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Bizingre C, Bianchi C, Baudry A, Alleaume-Butaux A, Schneider B, Pietri M. Post-translational modifications in prion diseases. Front Mol Neurosci 2024; 17:1405415. [PMID: 39011540 PMCID: PMC11247024 DOI: 10.3389/fnmol.2024.1405415] [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: 03/22/2024] [Accepted: 06/14/2024] [Indexed: 07/17/2024] Open
Abstract
More than 650 reversible and irreversible post-translational modifications (PTMs) of proteins have been listed so far. Canonical PTMs of proteins consist of the covalent addition of functional or chemical groups on target backbone amino-acids or the cleavage of the protein itself, giving rise to modified proteins with specific properties in terms of stability, solubility, cell distribution, activity, or interactions with other biomolecules. PTMs of protein contribute to cell homeostatic processes, enabling basal cell functions, allowing the cell to respond and adapt to variations of its environment, and globally maintaining the constancy of the milieu interieur (the body's inner environment) to sustain human health. Abnormal protein PTMs are, however, associated with several disease states, such as cancers, metabolic disorders, or neurodegenerative diseases. Abnormal PTMs alter the functional properties of the protein or even cause a loss of protein function. One example of dramatic PTMs concerns the cellular prion protein (PrPC), a GPI-anchored signaling molecule at the plasma membrane, whose irreversible post-translational conformational conversion (PTCC) into pathogenic prions (PrPSc) provokes neurodegeneration. PrPC PTCC into PrPSc is an additional type of PTM that affects the tridimensional structure and physiological function of PrPC and generates a protein conformer with neurotoxic properties. PrPC PTCC into PrPSc in neurons is the first step of a deleterious sequence of events at the root of a group of neurodegenerative disorders affecting both humans (Creutzfeldt-Jakob diseases for the most representative diseases) and animals (scrapie in sheep, bovine spongiform encephalopathy in cow, and chronic wasting disease in elk and deer). There are currently no therapies to block PrPC PTCC into PrPSc and stop neurodegeneration in prion diseases. Here, we review known PrPC PTMs that influence PrPC conversion into PrPSc. We summarized how PrPC PTCC into PrPSc impacts the PrPC interactome at the plasma membrane and the downstream intracellular controlled protein effectors, whose abnormal activation or trafficking caused by altered PTMs promotes neurodegeneration. We discussed these effectors as candidate drug targets for prion diseases and possibly other neurodegenerative diseases.
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Affiliation(s)
- Chloé Bizingre
- INSERM UMR-S 1124, Paris, France
- Université Paris Cité, UMR-S 1124, Paris, France
| | - Clara Bianchi
- INSERM UMR-S 1124, Paris, France
- Université Paris Cité, UMR-S 1124, Paris, France
| | - Anne Baudry
- INSERM UMR-S 1124, Paris, France
- Université Paris Cité, UMR-S 1124, Paris, France
| | | | - Benoit Schneider
- INSERM UMR-S 1124, Paris, France
- Université Paris Cité, UMR-S 1124, Paris, France
- Ecole polytechnique, Institut Polytechnique de Paris, CNRS UMR7654, Palaiseau, France
| | - Mathéa Pietri
- INSERM UMR-S 1124, Paris, France
- Université Paris Cité, UMR-S 1124, Paris, France
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2
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Bocharova O, Makarava N, Pandit NP, Molesworth K, Baskakov IV. Multiple steps of prion strain adaptation to a new host. Front Neurosci 2024; 18:1329010. [PMID: 38362022 PMCID: PMC10867973 DOI: 10.3389/fnins.2024.1329010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/12/2024] [Indexed: 02/17/2024] Open
Abstract
The transmission of prions across species is a critical aspect of their dissemination among mammalian hosts, including humans. This process often necessitates strain adaptation. In this study, we sought to investigate the mechanisms underlying prion adaptation while mitigating biases associated with the history of cross-species transmission of natural prion strains. To achieve this, we utilized the synthetic hamster prion strain S05. Propagation of S05 using mouse PrPC in Protein Misfolding Cyclic Amplification did not immediately overcome the species barrier. This finding underscores the involvement of factors beyond disparities in primary protein structures. Subsequently, we performed five serial passages to stabilize the incubation time to disease in mice. The levels of PrPSc increased with each passage, reaching a maximum at the third passage, and declining thereafter. This suggests that only the initial stage of adaptation is primarily driven by an acceleration in PrPSc replication. During the protracted adaptation to a new host, we observed significant alterations in the glycoform ratio and sialylation status of PrPSc N-glycans. These changes support the notion that qualitative modifications in PrPSc contribute to a more rapid disease progression. Furthermore, consistent with the decline in sialylation, a cue for "eat me" signaling, the newly adapted strain exhibited preferential colocalization with microglia. In contrast to PrPSc dynamics, the intensity of microglia activation continued to increase after the third passage in the new host. In summary, our study elucidates that the adaptation of a prion strain to a new host is a multi-step process driven by several factors.
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Affiliation(s)
- Olga Bocharova
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Narayan P. Pandit
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
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3
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Bocharova O, Makarava N, Pandit NP, Molesworth K, Baskakov IV. Multiple steps of prion strain adaptation to a new host. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563743. [PMID: 37961127 PMCID: PMC10634783 DOI: 10.1101/2023.10.24.563743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The transmission of prions across species is a critical aspect of their dissemination among mammalian hosts, including humans. This process often necessitates strain adaptation. In this study, we sought to investigate the mechanisms underlying prion adaptation while mitigating biases associated with the history of cross-species transmission of natural prion strains. To achieve this, we utilized the synthetic hamster prion strain S05. Propagation of S05 using mouse PrPC in Protein Misfolding Cyclic Amplification did not immediately overcome the species barrier. This finding underscores the involvement of factors beyond disparities in primary protein structures. Subsequently, we performed five serial passages to stabilize the incubation time to disease in mice. The levels of PrPSc increased with each passage, reaching a maximum at the third passage, and declining thereafter. This suggests that only the initial stage of adaptation is primarily driven by an acceleration in PrPSc replication. During the protracted adaptation to a new host, we observed significant alterations in the glycoform ratio and sialylation status of PrPSc N-glycans. These changes support the notion that qualitative modifications in PrPSc contribute to a more rapid disease progression. Furthermore, consistent with the decline in sialylation, a cue for "eat me" signaling, the newly adapted strain exhibited preferential colocalization with microglia. In contrast to PrPSc dynamics, the intensity of microglia activation continued to increase after the third passage in the new host. In summary, our study elucidates that the adaptation of a prion strain to a new host is a multi-step process driven by several factors.
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Affiliation(s)
- Olga Bocharova
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Narayan P. Pandit
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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4
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Kushwaha R, Li Y, Makarava N, Pandit NP, Molesworth K, Birukov KG, Baskakov IV. Reactive astrocytes associated with prion disease impair the blood brain barrier. Neurobiol Dis 2023; 185:106264. [PMID: 37597815 PMCID: PMC10494928 DOI: 10.1016/j.nbd.2023.106264] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/31/2023] [Accepted: 08/15/2023] [Indexed: 08/21/2023] Open
Abstract
BACKGROUND Impairment of the blood-brain barrier (BBB) is considered to be a common feature among neurodegenerative diseases, including Alzheimer's, Parkinson's and prion diseases. In prion disease, increased BBB permeability was reported 40 years ago, yet the mechanisms behind the loss of BBB integrity have never been explored. Recently, we showed that reactive astrocytes associated with prion diseases are neurotoxic. The current work examines the potential link between astrocyte reactivity and BBB breakdown. RESULTS In prion-infected mice, the loss of BBB integrity and aberrant localization of aquaporin 4 (AQP4), a sign of retraction of astrocytic endfeet from blood vessels, were noticeable prior to disease onset. Gaps in cell-to-cell junctions along blood vessels, together with downregulation of Occludin, Claudin-5 and VE-cadherin, which constitute tight and adherens junctions, suggested that loss of BBB integrity is linked with degeneration of vascular endothelial cells. In contrast to cells isolated from non-infected adult mice, endothelial cells originating from prion-infected mice displayed disease-associated changes, including lower levels of Occludin, Claudin-5 and VE-cadherin expression, impaired tight and adherens junctions, and reduced trans-endothelial electrical resistance (TEER). Endothelial cells isolated from non-infected mice, when co-cultured with reactive astrocytes isolated from prion-infected animals or treated with media conditioned by the reactive astrocytes, developed the disease-associated phenotype observed in the endothelial cells from prion-infected mice. Reactive astrocytes were found to produce high levels of secreted IL-6, and treatment of endothelial monolayers originating from non-infected animals with recombinant IL-6 alone reduced their TEER. Remarkably, treatment with extracellular vesicles produced by normal astrocytes partially reversed the disease phenotype of endothelial cells isolated from prion-infected animals. CONCLUSIONS To our knowledge, the current work is the first to illustrate early BBB breakdown in prion disease and to document that reactive astrocytes associated with prion disease are detrimental to BBB integrity. Moreover, our findings suggest that the harmful effects are linked to proinflammatory factors secreted by reactive astrocytes.
