - Christian Schmidt
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
| | - Peter C Klöhn
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
| | - Jonathan D F Wadsworth
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
| | - Anthony R Clarke
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
| | - Graham S Jackson
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
| | - John Collinge
- a MRC Prion Unit, Department of Neurodegenerative Disease , UCL Institute of Neurology , London , UK
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146
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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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147
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Energy landscapes of a mechanical prion and their implications for the molecular mechanism of long-term memory. Proc Natl Acad Sci U S A 2016; 113:5006-11. [PMID: 27091989 DOI: 10.1073/pnas.1602702113] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aplysia cytoplasmic polyadenylation element binding (CPEB) protein, a translational regulator that recruits mRNAs and facilitates translation, has been shown to be a key component in the formation of long-term memory. Experimental data show that CPEB exists in at least a low-molecular weight coiled-coil oligomeric form and an amyloid fiber form involving the Q-rich domain (CPEB-Q). Using a coarse-grained energy landscape model, we predict the structures of the low-molecular weight oligomeric form and the dynamics of their transitions to the β-form. Up to the decamer, the oligomeric structures are predicted to be coiled coils. Free energy profiles confirm that the coiled coil is the most stable form for dimers and trimers. The structural transition from α to β is shown to be concentration dependent, with the transition barrier decreasing with increased concentration. We observe that a mechanical pulling force can facilitate the α-helix to β-sheet (α-to-β) transition by lowering the free energy barrier between the two forms. Interactome analysis of the CPEB protein suggests that its interactions with the cytoskeleton could provide the necessary mechanical force. We propose that, by exerting mechanical forces on CPEB oligomers, an active cytoskeleton can facilitate fiber formation. This mechanical catalysis makes possible a positive feedback loop that would help localize the formation of CPEB fibers to active synapse areas and mark those synapses for forming a long-term memory after the prion form is established. The functional role of the CPEB helical oligomers in this mechanism carries with it implications for targeting such species in neurodegenerative diseases.
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148
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Sharov AA. Coenzyme world model of the origin of life. Biosystems 2016; 144:8-17. [PMID: 26968100 DOI: 10.1016/j.biosystems.2016.03.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 12/23/2022]
Abstract
The origin of life means the emergence of heritable and evolvable self-reproduction. However the mechanisms of primordial heredity were different from those in contemporary cells. Here I argue that primordial life had no nucleic acids; instead heritable signs were represented by isolated catalytically active self-reproducing molecules, similar to extant coenzymes, which presumably colonized surfaces of oil droplets in water. The model further assumes that coenzyme-like molecules (CLMs) changed surface properties of oil droplets (e.g., by oxidizing terminal carbons), and in this way created and sustained favorable conditions for their own self-reproduction. Such niche-dependent self-reproduction is a necessary condition for cooperation between different kinds of CLMs because they have to coexist in the same oil droplets and either succeed or perish together. Additional kinds of hereditary molecules were acquired via coalescence of oil droplets carrying different kinds of CLMs or via modification of already existing CLMs. Eventually, polymerization of CLMs became controlled by other polymers used as templates; and this kind of template-based synthesis eventually resulted in the emergence of RNA-like replicons. Apparently, oil droplets transformed into the outer membrane of cells via engulfing water, stabilization of the surface, and osmoregulation. In result, the metabolism was internalized allowing cells to accumulate free-floating resources (e.g., animoacids, ATP), which was a necessary condition for the development of protein synthesis. Thus, life originated from simple but already functional molecules, and its gradual evolution towards higher complexity was driven by cooperation and natural selection.
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Affiliation(s)
- Alexei A Sharov
- National Institute on Aging, Genetics Laboratory, 251 Bayview Blvd., Baltimore, MD 21224, USA.
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149
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Wickner RB, Kelly AC. Prions are affected by evolution at two levels. Cell Mol Life Sci 2016; 73:1131-44. [PMID: 26713322 PMCID: PMC4762734 DOI: 10.1007/s00018-015-2109-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 12/30/2022]
Abstract
Prions, infectious proteins, can transmit diseases or be the basis of heritable traits (or both), mostly based on amyloid forms of the prion protein. A single protein sequence can be the basis for many prion strains/variants, with different biological properties based on different amyloid conformations, each rather stably propagating. Prions are unique in that evolution and selection work at both the level of the chromosomal gene encoding the protein, and on the prion itself selecting prion variants. Here, we summarize what is known about the evolution of prion proteins, both the genes and the prions themselves. We contrast the one known functional prion, [Het-s] of Podospora anserina, with the known disease prions, the yeast prions [PSI+] and [URE3] and the transmissible spongiform encephalopathies of mammals.
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Affiliation(s)
- Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bldg. 8, Room 225, 8 Center Drive MSC 0830, Bethesda, MD, 20892-0830, USA.
| | - Amy C Kelly
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bldg. 8, Room 225, 8 Center Drive MSC 0830, Bethesda, MD, 20892-0830, USA.
- NCAUR, Agricultural Research Service, U.S. Department of Agriculture, 1815 N. University St., Peoria, IL, 61604, USA.
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150
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Protective V127 prion variant prevents prion disease by interrupting the formation of dimer and fibril from molecular dynamics simulations. Sci Rep 2016; 6:21804. [PMID: 26906032 PMCID: PMC4764842 DOI: 10.1038/srep21804] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/01/2016] [Indexed: 12/12/2022] Open
Abstract
Recent studies uncovered a novel protective prion protein variant: V127 variant, which was reported intrinsically resistant to prion conversion and propagation. However, the structural basis of its protective effect is still unknown. To uncover the origin of the protective role of V127 variant, molecular dynamics simulations were performed to explore the influence of G127V mutation on two key processes of prion propagation: dimerization and fibril formation. The simulation results indicate V127 variant is unfavorable to form dimer by reducing the main-chain H-bond interactions. The simulations of formed fibrils consisting of β1 strand prove V127 variant will make the formed fibril become unstable and disorder. The weaker interaction energies between layers and reduced H-bonds number for V127 variant reveal this mutation is unfavorable to the formation of stable fibril. Consequently, we find V127 variant is not only unfavorable to the formation of dimer but also unfavorable to the formation of stable core and fibril, which can explain the mechanism on the protective role of V127 variant from the molecular level. Our findings can deepen the understanding of prion disease and may guide the design of peptide mimetics or small molecule to mimic the protective effect of V127 variant.
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