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Shoup D, Priola SA. Grp78 destabilization of infectious prions is strain-specific and modified by multiple factors including accessory chaperones and pH. J Biol Chem 2024; 300:107346. [PMID: 38718859 PMCID: PMC11176782 DOI: 10.1016/j.jbc.2024.107346] [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: 12/18/2023] [Revised: 04/01/2024] [Accepted: 04/22/2024] [Indexed: 06/03/2024] Open
Abstract
Lethal neurodegenerative prion diseases result from the continuous accumulation of infectious and variably protease-resistant prion protein aggregates (PrPD) which are misfolded forms of the normally detergent soluble and protease-sensitive cellular prion protein. Molecular chaperones like Grp78 have been found to reduce the accumulation of PrPD, but how different cellular environments and other chaperones influence the ability of Grp78 to modify PrPD is poorly understood. In this work, we investigated how pH and protease-mediated structural changes in PrPD from two mouse-adapted scrapie prion strains, 22L and 87V, influenced processing by Grp78 in the presence or absence of chaperones Hsp90, DnaJC1, and Stip1. We developed a cell-free in vitro system to monitor chaperone-mediated structural changes to, and disaggregation of, PrPD. For both strains, Grp78 was most effective at structurally altering PrPD at low pH, especially when additional chaperones were present. While Grp78, DnaJC1, Stip1, and Hsp90 were unable to disaggregate the majority of PrPD from either strain, pretreatment of PrPD with proteases increased disaggregation of 22L PrPD compared to 87V, indicating strain-specific differences in aggregate structure were impacting chaperone activity. Hsp90 also induced structural changes in 87V PrPD as indicated by an increase in the susceptibility of its n-terminus to proteases. Our data suggest that, while chaperones like Grp78, DnaJC1, Stip1, and Hsp90 disaggregate only a small fraction of PrPD, they may still facilitate its clearance by altering aggregate structure and sensitizing PrPD to proteases in a strain and pH-dependent manner.
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Affiliation(s)
- Daniel Shoup
- Rocky Mountain Laboratories, Laboratory of Neurological Infections and Immunity, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
| | - Suzette A Priola
- Rocky Mountain Laboratories, Laboratory of Neurological Infections and Immunity, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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2
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Hivare P, Mujmer K, Swarup G, Gupta S, Bhatia D. Endocytic pathways of pathogenic protein aggregates in neurodegenerative diseases. Traffic 2023; 24:434-452. [PMID: 37392160 DOI: 10.1111/tra.12906] [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: 09/20/2022] [Revised: 05/14/2023] [Accepted: 06/11/2023] [Indexed: 07/03/2023]
Abstract
Endocytosis is the fundamental uptake process through which cells internalize extracellular materials and species. Neurodegenerative diseases (NDs) are characterized by a progressive accumulation of intrinsically disordered protein species, leading to neuronal death. Misfolding in many proteins leads to various NDs such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and other disorders. Despite the significance of disordered protein species in neurodegeneration, their spread between cells and the cellular uptake of extracellular species is not entirely understood. This review discusses the major internalization mechanisms of the different conformer species of these proteins and their endocytic mechanisms. We briefly introduce the broad types of endocytic mechanisms found in cells and then summarize what is known about the endocytosis of monomeric, oligomeric and aggregated conformations of tau, Aβ, α-Syn, Huntingtin, Prions, SOD1, TDP-43 and other proteins associated with neurodegeneration. We also highlight the key players involved in internalizing these disordered proteins and the several techniques and approaches to identify their endocytic mechanisms. Finally, we discuss the obstacles involved in studying the endocytosis of these protein species and the need to develop better techniques to elucidate the uptake mechanisms of a particular disordered protein species.
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Affiliation(s)
- Pravin Hivare
- Biological Engineering Discipline, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, India
| | - Kratika Mujmer
- Center for Brain and Cognitive Sciences, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, India
| | - Gitanjali Swarup
- Biological Engineering Discipline, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, India
| | - Sharad Gupta
- Biological Engineering Discipline, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, India
- Center for Biomedical Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, India
| | - Dhiraj Bhatia
- Biological Engineering Discipline, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, India
- Center for Biomedical Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, India
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3
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Shoup D, Priola SA. Cell biology of prion strains in vivo and in vitro. Cell Tissue Res 2023; 392:269-283. [PMID: 35107622 PMCID: PMC11249200 DOI: 10.1007/s00441-021-03572-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/22/2021] [Indexed: 02/01/2023]
Abstract
The properties of infectious prions and the pathology of the diseases they cause are dependent upon the unique conformation of each prion strain. How the pathology of prion disease correlates with different strains and genetic backgrounds has been investigated via in vivo assays, but how interactions between specific prion strains and cell types contribute to the pathology of prion disease has been dissected more effectively using in vitro cell lines. Observations made through in vivo and in vitro assays have informed each other with regard to not only how genetic variation influences prion properties, but also how infectious prions are taken up by cells, modified by cellular processes and propagated, and the cellular components they rely on for persistent infection. These studies suggest that persistent cellular infection results from a balance between prion propagation and degradation. This balance may be shifted depending upon how different cell lines process infectious prions, potentially altering prion stability, and how fast they can be transported to the lysosome. Thus, in vitro studies have given us a deeper understanding of the interactions between different prions and cell types and how they may influence prion disease phenotypes in vivo.
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Affiliation(s)
- Daniel Shoup
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Hamilton, MT, 59840, USA
| | - Suzette A Priola
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Hamilton, MT, 59840, USA.
