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Simmons SM, Bartz JC. Strain-Specific Targeting and Destruction of Cells by Prions. BIOLOGY 2024; 13:57. [PMID: 38275733 PMCID: PMC10813089 DOI: 10.3390/biology13010057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/11/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024]
Abstract
Prion diseases are caused by the disease-specific self-templating infectious conformation of the host-encoded prion protein, PrPSc. Prion strains are operationally defined as a heritable phenotype of disease under controlled conditions. One of the hallmark phenotypes of prion strain diversity is tropism within and between tissues. A defining feature of prion strains is the regional distribution of PrPSc in the CNS. Additionally, in both natural and experimental prion disease, stark differences in the tropism of prions in secondary lymphoreticular system tissues occur. The mechanism underlying prion tropism is unknown; however, several possible hypotheses have been proposed. Clinical target areas are prion strain-specific populations of neurons within the CNS that are susceptible to neurodegeneration following the replication of prions past a toxic threshold. Alternatively, the switch from a replicative to toxic form of PrPSc may drive prion tropism. The normal form of the prion protein, PrPC, is required for prion formation. More recent evidence suggests that it can mediate prion and prion-like disease neurodegeneration. In vitro systems for prion formation have indicated that cellular cofactors contribute to prion formation. Since these cofactors can be strain specific, this has led to the hypothesis that the distribution of prion formation cofactors can influence prion tropism. Overall, there is evidence to support several mechanisms of prion strain tropism; however, a unified theory has yet to emerge.
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Affiliation(s)
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE 68178, USA;
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2
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Beta-endoproteolysis of the cellular prion protein by dipeptidyl peptidase-4 and fibroblast activation protein. Proc Natl Acad Sci U S A 2023; 120:e2209815120. [PMID: 36574660 PMCID: PMC9910601 DOI: 10.1073/pnas.2209815120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The cellular prion protein (PrPC) converts to alternatively folded pathogenic conformations (PrPSc) in prion infections and binds neurotoxic oligomers formed by amyloid-β α-synuclein, and tau. β-Endoproteolysis, which splits PrPC into N- and C-terminal fragments (N2 and C2, respectively), is of interest because a protease-resistant, C2-sized fragment (C2Sc) accumulates in the brain during prion infections, seemingly comprising the majority of PrPSc at disease endpoint in mice. However, candidates for the underlying proteolytic mechanism(s) remain unconfirmed in vivo. Here, a cell-based screen of protease inhibitors unexpectedly linked type II membrane proteins of the S9B serine peptidase subfamily to PrPC β-cleavage. Overexpression experiments in cells and assays with recombinant proteins confirmed that fibroblast activation protein (FAP) and its paralog, dipeptidyl peptidase-4 (DPP4), cleave directly at multiple sites within PrPC's N-terminal domain. For wild-type mouse and human PrPC substrates expressed in cells, the rank orders of activity were human FAP ~ mouse FAP > mouse DPP4 > human DPP4 and human FAP > mouse FAP > mouse DPP4 >> human DPP4, respectively. C2 levels relative to total PrPC were reduced in several tissues from FAP-null mice, and, while knockout of DPP4 lacked an analogous effect, the combined DPP4/FAP inhibitor linagliptin, but not the FAP-specific inhibitor SP-13786, reduced C2Sc and total PrPSc levels in two murine cell-based models of prion infections. Thus, the net activity of the S9B peptidases FAP and DPP4 and their cognate inhibitors/modulators affect the physiology and pathogenic potential of PrPC.
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3
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Igel A, Fornara B, Rezaei H, Béringue V. Prion assemblies: structural heterogeneity, mechanisms of formation, and role in species barrier. Cell Tissue Res 2022; 392:149-166. [PMID: 36399162 PMCID: PMC10113350 DOI: 10.1007/s00441-022-03700-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/03/2022] [Indexed: 11/19/2022]
Abstract
AbstractPrions are proteinaceous pathogens responsible for a wide range of neurodegenerative diseases in animal and human. Prions are formed from misfolded, ß-sheet rich, and aggregated conformers (PrPSc) of the host-encoded prion protein (PrPC). Prion replication stems from the capacity of PrPSc to self-replicate by templating PrPC conversion and polymerization. The question then arises about the molecular mechanisms of prion replication, host invasion, and capacity to contaminate other species. Studying these mechanisms has gained in recent years further complexity with evidence that PrPSc is a pleiomorphic protein. There is indeed compelling evidence for PrPSc structural heterogeneity at different scales: (i) within prion susceptible host populations with the existence of different strains with specific biological features due to different PrPSc conformers, (ii) within a single infected host with the co-propagation of different strains, and (iii) within a single strain with evidence for co-propagation of PrPSc assemblies differing in their secondary to quaternary structure. This review summarizes current knowledge of prion assembly heterogeneity, potential mechanisms of formation during the replication process, and importance when crossing the species barrier.
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4
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Mercer RCC, Harris DA. Mechanisms of prion-induced toxicity. Cell Tissue Res 2022; 392:81-96. [PMID: 36070155 DOI: 10.1007/s00441-022-03683-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/30/2022] [Indexed: 11/02/2022]
Abstract
Prion diseases are devastating neurodegenerative diseases caused by the structural conversion of the normally benign prion protein (PrPC) to an infectious, disease-associated, conformer, PrPSc. After decades of intense research, much is known about the self-templated prion conversion process, a phenomenon which is now understood to be operative in other more common neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. In this review, we provide the current state of knowledge concerning a relatively poorly understood aspect of prion diseases: mechanisms of neurotoxicity. We provide an overview of proposed functions of PrPC and its interactions with other extracellular proteins in the central nervous system, in vivo and in vitro models used to delineate signaling events downstream of prion propagation, the application of omics technologies, and the emerging appreciation of the role played by non-neuronal cell types in pathogenesis.
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Affiliation(s)
- Robert C C Mercer
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA.
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5
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Mays CE, Trinh THT, Telling G, Kang HE, Ryou C. Endoproteolysis of cellular prion protein by plasmin hinders propagation of prions. Front Mol Neurosci 2022; 15:990136. [PMID: 36117913 PMCID: PMC9478470 DOI: 10.3389/fnmol.2022.990136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/15/2022] [Indexed: 01/21/2023] Open
Abstract
Many questions surround the underlying mechanism for the differential metabolic processing observed for the prion protein (PrP) in healthy and prion-infected mammals. Foremost, the physiological α-cleavage of PrP interrupts a region critical for both toxicity and conversion of cellular PrP (PrP C ) into its misfolded pathogenic isoform (PrP Sc ) by generating a glycosylphosphatidylinositol (GPI)-anchored C1 fragment. During prion diseases, alternative β-cleavage of PrP becomes prominent, producing a GPI-anchored C2 fragment with this particular region intact. It remains unexplored whether physical up-regulation of α-cleavage can inhibit disease progression. Furthermore, several pieces of evidence indicate that a disintegrin and metalloproteinase (ADAM) 10 and ADAM17 play a much smaller role in the α-cleavage of PrP C than originally believed, thus presenting the need to identify the primary protease(s) responsible. For this purpose, we characterized the ability of plasmin to perform PrP α-cleavage. Then, we conducted functional assays using protein misfolding cyclic amplification (PMCA) and prion-infected cell lines to clarify the role of plasmin-mediated α-cleavage during prion propagation. Here, we demonstrated an inhibitory role of plasmin for PrP Sc formation through PrP α-cleavage that increased C1 fragments resulting in reduced prion conversion compared with non-treated PMCA and cell cultures. The reduction of prion infectious titer in the bioassay of plasmin-treated PMCA material also supported the inhibitory role of plasmin on PrP Sc replication. Our results suggest that plasmin-mediated endoproteolytic cleavage of PrP may be an important event to prevent prion propagation.
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Affiliation(s)
- Charles E. Mays
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Trang H. T. Trinh
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, South Korea,Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, South Korea
| | - Glenn Telling
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States,Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States,Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Hae-Eun Kang
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States,Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States,Reference Laboratory for Chronic Wasting Disease (CWD), Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Gimcheon, South Korea,Hae-Eun Kang,
| | - Chongsuk Ryou
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States,Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, South Korea,Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, South Korea,Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States,*Correspondence: Chongsuk Ryou,
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6
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Mehrabian M, Wang X, Eid S, Yan BQ, Grinberg M, Siegner M, Sackmann C, Sulman M, Zhao W, Williams D, Schmitt-Ulms G. Cardiac glycoside-mediated turnover of Na, K-ATPases as a rational approach to reducing cell surface levels of the cellular prion protein. PLoS One 2022; 17:e0270915. [PMID: 35776750 PMCID: PMC9249225 DOI: 10.1371/journal.pone.0270915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 06/17/2022] [Indexed: 01/16/2023] Open
Abstract
It is widely anticipated that a reduction of brain levels of the cellular prion protein (PrPC) can prolong survival in a group of neurodegenerative diseases known as prion diseases. To date, efforts to decrease steady-state PrPC levels by targeting this protein directly with small molecule drug-like compounds have largely been unsuccessful. Recently, we reported Na,K-ATPases to reside in immediate proximity to PrPC in the brain, unlocking an opportunity for an indirect PrPC targeting approach that capitalizes on the availability of potent cardiac glycosides (CGs). Here, we report that exposure of human co-cultures of neurons and astrocytes to non-toxic nanomolar levels of CGs causes profound reductions in PrPC levels. The mechanism of action underpinning this outcome relies primarily on a subset of CGs engaging the ATP1A1 isoform, one of three α subunits of Na,K-ATPases expressed in brain cells. Upon CG docking to ATP1A1, the ligand receptor complex, and PrPC along with it, is internalized by the cell. Subsequently, PrPC is channeled to the lysosomal compartment where it is digested in a manner that can be rescued by silencing the cysteine protease cathepsin B. These data signify that the repurposing of CGs may be beneficial for the treatment of prion disorders.
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Affiliation(s)
- Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Xinzhu Wang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Shehab Eid
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Bei Qi Yan
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Mark Grinberg
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
| | - Murdock Siegner
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Christopher Sackmann
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
| | - Muhammad Sulman
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
| | - Wenda Zhao
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Declan Williams
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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7
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Castle AR, Wohlgemuth S, Arce L, Westaway D. Investigating CRISPR/Cas9 gene drive for production of disease-preventing prion gene alleles. PLoS One 2022; 17:e0269342. [PMID: 35671288 PMCID: PMC9173614 DOI: 10.1371/journal.pone.0269342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 05/18/2022] [Indexed: 11/29/2022] Open
Abstract
Prion diseases are a group of fatal neurodegenerative disorders that includes chronic wasting disease, which affects cervids and is highly transmissible. Given that chronic wasting disease prevalence exceeds 30% in some endemic areas of North America, and that eventual transmission to other mammalian species, potentially including humans, cannot be ruled out, novel control strategies beyond population management via hunting and/or culling must be investigated. Prion diseases depend upon post-translational conversion of the cellular prion protein, encoded by the Prnp gene, into a disease-associated conformation; ablation of cellular prion protein expression, which is generally well-tolerated, eliminates prion disease susceptibility entirely. Inspired by demonstrations of gene drive in caged mosquito species, we aimed to test whether a CRISPR/Cas9-based gene drive mechanism could, in principle, promote the spread of a null Prnp allele among mammalian populations. First, we showed that transient co-expression of Cas9 and Prnp-directed guide RNAs in RK13 cells generates indels within the Prnp open-reading frame, indicating that repair of Cas9-induced double-strand breaks by non-homologous end-joining had taken place. Second, we integrated a ~1.2 kb donor DNA sequence into the Prnp open-reading frame in N2a cells by homology-directed repair following Cas9-induced cleavages and confirmed that integration occurred precisely in most cases. Third, we demonstrated that electroporation of Cas9/guide RNA ribonucleoprotein complexes into fertilised mouse oocytes resulted in pups with a variety of disruptions to the Prnp open reading frame, with a new coisogenic line of Prnp-null mice obtained as part of this work. However, a technical challenge in obtaining expression of Cas9 in the male germline prevented implementation of a complete gene drive mechanism in mice.
