1
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Lee CH, Saw JE, Chen EHL, Wang CH, Uchihashi T, Chen RPY. The Positively Charged Cluster in the N-terminal Disordered Region may Affect Prion Protein Misfolding: Cryo-EM Structure of Hamster PrP(23-144) Fibrils. J Mol Biol 2024; 436:168576. [PMID: 38641239 DOI: 10.1016/j.jmb.2024.168576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/09/2024] [Accepted: 04/12/2024] [Indexed: 04/21/2024]
Abstract
Prions, the misfolding form of prion proteins, are contagious proteinaceous macromolecules. Recent studies have shown that infectious prion fibrils formed in the brain and non-infectious fibrils formed from recombinant prion protein in a partially denaturing condition have distinct structures. The amyloid core of the in vitro-prepared non-infectious fibrils starts at about residue 160, while that of infectious prion fibrils formed in the brain involves a longer sequence (residues ∼90-230) of structural conversion. The C-terminal truncated prion protein PrP(23-144) can form infectious fibrils under certain conditions and cause disease in animals. In this study, we used cryogenic electron microscopy (cryo-EM) to resolve the structure of hamster sHaPrP(23-144) fibrils prepared at pH 3.7. This 2.88 Å cryo-EM structure has an amyloid core covering residues 94-144. It comprises two protofilaments, each containing five β-strands arranged as a long hairpin plus an N-terminal β-strand. This N-terminal β-strand resides in a positively charged cluster region (named PCC2; sequence 96-111), which interacts with the turn region of the opposite protofilaments' hairpin to stabilize the fibril structure. Interestingly, this sHaPrP(23-144) fibril structure differs from a recently reported structure formed by the human or mouse counterpart at pH 6.5. Moreover, sHaPrP(23-144) fibrils have many structural features in common with infectious prions. Whether this structure is infectious remains to be determined. More importantly, the sHaPrP(23-144) structure is different from the sHaPrP(108-144) fibrils prepared in the same fibrillization buffer, indicating that the N-terminal disordered region, possibly the positively charged cluster, influences the misfolding pathway of the prion protein.
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Affiliation(s)
- Chih-Hsuan Lee
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei 115, Taiwan
| | - Jing-Ee Saw
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei 106, Taiwan
| | - Eric H-L Chen
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei 115, Taiwan
| | - Chun-Hsiung Wang
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei 115, Taiwan
| | - Takayuki Uchihashi
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan; Institute for Glyco-core Research (iGCORE), Nagoya University, Nagoya 464-8602, Japan; Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Rita P-Y Chen
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei 106, Taiwan; Neuroscience Program of Academia Sinica, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei 115, Taiwan.
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2
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Tavşanlı A, Balta B. Conversion of Helix 1 into a Loop in Prion Protein Misfolding. ACS OMEGA 2023; 8:7191-7200. [PMID: 36844589 PMCID: PMC9948551 DOI: 10.1021/acsomega.3c00212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Cellular prion protein PrPC consists of three α-helices, one β-sheet, and an unstructured N-terminal domain. Misfolding of this protein into the scrapie form (PrPSc) increases dramatically the β-sheet content. H1 is the most stable helix on PrPC and contains an unusual number of hydrophilic amino acids. Its fate in PrPSc is not clear. We performed replica exchange molecular dynamics simulations on H1 alone, H1 together with an N-terminally flanking H1B1 loop and H1 in complex with other hydrophilic regions of the prion protein. In the presence of the H99SQWNKPSKPKTNMK113 sequence, H1 is almost completely converted to a loop structure stabilized by a network of salt bridges. On the other hand, H1 retains its helical structure alone or together with the other sequences considered in this study. We carried out an additional simulation by restraining the distance between the two ends of H1, mimicking a possible geometric restriction by the rest of the protein. Even though the loop was the major conformation, a significant amount of helical structure was also observed. This suggests that the interaction with H99SQWNKPSKPKTNMK113 is necessary for complete helix-to-loop conversion.
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3
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Jheng CP, Lee CI. Combination of structure-based virtual screening, molecular docking and molecular dynamics approaches for the discovery of anti-prion fibril flavonoids. Front Mol Biosci 2023; 9:1088733. [PMID: 36685276 PMCID: PMC9849400 DOI: 10.3389/fmolb.2022.1088733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/16/2022] [Indexed: 01/06/2023] Open
Abstract
Prion diseases are a group of rare neurodegenerative diseases caused by the structural conversion of cellular prion into Scrapie prion resulting aggregated fibrils. Therapy of prion diseases has been developed for several decades, especially drug designs based on the structure of prion monomers. Unfortunately, none of the designed anti-prion drugs function well clinically. To fight against prion fibrils, a drug design based on the precise structure of mammalian prion fibrils is highly required. Fortunately, based on the advantage of newly advanced cryo-electron microscopy (cryo-EM) in the deconvolution of large complexes, three prion fibril structures were resolved in the last 2 years. Based on the cryo-EM solved prion fibril structures, we are able to find some molecules fighting against prion fibrils. Quercetin, one flavonoid molecule in the polyphenol group, has been found to disaggregate the prion fibrils in vitro. In this study, we performed the molecular docking and molecular dynamics simulation on quercetin-like molecules possessing pharmacological properties to evaluate the anti-prion ability of tested molecules. As a result, four quercetin-like molecules interact with prion fibril and decrease the β-strand content by converting some β-strands into loop and helical structures to disintegrate the existing fibril structure. The results of this study are significant in the treatment of prion diseases, and the approaches used in this study are applicable to other amyloid diseases.
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Affiliation(s)
- Cheng-Ping Jheng
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan
| | - Cheng-I Lee
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan,Center for Nano Bio-Detections, National Chung Cheng University, Chia-Yi, Taiwan,Center for Innovative Research on Aging Society (CIRAS), National Chung Cheng University, Chia-Yi, Taiwan,*Correspondence: Cheng-I Lee,
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4
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Chen EHL, Kao HW, Lee CH, Huang JYC, Wu KP, Chen RPY. 2.2 Å Cryo-EM Tetra-Protofilament Structure of the Hamster Prion 108-144 Fibril Reveals an Ordered Water Channel in the Center. J Am Chem Soc 2022; 144:13888-13894. [PMID: 35857020 DOI: 10.1021/jacs.2c05479] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fibrils of the hamster prion peptide (sHaPrP, sequence 108-144) were prepared in an acidic solution, and their structure was solved by cryogenic electron microscopy with a resolution of 2.23 Å based on the gold-standard Fourier shell correlation (FSC) curve. The fibril has a novel architecture that has never been found in other amyloid fibrils. Each fibril is assembled by four protofilaments (PFs) and has an ordered water channel in the center. Each protofilament contains three β-strands (125-130, 133-135, and 138-141) arranged in an "R"-shaped construct. The structural data indicate that these three β-strand segments are the most amyloidogenic region of the prion peptide/protein and might be the site of nucleation during fibrillization under conditions without denaturants.
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Affiliation(s)
- Eric H-L Chen
- Institute of Biological Chemistry, Academia Sinica, No. 128, Section 2, Academia Road, Nankang, Taipei 115, Taiwan
| | - Hsi-Wen Kao
- Institute of Biological Chemistry, Academia Sinica, No. 128, Section 2, Academia Road, Nankang, Taipei 115, Taiwan
| | - Chih-Hsuan Lee
- Institute of Biological Chemistry, Academia Sinica, No. 128, Section 2, Academia Road, Nankang, Taipei 115, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
| | - Jessica Y C Huang
- Institute of Biological Chemistry, Academia Sinica, No. 128, Section 2, Academia Road, Nankang, Taipei 115, Taiwan
| | - Kuen-Phon Wu
- Institute of Biological Chemistry, Academia Sinica, No. 128, Section 2, Academia Road, Nankang, Taipei 115, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
| | - Rita P-Y Chen
- Institute of Biological Chemistry, Academia Sinica, No. 128, Section 2, Academia Road, Nankang, Taipei 115, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan.,Neuroscience Program of Academia Sinica, Academia Sinica, No. 128, Section 2, Academia Road, Nankang, Taipei 115, Taiwan
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5
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Chu BK, Tsai R, Hung C, Kuo Y, Chen EH, Chiang Y, Chan SI, Chen RP. Location of the cross‐β structure in prion fibrils: A search by seeding and electron spin resonance spectroscopy. Protein Sci 2022; 31:e4326. [DOI: 10.1002/pro.4326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 12/19/2022]
Affiliation(s)
- Brett K.‐Y. Chu
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Ruei‐Fong Tsai
- Department of Chemistry National Tsing Hua University Hsinchu Taiwan
| | - Chien‐Lun Hung
- Department of Chemistry National Tsing Hua University Hsinchu Taiwan
| | - Yun‐Hsuan Kuo
- Department of Chemistry National Tsing Hua University Hsinchu Taiwan
| | - Eric H.‐L. Chen
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
| | - Yun‐Wei Chiang
- Department of Chemistry National Tsing Hua University Hsinchu Taiwan
| | - Sunney I. Chan
- Department of Chemistry National Taiwan University Taipei Taiwan
- Institute of Chemistry Academia Sinica Taipei Taiwan
| | - Rita P.‐Y. Chen
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
- Institute of Biochemical Sciences National Taiwan University Taipei Taiwan
- Neuroscience Program of Academia Sinica Academia Sinica Taipei Taiwan
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6
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James EI, Murphree TA, Vorauer C, Engen JR, Guttman M. Advances in Hydrogen/Deuterium Exchange Mass Spectrometry and the Pursuit of Challenging Biological Systems. Chem Rev 2021; 122:7562-7623. [PMID: 34493042 PMCID: PMC9053315 DOI: 10.1021/acs.chemrev.1c00279] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Solution-phase hydrogen/deuterium
exchange (HDX) coupled to mass
spectrometry (MS) is a widespread tool for structural analysis across
academia and the biopharmaceutical industry. By monitoring the exchangeability
of backbone amide protons, HDX-MS can reveal information about higher-order
structure and dynamics throughout a protein, can track protein folding
pathways, map interaction sites, and assess conformational states
of protein samples. The combination of the versatility of the hydrogen/deuterium
exchange reaction with the sensitivity of mass spectrometry has enabled
the study of extremely challenging protein systems, some of which
cannot be suitably studied using other techniques. Improvements over
the past three decades have continually increased throughput, robustness,
and expanded the limits of what is feasible for HDX-MS investigations.
To provide an overview for researchers seeking to utilize and derive
the most from HDX-MS for protein structural analysis, we summarize
the fundamental principles, basic methodology, strengths and weaknesses,
and the established applications of HDX-MS while highlighting new
developments and applications.
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Affiliation(s)
- Ellie I James
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Taylor A Murphree
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Clint Vorauer
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - John R Engen
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
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7
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Chen EHL, Lin KM, Sang JC, Ho MR, Lee CH, Shih O, Su CJ, Yeh YQ, Jeng US, Chen RPY. Condition-dependent structural collapse in the intrinsically disordered N-terminal domain of prion protein. IUBMB Life 2021; 74:780-793. [PMID: 34288372 DOI: 10.1002/iub.2528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/25/2021] [Accepted: 06/27/2021] [Indexed: 11/06/2022]
Abstract
Prion protein is composed of a structure-unsolved N-terminal domain and a globular C-terminal domain. Under limited trypsin digestion, mouse recombinant prion protein can be cleaved into two parts at residue Lys105. Here, we termed these two fragments as the N-domain (sequence 23-105) and the C-domain (sequence 106-230). In this study, the structural properties of the N-domain, the C-domain, and the full-length protein were explored using small-angle X-ray scattering, analytical ultracentrifugation, circular dichroism spectroscopy, and the 8-anilino-1-naphthalenesulfonic acid binding assay. The conformation and size of the prion protein were found to change sensitively under the solvent conditions. The positive residues in the sequence 23-99 of the N-domain were found to be responsible for the enhanced flexibility with the salt concentration reduced below 5 mM. The C-domain containing a hydrophobic patch tends to unfold and aggregate during a salt-induced structural collapse. The N-domain collapsed together with the C-domain at pH 5.2, whereas it collapsed independently at pH 4.2. The positively charged cluster (sequence 100-105) in the N-domain contributed to protecting the exposed hydrophobic surface of the C-domain.