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Affiliation(s)
- Rajesh Kushwaha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Yue Li
- Lung Biology Research Program and Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Narayan P Pandit
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Konstantin G Birukov
- Lung Biology Research Program and Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Ilia V Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America.
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5
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Makarava N, Baskakov IV. Role of sialylation of N-linked glycans in prion pathogenesis. Cell Tissue Res 2023; 392:201-214. [PMID: 35088180 PMCID: PMC9329487 DOI: 10.1007/s00441-022-03584-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/12/2022] [Indexed: 01/10/2023]
Abstract
Mammalian prion or PrPSc is a proteinaceous infectious agent that consists of a misfolded, self-replicating state of the prion protein or PrPC. PrPC and PrPSc are posttranslationally modified with N-linked glycans, which are sialylated at the terminal positions. More than 30 years have passed since the first characterization of the composition and structural diversity of N-linked glycans associated with the prion protein, yet the role of carbohydrate groups that constitute N-glycans and, in particular, their terminal sialic acid residues in prion disease pathogenesis remains poorly understood. A number of recent studies shed a light on the role of sialylation in the biology of prion diseases. This review article discusses several mechanisms by which terminal sialylation dictates the spread of PrPSc across brain regions and the outcomes of prion infection in an organism. In particular, relationships between the sialylation status of PrPSc and important strain-specific features including lymphotropism, neurotropism, and neuroinflammation are discussed. Moreover, emerging evidence pointing out the roles of sialic acid residues in prion replication, cross-species transmission, strain competition, and strain adaptation are reviewed. A hypothesis according to which selective, strain-specified recruitment of PrPC sialoglycoforms dictates unique strain-specific disease phenotypes is examined. Finally, the current article proposes that prion strains evolve as a result of a delicate balance between recruiting highly sialylated glycoforms to avoid an "eat-me" response by glia and limiting heavily sialylated glycoforms for enabling rapid prion replication.
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ilia V Baskakov
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
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6
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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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7
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Kushwaha R, Li Y, Makarava N, Pandit NP, Molesworth K, Birukov KG, Baskakov IV. Reactive astrocytes associated with prion disease impair the blood brain barrier. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.21.533684. [PMID: 36993690 PMCID: PMC10055297 DOI: 10.1101/2023.03.21.533684] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Background Impairment of the blood-brain barrier (BBB) is considered to be a common feature among neurodegenerative diseases, including Alzheimer's, Parkinson's and prion diseases. In prion disease, increased BBB permeability was reported 40 years ago, yet the mechanisms behind the loss of BBB integrity have never been explored. Recently, we showed that reactive astrocytes associated with prion diseases are neurotoxic. The current work examines the potential link between astrocyte reactivity and BBB breakdown. Results In prion-infected mice, the loss of BBB integrity and aberrant localization of aquaporin 4 (AQP4), a sign of retraction of astrocytic endfeet from blood vessels, were noticeable prior to disease onset. Gaps in cell-to-cell junctions along blood vessels, together with downregulation of Occludin, Claudin-5 and VE-cadherin, which constitute tight and adherens junctions, suggested that loss of BBB integrity is linked with degeneration of vascular endothelial cells. In contrast to cells isolated from non-infected adult mice, endothelial cells originating from prion-infected mice displayed disease-associated changes, including lower levels of Occludin, Claudin-5 and VE-cadherin expression, impaired tight and adherens junctions, and reduced trans-endothelial electrical resistance (TEER). Endothelial cells isolated from non-infected mice, when co-cultured with reactive astrocytes isolated from prion-infected animals or treated with media conditioned by the reactive astrocytes, developed the disease-associated phenotype observed in the endothelial cells from prion-infected mice. Reactive astrocytes were found to produce high levels of secreted IL-6, and treatment of endothelial monolayers originating from non-infected animals with recombinant IL-6 alone reduced their TEER. Remarkably, treatment with extracellular vesicles produced by normal astrocytes partially reversed the disease phenotype of endothelial cells isolated from prion-infected animals. Conclusions To our knowledge, the current work is the first to illustrate early BBB breakdown in prion disease and to document that reactive astrocytes associated with prion disease are detrimental to BBB integrity. Moreover, our findings suggest that the harmful effects are linked to proinflammatory factors secreted by reactive astrocytes.
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Affiliation(s)
- Rajesh Kushwaha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
| | - Yue Li
- Lung Biology Research Program and Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, 21201
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
| | - Narayan P. Pandit
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
| | - Konstantin G. Birukov
- Lung Biology Research Program and Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, 21201
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States of America
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Dhar C. Does SIGLEC8 localize to the subcellular compartment like the Alzheimer's disease protective CD33 splice variant? Front Cell Neurosci 2023; 17:1124150. [PMID: 37124396 PMCID: PMC10133518 DOI: 10.3389/fncel.2023.1124150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/28/2023] [Indexed: 05/02/2023] Open
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Makarava N, Katorcha E, Chang JCY, Lau JTY, Baskakov IV. Deficiency in ST6GAL1, one of the two α2,6-sialyltransferases, has only a minor effect on the pathogenesis of prion disease. Front Mol Biosci 2022; 9:1058602. [PMID: 36452458 PMCID: PMC9702343 DOI: 10.3389/fmolb.2022.1058602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/31/2022] [Indexed: 10/22/2023] Open
Abstract
Prion diseases are a group of fatal neurodegenerative diseases caused by misfolding of the normal cellular form of the prion protein or PrPC, into a disease-associated self-replicating state or PrPSc. PrPC and PrPSc are posttranslationally modified with N-linked glycans, in which the terminal positions occupied by sialic acids residues are attached to galactose predominantly via α2-6 linkages. The sialylation status of PrPSc is an important determinant of prion disease pathogenesis, as it dictates the rate of prion replication and controls the fate of prions in an organism. The current study tests whether a knockout of ST6Gal1, one of the two mammalian sialyltransferases that catalyze the sialylation of glycans via α2-6 linkages, reduces the sialylation status of PrPSc and alters prion disease pathogenesis. We found that a global knockout of ST6Gal1 in mice significantly reduces the α2-6 sialylation of the brain parenchyma, as determined by staining with Sambucus Nigra agglutinin. However, the sialylation of PrPSc remained stable and the incubation time to disease increased only modestly in ST6Gal1 knockout mice (ST6Gal1-KO). A lack of significant changes in the PrPSc sialylation status and prion pathogenesis is attributed to the redundancy in sialylation and, in particular, the plausible involvement of a second member of the sialyltransferase family that sialylate via α2-6 linkages, ST6Gal2.
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Elizaveta Katorcha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Jennifer Chen-Yu Chang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Joseph T. Y. Lau
- Department of Molecular and Cellular Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, United States
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
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10
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Kobayashi A, Munesue Y, Shimazaki T, Aoshima K, Kimura T, Mohri S, Kitamoto T. Potential for transmission of sporadic Creutzfeldt-Jakob disease through peripheral routes. J Transl Med 2021; 101:1327-1330. [PMID: 34253850 DOI: 10.1038/s41374-021-00641-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 11/09/2022] Open
Abstract
Five sporadic Creutzfeldt-Jakob disease (CJD) strains have been identified to date, based on differences in clinicopathological features of the patients, the biochemical properties of abnormal prion proteins, and transmission properties. Recent advances in our knowledge about iatrogenic transmission of sporadic CJD have raised the possibility that the infectivity of sporadic CJD strains through peripheral routes is different from that of intracranial infection. To test this possibility, here we assessed systematically the infectivity of sporadic CJD strains through the peripheral route for the first time using a mouse model expressing human prion protein. Although the infectivity of the V2 and M1 sporadic CJD strains is almost the same in intracerebral transmission studies, the V2 strain infected more efficiently than the M1 strain through the peripheral route. The other sporadic CJD strains examined lacked infectivity. Of note, both the V2 and M1 strains showed preference for mice with the valine homozygosity at the PRNP polymorphic codon. These results indicate that the V2 strain is the most infectious sporadic CJD strain for infection through peripheral routes. In addition, these findings raise the possibility that individuals with the valine homozygosity at the PRNP polymorphic codon might have higher risks of infection through peripheral routes compared with the methionine homozygotes. Thus, preventive measures against the transmission of the V2 sporadic CJD strain will be important for the eradication of iatrogenic CJD transmission through peripheral routes.