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Affiliation(s)
- Andrew R. Castle
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Serene Wohlgemuth
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Luis Arce
- 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, University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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8
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Daude N, Lau A, Vanni I, Kang SG, Castle AR, Wohlgemuth S, Dorosh L, Wille H, Stepanova M, Westaway D. Prion protein with a mutant N-terminal octarepeat region undergoes cobalamin-dependent assembly into high-molecular weight complexes. J Biol Chem 2022; 298:101770. [PMID: 35271850 PMCID: PMC9010764 DOI: 10.1016/j.jbc.2022.101770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 11/28/2022] Open
Abstract
The cellular prion protein (PrPC) has a C-terminal globular domain and a disordered N-terminal region encompassing five octarepeats (ORs). Encounters between Cu(II) ions and four OR sites produce interchangeable binding geometries; however, the significance of Cu(II) binding to ORs in different combinations is unclear. To understand the impact of specific binding geometries, OR variants were designed that interact with multiple or single Cu(II) ions in specific locked coordinations. Unexpectedly, we found that one mutant produced detergent-insoluble, protease-resistant species in cells in the absence of exposure to the infectious prion protein isoform, scrapie-associated prion protein (PrPSc). Formation of these assemblies, visible as puncta, was reversible and dependent upon medium formulation. Cobalamin (Cbl), a dietary cofactor containing a corrin ring that coordinates a Co3+ ion, was identified as a key medium component, and its effect was validated by reconstitution experiments. Although we failed to find evidence that Cbl interacts with Cu-binding OR regions, we instead noted interactions of Cbl with the PrPC C-terminal domain. We found that some interactions occurred at a binding site of planar tetrapyrrole compounds on the isolated globular domain, but others did not, and N-terminal sequences additionally had a marked effect on their presence and position. Our studies define a conditional effect of Cbl wherein a mutant OR region can act in cis to destabilize a globular domain with a wild type sequence. The unexpected intersection between the properties of PrPSc's disordered region, Cbl, and conformational remodeling events may have implications for understanding sporadic prion disease that does not involve exposure to PrPSc.
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Affiliation(s)
- Nathalie Daude
- Centre for Prions and Protein Folding Diseases, University of Alberta, Canada
| | - Agnes Lau
- Centre for Prions and Protein Folding Diseases, University of Alberta, Canada
| | - Ilaria Vanni
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Sang-Gyun Kang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Canada
| | - Andrew R Castle
- Centre for Prions and Protein Folding Diseases, University of Alberta, Canada
| | - Serene Wohlgemuth
- Centre for Prions and Protein Folding Diseases, University of Alberta, Canada
| | - Lyudmyla Dorosh
- Faculty of Engineering - Electrical & Computer Engineering Dept, University of Alberta, Canada
| | - Holger Wille
- Centre for Prions and Protein Folding Diseases, University of Alberta, Canada; Department of Biochemistry, University of Alberta, Canada
| | - Maria Stepanova
- Faculty of Engineering - Electrical & Computer Engineering Dept, University of Alberta, Canada
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Canada.
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Kim C, Haldiman T, Kang SG, Hromadkova L, Han ZZ, Chen W, Lissemore F, Lerner A, de Silva R, Cohen ML, Westaway D, Safar JG. Distinct populations of highly potent TAU seed conformers in rapidly progressing Alzheimer's disease. Sci Transl Med 2022; 14:eabg0253. [PMID: 34985969 DOI: 10.1126/scitranslmed.abg0253] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Chae Kim
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Tracy Haldiman
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Sang-Gyun Kang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton T6G 2M8, Canada
| | - Lenka Hromadkova
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Zhuang Zhuang Han
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton T6G 2M8, Canada
| | - Wei Chen
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Frances Lissemore
- Department of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Alan Lerner
- Department of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Rohan de Silva
- Reta Lila Weston Institute of Neurological Studies and Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 1PJ, UK
| | - Mark L Cohen
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton T6G 2M8, Canada
| | - Jiri G Safar
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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10
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Membrane Domain Localization and Interaction of the Prion-Family Proteins, Prion and Shadoo with Calnexin. MEMBRANES 2021; 11:membranes11120978. [PMID: 34940479 PMCID: PMC8704586 DOI: 10.3390/membranes11120978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 11/30/2022]
Abstract
The cellular prion protein (PrPC) is renowned for its infectious conformational isoform PrPSc, capable of templating subsequent conversions of healthy PrPCs and thus triggering the group of incurable diseases known as transmissible spongiform encephalopathies. Besides this mechanism not being fully uncovered, the protein’s physiological role is also elusive. PrPC and its newest, less understood paralog Shadoo are glycosylphosphatidylinositol-anchored proteins highly expressed in the central nervous system. While they share some attributes and neuroprotective actions, opposing roles have also been reported for the two; however, the amount of data about their exact functions is lacking. Protein–protein interactions and membrane microdomain localizations are key determinants of protein function. Accurate identification of these functions for a membrane protein, however, can become biased due to interactions occurring during sample processing. To avoid such artifacts, we apply a non-detergent-based membrane-fractionation approach to study the prion protein and Shadoo. We show that the two proteins occupy similarly raft and non-raft membrane fractions when expressed in N2a cells and that both proteins pull down the chaperone calnexin in both rafts and non-rafts. These indicate their possible binding to calnexin in both types of membrane domains, which might be a necessary requisite to aid the inherently unstable native conformation during their lifetime.
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11
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Harnessing the Physiological Functions of Cellular Prion Protein in the Kidneys: Applications for Treating Renal Diseases. Biomolecules 2021; 11:biom11060784. [PMID: 34067472 PMCID: PMC8224798 DOI: 10.3390/biom11060784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 12/16/2022] Open
Abstract
A cellular prion protein (PrPC) is a ubiquitous cell surface glycoprotein, and its physiological functions have been receiving increased attention. Endogenous PrPC is present in various kidney tissues and undergoes glomerular filtration. In prion diseases, abnormal prion proteins are found to accumulate in renal tissues and filtered into urine. Urinary prion protein could serve as a diagnostic biomarker. PrPC plays a role in cellular signaling pathways, reno-protective effects, and kidney iron uptake. PrPC signaling affects mitochondrial function via the ERK pathway and is affected by the regulatory influence of microRNAs, small molecules, and signaling proteins. Targeting PrPC in acute and chronic kidney disease could help improve iron homeostasis, ameliorate damage from ischemia/reperfusion injury, and enhance the efficacy of mesenchymal stem/stromal cell or extracellular vesicle-based therapeutic strategies. PrPC may also be under the influence of BMP/Smad signaling and affect the progression of TGF-β-related renal fibrosis. PrPC conveys TNF-α resistance in some renal cancers, and therefore, the coadministration of anti-PrPC antibodies improves chemotherapy. PrPC can be used to design antibody-drug conjugates, aptamer-drug conjugates, and customized tissue inhibitors of metalloproteinases to suppress cancer. With preclinical studies demonstrating promising results, further research on PrPC in the kidney may lead to innovative PrPC-based therapeutic strategies for renal disease.
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12
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Eskandari-Sedighi G, Cortez LM, Yang J, Daude N, Shmeit K, Sim V, Westaway D. Quaternary Structure Changes for PrP Sc Predate PrP C Downregulation and Neuronal Death During Progression of Experimental Scrapie Disease. Mol Neurobiol 2021; 58:375-390. [PMID: 32959170 PMCID: PMC7695655 DOI: 10.1007/s12035-020-02112-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 09/01/2020] [Indexed: 01/20/2023]
Abstract
Prion diseases are fatal neurodegenerative diseases in mammals with the unique characteristics of misfolding and aggregation of the cellular prion protein (PrPC) to the scrapie prion (PrPSc). Although neuroinflammation and neuronal loss feature within the disease process, the details of PrPC/PrPSc molecular transition to generate different aggregated species, and the correlation between each species and sequence of cellular events in disease pathogenesis are not fully understood. In this study, using mice inoculated with the RML isolate of mouse-adapted scrapie as a model, we applied asymmetric flow field-flow fractionation to monitor PrPC and PrPSc particle sizes and we also measured seeding activity and resistance to proteases. For cellular analysis in brain tissue, we measured inflammatory markers and synaptic damage, and used the isotropic fractionator to measure neuronal loss; these techniques were applied at different timepoints in a cross-sectional study of disease progression. Our analyses align with previous reports defining significant decreases in PrPC levels at pre-clinical stages of the disease and demonstrate that these decreases become significant before neuronal loss. We also identified the earliest PrPSc assemblies at a timepoint equivalent to 40% elapsed time for the disease incubation period; we propose that these assemblies, mostly composed of proteinase K (PK)-sensitive species, play an important role in triggering disease pathogenesis. Lastly, we show that the PK-resistant assemblies of PrPSc that appear at timepoints close to the terminal stage have similar biophysical characteristics, and hence that preparative use of PK-digestion selects for this specific subpopulation. In sum, our data argue that qualitative, as well as quantitative, changes in PrP conformers occur at the midpoint of subclinical phase; these changes affect quaternary structure and may occur at the threshold where adaptive responses become inadequate to deal with pathogenic processes.
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Affiliation(s)
- Ghazaleh Eskandari-Sedighi
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
| | - Leonardo M Cortez
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, AB, Canada
| | - Jing Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
| | - Nathalie Daude
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
| | - Klinton Shmeit
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
| | - Valerie Sim
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, AB, Canada
| | - David Westaway
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, AB, T6G 2M8, Canada.
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13
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Kang HE, Bian J, Kane SJ, Kim S, Selwyn V, Crowell J, Bartz JC, Telling GC. Incomplete glycosylation during prion infection unmasks a prion protein epitope that facilitates prion detection and strain discrimination. J Biol Chem 2020; 295:10420-10433. [PMID: 32513872 PMCID: PMC7383396 DOI: 10.1074/jbc.ra120.012796] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/31/2020] [Indexed: 11/06/2022] Open
Abstract
The causative factors underlying conformational conversion of cellular prion protein (PrPC) into its infectious counterpart (PrPSc) during prion infection remain undetermined, in part because of a lack of monoclonal antibodies (mAbs) that can distinguish these conformational isoforms. Here we show that the anti-PrP mAb PRC7 recognizes an epitope that is shielded from detection when glycans are attached to Asn-196. We observed that whereas PrPC is predisposed to full glycosylation and is therefore refractory to PRC7 detection, prion infection leads to diminished PrPSc glycosylation at Asn-196, resulting in an unshielded PRC7 epitope that is amenable to mAb recognition upon renaturation. Detection of PRC7-reactive PrPSc in experimental and natural infections with various mouse-adapted scrapie strains and with prions causing deer and elk chronic wasting disease and transmissible mink encephalopathy uncovered that incomplete PrPSc glycosylation is a consistent feature of prion pathogenesis. We also show that interrogating the conformational properties of the PRC7 epitope affords a direct means of distinguishing different prion strains. Because the specificity of our approach for prion detection and strain discrimination relies on the extent to which N-linked glycosylation shields or unshields PrP epitopes from antibody recognition, it dispenses with the requirement for additional standard manipulations to distinguish PrPSc from PrPC, including evaluation of protease resistance. Our findings not only highlight an innovative and facile strategy for prion detection and strain differentiation, but are also consistent with a mechanism of prion replication in which structural instability of incompletely glycosylated PrP contributes to the conformational conversion of PrPC to PrPSc.