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Affiliation(s)
- Eric H-L Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Kuei-Ming Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Jason C Sang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Meng-Ru Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chih-Hsuan Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Orion Shih
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Chun-Jen Su
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Yi-Qi Yeh
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - U-Ser Jeng
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan.,Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Rita P-Y Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.,Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan
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8
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Sangeetham SB, Engelke AD, Fodor E, Krausz SL, Tatzelt J, Welker E. The G127V variant of the prion protein interferes with dimer formation in vitro but not in cellulo. Sci Rep 2021; 11:3116. [PMID: 33542378 PMCID: PMC7862613 DOI: 10.1038/s41598-021-82647-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/10/2020] [Indexed: 01/30/2023] Open
Abstract
Scrapie prion, PrPSc, formation is the central event of all types of transmissible spongiform encephalopathies (TSEs), while the pathway with possible intermediates and their mechanism of formation from the normal isoform of prion (PrP), remains not fully understood. Recently, the G127V variant of the human PrP is reported to render the protein refractory to transmission of TSEs, via a yet unknown mechanism. Molecular dynamics studies suggested that this mutation interferes with the formation of PrP dimers. Here we analyze the dimerization of 127G and 127VPrP, in both in vitro and a mammalian cell culture system. Our results show that while molecular dynamics may capture the features affecting dimerization in vitro, G127V inhibiting dimer formation of PrP, these are not evidenced in a more complex cellular system.
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Affiliation(s)
- Sudheer Babu Sangeetham
- Institute of Biochemistry, Biological Research Centre, Szeged, 6726, Hungary
- Doctoral School of Multidisciplinary Medical Sciences, University of Szeged, Dugonics square 13, Szeged, 6720, Hungary
| | - Anna Dorothee Engelke
- Department Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, 44801, Bochum, Germany
- Department of Neurology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - Elfrieda Fodor
- Institute of Biochemistry, Biological Research Centre, Szeged, 6726, Hungary
| | - Sarah Laura Krausz
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, 1117, Hungary
- School of Ph.D. Studies, Semmelweis University, Budapest, 1085, Hungary
- Aktogen Hungary Ltd., Kecskemét, 6000, Hungary
| | - Jörg Tatzelt
- Department Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, 44801, Bochum, Germany.
- Cluster of Excellence RESOLV, Bochum, Germany.
| | - Ervin Welker
- Institute of Biochemistry, Biological Research Centre, Szeged, 6726, Hungary.
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, 1117, Hungary.
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9
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Spagnolli G, Rigoli M, Novi Inverardi G, Codeseira YB, Biasini E, Requena JR. Modeling PrP Sc Generation Through Deformed Templating. Front Bioeng Biotechnol 2020; 8:590501. [PMID: 33123520 PMCID: PMC7573312 DOI: 10.3389/fbioe.2020.590501] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 09/14/2020] [Indexed: 12/18/2022] Open
Abstract
Deformed templating is the process by which self-replicating protein conformations with a given cross-β folding pattern can seed formation of an alternative self-replicating state with different cross-β folding pattern. In particular, uninfectious but propagative PrP amyloid can transform into a bona fide infectious conformer, PrPSc through deformed templating. The process can take many rounds of replication (if taking place in vitro) or even several passages of the evolving PrP conformers through successive brains if in vivo, through experimental transmission. In all cases, deformed templating involves a forced conversion in which there is a mismatch between the template and the substrate and/or the templating environment, typically a recombinant PrP amyloid, adept at converting recombinant PrP under denaturing conditions (e.g., presence of chaotropic agents), encountering a glycosylated, GPI-anchored PrPC substrate under physiological conversion conditions. Deformed templating is characterized by emergence of intermediate conformers that exhibit biochemical characteristics that are intermediate between those of the initial PrP amyloid and the final PrPSc conformers. Here, we took advantage of the recent elucidation of the structure of a PrP amyloid by cryo-EM and the availability of a physically plausible atomistic model of PrPSc that we have recently proposed. Using modeling and Molecular Dynamics (MD) approaches, we built a complete molecular modelization of deformed templating, including an atomistic model of a glycosylated intermediate conformer and a modified model of PrPSc. Among other unanticipated outcomes, our results show that fully glycosylated PrP can be stacked in-register, and how 4-rung β-solenoid (4RβS) PrP architectures can share key structural motifs with parallel-in register intermolecular sheet (PIRIBS) PrP amyloids. Our results shed light on the mechanisms of prion replication.
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Affiliation(s)
- Giovanni Spagnolli
- Department of Cellular, Computational and Integrative Biology, Centre for Integrative Biology, University of Trento, Trento, Italy.,Dulbecco Telethon Institute, University of Trento, Trento, Italy
| | - Marta Rigoli
- Department of Cellular, Computational and Integrative Biology, Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Giovanni Novi Inverardi
- Department of Cellular, Computational and Integrative Biology, Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Yaiza B Codeseira
- CIMUS Biomedical Research Institute, University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
| | - Emiliano Biasini
- Department of Cellular, Computational and Integrative Biology, Centre for Integrative Biology, University of Trento, Trento, Italy.,Dulbecco Telethon Institute, University of Trento, Trento, Italy
| | - Jesús R Requena
- CIMUS Biomedical Research Institute, University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
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10
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Spagnolli G, Requena JR, Biasini E. Understanding prion structure and conversion. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:19-30. [PMID: 32958233 DOI: 10.1016/bs.pmbts.2020.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Since their original identification, prions have represented enigmatic agents that defy the classical concept of genetic inheritance. For almost four decades, the high-resolution structure of PrPSc, the infectious and misfolded counterpart of the cellular prion protein (PrPC), has remained elusive, mostly due to technical challenges posed by its high insolubility and aggregation propensity. As a result, such a lack of information has critically hampered the search for an effective therapy against prion diseases. Nevertheless, multiple attempts to get insights into the structure of PrPSc have provided important experimental constraints that, despite being at limited resolution, are paving the way for the application of computer-aided technologies to model the three-dimensional architecture of prions and their templated replication mechanism. Here, we review the most relevant studies carried out so far to elucidate the conformation of infectious PrPSc and offer an overview of the most advanced molecular models to explain prion structure and conversion.
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Affiliation(s)
- Giovanni Spagnolli
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, TN, Italy; Dulbecco Telethon Institute, University of Trento, Trento, TN, Italy
| | - Jesús R Requena
- CIMUS Biomedical Research Institute & Department of Medical Sciences, University of Santiago de Compostela-IDIS, Santiago, Spain
| | - Emiliano Biasini
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, TN, Italy; Dulbecco Telethon Institute, University of Trento, Trento, TN, Italy.
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11
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Caughey B, Kraus A. Transmissibility versus Pathogenicity of Self-Propagating Protein Aggregates. Viruses 2019; 11:E1044. [PMID: 31717531 PMCID: PMC6893620 DOI: 10.3390/v11111044] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 12/22/2022] Open
Abstract
The prion-like spreading and accumulation of specific protein aggregates appear to be central to the pathogenesis of many human diseases, including Alzheimer's and Parkinson's. Accumulating evidence indicates that inoculation of tissue extracts from diseased individuals into suitable experimental animals can in many cases induce the aggregation of the disease-associated protein, as well as related pathological lesions. These findings, together with the history of the prion field, have raised the questions about whether such disease-associated protein aggregates are transmissible between humans by casual or iatrogenic routes, and, if so, do they propagate enough in the new host to cause disease? These practical considerations are important because real, and perhaps even only imagined, risks of human-to-human transmission of diseases such as Alzheimer's and Parkinson's may force costly changes in clinical practice that, in turn, are likely to have unintended consequences. The prion field has taught us that a single protein, PrP, can aggregate into forms that can propagate exponentially in vitro, but range from being innocuous to deadly when injected into experimental animals in ways that depend strongly on factors such as conformational subtleties, routes of inoculation, and host responses. In assessing the hazards posed by various disease-associated, self-propagating protein aggregates, it is imperative to consider both their actual transmissibilities and the pathological consequences of their propagation, if any, in recipient hosts.
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Affiliation(s)
- Byron Caughey
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Allison Kraus
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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12
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Eraña H, Charco JM, Di Bari MA, Díaz-Domínguez CM, López-Moreno R, Vidal E, González-Miranda E, Pérez-Castro MA, García-Martínez S, Bravo S, Fernández-Borges N, Geijo M, D’Agostino C, Garrido J, Bian J, König A, Uluca-Yazgi B, Sabate R, Khaychuk V, Vanni I, Telling GC, Heise H, Nonno R, Requena JR, Castilla J. Development of a new largely scalable in vitro prion propagation method for the production of infectious recombinant prions for high resolution structural studies. PLoS Pathog 2019; 15:e1008117. [PMID: 31644574 PMCID: PMC6827918 DOI: 10.1371/journal.ppat.1008117] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 11/04/2019] [Accepted: 10/01/2019] [Indexed: 12/12/2022] Open
Abstract
The resolution of the three-dimensional structure of infectious prions at the atomic level is pivotal to understand the pathobiology of Transmissible Spongiform Encephalopathies (TSE), but has been long hindered due to certain particularities of these proteinaceous pathogens. Difficulties related to their purification from brain homogenates of disease-affected animals were resolved almost a decade ago by the development of in vitro recombinant prion propagation systems giving rise to highly infectious recombinant prions. However, lack of knowledge about the molecular mechanisms of the misfolding event and the complexity of systems such as the Protein Misfolding Cyclic Amplification (PMCA), have limited generating the large amounts of homogeneous recombinant prion preparations required for high-resolution techniques such as solid state Nuclear Magnetic Resonance (ssNMR) imaging. Herein, we present a novel recombinant prion propagation system based on PMCA that substitutes sonication with shaking thereby allowing the production of unprecedented amounts of multi-labeled, infectious recombinant prions. The use of specific cofactors, such as dextran sulfate, limit the structural heterogeneity of the in vitro propagated prions and makes possible, for the first time, the generation of infectious and likely homogeneous samples in sufficient quantities for studies with high-resolution structural techniques as demonstrated by the preliminary ssNMR spectrum presented here. Overall, we consider that this new method named Protein Misfolding Shaking Amplification (PMSA), opens new avenues to finally elucidate the three-dimensional structure of infectious prions.