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4
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Prion Propagation is Dependent on Key Amino Acids in Charge Cluster 2 within the Prion Protein. J Mol Biol 2023; 435:167925. [PMID: 36535427 DOI: 10.1016/j.jmb.2022.167925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/08/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
To dissect the N-terminal residues within the cellular prion protein (PrPC) that are critical for efficient prion propagation, we generated a library of point, double, or triple alanine replacements within residues 23-111 of PrP, stably expressed them in cells silenced for endogenous mouse PrPC and challenged the reconstituted cells with four common but biologically diverse mouse prion strains. Amino acids (aa) 105-111 of Charge Cluster 2 (CC2), which is disordered in PrPC, were found to be required for propagation of all four prion strains; other residues had no effect or exhibited strain-specific effects. Replacements in CC2, including aa105-111, dominantly inhibited prion propagation in the presence of endogenous wild type PrPC whilst other changes were not inhibitory. Single alanine replacements within aa105-111 identified leucine 108 and valine 111 or the cluster of lysine 105, threonine 106 and asparagine 107 as critical for prion propagation. These residues mediate specific ordering of unstructured CC2 into β-sheets in the infectious prion fibrils from Rocky Mountain Laboratory (RML) and ME7 mouse prion strains.
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5
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Alves Conceição C, Assis de Lemos G, Barros CA, Vieira TCRG. What is the role of lipids in prion conversion and disease? Front Mol Neurosci 2023; 15:1032541. [PMID: 36704327 PMCID: PMC9871914 DOI: 10.3389/fnmol.2022.1032541] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023] Open
Abstract
The molecular cause of transmissible spongiform encephalopathies (TSEs) involves the conversion of the cellular prion protein (PrPC) into its pathogenic form, called prion scrapie (PrPSc), which is prone to the formation of amorphous and amyloid aggregates found in TSE patients. Although the mechanisms of conversion of PrPC into PrPSc are not entirely understood, two key points are currently accepted: (i) PrPSc acts as a seed for the recruitment of native PrPC, inducing the latter's conversion to PrPSc; and (ii) other biomolecules, such as DNA, RNA, or lipids, can act as cofactors, mediating the conversion from PrPC to PrPSc. Interestingly, PrPC is anchored by a glycosylphosphatidylinositol molecule in the outer cell membrane. Therefore, interactions with lipid membranes or alterations in the membranes themselves have been widely investigated as possible factors for conversion. Alone or in combination with RNA molecules, lipids can induce the formation of PrP in vitro-produced aggregates capable of infecting animal models. Here, we discuss the role of lipids in prion conversion and infectivity, highlighting the structural and cytotoxic aspects of lipid-prion interactions. Strikingly, disorders like Alzheimer's and Parkinson's disease also seem to be caused by changes in protein structure and share pathogenic mechanisms with TSEs. Thus, we posit that comprehending the process of PrP conversion is relevant to understanding critical events involved in a variety of neurodegenerative disorders and will contribute to developing future therapeutic strategies for these devastating conditions.
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Affiliation(s)
- Cyntia Alves Conceição
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil,National Institute of Science and Technology for Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gabriela Assis de Lemos
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil,National Institute of Science and Technology for Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Caroline Augusto Barros
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil,National Institute of Science and Technology for Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Tuane C. R. G. Vieira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil,National Institute of Science and Technology for Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil,*Correspondence: Tuane C. R. G. Vieira, ✉
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6
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Celauro L, Zattoni M, Legname G. Prion receptors, prion internalization, intra- and inter-cellular transport. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 196:15-41. [PMID: 36813357 DOI: 10.1016/bs.pmbts.2022.06.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Luigi Celauro
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Marco Zattoni
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
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7
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Heumüller SE, Hornberger AC, Hebestreit AS, Hossinger A, Vorberg IM. Propagation and Dissemination Strategies of Transmissible Spongiform Encephalopathy Agents in Mammalian Cells. Int J Mol Sci 2022; 23:ijms23062909. [PMID: 35328330 PMCID: PMC8949484 DOI: 10.3390/ijms23062909] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/25/2022] [Accepted: 03/01/2022] [Indexed: 01/08/2023] Open
Abstract
Transmissible spongiform encephalopathies or prion disorders are fatal infectious diseases that cause characteristic spongiform degeneration in the central nervous system. The causative agent, the so-called prion, is an unconventional infectious agent that propagates by converting the host-encoded cellular prion protein PrP into ordered protein aggregates with infectious properties. Prions are devoid of coding nucleic acid and thus rely on the host cell machinery for propagation. While it is now established that, in addition to PrP, other cellular factors or processes determine the susceptibility of cell lines to prion infection, exact factors and cellular processes remain broadly obscure. Still, cellular models have uncovered important aspects of prion propagation and revealed intercellular dissemination strategies shared with other intracellular pathogens. Here, we summarize what we learned about the processes of prion invasion, intracellular replication and subsequent dissemination from ex vivo cell models.
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Affiliation(s)
- Stefanie-Elisabeth Heumüller
- Laboratory of Prion Cell Biology, German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Venusberg-Campus 1/99, 53127 Bonn, Germany; (S.-E.H.); (A.C.H.); (A.S.H.); (A.H.)
| | - Annika C. Hornberger
- Laboratory of Prion Cell Biology, German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Venusberg-Campus 1/99, 53127 Bonn, Germany; (S.-E.H.); (A.C.H.); (A.S.H.); (A.H.)
| | - Alina S. Hebestreit
- Laboratory of Prion Cell Biology, German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Venusberg-Campus 1/99, 53127 Bonn, Germany; (S.-E.H.); (A.C.H.); (A.S.H.); (A.H.)
| | - André Hossinger
- Laboratory of Prion Cell Biology, German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Venusberg-Campus 1/99, 53127 Bonn, Germany; (S.-E.H.); (A.C.H.); (A.S.H.); (A.H.)
| | - Ina M. Vorberg
- Laboratory of Prion Cell Biology, German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Venusberg-Campus 1/99, 53127 Bonn, Germany; (S.-E.H.); (A.C.H.); (A.S.H.); (A.H.)