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Affiliation(s)
- Hae-Eun Kang
- Prion Research Center (PRC), the Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Jifeng Bian
- Prion Research Center (PRC), the Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Sarah J. Kane
- Prion Research Center (PRC), the Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Sehun Kim
- Prion Research Center (PRC), the Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Vanessa Selwyn
- Prion Research Center (PRC), the Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado,Program in Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado
| | - Jenna Crowell
- Prion Research Center (PRC), the Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska
| | - Glenn C. Telling
- Prion Research Center (PRC), the Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado,Program in Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado,For correspondence: Glenn C. Telling,
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14
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Béringue V, Tixador P, Andréoletti O, Reine F, Castille J, Laï TL, Le Dur A, Laisné A, Herzog L, Passet B, Rezaei H, Vilotte JL, Laude H. Host prion protein expression levels impact prion tropism for the spleen. PLoS Pathog 2020; 16:e1008283. [PMID: 32702070 PMCID: PMC7402522 DOI: 10.1371/journal.ppat.1008283] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 08/04/2020] [Accepted: 06/22/2020] [Indexed: 11/18/2022] Open
Abstract
Prions are pathogens formed from abnormal conformers (PrPSc) of the host-encoded cellular prion protein (PrPC). PrPSc conformation to disease phenotype relationships extensively vary among prion strains. In particular, prions exhibit a strain-dependent tropism for lymphoid tissues. Prions can be composed of several substrain components. There is evidence that these substrains can propagate in distinct tissues (e.g. brain and spleen) of a single individual, providing an experimental paradigm to study the cause of prion tissue selectivity. Previously, we showed that PrPC expression levels feature in prion substrain selection in the brain. Transmission of sheep scrapie isolates (termed LAN) to multiple lines of transgenic mice expressing varying levels of ovine PrPC in their brains resulted in the phenotypic expression of the dominant sheep substrain in mice expressing near physiological PrPC levels, whereas a minor substrain replicated preferentially on high expresser mice. Considering that PrPC expression levels are markedly decreased in the spleen compared to the brain, we interrogate whether spleen PrPC dosage could drive prion selectivity. The outcome of the transmission of a large cohort of LAN isolates in the spleen from high expresser mice correlated with the replication rate dependency on PrPC amount. There was a prominent spleen colonization by the substrain preferentially replicating on low expresser mice and a relative incapacity of the substrain with higher-PrPC level need to propagate in the spleen. Early colonization of the spleen after intraperitoneal inoculation allowed neuropathological expression of the lymphoid substrain. In addition, a pair of substrain variants resulting from the adaptation of human prions to ovine high expresser mice, and exhibiting differing brain versus spleen tropism, showed different tropism on transmission to low expresser mice, with the lymphoid substrain colonizing the brain. Overall, these data suggest that PrPC expression levels are instrumental in prion lymphotropism. The cause of prion phenotype variation among prion strains remains poorly understood. In particular, prions replicate in a strain-dependent manner in the spleen. This can result in prion asymptomatic carriers. Based on our previous observations that dosage of the prion precursor (PrP) determined prion substrain selection in the brain, we examine whether PrP levels in the spleen could drive prion replication in this tissue, due to the low levels of the protein. We observe that the prion substrain with higher PrP need for replication does barely replicate in the spleen, while the component with low PrP need replicates efficiently. In addition, other human co-propagating prions with differing spleen and brain tropism showed different tropism on transmission to mice expressing low PrP levels, with the lymphoid substrain colonizing the brain. PrPC expression levels may thus be instrumental in prion tropism for the lymphoid tissue. From a diagnostic point of view, given the apparent complexity of prion diseases with respect to prion substrain composition, these data advocate to type extraneural tissues or fluids for a comprehensive identification of the circulating prions in susceptible mammals.
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Affiliation(s)
- Vincent Béringue
- Université Paris-Saclay, INRAE, UVSQ, VIM Jouy-en-Josas, France
- * E-mail:
| | | | | | - Fabienne Reine
- Université Paris-Saclay, INRAE, UVSQ, VIM Jouy-en-Josas, France
| | - Johan Castille
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, Jouy-en-Josas, France
| | - Thanh-Lan Laï
- Université Paris-Saclay, INRAE, UVSQ, VIM Jouy-en-Josas, France
| | - Annick Le Dur
- Université Paris-Saclay, INRAE, UVSQ, VIM Jouy-en-Josas, France
| | - Aude Laisné
- Université Paris-Saclay, INRAE, UVSQ, VIM Jouy-en-Josas, France
| | - Laetitia Herzog
- Université Paris-Saclay, INRAE, UVSQ, VIM Jouy-en-Josas, France
| | - Bruno Passet
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, Jouy-en-Josas, France
| | - Human Rezaei
- Université Paris-Saclay, INRAE, UVSQ, VIM Jouy-en-Josas, France
| | - Jean-Luc Vilotte
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, Jouy-en-Josas, France
| | - Hubert Laude
- Université Paris-Saclay, INRAE, UVSQ, VIM Jouy-en-Josas, France
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15
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Fu ZL, Mercier P, Eskandari-Sedighi G, Yang J, Westaway D, Sykes BD. Metabolomic study of disease progression in scrapie prion infected mice; validation of a novel method for brain metabolite extraction. Metabolomics 2020; 16:72. [PMID: 32533504 DOI: 10.1007/s11306-020-01690-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/28/2020] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Prion disease is a form of neurodegenerative disease caused by the misfolding and aggregation of cellular prion protein (PrPC). The neurotoxicity of the misfolded form of prion protein, PrPSc still remains understudied. Here we try to investigate this issue using a metabolomics approach. OBJECTIVES The intention was to identify and quantify the small-in-size and water-soluble metabolites extracted from mice brains infected with the Rocky Mountain Laboratory isolate of mouse-adapted scrapie prions (RML) and track changes in these metabolites during disease evolution. METHODS A total of 73 mice were inoculated with RML prions or normal brain homogenate control; brains were harvested at 30, 60, 90, 120 and 150 days post-inoculation (dpi). We devised a high-efficiency metabolite extraction method and used nuclear magnetic resonance spectroscopy to identify and quantify 50 metabolites in the brain extracts. Data were analyzed using multivariate approach. RESULTS Brain metabolome profiles of RML infected animals displayed continuous changes throughout the course of disease. Among the analyzed metabolites, the most noteworthy changes included increases in myo-inositol and glutamine as well as decreases in 4-aminobutyrate, acetate, aspartate and taurine. CONCLUSION We report a novel metabolite extraction method for lipid-rich tissue. As all the major metabolites are identifiable and quantifiable by magnetic resonance spectroscopy, this study suggests that tracking of neurochemical profiles could be effective in monitoring the progression of neurodegenerative diseases and useful for assessing the efficacy of candidate therapeutics.
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Affiliation(s)
- Ze-Lin Fu
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Pascal Mercier
- National High Field Nuclear Magnetic Resonance Centre (NANUC), Edmonton, AB, Canada
| | - Ghazaleh Eskandari-Sedighi
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Jing Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - David Westaway
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Brian D Sykes
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
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16
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Daude N, Kim C, Kang SG, Eskandari-Sedighi G, Haldiman T, Yang J, Fleck SC, Gomez-Cardona E, Han ZZ, Borrego-Ecija S, Wohlgemuth S, Julien O, Wille H, Molina-Porcel L, Gelpi E, Safar JG, Westaway D. Diverse, evolving conformer populations drive distinct phenotypes in frontotemporal lobar degeneration caused by the same MAPT-P301L mutation. Acta Neuropathol 2020; 139:1045-1070. [PMID: 32219515 PMCID: PMC7244472 DOI: 10.1007/s00401-020-02148-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/18/2020] [Accepted: 03/09/2020] [Indexed: 01/29/2023]
Abstract
Tau protein accumulation is a common denominator of major dementias, but this process is inhomogeneous, even when triggered by the same germline mutation. We considered stochastic misfolding of human tau conformers followed by templated conversion of native monomers as an underlying mechanism and derived sensitive conformational assays to test this concept. Assessments of brains from aged TgTauP301L transgenic mice revealed a prodromal state and three distinct signatures for misfolded tau. Frontotemporal lobar degeneration (FTLD)-MAPT-P301L patients with different clinical phenotypes also displayed three signatures, two resembling those found in TgTauP301L mice. As physicochemical and cell bioassays confirmed diverse tau strains in the mouse and human brain series, we conclude that evolution of diverse tau conformers is intrinsic to the pathogenesis of this uni-allelic form of tauopathy. In turn, effective therapeutic interventions in FTLD will need to address evolving repertoires of misfolded tau species rather than singular, static molecular targets.
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Affiliation(s)
- Nathalie Daude
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada
| | - Chae Kim
- Department of Pathology, Case Western Reserve University, Institute of Pathology Building, Rm 406, 2085 Adelbert Road, Cleveland, OH, 44106-4907, USA
| | - Sang-Gyun Kang
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada
| | - Ghazaleh Eskandari-Sedighi
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Tracy Haldiman
- Department of Pathology, Case Western Reserve University, Institute of Pathology Building, Rm 406, 2085 Adelbert Road, Cleveland, OH, 44106-4907, USA
| | - Jing Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada
| | - Shelaine C Fleck
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | | | - Zhuang Zhuang Han
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Sergi Borrego-Ecija
- Neurological Tissue Bank of the Biobanc, Hospital Clinic, IDIBAPS, Barcelona, Spain
| | - Serene Wohlgemuth
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada
| | - Olivier Julien
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Holger Wille
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | | | - Ellen Gelpi
- Neurological Tissue Bank of the Biobanc, Hospital Clinic, IDIBAPS, Barcelona, Spain
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Jiri G Safar
- Department of Pathology, Case Western Reserve University, Institute of Pathology Building, Rm 406, 2085 Adelbert Road, Cleveland, OH, 44106-4907, USA.
- Department of Neurology, Case Western Reserve University, Institute of Pathology Building, Rm 406, 2085 Adelbert Road, Cleveland, OH, 44106-4907, USA.
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, 204 Brain and Aging Research Building, Edmonton, T6G 2M8, Canada.
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
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17
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Duque Velásquez C, Kim C, Haldiman T, Kim C, Herbst A, Aiken J, Safar JG, McKenzie D. Chronic wasting disease (CWD) prion strains evolve via adaptive diversification of conformers in hosts expressing prion protein polymorphisms. J Biol Chem 2020; 295:4985-5001. [PMID: 32111742 PMCID: PMC7152757 DOI: 10.1074/jbc.ra120.012546] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/22/2020] [Indexed: 11/06/2022] Open
Abstract
Chronic wasting disease (CWD) is caused by an unknown spectrum of prions and has become enzootic in populations of cervid species that express cellular prion protein (PrPC) molecules varying in amino acid composition. These PrPC polymorphisms can affect prion transmission, disease progression, neuropathology, and emergence of new prion strains, but the mechanistic steps in prion evolution are not understood. Here, using conformation-dependent immunoassay, conformation stability assay, and protein-misfolding cyclic amplification, we monitored the conformational and phenotypic characteristics of CWD prions passaged through deer and transgenic mice expressing different cervid PrPC polymorphisms. We observed that transmission through hosts with distinct PrPC sequences diversifies the PrPCWD conformations and causes a shift toward oligomers with defined structural organization, replication rate, and host range. When passaged in host environments that restrict prion replication, distinct co-existing PrPCWD conformers underwent competitive selection, stabilizing a new prion strain. Nonadaptive conformers exhibited unstable replication and accumulated only to low levels. These results suggest a continuously evolving diversity of CWD conformers and imply a critical interplay between CWD prion plasticity and PrPC polymorphisms during prion strain evolution.
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Affiliation(s)
- Camilo Duque Velásquez
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
| | - Chae Kim
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Tracy Haldiman
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Chiye Kim
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
| | - Allen Herbst
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Judd Aiken
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Jiri G Safar
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
- Department of Neurology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Debbie McKenzie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
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18
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Lathe R, Darlix JL. Prion protein PrP nucleic acid binding and mobilization implicates retroelements as the replicative component of transmissible spongiform encephalopathy. Arch Virol 2020; 165:535-556. [PMID: 32025859 PMCID: PMC7024060 DOI: 10.1007/s00705-020-04529-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/13/2019] [Indexed: 12/21/2022]
Abstract
The existence of more than 30 strains of transmissible spongiform encephalopathy (TSE) and the paucity of infectivity of purified PrPSc, as well as considerations of PrP structure, are inconsistent with the protein-only (prion) theory of TSE. Nucleic acid is a strong contender as a second component. We juxtapose two key findings: (i) PrP is a nucleic-acid-binding antimicrobial protein that is similar to retroviral Gag proteins in its ability to trigger reverse transcription. (ii) Retroelement mobilization is widely seen in TSE disease. Given further evidence that PrP also mediates nucleic acid transport into and out of the cell, a strong case is to be made that a second element – retroelement nucleic acid – bound to PrP constitutes the second component necessary to explain the multiple strains of TSE.
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Affiliation(s)
- Richard Lathe
- Division of Infection Medicine, University of Edinburgh School of Medicine, Edinburgh, UK. .,Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, Moscow, Moscow Region, Russia.
| | - Jean-Luc Darlix
- Faculté de Pharmacie, Centre Nationale de la Recherche Scientifique (CNRS) Laboratory of Bioimaging and Pathologies (Unité Mixte de Recherche 7021), Université de Strasbourg, Illkirch, France.