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Affiliation(s)
- Hasier Eraña
- CIC bioGUNE, Derio (Bizkaia), Spain
- ATLAS Molecular Pharma S. L. Derio (Bizkaia), Spain
| | | | - Michele A. Di Bari
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | | | | | - Enric Vidal
- Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Barcelona, Spain
| | | | | | | | - Susana Bravo
- Proteomics Lab, IDIS, Santiago de Compostela, Spain
| | | | - Mariví Geijo
- Animal Health Department, NEIKER-Instituto Vasco de Investigación y Desarrollo Agrario, Derio (Bizkaia), Spain
| | - Claudia D’Agostino
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Joseba Garrido
- Animal Health Department, NEIKER-Instituto Vasco de Investigación y Desarrollo Agrario, Derio (Bizkaia), Spain
| | - Jifeng Bian
- Prion Research Center (PRC), Colorado State University, Fort Collins, Colorado, United States of America
| | - Anna König
- Institute of Complex Systems (ICS-6) and Jülich Center for Structural Biology (JuStruct), Forschungszentrum Jülich, Jülich, Germany
- Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Boran Uluca-Yazgi
- Institute of Complex Systems (ICS-6) and Jülich Center for Structural Biology (JuStruct), Forschungszentrum Jülich, Jülich, Germany
- Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Raimon Sabate
- Department of Pharmacy and Pharmaceutical Technology and Physical-Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, Spain
| | - Vadim Khaychuk
- Prion Research Center (PRC), Colorado State University, Fort Collins, Colorado, United States of America
| | - Ilaria Vanni
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Glenn C. Telling
- Prion Research Center (PRC), Colorado State University, Fort Collins, Colorado, United States of America
| | - Henrike Heise
- Institute of Complex Systems (ICS-6) and Jülich Center for Structural Biology (JuStruct), Forschungszentrum Jülich, Jülich, Germany
- Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Romolo Nonno
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Jesús R. Requena
- CIMUS Biomedical Research Institute, University of Santiago de Compostela-IDIS, Spain
| | - Joaquín Castilla
- CIC bioGUNE, Derio (Bizkaia), Spain
- IKERBasque, Basque Foundation for Science, Bilbao (Bizkaia), Spain
- * E-mail:
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13
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Shen HCH, Chen YH, Lin YS, Chu BKY, Liang CS, Yang CC, Chen RPY. Segments in the Amyloid Core that Distinguish Hamster from Mouse Prion Fibrils. Neurochem Res 2019; 44:1399-1409. [PMID: 30603982 DOI: 10.1007/s11064-018-02709-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/29/2018] [Accepted: 12/23/2018] [Indexed: 10/27/2022]
Abstract
Prion diseases are transmissible fatal neurodegenerative disorders affecting humans and other mammals. The disease transmission can occur between different species but is limited by the sequence homology between host and inoculum. The crucial molecular event in the progression of this disease is prion formation, starting from the conformational conversion of the normal, membrane-anchored prion protein (PrPC) into the misfolded, β-sheet-rich and aggregation-prone isoform (PrPSc), which then self-associates into the infectious amyloid form called prion. Amyloid is the aggregate formed from one-dimensional protein association. As amyloid formation is a key hallmark in prion pathogenesis, studying which segments in prion protein are involved in the amyloid formation can provide molecular details in the cross-species transmission barrier of prion diseases. However, due to the difficulties of studying protein aggregates, very limited knowledge about prion structure or prion formation was disclosed by now. In this study, cross-seeding assay was used to identify the segments involved in the amyloid fibril formation of full-length hamster prion protein, SHaPrP(23-231). Our results showed that the residues in the segments 108-127, 172-194 (helix 2 in PrPC) and 200-227 (helix 3 in PrPC) are in the amyloid core of hamster prion fibrils. The segment 127-143, but not 107-126 (which corresponds to hamster sequence 108-127), was previously reported to be involved in the amyloid core of full-length mouse prion fibrils. Our results indicate that hamster prion protein and mouse prion protein use different segments to form the amyloid core in amyloidogenesis. The sequence-dependent core formation can be used to explain the seeding barrier between mouse and hamster.
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Affiliation(s)
- Howard C-H Shen
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei, 11529, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan
| | - Yung-Han Chen
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei, 11529, Taiwan
| | - Yu-Sheng Lin
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei, 11529, Taiwan.,Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Brett K-Y Chu
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei, 11529, Taiwan.,Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Ching-Shin Liang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Chien-Chih Yang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Rita P-Y Chen
- Institute of Biological Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Rd, Nankang, Taipei, 11529, Taiwan. .,Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan.
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14
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A Metastable Contact and Structural Disorder in the Estrogen Receptor Transactivation Domain. Structure 2018; 27:229-240.e4. [PMID: 30581045 DOI: 10.1016/j.str.2018.10.026] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/06/2018] [Accepted: 10/25/2018] [Indexed: 11/23/2022]
Abstract
The N-terminal transactivation domain (NTD) of estrogen receptor alpha, a well-known member of the family of intrinsically disordered proteins, mediates the receptor's transactivation function. However, an accurate molecular dissection of NTD's structure-function relationships remains elusive. Here, we show that the NTD adopts a mostly disordered, unexpectedly compact conformation that undergoes structural expansion on chemical denaturation. By combining small-angle X-ray scattering, hydroxyl radical protein footprinting, and computational modeling, we derive the ensemble-structures of the NTD and determine its ensemble-contact map revealing metastable long-range contacts, e.g., between residues I33 and S118. We show that mutation at S118, a known phosphorylation site, promotes conformational changes and increases coactivator binding. We further demonstrate via fluorine-19 (19F) nuclear magnetic resonance that mutations near I33 alter 19F chemical shifts at S118, confirming the proposed I33-S118 contact in the ensemble of structural disorder. These findings extend our understanding of how specific contact metastability mediates critical functions of disordered proteins.
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15
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Li Q, Wang F, Xiao X, Kim C, Bohon J, Kiselar J, Safar JG, Ma J, Surewicz WK. Structural attributes of mammalian prion infectivity: Insights from studies with synthetic prions. J Biol Chem 2018; 293:18494-18503. [PMID: 30275016 DOI: 10.1074/jbc.ra118.005622] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 09/25/2018] [Indexed: 12/30/2022] Open
Abstract
Prion diseases are neurodegenerative disorders that affect many mammalian species. Mammalian prion proteins (PrPs) can misfold into many different aggregates. However, only a small subpopulation of these structures is infectious. One of the major unresolved questions in prion research is identifying which specific structural features of these misfolded protein aggregates are important for prion infectivity in vivo Previously, two types of proteinase K-resistant, self-propagating aggregates were generated from the recombinant mouse prion protein in the presence of identical cofactors. Although these two aggregates appear biochemically very similar, they have dramatically different biological properties, with one of them being highly infectious and the other one lacking any infectivity. Here, we used several MS-based structural methods, including hydrogen-deuterium exchange and hydroxyl radical footprinting, to gain insight into the nature of structural differences between these two PrP aggregate types. Our experiments revealed a number of specific differences in the structure of infectious and noninfectious aggregates, both at the level of the polypeptide backbone and quaternary packing arrangement. In particular, we observed that a high degree of order and stability of β-sheet structure within the entire region between residues ∼89 and 227 is a primary attribute of infectious PrP aggregates examined in this study. By contrast, noninfectious PrP aggregates are characterized by markedly less ordered structure up to residue ∼167. The structural constraints reported here should facilitate development of experimentally based high-resolution structural models of infectiosus mammalian prions.
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Affiliation(s)
- Qiuye Li
- From the Departments of Physiology and Biophysics and
| | - Fei Wang
- the Center for Neurodegenerative Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Xiangzhu Xiao
- From the Departments of Physiology and Biophysics and
| | | | - Jen Bohon
- Centers for Synchrotron Biosciences and.,Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio 44106 and
| | - Janna Kiselar
- Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio 44106 and
| | | | - Jiyan Ma
- the Center for Neurodegenerative Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503
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16
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Abstract
The cellular prion protein, PrPC, is a small, cell surface glycoprotein with a function that is currently somewhat ill defined. It is also the key molecule involved in the family of neurodegenerative disorders called transmissible spongiform encephalopathies, which are also known as prion diseases. The misfolding of PrPC to a conformationally altered isoform, designated PrPTSE, is the main molecular process involved in pathogenesis and appears to precede many other pathologic and clinical manifestations of disease, including neuronal loss, astrogliosis, and cognitive loss. PrPTSE is also believed to be the major component of the infectious "prion," the agent responsible for disease transmission, and preparations of this protein can cause prion disease when inoculated into a naïve host. Thus, understanding the biochemical and biophysical properties of both PrPC and PrPTSE, and ultimately the mechanisms of their interconversion, is critical if we are to understand prion disease biology. Although entire books could be devoted to research pertaining to the protein, herein we briefly review the state of knowledge of prion biochemistry, including consideration of prion protein structure, function, misfolding, and dysfunction.
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Affiliation(s)
- Andrew C Gill
- School of Chemistry, Joseph Banks Laboratories, University of Lincoln, Lincoln, United Kingdom; Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom.
| | - Andrew R Castle
- Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
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17
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Kim C, Xiao X, Chen S, Haldiman T, Smirnovas V, Kofskey D, Warren M, Surewicz K, Maurer NR, Kong Q, Surewicz W, Safar JG. Artificial strain of human prions created in vitro. Nat Commun 2018; 9:2166. [PMID: 29867164 PMCID: PMC5986862 DOI: 10.1038/s41467-018-04584-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/02/2018] [Indexed: 11/18/2022] Open
Abstract
The molecular mechanism that determines under physiological conditions transmissibility of the most common human prion disease, sporadic Creutzfeldt-Jakob disease (sCJD) is unknown. We report the synthesis of new human prion from the recombinant human prion protein expressed in bacteria in reaction seeded with sCJD MM1 prions and cofactor, ganglioside GM1. These synthetic human prions were infectious to transgenic mice expressing non-glycosylated human prion protein, causing neurologic dysfunction after 459 and 224 days in the first and second passage, respectively. The neuropathology, replication potency, and biophysical profiling suggest that a novel, particularly neurotoxic human prion strain was created. Distinct biological and structural characteristics of our synthetic human prions suggest that subtle changes in the structural organization of critical domains, some linked to posttranslational modifications of the pathogenic prion protein (PrPSc), play a crucial role as a determinant of human prion infectivity, host range, and targetting of specific brain structures in mice models.
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Affiliation(s)
- Chae Kim
- Department of Pathology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Xiangzhu Xiao
- Departments of Physiology and Biophysics, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Shugui Chen
- Departments of Physiology and Biophysics, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
- GlaxoSmithKline, 709 Swedeland Rd., King of Prussia, PA19406, UK
| | - Tracy Haldiman
- Department of Pathology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Vitautas Smirnovas
- Departments of Physiology and Biophysics, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
- Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Vilnius University, Graiciuno 8, Vilnius, 02241, Lithuania
| | - Diane Kofskey
- Department of Pathology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Miriam Warren
- Department of Pathology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Krystyna Surewicz
- Departments of Physiology and Biophysics, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Nicholas R Maurer
- Department of Pathology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Qingzhong Kong
- Department of Pathology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
- Department of Neurology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Witold Surewicz
- Department of Pathology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
- Departments of Physiology and Biophysics, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Jiri G Safar
- Department of Pathology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA.
- Department of Neurology, Case Western Reserve University, 2085 Adelbert Rd, Cleveland, OH, 44106, USA.
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18
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Sangeetham SB, Huszár K, Bencsura P, Nyeste A, Hunyadi-Gulyás É, Fodor E, Welker E. Interrogating the Dimerization Interface of the Prion Protein Via Site-Specific Mutations to p-Benzoyl-L-Phenylalanine. J Mol Biol 2018; 430:2784-2801. [PMID: 29778603 DOI: 10.1016/j.jmb.2018.05.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 05/07/2018] [Accepted: 05/14/2018] [Indexed: 01/10/2023]
Abstract
Transmissible spongiform encephalopathies are centered on the conformational transition of the prion protein from a mainly helical, monomeric structure to a β-sheet rich ordered aggregate. Experiments indicate that the main infectious and toxic species in this process are however shorter oligomers, formation of which from the monomers is yet enigmatic. Here, we created 25 variants of the mouse prion protein site-specifically containing one genetically-incorporated para-benzoyl-phenylalanine (pBpa), a cross-linkable non-natural amino acid, in order to interrogate the interface of a prion protein-dimer, which might lie on the pathway of oligomerization. Our results reveal that the N-terminal part of the prion protein, especially regions around position 127 and 107, is integral part of the dimer interface. These together with additional pBpa-containing variants of mPrP might also facilitate to gain more structural insights into oligomeric and fibrillar prion protein species including the pathological variants.
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Affiliation(s)
- Sudheer Babu Sangeetham
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Krisztina Huszár
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Petra Bencsura
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Antal Nyeste
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; ProteoScientia Ltd., Cserhátszentiván, Hungary
| | - Éva Hunyadi-Gulyás
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Elfrieda Fodor
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Ervin Welker
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
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19
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Abstract
Transmissible spongiform encephalopathies (TSEs) are fatal neurological disorders caused by prions, which are composed of a misfolded protein (PrPSc) that self-propagates in the brain of infected individuals by converting the normal prion protein (PrPC) into the pathological isoform. Here, we report a novel experimental strategy for preventing prion disease based on producing a self-replicating, but innocuous PrPSc-like form, termed anti-prion, which can compete with the replication of pathogenic prions. Our results show that a prophylactic inoculation of prion-infected animals with an anti-prion delays the onset of the disease and in some animals completely prevents the development of clinical symptoms and brain damage. The data indicate that a single injection of the anti-prion eliminated ~99% of the infectivity associated to pathogenic prions. Furthermore, this treatment caused significant changes in the profile of regional PrPSc deposition in the brains of animals that were treated, but still succumbed to the disease. Our findings provide new insights for a mechanistic understanding of prion replication and support the concept that prion replication can be separated from toxicity, providing a novel target for therapeutic intervention.