- German Center for Neurodegenerative Diseases (DZNE), Rheinische Friedrich-Wilhelms-Universität Bonn, Siegmund-Freud-Str. 25, 53127 Bonn, Germany
- Correspondence:
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8
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Yoshida S, Hasegawa T. Deciphering the prion-like behavior of pathogenic protein aggregates in neurodegenerative diseases. Neurochem Int 2022; 155:105307. [PMID: 35181393 DOI: 10.1016/j.neuint.2022.105307] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/12/2022] [Accepted: 02/13/2022] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases are hitherto classified based on their core clinical features, the anatomical distribution of neurodegeneration, and the cell populations mainly affected. On the other hand, the wealth of neuropathological, genetic, molecular and biochemical studies have identified the existence of distinct insoluble protein aggregates in the affected brain regions. These findings have spread the use of a collective term, proteinopathy, for neurodegenerative disorders with particular type of structurally altered protein accumulation. Particularly, a recent breakthrough in this field came with the discovery that these protein aggregates can transfer from one cell to another, thereby converting normal proteins to potentially toxic, misfolded species in a prion-like manner. In this review, we focus specifically on the molecular and cellular basis that underlies the seeding activity and transcellular spreading phenomenon of neurodegeneration-related protein aggregates, and discuss how these events contribute to the disease progression.
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Affiliation(s)
- Shun Yoshida
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 9808574, Japan; Department of Neurology, National Hospital Organization Yonezawa Hospital, Yonezawa, Yamagata, 992-1202, Japan
| | - Takafumi Hasegawa
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 9808574, Japan.
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9
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Chassefeyre R, Chaiamarit T, Verhelle A, Novak SW, Andrade LR, Leitão ADG, Manor U, Encalada SE. Endosomal sorting drives the formation of axonal prion protein endoggresomes. SCIENCE ADVANCES 2021; 7:eabg3693. [PMID: 34936461 PMCID: PMC8694590 DOI: 10.1126/sciadv.abg3693] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 11/05/2021] [Indexed: 05/15/2023]
Abstract
The pathogenic aggregation of misfolded prion protein (PrP) in axons underlies prion disease pathologies. The molecular mechanisms driving axonal misfolded PrP aggregate formation leading to neurotoxicity are unknown. We found that the small endolysosomal guanosine triphosphatase (GTPase) Arl8b recruits kinesin-1 and Vps41 (HOPS) onto endosomes carrying misfolded mutant PrP to promote their axonal entry and homotypic fusion toward aggregation inside enlarged endomembranes that we call endoggresomes. This axonal rapid endosomal sorting and transport-dependent aggregation (ARESTA) mechanism forms pathologic PrP endoggresomes that impair calcium dynamics and reduce neuronal viability. Inhibiting ARESTA diminishes endoggresome formation, rescues calcium influx, and prevents neuronal death. Our results identify ARESTA as a key pathway for the regulation of endoggresome formation and a new actionable antiaggregation target to ameliorate neuronal dysfunction in the prionopathies.
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Affiliation(s)
- Romain Chassefeyre
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tai Chaiamarit
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Adriaan Verhelle
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sammy Weiser Novak
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Leonardo R. Andrade
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - André D. G. Leitão
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Sandra E. Encalada
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
- Neurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037, USA
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10
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Shoup D, Priola SA. The Size and Stability of Infectious Prion Aggregates Fluctuate Dynamically during Cellular Uptake and Disaggregation. Biochemistry 2021; 60:398-411. [PMID: 33497187 DOI: 10.1021/acs.biochem.0c00923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prion diseases arise when PrPSc, an aggregated, infectious, and insoluble conformer of the normally soluble mammalian prion protein, PrPC, catalyzes the conversion of PrPC into more PrPSc, which then accumulates in the brain leading to disease. PrPSc is the primary, if not sole, component of the infectious prion. Despite the stability and protease insensitivity of PrPSc aggregates, they can be degraded after cellular uptake. However, how cells disassemble and degrade PrPSc is poorly understood. In this work, we analyzed how the protease sensitivity and size distribution of PrPSc aggregates from two different mouse-adapted prion strains, 22L, that can persistently infect cells and 87V, that cannot, changed during cellular uptake. We show that within the first 4 h following uptake large PrPSc aggregates from both prion strains become less resistant to digestion by proteinase K (PK) through a mechanism that is dependent upon the acidic environment of endocytic vesicles. We further show that during disassembly, PrPSc aggregates from both strains become more resistant to PK digestion through the apparent removal of protease-sensitive PrPSc, with PrPSc from the 87V strain disassembled more readily than PrPSc from the 22L strain. Taken together, our data demonstrate that the sizes and stabilities of PrPSc from different prion strains change during cellular uptake and degradation, thereby potentially impacting the ability of prions to infect cells.
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Affiliation(s)
- Daniel Shoup
- Rocky Mountain Laboratories, Laboratory of Persistent Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, United States
| | - Suzette A Priola
- Rocky Mountain Laboratories, Laboratory of Persistent Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, United States
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Pineau H, Sim VL. From Cell Culture to Organoids-Model Systems for Investigating Prion Strain Characteristics. Biomolecules 2021; 11:biom11010106. [PMID: 33466947 PMCID: PMC7830147 DOI: 10.3390/biom11010106] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/06/2023] Open
Abstract
Prion diseases are the hallmark protein folding neurodegenerative disease. Their transmissible nature has allowed for the development of many different cellular models of disease where prion propagation and sometimes pathology can be induced. This review examines the range of simple cell cultures to more complex neurospheres, organoid, and organotypic slice cultures that have been used to study prion disease pathogenesis and to test therapeutics. We highlight the advantages and disadvantages of each system, giving special consideration to the importance of strains when choosing a model and when interpreting results, as not all systems propagate all strains, and in some cases, the technique used, or treatment applied, can alter the very strain properties being studied.