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Affiliation(s)
- Atsushi Kobayashi
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
| | - Yoshiko Munesue
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Taishi Shimazaki
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Keisuke Aoshima
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Takashi Kimura
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Shirou Mohri
- Division of Neurological Science, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Tetsuyuki Kitamoto
- Division of Neurological Science, Tohoku University Graduate School of Medicine, Sendai, Japan
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11
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Sinha A, Kushwaha R, Molesworth K, Mychko O, Makarava N, Baskakov IV. Phagocytic Activities of Reactive Microglia and Astrocytes Associated with Prion Diseases Are Dysregulated in Opposite Directions. Cells 2021; 10:1728. [PMID: 34359897 PMCID: PMC8304827 DOI: 10.3390/cells10071728] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/02/2021] [Accepted: 07/04/2021] [Indexed: 01/11/2023] Open
Abstract
Phagocytosis is one of the most important physiological functions of the glia directed at maintaining a healthy, homeostatic environment in the brain. Under a homeostatic environment, the phagocytic activities of astrocytes and microglia are tightly coordinated in time and space. In neurodegenerative diseases, both microglia and astrocytes contribute to neuroinflammation and disease pathogenesis, however, whether their phagocytic activities are up- or downregulated in reactive states is not known. To address this question, this current study isolated microglia and astrocytes from C57BL/6J mice infected with prions and tested their phagocytic activities in live-cell imaging assays that used synaptosomes and myelin debris as substrates. The phagocytic uptake by the reactive microglia was found to be significantly upregulated, whereas that of the reactive astrocytes was strongly downregulated. The up- and downregulation of phagocytosis by the two cell types were observed irrespective of whether disease-associated synaptosomes, normal synaptosomes, or myelin debris were used in the assays, indicating that dysregulations are dictated by cell reactive states, not substrates. Analysis of gene expression confirmed dysregulation of phagocytic functions in both cell types. Immunostaining of animal brains infected with prions revealed that at the terminal stage of disease, neuronal cell bodies were subject to engulfment by reactive microglia. This study suggests that imbalance in the phagocytic activities of the reactive microglia and astrocytes, which are dysregulated in opposite directions, is likely to lead to excessive microglia-mediated neuronal death on the one hand, and the inability of astrocytes to clear cell debris on the other hand, contributing to the neurotoxic effects of glia as a whole.
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Affiliation(s)
- Anshuman Sinha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rajesh Kushwaha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Olga Mychko
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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12
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Abstract
Transformation of astrocytes into reactive states is considered one of the major pathological hallmarks of prion and other neurodegenerative diseases. Recent years witnessed a growing appreciation of the view that reactive astrocytes are intimately involved in chronic neurodegeneration; however, little is known about their role in disease pathogenesis. The current article reviews the progress of the last few years and critically discusses controversial questions of whether reactive astrocytes associated with prion diseases are neurotoxic or neuroprotective and whether bidirectional A1–A2 model is applicable for describing polarization of astrocytes. Moreover, other important topics, including reversibility of a transition to a reactive state, along with the role of microglia and other stimuli in triggering astrocyte activation are reviewed. Defining the role of reactive astrocytes in pathogenesis of neurodegenerative diseases will open unrealized opportunities for developing new therapeutic approaches against prion and other neurodegenerative diseases.
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Affiliation(s)
- Ilia V Baskakov
- Department of Anatomy and Neurobiology, And Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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13
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The degree of astrocyte activation is predictive of the incubation time to prion disease. Acta Neuropathol Commun 2021; 9:87. [PMID: 33980286 PMCID: PMC8114720 DOI: 10.1186/s40478-021-01192-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/03/2021] [Indexed: 12/18/2022] Open
Abstract
In neurodegenerative diseases including Alzheimer’s, Parkinson’s and prion diseases, astrocytes acquire disease-associated reactive phenotypes. With growing appreciation of their role in chronic neurodegeneration, the questions whether astrocytes lose their ability to perform homeostatic functions in the reactive states and whether the reactive phenotypes are neurotoxic or neuroprotective remain unsettled. The current work examined region-specific changes in expression of genes, which report on astrocyte physiological functions and their reactive states, in C57Black/6J mice challenged with four prion strains via two inoculation routes. Unexpectedly, strong reverse correlation between the incubation time to the diseases and the degree of astrocyte activation along with disturbance in functional pathways was observed. The animal groups with the most severe astrocyte response and degree of activation showed the most rapid disease progression. The degree of activation tightly intertwined with the global transformation of the homeostatic state, characterized by disturbances in multiple gene sets responsible for normal physiological functions producing a neurotoxic, reactive phenotype as a net result. The neurotoxic reactive phenotype exhibited a universal gene signature regardless of the prion strain. The current work suggests that the degree of astrocyte activation along with the disturbance in their physiological pathways contribute to the faster progression of disease and perhaps even drive prion pathogenesis.
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14
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Cha S, Sin MJ, Kim MJ, Kim HJ, Kim YS, Choi EK, Kim MY. Involvement of Cellular Prion Protein in Invasion and Metastasis of Lung Cancer by Inducing Treg Cell Development. Biomolecules 2021; 11:biom11020285. [PMID: 33671884 PMCID: PMC7918983 DOI: 10.3390/biom11020285] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 12/15/2022] Open
Abstract
The cellular prion protein (PrPC) is a cell surface glycoprotein expressed in many cell types that plays an important role in normal cellular processes. However, an increase in PrPC expression has been associated with a variety of human cancers, where it may be involved in resistance to the proliferation and metastasis of cancer cells. PrP-deficient (Prnp0/0) and PrP-overexpressing (Tga20) mice were studied to evaluate the role of PrPC in the invasion and metastasis of cancer. Tga20 mice, with increased PrPC, died more quickly from lung cancer than did the Prnp0/0 mice, and this effect was associated with increased transforming growth factor-beta (TGF-β) and programmed death ligand-1 (PD-L1), which are important for the development and function of regulatory T (Treg) cells. The number of FoxP3+CD25+ Treg cells was increased in Tga20 mice compared to Prnp0/0 mice, but there was no significant difference in either natural killer or cytotoxic T cell numbers. In addition, mice infected with the ME7 scrapie strain had decreased numbers of Treg cells and decreased expression of TGF-β and PD-L1. These results suggest that PrPC plays an important role in invasion and metastasis of cancer cells by inducing Treg cells through upregulation of TGF-β and PD-L1 expression.
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Affiliation(s)
- Seunghwa Cha
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Korea; (S.C.); (M.-J.S.)
| | - Mi-Ji Sin
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Korea; (S.C.); (M.-J.S.)
| | - Mo-Jong Kim
- Ilsong Institute of Life Science, Hallym University, Anyang 14066, Korea; (M.-J.K.); (H.-J.K.); (Y.-S.K.)
- Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon 24252, Korea
| | - Hee-Jun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang 14066, Korea; (M.-J.K.); (H.-J.K.); (Y.-S.K.)
| | - Yong-Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang 14066, Korea; (M.-J.K.); (H.-J.K.); (Y.-S.K.)
| | - Eun-Kyoung Choi
- Ilsong Institute of Life Science, Hallym University, Anyang 14066, Korea; (M.-J.K.); (H.-J.K.); (Y.-S.K.)
- Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon 24252, Korea
- Correspondence: (E.-K.C.); (M.-Y.K.)
| | - Mi-Yeon Kim
- School of Systems Biomedical Science, Soongsil University, Seoul 06978, Korea; (S.C.); (M.-J.S.)
- Correspondence: (E.-K.C.); (M.-Y.K.)
