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Calcineurin Activation by Prion Protein Induces Neurotoxicity via Mitochondrial Reactive Oxygen Species. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:5572129. [PMID: 34394828 PMCID: PMC8363446 DOI: 10.1155/2021/5572129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 07/01/2021] [Accepted: 07/14/2021] [Indexed: 01/02/2023]
Abstract
Prion diseases are caused by PrPsc accumulation in the brain, which triggers dysfunctional mitochondrial injury and reactive oxygen species (ROS) generation in neurons. Recent studies on prion diseases suggest that endoplasmic reticulum (ER) stress induced by misfolding proteins such as misfolded prion protein results in activation of calcineurin. Calcineurin is a calcium-related protein phosphatase of type 2B that exists in copious quantities in the brain and acts as a critical nodal component in the control of cellular functions. To investigate the relationship between calcineurin and intracellular ROS, we assessed the alteration of CaN and ROS induced by prion peptide (PrP) 106-126. Human prion peptide increased mitochondrial ROS by activating calcineurin, and the inhibition of calcineurin activity protected mitochondrial function and neuronal apoptosis in neuronal cells. These results suggest that calcineurin plays a pivotal role in neuronal apoptosis by mediating mitochondrial injury and ROS in prion diseases.
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2
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Moon JH, Hong JM, Park SY. The antidiabetic drug troglitazone protects against PrP (106‑126)‑induced neurotoxicity via the PPARγ‑autophagy pathway in neuronal cells. Mol Med Rep 2021; 23:430. [PMID: 33846779 PMCID: PMC8047904 DOI: 10.3892/mmr.2021.12069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 03/16/2021] [Indexed: 12/11/2022] Open
Abstract
Prion diseases, which involve the alteration of cellular prion protein into a misfolded isoform, disrupt the central nervous systems of humans and animals alike. Prior research has suggested that peroxisome proliferator-activator receptor (PPAR)γ and autophagy provide some protection against neurodegeneration. PPARs are critical to lipid metabolism regulation and autophagy is one of the main cellular mechanisms by which cell function and homeostasis is maintained. The present study examined the effect of troglitazone, a PPARγ agonist, on autophagy flux in a prion peptide (PrP) (106–126)-mediated neurodegeneration model. Western blot analysis confirmed that treatment with troglitazone increased LC3-II and p62 protein expression, whereas an excessive increase in autophagosomes was verified by transmission electron microscopy. Troglitazone weakened PrP (106–126)-mediated neurotoxicity via PPARγ activation and autophagy flux inhibition. A PPARγ antagonist blocked PPARγ activation as well as the neuroprotective effects induced by troglitazone treatment, indicating that PPARγ deactivation impaired troglitazone-mediated protective effects. In conclusion, the present study demonstrated that troglitazone protected primary neuronal cells against PrP (106–126)-induced neuronal cell death by inhibiting autophagic flux and activating PPARγ signals. These results suggested that troglitazone may be a useful therapeutic agent for the treatment of neurodegenerative disorders and prion diseases.
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Affiliation(s)
- Ji-Hong Moon
- Biosafety Research Institute, College of Veterinary Medicine, Jeonbuk National University, Iksan, Jeonbuk 54596, Republic of Korea
| | - Jeong-Min Hong
- Biosafety Research Institute, College of Veterinary Medicine, Jeonbuk National University, Iksan, Jeonbuk 54596, Republic of Korea
| | - Sang-Youel Park
- Biosafety Research Institute, College of Veterinary Medicine, Jeonbuk National University, Iksan, Jeonbuk 54596, Republic of Korea
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3
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Marín-Moreno A, Espinosa JC, Torres JM. Transgenic mouse models for the study of prion diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:147-177. [PMID: 32958231 DOI: 10.1016/bs.pmbts.2020.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Prions are unique agents that challenge the molecular biology dogma by transmitting information on the protein level. They cause neurodegenerative diseases that lack of any cure or treatment called transmissible spongiform encephalopathies. The function of the normal form of the prion protein, the exact mechanism of prion propagation between species as well as at the cellular level and neuron degeneration remains elusive. However, great amount of information known for all these aspects has been achieved thanks to the use of animal models and more precisely to transgenic mouse models. In this chapter, the main contributions of these powerful research tools in the prion field are revised.
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Affiliation(s)
- Alba Marín-Moreno
- Centro de Investigación en Sanidad Animal (CISA-INIA), Madrid, Spain
| | | | - Juan María Torres
- Centro de Investigación en Sanidad Animal (CISA-INIA), Madrid, Spain.
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Scialò C, De Cecco E, Manganotti P, Legname G. Prion and Prion-Like Protein Strains: Deciphering the Molecular Basis of Heterogeneity in Neurodegeneration. Viruses 2019; 11:E261. [PMID: 30875755 PMCID: PMC6466326 DOI: 10.3390/v11030261] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/08/2019] [Accepted: 03/10/2019] [Indexed: 12/12/2022] Open
Abstract
Increasing evidence suggests that neurodegenerative disorders share a common pathogenic feature: the presence of deposits of misfolded proteins with altered physicochemical properties in the Central Nervous System. Despite a lack of infectivity, experimental data show that the replication and propagation of neurodegenerative disease-related proteins including amyloid-β (Aβ), tau, α-synuclein and the transactive response DNA-binding protein of 43 kDa (TDP-43) share a similar pathological mechanism with prions. These observations have led to the terminology of "prion-like" to distinguish between conditions with noninfectious characteristics but similarities with the prion replication and propagation process. Prions are considered to adapt their conformation to changes in the context of the environment of replication. This process is known as either prion selection or adaptation, where a distinct conformer present in the initial prion population with higher propensity to propagate in the new environment is able to prevail over the others during the replication process. In the last years, many studies have shown that prion-like proteins share not only the prion replication paradigm but also the specific ability to aggregate in different conformations, i.e., strains, with relevant clinical, diagnostic and therapeutic implications. This review focuses on the molecular basis of the strain phenomenon in prion and prion-like proteins.
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Affiliation(s)
- Carlo Scialò
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy.
| | - Elena De Cecco
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy.
| | - Paolo Manganotti
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, University Hospital and Health Services of Trieste, University of Trieste, 34149 Trieste, Italy.
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy.
- ELETTRA Sincrotrone Trieste S.C.p.A, Basovizza, 34149 Trieste, Italy.
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5
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Mercer RCC, Daude N, Dorosh L, Fu ZL, Mays CE, Gapeshina H, Wohlgemuth SL, Acevedo-Morantes CY, Yang J, Cashman NR, Coulthart MB, Pearson DM, Joseph JT, Wille H, Safar JG, Jansen GH, Stepanova M, Sykes BD, Westaway D. A novel Gerstmann-Sträussler-Scheinker disease mutation defines a precursor for amyloidogenic 8 kDa PrP fragments and reveals N-terminal structural changes shared by other GSS alleles. PLoS Pathog 2018; 14:e1006826. [PMID: 29338055 PMCID: PMC5786331 DOI: 10.1371/journal.ppat.1006826] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 01/26/2018] [Accepted: 12/18/2017] [Indexed: 11/29/2022] Open
Abstract
To explore pathogenesis in a young Gerstmann-Sträussler-Scheinker Disease (GSS) patient, the corresponding mutation, an eight-residue duplication in the hydrophobic region (HR), was inserted into the wild type mouse PrP gene. Transgenic (Tg) mouse lines expressing this mutation (Tg.HRdup) developed spontaneous neurologic syndromes and brain extracts hastened disease in low-expressor Tg.HRdup mice, suggesting de novo formation of prions. While Tg.HRdup mice exhibited spongiform change, PrP aggregates and the anticipated GSS hallmark of a proteinase K (PK)-resistant 8 kDa fragment deriving from the center of PrP, the LGGLGGYV insertion also imparted alterations in PrP's unstructured N-terminus, resulting in a 16 kDa species following thermolysin exposure. This species comprises a plausible precursor to the 8 kDa PK-resistant fragment and its detection in adolescent Tg.HRdup mice suggests that an early start to accumulation could account for early disease of the index case. A 16 kDa thermolysin-resistant signature was also found in GSS patients with P102L, A117V, H187R and F198S alleles and has coordinates similar to GSS stop codon mutations. Our data suggest a novel shared pathway of GSS pathogenesis that is fundamentally distinct from that producing structural alterations in the C-terminus of PrP, as observed in other prion diseases such as Creutzfeldt-Jakob Disease and scrapie. Prion diseases can be sporadic, infectious or genetic. The central event of all prion diseases is the structural conversion of the cellular prion protein (PrPC) to its disease associated conformer, PrPSc. Gerstmann-Sträussler-Scheinker Disease (GSS) is a genetic prion disease presenting as a multi-systemic neurological syndrome. A novel mutation, an eight amino acid insertion, was discovered in a young GSS patient. We created transgenic mice expressing this mutation and found that they recapitulate key features of the disease; namely PrP deposition in the brain and a low molecular weight proteinase K (PK) resistant internal PrP fragment. While structural investigations did not reveal a gross alteration in the conformation of this mutant PrP, the insertion lying at the boundary of the globular domain causes alterations in the unstructured amino terminal portion of the protein such that it becomes resistant to digestion by the enzyme thermolysin. We demonstrate by kinetic analysis and sequential digestion that this novel thermolysin resistant species is a precursor to the pathognomonic PK resistant fragment. Analysis of samples from other GSS patients revealed this same signature, suggesting a common molecular pathway.