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20
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Honda R, Kuwata K. Evidence for a central role of PrP helix 2 in the nucleation of amyloid fibrils. FASEB J 2018; 32:3641-3652. [PMID: 29401635 DOI: 10.1096/fj.201701183rr] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Amyloid fibrils are filamentous protein aggregates associated with the pathogenesis of a wide variety of human diseases. The formation of such aggregates typically follows nucleation-dependent kinetics, wherein the assembly and structural conversion of amyloidogenic proteins into oligomeric aggregates (nuclei) is the rate-limiting step of the overall reaction. In this study, we sought to gain structural insights into the oligomeric nuclei of the human prion protein (PrP) by preparing a series of deletion mutants lacking 14-44 of the C-terminal 107 residues of PrP and examined the kinetics and thermodynamics of these mutants in amyloid formation. An analysis of the experimental data using the concepts of the Φ-value analysis indicated that the helix 2 region (residues 168-196) acquires an amyloid-like β-sheet during nucleation, whereas the other regions preserves a relatively disordered structure in the nuclei. This finding suggests that the helix 2 region serves as the nucleation site for the assembly of amyloid fibrils.-Honda, R., Kuwata, K. Evidence for a central role of PrP helix 2 in the nucleation of amyloid fibrils.
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Affiliation(s)
- Ryo Honda
- Department of Molecular Pathobiochemistry, Graduate School of Medicine, Gifu University, Gifu, Japan.,United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
| | - Kazuo Kuwata
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan.,Department of Gene and Development, Graduate School of Medicine, Gifu University, Gifu, Japan
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21
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Sevillano AM, Fernández-Borges N, Younas N, Wang F, R. Elezgarai S, Bravo S, Vázquez-Fernández E, Rosa I, Eraña H, Gil D, Veiga S, Vidal E, Erickson-Beltran ML, Guitián E, Silva CJ, Nonno R, Ma J, Castilla J, R. Requena J. Recombinant PrPSc shares structural features with brain-derived PrPSc: Insights from limited proteolysis. PLoS Pathog 2018; 14:e1006797. [PMID: 29385212 PMCID: PMC5809102 DOI: 10.1371/journal.ppat.1006797] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 02/12/2018] [Accepted: 12/08/2017] [Indexed: 11/18/2022] Open
Abstract
Very solid evidence suggests that the core of full length PrPSc is a 4-rung β-solenoid, and that individual PrPSc subunits stack to form amyloid fibers. We recently used limited proteolysis to map the β-strands and connecting loops that make up the PrPSc solenoid. Using high resolution SDS-PAGE followed by epitope analysis, and mass spectrometry, we identified positions ~116/118, 133-134, 141, 152-153, 162, 169 and 179 (murine numbering) as Proteinase K (PK) cleavage sites in PrPSc. Such sites likely define loops and/or borders of β-strands, helping us to predict the threading of the β-solenoid. We have now extended this approach to recombinant PrPSc (recPrPSc). The term recPrPSc refers to bona fide recombinant prions prepared by PMCA, exhibiting infectivity with attack rates of ~100%. Limited proteolysis of mouse and bank vole recPrPSc species yielded N-terminally truncated PK-resistant fragments similar to those seen in brain-derived PrPSc, albeit with varying relative yields. Along with these fragments, doubly N- and C-terminally truncated fragments, in particular ~89/97-152, were detected in some recPrPSc preparations; similar fragments are characteristic of atypical strains of brain-derived PrPSc. Our results suggest a shared architecture of recPrPSc and brain PrPSc prions. The observed differences, in particular the distinct yields of specific PK-resistant fragments, are likely due to differences in threading which result in the specific biochemical characteristics of recPrPSc. Furthermore, recombinant PrPSc offers exciting opportunities for structural studies unachievable with brain-derived PrPSc.
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Affiliation(s)
- Alejandro M. Sevillano
- CIMUS Biomedical Research Institute and Department of Medical Sciences University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
- * E-mail: (AMS); (JRR)
| | | | - Neelam Younas
- CIMUS Biomedical Research Institute and Department of Medical Sciences University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
| | - Fei Wang
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | | | - Susana Bravo
- Proteomics Lab, IDIS, Santiago de Compostela, Spain
| | | | - Isaac Rosa
- CIMUS Biomedical Research Institute and Department of Medical Sciences University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
| | | | | | - Sonia Veiga
- CIMUS Biomedical Research Institute and Department of Medical Sciences University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
| | - Enric Vidal
- Priocat Laboratory, Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Barcelona, Catalonia, Spain
| | | | - Esteban Guitián
- Mass spectrometry Core Facility, RIAIDT, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Christopher J. Silva
- USDA, ARS Western Regional Research Center, Albany, California, United States of America
| | - Romolo Nonno
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Jiyan Ma
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | | | - Jesús R. Requena
- CIMUS Biomedical Research Institute and Department of Medical Sciences University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
- * E-mail: (AMS); (JRR)
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22
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Role of the central lysine cluster and scrapie templating in the transmissibility of synthetic prion protein aggregates. PLoS Pathog 2017; 13:e1006623. [PMID: 28910420 PMCID: PMC5614645 DOI: 10.1371/journal.ppat.1006623] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/26/2017] [Accepted: 09/01/2017] [Indexed: 12/19/2022] Open
Abstract
Mammalian prion structures and replication mechanisms are poorly understood. Most synthetic recombinant prion protein (rPrP) amyloids prepared without cofactors are non-infectious or much less infectious than bona fide tissue-derived PrPSc. This effect has been associated with differences in folding of the aggregates, manifested in part by reduced solvent exclusion and protease-resistance in rPrP amyloids, especially within residues ~90-160. Substitution of 4 lysines within residues 101-110 of rPrP (central lysine cluster) with alanines (K4A) or asparagines (K4N) allows formation of aggregates with extended proteinase K (PK) resistant cores reminiscent of PrPSc, particularly when seeded with PrPSc. Here we have compared the infectivity of rPrP aggregates made with K4N, K4A or wild-type (WT) rPrP, after seeding with scrapie brain homogenate (ScBH) or normal brain homogenate (NBH). None of these preparations caused clinical disease on first passage into rodents. However, the ScBH-seeded fibrils (only) led to a subclinical pathogenesis as indicated by increases in prion seeding activity, neuropathology, and abnormal PrP in the brain. Seeding activities usually accumulated to much higher levels in animals inoculated with ScBH-seeded fibrils made with the K4N, rather than WT, rPrP molecules. Brain homogenates from subclinical animals induced clinical disease on second passage into "hamsterized" Tg7 mice, with shorter incubation times in animals inoculated with ScBH-seeded K4N rPrP fibrils. On second passage from animals inoculated with ScBH-seeded WT fibrils, we detected an additional PK resistant PrP fragment that was similar to that of bona fide PrPSc. Together these data indicate that both the central lysine cluster and scrapie seeding of rPrP aggregates influence the induction of PrP misfolding, neuropathology and clinical manifestations upon passage in vivo. We confirm that some rPrP aggregates can initiate further aggregation without typical pathogenesis in vivo. We also provide evidence that there is little, if any, biohazard associated with routine RT-QuIC assays.
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23
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Aguilar-Calvo P, Xiao X, Bett C, Eraña H, Soldau K, Castilla J, Nilsson KPR, Surewicz WK, Sigurdson CJ. Post-translational modifications in PrP expand the conformational diversity of prions in vivo. Sci Rep 2017; 7:43295. [PMID: 28272426 PMCID: PMC5341109 DOI: 10.1038/srep43295] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 01/23/2017] [Indexed: 12/02/2022] Open
Abstract
Misfolded prion protein aggregates (PrPSc) show remarkable structural diversity and are associated with highly variable disease phenotypes. Similarly, other proteins, including amyloid-β, tau, α-synuclein, and serum amyloid A, misfold into distinct conformers linked to different clinical diseases through poorly understood mechanisms. Here we use mice expressing glycophosphatidylinositol (GPI)-anchorless prion protein, PrPC, together with hydrogen-deuterium exchange coupled with mass spectrometry (HXMS) and a battery of biochemical and biophysical tools to investigate how post-translational modifications impact the aggregated prion protein properties and disease phenotype. Four GPI-anchorless prion strains caused a nearly identical clinical and pathological disease phenotype, yet maintained their structural diversity in the anchorless state. HXMS studies revealed that GPI-anchorless PrPSc is characterized by substantially higher protection against hydrogen/deuterium exchange in the C-terminal region near the N-glycan sites, suggesting this region had become more ordered in the anchorless state. For one strain, passage of GPI-anchorless prions into wild type mice led to the emergence of a novel strain with a unique biochemical and phenotypic signature. For the new strain, histidine hydrogen-deuterium mass spectrometry revealed altered packing arrangements of β-sheets that encompass residues 139 and 186 of PrPSc. These findings show how variation in post-translational modifications may explain the emergence of new protein conformations in vivo and also provide a basis for understanding how the misfolded protein structure impacts the disease.
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Affiliation(s)
| | - Xiangzhu Xiao
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Cyrus Bett
- Departments of Pathology and Medicine, UC San Diego, La Jolla, CA 92093-0612, USA
| | - Hasier Eraña
- CIC bioGUNE, Parque Tecnológico de Bizkaia, Ed. 800, Derio 48160, Spain
| | - Katrin Soldau
- Departments of Pathology and Medicine, UC San Diego, La Jolla, CA 92093-0612, USA
| | - Joaquin Castilla
- CIC bioGUNE, Parque Tecnológico de Bizkaia, Ed. 800, Derio 48160, Spain.,IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - K Peter R Nilsson
- Department of Physics, Chemistry, and Biology, Linköping University, Linköping 581 83, Sweden
| | - Witold K Surewicz
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Christina J Sigurdson
- Departments of Pathology and Medicine, UC San Diego, La Jolla, CA 92093-0612, USA.,Department of Pathology, Immunology, and Microbiology, UC Davis, Davis, CA 95616, USA
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24
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Stenvang M, Dueholm MS, Vad BS, Seviour T, Zeng G, Geifman-Shochat S, Søndergaard MT, Christiansen G, Meyer RL, Kjelleberg S, Nielsen PH, Otzen DE. Epigallocatechin Gallate Remodels Overexpressed Functional Amyloids in Pseudomonas aeruginosa and Increases Biofilm Susceptibility to Antibiotic Treatment. J Biol Chem 2016; 291:26540-26553. [PMID: 27784787 DOI: 10.1074/jbc.m116.739953] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 10/07/2016] [Indexed: 01/09/2023] Open
Abstract
Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea. It has antimicrobial properties and disrupts the ordered structure of amyloid fibrils involved in human disease. The antimicrobial effect of EGCG against the opportunistic pathogen Pseudomonas aeruginosa has been shown to involve disruption of quorum sensing (QS). Functional amyloid fibrils in P. aeruginosa (Fap) are able to bind and retain quorum-sensing molecules, suggesting that EGCG interferes with QS through structural remodeling of amyloid fibrils. Here we show that EGCG inhibits the ability of Fap to form fibrils; instead, EGCG stabilizes protein oligomers. Existing fibrils are remodeled by EGCG into non-amyloid aggregates. This fibril remodeling increases the binding of pyocyanin, demonstrating a mechanism by which EGCG can affect the QS function of functional amyloid. EGCG reduced the amyloid-specific fluorescent thioflavin T signal in P. aeruginosa biofilms at concentrations known to exert an antimicrobial effect. Nanoindentation studies showed that EGCG reduced the stiffness of biofilm containing Fap fibrils but not in biofilm with little Fap. In a combination treatment with EGCG and tobramycin, EGCG had a moderate effect on the minimum bactericidal eradication concentration against wild-type P. aeruginosa biofilms, whereas EGCG had a more pronounced effect when Fap was overexpressed. Our results provide a direct molecular explanation for the ability of EGCG to disrupt P. aeruginosa QS and modify its biofilm and strengthens the case for EGCG as a candidate in multidrug treatment of persistent biofilm infections.