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19
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Pradhan P, Srivastava A, Singh J, Biswas B, Saini A, Siddique I, Kumari P, Khan MA, Mishra A, Yadav PK, Kumar S, Bhavesh NS, Venkatraman P, Vivekanandan P, Kundu B. Prion protein transcription is auto-regulated through dynamic interactions with G-quadruplex motifs in its own promoter. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194479. [PMID: 31931179 DOI: 10.1016/j.bbagrm.2019.194479] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 12/26/2019] [Accepted: 12/28/2019] [Indexed: 11/19/2022]
Abstract
Cellular prion protein (PrP) misfolds into an aberrant and infectious scrapie form (PrPSc) that lead to fatal transmissible spongiform encephalopathies (TSEs). Association of prions with G-quadruplex (GQ) forming nucleic acid motifs has been reported, but implications of these interactions remain elusive. Herein, we show that the promoter region of the human prion gene (PRNP) contains two putative GQ motifs (Q1 and Q2) that assume stable, hybrid, intra-molecular quadruplex structures and bind with high affinity to PrP. Here, we investigate the ability of PrP to bind to the quadruplexes in its own promoter. We used a battery of techniques including SPR, NMR, CD, MD simulations and cell culture-based reporter assays. Our results show that PrP auto-regulates its expression by binding and resolving the GQs present in its own promoter. Furthermore, we map this resolvase-like activity to the N-terminal region (residues 23-89) of PrP. Our findings highlight a positive transcriptional-translational feedback regulation of the PRNP gene by PrP through dynamic unwinding of GQs in its promoter. Taken together, our results shed light on a yet unknown mechanism of regulation of the PRNP gene. This work provides the necessary framework for a plethora of studies on understanding the regulation of PrP levels and its implications in prion pathogenesis.
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Affiliation(s)
- Prashant Pradhan
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India
| | - Ankit Srivastava
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India
| | - Jasdeep Singh
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India
| | - Banhi Biswas
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India
| | - Akanksha Saini
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India
| | - Ibrar Siddique
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Pooja Kumari
- Transcription Regulation group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Mohd Asim Khan
- Department of Biochemistry, University of Delhi, South Campus, New Delhi 110021, India
| | - Akhilesh Mishra
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India
| | - Pramod Kumar Yadav
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India
| | - Shivani Kumar
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India
| | - Neel Sarovar Bhavesh
- Transcription Regulation group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Prasanna Venkatraman
- Tata Memorial Centre, Advanced Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai 410210, India; Homi Bhabha National Institute, 2nd floor, BARC Training School Complex, Anushaktinagar, Mumbai, Maharashtra 400094, India
| | - Perumal Vivekanandan
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India.
| | - Bishwajit Kundu
- Kusuma School of Biological Sciences, IIT Delhi, Hauz Khas, New Delhi 110016, India.
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20
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Minikel EV, Kuhn E, Cocco AR, Vallabh SM, Hartigan CR, Reidenbach AG, Safar JG, Raymond GJ, McCarthy MD, O'Keefe R, Llorens F, Zerr I, Capellari S, Parchi P, Schreiber SL, Carr SA. Domain-specific Quantification of Prion Protein in Cerebrospinal Fluid by Targeted Mass Spectrometry. Mol Cell Proteomics 2019; 18:2388-2400. [PMID: 31558565 PMCID: PMC6885701 DOI: 10.1074/mcp.ra119.001702] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/16/2019] [Indexed: 01/11/2023] Open
Abstract
Therapies currently in preclinical development for prion disease seek to lower prion protein (PrP) expression in the brain. Trials of such therapies are likely to rely on quantification of PrP in cerebrospinal fluid (CSF) as a pharmacodynamic biomarker and possibly as a trial endpoint. Studies using PrP ELISA kits have shown that CSF PrP is lowered in the symptomatic phase of disease, a potential confounder for reading out the effect of PrP-lowering drugs in symptomatic patients. Because misfolding or proteolytic cleavage could potentially render PrP invisible to ELISA even if its concentration were constant or increasing in disease, we sought to establish an orthogonal method for CSF PrP quantification. We developed a multi-species targeted mass spectrometry method based on multiple reaction monitoring (MRM) of nine PrP tryptic peptides quantified relative to an isotopically labeled recombinant protein standard for human samples, or isotopically labeled synthetic peptides for nonhuman species. Analytical validation experiments showed process replicate coefficients of variation below 15%, good dilution linearity and recovery, and suitable performance for both CSF and brain homogenate and across humans as well as preclinical species of interest. In n = 55 CSF samples from individuals referred to prion surveillance centers with rapidly progressive dementia, all six human PrP peptides, spanning the N- and C-terminal domains of PrP, were uniformly reduced in prion disease cases compared with individuals with nonprion diagnoses. Thus, lowered CSF PrP concentration in prion disease is a genuine result of the disease process and not an artifact of ELISA-based measurement. As a result, dose-finding studies for PrP lowering drugs may need to be conducted in presymptomatic at-risk individuals rather than in symptomatic patients. We provide a targeted mass spectrometry-based method suitable for preclinical quantification of CSF PrP as a tool for drug development.
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Affiliation(s)
- Eric Vallabh Minikel
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115; Prion Alliance, Cambridge, MA 02139; Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA 02142.
| | - Eric Kuhn
- Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA 02142; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115
| | - Alexandra R Cocco
- Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Sonia M Vallabh
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115; Prion Alliance, Cambridge, MA 02139
| | | | - Andrew G Reidenbach
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Jiri G Safar
- Departments of Pathology and Neurology Case Western Reserve University, Cleveland, OH 44106
| | - Gregory J Raymond
- Laboratory of Persistent Viral Diseases, NIAID Rocky Mountain Labs, Hamilton, MT 59840
| | - Michael D McCarthy
- Environmental Health and Safety, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Rhonda O'Keefe
- Environmental Health and Safety, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Franc Llorens
- National Reference Center for TSE, Georg-August University, Göttingen, 37073, Germany; Biomedical Research Networking Center on Neurodegenerative Diseases (CIBERNED), L'Hospitalet de Llobregat, 08908, Barcelona, Spain
| | - Inga Zerr
- National Reference Center for TSE, Georg-August University, Göttingen, 37073, Germany
| | - Sabina Capellari
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, 40139, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, 40123, Italy
| | - Piero Parchi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, 40139, Italy; Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, 40138, Italy
| | - Stuart L Schreiber
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142; Department of Chemistry & Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Steven A Carr
- Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA 02142.
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21
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Thüne K, Schmitz M, Villar-Piqué A, Altmeppen HC, Schlomm M, Zafar S, Glatzel M, Llorens F, Zerr I. The cellular prion protein and its derived fragments in human prion diseases and their role as potential biomarkers. Expert Rev Mol Diagn 2019; 19:1007-1018. [PMID: 31512940 DOI: 10.1080/14737159.2019.1667231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: Human prion diseases are a heterogeneous group of incurable and debilitating conditions characterized by a progressive degeneration of the central nervous system. The conformational changes of the cellular prion protein and its formation into an abnormal isoform, spongiform degeneration, neuronal loss, and neuroinflammation are central to prion disease pathogenesis. It has been postulated that truncated variants of aggregation-prone proteins are implicated in neurodegenerative mechanisms. An increasing body of evidence indicates that proteolytic fragments and truncated variants of the prion protein are formed and accumulated in the brain of prion disease patients. These prion protein variants provide a high degree of relevance to disease pathology and diagnosis. Areas covered: In the present review, we summarize the current knowledge on the occurrence of truncated prion protein species and their potential roles in pathophysiological states during prion diseases progression. In addition, we discuss their usability as a diagnostic biomarker in prion diseases. Expert opinion: Either as a primary factor in the formation of prion diseases or as a consequence from neuropathological affection, abnormal prion protein variants and fragments may provide independent information about mechanisms of prion conversion, pathological states, or disease progression.
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Affiliation(s)
- Katrin Thüne
- Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen , Göttingen , Germany
| | - Matthias Schmitz
- Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen , Göttingen , Germany
| | - Anna Villar-Piqué
- Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen , Göttingen , Germany.,Network Center for Biomedical Research in Neurodegenerative Diseases, Institute Carlos III, Ministry of Health, CIBERNED, Hospitalet de Llobregat , Spain
| | | | - Markus Schlomm
- Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen , Göttingen , Germany
| | - Saima Zafar
- Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen , Göttingen , Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center HH-Eppendorf (UKE) , Hamburg , Germany
| | - Franc Llorens
- Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen , Göttingen , Germany.,Network Center for Biomedical Research in Neurodegenerative Diseases, Institute Carlos III, Ministry of Health, CIBERNED, Hospitalet de Llobregat , Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat , Barcelona , Spain
| | - Inga Zerr
- Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen , Göttingen , Germany
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22
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Nonno R, Notari S, Di Bari MA, Cali I, Pirisinu L, d'Agostino C, Cracco L, Kofskey D, Vanni I, Lavrich J, Parchi P, Agrimi U, Gambetti P. Variable Protease-Sensitive Prionopathy Transmission to Bank Voles. Emerg Infect Dis 2019; 25:73-81. [PMID: 30561322 PMCID: PMC6302590 DOI: 10.3201/eid2501.180807] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Variably protease-sensitive prionopathy (VPSPr), a recently described human sporadic prion disease, features a protease-resistant, disease-related prion protein (resPrPD) displaying 5 fragments reminiscent of Gerstmann-Sträussler-Scheinker disease. Experimental VPSPr transmission to human PrP-expressing transgenic mice, although replication of the VPSPr resPrPD profile succeeded, has been incomplete because of second passage failure. We bioassayed VPSPr in bank voles, which are susceptible to human prion strains. Transmission was complete; first-passage attack rates were 5%-35%, and second-passage rates reached 100% and survival times were 50% shorter. We observed 3 distinct phenotypes and resPrPD profiles; 2 imitated sporadic Creutzfeldt-Jakob disease resPrPD, and 1 resembled Gerstmann-Sträussler-Scheinker disease resPrPD. The first 2 phenotypes may be related to the presence of minor PrPD components in VPSPr. Full VPSPr transmission confirms permissiveness of bank voles to human prions and suggests that bank vole PrP may efficiently reveal an underrepresented native strain but does not replicate the complex VPSPr PrPD profile.
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23
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Proteasomal Inhibition Redirects the PrP-Like Shadoo Protein to the Nucleus. Mol Neurobiol 2019; 56:7888-7904. [PMID: 31129810 PMCID: PMC6815274 DOI: 10.1007/s12035-019-1623-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/24/2019] [Indexed: 01/08/2023]
Abstract
The Shadoo protein (Sho) exhibits homology to the hydrophobic region of the cellular isoform of prion protein (PrPC). As prion-infected brains gradually accumulate infectivity-associated isoforms of prion protein (PrPSc), levels of mature endogenous Sho become reduced. To study the regulatory effect of the proteostatic network on Sho expression, we investigated the action of lactacystin, MG132, NH4Cl, and 3-methyladenine (3-MA) in two cell culture models. In primary mixed neuronal and glial cell cultures (MNGCs) from transgenic mice expressing wild-type Sho from the PrP gene promoter (Tg.Sprn mice), lactacystin- and MG132-mediated inhibition of proteasomal activity shifted the repertoire of Sho species towards unglycosylated forms appearing in the nuclei; conversely, the autophagic modulators NH4Cl and 3-MA did not affect Sho or PrPC glycosylation patterns. Mouse N2a neuroblastoma cells expressing Sho under control of a housekeeping gene promoter treated with MG132 or lactacystin also showed increased nuclear localization of unglycosylated Sho. As two proteasomal inhibitors tested in two cell paradigms caused redirection of Sho to nuclei at the expense of processing through the secretory pathway, our findings define a balanced shift in subcellular localization that thereby differs from the decreases in net Sho species seen in prion-infected brains. Our data are indicative of a physiological pathway to access Sho functions in the nucleus under conditions of impaired proteasomal activity. We also infer that these conditions would comprise a context wherein Sho’s N-terminal nucleic acid–binding RGG repeat region is brought into play.
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24
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Heterogeneity and Architecture of Pathological Prion Protein Assemblies: Time to Revisit the Molecular Basis of the Prion Replication Process? Viruses 2019; 11:v11050429. [PMID: 31083283 PMCID: PMC6563208 DOI: 10.3390/v11050429] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 01/24/2023] Open
Abstract
Prions are proteinaceous infectious agents responsible for a range of neurodegenerative diseases in animals and humans. Prion particles are assemblies formed from a misfolded, β-sheet rich, aggregation-prone isoform (PrPSc) of the host-encoded cellular prion protein (PrPC). Prions replicate by recruiting and converting PrPC into PrPSc, by an autocatalytic process. PrPSc is a pleiomorphic protein as different conformations can dictate different disease phenotypes in the same host species. This is the basis of the strain phenomenon in prion diseases. Recent experimental evidence suggests further structural heterogeneity in PrPSc assemblies within specific prion populations and strains. Still, this diversity is rather seen as a size continuum of assemblies with the same core structure, while analysis of the available experimental data points to the existence of structurally distinct arrangements. The atomic structure of PrPSc has not been elucidated so far, making the prion replication process difficult to understand. All currently available models suggest that PrPSc assemblies exhibit a PrPSc subunit as core constituent, which was recently identified. This review summarizes our current knowledge on prion assembly heterogeneity down to the subunit level and will discuss its importance with regard to the current molecular principles of the prion replication process.