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Affiliation(s)
- Robert C. C. Mercer
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Nathalie Daude
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Lyudmyla Dorosh
- National Research Council of Canada, Edmonton, Alberta, Canada
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Ze-Lin Fu
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Charles E. Mays
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Hristina Gapeshina
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Serene L. Wohlgemuth
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | | | - Jing Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Neil R. Cashman
- Brain Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael B. Coulthart
- Canadian Creutzfeldt-Jakob Disease Surveillance System, Centre for Foodborne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Ottawa, Ontario, Canada
| | - Dawn M. Pearson
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Jeffrey T. Joseph
- Hotchkiss Brain Institute and Calgary Laboratory Services, University of Calgary, Calgary, Alberta, Canada
| | - Holger Wille
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jiri G. Safar
- Departments of Pathology and Neurology, School of Medicine Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Gerard H. Jansen
- Canadian Creutzfeldt-Jakob Disease Surveillance System, Centre for Foodborne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Ottawa, Ontario, Canada
- Division of Anatomical Pathology, University of Ottawa, Ottawa, Ontario, Canada
| | - Maria Stepanova
- National Research Council of Canada, Edmonton, Alberta, Canada
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Brian D. Sykes
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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6
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Nonno R, Angelo Di Bari M, Agrimi U, Pirisinu L. Transmissibility of Gerstmann-Sträussler-Scheinker syndrome in rodent models: New insights into the molecular underpinnings of prion infectivity. Prion 2017; 10:421-433. [PMID: 27892798 PMCID: PMC5161296 DOI: 10.1080/19336896.2016.1239686] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Prion diseases, or transmissible spongiform encephalopathies, have revealed the bewildering phenomenon of transmissibility in neurodegenerative diseases. Hence, the experimental transmissibility of prion-like neurodegenerative diseases via template directed misfolding has become the focus of intense research. Gerstmann-Sträussler-Scheinker disease (GSS) is an inherited prion disease associated with mutations in the prion protein gene. However, with the exception of a few GSS cases with P102L mutation characterized by co-accumulation of protease-resistant PrP core (PrPres) of ∼21 kDa, attempts to transmit to rodents GSS associated to atypical misfolded prion protein with ∼8 kDa PrPres have been unsuccessful. As a result, these GSS subtypes have often been considered as non-transmissible proteinopathies rather than true prion diseases. In a recent study we inoculated bank voles with GSS cases associated with P102L, A117V and F198S mutations and found that they transmitted efficiently and produced distinct pathological phenotypes, irrespective of the presence of 21 kDa PrPres in the inoculum. This study demonstrates that GSS is a genuine prion disease characterized by both transmissibility and strain variation. We discuss the implications of these findings for the understanding of the heterogeneous clinic-pathological phenotypes of GSS and of the molecular underpinnings of prion infectivity.
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Affiliation(s)
- Romolo Nonno
- a Department of Veterinary Public Health and Food Safety , Istituto Superiore di Sanità , Rome , Italy
| | - Michele Angelo Di Bari
- a Department of Veterinary Public Health and Food Safety , Istituto Superiore di Sanità , Rome , Italy
| | - Umberto Agrimi
- a Department of Veterinary Public Health and Food Safety , Istituto Superiore di Sanità , Rome , Italy
| | - Laura Pirisinu
- a Department of Veterinary Public Health and Food Safety , Istituto Superiore di Sanità , Rome , Italy
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7
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Watts JC, Prusiner SB. Experimental Models of Inherited PrP Prion Diseases. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a027151. [PMID: 28096244 DOI: 10.1101/cshperspect.a027151] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The inherited prion protein (PrP) prion disorders, which include familial Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker disease, and fatal familial insomnia, constitute ∼10%-15% of all PrP prion disease cases in humans. Attempts to generate animal models of these disorders using transgenic mice expressing mutant PrP have produced variable results. Although many lines of mice develop spontaneous signs of neurological illness with accompanying prion disease-specific neuropathological changes, others do not. Furthermore, demonstrating the presence of protease-resistant PrP species and prion infectivity-two of the hallmarks of the PrP prion disorders-in the brains of spontaneously sick mice has proven particularly challenging. Here, we review the progress that has been made toward developing accurate mouse models of the inherited PrP prion disorders.
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Affiliation(s)
- Joel C Watts
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Biochemistry, University of Toronto, Toronto, Ontario M5T 2S8, Canada
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases, Departments of Neurology and Biochemistry and Biophysics, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143
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8
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PrP P102L and Nearby Lysine Mutations Promote Spontaneous In Vitro Formation of Transmissible Prions. J Virol 2017; 91:JVI.01276-17. [PMID: 28835493 DOI: 10.1128/jvi.01276-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 08/14/2017] [Indexed: 12/16/2022] Open
Abstract
Accumulation of fibrillar protein aggregates is a hallmark of many diseases. While numerous proteins form fibrils by prion-like seeded polymerization in vitro, only some are transmissible and pathogenic in vivo To probe the structural features that confer transmissibility to prion protein (PrP) fibrils, we have analyzed synthetic PrP amyloids with or without the human prion disease-associated P102L mutation. The formation of infectious prions from PrP molecules in vitro has required cofactors and/or unphysiological denaturing conditions. Here, we demonstrate that, under physiologically compatible conditions without cofactors, the P102L mutation in recombinant hamster PrP promoted prion formation when seeded by minute amounts of scrapie prions in vitro Surprisingly, combination of the P102L mutation with charge-neutralizing substitutions of four nearby lysines promoted spontaneous prion formation. When inoculated into hamsters, both of these types of synthetic prions initiated substantial accumulation of prion seeding activity and protease-resistant PrP without transmissible spongiform encephalopathy (TSE) clinical signs or notable glial activation. Our evidence suggests that PrP's centrally located proline and lysine residues act as conformational switches in the in vitro formation of transmissible PrP amyloids.IMPORTANCE Many diseases involve the damaging accumulation of specific misfolded proteins in thread-like aggregates. These threads (fibrils) are capable of growing on the ends by seeding the refolding and incorporation of the normal form of the given protein. In many cases such aggregates can be infectious and propagate like prions when transmitted from one individual host to another. Some transmitted aggregates can cause fatal disease, as with human iatrogenic prion diseases, while other aggregates appear to be relatively innocuous. The factors that distinguish infectious and pathogenic protein aggregates from more innocuous ones are poorly understood. Here we have compared the combined effects of prion seeding and mutations of prion protein (PrP) on the structure and transmission properties of synthetic PrP aggregates. Our results highlight the influence of specific sequence features in the normally unstructured region of PrP that influence the infectious and neuropathogenic properties of PrP-derived aggregates.
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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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10
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Abstract
Prion diseases are characterized by the deposition of amyloids, misfolded conformers of the prion protein. The misfolded conformation is self-replicating, by a mechanism solely enciphered in the conformation of the protein. Because of low solubility and heterogeneous aggregate sizes, the detailed atomic structure of the infectious isoform is still unknown. Progress has, however, been made, and has allowed insights into the structural and disease-related mechanisms of prions. Many structural models have been proposed, and a number of them support a consensus trimeric β-helical model, significantly more complex than simple amyloid models. There is evidence that such complexity may be a necessary property of prion structure. Knowledge of the structure of prions will provide a greater understanding of the protein isoform conversion mechanism, and could eventually lead to rationally designed intervention strategies.
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Affiliation(s)
- Gerald Stubbs
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 53723
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143
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11
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PrP Knockout Cells Expressing Transmembrane PrP Resist Prion Infection. J Virol 2017; 91:JVI.01686-16. [PMID: 27847358 DOI: 10.1128/jvi.01686-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/01/2016] [Indexed: 11/20/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI) anchoring of the prion protein (PrPC) influences PrPC misfolding into the disease-associated isoform, PrPres, as well as prion propagation and infectivity. GPI proteins are found in cholesterol- and sphingolipid-rich membrane regions called rafts. Exchanging the GPI anchor for a nonraft transmembrane sequence redirects PrPC away from rafts. Previous studies showed that nonraft transmembrane PrPC variants resist conversion to PrPres when transfected into scrapie-infected N2a neuroblastoma cells, likely due to segregation of transmembrane PrPC and GPI-anchored PrPres in distinct membrane environments. Thus, it remained unclear whether transmembrane PrPC might convert to PrPres if seeded by an exogenous source of PrPres not associated with host cell rafts and without the potential influence of endogenous expression of GPI-anchored PrPC To further explore these questions, constructs containing either a C-terminal wild-type GPI anchor signal sequence or a nonraft transmembrane sequence containing a flexible linker were expressed in a cell line derived from PrP knockout hippocampal neurons, NpL2. NpL2 cells have physiological similarities to primary neurons, representing a novel and advantageous model for studying transmissible spongiform encephalopathy (TSE) infection. Cells were infected with inocula from multiple prion strains and in different biochemical states (i.e., membrane bound as in brain microsomes from wild-type mice or purified GPI-anchorless amyloid fibrils). Only GPI-anchored PrPC supported persistent PrPres propagation. Our data provide strong evidence that in cell culture GPI anchor-directed membrane association of PrPC is required for persistent PrPres propagation, implicating raft microdomains as a location for conversion. IMPORTANCE Mechanisms of prion propagation, and what makes them transmissible, are poorly understood. Glycosylphosphatidylinositol (GPI) membrane anchoring of the prion protein (PrPC) directs it to specific regions of cell membranes called rafts. In order to test the importance of the raft environment on prion propagation, we developed a novel model for prion infection where cells expressing either GPI-anchored PrPC or transmembrane-anchored PrPC, which partitions it to a different location, were treated with infectious, misfolded forms of the prion protein, PrPres We show that only GPI-anchored PrPC was able to convert to PrPres and able to serially propagate. The results strongly suggest that GPI anchoring and the localization of PrPC to rafts are crucial to the ability of PrPC to propagate as a prion.
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Moreno JA, Telling GC. Insights into Mechanisms of Transmission and Pathogenesis from Transgenic Mouse Models of Prion Diseases. Methods Mol Biol 2017; 1658:219-252. [PMID: 28861793 DOI: 10.1007/978-1-4939-7244-9_16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Prions represent a new paradigm of protein-mediated information transfer. In the case of mammals, prions are the cause of fatal, transmissible neurodegenerative diseases, sometimes referred to as transmissible spongiform encephalopathies (TSEs), which frequently occur as epidemics. An increasing body of evidence indicates that the canonical mechanism of conformational corruption of cellular prion protein (PrPC) by the pathogenic isoform (PrPSc) that is the basis of prion formation in TSEs is common to a spectrum of proteins associated with various additional human neurodegenerative disorders, including the more common Alzheimer's and Parkinson's diseases. The peerless infectious properties of TSE prions, and the unparalleled tools for their study, therefore enable elucidation of mechanisms of template-mediated conformational propagation that are generally applicable to these related disease states. Many unresolved issues remain including the exact molecular nature of the prion, the detailed cellular and molecular mechanisms of prion propagation, and the means by which prion diseases can be both genetic and infectious. In addition, we know little about the mechanism by which neurons degenerate during prion diseases. Tied to this, the physiological role of the normal form of the prion protein remains unclear and it is uncertain whether or not loss of this function contributes to prion pathogenesis. The factors governing the transmission of prions between species remain unclear, in particular the means by which prion strains and PrP primary structure interact to affect interspecies prion transmission. Despite all these unknowns, advances in our understanding of prions have occurred because of their transmissibility to experimental animals, and the development of transgenic (Tg) mouse models has done much to further our understanding about various aspects of prion biology. In this review, we will focus on advances in our understanding of prion biology that occurred in the past 8 years since our last review of this topic.