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Affiliation(s)
- Marcel Stenvang
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN).,the Sino-Danish Centre for Education and Research (SDC), 8000 Aarhus C, Denmark
| | - Morten S Dueholm
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | - Brian S Vad
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
| | - Thomas Seviour
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | | | - Susana Geifman-Shochat
- the School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore, and
| | - Mads T Søndergaard
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | | | - Rikke Louise Meyer
- From the Interdisciplinary Nanoscience Center (iNANO).,the Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Staffan Kjelleberg
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore.,the Centre for Marine Bio-innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Mosman, New South Wales 2088, Australia
| | - Per Halkjær Nielsen
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark.,the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | - Daniel E Otzen
- From the Interdisciplinary Nanoscience Center (iNANO), .,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
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25
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Rapid α-oligomer formation mediated by the Aβ C terminus initiates an amyloid assembly pathway. Nat Commun 2016; 7:12419. [PMID: 27546208 PMCID: PMC4996947 DOI: 10.1038/ncomms12419] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 06/30/2016] [Indexed: 11/09/2022] Open
Abstract
Since early oligomeric intermediates in amyloid assembly are often transient and difficult to distinguish, characterize and quantify, the mechanistic basis of the initiation of spontaneous amyloid growth is often opaque. We describe here an approach to the analysis of the Aβ aggregation mechanism that uses Aβ-polyglutamine hybrid peptides designed to retard amyloid maturation and an adjusted thioflavin intensity scale that reveals structural features of aggregation intermediates. The results support an aggregation initiation mechanism for Aβ-polyQ hybrids, and by extension for full-length Aβ peptides, in which a modular Aβ C-terminal segment mediates rapid, non-nucleated formation of α-helical oligomers. The resulting high local concentration of tethered amyloidogenic segments within these α-oligomers facilitates transition to a β-oligomer population that, via further remodelling and/or elongation steps, ultimately generates mature amyloid. Consistent with this mechanism, an engineered Aβ C-terminal fragment delays aggregation onset by Aβ-polyglutamine peptides and redirects assembly of Aβ42 fibrils. The elucidation of amyloid nucleation mechanisms remains challenging as early oligomeric intermediates are transient and difficult to distinguish. Here the authors use Aβ- polyglutamine hybrid peptides designed to slow and limit amyloid maturation to provide insights into the structures of Aβ self-assembly intermediates.
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26
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Quanico J, Franck J, Salzet M, Fournier I. On-tissue Direct Monitoring of Global Hydrogen/Deuterium Exchange by MALDI Mass Spectrometry: Tissue Deuterium Exchange Mass Spectrometry (TDXMS). Mol Cell Proteomics 2016; 15:3321-3330. [PMID: 27512083 DOI: 10.1074/mcp.o116.059832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Indexed: 11/06/2022] Open
Abstract
Hydrogen/deuterium exchange mass spectrometric (H/DXMS) methods for protein structural analysis are conventionally performed in solution. We present Tissue Deuterium Exchange Mass Spectrometry (TDXMS), a method to directly monitor deuterium uptake on tissue, as a means to better approximate the deuterium exchange behavior of proteins in their native microenvironment. Using this method, a difference in deuterium uptake behavior was observed when the same proteins were monitored in solution and on tissue. The higher maximum deuterium uptake at equilibrium for all proteins analyzed in solution suggests a more open conformation in the absence of interacting partners normally observed on tissue. We also demonstrate a difference in the deuterium uptake behavior of a few proteins across different morphological regions of the same tissue section. Modifications of the total number of hydrogens exchanged, as well as the kinetics of exchange, were both observed. These results provide information on the implication of protein interactions with partners as well as on the conformational changes related to these interactions, and illustrate the importance of examining protein deuterium exchange behavior in the presence of its specific microenvironment directly at the level of tissues.
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Affiliation(s)
- Jusal Quanico
- From the ‡Univ. Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000 Lille, France
| | - Julien Franck
- From the ‡Univ. Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000 Lille, France
| | - Michel Salzet
- From the ‡Univ. Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000 Lille, France
| | - Isabelle Fournier
- From the ‡Univ. Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, F-59000 Lille, France
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27
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Abstract
Prion diseases are a heterogeneous class of fatal neurodegenerative disorders associated with misfolding of host cellular prion protein (PrP(C)) into a pathological isoform, termed PrP(Sc). Prion diseases affect various mammals, including humans, and effective treatments are not available. Prion diseases are distinguished from other protein misfolding disorders - such as Alzheimer's or Parkinson's disease - in that they are infectious. Prion diseases occur sporadically without any known exposure to infected material, and hereditary cases resulting from rare mutations in the prion protein have also been documented. The mechanistic underpinnings of prion and other neurodegenerative disorders remain poorly understood. Various proteomics techniques have been instrumental in early PrP(Sc) detection, biomarker discovery, elucidation of PrP(Sc) structure and mapping of biochemical pathways affected by pathogenesis. Moving forward, proteomics approaches will likely become more integrated into the clinical and research settings for the rapid diagnosis and characterization of prion pathogenesis.
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Affiliation(s)
- Roger A Moore
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIH,NIAID, Hamilton, MT 59840, USA
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28
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Müller H, Brener O, Andreoletti O, Piechatzek T, Willbold D, Legname G, Heise H. Progress towards structural understanding of infectious sheep PrP-amyloid. Prion 2015; 8:344-58. [PMID: 25482596 PMCID: PMC4601355 DOI: 10.4161/19336896.2014.983754] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The still elusive structural difference of non-infectious and infectious amyloid of the mammalian prion protein (PrP) is a major pending milestone in understanding protein-mediated infectivity in neurodegenerative diseases. Preparations of PrP-amyloid proven to be infectious have never been investigated with a high-resolution technique. All available models to date have been based on low-resolution data. Here, we establish protocols for the preparation of infectious samples of full-length recombinant (rec) PrP-amyloid in NMR-sufficient amounts by spontaneous fibrillation and seeded fibril growth from brain extract. We link biological and structural data of infectious recPrP-amyloid, derived from bioassays, atomic force microscopy, and solid-state NMR spectroscopy. Our data indicate a semi-mobile N-terminus, some residues with secondary chemical shifts typical of α-helical secondary structure in the middle part between ∼115 to ∼155, and a distinct β-sheet core C-terminal of residue ∼155. These findings are not in agreement with all current models for PrP-amyloid. We also provide evidence that samples seeded from brain extract may not differ in the overall arrangement of secondary structure elements, but rather in the flexibility of protein segments outside the β-core region. Taken together, our protocols provide an essential basis for the high-resolution characterization of non-infectious and infectious PrP-amyloid in the near future.
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Affiliation(s)
- Henrik Müller
- a Institute of Complex Systems; ICS-6: Structural Biochemistry; Forschungszentrum Jülich (FZJ) ; Jülich , Germany
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29
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Daus ML. Techniques to elucidate the conformation of prions. World J Biol Chem 2015; 6:218-222. [PMID: 26322176 PMCID: PMC4549762 DOI: 10.4331/wjbc.v6.i3.218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/04/2015] [Accepted: 06/16/2015] [Indexed: 02/05/2023] Open
Abstract
Proteinaceous infectious particles (prions) are unique pathogens as they are devoid of any coding nucleic acid. Whilst it is assumed that prion disease is transmitted by a misfolded isoform of the cellular prion protein, the structural insight of prions is still vague and research for high resolution structural information of prions is still ongoing. In this review, techniques that may contribute to the clarification of the conformation of prions are presented and discussed.
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30
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Sneideris T, Milto K, Smirnovas V. Polymorphism of amyloid-like fibrils can be defined by the concentration of seeds. PeerJ 2015; 3:e1207. [PMID: 26355941 PMCID: PMC4563235 DOI: 10.7717/peerj.1207] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/01/2015] [Indexed: 12/11/2022] Open
Abstract
Prions are infectious proteins where the same protein may express distinct strains. The strains are enciphered by different misfolded conformations. Strain-like phenomena have also been reported in a number of other amyloid-forming proteins. One of the features of amyloid strains is the ability to self-propagate, maintaining a constant set of physical properties despite being propagated under conditions different from those that allowed initial formation of the strain. Here we report a cross-seeding experiment using strains formed under different conditions. Using high concentrations of seeds results in rapid elongation and new fibrils preserve the properties of the seeding fibrils. At low seed concentrations, secondary nucleation plays the major role and new fibrils gain properties predicted by the environment rather than the structure of the seeds. Our findings could explain conformational switching between amyloid strains observed in a wide variety of in vivo and in vitro experiments.
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Affiliation(s)
- Tomas Sneideris
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | - Katažyna Milto
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | - Vytautas Smirnovas
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
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31
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Kraus A, Anson KJ, Raymond LD, Martens C, Groveman BR, Dorward DW, Caughey B. Prion Protein Prolines 102 and 105 and the Surrounding Lysine Cluster Impede Amyloid Formation. J Biol Chem 2015; 290:21510-22. [PMID: 26175152 DOI: 10.1074/jbc.m115.665844] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Indexed: 11/06/2022] Open
Abstract
Human prion diseases can have acquired, sporadic, or genetic origins, each of which results in the conversion of prion protein (PrP) to transmissible, pathological forms. The genetic prion disease Gerstmann-Straussler-Scheinker syndrome can arise from point mutations of prolines 102 or 105. However, the structural effects of these two prolines, and mutations thereof, on PrP misfolding are not well understood. Here, we provide evidence that individual mutations of Pro-102 or Pro-105 to noncyclic aliphatic residues such as the Gerstmann-Straussler-Scheinker-linked leucines can promote the in vitro formation of PrP amyloid with extended protease-resistant cores reminiscent of infectious prions. This effect was enhanced by additional charge-neutralizing mutations of four nearby lysine residues comprising the so-called central lysine cluster. Substitution of these proline and lysine residues accelerated PrP conversion such that spontaneous amyloid formation was no longer slower than scrapie-seeded amyloid formation. Thus, Pro-102 and Pro-105, as well as the lysines in the central lysine cluster, impede amyloid formation by PrP, implicating these residues as key structural modulators in the conversion of PrP to disease-associated types of amyloid.
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Affiliation(s)
- Allison Kraus
- From the Laboratory of Persistent Viral Diseases and
| | | | | | - Craig Martens
- Research Technologies Branch, Rocky Mountain Laboratories, NIAID, National Institutes of Health, Hamilton, Montana 59840
| | | | - David W Dorward
- Research Technologies Branch, Rocky Mountain Laboratories, NIAID, National Institutes of Health, Hamilton, Montana 59840
| | - Byron Caughey
- From the Laboratory of Persistent Viral Diseases and
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32
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Noble GP, Wang DW, Walsh DJ, Barone JR, Miller MB, Nishina KA, Li S, Supattapone S. A Structural and Functional Comparison Between Infectious and Non-Infectious Autocatalytic Recombinant PrP Conformers. PLoS Pathog 2015; 11:e1005017. [PMID: 26125623 PMCID: PMC4488359 DOI: 10.1371/journal.ppat.1005017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/09/2015] [Indexed: 11/30/2022] Open
Abstract
Infectious prions contain a self-propagating, misfolded conformer of the prion protein termed PrPSc. A critical prediction of the protein-only hypothesis is that autocatalytic PrPSc molecules should be infectious. However, some autocatalytic recombinant PrPSc molecules have low or undetectable levels of specific infectivity in bioassays, and the essential determinants of recombinant prion infectivity remain obscure. To identify structural and functional features specifically associated with infectivity, we compared the properties of two autocatalytic recombinant PrP conformers derived from the same original template, which differ by >105-fold in specific infectivity for wild-type mice. Structurally, hydrogen/deuterium exchange mass spectrometry (DXMS) studies revealed that solvent accessibility profiles of infectious and non-infectious autocatalytic recombinant PrP conformers are remarkably similar throughout their protease-resistant cores, except for two domains encompassing residues 91-115 and 144-163. Raman spectroscopy and immunoprecipitation studies confirm that these domains adopt distinct conformations within infectious versus non-infectious autocatalytic recombinant PrP conformers. Functionally, in vitro prion propagation experiments show that the non-infectious conformer is unable to seed mouse PrPC substrates containing a glycosylphosphatidylinositol (GPI) anchor, including native PrPC. Taken together, these results indicate that having a conformation that can be specifically adopted by post-translationally modified PrPC molecules is an essential determinant of biological infectivity for recombinant prions, and suggest that this ability is associated with discrete features of PrPSc structure. A key prediction of the prion hypothesis is that autocatalytic, misfolded PrPSc molecules should be highly infectious. Various recombinant PrPSc conformers are able to self-propagate in vitro, yet paradoxically only some of these conformers possess significant levels of specific infectivity in bioassays. Here we use two closely-matched autocatalytic recombinant PrP conformers that share the same origin but differ by >105-fold in specific infectivity to study the molecular basis of prion infectivity. We show that infectious and non-infectious autocatalytic recombinant PrP conformers have subtle structural differences, and that GPI-anchored PrP substrate molecules can only adopt the infectious PrPSc conformation. We conclude that post-translational modifications of host PrPC molecules play a critical role in restricting the range of recombinant PrPSc conformers that are biologically infectious.