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15
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From Posttranslational Modifications to Disease Phenotype: A Substrate Selection Hypothesis in Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms22020901. [PMID: 33477465 PMCID: PMC7830165 DOI: 10.3390/ijms22020901] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 11/16/2022] Open
Abstract
A number of neurodegenerative diseases including prion diseases, tauopathies and synucleinopathies exhibit multiple clinical phenotypes. A diversity of clinical phenotypes has been attributed to the ability of amyloidogenic proteins associated with a particular disease to acquire multiple, conformationally distinct, self-replicating states referred to as strains. Structural diversity of strains formed by tau, α-synuclein or prion proteins has been well documented. However, the question how different strains formed by the same protein elicit different clinical phenotypes remains poorly understood. The current article reviews emerging evidence suggesting that posttranslational modifications are important players in defining strain-specific structures and disease phenotypes. This article put forward a new hypothesis referred to as substrate selection hypothesis, according to which individual strains selectively recruit protein isoforms with a subset of posttranslational modifications that fit into strain-specific structures. Moreover, it is proposed that as a result of selective recruitment, strain-specific patterns of posttranslational modifications are formed, giving rise to unique disease phenotypes. Future studies should define whether cell-, region- and age-specific differences in metabolism of posttranslational modifications play a causative role in dictating strain identity and structural diversity of strains of sporadic origin.
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16
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Baskakov IV. Role of sialylation in prion disease pathogenesis and prion structure. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:31-52. [PMID: 32958238 DOI: 10.1016/bs.pmbts.2020.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mammalian prion or PrPSc is a proteinaceous infectious agent that consists of a misfolded, self-replicating state of a sialoglycoprotein called the prion protein or PrPC. Sialylation of the prion protein, a terminal modification of N-linked glycans, was discovered more than 30 years ago, yet the role of sialylation in prion pathogenesis is not well understood. This chapter summarizes current knowledge on the role of sialylation of the prion protein in prion diseases. First, we discuss recent data suggesting that sialylation of PrPSc N-linked glycans determines the fate of prion infection in an organism and control prion lymphotropism. Second, emerging evidence pointing out at the role N-glycans in neuroinflammation are discussed. Thirds, this chapter reviews a mechanism postulating that sialylated N-linked glycans are important players in defining strain-specific structures. A new hypothesis according to which individual strain-specific PrPSc structures govern selection of PrPC sialoglycoforms is discussed. Finally, this chapter explain how N-glycan sialylation control the prion replication and strain interference. In summary, comprehensive review of our knowledge on N-linked glycans and their sialylation provided in this chapter helps to answer important questions of prion biology that have been puzzling for years.
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Affiliation(s)
- Ilia V Baskakov
- Department of Anatomy and Neurobiology, and Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States.
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17
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Makarava N, Chang JCY, Baskakov IV. Region-Specific Sialylation Pattern of Prion Strains Provides Novel Insight into Prion Neurotropism. Int J Mol Sci 2020; 21:ijms21030828. [PMID: 32012886 PMCID: PMC7037812 DOI: 10.3390/ijms21030828] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/10/2020] [Accepted: 01/23/2020] [Indexed: 12/14/2022] Open
Abstract
Mammalian prions are unconventional infectious agents that invade and replicate in an organism by recruiting a normal form of a prion protein (PrPC) and converting it into misfolded, disease-associated state referred to as PrPSc. PrPC is posttranslationally modified with two N-linked glycans. Prion strains replicate by selecting substrates from a large pool of PrPC sialoglycoforms expressed by a host. Brain regions have different vulnerability to prion infection, however, molecular mechanisms underlying selective vulnerability is not well understood. Toward addressing this question, the current study looked into a possibility that sialylation of PrPSc might be involved in defining selective vulnerability of brain regions. The current work found that in 22L -infected animals, PrPSc is indeed sialylated in a region dependent manner. PrPSc in hippocampus and cortex was more sialylated than PrPSc from thalamus and stem. Similar trends were also observed in brain materials from RML- and ME7-infected animals. The current study established that PrPSc sialylation status is indeed region-specific. Together with previous studies demonstrating that low sialylation status accelerates prion replication, this work suggests that high vulnerability of certain brain region to prion infection could be attributed to their low sialylation status.
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.M.); (J.C.-Y.C.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jennifer Chen-Yu Chang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.M.); (J.C.-Y.C.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.M.); (J.C.-Y.C.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
- Correspondence:
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18
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Region-specific glial homeostatic signature in prion diseases is replaced by a uniform neuroinflammation signature, common for brain regions and prion strains with different cell tropism. Neurobiol Dis 2020; 137:104783. [PMID: 32001329 DOI: 10.1016/j.nbd.2020.104783] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/21/2020] [Accepted: 01/25/2020] [Indexed: 02/08/2023] Open
Abstract
Chronic neuroinflammation is recognized as a major neuropathological hallmark in a broad spectrum of neurodegenerative diseases including Alzheimer's, Parkinson's, Frontal Temporal Dementia, Amyotrophic Lateral Sclerosis, and prion diseases. Both microglia and astrocytes exhibit region-specific homeostatic transcriptional identities, which under chronic neurodegeneration, transform into reactive phenotypes in a region- and disease-specific manner. Little is known about region-specific identity of glia in prion diseases. The current study was designed to determine whether the region-specific homeostatic signature of glia changes with the progression of prion diseases, and whether these changes occur in a region-dependent or universal manner. Also of interest was whether different prion strains give rise to different reactive phenotypes. To answer these questions, we analyzed gene expression in the thalamus, cortex, hypothalamus and hippocampus of mice infected with 22L and ME7 prion strains using a Nanostring Neuroinflammation panel at the subclinical, early clinical and advanced stages of the disease. We found that at the preclinical stage of the disease, the region-specific homeostatic identities were preserved. However, with the appearance of clinical signs, the region-specific signatures were partially lost and replaced with a neuroinflammation signature. While the same sets of genes were activated by both prion strains, the timing of neuroinflammation and the degree of activation in different brain regions was strain-specific. Changes in astrocyte function scored at the top of the activated pathways. Moreover, clustering analysis suggested that the astrocyte function pathway responded to prion infection prior to the Activated Microglia or Neuron and Neurotransmission pathways. The current work established neuroinflammation gene expression signature associated with prion diseases. Our results illustrate that with the disease progression, the region-specific homeostatic transcriptome signatures are replaced by the region-independent neuroinflammation signature, which is common for prion strains with different cell tropism. The prion-associated neuroinflammation signature identified in the current study overlapped only partially with the microglia degenerative phenotype and the disease-associated microglia phenotype reported for animal models of other neurodegenerative diseases.
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19
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Bradford BM, Mabbott NA. Unaltered intravenous prion disease pathogenesis in the temporary absence of marginal zone B cells. Sci Rep 2019; 9:19119. [PMID: 31836813 PMCID: PMC6910919 DOI: 10.1038/s41598-019-55772-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 12/03/2019] [Indexed: 11/16/2022] Open
Abstract
Prion diseases are a unique, infectious, neurodegenerative disorders that can affect animals and humans. Data from mouse transmissions show that efficient infection of the host after intravenous (IV) prion exposure is dependent upon the early accumulation and amplification of the prions on stromal follicular dendritic cells (FDC) in the B cell follicles. How infectious prions are initially conveyed from the blood-stream to the FDC in the spleen is uncertain. Addressing this issue is important as susceptibility to peripheral prion infections can be reduced by treatments that prevent the early accumulation of prions upon FDC. The marginal zone (MZ) in the spleen contains specialized subsets of B cells and macrophages that are positioned to continuously monitor the blood-stream and remove pathogens, toxins and apoptotic cells. The continual shuttling of MZ B cells between the MZ and the B-cell follicle enables them to efficiently capture and deliver blood-borne antigens and antigen-containing immune complexes to splenic FDC. We tested the hypothesis that MZ B cells also play a role in the initial shuttling of prions from the blood-stream to FDC. MZ B cells were temporarily depleted from the MZ by antibody-mediated blocking of integrin function. We show that depletion of MZ B cells around the time of IV prion exposure did not affect the early accumulation of blood-borne prions upon splenic FDC or reduce susceptibility to IV prion infection. In conclusion, our data suggest that the initial delivery of blood-borne prions to FDC in the spleen occurs independently of MZ B cells.
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Affiliation(s)
- Barry M Bradford
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush, EH25 9RG, UK
| | - Neil A Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush, EH25 9RG, UK.
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20
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Abstract
Prion diseases are rapidly progressive, incurable neurodegenerative disorders caused by misfolded, aggregated proteins known as prions, which are uniquely infectious. Remarkably, these infectious proteins have been responsible for widespread disease epidemics, including kuru in humans, bovine spongiform encephalopathy in cattle, and chronic wasting disease in cervids, the latter of which has spread across North America and recently appeared in Norway and Finland. The hallmark histopathological features include widespread spongiform encephalopathy, neuronal loss, gliosis, and deposits of variably sized aggregated prion protein, ranging from small, soluble oligomers to long, thin, unbranched fibrils, depending on the disease. Here, we explore recent advances in prion disease research, from the function of the cellular prion protein to the dysfunction triggering neurotoxicity, as well as mechanisms underlying prion spread between cells. We also highlight key findings that have revealed new therapeutic targets and consider unanswered questions for future research.