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25
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Prion protein quantification in human cerebrospinal fluid as a tool for prion disease drug development. Proc Natl Acad Sci U S A 2019; 116:7793-7798. [PMID: 30936307 DOI: 10.1073/pnas.1901947116] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Reduction of native prion protein (PrP) levels in the brain is an attractive strategy for the treatment or prevention of human prion disease. Clinical development of any PrP-reducing therapeutic will require an appropriate pharmacodynamic biomarker: a practical and robust method for quantifying PrP, and reliably demonstrating its reduction in the central nervous system (CNS) of a living patient. Here we evaluate the potential of ELISA-based quantification of human PrP in human cerebrospinal fluid (CSF) to serve as a biomarker for PrP-reducing therapeutics. We show that CSF PrP is highly sensitive to plastic adsorption during handling and storage, but its loss can be minimized by the addition of detergent. We find that blood contamination does not affect CSF PrP levels, and that CSF PrP and hemoglobin are uncorrelated, together suggesting that CSF PrP is CNS derived, supporting its relevance for monitoring the tissue of interest and in keeping with high PrP abundance in brain relative to blood. In a cohort with controlled sample handling, CSF PrP exhibits good within-subject test-retest reliability (mean coefficient of variation, 13% in samples collected 8-11 wk apart), a sufficiently stable baseline to allow therapeutically meaningful reductions in brain PrP to be readily detected in CSF. Together, these findings supply a method for monitoring the effect of a PrP-reducing drug in the CNS, and will facilitate development of prion disease therapeutics with this mechanism of action.
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26
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Salvesen Ø, Tatzelt J, Tranulis MA. The prion protein in neuroimmune crosstalk. Neurochem Int 2018; 130:104335. [PMID: 30448564 DOI: 10.1016/j.neuint.2018.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/04/2018] [Accepted: 11/14/2018] [Indexed: 01/11/2023]
Abstract
The cellular prion protein (PrPC) is a medium-sized glycoprotein, attached to the cell surface by a glycosylphosphatidylinositol anchor. PrPC is encoded by a single-copy gene, PRNP, which is abundantly expressed in the central nervous system and at lower levels in non-neuronal cells, including those of the immune system. Evidence from experimental knockout of PRNP in rodents, goats, and cattle and the occurrence of a nonsense mutation in goat that prevents synthesis of PrPC, have shown that the molecule is non-essential for life. Indeed, no easily recognizable phenotypes are associate with a lack of PrPC, except the potentially advantageous trait that animals without PrPC cannot develop prion disease. This is because, in prion diseases, PrPC converts to a pathogenic "scrapie" conformer, PrPSc, which aggregates and eventually induces neurodegeneration. In addition, endogenous neuronal PrPC serves as a toxic receptor to mediate prion-induced neurotoxicity. Thus, PrPC is an interesting target for treatment of prion diseases. Although loss of PrPC has no discernable effect, alteration of its normal physiological function can have very harmful consequences. It is therefore important to understand cellular processes involving PrPC, and research of this topic has advanced considerably in the past decade. Here, we summarize data that indicate the role of PrPC in modulating immune signaling, with emphasis on neuroimmune crosstalk both under basal conditions and during inflammatory stress.
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Affiliation(s)
- Øyvind Salvesen
- Faculty of Veterinary Medicine, Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Sandnes, Norway.
| | - Jörg Tatzelt
- Department Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Germany.
| | - Michael A Tranulis
- Faculty of Veterinary Medicine, Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway.
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27
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Sohrab SS, Suhail M, Ali A, Kamal MA, Husen A, Ahmad F, Azhar EI, Greig NH. Role of viruses, prions and miRNA in neurodegenerative disorders and dementia. Virusdisease 2018; 29:419-433. [PMID: 30539044 DOI: 10.1007/s13337-018-0492-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 09/14/2018] [Indexed: 12/13/2022] Open
Abstract
Dementia is known as loss of cellular communications in the brain at a region caused by multi-factorial diseases and pathogenic infections. Approximately eighty percent reported cases of Alzheimer's disease are followed by vascular dementia. The common symptoms of dementia include memory loss, concentration problems, thinking, and language solving situations. Dementia is a multifactorial disease but based on latest research; various reports have been published describing the linkage and role of viruses, prions and miRNAs in neurodegeneration and neurodegenerative disorders resulting into dementia and due to this we selected to review and provide latest information related to dementia. MiRNAs are small non-coding RNAs carrying genetic regulatory information contributing to neurological disorders among human and animals. A prion is an infectious agent made of protein material. Recently, it has been reported that prions play a significant role in signaling processes, resulting in amyloidogenesis and neurological disorders. Viruses attack human immune system and central nervous system and affect classical pathways of neurodegenerative diseases. Comprehensive understandings of the expression profiles and activities of these miRNAs, Prions, Viruses will illuminate their roles as potential therapeutic targets in neurodegeneration and may lead to the discovery of breakthrough treatment strategies for neurodegenerative disorders and dementia. The provided information will further be significant not only in neuro-scientific research, but also in designing and development of management strategies for dementia.
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Affiliation(s)
- Sayed Sartaj Sohrab
- 1Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Post Box No-80216, Jeddah, 21589 Saudi Arabia
| | - Mohd Suhail
- 2King Fahd Medical Research Center, King Abdulaziz University, P.O. Box No 21589, Jeddah, Saudi Arabia
| | - Ashraf Ali
- 2King Fahd Medical Research Center, King Abdulaziz University, P.O. Box No 21589, Jeddah, Saudi Arabia
| | - Mohammad Amjad Kamal
- 2King Fahd Medical Research Center, King Abdulaziz University, P.O. Box No 21589, Jeddah, Saudi Arabia.,Enzymoics, 7 Peterlee Place, Hebersham, NSW 2770 Australia.,Novel Global Community Educational Foundation, Sydney, Australia
| | - Azamal Husen
- 6Department of Biology, College of Natural and Computational Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia
| | - Fahim Ahmad
- 7Drug Discovery Division, Southern Research Institute, 2000, Ninth Ave, South, Birmingham, AL 35205 USA
| | - Esam Ibraheem Azhar
- 1Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Post Box No-80216, Jeddah, 21589 Saudi Arabia.,5Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Nigel H Greig
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National, Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore, MD 21224 USA
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28
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Prion acute synaptotoxicity is largely driven by protease-resistant PrPSc species. PLoS Pathog 2018; 14:e1007214. [PMID: 30089152 PMCID: PMC6101418 DOI: 10.1371/journal.ppat.1007214] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 08/20/2018] [Accepted: 07/12/2018] [Indexed: 01/09/2023] Open
Abstract
Although misfolding of normal prion protein (PrPC) into abnormal conformers (PrPSc) is critical for prion disease pathogenesis our current understanding of the underlying molecular pathophysiology is rudimentary. Exploiting an electrophysiology paradigm, herein we report that at least modestly proteinase K (PK)-resistant PrPSc (PrPres) species are acutely synaptotoxic. Brief exposure to ex vivo PrPSc from two mouse-adapted prion strains (M1000 and MU02) prepared as crude brain homogenates (cM1000 and cMU02) and cell lysates from chronically M1000-infected RK13 cells (MoRK13-Inf) caused significant impairment of hippocampal CA1 region long-term potentiation (LTP), with the LTP disruption approximating that reported during the evolution of murine prion disease. Proof of PrPSc (especially PrPres) species as the synaptotoxic agent was demonstrated by: significant rescue of LTP following selective immuno-depletion of total PrP from cM1000 (dM1000); modestly PK-treated cM1000 (PK+M1000) retaining full synaptotoxicity; and restoration of the LTP impairment when employing reconstituted, PK-eluted, immuno-precipitated M1000 preparations (PK+IP-M1000). Additional detailed electrophysiological analyses exemplified by impairment of post-tetanic potentiation (PTP) suggest possible heightened pre-synaptic vulnerability to the acute synaptotoxicity. This dysfunction correlated with cumulative insufficiency of replenishment of the readily releasable pool (RRP) of vesicles during repeated high-frequency stimulation utilised for induction of LTP. Broadly comparable results with LTP and PTP impairment were obtained utilizing hippocampal slices from PrPC knockout (PrPo/o) mice, with cM1000 serial dilution assessments revealing similar sensitivity of PrPo/o and wild type (WT) slices. Size fractionation chromatography demonstrated that synaptotoxic PrP correlated with PK-resistant species >100kDa, consistent with multimeric PrPSc, with levels of these species >6 ng/ml appearing sufficient to induce synaptic dysfunction. Biochemical analyses of hippocampal slices manifesting acute synaptotoxicity demonstrated reduced levels of multiple key synaptic proteins, albeit with noteworthy differences in PrPo/o slices, while such changes were absent in hippocampi demonstrating rescued LTP through treatment with dM1000. Our findings offer important new mechanistic insights into the synaptic impairment underlying prion disease, enhancing prospects for development of targeted effective therapies. Misfolding of the normal prion protein (PrPC) into disease-associated conformations (PrPSc) is the critical initiating step for prion diseases. Similar to other neurodegenerative disorders, progressive failure of brain synapses is considered a primary deleterious event underpinning prion disease evolution. Our current understanding of the underlying mechanisms associated with synaptic failure is rudimentary contributing to difficulties in developing effective treatments. Herein we report the use of an electrophysiology paradigm that allowed us to demonstrate that at least modestly proteinase K (PK)-resistant PrPSc species from two mouse-adapted prion strains (M1000 and MU02) are directly synaptotoxic causing significant acute impairment of hippocampal CA1 region long-term potentiation (LTP). Of note, the LTP disruption approximated that reported in prion animal models. Additional detailed analyses provided novel pathophysiological insights suggesting possible heightened pre-synaptic vulnerability to the acute synaptotoxicity through impairment of replenishment of the readily releasable pool of neurotransmitter vesicles, while biochemical analyses demonstrated reduced levels of multiple key pre-and post-synaptic proteins. Broadly similar acute synaptic dysfunction and dose-response susceptibility were observed in slices from mice not expressing PrPC albeit with minor but noteworthy differences in electrophysiological and biochemical findings. Our study offers important new mechanistic insights into the synaptic impairment underlying prion disease, enhancing prospects for development effective therapies.
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29
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The function of the cellular prion protein in health and disease. Acta Neuropathol 2018; 135:159-178. [PMID: 29151170 DOI: 10.1007/s00401-017-1790-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 12/11/2022]
Abstract
The essential role of the cellular prion protein (PrPC) in prion disorders such as Creutzfeldt-Jakob disease is well documented. Moreover, evidence is accumulating that PrPC may act as a receptor for protein aggregates and transduce neurotoxic signals in more common neurodegenerative disorders, such as Alzheimer's disease. Although the pathological roles of PrPC have been thoroughly characterized, a general consensus on its physiological function within the brain has not yet been established. Knockout studies in various organisms, ranging from zebrafish to mice, have implicated PrPC in a diverse range of nervous system-related activities that include a key role in the maintenance of peripheral nerve myelination as well as a general ability to protect against neurotoxic stimuli. Thus, the function of PrPC may be multifaceted, with different cell types taking advantage of unique aspects of its biology. Deciphering the cellular function(s) of PrPC and the consequences of its absence is not simply an academic curiosity, since lowering PrPC levels in the brain is predicted to be a powerful therapeutic strategy for the treatment of prion disease. In this review, we outline the various approaches that have been employed in an effort to uncover the physiological and pathological functions of PrPC. While these studies have revealed important clues about the biology of the prion protein, the precise reason for PrPC's existence remains enigmatic.