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Affiliation(s)
- Julie A Moreno
- Cell and Molecular Biology Graduate Program, Molecular, Cellular and Integrative Neuroscience Graduate Program, Department of Microbiology, Immunology and Pathology, Prion Research Center, Colorado State University, Fort Collins, CO, 80523, USA
| | - Glenn C Telling
- Cell and Molecular Biology Graduate Program, Molecular, Cellular and Integrative Neuroscience Graduate Program, Department of Microbiology, Immunology and Pathology, Prion Research Center, Colorado State University, Fort Collins, CO, 80523, USA.
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13
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Miyazawa K, Okada H, Masujin K, Iwamaru Y, Yokoyama T. Infectivity-associated PrP(Sc) and disease duration-associated PrP(Sc) of mouse BSE prions. Prion 2016; 9:394-403. [PMID: 26555211 PMCID: PMC4964868 DOI: 10.1080/19336896.2015.1111507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Disease-related prion protein (PrPSc), which is a structural isoform of the host-encoded cellular prion protein, is thought to be a causative agent of transmissible spongiform encephalopathies. However, the specific role of PrPSc in prion pathogenesis and its relationship to infectivity remain controversial. A time-course study of prion-affected mice was conducted, which showed that the prion infectivity was not simply proportional to the amount of PrPSc in the brain. Centrifugation (20,000 ×g) of the brain homogenate showed that most of the PrPSc was precipitated into the pellet, and the supernatant contained only a slight amount of PrPSc. Interestingly, mice inoculated with the obtained supernatant showed incubation periods that were approximately 15 d longer than those of mice inoculated with the crude homogenate even though both inocula contained almost the same infectivity. Our results suggest that a small population of fine PrPSc may be responsible for prion infectivity and that large, aggregated PrPSc may contribute to determining prion disease duration.
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Affiliation(s)
- Kohtaro Miyazawa
- a Influenza and Prion Disease Research Center; National Institute of Animal Health ; Tsukuba , Ibaraki , Japan
| | - Hiroyuki Okada
- a Influenza and Prion Disease Research Center; National Institute of Animal Health ; Tsukuba , Ibaraki , Japan
| | - Kentaro Masujin
- a Influenza and Prion Disease Research Center; National Institute of Animal Health ; Tsukuba , Ibaraki , Japan
| | - Yoshifumi Iwamaru
- a Influenza and Prion Disease Research Center; National Institute of Animal Health ; Tsukuba , Ibaraki , Japan
| | - Takashi Yokoyama
- a Influenza and Prion Disease Research Center; National Institute of Animal Health ; Tsukuba , Ibaraki , Japan
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14
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Wan W, Wille H, Stöhr J, Kendall A, Bian W, McDonald M, Tiggelaar S, Watts JC, Prusiner SB, Stubbs G. Structural studies of truncated forms of the prion protein PrP. Biophys J 2016; 108:1548-1554. [PMID: 25809267 DOI: 10.1016/j.bpj.2015.01.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/07/2015] [Accepted: 01/13/2015] [Indexed: 11/19/2022] Open
Abstract
Prions are proteins that adopt self-propagating aberrant folds. The self-propagating properties of prions are a direct consequence of their distinct structures, making the understanding of these structures and their biophysical interactions fundamental to understanding prions and their related diseases. The insolubility and inherent disorder of prions have made their structures difficult to study, particularly in the case of the infectious form of the mammalian prion protein PrP. Many investigators have therefore preferred to work with peptide fragments of PrP, suggesting that these peptides might serve as structural and functional models for biologically active prions. We have used x-ray fiber diffraction to compare a series of different-sized fragments of PrP, to determine the structural commonalities among the fragments and the biologically active, self-propagating prions. Although all of the peptides studied adopted amyloid conformations, only the larger fragments demonstrated a degree of structural complexity approaching that of PrP. Even these larger fragments did not adopt the prion structure itself with detailed fidelity, and in some cases their structures were radically different from that of pathogenic PrP(Sc).
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Affiliation(s)
- William Wan
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Holger Wille
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Amy Kendall
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Wen Bian
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Michele McDonald
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Sarah Tiggelaar
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Joel C Watts
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Gerald Stubbs
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee.
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15
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Variably Protease-sensitive Prionopathy in an Apparent Cognitively Normal 93-Year-Old. Alzheimer Dis Assoc Disord 2016; 29:173-6. [PMID: 24845762 DOI: 10.1097/wad.0000000000000049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Wan W, Stöhr J, Kendall A, Stubbs G. Truncated forms of the prion protein PrP demonstrate the need for complexity in prion structure. Prion 2015; 9:333-8. [PMID: 26325658 DOI: 10.1080/19336896.2015.1084464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Self-propagation of aberrant protein folds is the defining characteristic of prions. Knowing the structural basis of self-propagation is essential to understanding prions and their related diseases. Prion rods are amyloid fibrils, but not all amyloids are prions. Prions have been remarkably intractable to structural studies, so many investigators have preferred to work with peptide fragments, particularly in the case of the mammalian prion protein PrP. We compared the structures of a number of fragments of PrP by X-ray fiber diffraction, and found that although all of the peptides adopted amyloid conformations, only the larger fragments adopted conformations that modeled the complexity of self-propagating prions, and even these fragments did not always adopt the PrP structure. It appears that the relatively complex structure of the prion form of PrP is not accessible to short model peptides, and that self-propagation may be tied to a level of structural complexity unobtainable in simple model systems. The larger fragments of PrP, however, are useful to illustrate the phenomenon of deformed templating (heterogeneous seeding), which has important biological consequences.
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Affiliation(s)
- William Wan
- a Department of Biological Sciences and Center for Structural Biology ; Vanderbilt University ; Nashville , TN USA
| | - Jan Stöhr
- b Institute for Neurodegenerative Diseases and Department of Neurology ; University of California, San Francisco ; San Francisco , CA USA
| | - Amy Kendall
- a Department of Biological Sciences and Center for Structural Biology ; Vanderbilt University ; Nashville , TN USA
| | - Gerald Stubbs
- a Department of Biological Sciences and Center for Structural Biology ; Vanderbilt University ; Nashville , TN USA
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17
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Aguilar-Calvo P, García C, Espinosa JC, Andreoletti O, Torres JM. Prion and prion-like diseases in animals. Virus Res 2014; 207:82-93. [PMID: 25444937 DOI: 10.1016/j.virusres.2014.11.026] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/06/2014] [Accepted: 11/24/2014] [Indexed: 11/19/2022]
Abstract
Transmissible spongiform encephalopaties (TSEs) are fatal neurodegenerative diseases characterized by the aggregation and accumulation of the misfolded prion protein in the brain. Other proteins such as β-amyloid, tau or Serum Amyloid-A (SAA) seem to share with prions some aspects of their pathogenic mechanism; causing a variety of so called prion-like diseases in humans and/or animals such as Alzheimer's, Parkinson's, Huntington's, Type II diabetes mellitus or amyloidosis. The question remains whether these misfolding proteins have the ability to self-propagate and transmit in a similar manner to prions. In this review, we describe the prion and prion-like diseases affecting animals as well as the recent findings suggesting the prion-like transmissibility of certain non-prion proteins.
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Affiliation(s)
| | - Consolación García
- Centro de Investigación en Sanidad Animal (CISA-INIA), 28130 Valdeolmos, Madrid, Spain
| | - Juan Carlos Espinosa
- Centro de Investigación en Sanidad Animal (CISA-INIA), 28130 Valdeolmos, Madrid, Spain
| | - Olivier Andreoletti
- INRA, UMR 1225, Interactions Hôtes Agents Pathogènes, École Nationale Vétérinaire de Toulouse, 23 chemin des Capelles, 31076 Toulouse Cedex, France
| | - Juan María Torres
- Centro de Investigación en Sanidad Animal (CISA-INIA), 28130 Valdeolmos, Madrid, Spain.
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18
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Jeffrey M, McGovern G, Makarava N, González L, Kim YS, Rohwer RG, Baskakov IV. Pathology of SSLOW, a transmissible and fatal synthetic prion protein disorder, and comparison with naturally occurring classical transmissible spongiform encephalopathies. Neuropathol Appl Neurobiol 2014; 40:296-310. [PMID: 23578208 DOI: 10.1111/nan.12053] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 03/24/2013] [Indexed: 12/16/2022]
Abstract
AIMS Naturally occurring transmissible spongiform encephalopathies (TSEs) accumulate disease-specific forms of prion protein on cell membranes in association with pathognomonic lesions. We wished to determine whether synthetic prion protein disorders recapitulated these and other subcellular TSE-specific changes. METHODS SSLOW is a TSE initiated with refolded synthetic prion protein. Five terminally sick hamsters previously intracerebrally inoculated with third passage SSLOW were examined using light and immunogold electron microscopy. RESULTS SSLOW-affected hamsters showed widespread abnormal prion protein (PrP(SSLOW) ) and amyloid plaques. PrP(SSLOW) accumulated on plasma lemmas of neurites and glia without pathological changes. PrP(SSLOW) also colocalized with increased coated vesicles and pits, coated spiral membrane invaginations and membrane microfolding. PrP(SSLOW) was additionally observed in lysosomes of microglial cells but not of neurones or astrocytes. CONCLUSIONS PrP(SSLOW) is propagated by cell membrane conversion of normal PrP and lethal disease may be linked to the progressive growth of amyloid plaques. Cell membrane changes present in SSLOW are indistinguishable from those of naturally occurring TSEs. However, some lesions found in SSLOW are absent in natural animal TSEs and vice versa. SSLOW may not entirely recapitulate neuropathological features previously described for natural disease. End-stage neuropathology in SSLOW, particularly the nature and distribution of amyloid plaques may be significantly influenced by the early redistribution of seeds within the inoculum and its recirculation following interstitial, perivascular and other drainage pathways. The way in which seeds are distributed and aggregate into plaques in SSLOW has significant overlap with murine APP overexpressing mice challenged with Aβ.
