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Eigenbrod S, Frick P, Bertsch U, Mitteregger-Kretzschmar G, Mielke J, Maringer M, Piening N, Hepp A, Daude N, Windl O, Levin J, Giese A, Sakthivelu V, Tatzelt J, Kretzschmar H, Westaway D. Substitutions of PrP N-terminal histidine residues modulate scrapie disease pathogenesis and incubation time in transgenic mice. PLoS One 2017; 12:e0188989. [PMID: 29220360 PMCID: PMC5722314 DOI: 10.1371/journal.pone.0188989] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 11/16/2017] [Indexed: 12/31/2022] Open
Abstract
Prion diseases have been linked to impaired copper homeostasis and copper induced-oxidative damage to the brain. Divalent metal ions, such as Cu2+ and Zn2+, bind to cellular prion protein (PrPC) at octapeptide repeat (OR) and non-OR sites within the N-terminal half of the protein but information on the impact of such binding on conversion to the misfolded isoform often derives from studies using either OR and non-OR peptides or bacterially-expressed recombinant PrP. Here we created new transgenic mouse lines expressing PrP with disrupted copper binding sites within all four histidine-containing OR's (sites 1-4, H60G, H68G, H76G, H84G, "TetraH>G" allele) or at site 5 (composed of residues His-95 and His-110; "H95G" allele) and monitored the formation of misfolded PrP in vivo. Novel transgenic mice expressing PrP(TetraH>G) at levels comparable to wild-type (wt) controls were susceptible to mouse-adapted scrapie strain RML but showed significantly prolonged incubation times. In contrast, amino acid replacement at residue 95 accelerated disease progression in corresponding PrP(H95G) mice. Neuropathological lesions in terminally ill transgenic mice were similar to scrapie-infected wt controls, but less severe. The pattern of PrPSc deposition, however, was not synaptic as seen in wt animals, but instead dense globular plaque-like accumulations of PrPSc in TgPrP(TetraH>G) mice and diffuse PrPSc deposition in (TgPrP(H95G) mice), were observed throughout all brain sections. We conclude that OR and site 5 histidine substitutions have divergent phenotypic impacts and that cis interactions between the OR region and the site 5 region modulate pathogenic outcomes by affecting the PrP globular domain.
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Affiliation(s)
- Sabina Eigenbrod
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Petra Frick
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Uwe Bertsch
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | | | - Janina Mielke
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Marko Maringer
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Niklas Piening
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Alexander Hepp
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Nathalie Daude
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Otto Windl
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Johannes Levin
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Armin Giese
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - Vignesh Sakthivelu
- Department of Metabolic Biochemistry/Neurobiochemistry, Adolf Butenandt Institute, Ludwig Maximilians University, Munich, Germany
| | - Jörg Tatzelt
- Department of Metabolic Biochemistry/Neurobiochemistry, Adolf Butenandt Institute, Ludwig Maximilians University, Munich, Germany
| | - Hans Kretzschmar
- Center for Neuropathology and Prion Research, Ludwig Maximilians University, Munich, Germany
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
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Abstract
Prions are the causative infectious agents of transmissible spongiform encephalopathies (TSEs). They are thought to arise from misfolding and aggregation of the prion protein (PrP). In serial transmission protein misfolding cyclic amplification (sPMCA) experiments, newly formed misfolded and proteinase K-resistant PrP (PrPres) catalysed the structural conversion of cellular prion protein (PrP(C)) as efficiently as PrP(Sc) from the brain of scrapie-infected (263K) hamsters confirming an autocatalytic misfolding cascade as postulated by the prion hypothesis. However, the fact that PrPres generated in vitro was associated with approximately 10 times less infectivity than an equivalent quantity of brain-derived PrP(Sc) casts doubt on the "protein-only" hypothesis of prion propagation and backs theories that suggest there are additional molecular species of infectious PrP or other agent-associated factors. By combining sPMCA with prion delivery on suitable carrier particles we were able to resolve the apparent discrepancy between the amount of PrPres and infectivity which we were then able to relate to differences in the size distribution of PrP aggregates and consecutive differences in regard to biological clearance. These findings demonstrate that we have designed an experimental set-up yielding in vitro generated prions that are indistinguishable from prions isolated from scrapie-infected hamster brain in terms of proteinase K resistance, autocatalytic conversion activity, and - most notably - specific biological infectivity.
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Affiliation(s)
- Petra Weber
- Centre for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 23, 81377 Munich, Germany.
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Weber P, Giese A, Piening N, Mitteregger G, Thomzig A, Beekes M, Kretzschmar HA. Cell-free formation of misfolded prion protein with authentic prion infectivity. Proc Natl Acad Sci U S A 2006; 103:15818-23. [PMID: 17030802 PMCID: PMC1635086 DOI: 10.1073/pnas.0605608103] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Prion propagation has been modeled in vitro; however, the low infectious titer of PrP(Sc) thus generated has cast doubt on the "protein-only" hypothesis. Here we show that prion delivery on suitable nitrocellulose carrier particles abrogates the apparent dissociation of PrP(Sc) and infectivity. Misfolded prion protein generated by protein misfolding cyclic amplification is as infectious as authentic brain-derived PrP(Sc) provided that confounding effects related to differences in the size distribution of prion protein aggregates generated in vitro and consecutive differences in regard to biological clearance are abolished.