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30
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Leighton PLA, Allison WT. Protein Misfolding in Prion and Prion-Like Diseases: Reconsidering a Required Role for Protein Loss-of-Function. J Alzheimers Dis 2018; 54:3-29. [PMID: 27392869 DOI: 10.3233/jad-160361] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Prion disease research has contributed much toward understanding other neurodegenerative diseases, including recent demonstrations that Alzheimer's disease (AD) and other neurodegenerative diseases are prion-like. Prion-like diseases involve the spread of degeneration between individuals and/or among cells or tissues via template directed misfolding, wherein misfolded protein conformers propagate disease by causing normal proteins to misfold. Here we use the premise that AD, amyotrophic lateral sclerosis, Huntington's disease, and other similar diseases are prion-like and ask: Can we apply knowledge gained from studies of these prion-like diseases to resolve debates about classical prion diseases? We focus on controversies about what role(s) protein loss-of-function might have in prion diseases because this has therapeutic implications, including for AD. We examine which loss-of-function events are recognizable in prion-like diseases by considering the normal functions of the proteins before their misfolding and aggregation. We then delineate scenarios wherein gain-of-function and/or loss-of-function would be necessary or sufficient for neurodegeneration. We consider roles of PrPC loss-of-function in prion diseases and in AD, and conclude that the conventional wisdom that prion diseases are 'toxic gain-of-function diseases' has limitations. While prion diseases certainly have required gain-of-function components, we propose that disease phenotypes are predominantly caused by deficits in the normal physiology of PrPC and its interaction partners as PrPC converts to PrPSc. In this model, gain-of-function serves mainly to spread disease, and loss-of-function directly mediates neuron dysfunction. We propose experiments and predictions to assess our conclusion. Further study on the normal physiological roles of these key proteins is warranted.
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Affiliation(s)
- Patricia L A Leighton
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB, Canada.,Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - W Ted Allison
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB, Canada.,Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
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31
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Igel-Egalon A, Béringue V, Rezaei H, Sibille P. Prion Strains and Transmission Barrier Phenomena. Pathogens 2018; 7:E5. [PMID: 29301257 PMCID: PMC5874731 DOI: 10.3390/pathogens7010005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/25/2017] [Accepted: 12/26/2017] [Indexed: 11/30/2022] Open
Abstract
Several experimental evidences show that prions are non-conventional pathogens, which physical support consists only in proteins. This finding raised questions regarding the observed prion strain-to-strain variations and the species barrier that happened to be crossed with dramatic consequences on human health and veterinary policies during the last 3 decades. This review presents a focus on a few advances in the field of prion structure and prion strains characterization: from the historical approaches that allowed the concept of prion strains to emerge, to the last results demonstrating that a prion strain may in fact be a combination of a few quasi species with subtle biophysical specificities. Then, we will focus on the current knowledge on the factors that impact species barrier strength and species barrier crossing. Finally, we present probable scenarios on how the interaction of strain properties with host characteristics may account for differential selection of new conformer variants and eventually species barrier crossing.
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Affiliation(s)
- Angélique Igel-Egalon
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, UR892, 78350 Jouy-en-Josas, France.
| | - Vincent Béringue
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, UR892, 78350 Jouy-en-Josas, France.
| | - Human Rezaei
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, UR892, 78350 Jouy-en-Josas, France.
| | - Pierre Sibille
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, UR892, 78350 Jouy-en-Josas, France.
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32
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Abstract
Scrapie was the first prion disease to be recognised and the study of this disease in sheep and goats has provided a wealth of information not only for scrapie but also for the other prion diseases. All prion diseases are under strong genetic control of the prion gene PRNP, independent of whether they are typical or atypical scrapie and which of the different prion strains is causing infection. Decades of studies using experimental disease challenges and field surveys have established disease association models, in which species-specific amino acid variations in the prion or PrP protein, encoded by the PRNP gene, can predict disease susceptibility or resistance. PRNP genetics represents an important and successful basis for implementing scrapie eradication strategies in sheep and goats. In general terms these studies have revealed that there appear to be many more amino acid changes in PrP leading to increased resistance than to higher susceptibility. Most changes are in the globular part of PrP protein and three regions appear to have major influence. This knowledge can be transferred into prion diseases of other species to facilitate genetic control strategies. However, an obstacle remains with the lack of fully understanding the underlying molecular mechanism, impeding our ability to deal with the difference in the genetic control between typical and atypical forms of scrapie or to predict association in newly infected species. This chapter will discuss the advances in both typical and atypical scrapie from a genetic perspective.
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Affiliation(s)
- Wilfred Goldmann
- Neurobiology Division, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, United Kingdom.
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33
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What Is Our Current Understanding of PrP Sc-Associated Neurotoxicity and Its Molecular Underpinnings? Pathogens 2017; 6:pathogens6040063. [PMID: 29194372 PMCID: PMC5750587 DOI: 10.3390/pathogens6040063] [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] [Received: 09/29/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 01/15/2023] Open
Abstract
The prion diseases are a collection of fatal, transmissible neurodegenerative diseases that cause rapid onset dementia and ultimately death. Uniquely, the infectious agent is a misfolded form of the endogenous cellular prion protein, termed PrPSc. Despite the identity of the molecular agent remaining the same, PrPSc can cause a range of diseases with hereditary, spontaneous or iatrogenic aetiologies. However, the link between PrPSc and toxicity is complex, with subclinical cases of prion disease discovered, and prion neurodegeneration without obvious PrPSc deposition. The toxic mechanisms by which PrPSc causes the extensive neuropathology are still poorly understood, although recent advances are beginning to unravel the molecular underpinnings, including oxidative stress, disruption of proteostasis and induction of the unfolded protein response. This review will discuss the diseases caused by PrPSc toxicity, the nature of the toxicity of PrPSc, and our current understanding of the downstream toxic signaling events triggered by the presence of PrPSc.
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Roguski A, Gill AC. The Role of the Mammalian Prion Protein in the Control of Sleep. Pathogens 2017; 6:pathogens6040058. [PMID: 29149024 PMCID: PMC5750582 DOI: 10.3390/pathogens6040058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/08/2017] [Accepted: 11/13/2017] [Indexed: 01/09/2023] Open
Abstract
Sleep disruption is a prevalent clinical feature in many neurodegenerative disorders, including human prion diseases where it can be the defining dysfunction, as in the case of the "eponymous" fatal familial insomnia, or an early-stage symptom as in certain types of Creutzfeldt-Jakob disease. It is important to establish the role of the cellular prion protein (PrPC), the key molecule involved in prion pathogenesis, within the sleep-wake system in order to understand fully the mechanisms underlying its contribution to both healthy circadian rhythmicity and sleep dysfunction during disease. Although severe disruption to the circadian rhythm and melatonin release is evident during the pathogenic phases of some prion diseases, untangling whether PrPC plays a role in circadian rhythmicity, as suggested in mice deficient for PrPC expression, is challenging given the lack of basic experimental research. We provide a short review of the small amount of direct literature focused on the role of PrPC in melatonin and circadian rhythm regulation, as well as suggesting mechanisms by which PrPC might exert influence upon noradrenergic and dopaminergic signaling and melatonin synthesis. Future research in this area should focus upon isolating the points of dysfunction within the retino-pineal pathway and further investigate PrPC mediation of pinealocyte GPCR activity.
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Affiliation(s)
- Amber Roguski
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush Veterinary Centre, Edinburgh EH25 9RG, UK.
| | - Andrew C Gill
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush Veterinary Centre, Edinburgh EH25 9RG, UK.
- School of Chemistry, Joseph Banks Laboratories, University of Lincoln, Green Lane, Lincoln, Lincolnshire LN6 7DL, UK.
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Allison WT, DuVal MG, Nguyen-Phuoc K, Leighton PLA. Reduced Abundance and Subverted Functions of Proteins in Prion-Like Diseases: Gained Functions Fascinate but Lost Functions Affect Aetiology. Int J Mol Sci 2017; 18:E2223. [PMID: 29064456 PMCID: PMC5666902 DOI: 10.3390/ijms18102223] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/18/2017] [Accepted: 10/20/2017] [Indexed: 12/12/2022] Open
Abstract
Prions have served as pathfinders that reveal many aspects of proteostasis in neurons. The recent realization that several prominent neurodegenerative diseases spread via a prion-like mechanism illuminates new possibilities for diagnostics and therapeutics. Thus, key proteins in Alzheimer Disease and Amyotrophic lateral sclerosis (ALS), including amyloid-β precursor protein, Tau and superoxide dismutase 1 (SOD1), spread to adjacent cells in their misfolded aggregated forms and exhibit template-directed misfolding to induce further misfolding, disruptions to proteostasis and toxicity. Here we invert this comparison to ask what these prion-like diseases can teach us about the broad prion disease class, especially regarding the loss of these key proteins' function(s) as they misfold and aggregate. We also consider whether functional amyloids might reveal a role for subverted protein function in neurodegenerative disease. Our synthesis identifies SOD1 as an exemplar of protein functions being lost during prion-like protein misfolding, because SOD1 is inherently unstable and loses function in its misfolded disease-associated form. This has under-appreciated parallels amongst the canonical prion diseases, wherein the normally folded prion protein, PrPC, is reduced in abundance in fatal familial insomnia patients and during the preclinical phase in animal models, apparently via proteostatic mechanisms. Thus while template-directed misfolding and infectious properties represent gain-of-function that fascinates proteostasis researchers and defines (is required for) the prion(-like) diseases, loss and subversion of the functions attributed to hallmark proteins in neurodegenerative disease needs to be integrated into design towards effective therapeutics. We propose experiments to uniquely test these ideas.
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Affiliation(s)
- W Ted Allison
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2M8, Canada.
| | - Michèle G DuVal
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
| | - Kim Nguyen-Phuoc
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2M8, Canada.
| | - Patricia L A Leighton
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
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Linsenmeier L, Altmeppen HC, Wetzel S, Mohammadi B, Saftig P, Glatzel M. Diverse functions of the prion protein - Does proteolytic processing hold the key? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2128-2137. [PMID: 28693923 DOI: 10.1016/j.bbamcr.2017.06.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/27/2017] [Accepted: 06/29/2017] [Indexed: 02/07/2023]
Abstract
Proteolytic processing of the cellular and disease-associated form of the prion protein leads to generation of bioactive soluble prion protein fragments and modifies the structure and function of its cell-bound form. The nature of proteases responsible for shedding, α-, β-, and γ-cleavage of the prion protein are only partially identified and their regulation is largely unknown. Here, we provide an overview of the increasingly multifaceted picture of prion protein proteolysis and shed light on physiological and pathological roles associated with these cleavages. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.
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Affiliation(s)
- Luise Linsenmeier
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hermann C Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sebastian Wetzel
- Institute of Biochemistry, Christian Albrechts University Kiel, Kiel, Germany
| | - Behnam Mohammadi
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Paul Saftig
- Institute of Biochemistry, Christian Albrechts University Kiel, Kiel, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Voisset C, Blondel M, Jones GW, Friocourt G, Stahl G, Chédin S, Béringue V, Gillet R. The double life of the ribosome: When its protein folding activity supports prion propagation. Prion 2017; 11:89-97. [PMID: 28362551 DOI: 10.1080/19336896.2017.1303587] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
It is no longer necessary to demonstrate that ribosome is the central machinery of protein synthesis. But it is less known that it is also key player of the protein folding process through another conserved function: the protein folding activity of the ribosome (PFAR). This ribozyme activity, discovered more than 2 decades ago, depends upon the domain V of the large rRNA within the large subunit of the ribosome. Surprisingly, we discovered that anti-prion compounds are also potent PFAR inhibitors, highlighting an unexpected link between PFAR and prion propagation. In this review, we discuss the ancestral origin of PFAR in the light of the ancient RNA world hypothesis. We also consider how this ribosomal activity fits into the landscape of cellular protein chaperones involved in the appearance and propagation of prions and other amyloids in mammals. Finally, we examine how drugs targeting the protein folding activity of the ribosome could be active against mammalian prion and other protein aggregation-based diseases, making PFAR a promising therapeutic target for various human protein misfolding diseases.