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Affiliation(s)
- Christina J Sigurdson
- Departments of Pathology and Medicine, UC San Diego School of Medicine, University of California, San Diego, La Jolla, California 92093, USA;
| | - Jason C Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska 68178, USA
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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21
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Baskakov IV, Caughey B, Requena JR, Sevillano AM, Surewicz WK, Wille H. The prion 2018 round tables (I): the structure of PrP Sc. Prion 2019; 13:46-52. [PMID: 30646817 PMCID: PMC6422368 DOI: 10.1080/19336896.2019.1569450] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 12/26/2018] [Indexed: 01/26/2023] Open
Abstract
Understanding the structure of PrPSc is without doubt a sine qua non to understand not only PrPSc propagation, but also critical features of that process such as the strain phenomenon and transmission barriers. While elucidation of the PrPSc structure has been full of difficulties, we now have a large amount of structural information that allows us to begin to understand it. This commentary article summarizes a round table that took place within the Prion 2018 meeting held in Santiago de Compostela to discuss the state of the art in this matter. Two alternative models of PrPSc exist: the PIRIBS and the 4-rung β-solenoid models. Both of them have relevant features. The 4-rung β-solenoid model agrees with experimental constraints of brain derived PrPSc obtained from cryo-EM and X-ray fiber diffraction studies. Furthermore, it allows facile accommodation of the bulky glycans that decorate brain-derived PrPSc. On the other hand, the infectious PrP23-144 amyloid exhibits a PIRIBS architecture. Perhaps, both types of structure co-exist.
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Affiliation(s)
- Ilia V. Baskakov
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Byron Caughey
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Jesús R. Requena
- CIMUS Biomedical Research Institute and Department of Medical Sciences, University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
| | - Alejandro M. Sevillano
- Departments of Pathology and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Witold K. Surewicz
- Departments of Pathology, and of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Holger Wille
- Department of Biochemistry and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
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22
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Baskakov IV, Katorcha E, Makarava N. Prion Strain-Specific Structure and Pathology: A View from the Perspective of Glycobiology. Viruses 2018; 10:v10120723. [PMID: 30567302 PMCID: PMC6315442 DOI: 10.3390/v10120723] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/13/2018] [Accepted: 12/15/2018] [Indexed: 01/15/2023] Open
Abstract
Prion diseases display multiple disease phenotypes characterized by diverse clinical symptoms, different brain regions affected by the disease, distinct cell tropism and diverse PrPSc deposition patterns. The diversity of disease phenotypes within the same host is attributed to the ability of PrPC to acquire multiple, alternative, conformationally distinct, self-replicating PrPSc states referred to as prion strains or subtypes. Structural diversity of PrPSc strains has been well documented, yet the question of how different PrPSc structures elicit multiple disease phenotypes remains poorly understood. The current article reviews emerging evidence suggesting that carbohydrates in the form of sialylated N-linked glycans, which are a constitutive part of PrPSc, are important players in defining strain-specific structures and disease phenotypes. This article introduces a new hypothesis, according to which individual strain-specific PrPSc structures govern selection of PrPC sialoglycoforms that form strain-specific patterns of carbohydrate epitopes on PrPSc surface and contribute to defining the disease phenotype and outcomes.
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Affiliation(s)
- Ilia V Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
| | - Elizaveta Katorcha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
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23
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Aguilar‐Calvo P, Bett C, Sevillano AM, Kurt TD, Lawrence J, Soldau K, Hammarström P, Nilsson KPR, Sigurdson CJ. Generation of novel neuroinvasive prions following intravenous challenge. Brain Pathol 2018; 28:999-1011. [PMID: 29505163 PMCID: PMC6123309 DOI: 10.1111/bpa.12598] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 10/08/2018] [Accepted: 02/27/2018] [Indexed: 01/04/2023] Open
Abstract
Prions typically spread into the central nervous system (CNS), likely via peripheral nerves. Yet prion conformers differ in their capacity to penetrate the CNS; certain fibrillar prions replicate persistently in lymphoid tissues with no CNS entry, leading to chronic silent carriers. Subclinical carriers of variant Creutzfeldt-Jakob (vCJD) prions in the United Kingdom have been estimated at 1:2000, and vCJD prions have been transmitted through blood transfusion, however, the circulating prion conformers that neuroinvade remain unclear. Here we investigate how prion conformation impacts brain entry of transfused prions by challenging mice intravenously to subfibrillar and fibrillar strains. We show that most strains infiltrated the brain and caused terminal disease, however, the fibrillar prions showed reduced CNS entry in a strain-dependent manner. Strikingly, the highly fibrillar mCWD prion strain replicated in the spleen and emerged in the brain as a novel strain, indicating that a new neuroinvasive prion had been generated from a previously non-neuroinvasive strain. The new strain showed altered plaque morphology, brain regions targeted and biochemical properties and these properties were maintained upon intracerebral passage. Intracerebral passage of prion-infected spleen re-created the new strain. Splenic prions resembled the new strain biochemically and intracerebral passage of prion-infected spleen re-created the new strain, collectively suggesting splenic prion replication as a potential source. Taken together, these results indicate that intravenous exposure to prion-contaminated blood or blood products may generate novel neuroinvasive prion conformers and disease phenotypes, potentially arising from prion replication in non-neural tissues or from conformer selection.
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Affiliation(s)
| | - Cyrus Bett
- Departments of Pathology and MedicineUC San DiegoLa JollaCA
| | | | | | | | - Katrin Soldau
- Departments of Pathology and MedicineUC San DiegoLa JollaCA
| | - Per Hammarström
- Department of Physics, Chemistry, and BiologyLinköping UniversityLinköpingSweden
| | - K. Peter R. Nilsson
- Department of Physics, Chemistry, and BiologyLinköping UniversityLinköpingSweden
| | - Christina J. Sigurdson
- Departments of Pathology and MedicineUC San DiegoLa JollaCA
- Department of Pathology, Microbiology, and ImmunologyUC DavisDavisCA
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24
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Inflammatory response of microglia to prions is controlled by sialylation of PrP Sc. Sci Rep 2018; 8:11326. [PMID: 30054538 PMCID: PMC6063910 DOI: 10.1038/s41598-018-29720-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/17/2018] [Indexed: 12/22/2022] Open
Abstract
Neuroinflammation is recognized as one of the obligatory pathogenic features of neurodegenerative diseases including Alzheimer’s, Parkinson’s or prion diseases. In prion diseases, space and time correlations between deposition of disease-associated, pathogenic form of the prion protein or PrPSc and microglial-mediated neuroinflammation has been established. Yet, it remains unclear whether activation of microglia is triggered directly by a contact with PrPSc, and what molecular features of PrPSc microglia sense and respond to that drive microglia to inflammatory states. The current study asked the questions whether PrPSc can directly trigger activation of microglia and whether the degree of microglia response depends on the nature of terminal carbohydrate groups on the surface of PrPSc particles. PrPSc was purified from brains of mice infected with mouse-adapted prion strain 22L or neuroblastoma N2a cells stably infected with 22L. BV2 microglial cells or primary microglia were cultured in the presence of purified 22L. We found that exposure of BV2 cells or primary microglia to purified PrPSc triggered proinflammatory responses characterized by an increase in the levels of TNFα, IL6, nitric oxide (NO) and expression of inducible Nitric Oxide Synthase (iNOS). Very similar patterns of inflammatory response were induced by PrPSc purified from mouse brains and neuroblastoma cells arguing that microglia response is independent of the source of PrPSc. To test whether the microglial response is mediated by carbohydrate epitopes on PrPSc surface, the levels of sialylation of PrPSc N-linked glycans was altered by treatment of purified PrPSc with neuraminidase. Partial cleavage of sialic acid residues was found to boost the inflammatory response of microglia to PrPSc. Moreover, transient degradation of Iκβα observed upon treatment with partially desialylated PrPSc suggests that canonical NFκB activation pathway is involved in inflammatory response. The current study is the first to demonstrate that PrPSc can directly trigger inflammatory response in microglia. In addition, this work provides direct evidence that the chemical nature of the carbohydrate groups on PrPSc surface is important for microglial activation.