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Affiliation(s)
- Hailey Pineau
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2B7, Canada;
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Valerie L. Sim
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2B7, Canada;
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2R3, Canada
- Correspondence:
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12
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A New Take on Prion Protein Dynamics in Cellular Trafficking. Int J Mol Sci 2020; 21:ijms21207763. [PMID: 33092231 PMCID: PMC7589859 DOI: 10.3390/ijms21207763] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022] Open
Abstract
The mobility of cellular prion protein (PrPC) in specific cell membrane domains and among distinct cell compartments dictates its molecular interactions and directs its cell function. PrPC works in concert with several partners to organize signaling platforms implicated in various cellular processes. The scaffold property of PrPC is able to gather a molecular repertoire to create heterogeneous membrane domains that favor endocytic events. Dynamic trafficking of PrPC through multiple pathways, in a well-orchestrated mechanism of intra and extracellular vesicular transport, defines its functional plasticity, and also assists the conversion and spreading of its infectious isoform associated with neurodegenerative diseases. In this review, we highlight how PrPC traffics across intra- and extracellular compartments and the consequences of this dynamic transport in governing cell functions and contributing to prion disease pathogenesis.
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The Role of Vesicle Trafficking Defects in the Pathogenesis of Prion and Prion-Like Disorders. Int J Mol Sci 2020; 21:ijms21197016. [PMID: 32977678 PMCID: PMC7582986 DOI: 10.3390/ijms21197016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 11/26/2022] Open
Abstract
Prion diseases are fatal and transmissible neurodegenerative diseases in which the cellular form of the prion protein ‘PrPc’, misfolds into an infectious and aggregation prone isoform termed PrPSc, which is the primary component of prions. Many neurodegenerative diseases, like Alzheimer’s disease, Parkinson’s disease, and polyglutamine diseases, such as Huntington’s disease, are considered prion-like disorders because of the common characteristics in the propagation and spreading of misfolded proteins that they share with the prion diseases. Unlike prion diseases, these are non-infectious outside experimental settings. Many vesicular trafficking impairments, which are observed in prion and prion-like disorders, favor the accumulation of the pathogenic amyloid aggregates. In addition, many of the vesicular trafficking impairments that arise in these diseases, turn out to be further aggravating factors. This review offers an insight into the currently known vesicular trafficking defects in these neurodegenerative diseases and their implications on disease progression. These findings suggest that these impaired trafficking pathways may represent similar therapeutic targets in these classes of neurodegenerative disorders.
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14
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Global analysis of protein degradation in prion infected cells. Sci Rep 2020; 10:10800. [PMID: 32612191 PMCID: PMC7329860 DOI: 10.1038/s41598-020-67505-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 04/06/2020] [Indexed: 12/02/2022] Open
Abstract
Prion diseases are rare, neurological disorders caused by the misfolding of the cellular prion protein (PrPC) into cytotoxic fibrils (PrPSc). Intracellular PrPSc aggregates primarily accumulate within late endosomes and lysosomes, organelles that participate in the degradation and turnover of a large subset of the proteome. Thus, intracellular accumulation of PrPSc aggregates has the potential to globally influence protein degradation kinetics within an infected cell. We analyzed the proteome-wide effect of prion infection on protein degradation rates in N2a neuroblastoma cells by dynamic stable isotopic labeling with amino acids in cell culture (dSILAC) and bottom-up proteomics. The analysis quantified the degradation rates of more than 4,700 proteins in prion infected and uninfected cells. As expected, the degradation rate of the prion protein is significantly decreased upon aggregation in infected cells. In contrast, the degradation kinetics of the remainder of the N2a proteome generally increases upon prion infection. This effect occurs concurrently with increases in the cellular activities of autophagy and some lysosomal hydrolases. The resulting enhancement in proteome flux may play a role in the survival of N2a cells upon prion infection.
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15
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Michiels E, Roose K, Gallardo R, Khodaparast L, Khodaparast L, van der Kant R, Siemons M, Houben B, Ramakers M, Wilkinson H, Guerreiro P, Louros N, Kaptein SJF, Ibañez LI, Smet A, Baatsen P, Liu S, Vorberg I, Bormans G, Neyts J, Saelens X, Rousseau F, Schymkowitz J. Reverse engineering synthetic antiviral amyloids. Nat Commun 2020; 11:2832. [PMID: 32504029 PMCID: PMC7275043 DOI: 10.1038/s41467-020-16721-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 05/12/2020] [Indexed: 11/14/2022] Open
Abstract
Human amyloids have been shown to interact with viruses and interfere with viral replication. Based on this observation, we employed a synthetic biology approach in which we engineered virus-specific amyloids against influenza A and Zika proteins. Each amyloid shares a homologous aggregation-prone fragment with a specific viral target protein. For influenza we demonstrate that a designer amyloid against PB2 accumulates in influenza A-infected tissue in vivo. Moreover, this amyloid acts specifically against influenza A and its common PB2 polymorphisms, but not influenza B, which lacks the homologous fragment. Our model amyloid demonstrates that the sequence specificity of amyloid interactions has the capacity to tune amyloid-virus interactions while allowing for the flexibility to maintain activity on evolutionary diverging variants. Some human amyloid proteins have been shown to interact with viral proteins, suggesting that they may have potential as therapeutic agents. Here the authors design synthetic amyloids specific for influenza A and Zika virus proteins, respectively, and show that they can inhibit viral replication.
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Affiliation(s)
- Emiel Michiels
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Kenny Roose
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Rodrigo Gallardo
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Ladan Khodaparast
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Laleh Khodaparast
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Rob van der Kant
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Maxime Siemons
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.,Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Bert Houben
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Meine Ramakers
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Hannah Wilkinson
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Patricia Guerreiro
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Nikolaos Louros
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Suzanne J F Kaptein
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
| | - Lorena Itatí Ibañez
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Anouk Smet
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Pieter Baatsen
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Electron Microscopy Platform of VIB Bio Imaging Core, KU Leuven, Leuven, Belgium
| | - Shu Liu
- German Center for Neurodegenerative Diseases (DZNE e.V.), Bonn, Germany
| | - Ina Vorberg
- German Center for Neurodegenerative Diseases (DZNE e.V.), Bonn, Germany.,Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Guy Bormans
- Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Johan Neyts
- Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
| | - Xavier Saelens
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Frederic Rousseau
- VIB Center for Brain and Disease Research, Leuven, Belgium. .,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.
| | - Joost Schymkowitz
- VIB Center for Brain and Disease Research, Leuven, Belgium. .,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.