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Affiliation(s)
- Cécile Voisset
- a Inserm UMR 1078 , Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire , Brest , France
| | - Marc Blondel
- a Inserm UMR 1078 , Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire , Brest , France
| | - Gary W Jones
- b School of Clinical and Applied Sciences , Faculty of Health and Social Sciences, Leeds Beckett University , Leeds , UK
| | - Gaëlle Friocourt
- a Inserm UMR 1078 , Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire , Brest , France
| | - Guillaume Stahl
- c Laboratoire de Biologie Moléculaire Eucaryotes , CNRS, Université de Toulouse , Toulouse , France
| | - Stéphane Chédin
- d Institute for Integrative Biology of the Cell (I2BC), UMR 9198, CEA, CNRS, Université Paris-Sud, CEA/Saclay, SBIGeM , Gif-sur-Yvette , France
| | | | - Reynald Gillet
- f Université de Rennes 1, CNRS UMR 6290 IGDR , Rennes , France
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Castle AR, Gill AC. Physiological Functions of the Cellular Prion Protein. Front Mol Biosci 2017; 4:19. [PMID: 28428956 PMCID: PMC5382174 DOI: 10.3389/fmolb.2017.00019] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/22/2017] [Indexed: 01/09/2023] Open
Abstract
The prion protein, PrPC, is a small, cell-surface glycoprotein notable primarily for its critical role in pathogenesis of the neurodegenerative disorders known as prion diseases. A hallmark of prion diseases is the conversion of PrPC into an abnormally folded isoform, which provides a template for further pathogenic conversion of PrPC, allowing disease to spread from cell to cell and, in some circumstances, to transfer to a new host. In addition to the putative neurotoxicity caused by the misfolded form(s), loss of normal PrPC function could be an integral part of the neurodegenerative processes and, consequently, significant research efforts have been directed toward determining the physiological functions of PrPC. In this review, we first summarise important aspects of the biochemistry of PrPC before moving on to address the current understanding of the various proposed functions of the protein, including details of the underlying molecular mechanisms potentially involved in these functions. Over years of study, PrPC has been associated with a wide array of different cellular processes and many interacting partners have been suggested. However, recent studies have cast doubt on the previously well-established links between PrPC and processes such as stress-protection, copper homeostasis and neuronal excitability. Instead, the functions best-supported by the current literature include regulation of myelin maintenance and of processes linked to cellular differentiation, including proliferation, adhesion, and control of cell morphology. Intriguing connections have also been made between PrPC and the modulation of circadian rhythm, glucose homeostasis, immune function and cellular iron uptake, all of which warrant further investigation.
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Linden R. The Biological Function of the Prion Protein: A Cell Surface Scaffold of Signaling Modules. Front Mol Neurosci 2017; 10:77. [PMID: 28373833 PMCID: PMC5357658 DOI: 10.3389/fnmol.2017.00077] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 03/06/2017] [Indexed: 12/18/2022] Open
Abstract
The prion glycoprotein (PrPC) is mostly located at the cell surface, tethered to the plasma membrane through a glycosyl-phosphatydil inositol (GPI) anchor. Misfolding of PrPC is associated with the transmissible spongiform encephalopathies (TSEs), whereas its normal conformer serves as a receptor for oligomers of the β-amyloid peptide, which play a major role in the pathogenesis of Alzheimer’s Disease (AD). PrPC is highly expressed in both the nervous and immune systems, as well as in other organs, but its functions are controversial. Extensive experimental work disclosed multiple physiological roles of PrPC at the molecular, cellular and systemic levels, affecting the homeostasis of copper, neuroprotection, stem cell renewal and memory mechanisms, among others. Often each such process has been heralded as the bona fide function of PrPC, despite restricted attention paid to a selected phenotypic trait, associated with either modulation of gene expression or to the engagement of PrPC with a single ligand. In contrast, the GPI-anchored prion protein was shown to bind several extracellular and transmembrane ligands, which are required to endow that protein with the ability to play various roles in transmembrane signal transduction. In addition, differing sets of those ligands are available in cell type- and context-dependent scenarios. To account for such properties, we proposed that PrPC serves as a dynamic platform for the assembly of signaling modules at the cell surface, with widespread consequences for both physiology and behavior. The current review advances the hypothesis that the biological function of the prion protein is that of a cell surface scaffold protein, based on the striking similarities of its functional properties with those of scaffold proteins involved in the organization of intracellular signal transduction pathways. Those properties are: the ability to recruit spatially restricted sets of binding molecules involved in specific signaling; mediation of the crosstalk of signaling pathways; reciprocal allosteric regulation with binding partners; compartmentalized responses; dependence of signaling properties upon posttranslational modification; and stoichiometric requirements and/or oligomerization-dependent impact on signaling. The scaffold concept may contribute to novel approaches to the development of effective treatments to hitherto incurable neurodegenerative diseases, through informed modulation of prion protein-ligand interactions.
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Affiliation(s)
- Rafael Linden
- Laboratory of Neurogenesis, Institute of Biophysics, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
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Abstract
Prion diseases affect a wide range of mammal species and are caused by a misfolded self-propagating isoform (PrPSc) of the normal prion protein (PrPC). Distinct strains of prions exist and are operationally defined by differences in a heritable phenotype under controlled experimental transmission conditions. Prion strains can differ in incubation period, clinical signs of disease, tissue tropism, and host range. The mechanism by which a protein-only pathogen can encode strain diversity is only beginning to be understood. The prevailing hypothesis is that prion strain diversity is encoded by strain-specific conformations of PrPSc; however, strain-specific cellular cofactors have been identified in vitro that may also contribute to prion strain diversity. Although much progress has been made on understanding the etiological agent of prion disease, the relationship between the strain-specific properties of PrPSc and the resulting phenotype of disease in animals is poorly understood.
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Affiliation(s)
- Jason C Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska 68178
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Mays CE, Soto C. The stress of prion disease. Brain Res 2016; 1648:553-560. [PMID: 27060771 DOI: 10.1016/j.brainres.2016.04.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 04/01/2016] [Accepted: 04/05/2016] [Indexed: 01/31/2023]
Abstract
Prion diseases are fatal neurodegenerative disorders that include scrapie of sheep, bovine spongiform encephalopathy of cattle, chronic wasting disease of cervids, and Creutzfeldt-Jakob disease (CJD) of humans. The etiology for prion diseases can be infectious, sporadic, or hereditary. However, the common denominator for all types is the formation of a transmissible agent composed of a β-sheet-rich, misfolded version of the host-encoded prion protein (PrPC), known as PrPSc. PrPSc self-replicates through a template-assisted process that converts the α-helical conformation of PrPC into the disease-associated isoform. In parallel with PrPSc accumulation, spongiform change is pathologically observed in the central nervous system, where "holes" appear because of massive neuronal death. Here, we review the cellular pathways triggered in response to PrPSc formation and accumulation. Available data suggest that neuronal dysfunction and death may be caused by what originates as a cellular pro-survival response to chronic PrPSc accumulation. We also discuss what is known about the complex cross-talk between the endoplasmic reticulum stress components and the quality control pathways. Better knowledge about these processes may lead to innovative therapeutic strategies based on manipulating the stress response and its consequences for neurodegeneration. This article is part of a Special Issue entitled SI:ER stress.
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Affiliation(s)
- Charles E Mays
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX 77030, USA
| | - Claudio Soto
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX 77030, USA.
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Daude N, Gapeshina H, Dong B, Winship I, Westaway D. Neuroprotective properties of the PrP-like Shadoo glycoprotein assessed in the middle cerebral artery occlusion model of ischemia. Prion 2016; 9:376-93. [PMID: 26516793 PMCID: PMC4964864 DOI: 10.1080/19336896.2015.1105432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Biochemical similarities have been noted between the natively unstructured region of the cellular prion protein, PrPC, and a GPI-linked glycoprotein called Shadoo (Sho); these proteins are encoded by the Prnp and Sprn genes, respectively. Both proteins are expressed in the adult central nervous system and they share overlapping partners, including each other, in interactome studies. As prior studies have ascribed neuroprotective properties to the N-terminal region of PrPC, specifically the octarepeat region, we investigated Sho's neuroprotective properties. To this end we assessed Sho-null (Sprn0/0) and hemizygous (Sprn0/+) mice in the middle cerebral artery occlusion (MCAO) model versus wild type mice and also vs. transgene-rescued Sprn0/0-TgSprn mice. Sprn0/0 mice had a tendency to greater fragility in reaching endpoint and deficits in parameters including infarct volume and neurogenesis, with a reciprocal trend noted in transgene-rescued mice; however these effects did not reach significance. Loss of both PrPC and Sho immunostaining occurred in parallel to neuronal loss on the ipsilateral side of MCAO-lesioned animals; while focal elevations in immunostaining in the penumbra region were sometimes evident for PrPC, they were not noted for Sho. Our studies argue against discernible neuroprotective action of Sho in the genetic backgrounds used for this MCAO paradigm. Whether or not the positively charged N-terminal regions in Sho and PrPC fulfil different roles in vivo remains to be determined.
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Affiliation(s)
- Nathalie Daude
- a Center for Prion and Protein Folding Diseases; University of Alberta ; Edmonton , AB , Canada
| | - Hristina Gapeshina
- a Center for Prion and Protein Folding Diseases; University of Alberta ; Edmonton , AB , Canada
| | - Bin Dong
- b Neurochemical Research Unit; University of Alberta ; Edmonton , AB , Canada
| | - Ian Winship
- b Neurochemical Research Unit; University of Alberta ; Edmonton , AB , Canada
| | - David Westaway
- a Center for Prion and Protein Folding Diseases; University of Alberta ; Edmonton , AB , Canada
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Holcomb KM, Galloway NL, Mathiason CK, Antolin MF. Intra-host mathematical model of chronic wasting disease dynamics in deer (Odocoileus). Prion 2016; 10:377-390. [PMID: 27537196 PMCID: PMC5105936 DOI: 10.1080/19336896.2016.1189054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Bioassays of native cervid hosts have established the presence of infectious chronic wasting disease (CWD) prions in saliva, blood, urine, and feces of clinically diseased and pre-clinical infected deer. The intra-host trafficking of prions from the time of initial infection to shedding has been less well defined. We created a discrete-time compartmentalized model to simulate the misfolding catalysis, trafficking, and shedding of infectious prions throughout the organ systems of CWD-infected cervids. Using parameter values derived from experimental infections of North American deer (Odocoileus spp.), the exponential-based model predicts prion deposition over time with: 1) nervous tissues containing the highest deposition of prions at 20 months post-infection and 2) excreted fluids containing low levels of prions throughout infection with the highest numbers of prions predicted to be shed in saliva and feces (as high as 10 lethal doses (1.34 × 1029 prions) in 11–15 months). These findings are comparable to prion deposition described in literature as assayed by conventional and ultrasensitive amplification assays. The comparison of our model to published data suggests that highly sensitive assays (sPMCA, RT-QuIC, and bioassay) are appropriate for early prion detection in bodily fluids and secretions. The model provides a view of intra-host prion catalysis leading to pre-clinical shedding and provides a framework for continued development of antemortem diagnostic methods.
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Affiliation(s)
- Karen M Holcomb
- a Department of Biology , Colorado State University , Fort Collins , CO , USA
| | - Nathan L Galloway
- a Department of Biology , Colorado State University , Fort Collins , CO , USA
| | - Candace K Mathiason
- b Department of Microbiology , Immunology, and Pathology, Colorado State University , Fort Collins , CO , USA
| | - Michael F Antolin
- a Department of Biology , Colorado State University , Fort Collins , CO , USA
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Stocki P, Sawicki M, Mays CE, Hong SJ, Chapman DC, Westaway D, Williams DB. Inhibition of the FKBP family of peptidyl prolyl isomerases induces abortive translocation and degradation of the cellular prion protein. Mol Biol Cell 2016; 27:757-67. [PMID: 26764098 PMCID: PMC4803302 DOI: 10.1091/mbc.e15-10-0729] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/04/2016] [Indexed: 11/11/2022] Open
Abstract
Prion diseases are fatal neurodegenerative disorders for which there is no effective treatment. Because the cellular prion protein (PrP(C)) is required for propagation of the infectious scrapie form of the protein, one therapeutic strategy is to reduce PrP(C) expression. Recently FK506, an inhibitor of the FKBP family of peptidyl prolyl isomerases, was shown to increase survival in animal models of prion disease, with proposed mechanisms including calcineurin inhibition, induction of autophagy, and reduced PrP(C) expression. We show that FK506 treatment results in a profound reduction in PrP(C) expression due to a defect in the translocation of PrP(C) into the endoplasmic reticulum with subsequent degradation by the proteasome. These phenotypes could be bypassed by replacing the PrP(C) signal sequence with that of prolactin or osteopontin. In mouse cells, depletion of ER luminal FKBP10 was almost as potent as FK506 in attenuating expression of PrP(C). However, this occurred at a later stage, after translocation of PrP(C) into the ER. Both FK506 treatment and FKBP10 depletion were effective in reducing PrP(Sc) propagation in cell models. These findings show the involvement of FKBP proteins at different stages of PrP(C) biogenesis and identify FKBP10 as a potential therapeutic target for the treatment of prion diseases.