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Affiliation(s)
- Geoffrey P. Noble
- Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Daphne W. Wang
- Medicine and Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, California, United States of America
| | - Daniel J. Walsh
- Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Justin R. Barone
- Department of Biological Systems Engineering, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Michael B. Miller
- Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Koren A. Nishina
- Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Sheng Li
- Medicine and Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, California, United States of America
| | - Surachai Supattapone
- Departments of Biochemistry and Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- * E-mail:
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33
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C-Terminal Threonine Reduces Aβ43 Amyloidogenicity Compared with Aβ42. J Mol Biol 2015; 428:274-291. [PMID: 26122432 DOI: 10.1016/j.jmb.2015.06.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 04/19/2015] [Accepted: 06/17/2015] [Indexed: 12/21/2022]
Abstract
Aβ43, a product of the proteolysis of the amyloid precursor protein APP, is related to Aβ42 by an additional Thr residue at the C-terminus. Aβ43 is typically generated at low levels compared with the predominant Aβ42 and Aβ40 forms, but it has been suggested that this longer peptide might have an impact on amyloid-β aggregation and Alzheimer's disease that is out of proportion to its brain content. Here, we report that both Aβ42 and Aβ43 spontaneously aggregate into mature amyloid fibrils via sequential appearance of the same series of oligomeric and protofibrillar intermediates, the earliest of which appears to lack β-structure. In spite of the additional β-branched amino acid at the C-terminus, Aβ43 fibrils have fewer strong backbone H-bonds than Aβ42 fibrils, some of which are lost at the C-terminus. In contrast to previous reports, we found that Aβ43 spontaneously aggregates more slowly than Aβ42. In addition, Aβ43 fibrils are very inefficient at seeding Aβ42 amyloid formation, even though Aβ42 fibrils efficiently seed amyloid formation by Aβ43 monomers. Finally, mixtures of Aβ42 and Aβ43 aggregate more slowly than Aβ42 alone. Both in this Aβ42/Aβ43 co-aggregation reaction and in cross-seeding by Aβ42 fibrils, the structure of the Aβ43 in the product fibrils is influenced by the presence of Aβ42. The results provide new details of amyloid structure and assembly pathways, an example of structural plasticity in prion-like replication, and data showing that low levels of Aβ43 in the brain are unlikely to favorably impact the aggregation of Aβ42.
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34
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Structural determinants of phenotypic diversity and replication rate of human prions. PLoS Pathog 2015; 11:e1004832. [PMID: 25875953 PMCID: PMC4397081 DOI: 10.1371/journal.ppat.1004832] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/24/2015] [Indexed: 11/19/2022] Open
Abstract
The infectious pathogen responsible for prion diseases is the misfolded, aggregated form of the prion protein, PrPSc. In contrast to recent progress in studies of laboratory rodent-adapted prions, current understanding of the molecular basis of human prion diseases and, especially, their vast phenotypic diversity is very limited. Here, we have purified proteinase resistant PrPSc aggregates from two major phenotypes of sporadic Creutzfeldt-Jakob disease (sCJD), determined their conformational stability and replication tempo in vitro, as well as characterized structural organization using recently emerged approaches based on hydrogen/deuterium (H/D) exchange coupled with mass spectrometry. Our data clearly demonstrate that these phenotypically distant prions differ in a major way with regard to their structural organization, both at the level of the polypeptide backbone (as indicated by backbone amide H/D exchange data) as well as the quaternary packing arrangements (as indicated by H/D exchange kinetics for histidine side chains). Furthermore, these data indicate that, in contrast to previous observations on yeast and some murine prion strains, the replication rate of sCJD prions is primarily determined not by conformational stability but by specific structural features that control the growth rate of prion protein aggregates. Sporadic Creutzfeldt-Jakob disease (sCJD) represents ~90% of all human prion diseases worldwide. This neurodegenerative disease, which is transmissible and invariably fatal, is characterized by variable progression rates and remarkable diversity of clinical and pathological traits. The infectious sCJD prions propagating the pathology mainly in the brain are assemblies of abnormally folded isoform (PrPSc) of a host-encoded prion protein (PrPC). The structure and replication mechanisms of human prions are unknown, and whether the PrPSc subtypes identified by proteolytic fragmentation represent distinct strains of sCJD prions has been debated. Here, we isolated sCJD prions from patients with two very distant phenotypes of the disease, compared their structural organization using recently developed biophysical techniques, and investigated their replication in vitro. Our data indicate that these sCJD prions are characterized by different secondary structure organization and quaternary packing arrangements, and that these structural differences are responsible for distinct prion replication rates and unique phenotypic characteristics of the disease. Furthermore, our analysis reveals that, contrary to previous observations for yeast prions, the replication tempo of sCJD prions is determined not so much by their conformational stability but by specific structural features that control the growth speed of prion particles.
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35
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Silva CJ. Applying the tools of chemistry (mass spectrometry and covalent modification by small molecule reagents) to the detection of prions and the study of their structure. Prion 2015; 8:42-50. [PMID: 24509645 DOI: 10.4161/pri.27891] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Prions are molecular pathogens, able to convert a normal cellular prion protein (PrP(C)) into a prion (PrP(Sc)). The information necessary for this conversion is contained in the conformation of PrP(Sc). Mass spectrometry (MS) and small-molecule covalent reactions have been used to study prions. Mass spectrometry has been used to detect and quantitate prions in the attomole range (10⁻¹⁸ mole). MS-based analysis showed that both possess identical amino acid sequences, one disulfide bond, a GPI anchor, asparagine-linked sugar antennae, and unoxidized methionines. Mass spectrometry has been used to define elements of the secondary and tertiary structure of wild-type PrP(Sc) and GPI-anchorless PrP(Sc). It has also been used to study the quaternary structure of the PrP(Sc) multimer. Small molecule reagents react differently with the same lysine in the PrP(C) conformation than in the PrP(Sc) conformation. Such differences can be detected by Western blot using mAbs with lysine-containing epitopes, such as 3F4 and 6D11. This permits the detection of PrP(Sc) without the need for proteinase K pretreatment and can be used to distinguish among prion strains. These results illustrate how two important chemical tools, mass spectrometry and covalent modification by small molecules, are being applied to the detection and structural study of prions. Furthermore these tools are or can be applied to the study of the other protein misfolding diseases such as Alzheimer Disease, Parkinson Disease, or ALS.
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36
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Groveman BR, Kraus A, Raymond LD, Dolan MA, Anson KJ, Dorward DW, Caughey B. Charge neutralization of the central lysine cluster in prion protein (PrP) promotes PrP(Sc)-like folding of recombinant PrP amyloids. J Biol Chem 2015; 290:1119-28. [PMID: 25416779 PMCID: PMC4294479 DOI: 10.1074/jbc.m114.619627] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 11/20/2014] [Indexed: 11/06/2022] Open
Abstract
The structure of the infectious form of prion protein, PrP(Sc), remains unclear. Most pure recombinant prion protein (PrP) amyloids generated in vitro are not infectious and lack the extent of the protease-resistant core and solvent exclusion of infectious PrP(Sc), especially within residues ∼90-160. Polyanionic cofactors can enhance infectivity and PrP(Sc)-like characteristics of such fibrils, but the mechanism of this enhancement is unknown. In considering structural models of PrP(Sc) multimers, we identified an obstacle to tight packing that might be overcome with polyanionic cofactors, namely, electrostatic repulsion between four closely spaced cationic lysines within a central lysine cluster of residues 101-110. For example, in our parallel in-register intermolecular β-sheet model of PrP(Sc), not only would these lysines be clustered within the 101-110 region of the primary sequence, but they would have intermolecular spacings of only ∼4.8 Å between stacked β-strands. We have now performed molecular dynamics simulations predicting that neutralization of the charges on these lysine residues would allow more stable parallel in-register packing in this region. We also show empirically that substitution of these clustered lysine residues with alanines or asparagines results in recombinant PrP amyloid fibrils with extended proteinase-K resistant β-sheet cores and infrared spectra that are more reminiscent of bona fide PrP(Sc). These findings indicate that charge neutralization at the central lysine cluster is critical for the folding and tight packing of N-proximal residues within PrP amyloid fibrils. This charge neutralization may be a key aspect of the mechanism by which anionic cofactors promote PrP(Sc) formation.
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Affiliation(s)
| | - Allison Kraus
- From the Laboratory of Persistent Viral Diseases and
| | | | - Michael A Dolan
- the Computational Biology Section, Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | | | - David W Dorward
- the Research Technologies Branch, Microscopy Unit, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840 and
| | - Byron Caughey
- From the Laboratory of Persistent Viral Diseases and
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Salisbury JP, Liu Q, Agar JN. QUDeX-MS: hydrogen/deuterium exchange calculation for mass spectra with resolved isotopic fine structure. BMC Bioinformatics 2014; 15:403. [PMID: 25495703 PMCID: PMC4274694 DOI: 10.1186/s12859-014-0403-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 12/01/2014] [Indexed: 12/25/2022] Open
Abstract
Background Hydrogen/deuterium exchange (HDX) coupled to mass spectrometry permits analysis of structure, dynamics, and molecular interactions of proteins. HDX mass spectrometry is confounded by deuterium exchange-associated peaks overlapping with peaks of heavy, natural abundance isotopes, such as carbon-13. Recent studies demonstrated that high-performance mass spectrometers could resolve isotopic fine structure and eliminate this peak overlap, allowing direct detection and quantification of deuterium incorporation. Results Here, we present a graphical tool that allows for a rapid and automated estimation of deuterium incorporation from a spectrum with isotopic fine structure. Given a peptide sequence (or elemental formula) and charge state, the mass-to-charge ratios of deuterium-associated peaks of the specified ion is determined. Intensities of peaks in an experimental mass spectrum within bins corresponding to these values are used to determine the distribution of deuterium incorporated. A theoretical spectrum can then be calculated based on the estimated distribution of deuterium exchange to confirm interpretation of the spectrum. Deuterium incorporation can also be detected for ion signals without a priori specification of an elemental formula, permitting detection of exchange in complex samples of unidentified material such as natural organic matter. A tool is also incorporated into QUDeX-MS to help in assigning ion signals from peptides arising from enzymatic digestion of proteins. MATLAB-deployable and standalone versions are available for academic use at qudex-ms.sourceforge.net and agarlabs.com. Conclusion Isotopic fine structure HDX-MS offers the potential to increase sequence coverage of proteins being analyzed through mass accuracy and deconvolution of overlapping ion signals. As previously demonstrated, however, the data analysis workflow for HDX-MS data with resolved isotopic fine structure is distinct. QUDeX-MS we hope will aid in the adoption of isotopic fine structure HDX-MS by providing an intuitive workflow and interface for data analysis.
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Affiliation(s)
- Joseph P Salisbury
- Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences and Barnett Institute of Chemical and Biological Analysis, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA.
| | - Qian Liu
- Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences and Barnett Institute of Chemical and Biological Analysis, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA.
| | - Jeffrey N Agar
- Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences and Barnett Institute of Chemical and Biological Analysis, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA.