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16
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Tavassoly O, Yue J, Vocadlo DJ. Pharmacological inhibition and knockdown of O-GlcNAcase reduces cellular internalization of α-synuclein preformed fibrils. FEBS J 2020; 288:452-470. [PMID: 32365408 DOI: 10.1111/febs.15349] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/25/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022]
Abstract
The pathological hallmark of Parkinson's disease (PD) is Lewy bodies that form within the brain from aggregated forms of α-synuclein (α-syn). These toxic α-syn aggregates are transferred from cell to cell by release of fibrils from dying neurons into the extracellular environment, followed by their subsequent uptake by neighboring cells. This process leads to spreading of the pathology throughout the brain in a prion-like manner. Identifying new pathways that hinder the internalization of such α-syn fibrils is of high interest for their downstream potential exploitation as a way to create disease-modifying therapeutics for PD. Here, we show that Thiamet-G, a highly selective pharmacological agent that inhibits the glycoside hydrolase O-GlcNAcase (OGA), blunts the cellular uptake of α-syn fibrils. This effect correlates with increased nucleocytoplasmic levels of O-linked N-acetylglucosamine (O-GlcNAc)-modified proteins, and genetic knockdown of OGA expression closely phenocopies both these effects. These reductions in the uptake of α-syn fibrils caused by inhibition of OGA are both concentration- and time-dependent and are observed in multiple cell lines including mouse primary cortical neurons. Moreover, treatment of cells with the OGT inhibitor, 5SGlcNHex, increases the level of uptake of α-syn PFFs, further supporting O-GlcNAcylation of proteins driving these effects. Notably, this effect is mediated through an unknown mechanism that does not involve well-characterized endocytotic pathways. These data suggest one mechanism by which OGA inhibitors might exert their protective effects in prion-like neuropathologies and support exploration of OGA inhibitors as a potential disease-modifying approach to treat PD.
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Affiliation(s)
- Omid Tavassoly
- Department of Chemistry, Simon Fraser University, Burnaby, Canada
| | - Jefferey Yue
- Department of Chemistry, Simon Fraser University, Burnaby, Canada
| | - David J Vocadlo
- Department of Chemistry, Simon Fraser University, Burnaby, Canada.,Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
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17
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Burke CM, Walsh DJ, Mark KMK, Deleault NR, Nishina KA, Agrimi U, Di Bari MA, Supattapone S. Cofactor and glycosylation preferences for in vitro prion conversion are predominantly determined by strain conformation. PLoS Pathog 2020; 16:e1008495. [PMID: 32294141 PMCID: PMC7185723 DOI: 10.1371/journal.ppat.1008495] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/27/2020] [Accepted: 03/24/2020] [Indexed: 11/18/2022] Open
Abstract
Prion diseases are caused by the misfolding of a host-encoded glycoprotein, PrPC, into a pathogenic conformer, PrPSc. Infectious prions can exist as different strains, composed of unique conformations of PrPSc that generate strain-specific biological traits, including distinctive patterns of PrPSc accumulation throughout the brain. Prion strains from different animal species display different cofactor and PrPC glycoform preferences to propagate efficiently in vitro, but it is unknown whether these molecular preferences are specified by the amino acid sequence of PrPC substrate or by the conformation of PrPSc seed. To distinguish between these two possibilities, we used bank vole PrPC to propagate both hamster or mouse prions (which have distinct cofactor and glycosylation preferences) with a single, common substrate. We performed reconstituted sPMCA reactions using either (1) phospholipid or RNA cofactor molecules, or (2) di- or un-glycosylated bank vole PrPC substrate. We found that prion strains from either species are capable of propagating efficiently using bank vole PrPC substrates when reactions contained the same PrPC glycoform or cofactor molecule preferred by the PrPSc seed in its host species. Thus, we conclude that it is the conformation of the input PrPSc seed, not the amino acid sequence of the PrPC substrate, that primarily determines species-specific cofactor and glycosylation preferences. These results support the hypothesis that strain-specific patterns of prion neurotropism are generated by selection of differentially distributed cofactors molecules and/or PrPC glycoforms during prion replication.
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Affiliation(s)
- Cassandra M. Burke
- Departments of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Daniel J. Walsh
- Departments of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Kenneth M. K. Mark
- Departments of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Nathan R. Deleault
- Departments of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Koren A. Nishina
- Departments of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Umberto Agrimi
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Michele A. Di Bari
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Surachai Supattapone
- Departments of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
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18
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Holec SA, Block AJ, Bartz JC. The role of prion strain diversity in the development of successful therapeutic treatments. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:77-119. [PMID: 32958242 PMCID: PMC8939712 DOI: 10.1016/bs.pmbts.2020.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Prions are a self-propagating misfolded conformation of a cellular protein. Prions are found in several eukaryotic organisms with mammalian prion diseases encompassing a wide range of disorders. The first recognized prion disease, the transmissible spongiform encephalopathies (TSEs), affect several species including humans. Alzheimer's disease, synucleinopathies, and tauopathies share a similar mechanism of self-propagation of the prion form of the disease-specific protein reminiscent of the infection process of TSEs. Strain diversity in prion disease is characterized by differences in the phenotype of disease that is hypothesized to be encoded by strain-specific conformations of the prion form of the disease-specific protein. Prion therapeutics that target the prion form of the disease-specific protein can lead to the emergence of drug-resistant strains of prions, consistent with the hypothesis that prion strains exist as a dynamic mixture of a dominant strain in combination with minor substrains. To overcome this obstacle, therapies that reduce or eliminate the template of conversion are efficacious, may reverse neuropathology, and do not result in the emergence of drug resistance. Recent advancements in preclinical diagnosis of prion infection may allow for a combinational approach that treats the prion form and the precursor protein to effectively treat prion diseases.