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25
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Kim S, Han S, Kim T, Nam J, Kim YS, Choi EK, Kim MY. Prolonged follicular helper T cell responses in ME7 scrapie-infected mice. Prion 2018; 12:109-116. [PMID: 29617174 DOI: 10.1080/19336896.2018.1458573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
We previously reported that mice intracerebrally inoculated with the mouse-adapted scrapie strain ME7 have markedly diminished T zones in the spleen due to the decreased expression of CCL19 and CCL21. In addition, follicular dendritic cell networks in germinal centers were larger in ME7-infected spleens compared to uninfected spleens. As an extension of that study, we set out to determine how ME7 infection affects spleen structure and follicular helper T (Tfh) cell responses in mice. For this study, mice were intraperitoneally inoculated with brain homogenate of the ME7 inoculum and spleens were analyzed 50, 130, and 200 days after inoculation and compared with those from uninfected mice. The result showed that ME7- infected mice had increased Tfh cell responses which were maintained until end-stage prion disease. Although CD4 T cells decreased in white pulps, they increased in germinal centers, and expressed higher levels of the Tfh-related genes, such as Bcl6, Il21, Cxcr5, Icos, and Pdcd1. In addition, ME7-infected spleens had increased numbers of CD4 memory T cells. These data indicate that although ME7 infection led to impaired splenic white pulp structure, CD4 memory T cells were increased and Tfh cell responses were required and prolonged to provide help for the replication and accumulation of pathogenic prion protein in germinal centers.
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Affiliation(s)
- Soochan Kim
- a Department of Bioinformatics and Life Science , Soongsil University , Seoul , Korea
| | - Sinsuk Han
- b Department of Biomedical Gerontology , Graduate School of Hallym University , Chuncheon , Korea.,c Ilsong Institute of Life Science, Hallym University , Anyang , Korea
| | - Taehyun Kim
- a Department of Bioinformatics and Life Science , Soongsil University , Seoul , Korea
| | - Jeehoon Nam
- a Department of Bioinformatics and Life Science , Soongsil University , Seoul , Korea
| | - Yong-Sun Kim
- c Ilsong Institute of Life Science, Hallym University , Anyang , Korea.,d Department of Microbiology , College of Medicine, Hallym University , Chuncheon , Korea
| | - Eun-Kyoung Choi
- b Department of Biomedical Gerontology , Graduate School of Hallym University , Chuncheon , Korea.,c Ilsong Institute of Life Science, Hallym University , Anyang , Korea
| | - Mi-Yeon Kim
- a Department of Bioinformatics and Life Science , Soongsil University , Seoul , Korea
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Katorcha E, Baskakov IV. Analysis of Covalent Modifications of Amyloidogenic Proteins Using Two-Dimensional Electrophoresis: Prion Protein and Its Sialylation. Methods Mol Biol 2018; 1779:241-255. [PMID: 29886537 DOI: 10.1007/978-1-4939-7816-8_15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A number of proteins associated with neurodegenerative disease undergo several types of posttranslational modifications. They include N-linked glycosylation of the prion protein and amyloid precursor protein, phosphorylation of tau and α-synuclein. Posttranslational modifications alter physical properties of proteins including their net and surface charges, affecting their processing, life-time and propensity to acquire misfolded, disease-associated states. As such, analysis of posttranslational modifications is important for understanding the mechanisms of pathogenesis. Recent studies documented that sialylation of the disease-associated form of the prion protein or PrPSc controls the fate of prions in an organism and outcomes of prion infection. For assessing sialylation status of PrPSc, we developed a reliable protocol that involves two-dimensional electrophoresis followed by Western blot (2D). The current chapter describes the procedure for the analysis of sialylation status of PrPSc from various sources including central nervous system, secondary lymphoid organs, cultured cells, or PrPSc produced in Protein Misfolding Cyclic Amplification.
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Affiliation(s)
- Elizaveta Katorcha
- Department of Anatomy and Neurobiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ilia V Baskakov
- Department of Anatomy and Neurobiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA.
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27
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Igel-Egalon A, Béringue V, Rezaei H, Sibille P. Prion Strains and Transmission Barrier Phenomena. Pathogens 2018; 7:E5. [PMID: 29301257 PMCID: PMC5874731 DOI: 10.3390/pathogens7010005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/25/2017] [Accepted: 12/26/2017] [Indexed: 11/30/2022] Open
Abstract
Several experimental evidences show that prions are non-conventional pathogens, which physical support consists only in proteins. This finding raised questions regarding the observed prion strain-to-strain variations and the species barrier that happened to be crossed with dramatic consequences on human health and veterinary policies during the last 3 decades. This review presents a focus on a few advances in the field of prion structure and prion strains characterization: from the historical approaches that allowed the concept of prion strains to emerge, to the last results demonstrating that a prion strain may in fact be a combination of a few quasi species with subtle biophysical specificities. Then, we will focus on the current knowledge on the factors that impact species barrier strength and species barrier crossing. Finally, we present probable scenarios on how the interaction of strain properties with host characteristics may account for differential selection of new conformer variants and eventually species barrier crossing.
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Affiliation(s)
- Angélique Igel-Egalon
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, UR892, 78350 Jouy-en-Josas, France.
| | - Vincent Béringue
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, UR892, 78350 Jouy-en-Josas, France.
| | - Human Rezaei
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, UR892, 78350 Jouy-en-Josas, France.
| | - Pierre Sibille
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, UR892, 78350 Jouy-en-Josas, France.
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28
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Mabbott NA. How do PrP Sc Prions Spread between Host Species, and within Hosts? Pathogens 2017; 6:pathogens6040060. [PMID: 29186791 PMCID: PMC5750584 DOI: 10.3390/pathogens6040060] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 11/16/2017] [Accepted: 11/21/2017] [Indexed: 12/22/2022] Open
Abstract
Prion diseases are sub-acute neurodegenerative diseases that affect humans and some domestic and free-ranging animals. Infectious prion agents are considered to comprise solely of abnormally folded isoforms of the cellular prion protein known as PrPSc. Pathology during prion disease is restricted to the central nervous system where it causes extensive neurodegeneration and ultimately leads to the death of the host. The first half of this review provides a thorough account of our understanding of the various ways in which PrPSc prions may spread between individuals within a population, both horizontally and vertically. Many natural prion diseases are acquired peripherally, such as by oral exposure, lesions to skin or mucous membranes, and possibly also via the nasal cavity. Following peripheral exposure, some prions accumulate to high levels within the secondary lymphoid organs as they make their journey from the site of infection to the brain, a process termed neuroinvasion. The replication of PrPSc prions within secondary lymphoid organs is important for their efficient spread to the brain. The second half of this review describes the key tissues, cells and molecules which are involved in the propagation of PrPSc prions from peripheral sites of exposure (such as the lumen of the intestine) to the brain. This section also considers how additional factors such as inflammation and aging might influence prion disease susceptibility.
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Affiliation(s)
- Neil A Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
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29
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Kane SJ, Farley TK, Gordon EO, Estep J, Bender HR, Moreno JA, Bartz J, Telling GC, Pickering MC, Zabel MD. Complement Regulatory Protein Factor H Is a Soluble Prion Receptor That Potentiates Peripheral Prion Pathogenesis. THE JOURNAL OF IMMUNOLOGY 2017; 199:3821-3827. [PMID: 29070671 DOI: 10.4049/jimmunol.1701100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/29/2017] [Indexed: 01/16/2023]
Abstract
Several complement proteins exacerbate prion disease, including C3, C1q, and CD21/35. These proteins of the complement cascade likely increase uptake, trafficking, and retention of prions in the lymphoreticular system, hallmark sites of early prion propagation. Complement regulatory protein factor H (fH) binds modified host proteins and lipids to prevent C3b deposition and, thus, autoimmune cell lysis. Previous reports show that fH binds various conformations of the cellular prion protein, leading us to question the role of fH in prion disease. In this article, we report that transgenic mice lacking Cfh alleles exhibit delayed peripheral prion accumulation, replication, and pathogenesis and onset of terminal disease in a gene-dose manner. We also report a biophysical interaction between purified fH and prion rods enriched from prion-diseased brain. fH also influences prion deposition in brains of infected mice. We conclude from these data and previous findings that the interplay between complement and prions likely involves a complex balance of prion sequestration and destruction via local tissue macrophages, prion trafficking by B and dendritic cells within the lymphoreticular system, intranodal prion replication by B and follicular dendritic cells, and potential prion strain selection by CD21/35 and fH. These findings reveal a novel role for complement-regulatory proteins in prion disease.