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Affiliation(s)
- M Jeffrey
- Animal Health and Veterinary Laboratories Agency, Lasswade Laboratory, Bush Loan, Penicuik, Midlothian, UK
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19
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Prion neuropathology follows the accumulation of alternate prion protein isoforms after infective titre has peaked. Nat Commun 2014; 5:4347. [PMID: 25005024 PMCID: PMC4104459 DOI: 10.1038/ncomms5347] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/09/2014] [Indexed: 01/02/2023] Open
Abstract
Prions are lethal infectious agents thought to consist of multi-chain forms (PrPSc) of misfolded cellular prion protein (PrPC). Prion propagation proceeds in two distinct mechanistic phases: an exponential phase 1, which rapidly reaches a fixed level of infectivity irrespective of PrPC expression level, and a plateau (phase 2), which continues until clinical onset with duration inversely proportional to PrPC expression level. We hypothesized that neurotoxicity relates to distinct neurotoxic species produced following a pathway switch when prion levels saturate. Here we show a linear increase of proteinase K-sensitive PrP isoforms distinct from classical PrPSc at a rate proportional to PrPC concentration, commencing at the phase transition and rising until clinical onset. The unaltered level of total PrP during phase 1, when prion infectivity increases a million-fold, indicates that prions comprise a small minority of total PrP. This is consistent with PrPC concentration not being rate limiting to exponential prion propagation and neurotoxicity relating to critical concentrations of alternate PrP isoforms whose production is PrPC concentration dependent. Prions (PrP) are infectious agents that cause lethal neurodegenerative diseases. Here the authors study the kinetics of prion propagation in mice and show that the onset of neuropathology occurs during the late phase of disease and is hypothesized to be due to increases in a toxic isoform of PrP that is different from the infectious species.
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20
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Watts JC, Prusiner SB. Mouse models for studying the formation and propagation of prions. J Biol Chem 2014; 289:19841-9. [PMID: 24860095 DOI: 10.1074/jbc.r114.550707] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Prions are self-propagating protein conformers that cause a variety of neurodegenerative disorders in humans and animals. Mouse models have played key roles in deciphering the biology of prions and in assessing candidate therapeutics. The development of transgenic mice that form prions spontaneously in the brain has advanced our understanding of sporadic and genetic prion diseases. Furthermore, the realization that many proteins can become prions has necessitated the development of mouse models for assessing the potential transmissibility of common neurodegenerative diseases. As the universe of prion diseases continues to expand, mouse models will remain crucial for interrogating these devastating illnesses.
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Affiliation(s)
- Joel C Watts
- From the Institute for Neurodegenerative Diseases and the Department of Neurology, University of California, San Francisco, California 94143
| | - Stanley B Prusiner
- From the Institute for Neurodegenerative Diseases and the Department of Neurology, University of California, San Francisco, California 94143
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21
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Abstract
Prions are proteins that acquire alternative conformations that become self-propagating. Transformation of proteins into prions is generally accompanied by an increase in β-sheet structure and a propensity to aggregate into oligomers. Some prions are beneficial and perform cellular functions, whereas others cause neurodegeneration. In mammals, more than a dozen proteins that become prions have been identified, and a similar number has been found in fungi. In both mammals and fungi, variations in the prion conformation encipher the biological properties of distinct prion strains. Increasing evidence argues that prions cause many neurodegenerative diseases (NDs), including Alzheimer's, Parkinson's, Creutzfeldt-Jakob, and Lou Gehrig's diseases, as well as the tauopathies. The majority of NDs are sporadic, and 10% to 20% are inherited. The late onset of heritable NDs, like their sporadic counterparts, may reflect the stochastic nature of prion formation; the pathogenesis of such illnesses seems to require prion accumulation to exceed some critical threshold before neurological dysfunction manifests.
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Affiliation(s)
- Stanley B Prusiner
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, California 94143;
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22
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Cervenakova L, Brown P. Advances in screening test development for transmissible spongiform encephalopathies. Expert Rev Anti Infect Ther 2014; 2:873-80. [PMID: 15566331 DOI: 10.1586/14789072.2.6.873] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The blood of patients with transmissible spongiform encephalopathy or prion disease can no longer be considered free of infectivity. There have been two recent reports of highly probable transfusion-associated iatrogenic variant Creutzfeldt-Jakob disease infections, and there is supporting experimental evidence of scrapie transmission by the transfusion of blood from sheep with naturally occurring disease. In the absence of a preclinical diagnostic test for transmissible spongiform encephalopathy, the main precautionary measures undertaken by blood agencies employ donor exclusion criteria, ensuring that the number of any further iatrogenic cases will be small. The development of a sensitive, specific and reliable diagnostic test is urgently needed for early identification of infected individuals in order to ensure the safety of blood supplies. During the past 5 years, significant progress has been made in improving the sensitivity and specificity of tests using brain and lymphoreticular tissues to identify Creutzfeldt-Jakob disease-infected individuals. However, the quest for a blood test is still in its infancy and requires extensive further research.
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Affiliation(s)
- Larisa Cervenakova
- American Red Cross Research and Development, 15601 Crabbs Branch Way, Rockville, MD 20855, USA.
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23
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Lin Z, Zhao D, Yang L. Interaction between misfolded PrP and the ubiquitin-proteasome system in prion-mediated neurodegeneration. Acta Biochim Biophys Sin (Shanghai) 2013; 45:477-84. [PMID: 23449072 DOI: 10.1093/abbs/gmt020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Prion diseases are associated with the conformational conversion of cellular prion protein (PrP(C)) to pathological β-sheet isoforms (PrP(Sc)), which is the infectious agent beyond comprehension. Increasing evidence indicated that an unknown toxic gain of function of PrP(sc) underlies neuronal death. Conversely, strong evidence indicated that cellular prion protein might be directly cytotoxic by mediating neurotoxic signaling of β-sheet-rich conformers independent of prion replication. Furthermore, the common properties of β-sheet-rich isoform such as PrP(Sc) and β amyloid protein become the lynchpin that interprets the general pathological mechanism of protein misfolding diseases. Dysfunction of the ubiquitin-proteasome system (UPS) has been implicated in various protein misfolding diseases. However, the mechanisms of this impairment remain unknown in many cases. In prion disease, prion-infected mouse brains have increased levels of ubiquitin conjugates, which correlate with decreased proteasome function. Both PrP(C) and PrP(Sc) accumulate in cells after proteasome inhibition, which leads to increased cell death. A direct interaction between 20S core particle and PrP isoforms was demonstrated. Here we review the ability of misfolded PrP and UPS to affect each other, which might contribute to the pathological features of prion-mediated neurodegeneration.
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Affiliation(s)
- Zhu Lin
- State Key Laboratories for Agrobiotechnology, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
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24
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Reiniger L, Mirabile I, Lukic A, Wadsworth JDF, Linehan JM, Groves M, Lowe J, Druyeh R, Rudge P, Collinge J, Mead S, Brandner S. Filamentous white matter prion protein deposition is a distinctive feature of multiple inherited prion diseases. Acta Neuropathol Commun 2013; 1:8. [PMID: 24252267 PMCID: PMC4046834 DOI: 10.1186/2051-5960-1-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 03/12/2013] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Sporadic, inherited and acquired prion diseases show distinct histological patterns of abnormal prion protein (PrP) deposits. Many of the inherited prion diseases show striking histological patterns, which often associate with specific mutations. Most reports have focused on the pattern of PrP deposition in the cortical or cerebellar grey matter. RESULTS We observed that the subcortical white matter in inherited prion diseases frequently contained filamentous depositions of abnormal PrP, and we have analysed by immunohistochemistry, immunofluorescence and electron microscopy 35 cases of inherited prion disease seen at the UK National Prion Clinic. We report here that filamentous PrP is abundantly deposited in myelinated fibres in inherited prion diseases, in particular in those with N-terminal mutations. CONCLUSIONS It is possible that the presence of filamentous PrP is related to the pathogenesis of inherited forms, which is different from those sporadic and acquired forms.
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Affiliation(s)
- Lilla Reiniger
- />Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
| | - Ilaria Mirabile
- />Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
| | - Ana Lukic
- />Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London UK
- />National Prion Clinic, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
| | | | | | - Michael Groves
- />Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
| | - Jessica Lowe
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - Ronald Druyeh
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - Peter Rudge
- />National Prion Clinic, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - John Collinge
- />Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London UK
- />National Prion Clinic, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - Simon Mead
- />National Prion Clinic, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
- />MRC Prion Unit, UCL Institute of Neurology, London, UK
| | - Sebastian Brandner
- />Division of Neuropathology, National Hospital for Neurology and Neurosurgery, Queen Square, London UK
- />Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London UK
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25
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Aidt FH, Hasholt LF, Christiansen M, Laursen H. Localization of A11-reactive oligomeric species in prion diseases. Histopathology 2013; 62:994-1001. [PMID: 23570304 DOI: 10.1111/his.12097] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 01/13/2013] [Indexed: 12/16/2022]
Abstract
AIMS To investigate in prion diseases the in-situ localization of prion protein oligomers sharing a common epitope with amyloid oligomers involved in a range of neurodegenerative diseases. METHODS AND RESULTS We performed immunohistochemistry on sporadic Creutzfeldt-Jakob disease (sCJD) (n = 9) and hereditary Gerstmann-Sträussler-Scheinker disease (GSS) (n = 1) specimens with the anti-oligomer antibody A11 to determine the localization of reactive species. We found that A11 reactivity in the sCJD specimens was localized to the cerebral and cerebellar cortices both in spongiform and adjacent, non-spongiform areas, reminiscent of multicentric or diffuse plaques. In the GSS specimens, we found that staining was closely associated with kuru-like plaques, and that A11-reactive species colocalized with protease-resistant prion protein (Prp(Sc)). We also observed sporadic neuronal cytosolic staining in both types of specimen. CONCLUSIONS We confirm that intracellular and extracellular A11-reactive species are present in situ in sCJD cases and GSS, and that immunoreactivity for A11 and Prp(Sc) overlaps. We argue that the A11-reactive species are indeed composed of oligomeric Prp(Sc), and suggest that the toxic effects of Prp(Sc) oligomers could be related to the generic oligomeric conformation recognized by A11.