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Kim DH, Lee HM, Ryou C. Evaluation of infective property of recombinant prion protein amyloids in cultured cells overexpressing cellular prion protein. J Korean Med Sci 2014; 29:1604-9. [PMID: 25469058 PMCID: PMC4248579 DOI: 10.3346/jkms.2014.29.12.1604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/06/2014] [Indexed: 11/22/2022] Open
Abstract
Misfolded isoform of prion protein (PrP), termed scrapie PrP (PrP(Sc)), tends to aggregate into various fibril forms. Previously, we reported various conditions that affect aggregation of recombinant PrP into amyloids. Because amyloidogenesis of PrP is closely associated with transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, we investigated infectivity of recombinant PrP amyloids generated in vitro. Using cultured cell lines which overexpress cellular PrP of different species, we measured the level of de novo synthesized PrP(Sc) in cells inoculated with recombinant mouse PrP amyloids. While PrP-overexpressing cells were susceptible to mouse-adapted scrapie prions used as the positive control, demonstrating the species barrier effect, infection with amyloids made of truncated recombinant PrP (PrP[89-230]) failed to form and propagate PrP(Sc) even in the cells that express mouse cellular PrP. This suggests that infectivity of PrP amyloids generated in vitro is different from that of natural prions. Recombinant PrP (89-230) amyloids tested in the current study retain no or a minute level, if any, of prion infectivity.
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Affiliation(s)
- Dae-Hwan Kim
- Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Korea
| | - Hye-Mi Lee
- Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Korea
| | - Chongsuk Ryou
- Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Korea
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How does domain replacement affect fibril formation of the rabbit/human prion proteins. PLoS One 2014; 9:e113238. [PMID: 25401497 PMCID: PMC4234653 DOI: 10.1371/journal.pone.0113238] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 10/25/2014] [Indexed: 12/16/2022] Open
Abstract
Background It is known that in vivo human prion protein (PrP) have the tendency to form fibril deposits and are associated with infectious fatal prion diseases, while the rabbit PrP does not readily form fibrils and is unlikely to cause prion diseases. Although we have previously demonstrated that amyloid fibrils formed by the rabbit PrP and the human PrP have different secondary structures and macromolecular crowding has different effects on fibril formation of the rabbit/human PrPs, we do not know which domains of PrPs cause such differences. In this study, we have constructed two PrP chimeras, rabbit chimera and human chimera, and investigated how domain replacement affects fibril formation of the rabbit/human PrPs. Methodology/Principal Findings As revealed by thioflavin T binding assays and Sarkosyl-soluble SDS-PAGE, the presence of a strong crowding agent dramatically promotes fibril formation of both chimeras. As evidenced by circular dichroism, Fourier transform infrared spectroscopy, and proteinase K digestion assays, amyloid fibrils formed by human chimera have secondary structures and proteinase K-resistant features similar to those formed by the human PrP. However, amyloid fibrils formed by rabbit chimera have proteinase K-resistant features and secondary structures in crowded physiological environments different from those formed by the rabbit PrP, and secondary structures in dilute solutions similar to the rabbit PrP. The results from transmission electron microscopy show that macromolecular crowding caused human chimera but not rabbit chimera to form short fibrils and non-fibrillar particles. Conclusions/Significance We demonstrate for the first time that the domains beyond PrP-H2H3 (β-strand 1, α-helix 1, and β-strand 2) have a remarkable effect on fibrillization of the rabbit PrP but almost no effect on the human PrP. Our findings can help to explain why amyloid fibrils formed by the rabbit PrP and the human PrP have different secondary structures and why macromolecular crowding has different effects on fibrillization of PrPs from different species.
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40
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Conformational properties of prion strains can be transmitted to recombinant prion protein fibrils in real-time quaking-induced conversion. J Virol 2014; 88:11791-801. [PMID: 25078700 DOI: 10.1128/jvi.00585-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The phenomenon of prion strains with distinct biological characteristics has been hypothesized to be involved in the structural diversity of abnormal prion protein (PrP(Sc)). However, the molecular basis of the transmission of strain properties remains poorly understood. Real-time quaking-induced conversion (RT-QUIC) is a cell-free system that uses Escherichia coli-derived recombinant PrP (rPrP) for the sensitive detection of PrP(Sc). To investigate whether the properties of various prion strains can be transmitted to amyloid fibrils consisting of rPrP (rPrP fibrils) using RT-QUIC, we examined the secondary structure, conformational stability, and infectivity of rPrP fibrils seeded with PrP(Sc) derived from either the Chandler or the 22L strain. In the first round of the reaction, there were differences in the secondary structures, especially in bands attributed to β-sheets, as determined by infrared spectroscopy, and conformational stability between Chandler-seeded (1st-rPrP-fib(Ch)) and 22L-seeded (1st-rPrP-fib(22L)) rPrP fibrils. Of note, specific identifying characteristics of the two rPrP fibril types seen in the β-sheets resembled those of the original PrP(Sc). Furthermore, the conformational stability of 1st-rPrP-fib(Ch) was significantly higher than that of 1st-rPrP-fib(22L), as with Chandler and 22L PrP(Sc). The survival periods of mice inoculated with 1st-rPrP-fib(Ch) or 1st-rPrP-fib(22L) were significantly shorter than those of mice inoculated with mixtures from the mock 1st-round RT-QUIC procedure. In contrast, these biochemical characteristics were no longer evident in subsequent rounds, suggesting that nonspecific uninfected rPrP fibrils became predominant probably because of their high growth rate. Together, these findings show that at least some strain-specific conformational properties can be transmitted to rPrP fibrils and unknown cofactors or environmental conditions may be required for further conservation. Importance: The phenomenon of prion strains with distinct biological characteristics is assumed to result from the conformational variations in the abnormal prion protein (PrP(Sc)). However, important questions remain about the mechanistic relationship between the conformational differences and the strain diversity, including how strain-specific conformations are transmitted. In this study, we investigated whether the properties of diverse prion strains can be transmitted to amyloid fibrils consisting of E. coli-derived recombinant PrP (rPrP) generated by real-time quaking-induced conversion (RT-QUIC), a recently developed in vitro PrP(Sc) formation method. We demonstrate that at least some of the strain-specific conformational properties can be transmitted to rPrP fibrils in the first round of RT-QUIC by examining the secondary structure, conformational stability, and infectivity of rPrP fibrils seeded with PrP(Sc) derived from either the Chandler or the 22L prion strain. We believe that these findings will advance our understanding of the conformational basis underlying prion strain diversity.
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41
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Groveman BR, Dolan MA, Taubner LM, Kraus A, Wickner RB, Caughey B. Parallel in-register intermolecular β-sheet architectures for prion-seeded prion protein (PrP) amyloids. J Biol Chem 2014; 289:24129-42. [PMID: 25028516 DOI: 10.1074/jbc.m114.578344] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Structures of the infectious form of prion protein (e.g. PrP(Sc) or PrP-Scrapie) remain poorly defined. The prevalent structural models of PrP(Sc) retain most of the native α-helices of the normal, noninfectious prion protein, cellular prion protein (PrP(C)), but evidence is accumulating that these helices are absent in PrP(Sc) amyloid. Moreover, recombinant PrP(C) can form amyloid fibrils in vitro that have parallel in-register intermolecular β-sheet architectures in the domains originally occupied by helices 2 and 3. Here, we provide solid-state NMR evidence that the latter is also true of initially prion-seeded recombinant PrP amyloids formed in the absence of denaturants. These results, in the context of a primarily β-sheet structure, led us to build detailed models of PrP amyloid based on parallel in-register architectures, fibrillar shapes and dimensions, and other available experimentally derived conformational constraints. Molecular dynamics simulations of PrP(90-231) octameric segments suggested that such linear fibrils, which are consistent with many features of PrP(Sc) fibrils, can have stable parallel in-register β-sheet cores. These simulations revealed that the C-terminal residues ∼124-227 more readily adopt stable tightly packed structures than the N-terminal residues ∼90-123 in the absence of cofactors. Variations in the placement of turns and loops that link the β-sheets could give rise to distinct prion strains capable of faithful template-driven propagation. Moreover, our modeling suggests that single PrP monomers can comprise the entire cross-section of fibrils that have previously been assumed to be pairs of laterally associated protofilaments. Together, these insights provide a new basis for deciphering mammalian prion structures.
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Affiliation(s)
- Bradley R Groveman
- From the Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, National Institutes of Health, Hamilton, Montana 59840 and
| | - Michael A Dolan
- the Computational Biology Section, Bioinformatics and Computational Biosciences Branch, NIAID, and
| | - Lara M Taubner
- From the Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, National Institutes of Health, Hamilton, Montana 59840 and
| | - Allison Kraus
- From the Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, National Institutes of Health, Hamilton, Montana 59840 and
| | - Reed B Wickner
- Laboratory of Biochemistry and Genetics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Byron Caughey
- From the Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, National Institutes of Health, Hamilton, Montana 59840 and
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42
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Milto K, Michailova K, Smirnovas V. Elongation of mouse prion protein amyloid-like fibrils: effect of temperature and denaturant concentration. PLoS One 2014; 9:e94469. [PMID: 24747600 PMCID: PMC3991587 DOI: 10.1371/journal.pone.0094469] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 03/17/2014] [Indexed: 01/08/2023] Open
Abstract
Prion protein is known to have the ability to adopt a pathogenic conformation, which seems to be the basis for protein-only infectivity. The infectivity is based on self-replication of this pathogenic prion structure. One of possible mechanisms for such replication is the elongation of amyloid-like fibrils. We measured elongation kinetics and thermodynamics of mouse prion amyloid-like fibrils at different guanidine hydrochloride (GuHCl) concentrations. Our data show that both increases in temperature and GuHCl concentration help unfold monomeric protein and thus accelerate elongation. Once the monomers are unfolded, further increases in temperature raise the rate of elongation, whereas the addition of GuHCl decreases it. We demonstrated a possible way to determine different activation energies of amyloid-like fibril elongation by using folded and unfolded protein molecules. This approach separates thermodynamic data for fibril-assisted monomer unfolding and for refolding and formation of amyloid-like structure.
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Affiliation(s)
- Katazyna Milto
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology, Vilnius, Lithuania
| | - Ksenija Michailova
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology, Vilnius, Lithuania
| | - Vytautas Smirnovas
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology, Vilnius, Lithuania
- * E-mail:
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43
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Taguchi Y, Schätzl HM. Identifying critical sites of PrP(c)-PrP(Sc) interaction in prion-infected cells by dominant-negative inhibition. Prion 2013; 7:452-6. [PMID: 24401595 PMCID: PMC4201612 DOI: 10.4161/pri.27500] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
A direct physical interaction of the prion protein isoforms is a key element in prion conversion. Which sites interact first and which parts of PrPc are converted subsequently is presently not known in detail. We hypothesized that structural changes induced by PrPSc interaction occur in more than one interface and subsequently propagate within the PrPC substrate, like epicenters of structural changes. To identify potential interfaces we created a series of systematically-designed mutant PrPs and tested them in prion-infected cells for dominant-negative inhibition (DNI) effects. This showed that mutant PrPs with deletions in the region between first and second α-helix are involved in PrP-PrP interaction and conversion of PrPC into PrPSc. Although some PrPs did not reach the plasma membrane, they had access to the locales of prion conversion and PrPSc recycling using autophagy pathways. Using other series of mutant PrPs we already have identified additional sites which constitute potential interaction interfaces. Our approach has the potential to characterize PrP-PrP interaction sites in the context of prion-infected cells. Besides providing further insights into the molecular mechanisms of prion conversion, this data may help to further elucidate how prion strain diversity is maintained.
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Affiliation(s)
- Yuzuru Taguchi
- Department of Comparative Biology & Experimental Medicine; Faculty of Veterinary Medicine; University of Calgary; Calgary, AB Canada
| | - Hermann M Schätzl
- Department of Comparative Biology & Experimental Medicine; Faculty of Veterinary Medicine; University of Calgary; Calgary, AB Canada; Departments of Molecular Biology and of Veterinary Sciences; University of Wyoming; Laramie, Wyoming, USA
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44
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Cobb NJ, Apostol MI, Chen S, Smirnovas V, Surewicz WK. Conformational stability of mammalian prion protein amyloid fibrils is dictated by a packing polymorphism within the core region. J Biol Chem 2013; 289:2643-50. [PMID: 24338015 DOI: 10.1074/jbc.m113.520718] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mammalian prion strains are believed to arise from the propagation of distinct conformations of the misfolded prion protein PrP(Sc). One key operational parameter used to define differences between strains has been conformational stability of PrP(Sc) as defined by resistance to thermal and/or chemical denaturation. However, the structural basis of these stability differences is unknown. To bridge this gap, we have generated two strains of recombinant human prion protein amyloid fibrils that show dramatic differences in conformational stability and have characterized them by a number of biophysical methods. Backbone amide hydrogen/deuterium exchange experiments revealed that, in sharp contrast to previously studied strains of infectious amyloid formed from the yeast prion protein Sup35, differences in β-sheet core size do not underlie differences in conformational stability between strains of mammalian prion protein amyloid. Instead, these stability differences appear to be dictated by distinct packing arrangements (i.e. steric zipper interfaces) within the amyloid core, as indicated by distinct x-ray fiber diffraction patterns and large strain-dependent differences in hydrogen/deuterium exchange kinetics for histidine side chains within the core region. Although this study was limited to synthetic prion protein amyloid fibrils, a similar structural basis for strain-dependent conformational stability may apply to brain-derived PrP(Sc), especially because large strain-specific differences in PrP(Sc) stability are often observed despite a similar size of the PrP(Sc) core region.