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Affiliation(s)
- Sarah J Kane
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Taylor K Farley
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.,National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Elizabeth O Gordon
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Joshua Estep
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Heather R Bender
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Julie A Moreno
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Jason Bartz
- School of Medicine, Creighton University, Omaha, NE 68178; and
| | - Glenn C Telling
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Matthew C Pickering
- Department of Medicine, Centre for Complement and Inflammation Research, Imperial College, London W12 0NN, United Kingdom
| | - Mark D Zabel
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523;
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30
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Katorcha E, Baskakov IV. Analyses of N-linked glycans of PrP Sc revealed predominantly 2,6-linked sialic acid residues. FEBS J 2017; 284:3727-3738. [PMID: 28898525 DOI: 10.1111/febs.14268] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/30/2017] [Accepted: 09/08/2017] [Indexed: 12/19/2022]
Abstract
Mammalian prions (PrPSc ) consist of misfolded, conformationally altered, self-replicating states of the sialoglycoprotein called prion protein or PrPC . Recent studies revealed that the sialylation status of PrPSc plays a major role in evading innate immunity and infecting a host. Establishing the type of linkage by which sialic acid residues are attached to galactose is important, as it helps to identify the sialyltransferases responsible for sialylating PrPC and outline strategies for manipulating the sialyation status of PrPSc . Using enzymatic treatment with sialidases and lectin blots, this study demonstrated that in N-linked glycans of PrPSc , the sialic acid residues are predominantly alpha 2,6-linked. High percentages of alpha 2,6-linked sialic acids were observed in PrPSc of three prion strains 22L, RML, and ME7, as well as PrPSc from brain, spleen, or N2a cells cultured in vitro. Moreover, the variation in the percentage of alpha 2,3- versus 2,6-linked sialic acid was found to be relatively minor between brain-, spleen-, or cell-derived PrPSc , suggesting that the type of linkage is independent of tissue type. Based on the current results, we propose that sialyltransferases of St6Gal family, which is responsible for attaching sialic acids via alpha 2,6-linkages to N-linked glycans, controls sialylation of PrPC and PrPSc .
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Affiliation(s)
- Elizaveta Katorcha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ilia V Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
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31
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Varki A. Are humans prone to autoimmunity? Implications from evolutionary changes in hominin sialic acid biology. J Autoimmun 2017; 83:134-142. [PMID: 28755952 DOI: 10.1016/j.jaut.2017.07.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 07/13/2017] [Accepted: 07/17/2017] [Indexed: 02/06/2023]
Abstract
Given varied intrinsic and extrinsic challenges to the immune system, it is unsurprising that each evolutionary lineage evolves distinctive features of immunoreactivity, and that tolerance mechanisms fail, allowing autoimmunity. Humans appear prone to many autoimmune diseases, with mechanisms both genetic and environmental. Another rapidly evolving biological system involves sialic acids, a family of monosaccharides that are terminal caps on cell surface and secreted molecules of vertebrates, and play multifarious roles in immunity. We have explored multiple genomic changes in sialic acid biology that occurred in human ancestors (hominins), some with implications for enhanced immunoreactivity, and hence for autoimmunity. Human ancestors lost the enzyme synthesizing the common mammalian sialic acid Neu5Gc, with an accumulation of the precursor sialic acid Neu5Ac. Resulting changes include an enhanced reactivity by some immune cells and increased ability of macrophages to kill bacteria, at the cost of increased endotoxin sensitivity. There are also multiple human-specific evolutionary changes in inhibitory and activating Siglecs, immune cell receptors that recognize sialic acids as "self-associated molecular patterns" (SAMPs) to modulate immunity, but can also be hijacked by pathogen molecular mimicry of SAMPs. Altered expression patterns and fixed or polymorphic SIGLEC pseudogenization in humans has modulated both innate and adaptive immunity, sometimes favoring over-reactivity. Meanwhile, dietary intake of Neu5Gc (derived primarily from red meats) allows metabolic incorporation of this non-human molecule into human cells--apparently the first example of "xeno-autoimmunity" involving "xeno-autoantigen" interactions with circulating "xeno-autoantibodies". Taken together, some of these factors may contribute to the apparent human propensity for autoimmunity.
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Affiliation(s)
- Ajit Varki
- Departments of Medicine and Cellular and Molecular Medicine, Glycobiology Research and Training Center (GRTC) and Center for Academic Research and Training in Anthropogeny (CARTA), University of California, San Diego, La Jolla, CA, 92093-0687, USA.
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32
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Shikiya RA, Langenfeld KA, Eckland TE, Trinh J, Holec SAM, Mathiason CK, Kincaid AE, Bartz JC. PrPSc formation and clearance as determinants of prion tropism. PLoS Pathog 2017; 13:e1006298. [PMID: 28355274 PMCID: PMC5386299 DOI: 10.1371/journal.ppat.1006298] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 04/10/2017] [Accepted: 03/16/2017] [Indexed: 11/19/2022] Open
Abstract
Prion strains are characterized by strain-specific differences in neuropathology but can also differ in incubation period, clinical disease, host-range and tissue tropism. The hyper (HY) and drowsy (DY) strains of hamster-adapted transmissible mink encephalopathy (TME) differ in tissue tropism and susceptibility to infection by extraneural routes of infection. Notably, DY TME is not detected in the secondary lymphoreticular system (LRS) tissues of infected hosts regardless of the route of inoculation. We found that similar to the lymphotropic strain HY TME, DY TME crosses mucosal epithelia, enters draining lymphatic vessels in underlying laminae propriae, and is transported to LRS tissues. Since DY TME causes disease once it enters the peripheral nervous system, the restriction in DY TME pathogenesis is due to its inability to establish infection in LRS tissues, not a failure of transport. To determine if LRS tissues can support DY TME formation, we performed protein misfolding cyclic amplification using DY PrPSc as the seed and spleen homogenate as the source of PrPC. We found that the spleen environment can support DY PrPSc formation, although at lower rates compared to lymphotropic strains, suggesting that the failure of DY TME to establish infection in the spleen is not due to the absence of a strain-specific conversion cofactor. Finally, we provide evidence that DY PrPSc is more susceptible to degradation when compared to PrPSc from other lymphotrophic strains. We hypothesize that the relative rates of PrPSc formation and clearance can influence prion tropism.
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Affiliation(s)
- Ronald A. Shikiya
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Katie A. Langenfeld
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Thomas E. Eckland
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Jonathan Trinh
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Sara A. M. Holec
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Candace K. Mathiason
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Anthony E. Kincaid
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
- Department of Pharmacy Science, Creighton University, Omaha, Nebraska, United States of America
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
- * E-mail:
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33
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Baskakov IV. Limited understanding of the functional diversity of N-linked glycans as a major gap of prion biology. Prion 2017; 11:82-88. [PMID: 28324664 PMCID: PMC5399891 DOI: 10.1080/19336896.2017.1301338] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 10/19/2022] Open
Abstract
Among a broad range of hypotheses on the molecular nature of transmissible spongiform encephalopathy or scrapie agents discussed in 1960s was a hypothesis of self-replicating polysaccharides. While the studies of the past 40 years provided unambiguous proof that this is not the case, emerging evidence suggests that carbohydrates in the form of sialylated N-linked glycans, which are a constitutive part of mammalian prions or PrPSc, are essential in determining prion fate in an organism. The current extra-view article discusses recent advancements on the role of N-linked glycans and specifically their sialylation status in controlling prion fate. In addition, this manuscript introduces a new concept on the important role of strain-specific functional carbohydrate epitopes on the PrPSc surface as main determinants of strain-specific biologic features. According to this concept, individual strain-specific folding patterns of PrPSc govern selection of PrPC sialoglycoforms expressed by a host that can be accommodated within particular PrPSc structures. Strain-specific patterns of functional carbohydrate epitopes formed by N-linked glycans on PrPSc surfaces define strain-specific biologic features. As a constitutive part of PrPSc, the individual strain-specific patterns of carbohydrate epitopes propagate faithfully within a given host as long as individual strain-specific PrPSc structures are maintained, ensuring inheritance of strain-specific biologic features.