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Affiliation(s)
- Frederik H Aidt
- Section of Molecular Medicine, Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Copenhagen, Denmark.
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26
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Jeffrey M. Review: Membrane-associated misfolded protein propagation in natural transmissible spongiform encephalopathies (TSEs), synthetic prion diseases and Alzheimer's disease. Neuropathol Appl Neurobiol 2013; 39:196-216. [DOI: 10.1111/nan.12004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 11/06/2012] [Indexed: 12/17/2022]
Affiliation(s)
- M. Jeffrey
- Lasswade Laboratory; Animal Health and Veterinary Laboratories Agency; Penicuik; UK
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27
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Masujin K, Kaku-Ushiki Y, Miwa R, Okada H, Shimizu Y, Kasai K, Matsuura Y, Yokoyama T. The N-terminal sequence of prion protein consists an epitope specific to the abnormal isoform of prion protein (PrP(Sc)). PLoS One 2013; 8:e58013. [PMID: 23469131 PMCID: PMC3585212 DOI: 10.1371/journal.pone.0058013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 01/29/2013] [Indexed: 11/18/2022] Open
Abstract
The conformation of abnormal prion protein (PrPSc) differs from that of cellular prion protein (PrPC), but the precise characteristics of PrPSc remain to be elucidated. To clarify the properties of native PrPSc, we attempted to generate novel PrPSc-specific monoclonal antibodies (mAbs) by immunizing PrP-deficient mice with intact PrPSc purified from bovine spongiform encephalopathy (BSE)-affected mice. The generated mAbs 6A12 and 8D5 selectivity precipitated PrPSc from the brains of prion-affected mice, sheep, and cattle, but did not precipitate PrPC from the brains of healthy animals. In histopathological analysis, mAbs 6A12 and 8D5 strongly reacted with prion-affected mouse brains but not with unaffected mouse brains without antigen retrieval. Epitope analysis revealed that mAbs 8D5 and 6A12 recognized the PrP subregions between amino acids 31–39 and 41–47, respectively. This indicates that a PrPSc-specific epitope exists in the N-terminal region of PrPSc, and mAbs 6A12 and 8D5 are powerful tools with which to detect native and intact PrPSc. We found that the ratio of proteinase K (PK)-sensitive PrPSc to PK-resistant PrPSc was constant throughout the disease time course.
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Affiliation(s)
- Kentaro Masujin
- Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki, Japan
| | | | - Ritsuko Miwa
- Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki, Japan
| | - Hiroyuki Okada
- Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki, Japan
| | - Yoshihisa Shimizu
- Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki, Japan
| | - Kazuo Kasai
- Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki, Japan
| | - Yuichi Matsuura
- Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki, Japan
| | - Takashi Yokoyama
- Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki, Japan
- * E-mail:
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28
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Jackson GS, Mead S, Collinge J. Developing early diagnostics for prion diseases. Neurodegener Dis Manag 2013. [DOI: 10.2217/nmt.12.76] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY The diagnosis of prion disease is typically made late in the clinical course, by which time patients are in an advanced state of neurological decline. This is despite the presence of pathology in many tissues, particularly those of the lymphoreticular and central nervous systems. The recent description of an effective blood assay for variant Creutzfeldt-Jakob disease clearly demonstrates the potential for routine pre-mortem diagnosis, although further progress is required for the detection of sporadic forms of the disease.
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Affiliation(s)
- Graham S Jackson
- MRC Prion Unit, Department of Neurodegenerative Disease, University College London Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Simon Mead
- MRC Prion Unit, Department of Neurodegenerative Disease, University College London Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- National Prion Clinic, National Hospital for Neurology & Neurosurgery, Queen Square, London, WC1N 3BG, UK
| | - John Collinge
- MRC Prion Unit, Department of Neurodegenerative Disease, University College London Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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29
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Solforosi L, Milani M, Mancini N, Clementi M, Burioni R. A closer look at prion strains: characterization and important implications. Prion 2013; 7:99-108. [PMID: 23357828 PMCID: PMC3609129 DOI: 10.4161/pri.23490] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Prions are infectious proteins that are responsible for transmissible spongiform encephalopathies (TSEs) and consist primarily of scrapie prion protein (PrPSc), a pathogenic isoform of the host-encoded cellular prion protein (PrPC). The absence of nucleic acids as essential components of the infectious prions is the most striking feature associated to these diseases. Additionally, different prion strains have been isolated from animal diseases despite the lack of DNA or RNA molecules. Mounting evidence suggests that prion-strain-specific features segregate with different PrPSc conformational and aggregation states.
Strains are of practical relevance in prion diseases as they can drastically differ in many aspects, such as incubation period, PrPSc biochemical profile (e.g., electrophoretic mobility and glycoform ratio) and distribution of brain lesions. Importantly, such different features are maintained after inoculation of a prion strain into genetically identical hosts and are relatively stable across serial passages.
This review focuses on the characterization of prion strains and on the wide range of important implications that the study of prion strains involves.
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Affiliation(s)
- Laura Solforosi
- Laboratory of Microbiology and Virology; University Vita-Salute San Raffaele; Milan, Italy.
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30
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Abdallah A, Wang P, Richt JA, Sreevatsan S. Y145Stop is sufficient to induce de novo generation prions using protein misfolding cyclic amplification. Prion 2012; 6:81-8. [PMID: 22453182 DOI: 10.4161/pri.6.1.18493] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A point mutation in Prnp that converts tyrosine (Y) at position 145 into a stop codon leading to a truncated prion molecule as found in an inherited transmissible spongiform encephalopathy (TSE), Gertsmann-Sträussler-Scheincker syndrome, suggests that the N-terminus of the molecule (spanning amino acids 23-144) likely plays a critical role in prion misfolding as well as in protein-protein interactions. We hypothesized that Y145Stop molecule represents an unstable part of the prion protein that is prone to spontaneous misfolding. Utilizing protein misfolding cyclic amplification (PMCA) we show that the recombinant polypeptide corresponding to the Y145Stop of sheep and deer PRNP can be in vitro converted to PK-resistant PrP (Sc) in presence or absence of preexisting prions. In contrast, recombinant protein full-length PrP (C) did not show a propensity for spontaneous conformational conversion to protease resistant isoforms. Further, we show that seeded or spontaneously misfolded Y145Stop molecules can efficiently convert purified mammalian PrP (C) into protease resistant isoforms. These results establish that the N-terminus of PrP (C) molecule corresponding to residues 23-144 plays a role in seeding and misfolding of mammalian prions.
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Affiliation(s)
- Ahmed Abdallah
- Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN, USA
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Shibano S, Sasaki K, Kidoaki S, Iwaki T. Detection of prion protein oligomers by single molecule fluorescence imaging. Neuropathology 2012; 33:1-6. [PMID: 22537088 DOI: 10.1111/j.1440-1789.2012.01316.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The degree of polymerization of PrP has a close relationship with the pathological mechanisms of prion diseases. We examined, at the molecular level, the polymerization state of PrP in lysates of prion-infected cells using total internal reflection fluorescence microscopy (TIRFM). The crude lysates were fractionated by gel-filtration spin columns according to their molecular size. Both the oligomer-rich and the monomer-rich fractions were probed with fluorescein-labeled anti-PrP antibodies (mAb SAF70 and mAb 8G8). Fluorescent spots of varying intensity were detected, with the ratio of intense fluorescent spots being greater in the oligomer fraction samples with mAb SAF70 than those with 8G8, the specific epitope of which is thought to be buried in abnormal PrP molecules. The results indicated that PrP oligomers could be specifically detected and conformational changes of abnormal PrP molecules observed. Imaging by TIRFM may aid in determining the polymerization state and properties of PrP oligomers in pathological processes.
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Affiliation(s)
- Satoko Shibano
- Department of Neuropathology, Graduate School of Medical Sciences Division of Biomolecular Chemistry, Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka, Japan
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32
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Abstract
The yeast, fungal and mammalian prions determine heritable and infectious traits that are encoded in alternative conformations of proteins. They cause lethal sporadic, familial and infectious neurodegenerative conditions in man, including Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), kuru, sporadic fatal insomnia (SFI) and likely variable protease-sensitive prionopathy (VPSPr). The most prevalent of human prion diseases is sporadic (s)CJD. Recent advances in amplification and detection of prions led to considerable optimism that early and possibly preclinical diagnosis and therapy might become a reality. Although several drugs have already been tested in small numbers of sCJD patients, there is no clear evidence of any agent’s efficacy. Therefore, it remains crucial to determine the full spectrum of sCJD prion strains and the conformational features in the pathogenic human prion protein governing replication of sCJD prions. Research in this direction is essential for the rational development of diagnostic as well as therapeutic strategies. Moreover, there is growing recognition that fundamental processes involved in human prion propagation – intercellular induction of protein misfolding and seeded aggregation of misfolded host proteins – are of far wider significance. This insight leads to new avenues of research in the ever-widening spectrum of age-related human neurodegenerative diseases that are caused by protein misfolding and that pose a major challenge for healthcare.
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Affiliation(s)
- Jiri G Safar
- Department of Pathology, National Prion Disease Surveillance Center, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
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Sajnani G, Silva CJ, Ramos A, Pastrana MA, Onisko BC, Erickson ML, Antaki EM, Dynin I, Vázquez-Fernández E, Sigurdson CJ, Carter JM, Requena JR. PK-sensitive PrP is infectious and shares basic structural features with PK-resistant PrP. PLoS Pathog 2012; 8:e1002547. [PMID: 22396643 PMCID: PMC3291653 DOI: 10.1371/journal.ppat.1002547] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 01/10/2012] [Indexed: 11/25/2022] Open
Abstract
One of the main characteristics of the transmissible isoform of the prion protein (PrPSc) is its partial resistance to proteinase K (PK) digestion. Diagnosis of prion disease typically relies upon immunodetection of PK-digested PrPSc following Western blot or ELISA. More recently, researchers determined that there is a sizeable fraction of PrPSc that is sensitive to PK hydrolysis (sPrPSc). Our group has previously reported a method to isolate this fraction by centrifugation and showed that it has protein misfolding cyclic amplification (PMCA) converting activity. We compared the infectivity of the sPrPSc versus the PK-resistant (rPrPSc) fractions of PrPSc and analyzed the biochemical characteristics of these fractions under conditions of limited proteolysis. Our results show that sPrPSc and rPrPSc fractions have comparable degrees of infectivity and that although they contain different sized multimers, these multimers share similar structural properties. Furthermore, the PK-sensitive fractions of two hamster strains, 263K and Drowsy (Dy), showed strain-dependent differences in the ratios of the sPrPSc to the rPrPSc forms of PrPSc. Although the sPrPSc and rPrPSc fractions have different resistance to PK-digestion, and have previously been shown to sediment differently, and have a different distribution of multimers, they share a common structure and phenotype. Prion diseases are protein misfolding disorders. Different strains of prions are known to have variable resistance to proteinase K (PK) digestion. Furthermore, the same strain possesses both a PK sensitive (sPrPSc) and PK resistant (rPrPSc) aggregate of PrP. We developed methods to isolate the sPrPSc from rPrPSc fraction of the 263K strain of hamster-adapted scrapie. Both fractions were infectious, but have different physico-chemical properties. When we analyzed the lesion targets in the brain produced by each fraction they were essentially identical, suggesting that they were the same strain. The biochemical differences in the phenotypes of these two fractions are due to different sized multimers that share common structural properties. Furthermore, the comparison of the sensitive fractions of two hamster strains, 263K and Drowsy (Dy), showed strain-dependent differences in the ratios of the PK-sensitive to the PK-resistant forms of PrPSc.