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Affiliation(s)
- Petra Weber
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 23, 81377 Munich, Germany; and
| | - Armin Giese
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 23, 81377 Munich, Germany; and
- To whom correspondence may be addressed. E-mail:
or
| | - Niklas Piening
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 23, 81377 Munich, Germany; and
| | - Gerda Mitteregger
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 23, 81377 Munich, Germany; and
| | - Achim Thomzig
- Transmissible Spongiform Encephalopathies, Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany
| | - Michael Beekes
- Transmissible Spongiform Encephalopathies, Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany
| | - Hans A. Kretzschmar
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 23, 81377 Munich, Germany; and
- To whom correspondence may be addressed. E-mail:
or
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Abstract
Prion diseases are caused by a unique type of infectious agent, which is thought to consist of a misfolded beta-sheeted form of the alpha-helical cellular prion protein (PrPC). This misfolded isoform (PrPSc) tends to form insoluble amyloid-like aggregates, impeding classical structural analysis by X-ray crystallography or NMR. Intermolecular crosslinking may provide a means of stabilizing notoriously elusive oligomers for further analysis and may be used for analyzing aggregate architecture by characterising intermolecular contact sites. Using a photo-induced crosslinking method (PICUP), aggregates of recombinant PrP (rPrP) and PrPSc were linked at interacting surfaces via amino acid side chains. The degree of crosslinking within PrP aggregates was adjustable using varying light intensities and could efficiently be monitored by fluorescence correlation spectroscopy. Specific intermolecular crosslinking of PrPSc molecules was achieved even in crude brain homogenate. Functional studies showed that stabilized aggregates of rPrP did not loose their capacity to induce further protein aggregation and crosslinking of PrPSc did not alter significantly the level of infectivity, indicating that photo-induced covalent linkage of PrPSc does not destruct surfaces important for prion propagation.
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Affiliation(s)
- Niklas Piening
- Zentrum für Neuropathologie und Prionforschung, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 23, 81377 München, Germany
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Piening N, Nonno R, Di Bari M, Walter S, Windl O, Agrimi U, Kretzschmar HA, Bertsch U. Conversion efficiency of bank vole prion protein in vitro is determined by residues 155 and 170, but does not correlate with the high susceptibility of bank voles to sheep scrapie in vivo. J Biol Chem 2006; 281:9373-84. [PMID: 16455657 DOI: 10.1074/jbc.m512239200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The misfolded infectious isoform of the prion protein (PrP(Sc)) is thought to replicate in an autocatalytic manner by converting the cellular form (PrP(C)) into its pathogenic folding variant. The similarity in the amino acid sequence of PrP(C) and PrP(Sc) influences the conversion efficiency and is considered as the major determinant for the species barrier. We performed in vitro conversion reactions on wild-type and mutated PrP(C) to determine the role of the primary sequence for the high susceptibility of bank voles to scrapie. Different conversion efficiencies obtained with bank vole and mouse PrP(C) in reactions with several prion strains were due to differences at amino acid residues 155 and 170. However, the conversion efficiencies obtained with mouse and vole PrP(C) in reactions with sheep scrapie did not correlate with the susceptibility of the respective species to this prion strain. This discrepancy between in vitro and in vivo data may indicate that at least in the case of scrapie transmission to bank voles additional host factors can strongly modulate the species barrier. Furthermore, in vitro conversion reactions with different prion strains revealed that the degree of alteration of the conversion efficiency induced by amino acid exchanges was varying according to the prion strain. These results support the assumption that the repertoire of conformations adopted by a certain PrP(C) primary sequence is decisive for its convertibility to the strain-specific PrP(Sc) conformation.
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Affiliation(s)
- Niklas Piening
- Zentrum für Neuropathologie und Prionforschung, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 23, 81377 Munich, Germany
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Piening N, Weber P, Giese A, Kretzschmar H. Breakage of PrP aggregates is essential for efficient autocatalytic propagation of misfolded prion protein. Biochem Biophys Res Commun 2005; 326:339-43. [PMID: 15582583 DOI: 10.1016/j.bbrc.2004.11.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Indexed: 11/18/2022]
Abstract
The conversion of cellular prion protein (PrP(C)) to the disease-associated misfolded isoform (PrP(Sc)) is an essential process for prion replication. This structural conversion can be modelled in protein misfolding cyclic amplification (PMCA) reactions in which PrP(Sc) is inoculated into healthy hamster brain homogenate, followed by cycles of incubation and sonication. In serial transmission PMCA experiments it has recently been shown that the protease-resistant PrP obtained in vitro (PrPres) is generated by an autocatalytic mechanism. Here, serial transmission PMCA experiments were compared with serial transmission reactions lacking the sonication steps. We achieved approximately 200,000-fold PrPres amplification by PMCA. In contrast, although initial amplification was comparable to PMCA reactions, PrPres levels quickly dropped below detection limit when samples were not subjected to ultrasound. These results indicate that aggregate breakage is essential for efficient autocatalytic amplification of misfolded prion protein and suggest an important role of aggregate breakage in prion propagation.
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Affiliation(s)
- Niklas Piening
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 23, 81377 Munich, Germany
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