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Affiliation(s)
- Sara A.M. Holec
- Institute for Applied Life Sciences and Department of Biology, University of Massachusetts Amherst, Amherst, MA, United States,Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States
| | - Alyssa J. Block
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States,Corresponding author:
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19
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Philiastides A, Ribes JM, Yip DCM, Schmidt C, Benilova I, Klöhn PC. A New Cell Model for Investigating Prion Strain Selection and Adaptation. Viruses 2019; 11:v11100888. [PMID: 31546723 PMCID: PMC6832381 DOI: 10.3390/v11100888] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 09/11/2019] [Indexed: 11/17/2022] Open
Abstract
Prion diseases are fatal neurodegenerative diseases that affect humans and animals. Prion strains, conformational variants of misfolded prion proteins, are associated with distinct clinical and pathological phenotypes. Host-strain interactions result in the selective damage of distinct brain areas and they are responsible for strain selection and/or adaptation, but the underlying molecular mechanisms are unknown. Prion strains can be distinguished by their cell tropism in vivo and in vitro, which suggests that susceptibility to distinct prion strains is determined by cellular factors. The neuroblastoma cell line PK1 is refractory to the prion strain Me7, but highly susceptible to RML. We challenged a large number of clonal PK1 lines with Me7 and successfully selected highly Me7-susceptible subclones (PME) to investigate whether the prion strain repertoire of PK1 can be expanded. Notably, the Me7-infected PME clones were more protease-resistant when compared to RML-infected PME clones, which suggested that cell-adapted Me7 and RML are distinct prion strains. Strikingly, Me7-refractory cells, including PK1 and astrocytes in cortico-hippocampal cultures, are highly susceptible to prions, being derived from homogenates of Me7-infected PME cells, suggesting that the passage of Me7 in PME cells leads to an extended host range. Thus, PME clones represent a compelling cell model for strain selection and adaptation.
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Affiliation(s)
- Alexandra Philiastides
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London W1W7FF, UK.
| | - Juan Manuel Ribes
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London W1W7FF, UK.
| | - Daniel Chun-Mun Yip
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London W1W7FF, UK.
| | - Christian Schmidt
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London W1W7FF, UK.
| | - Iryna Benilova
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London W1W7FF, UK.
| | - Peter-Christian Klöhn
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London W1W7FF, UK.
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20
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Hilgemann DW, Lin MJ, Fine M, Deisl C. On the existence of endocytosis driven by membrane phase separations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183007. [PMID: 31202864 DOI: 10.1016/j.bbamem.2019.06.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/31/2019] [Accepted: 06/06/2019] [Indexed: 01/15/2023]
Abstract
Large endocytic responses can occur rapidly in diverse cell types without dynamins, clathrin, or actin remodeling. Our experiments suggest that membrane phase separations are crucial with more ordered plasma membrane domains being internalized. Not only do these endocytic processes rely on coalescence of membrane domains, they are promoted by participation of membrane proteins in such domains, one important regulatory influence being palmitoylation. Membrane actin cytoskeleton in general resists membrane phase transitions, and its remodeling may play many roles. Besides membrane 'caging' and 'pinching' roles, typically ascribed to clathrin and dynamins, cytoskeleton remodeling may modify local membrane tension and buckling, as well as the presence and location of actin- and tension-free membrane patches. Endocytosis that depends on membrane phase separations becomes activated in metabolic stress and in response to Ca and PI3 kinase signaling. Internalized membrane traffics normally, and the secretory pathway eventually resupplies membrane to the plasmalemma or directs internalized membrane to other locations, including the extracellular space as exosomes. We describe here that endocytosis driven by membrane phase transitions is regulated by the same signaling mechanisms that regulate macropinocytosis, and it may play diverse roles in cells from nutrient assimilation to membrane recycling, cell migration, and the initiation of quiescent or hibernating cell states. Membrane ordering and phase separations have been shown to promote endocytosis in diverse cell types, including fibroblasts, myocytes, glial cells, and immune cells. We propose that clathrin/dynamin-independent endocytosis represents a continuum of related mechanisms with variable but universal dependence on membrane ordering and actin remodeling. This article is part of a Special Issue entitled: Molecular biophysics of membranes and membrane proteins.
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Affiliation(s)
- Donald W Hilgemann
- University of Texas Southwestern Medical Center, Department of Physiology, 5323 Harry Hines Boulevard, Dallas, TX 75235-9040, USA.
| | - Mei-Jung Lin
- University of Texas Southwestern Medical Center, Department of Physiology, 5323 Harry Hines Boulevard, Dallas, TX 75235-9040, USA
| | - Michael Fine
- University of Texas Southwestern Medical Center, Department of Physiology, 5323 Harry Hines Boulevard, Dallas, TX 75235-9040, USA
| | - Christine Deisl
- University of Texas Southwestern Medical Center, Department of Physiology, 5323 Harry Hines Boulevard, Dallas, TX 75235-9040, USA
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21
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Zavodszky E, Hegde RS. Misfolded GPI-anchored proteins are escorted through the secretory pathway by ER-derived factors. eLife 2019; 8:46740. [PMID: 31094677 PMCID: PMC6541436 DOI: 10.7554/elife.46740] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/15/2019] [Indexed: 12/27/2022] Open
Abstract
We have used misfolded prion protein (PrP*) as a model to investigate how mammalian cells recognize and degrade misfolded GPI-anchored proteins. While most misfolded membrane proteins are degraded by proteasomes, misfolded GPI-anchored proteins are primarily degraded in lysosomes. Quantitative flow cytometry analysis showed that at least 85% of PrP* molecules transiently access the plasma membrane en route to lysosomes. Unexpectedly, time-resolved quantitative proteomics revealed a remarkably invariant PrP* interactome during its trafficking from the endoplasmic reticulum (ER) to lysosomes. Hence, PrP* arrives at the plasma membrane in complex with ER-derived chaperones and cargo receptors. These interaction partners were critical for rapid endocytosis because a GPI-anchored protein induced to misfold at the cell surface was not recognized effectively for degradation. Thus, resident ER factors have post-ER itineraries that not only shield misfolded GPI-anchored proteins during their trafficking, but also provide a quality control cue at the cell surface for endocytic routing to lysosomes.