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Affiliation(s)
- Gustavo Sajnani
- Department of Medicine, School of Medicine, University of Santiago de Compostela, Santiago de Compostela, Galiza, Spain.
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The extended cell panel assay characterizes the relationship of prion strains RML, 79A, and 139A and reveals conversion of 139A to 79A-like prions in cell culture. J Virol 2012; 86:5297-303. [PMID: 22379091 DOI: 10.1128/jvi.00181-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three commonly used isolates of murine prions, 79A, 139A, and RML, were derived from the so-called Chandler isolate, which was obtained by propagating prions from scrapie-infected goat brain in mice. RML is widely believed to be identical with 139A; however, using the extended cell panel assay (ECPA), we here show that 139A and RML isolates are distinct, while 79A and RML could not be distinguished. We undertook to clone 79A and 139A prions by endpoint dilution in murine neuroblastoma-derived PK1 cells. Cloned 79A prions, when returned to mouse brain, were unchanged and indistinguishable from RML by ECPA. However, 139A-derived clones, when returned to brain, yielded prions distinct from 139A and similar to 79A and RML. Thus, when 139A prions were transferred to PK1 cells, 79A/RML-like prions, either present as a minor component in the brain 139A population or generated by mutation in the cells, were selected and, after being returned to brain, were the major if not only component of the population.
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Monaco S, Fiorini M, Farinazzo A, Ferrari S, Gelati M, Piccardo P, Zanusso G, Ghetti B. Allelic origin of protease-sensitive and protease-resistant prion protein isoforms in Gerstmann-Sträussler-Scheinker disease with the P102L mutation. PLoS One 2012; 7:e32382. [PMID: 22384235 PMCID: PMC3285667 DOI: 10.1371/journal.pone.0032382] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Accepted: 01/29/2012] [Indexed: 01/09/2023] Open
Abstract
Gerstmann-Sträussler-Scheinker (GSS) disease is a dominantly inherited prion disease associated with point mutations in the Prion Protein gene. The most frequent mutation associated with GSS involves a proline-to-leucine substitution at residue 102 of the prion protein, and is characterized by marked variability at clinical, pathological and molecular levels. Previous investigations of GSS P102L have shown that disease-associated pathological prion protein, or PrP(Sc), consists of two main conformers, which under exogenous proteolysis generates a core fragment of 21 kDa and an internal fragment of 8 kDa. Both conformers are detected in subjects with spongiform degeneration, whereas only the 8 kDa fragment is recovered in cases lacking spongiosis. Several studies have reported an exclusive derivation of protease-resistant PrP(Sc) isoforms from the mutated allele; however, more recently, the propagation of protease-resistant wild-type PrP(Sc) has been described. Here we analyze the molecular and pathological phenotype of six GSS P102L cases characterized by the presence of 21 and 8 kDa PrP fragments and two subjects with only the 8 kDa PrP fragment. Using sensitive protein separation techniques and Western blots with antibodies differentially recognizing wild-type and mutant PrP we observed a range of PrP(Sc) allelic conformers, either resistant or sensitive to protease treatment in all investigated subjects. Additionally, tissue deposition of protease-sensitive wild-type PrP(Sc) molecules was seen by conventional PrP immunohistochemistry and paraffin-embedded tissue blot. Our findings enlarge the spectrum of conformational allelic PrP(Sc) quasispecies propagating in GSS P102L thus providing a molecular support to the spectrum of disease phenotypes, and, in addition, impact the diagnostic role of PrP immunohistochemistry in prion diseases.
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Affiliation(s)
- Salvatore Monaco
- Department of Neurological, Neuropsychological, Morphological and Motor Sciences, University of Verona, Verona, Italy.
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Watts JC, Stöhr J, Bhardwaj S, Wille H, Oehler A, DeArmond SJ, Giles K, Prusiner SB. Protease-resistant prions selectively decrease Shadoo protein. PLoS Pathog 2011; 7:e1002382. [PMID: 22163178 PMCID: PMC3219722 DOI: 10.1371/journal.ppat.1002382] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 10/04/2011] [Indexed: 11/30/2022] Open
Abstract
The central event in prion diseases is the conformational conversion of the cellular prion protein (PrPC) into PrPSc, a partially protease-resistant and infectious conformer. However, the mechanism by which PrPSc causes neuronal dysfunction remains poorly understood. Levels of Shadoo (Sho), a protein that resembles the flexibly disordered N-terminal domain of PrPC, were found to be reduced in the brains of mice infected with the RML strain of prions [1], implying that Sho levels may reflect the presence of PrPSc in the brain. To test this hypothesis, we examined levels of Sho during prion infection using a variety of experimental systems. Sho protein levels were decreased in the brains of mice, hamsters, voles, and sheep infected with different natural and experimental prion strains. Furthermore, Sho levels were decreased in the brains of prion-infected, transgenic mice overexpressing Sho and in infected neuroblastoma cells. Time-course experiments revealed that Sho levels were inversely proportional to levels of protease-resistant PrPSc. Membrane anchoring and the N-terminal domain of PrP both influenced the inverse relationship between Sho and PrPSc. Although increased Sho levels had no discernible effect on prion replication in mice, we conclude that Sho is the first non-PrP marker specific for prion disease. Additional studies using this paradigm may provide insight into the cellular pathways and systems subverted by PrPSc during prion disease. Shadoo is a protein that resembles the prion protein, which causes prion diseases such as Creutzfeldt-Jakob disease in humans and “mad cow” disease. In this paper, we demonstrate that during prion disease in animals, levels of Shadoo were reduced in the brain and correlated with levels of infectious prions. This phenomenon occurred following infection with 14 different prion strains but was not observed following the accumulation of other aggregated proteins, including those that cause Alzheimer's disease and Parkinson's disease. Thus, Shadoo levels in the brain are a specific indicator of prion disease status, and it may be possible to exploit this observation for diagnostic purposes. Although we show that Shadoo itself is unlikely to influence prion disease, using Shadoo as a tool to probe the biology of prions may be a useful strategy for deciphering how prions damage the brain.
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Affiliation(s)
- Joel C. Watts
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, United States of America
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, United States of America
| | - Sumita Bhardwaj
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, United States of America
| | - Holger Wille
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, United States of America
- Department of Neurology, University of California, San Francisco, San Francisco, California, United States of America
| | - Abby Oehler
- Department of Pathology, University of California, San Francisco, San Francisco, California, United States of America
| | - Stephen J. DeArmond
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, United States of America
- Department of Pathology, University of California, San Francisco, San Francisco, California, United States of America
| | - Kurt Giles
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, United States of America
- Department of Neurology, University of California, San Francisco, San Francisco, California, United States of America
| | - Stanley B. Prusiner
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California, United States of America
- Department of Neurology, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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Abstract
Prions are self-replicating proteins that can cause neurodegenerative disorders such as bovine spongiform encephalopathy (also known as mad cow disease). Aberrant conformations of prion proteins accumulate in the central nervous system, causing spongiform changes in the brain and eventually death. Since the inception of the prion hypothesis - which states that misfolded proteins are the infectious agents that cause these diseases - researchers have sought to generate infectious proteins from defined components in the laboratory with varying degrees of success. Here, we discuss several recent studies that have produced an array of novel prion strains in vitro that exhibit increasingly high titres of infectivity. These advances promise unprecedented insight into the structure of prions and the mechanisms by which they originate and propagate.
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Affiliation(s)
- David W. Colby
- Department of Chemical Engineering, University of Delaware, USA
| | - Stanley B. Prusiner
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, USA
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Kim C, Haldiman T, Cohen Y, Chen W, Blevins J, Sy MS, Cohen M, Safar JG. Protease-sensitive conformers in broad spectrum of distinct PrPSc structures in sporadic Creutzfeldt-Jakob disease are indicator of progression rate. PLoS Pathog 2011; 7:e1002242. [PMID: 21931554 PMCID: PMC3169556 DOI: 10.1371/journal.ppat.1002242] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 07/12/2011] [Indexed: 11/21/2022] Open
Abstract
The origin, range, and structure of prions causing the most common human prion disease, sporadic Creutzfeldt-Jakob disease (sCJD), are largely unknown. To investigate the molecular mechanism responsible for the broad phenotypic variability of sCJD, we analyzed the conformational characteristics of protease-sensitive and protease-resistant fractions of the pathogenic prion protein (PrPSc) using novel conformational methods derived from a conformation-dependent immunoassay (CDI). In 46 brains of patients homozygous for polymorphisms in the PRNP gene and exhibiting either Type 1 or Type 2 western blot pattern of the PrPSc, we identified an extensive array of PrPSc structures that differ in protease sensitivity, display of critical domains, and conformational stability. Surprisingly, in sCJD cases homozygous for methionine or valine at codon 129 of the PRNP gene, the concentration and stability of protease-sensitive conformers of PrPSc correlated with progression rate of the disease. These data indicate that sCJD brains exhibit a wide spectrum of PrPSc structural states, and accordingly argue for a broad spectrum of prion strains coding for different phenotypes. The link between disease duration, levels, and stability of protease-sensitive conformers of PrPSc suggests that these conformers play an important role in the pathogenesis of sCJD. Sporadic Creutzfeldt-Jakob disease (sCJD) is the most common human prion disease worldwide. This neurodegenerative disease, which is transmissible and invariably fatal, is characterized by the accumulation of an abnormally folded isoform (PrPSc) of a host-encoded protein (PrPC), predominantly in the brain. Most researchers believe that PrPSc is the infectious agent and five or six subtypes of sCJD have been identified. Whether or not these subtypes represent distinct strains of sCJD prions is debated in the context of the extraordinary variability of sCJD phenotypes, frequent co-occurrence of different PrPSc fragments in the same brain, and the fact that up to 90% of protease-sensitive PrPSc eludes the conventional analysis because it is destroyed by protease treatment. Using novel conformational methods, we identified within each clinical and pathological category an array of PrPSc structures that differ in protease-sensitivity, display of critical domains, and conformational stability. Each of these features offers evidence of a distinct conformation. The link between the rate at which the disease progresses, on the one hand, and the concentration and stability of protease-sensitive conformers of PrPSc on the other, suggests that these conformers play an important role in how the disease originates and progresses.