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Affiliation(s)
- Pawel Stocki
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Maxime Sawicki
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Charles E Mays
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada
| | - Seo Jung Hong
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Daniel C Chapman
- Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada Division of Neurology and Departments of Chemistry and Biochemistry, University of Alberta, Edmonton, AB T6G 2M8, Canada
| | - David B Williams
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada Department of Immunology, University of Toronto, Toronto, ON M5S 1A8, Canada
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De Mario A, Castellani A, Peggion C, Massimino ML, Lim D, Hill AF, Sorgato MC, Bertoli A. The prion protein constitutively controls neuronal store-operated Ca(2+) entry through Fyn kinase. Front Cell Neurosci 2015; 9:416. [PMID: 26578881 PMCID: PMC4623396 DOI: 10.3389/fncel.2015.00416] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/02/2015] [Indexed: 11/23/2022] Open
Abstract
The prion protein (PrPC) is a cell surface glycoprotein mainly expressed in neurons, whose misfolded isoforms generate the prion responsible for incurable neurodegenerative disorders. Whereas PrPC involvement in prion propagation is well established, PrPC physiological function is still enigmatic despite suggestions that it could act in cell signal transduction by modulating phosphorylation cascades and Ca2+ homeostasis. Because PrPC binds neurotoxic protein aggregates with high-affinity, it has also been proposed that PrPC acts as receptor for amyloid-β (Aβ) oligomers associated with Alzheimer’s disease (AD), and that PrPC-Aβ binding mediates AD-related synaptic dysfunctions following activation of the tyrosine kinase Fyn. Here, use of gene-encoded Ca2+ probes targeting different cell domains in primary cerebellar granule neurons (CGN) expressing, or not, PrPC, allowed us to investigate whether PrPC regulates store-operated Ca2+ entry (SOCE) and the implication of Fyn in this control. Our findings show that PrPC attenuates SOCE, and Ca2+ accumulation in the cytosol and mitochondria, by constitutively restraining Fyn activation and tyrosine phosphorylation of STIM1, a key molecular component of SOCE. This data establishes the existence of a PrPC-Fyn-SOCE triad in neurons. We also demonstrate that treating cerebellar granule and cortical neurons with soluble Aβ(1–42) oligomers abrogates the control of PrPC over Fyn and SOCE, suggesting a PrPC-dependent mechanizm for Aβ-induced neuronal Ca2+ dyshomeostasis.
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Affiliation(s)
- Agnese De Mario
- Department of Biomedical Science, University of Padova Padova, Italy
| | - Angela Castellani
- Department of Biomedical Science, University of Padova Padova, Italy
| | - Caterina Peggion
- Department of Biomedical Science, University of Padova Padova, Italy
| | | | - Dmitry Lim
- Department of Pharmaceutical Science, University of Piemonte Orientale Novara, Italy
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University Melbourne, VIC, Australia
| | - M Catia Sorgato
- Department of Biomedical Science, University of Padova Padova, Italy ; CNR Neuroscience Institute, University of Padova Padova, Italy
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Prion Infectivity Plateaus and Conversion to Symptomatic Disease Originate from Falling Precursor Levels and Increased Levels of Oligomeric PrPSc Species. J Virol 2015; 89:12418-26. [PMID: 26423957 DOI: 10.1128/jvi.02142-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 09/25/2015] [Indexed: 01/17/2023] Open
Abstract
UNLABELLED In lethal prion neurodegenerative diseases, misfolded prion proteins (PrP(Sc)) replicate by redirecting the folding of the cellular prion glycoprotein (PrP(C)). Infections of different durations can have a subclinical phase with constant levels of infectious particles, but the mechanisms underlying this plateau and a subsequent exit to overt clinical disease are unknown. Using tandem biophysical techniques, we show that attenuated accumulation of infectious particles in presymptomatic disease is preceded by a progressive fall in PrP(C) level, which constricts replication rate and thereby causes the plateau effect. Furthermore, disease symptoms occurred at the threshold associated with increasing levels of small, relatively less protease-resistant oligomeric prion particles (oPrP(Sc)). Although a hypothetical lethal isoform of PrP cannot be excluded, our data argue that diminishing residual PrP(C) levels and continuously increasing levels of oPrP(Sc) are crucial determinants in the transition from presymptomatic to symptomatic prion disease. IMPORTANCE Prions are infectious agents that cause lethal brain diseases; they arise from misfolding of a cell surface protein, PrP(C) to a form called PrP(Sc). Prion infections can have long latencies even though there is no protective immune response. Accumulation of infectious prion particles has been suggested to always reach the same plateau in the brain during latent periods, with clinical disease only occurring when hypothetical toxic forms (called PrP(L) or TPrP) begin to accumulate. We show here that infectivity plateaus arise because PrP(C) precursor levels become downregulated and that the duration of latent periods can be accounted for by the level of residual PrP(C), which transduces a toxic effect, along with the amount of oligomeric forms of PrP(Sc).
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Abstract
Aggregation of misfolded host proteins in the central nervous system is believed to be important in the pathogenic process in several neurodegenerative diseases of humans, including prion diseases, Alzheimer’s disease, and Parkinson’s disease. In these diseases, protein misfolding and aggregation appear to expand through a process of seeded polymerization. Prion diseases occur in both humans and animals and are experimentally transmissible orally or by injection, thus providing a controllable model of other neurodegenerative protein misfolding diseases. In rodents and ruminants, prion disease has a slow course, lasting months to years. Although prion infectivity has been detected in brain tissue at 3 to 4 weeks postinfection (p.i.), the details of early prion replication in the brain are not well understood. Here we studied the localization and quantitation of PrPSc generation in vivo starting at 30 min postmicroinjection of scrapie into the brain. In C57BL mice at 3 days p.i., generation of new PrPSc was detected by immunohistochemistry and immunoblot assays, and at 7 days p.i., new generation was confirmed by real-time quaking-induced conversion assay. The main site of new PrPSc generation was near the outer basement membrane of small and medium blood vessels. The finding and localization of replication at this site so early after injection have not been reported previously. This predominantly perivascular location suggested that structural components of the blood vessel basement membrane or perivascular astrocytes might act as cofactors in the initial generation of PrPSc. The location of PrPSc replication at the basement membrane also implies a role for the brain interstitial fluid drainage in the early infection process. Neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and prion diseases, of humans are characterized by misfolding and aggregation of certain proteins, resulting in the destruction of brain tissue. In these diseases, the damage process spreads progressively within the central nervous system, but only prion diseases are known to be transmissible between individuals. Here we used microinjection of infectious prion protein (PrPSc) into the mouse brain to model early events of iatrogenic prion transmission via surgical instruments or tissue grafts. At 3 and 7 days postinjection, we detected the generation of new PrPSc, mostly on the outer walls of blood vessels near the injection site. This location and very early replication were surprising and unique. Perivascular prion replication suggested the transport of injected PrPSc via brain interstitial fluid to the basement membranes of blood vessels, where interactions with possible cofactors made by astrocytes or endothelia might facilitate the earliest cycles of prion infection.
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Double-Edge Sword of Sustained ROCK Activation in Prion Diseases through Neuritogenesis Defects and Prion Accumulation. PLoS Pathog 2015; 11:e1005073. [PMID: 26241960 PMCID: PMC4524729 DOI: 10.1371/journal.ppat.1005073] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 07/07/2015] [Indexed: 01/05/2023] Open
Abstract
In prion diseases, synapse dysfunction, axon retraction and loss of neuronal polarity precede neuronal death. The mechanisms driving such polarization defects, however, remain unclear. Here, we examined the contribution of RhoA-associated coiled-coil containing kinases (ROCK), key players in neuritogenesis, to prion diseases. We found that overactivation of ROCK signaling occurred in neuronal stem cells infected by pathogenic prions (PrPSc) and impaired the sprouting of neurites. In reconstructed networks of mature neurons, PrPSc-induced ROCK overactivation provoked synapse disconnection and dendrite/axon degeneration. This overactivation of ROCK also disturbed overall neurotransmitter-associated functions. Importantly, we demonstrated that beyond its impact on neuronal polarity ROCK overactivity favored the production of PrPSc through a ROCK-dependent control of 3-phosphoinositide-dependent kinase 1 (PDK1) activity. In non-infectious conditions, ROCK and PDK1 associated within a complex and ROCK phosphorylated PDK1, conferring basal activity to PDK1. In prion-infected neurons, exacerbated ROCK activity increased the pool of PDK1 molecules physically interacting with and phosphorylated by ROCK. ROCK-induced PDK1 overstimulation then canceled the neuroprotective α-cleavage of normal cellular prion protein PrPC by TACE α-secretase, which physiologically precludes PrPSc production. In prion-infected cells, inhibition of ROCK rescued neurite sprouting, preserved neuronal architecture, restored neuronal functions and reduced the amount of PrPSc. In mice challenged with prions, inhibition of ROCK also lowered brain PrPSc accumulation, reduced motor impairment and extended survival. We conclude that ROCK overactivation exerts a double detrimental effect in prion diseases by altering neuronal polarity and triggering PrPSc accumulation. Eventually ROCK emerges as therapeutic target to combat prion diseases. Transmissible Spongiform Encephalopathies (TSEs), commonly named prion diseases, are caused by deposition in the brain of pathogenic prions PrPSc that trigger massive neuronal death. Because of our poor understanding of the mechanisms sustaining prion-induced neurodegeneration, there is to date no effective medicine to combat TSEs. The current study demonstrates that ROCK kinases are overactivated in prion-infected cells and contribute to prion pathogenesis at two levels. First, PrPSc-induced ROCK overactivation affects neuronal polarity with synapse disconnection, axon/dendrite degradation, and disturbs neuronal functions. Second, ROCK overactivity amplifies the production of pathogenic prions. The pharmacological inhibition of ROCK protects diseased neurons from PrPSc toxicity by preserving neuronal architecture and functions and lowering PrPSc level. Inhibition of ROCK in prion-infected mice reduces brain PrPSc levels, improves motor activity and extends lifespan. This study opens up new avenues to design ROCK-based therapeutic strategies to fight TSEs.
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49
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Petersen RB, Lissemore FM, Appleby B, Aggarwal N, Boyatzis R, Casadesus G, Cummings J, Jack A, Perry G, Safar J, Sajatovic M, Surewicz WK, Wang Y, Whitehouse P, Lerner A. From Neurodegeneration to Brain Health: An Integrated Approach. J Alzheimers Dis 2015; 46:271-83. [DOI: 10.3233/jad-150043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Robert B. Petersen
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
| | | | - Brian Appleby
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
- Department of Psychiatry, Case Western Reserve University, Cleveland, OH, USA
- Department of Neurology, University Hospitals Case Medical Center, Cleveland, OH, USA
| | - Neelum Aggarwal
- Department of Neurology, Rush University Medical Center, Chicago, IL, USA
| | - Richard Boyatzis
- Departments of Organizational Behavior, Cognitive Science, and Psychology, Case Western Reserve University, Cleveland, OH, USA
| | | | - Jeff Cummings
- Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, USA
| | - Anthony Jack
- Department of Philosophy, Case Western Reserve University, Cleveland, OH, USA
| | - George Perry
- Department of Biology, University of Texas, San Antonio, TX, USA
| | - Jiri Safar
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
| | - Martha Sajatovic
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
- Department of Psychiatry, Case Western Reserve University, Cleveland, OH, USA
| | - Witold K. Surewicz
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Yanming Wang
- Departments of Radiology, Chemistry, and Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Peter Whitehouse
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
| | - Alan Lerner
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
- Department of Neurology, University Hospitals Case Medical Center, Cleveland, OH, USA
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50
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Wustoni S, Hideshima S, Kuroiwa S, Nakanishi T, Hashimoto M, Mori Y, Osaka T. Sensitive electrical detection of human prion proteins using field effect transistor biosensor with dual-ligand binding amplification. Biosens Bioelectron 2015; 67:256-62. [DOI: 10.1016/j.bios.2014.08.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/08/2014] [Accepted: 08/08/2014] [Indexed: 11/16/2022]
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