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22
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Vorberg IM. All the Same? The Secret Life of Prion Strains within Their Target Cells. Viruses 2019; 11:v11040334. [PMID: 30970585 DOI: 10.3390/v11040334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 01/23/2023] Open
Abstract
Prions are infectious β-sheet-rich protein aggregates composed of misfolded prion protein (PrPSc) that do not possess coding nucleic acid. Prions replicate by recruiting and converting normal cellular PrPC into infectious isoforms. In the same host species, prion strains target distinct brain regions and cause different disease phenotypes. Prion strains are associated with biophysically distinct PrPSc conformers, suggesting that strain properties are enciphered within alternative PrPSc quaternary structures. So far it is unknown how prion strains target specific cells and initiate productive infections. Deeper mechanistic insight into the prion life cycle came from cell lines permissive to a range of different prion strains. Still, it is unknown why certain cell lines are refractory to infection by one strain but permissive to another. While pharmacologic and genetic manipulations revealed subcellular compartments involved in prion replication, little is known about strain-specific requirements for endocytic trafficking pathways. This review summarizes our knowledge on how prions replicate within their target cells and on strain-specific differences in prion cell biology.
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Affiliation(s)
- Ina M Vorberg
- German Center for Neurodegenerative Diseases (DZNE e.V.), Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
- Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany.
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23
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Vorberg I, Chiesa R. Experimental models to study prion disease pathogenesis and identify potential therapeutic compounds. Curr Opin Pharmacol 2019; 44:28-38. [PMID: 30878006 DOI: 10.1016/j.coph.2019.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/13/2019] [Accepted: 02/13/2019] [Indexed: 01/02/2023]
Abstract
Prion diseases are devastating neurodegenerative disorders for which no drugs are available. The successful development of therapeutics depends on drug screening platforms and preclinical models that recapitulate key molecular and pathological features of the disease. Innovative experimental tools have been developed over the last few years that might facilitate drug discovery, including cell-free prion replication assays and prion-infected flies. However, there is still room for improvement. Animal models of genetic prion disease are few, and only partially recapitulate the complexity of the human disorder. Moreover, we still lack a human cell culture model suitable for high-content anti-prion drug screening. This review provides an overview of the models currently used in prion research, and discusses their promise and limitations for drug discovery.
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Affiliation(s)
- Ina Vorberg
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany.
| | - Roberto Chiesa
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milan, Italy.
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24
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GPI-anchor signal sequence influences PrPC sorting, shedding and signalling, and impacts on different pathomechanistic aspects of prion disease in mice. PLoS Pathog 2019; 15:e1007520. [PMID: 30608982 PMCID: PMC6334958 DOI: 10.1371/journal.ppat.1007520] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 01/16/2019] [Accepted: 12/11/2018] [Indexed: 12/31/2022] Open
Abstract
The cellular prion protein (PrPC) is a cell surface glycoprotein attached to the membrane by a glycosylphosphatidylinositol (GPI)-anchor and plays a critical role in transmissible, neurodegenerative and fatal prion diseases. Alterations in membrane attachment influence PrPC-associated signaling, and the development of prion disease, yet our knowledge of the role of the GPI-anchor in localization, processing, and function of PrPCin vivo is limited We exchanged the PrPC GPI-anchor signal sequence of for that of Thy-1 (PrPCGPIThy-1) in cells and mice. We show that this modifies the GPI-anchor composition, which then lacks sialic acid, and that PrPCGPIThy-1 is preferentially localized in axons and is less prone to proteolytic shedding when compared to PrPC. Interestingly, after prion infection, mice expressing PrPCGPIThy-1 show a significant delay to terminal disease, a decrease of microglia/astrocyte activation, and altered MAPK signaling when compared to wild-type mice. Our results are the first to demonstrate in vivo, that the GPI-anchor signal sequence plays a fundamental role in the GPI-anchor composition, dictating the subcellular localization of a given protein and, in the case of PrPC, influencing the development of prion disease. The prion protein (PrPC) is a glycoprotein attached to the neuronal surface via a GPI-anchor. When misfolded to PrPSc, it leads to fatal neurodegenerative diseases which propagates from host to host. PrPSc is the principal component of the infectious agent of prion diseases, the “prion”. Misfolding occurs at the plasma membrane, and when PrPC lacks the GPI-anchor, neuropathology and incubation time of prion disease are strongly modified. Moreover, the composition of the PrPC GPI-anchor impacts on the conversion process. To study the role of the GPI-anchor in the pathophysiology of prion diseases in vivo, we have generated transgenic mice where the PrPC GPI-signal sequence (GPI-SS) is replaced for the one of Thy-1, a neuronal protein with a distinct GPI-anchor and membrane localization. We found that the resulting protein, PrPCGPIThy-1, shows a different GPI-anchor composition, increased axonal localization, and reduced enzymatic shedding. After prion infection, disease progression is significantly delayed, and the neuropathology and cellular signaling are changed. The present work demonstrates that the GPI-SS per se determines the GPI-anchor composition and localization of a given protein and it stresses the importance of PrPC membrane anchorage in prion disease.
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25
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Combet S, Cousin F, Rezaei H, Noinville S. Membrane interaction of off-pathway prion oligomers and lipid-induced on-pathway intermediates during prion conversion: A clue for neurotoxicity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:514-523. [PMID: 30529078 DOI: 10.1016/j.bbamem.2018.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/21/2018] [Accepted: 12/04/2018] [Indexed: 12/31/2022]
Abstract
Soluble oligomers of prion proteins (PrP), produced during amyloid aggregation, have emerged as the primary neurotoxic species, instead of the fibrillar end-products, in transmissible spongiform encephalopathies. However, whether the membrane is among their direct targets, that mediate the downstream adverse effects, remains a question of debate. Recently, questions arise from the formation of membrane-active oligomeric species generated during the β-aggregation pathway, either in solution, or in lipid environment. In the present study, we characterized membrane interaction of off-pathway oligomers from recombinant prion protein generated along the amyloid aggregation and compared to lipid-induced intermediates produced during lipid-accelerated fibrillation. Using calcein-leakage assay, we show that the soluble prion oligomers are the most potent in producing leakage with negatively charged vesicles. Binding affinities, conformational states, mode of action of the different PrP assemblies were determined by thioflavin T binding-static light scattering experiments on DOPC/DOPS vesicles, as well as by FTIR-ATR spectroscopy and specular neutron reflectivity onto the corresponding supported lipid bilayers. Our results indicate that the off-pathway PrP oligomers interact with lipid membrane via a distinct mechanism, compared to the inserted lipid-induced intermediates. Thus, separate neurotoxic mechanisms could exist following the puzzling intermediates generated in the different cell compartments. These results not only reveal an important regulation of lipid membrane on PrP behavior but may also provide clues for designing stage-specific and prion-targeted therapy.