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Affiliation(s)
- Ilia V. Baskakov
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
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34
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Srivastava S, Katorcha E, Daus ML, Lasch P, Beekes M, Baskakov IV. Sialylation Controls Prion Fate in Vivo. J Biol Chem 2017; 292:2359-2368. [PMID: 27998976 PMCID: PMC5313106 DOI: 10.1074/jbc.m116.768010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/07/2016] [Indexed: 11/06/2022] Open
Abstract
Prions or PrPSc are proteinaceous infectious agents that consist of misfolded, self-replicating states of a sialoglycoprotein called the prion protein or PrPC The current work tests a new hypothesis that sialylation determines the fate of prions in an organism. To begin, we produced control PrPSc from PrPC using protein misfolding cyclic amplification with beads (PMCAb), and also generated PrPSc with reduced sialylation levels using the same method but with partially desialylated PrPC as a substrate (dsPMCAb). Syrian hamsters were inoculated intraperitoneally with brain-derived PrPSc or PrPSc produced in PMCAb or dsPMCAb and then monitored for disease. Animals inoculated with brain- or PMCAb-derived PrPSc developed prion disease, whereas administration of dsPMCAb-derived PrPSc with reduced sialylation did not cause prion disease. Animals inoculated with dsPMCAb-derived material were not subclinical carriers of scrapie, as no PrPSc was detected in brains or spleen of these animals by either Western blotting or after amplification by serial PMCAb. In subsequent experiments, trafficking of brain-, PMCAb-, and dsPMCAb-derived PrPSc to secondary lymphoid organs was monitored in wild type mice. PrPSc sialylation was found to be critical for effective trafficking of PrPSc to secondary lymphoid organs. By 6 hours after inoculation, brain- and PMCAb-derived PrPSc were found in spleen and lymph nodes, whereas dsPMCAb-derived PrPSc was found predominantly in liver. This study demonstrates that the outcome of prion transmission to a wild type host is determined by the sialylation status of the inoculated PrPSc Furthermore, this work suggests that the sialylation status of PrPSc plays an important role in prion lymphotropism.
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Affiliation(s)
- Saurabh Srivastava
- From the Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
| | - Elizaveta Katorcha
- From the Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
| | - Martin L Daus
- the Centre for Biological Threats and Special Pathogens, Robert Koch-Institute, 13353 Berlin, Germany
| | - Peter Lasch
- the Centre for Biological Threats and Special Pathogens, Robert Koch-Institute, 13353 Berlin, Germany
| | - Michael Beekes
- the Centre for Biological Threats and Special Pathogens, Robert Koch-Institute, 13353 Berlin, Germany
| | - Ilia V Baskakov
- From the Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
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35
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Katorcha E, Daus ML, Gonzalez-Montalban N, Makarava N, Lasch P, Beekes M, Baskakov IV. Reversible off and on switching of prion infectivity via removing and reinstalling prion sialylation. Sci Rep 2016; 6:33119. [PMID: 27609323 PMCID: PMC5017131 DOI: 10.1038/srep33119] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/19/2016] [Indexed: 01/14/2023] Open
Abstract
The innate immune system provides the first line of defense against pathogens. To recognize pathogens, this system detects a number of molecular features that discriminate pathogens from host cells, including terminal sialylation of cell surface glycans. Mammalian cell surfaces, but generally not microbial cell surfaces, have sialylated glycans. Prions or PrPSc are proteinaceous pathogens that lack coding nucleic acids but do possess sialylated glycans. We proposed that sialylation of PrPSc is essential for evading innate immunity and infecting a host. In this study, the sialylation status of PrPSc was reduced by replicating PrPSc in serial Protein Misfolding Cyclic Amplification using sialidase-treated PrPC substrate and then restored to original levels by replication using non-treated substrate. Upon intracerebral administration, all animals that received PrPSc with original or restored sialylation levels were infected, whereas none of the animals that received PrPSc with reduced sialylation were infected. Moreover, brains and spleens of animals from the latter group were completely cleared of prions. The current work established that the ability of prions to infect the host via intracerebral administration depends on PrPSc sialylation status. Remarkably, PrPSc infectivity could be switched off and on in a reversible manner by first removing and then restoring PrPSc sialylation.
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Affiliation(s)
- Elizaveta Katorcha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, 21201 United States of America.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, 21201 United States of America
| | - Martin L Daus
- Centre for Biological Threats and Special Pathogens, Robert Koch-Institute, 13353 Berlin, Germany
| | - Nuria Gonzalez-Montalban
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, 21201 United States of America.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, 21201 United States of America
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, 21201 United States of America.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, 21201 United States of America
| | - Peter Lasch
- Centre for Biological Threats and Special Pathogens, Robert Koch-Institute, 13353 Berlin, Germany
| | - Michael Beekes
- Centre for Biological Threats and Special Pathogens, Robert Koch-Institute, 13353 Berlin, Germany
| | - Ilia V Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, 21201 United States of America.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, 21201 United States of America
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36
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Katorcha E, Srivastava S, Klimova N, Baskakov IV. Sialylation of Glycosylphosphatidylinositol (GPI) Anchors of Mammalian Prions Is Regulated in a Host-, Tissue-, and Cell-specific Manner. J Biol Chem 2016; 291:17009-19. [PMID: 27317661 PMCID: PMC5016106 DOI: 10.1074/jbc.m116.732040] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/09/2016] [Indexed: 01/08/2023] Open
Abstract
Prions or PrP(Sc) are proteinaceous infectious agents that consist of misfolded, self-replicating states of the prion protein or PrP(C) PrP(C) is posttranslationally modified with N-linked glycans and a sialylated glycosylphosphatidylinositol (GPI) anchor. Conformational conversion of PrP(C) gives rise to glycosylated and GPI-anchored PrP(Sc) The question of the sialylation status of GPIs within PrP(Sc) has been controversial. Previous studies that examined scrapie brains reported that both sialo- and asialo-GPIs were present in PrP(Sc), with the majority being asialo-GPIs. In contrast, recent work that employed cultured cells claimed that only PrP(C) with sialylo-GPIs could be recruited into PrP(Sc), whereas PrP(C) with asialo-GPIs inhibited conversion. To resolve this controversy, we analyzed the sialylation status of GPIs within PrP(Sc) generated in the brain, spleen, or cultured N2a or C2C12 myotube cells. We found that recruiting PrP(C) with both sialo- and asialo-GPIs is a common feature of PrP(Sc) The mixtures of sialo- and asialo-GPIs were observed in PrP(Sc) universally regardless of prion strain as well as host, tissue, or type of cells that produced PrP(Sc) Remarkably, the proportion of sialo- versus asialo-GPIs was found to be controlled by host, tissue, and cell type but not prion strain. In summary, this study found no strain-specific preferences for selecting PrP(C) with sialo- versus asialo-GPIs. Instead, this work suggests that the sialylation status of GPIs within PrP(Sc) is regulated in a cell-, tissue-, or host-specific manner and is likely to be determined by the specifics of GPI biosynthesis.
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Affiliation(s)
- Elizaveta Katorcha
- From the Center for Biomedical Engineering and Technology and the Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Saurabh Srivastava
- From the Center for Biomedical Engineering and Technology and the Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Nina Klimova
- From the Center for Biomedical Engineering and Technology and the Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Ilia V Baskakov
- From the Center for Biomedical Engineering and Technology and the Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
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Baskakov IV, Katorcha E. Multifaceted Role of Sialylation in Prion Diseases. Front Neurosci 2016; 10:358. [PMID: 27551257 PMCID: PMC4976111 DOI: 10.3389/fnins.2016.00358] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/18/2016] [Indexed: 11/13/2022] Open
Abstract
Mammalian prion or PrP(Sc) is a proteinaceous infectious agent that consists of a misfolded, self-replicating state of a sialoglycoprotein called the prion protein, or PrP(C). Sialylation of the prion protein N-linked glycans was discovered more than 30 years ago, yet the role of sialylation in prion pathogenesis remains poorly understood. Recent years have witnessed extraordinary growth in interest in sialylation and established a critical role for sialic acids in host invasion and host-pathogen interactions. This review article summarizes current knowledge on the role of sialylation of the prion protein in prion diseases. First, we discuss the correlation between sialylation of PrP(Sc) glycans and prion infectivity and describe the factors that control sialylation of PrP(Sc). Second, we explain how glycan sialylation contributes to the prion replication barrier, defines strain-specific glycoform ratios, and imposes constraints for PrP(Sc) structure. Third, several topics, including a possible role for sialylation in animal-to-human prion transmission, prion lymphotropism, toxicity, strain interference, and normal function of PrP(C), are critically reviewed. Finally, a metabolic hypothesis on the role of sialylation in the etiology of sporadic prion diseases is proposed.
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Affiliation(s)
- Ilia V. Baskakov
- Department of Anatomy and Neurobiology, Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimore, MD, USA
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