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Affiliation(s)
- Chae Kim
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- National Prion Disease Pathology Surveillance Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Tracy Haldiman
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Yvonne Cohen
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- National Prion Disease Pathology Surveillance Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Wei Chen
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- National Prion Disease Pathology Surveillance Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Janis Blevins
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- National Prion Disease Pathology Surveillance Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Man-Sun Sy
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Mark Cohen
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- National Prion Disease Pathology Surveillance Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jiri G. Safar
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- National Prion Disease Pathology Surveillance Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Safar JG, Giles K, Lessard P, Letessier F, Patel S, Serban A, DeArmond SJ, Prusiner SB. Conserved properties of human and bovine prion strains on transmission to guinea pigs. J Transl Med 2011; 91:1326-36. [PMID: 21727894 PMCID: PMC3164925 DOI: 10.1038/labinvest.2011.89] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The first transmissions of human prion diseases to rodents used guinea pigs (Gps, Cavia porcellus). Later, transgenic mice expressing human or chimeric human/mouse PrP replaced Gps, but the small size of the mouse limits some investigations. To investigate the fidelity of strain-specific prion transmission to Gps, we inoculated 'type 1' and 'type 2' prion strains into Gps, and we measured the incubation times and determined the strain-specified size of the unglycosylated, protease-resistant (r) PrP(Sc) fragment. Prions passaged once in Gps from cases of sporadic (s) Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker (GSS) disease caused by the P102L mutation were used, as well as human prions from a variant (v) CJD case, bovine prions from bovine spongiform encephalopathy (BSE) and mouse-passaged scrapie prions. Variant CJD and BSE prions transmitted to all the inoculated Gps with incubation times of 367 ± 4 and 436 ± 28 days, respectively. On second passage in Gps, vCJD and BSE prions caused disease in 287 ± 4 and 310 ± 4 days, whereas sCJD and GSS prions transmitted in 237 ± 4 and 279 ± 19 days, respectively. Although hamster Sc237 prions transmitted to two of three Gps after 574 and 792 days, mouse-passaged RML and 301V prion strains, the latter derived from BSE prions, failed to transmit disease to Gps. Those Gps inoculated with vCJD or BSE prions exhibited 'type 2' unglycosylated, rPrP(Sc) (19 kDa), whereas those receiving sCJD or GSS prions displayed 'type 1' prions (21 kDa), as determined by western blotting. Such strain-specific properties were maintained in Gps as well as mice expressing a chimeric human/mouse transgene. Gps may prove particularly useful in further studies of novel human prions such as those causing vCJD.
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Affiliation(s)
- Jiri G. Safar
- Institute for Neurodegenerative Diseases, University of California, San Francisco
,Department of Neurology, University of California, San Francisco
| | - Kurt Giles
- Institute for Neurodegenerative Diseases, University of California, San Francisco
,Department of Neurology, University of California, San Francisco
| | - Pierre Lessard
- Institute for Neurodegenerative Diseases, University of California, San Francisco
| | - Frederic Letessier
- Institute for Neurodegenerative Diseases, University of California, San Francisco
| | - Smita Patel
- Institute for Neurodegenerative Diseases, University of California, San Francisco
| | - Ana Serban
- Institute for Neurodegenerative Diseases, University of California, San Francisco
| | - Stephen J. DeArmond
- Institute for Neurodegenerative Diseases, University of California, San Francisco
,Department of Pathology, University of California, San Francisco
| | - Stanley B. Prusiner
- Institute for Neurodegenerative Diseases, University of California, San Francisco
,Department of Neurology, University of California, San Francisco
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Jeffrey M, McGovern G, Chambers EV, King D, González L, Manson JC, Ghetti B, Piccardo P, Barron RM. Mechanism of PrP-amyloid formation in mice without transmissible spongiform encephalopathy. Brain Pathol 2011; 22:58-66. [PMID: 21645162 DOI: 10.1111/j.1750-3639.2011.00508.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Gerstmann-Sträussler-Scheinker (GSS) P102L disease is a familial form of a transmissible spongiform encephalopathy (TSE) that can present with or without vacuolation of neuropil. Inefficient disease transmission into 101LL transgenic mice was previously observed from GSS P102L without vacuolation. However, several aged, healthy mice had large plaques composed of abnormal prion protein (PrP(d)). Here we perform the ultrastructural characterization of such plaques and compare them with PrP(d) aggregates found in TSE caused by an infectious mechanism. PrP(d) plaques in 101LL mice varied in maturity, with some being composed of deposits without visible amyloid fibrils. PrP(d) was present on cell membranes in the vicinity of all types of plaques. In contrast to the unicentric plaques seen in infectious murine scrapie, the plaques seen in the current model were multicentric and were initiated by protofibrillar forms of PrP(d) situated on oligodendroglia, astrocytes and neuritic cell membranes. We speculate that the initial conversion process leading to plaque formation begins with membrane-bound PrP(C) but that subsequent fibrillization does not require membrane attachment. We also observed that the membrane alterations consistently seen in murine scrapie and other infectious TSEs were not present in 101LL mice with plaques, suggesting differences in the pathogenesis of these conditions.
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Affiliation(s)
- Martin Jeffrey
- Animal Health Veterinary Laboratories Agency, Pentlands Science Park, Bush Loan Penicuik, Midlothian, UK.
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Wadsworth JDF, Asante EA, Collinge J. Review: contribution of transgenic models to understanding human prion disease. Neuropathol Appl Neurobiol 2011; 36:576-97. [PMID: 20880036 PMCID: PMC3017745 DOI: 10.1111/j.1365-2990.2010.01129.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Transgenic mice expressing human prion protein in the absence of endogenous mouse prion protein faithfully replicate human prions. These models reproduce all of the key features of human disease, including long clinically silent incubation periods prior to fatal neurodegeneration with neuropathological phenotypes that mirror human prion strain diversity. Critical contributions to our understanding of human prion disease pathogenesis and aetiology have only been possible through the use of transgenic mice. These models have provided the basis for the conformational selection model of prion transmission barriers and have causally linked bovine spongiform encephalopathy with variant Creutzfeldt-Jakob disease. In the future these models will be essential for evaluating newly identified potentially zoonotic prion strains, for validating effective methods of prion decontamination and for developing effective therapeutic treatments for human prion disease.
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Affiliation(s)
- J D F Wadsworth
- MRC Prion Unit and Department of Neurodegenerative Disease, Institute of Neurology, University College London, National Hospital for Neurology and Neurosurgery, London, UK.
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Wadsworth JDF, Collinge J. Molecular pathology of human prion disease. Acta Neuropathol 2011; 121:69-77. [PMID: 20694796 PMCID: PMC3015177 DOI: 10.1007/s00401-010-0735-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 07/29/2010] [Accepted: 07/30/2010] [Indexed: 11/28/2022]
Abstract
Human prion diseases are associated with a range of clinical presentations and are classified by both clinicopathological syndrome and aetiology with sub-classification according to molecular criteria. Considerable experimental evidence suggests that phenotypic diversity in human prion disease relates in significant part to the existence of distinct human prion strains encoded by abnormal PrP isoforms with differing physicochemical properties. To date, however, the conformational repertoire of pathological isoforms of wild-type human PrP and the various forms of mutant human PrP has not been fully defined. Efforts to produce a unified international classification of human prion disease are still ongoing. The ability of genetic background to influence prion strain selection together with knowledge of numerous other factors that may influence clinical and neuropathological presentation strongly emphasises the requirement to identify distinct human prion strains in appropriate transgenic models, where host genetic variability and other modifiers of phenotype are removed. Defining how many human prion strains exist allied with transgenic modelling of potentially zoonotic prion strains will inform on how many human infections may have an animal origin. Understanding these relationships will have direct translation to protecting public health.
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Affiliation(s)
- Jonathan D. F. Wadsworth
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG UK
| | - John Collinge
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG UK
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Abstract
The discovery of infectious proteins, denoted prions, was unexpected. After much debate over the chemical basis of heredity, resolution of this issue began with the discovery that DNA, not protein, from pneumococcus was capable of genetically transforming bacteria (Avery et al. 1944). Four decades later, the discovery that a protein could mimic viral and bacterial pathogens with respect to the transmission of some nervous system diseases (Prusiner 1982) met with great resistance. Overwhelming evidence now shows that Creutzfeldt-Jakob disease (CJD) and related disorders are caused by prions. The prion diseases are characterized by neurodegeneration and lethality. In mammals, prions reproduce by recruiting the normal, cellular isoform of the prion protein (PrP(C)) and stimulating its conversion into the disease-causing isoform (PrP(Sc)). PrP(C) and PrP(Sc) have distinct conformations: PrP(C) is rich in α-helical content and has little β-sheet structure, whereas PrP(Sc) has less α-helical content and is rich in β-sheet structure (Pan et al. 1993). The conformational conversion of PrP(C) to PrP(Sc) is the fundamental event underlying prion diseases. In this article, we provide an introduction to prions and the diseases they cause.