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Affiliation(s)
- Sophie Combet
- Laboratoire Léon-Brillouin, UMR 12 CEA-CNRS, Université Paris-Saclay, CEA-Saclay, F-91191 Gif-sur-Yvette CEDEX, France
| | - Fabrice Cousin
- Laboratoire Léon-Brillouin, UMR 12 CEA-CNRS, Université Paris-Saclay, CEA-Saclay, F-91191 Gif-sur-Yvette CEDEX, France
| | - Human Rezaei
- Laboratoire de Virologie et Immunologie Moléculaires, UR892, Institut National de la Recherche Agronomique (INRA), F-78352 Jouy-en-Josas, France
| | - Sylvie Noinville
- Laboratoire MONARIS, UMR 8233, Sorbonne Université, CNRS, F-75005 Paris, France.
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Bräuer S, Zimyanin V, Hermann A. Prion-like properties of disease-relevant proteins in amyotrophic lateral sclerosis. J Neural Transm (Vienna) 2018; 125:591-613. [PMID: 29417336 DOI: 10.1007/s00702-018-1851-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/30/2018] [Indexed: 02/07/2023]
Abstract
The hallmark of age-related neurodegenerative diseases is the appearance of cellular protein deposits and spreading of this pathology throughout the central nervous system. Growing evidence has shown the involvement and critical role of proteins with prion-like properties in the formation of these characteristic cellular aggregates. Prion-like domains of such proteins with their proposed function in the organization of membraneless organelles are prone for misfolding and promoting further aggregation. Spreading of these toxic aggregates between cells and across tissues can explain the progression of clinical phenotypes and pathology in a stereotypical manner, characteristic for almost every neurodegenerative disease. Here, we want to review the current evidence for the role of prion-like mechanisms in classical neurodegenerative diseases and ALS in particular. We will also discuss an intriguingly central role of the protein TDP-43 in the majority of cases of this devastating disease.
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Affiliation(s)
- S Bräuer
- Department of Neurology, Technische Universität Dresden, Fetscherstraße 74, 01307, Dresden, Germany
- Department of Neurology, Städtisches Klinikum Dresden, 01129, Dresden, Germany
| | - V Zimyanin
- Department of Neurology, Technische Universität Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - A Hermann
- Department of Neurology, Technische Universität Dresden, Fetscherstraße 74, 01307, Dresden, Germany.
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden and German Center for Neurodegenerative Diseases (DZNE), 01307, Dresden, Germany.
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Cofactors influence the biological properties of infectious recombinant prions. Acta Neuropathol 2018; 135:179-199. [PMID: 29094186 DOI: 10.1007/s00401-017-1782-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/20/2017] [Accepted: 10/21/2017] [Indexed: 12/23/2022]
Abstract
Prion diseases are caused by a misfolding of the cellular prion protein (PrP) to a pathogenic isoform named PrPSc. Prions exist as strains, which are characterized by specific pathological and biochemical properties likely encoded in the three-dimensional structure of PrPSc. However, whether cofactors determine these different PrPSc conformations and how this relates to their specific biological properties is largely unknown. To understand how different cofactors modulate prion strain generation and selection, Protein Misfolding Cyclic Amplification was used to create a diversity of infectious recombinant prion strains by propagation in the presence of brain homogenate. Brain homogenate is known to contain these mentioned cofactors, whose identity is only partially known, and which facilitate conversion of PrPC to PrPSc. We thus obtained a mix of distinguishable infectious prion strains. Subsequently, we replaced brain homogenate, by different polyanionic cofactors that were able to drive the evolution of mixed prion populations toward specific strains. Thus, our results show that a variety of infectious recombinant prions can be generated in vitro and that their specific type of conformation, i.e., the strain, is dependent on the cofactors available during the propagation process. These observations have significant implications for understanding the pathogenesis of prion diseases and their ability to replicate in different tissues and hosts. Importantly, these considerations might apply to other neurodegenerative diseases for which different conformations of misfolded proteins have been described.
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Cheng L, Zhao W, Hill AF. Exosomes and their role in the intercellular trafficking of normal and disease associated prion proteins. Mol Aspects Med 2017; 60:62-68. [PMID: 29196098 DOI: 10.1016/j.mam.2017.11.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/08/2017] [Accepted: 11/27/2017] [Indexed: 12/13/2022]
Abstract
Over the past decade, small extracellular vesicles called exosomes have been observed to harbour protein and genetic cargo that can assist in health and also cause disease. Many groups are extensively investigating the mechanisms involved that regulate the trafficking and packaging of exosomal contents and how these processes may be deregulated in disease. Prion diseases are transmissible neurodegenerative disorders and are characterized by the presence of detectable misfolded prion proteins. The disease associated form of the prion protein can be found in exosomes and its transmissible properties have provided a reliable experimental read out that can be used to understand how exosomes and their cargo are involved in cell-cell communication and in the spread of prion diseases. This review reports on the current understanding of how exosomes are involved in the intercellular spread of infectious prions. Furthermore, we discuss how these principles are leading future investigations in developing new exosome based diagnostic tools and therapeutic drugs that could be applied to other neurodegenerative diseases.
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Affiliation(s)
- Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Wenting Zhao
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia.
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