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45
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Miller MB, Wang DW, Wang F, Noble GP, Ma J, Woods VL, Li S, Supattapone S. Cofactor molecules induce structural transformation during infectious prion formation. Structure 2013; 21:2061-8. [PMID: 24120764 DOI: 10.1016/j.str.2013.08.025] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 08/30/2013] [Accepted: 08/30/2013] [Indexed: 12/12/2022]
Abstract
The spread of misfolded proteins may occur in many neurodegenerative diseases. Mammalian prions are currently the only misfolded proteins in which high specific biological infectivity can be produced in vitro. Using a system that generates infectious prions de novo from purified recombinant PrP and conversion cofactors palmitoyl-oleoyl-phosphatidylglycerol (POPG) and RNA, we examined by deuterium exchange mass spectrometry (DXMS) the stepwise protein conformational changes that occur during prion formation. We found that initial incubation with POPG causes major structural changes in PrP involving all three α helices and one β strand, with subsequent addition of RNA rendering the N terminus highly exposed. Final conversion into the infectious PrP(Sc) form was accompanied by globally decreased solvent exposure, with persistence of the major cofactor-induced conformational features. Thus, we report that cofactor molecules appear to induce major structural rearrangements during prion formation, initiating a dynamic sequence of conformational changes resulting in biologically active prions.
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Affiliation(s)
- Michael B Miller
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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46
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Singh J, Udgaonkar JB. Dissection of Conformational Conversion Events during Prion Amyloid Fibril Formation Using Hydrogen Exchange and Mass Spectrometry. J Mol Biol 2013; 425:3510-21. [DOI: 10.1016/j.jmb.2013.06.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/10/2013] [Accepted: 06/12/2013] [Indexed: 10/26/2022]
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47
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Dutta A, Chen S, Surewicz WK. The effect of β2-α2 loop mutation on amyloidogenic properties of the prion protein. FEBS Lett 2013; 587:2918-23. [PMID: 23892077 DOI: 10.1016/j.febslet.2013.07.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/09/2013] [Accepted: 07/15/2013] [Indexed: 10/26/2022]
Abstract
Recent studies revealed that elk-like S170N/N174T mutation in mouse prion protein (moPrP), which results in an increased rigidity of β2-α2 loop, leads to a prion disease in transgenic mice. Here we characterized the effect of this mutation on biophysical properties of moPrP. Despite similar thermodynamic stabilities of wild type and mutant proteins, the latter was found to have markedly higher propensity to form amyloid fibrils. Importantly, this effect was observed even under fully denaturing conditions, indicating that the increased conversion propensity of the mutant protein is not due to loop rigidity but rather results from greater amyloidogenic potential of the amino acid sequence within the loop region of S170N/N174T moPrP.
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Affiliation(s)
- Arpana Dutta
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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48
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Kraus A, Groveman BR, Caughey B. Prions and the potential transmissibility of protein misfolding diseases. Annu Rev Microbiol 2013; 67:543-64. [PMID: 23808331 DOI: 10.1146/annurev-micro-092412-155735] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Prions, or infectious proteins, represent a major frontier in the study of infectious agents. The prions responsible for mammalian transmissible spongiform encephalopathies (TSEs) are due primarily to infectious self-propagation of misfolded prion proteins. TSE prion structures remain ill-defined, other than being highly structured, self-propagating, and often fibrillar protein multimers with the capacity to seed, or template, the conversion of their normal monomeric precursors into a pathogenic form. Purified TSE prions usually take the form of amyloid fibrils, which are self-seeding ultrastructures common to many serious protein misfolding diseases such as Alzheimer's, Parkinson's, Huntington's and Lou Gehrig's (amytrophic lateral sclerosis). Indeed, recent reports have now provided evidence of prion-like propagation of several misfolded proteins from cell to cell, if not from tissue to tissue or individual to individual. These findings raise concerns that various protein misfolding diseases might have spreading, prion-like etiologies that contribute to pathogenesis or prevalence.
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Affiliation(s)
- Allison Kraus
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840;
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49
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Taguchi Y, Mistica AMA, Kitamoto T, Schätzl HM. Critical significance of the region between Helix 1 and 2 for efficient dominant-negative inhibition by conversion-incompetent prion protein. PLoS Pathog 2013; 9:e1003466. [PMID: 23825952 PMCID: PMC3694865 DOI: 10.1371/journal.ppat.1003466] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 05/13/2013] [Indexed: 01/01/2023] Open
Abstract
Prion diseases are fatal infectious neurodegenerative disorders in man and animals associated with the accumulation of the pathogenic isoform PrPSc of the host-encoded prion protein (PrPc). A profound conformational change of PrPc underlies formation of PrPSc and prion propagation involves conversion of PrPc substrate by direct interaction with PrPSc template. Identifying the interfaces and modalities of inter-molecular interactions of PrPs will highly advance our understanding of prion propagation in particular and of prion-like mechanisms in general. To identify the region critical for inter-molecular interactions of PrP, we exploited here dominant-negative inhibition (DNI) effects of conversion-incompetent, internally-deleted PrP (ΔPrP) on co-expressed conversion-competent PrP. We created a series of ΔPrPs with different lengths of deletions in the region between first and second α-helix (H1∼H2) which was recently postulated to be of importance in prion species barrier and PrP fibril formation. As previously reported, ΔPrPs uniformly exhibited aberrant properties including detergent insolubility, limited protease digestion resistance, high-mannose type N-linked glycans, and intracellular localization. Although formerly controversial, we demonstrate here that ΔPrPs have a GPI anchor attached. Surprisingly, despite very similar biochemical and cell-biological properties, DNI efficiencies of ΔPrPs varied significantly, dependant on location and inversely correlated with the size of deletion. This data demonstrates that H1∼H2 and the region C-terminal to it are critically important for efficient DNI. It also suggests that this region is involved in PrP-PrP interaction and conversion of PrPC into PrPSc. To reconcile the paradox of how an intracellular PrP can exert DNI, we demonstrate that ΔPrPs are subject to both proteasomal and lysosomal/autophagic degradation pathways. Using autophagy pathways ΔPrPs obtain access to the locale of prion conversion and PrPSc recycling and can exert DNI there. This shows that the intracellular trafficking of PrPs is more complex than previously anticipated. Prion diseases are deadly infectious diseases of the brain characterized by accumulation of a pathologic protein (PrPSc) which is derived from the normal prion protein (PrPc). Prions replicate by direct contact in a template-directed refolding process which involves conversion of PrPC into PrPSc. Identifying the modalities of this interaction can advance our molecular understanding of prion diseases. Like substrates and competitive inhibitors of enzymes, a conversion-incompetent PrP can inhibit conversion of normal PrPC, a phenomenon known as dominant-negative inhibition (DNI). Interestingly, some conversion-incompetent PrPs efficiently cause DNI but others do not, presumably depending on affinity for PrPSc and integrity of interaction interface. We utilized DNI to characterize the PrP-PrP interaction interface in cultured cells. We created a series of PrPs with internal deletions in the region between helix 1 and 2 and evaluated their DNI. We found an inverse correlation between deletion size and DNI which suggests that this region plays an important role in PrP-PrP interaction. We also found that such PrPs are subject to various cellular degradation pathways and that a fraction of them reaches the intracellular locale of prion conversion. Further investigation of such prion proteins might help elucidating the cellular mechanisms of the PrPC-PrPSc interaction.
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Affiliation(s)
- Yuzuru Taguchi
- Departments of Veterinary Sciences and of Molecular Biology, University of Wyoming, Laramie, Wyoming, United States of America.
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50
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Bett C, Kurt TD, Lucero M, Trejo M, Rozemuller AJ, Kong Q, Nilsson KPR, Masliah E, Oldstone MB, Sigurdson CJ. Defining the conformational features of anchorless, poorly neuroinvasive prions. PLoS Pathog 2013; 9:e1003280. [PMID: 23637596 PMCID: PMC3630170 DOI: 10.1371/journal.ppat.1003280] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 02/11/2013] [Indexed: 11/19/2022] Open
Abstract
Infectious prions cause diverse clinical signs and form an extraordinary range of structures, from amorphous aggregates to fibrils. How the conformation of a prion dictates the disease phenotype remains unclear. Mice expressing GPI-anchorless or GPI-anchored prion protein exposed to the same infectious prion develop fibrillar or nonfibrillar aggregates, respectively, and show a striking divergence in the disease pathogenesis. To better understand how a prion's physical properties govern the pathogenesis, infectious anchorless prions were passaged in mice expressing anchorless prion protein and the resulting prions were biochemically characterized. Serial passage of anchorless prions led to a significant decrease in the incubation period to terminal disease and altered the biochemical properties, consistent with a transmission barrier effect. After an intraperitoneal exposure, anchorless prions were only weakly neuroinvasive, as prion plaques rarely occurred in the brain yet were abundant in extracerebral sites such as heart and adipose tissue. Anchorless prions consistently showed very high stability in chaotropes or when heated in SDS, and were highly resistant to enzyme digestion. Consistent with the results in mice, anchorless prions from a human patient were also highly stable in chaotropes. These findings reveal that anchorless prions consist of fibrillar and highly stable conformers. The additional finding from our group and others that both anchorless and anchored prion fibrils are poorly neuroinvasive strengthens the hypothesis that a fibrillar prion structure impedes efficient CNS invasion. Prions cause fatal neurodegenerative disease in humans and animals and there is currently no treatment available. The cellular prion protein is normally tethered to the outer leaflet of the plasma membrane by a glycophosphatidyl inositol (GPI) anchor. A rare stop codon mutation in the PRNP gene leads to the production of GPI-anchorless prion protein and the development of familial prion disease, which has been reproduced in mouse models. GPI-anchorless prions in humans or mice form large, dense plaques containing fibrils in the brain that vary from the more common non-fibrillar prion aggregates. Here we investigated the biochemical differences between GPI-anchored and GPI-anchorless prions. We also assessed the capacity of GPI-anchorless prions to spread from entry sites into the central nervous system. We found that infectious GPI-anchorless prions were extraordinarily stable when exposed to protein denaturing conditions. Additionally, we show that GPI-anchorless prions rarely invade the central nervous system and then only after long incubation periods, despite their presence in extraneural tissues including adipose tissue and heart. Our study shows that GPI-anchored prions converted into GPI-anchorless prions become extraordinarily stable, more resistant to enzyme digestion, and are poorly able to invade the nervous system.
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Affiliation(s)
- Cyrus Bett
- Department of Pathology, University of California, San Diego, La Jolla, California, United States of America
| | - Tim D. Kurt
- Department of Pathology, University of California, San Diego, La Jolla, California, United States of America
| | - Melanie Lucero
- Department of Pathology, University of California, San Diego, La Jolla, California, United States of America
| | - Margarita Trejo
- Department of Neuroscience, University of California, San Diego, La Jolla, California, United States of America
| | - Annemieke J. Rozemuller
- Dutch Surveillance Centre for Prion Diseases, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Qingzhong Kong
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - K. Peter R. Nilsson
- Department of Chemistry, Biology, and Physics, Linkoping University, Linkoping, Sweden
| | - Eliezer Masliah
- Department of Neuroscience, University of California, San Diego, La Jolla, California, United States of America
| | - Michael B. Oldstone
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Christina J. Sigurdson
- Department of Pathology, University of California, San Diego, La Jolla, California, United States of America
- Department of Pathology, Immunology, and Microbiology, University of California, Davis, Davis, California, United States of America
- * E-mail:
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