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Affiliation(s)
- David W Colby
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California 94143, USA
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Isolation of proteinase K-sensitive prions using pronase E and phosphotungstic acid. PLoS One 2010; 5:e15679. [PMID: 21187933 PMCID: PMC3004958 DOI: 10.1371/journal.pone.0015679] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 11/21/2010] [Indexed: 11/25/2022] Open
Abstract
Disease-related prion protein, PrPSc, is classically distinguished from its normal cellular precursor, PrPC, by its detergent insolubility and partial resistance to proteolysis. Molecular diagnosis of prion disease typically relies upon detection of protease-resistant fragments of PrPSc using proteinase K, however it is now apparent that the majority of disease-related PrP and indeed prion infectivity may be destroyed by this treatment. Here we report that digestion of RML prion-infected mouse brain with pronase E, followed by precipitation with sodium phosphotungstic acid, eliminates the large majority of brain proteins, including PrPC, while preserving >70% of infectious prion titre. This procedure now allows characterization of proteinase K-sensitive prions and investigation of their clinical relevance in human and animal prion disease without being confounded by contaminating PrPC.
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Choi YP, Gröner A, Ironside JW, Head MW. Comparison of the level, distribution and form of disease-associated prion protein in variant and sporadic Creutzfeldt-Jakob diseased brain using conformation-dependent immunoassay and Western blot. J Gen Virol 2010; 92:727-32. [PMID: 21123539 DOI: 10.1099/vir.0.026948-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Disease-associated prion protein (PrP(Sc)) can be distinguished from the cellular isoform (PrP(C)) by conformation-dependent immunoassay (CDI). This technique exploits the presence of an epitope, accessible in PrP(C), but only unmasked by denaturation in PrP(Sc). In this study, we investigated PrP(Sc) in different brain regions in variant and sporadic Creutzfeldt-Jakob disease (CJD) by using CDI, and directly compared the results with those obtained using the more commonly employed protease digestion and Western blotting. In general, there was good agreement between the results, although there were certain discrepancies in relative abundance when the regional distribution in variant CJD cases was considered. The results largely confirmed the previously described targeting of different brain regions by variant and sporadic CJD. Additionally, the combination of protease digestion and CDI detection demonstrated, for the first time, the presence of PrP(Sc) in variant CJD brains that is susceptible to proteolysis under standard conditions.
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Affiliation(s)
- Young Pyo Choi
- National CJD Surveillance Unit, School of Molecular & Clinical Medicine (Pathology), University of Edinburgh, Edinburgh, UK
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Li L, Napper S, Cashman NR. Immunotherapy for prion diseases: opportunities and obstacles. Immunotherapy 2010; 2:269-82. [PMID: 20635933 DOI: 10.2217/imt.10.3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) represent a unique form of infectious disease based on the misfolding of a self-protein into a pathological conformation. While other human diseases are also attributed to protein misfolding, the TSEs are unique in their zoonotic potential and iatrogenic infectivity. These characteristics are of particular importance in the aftermath of the UK bovine spongiform encephalopathy (BSE) outbreak due to the dual concerns that a subpopulation of individuals exposed to the infectious agent may be serving as asymptomatic carriers, and that TSEs of other food animals may also threaten human health. These potentials, in addition to the ongoing baseline of familial and sporadic human prion diseases, necessitate development of effective treatment options. While TSEs represent a novel paradigm of infection, there is nevertheless the opportunity to apply traditional approaches of medicine for disease treatment and prevention, including vaccines for immunotherapy and immunoprophylaxis. However, vaccine development for TSEs is complicated by the challenges and potential dangers associated with induction of immune responses to a self-epitope, as well as the obstacles to treatment of a chronic infection through immunotherapy. The ongoing threat of TSEs to human health, together with the opportunity to apply information emerging from these investigations to other protein misfolding disorders, justifies the efforts required to overcome these obstacles.
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Affiliation(s)
- Li Li
- University of British Columbia & Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
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A new method for the characterization of strain-specific conformational stability of protease-sensitive and protease-resistant PrPSc. PLoS One 2010; 5:e12723. [PMID: 20856860 PMCID: PMC2939050 DOI: 10.1371/journal.pone.0012723] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 08/02/2010] [Indexed: 11/24/2022] Open
Abstract
Although proteinacious in nature, prions exist as strains with specific self-perpetuating biological properties. Prion strains are thought to be associated with different conformers of PrPSc, a disease-associated isoform of the host-encoded cellular protein (PrPC). Molecular strain typing approaches have been developed which rely on the characterization of protease-resistant PrPSc. However, PrPSc is composed not only of protease-resistant but also of protease-sensitive isoforms. The aim of this work was to develop a protocol for the molecular characterization of both, protease-resistant and protease-sensitive PrPSc aggregates. We first set up experimental conditions which allowed the most advantageous separation of PrPC and PrPSc by means of differential centrifugation. The conformational solubility and stability assay (CSSA) was then developed by measuring PrPSc solubility as a function of increased exposure to GdnHCl. Brain homogenates from voles infected with human and sheep prion isolates were analysed by CSSA and showed strain-specific conformational stabilities, with mean [GdnHCl]1/2 values ranging from 1.6 M for MM2 sCJD to 2.1 for scrapie and to 2.8 M for MM1/MV1 sCJD and E200K gCJD. Interestingly, the rank order of [GdnHCl]1/2 values observed in the human and sheep isolates used as inocula closely matched those found following transmission in voles, being MM1 sCJD the most resistant (3.3 M), followed by sheep scrapie (2.2 M) and by MM2 sCJD (1.6 M). In order to test the ability of CSSA to characterise protease-sensitive PrPSc, we analysed sheep isolates of Nor98 and compared them to classical scrapie isolates. In Nor98, insoluble PrPSc aggregates were mainly protease-sensitive and showed a conformational stability much lower than in classical scrapie. Our results show that CSSA is able to reveal strain-specified PrPSc conformational stabilities of protease-resistant and protease-sensitive PrPSc and that it is a valuable tool for strain typing in natural hosts, such as humans and sheep.
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Choi JK, Jeon YC, Lee DW, Oh JM, Lee HP, Jeong BH, Carp RI, Koh YH, Kim YS. A Drosophila model of GSS syndrome suggests defects in active zones are responsible for pathogenesis of GSS syndrome. Hum Mol Genet 2010; 19:4474-89. [PMID: 20829230 DOI: 10.1093/hmg/ddq379] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We have established a Drosophila model of Gerstmann-Sträussler-Scheinker (GSS) syndrome by expressing mouse prion protein (PrP) having leucine substitution at residue 101 (MoPrP(P101L)). Flies expressing MoPrP(P101L), but not wild-type MoPrP (MoPrP(3F4)), showed severe defects in climbing ability and early death. Expressed MoPrP(P101L) in Drosophila was differentially glycosylated, localized at the synaptic terminals and mainly present as deposits in adult brains. We found that behavioral defects and early death of MoPrP(P101L) flies were not due to Caspase 3-dependent programmed cell death signaling. In addition, we found that Type 1 glutamatergic synaptic boutons in larval neuromuscular junctions of MoPrP(P101L) flies showed significantly increased numbers of satellite synaptic boutons. Furthermore, the amount of Bruchpilot and Discs large in MoPrP(P101L) flies was significantly reduced. Brains from scrapie-infected mice showed significantly decreased ELKS, an active zone matrix marker compared with those of age-matched control mice. Thus, altered active zone structures at the molecular level may be involved in the pathogenesis of GSS syndrome in Drosophila and scrapie-infected mice.
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Affiliation(s)
- Jin-Kyu Choi
- Ilsong Institute of Life Science, Hallym University, 1605-4 Gwanyangdong Dongangu, Anyang, Gyeonggi-Do, Republic of Korea
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The hydrophobic core region governs mutant prion protein aggregation and intracellular retention. Biochem J 2010; 430:477-86. [DOI: 10.1042/bj20100615] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Approx. 15% of human prion diseases have a pattern of autosomal dominant inheritance, and are linked to mutations in the gene encoding PrP (prion protein), a GPI (glycosylphosphatidylinositol)-anchored protein whose function is not clear. The cellular mechanisms by which PrP mutations cause disease are also not known. Soon after synthesis in the ER (endoplasmic reticulum), several mutant PrPs misfold and become resistant to phospholipase cleavage of their GPI anchor. The biosynthetic maturation of the misfolded molecules in the ER is delayed and, during transit in the secretory pathway, they form detergent-insoluble and protease-resistant aggregates, suggesting that intracellular PrP aggregation may play a pathogenic role. We have investigated the consequence of deleting residues 114–121 within the hydrophobic core of PrP on the aggregation and cellular localization of two pathogenic mutants that accumulate in the ER and Golgi apparatus. Compared with their full-length counterparts, the deleted molecules formed smaller protease-sensitive aggregates and were more efficiently transported to the cell surface and released by phospholipase cleavage. These results indicate that mutant PrP aggregation and intracellular retention are closely related and depend critically on the integrity of the hydrophobic core. The discovery that Δ114–121 counteracts misfolding and improves the cellular trafficking of mutant PrP provides an unprecedented model for assessing the role of intracellular aggregation in the pathogenesis of prion diseases.
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Damo SM, Phillips AH, Young AL, Li S, Woods VL, Wemmer DE. Probing the conformation of a prion protein fibril with hydrogen exchange. J Biol Chem 2010; 285:32303-11. [PMID: 20679344 DOI: 10.1074/jbc.m110.114504] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A fragment of the prion protein, PrP(89-143, P101L), bearing a mutation implicated in familial prion disease, forms fibrils that have been shown to induce prion disease when injected intracerebrally into transgenic mice expressing full-length PrP containing the P101L mutation. In this study, we utilize amide hydrogen exchange measurements to probe the organization of the peptide in its fibrillar form. We determined the extent of hydrogen exchange first by tandem proteolysis, liquid chromatography, and mass spectrometry (HXMS) and then by exchange-quenched NMR. Although single amide resolution is afforded by NMR measurements, HXMS is well suited to the study of natural prions because it does not require labeling with NMR active isotopes. Thus, natural prions obtained from infected animals can be compared with model systems such as PrP(89-143, P101L) studied here. In our study, we find two segments of sequence that display a high level of protection from exchange, residues 102-109 and 117-136. In addition, there is a region that displays exchange behavior consistent with the presence of a conformationally heterogeneous turn. We discuss our data with respect to several structural models proposed for infectious PrP aggregates and highlight HXMS as one of the few techniques well suited to studying natural prions.
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Affiliation(s)
- Steven M Damo
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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