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VirPorters: Insights into the action of cationic and histidine-rich cell-penetrating peptides. Int J Pharm 2021; 611:121308. [PMID: 34800617 DOI: 10.1016/j.ijpharm.2021.121308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 10/30/2021] [Accepted: 11/15/2021] [Indexed: 11/22/2022]
Abstract
The utilization of nanoparticles for the intracellular delivery of theranostic agents faces one substantial limitation. Sequestration in intracellular vesicles prevents them from reaching the desired location in the cytoplasm or nucleus to deliver their cargo. We investigated whether three different cell-penetrating peptides (CPPs), namely, octa-arginine R8, polyhistidine KH27K and histidine-rich LAH4, could promote cytosolic and/or nuclear transfer of unique model nanoparticles-pseudovirions derived from murine polyomavirus. Two types of CPP-modified pseudovirions that carry the luciferase reporter gene were created: VirPorters-IN with CPPs genetically attached to the capsid interior and VirPorters-EX with CPPs noncovalently associated with the capsid exterior. We tested their transduction ability by luciferase assay and monitored their presence in subcellular fractions. Our results confirmed the overall effect of CPPs on the intracellular destination of the particles and suggested that KH27K has the potential to improve the cytosolic release of pseudovirions. None of the VirPorters caused endomembrane damage detectable by the Galectin-3 assay. Remarkably, a noncovalent modification was required to promote high transduction of the reporter gene and cytosolic delivery of pseudovirions mediated by LAH4. Together, CPPs in different arrangements have demonstrated their potential to improve pseudovirion invasion into cells, and these findings could be useful for the development of other nanoparticle-based delivery systems.
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Lauver MD, Lukacher AE. JCPyV VP1 Mutations in Progressive MultifocalLeukoencephalopathy: Altering Tropismor Mediating Immune Evasion? Viruses 2020; 12:v12101156. [PMID: 33053912 PMCID: PMC7600905 DOI: 10.3390/v12101156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 12/15/2022] Open
Abstract
Polyomaviruses are ubiquitous human pathogens that cause lifelong, asymptomatic infections in healthy individuals. Although these viruses are restrained by an intact immune system, immunocompromised individuals are at risk for developing severe diseases driven by resurgent viral replication. In particular, loss of immune control over JC polyomavirus can lead to the development of the demyelinating brain disease progressive multifocal leukoencephalopathy (PML). Viral isolates from PML patients frequently carry point mutations in the major capsid protein, VP1, which mediates virion binding to cellular glycan receptors. Because polyomaviruses are non-enveloped, VP1 is also the target of the host's neutralizing antibody response. Thus, VP1 mutations could affect tropism and/or recognition by polyomavirus-specific antibodies. How these mutations predispose susceptible individuals to PML and other JCPyV-associated CNS diseases remains to be fully elucidated. Here, we review the current understanding of polyomavirus capsid mutations and their effects on viral tropism, immune evasion, and virulence.
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Lauver MD, Goetschius DJ, Netherby-Winslow CS, Ayers KN, Jin G, Haas DG, Frost EL, Cho SH, Bator CM, Bywaters SM, Christensen ND, Hafenstein SL, Lukacher AE. Antibody escape by polyomavirus capsid mutation facilitates neurovirulence. eLife 2020; 9:e61056. [PMID: 32940605 PMCID: PMC7541085 DOI: 10.7554/elife.61056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/17/2020] [Indexed: 12/27/2022] Open
Abstract
JCPyV polyomavirus, a member of the human virome, causes progressive multifocal leukoencephalopathy (PML), an oft-fatal demyelinating brain disease in individuals receiving immunomodulatory therapies. Mutations in the major viral capsid protein, VP1, are common in JCPyV from PML patients (JCPyV-PML) but whether they confer neurovirulence or escape from virus-neutralizing antibody (nAb) in vivo is unknown. A mouse polyomavirus (MuPyV) with a sequence-equivalent JCPyV-PML VP1 mutation replicated poorly in the kidney, a major reservoir for JCPyV persistence, but retained the CNS infectivity, cell tropism, and neuropathology of the parental virus. This mutation rendered MuPyV resistant to a monoclonal Ab (mAb), whose specificity overlapped the endogenous anti-VP1 response. Using cryo-EM and a custom sub-particle refinement approach, we resolved an MuPyV:Fab complex map to 3.2 Å resolution. The structure revealed the mechanism of mAb evasion. Our findings demonstrate convergence between nAb evasion and CNS neurovirulence in vivo by a frequent JCPyV-PML VP1 mutation.
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Affiliation(s)
- Matthew D Lauver
- Department of Microbiology and Immunology, Penn State College of MedicineHersheyUnited States
| | - Daniel J Goetschius
- Department of Biochemistry and Molecular Biology, Pennsylvania State UniversityUniversity ParkUnited States
| | | | - Katelyn N Ayers
- Department of Microbiology and Immunology, Penn State College of MedicineHersheyUnited States
| | - Ge Jin
- Department of Microbiology and Immunology, Penn State College of MedicineHersheyUnited States
| | - Daniel G Haas
- Department of Microbiology and Immunology, Penn State College of MedicineHersheyUnited States
| | - Elizabeth L Frost
- Department of Microbiology and Immunology, Penn State College of MedicineHersheyUnited States
| | - Sung Hyun Cho
- Huck Institutes of the Life Sciences, Pennsylvania State UniversityUniversity ParkUnited States
| | - Carol M Bator
- Huck Institutes of the Life Sciences, Pennsylvania State UniversityUniversity ParkUnited States
| | - Stephanie M Bywaters
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
| | - Neil D Christensen
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
| | - Susan L Hafenstein
- Department of Biochemistry and Molecular Biology, Pennsylvania State UniversityUniversity ParkUnited States
- Huck Institutes of the Life Sciences, Pennsylvania State UniversityUniversity ParkUnited States
- Department of Medicine, Penn State College of MedicineHersheyUnited States
| | - Aron E Lukacher
- Department of Microbiology and Immunology, Penn State College of MedicineHersheyUnited States
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4
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Influence of cell-penetrating peptides on the activity and stability of virus-based nanoparticles. Int J Pharm 2020; 576:119008. [DOI: 10.1016/j.ijpharm.2019.119008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 12/23/2019] [Accepted: 12/29/2019] [Indexed: 02/06/2023]
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Mesquita I, Estaquier J. Viral Manipulation of the Host Metabolic Network. EXPERIENTIA. SUPPLEMENTUM 2019; 109:377-401. [PMID: 30535606 DOI: 10.1007/978-3-319-74932-7_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Viruses are intracellular parasites that rely on host machinery to replicate and achieve a successful infection. Viruses have evolved to retain a broad range of strategies to manipulate host cell metabolism and metabolic resources, channeling them toward the production of virion components leading to viral production. Although several viruses share similar strategies for manipulating host cell metabolism, these processes depend on several factors, namely, the viral life cycle and the metabolic and energetic status of the infected cell. Based on this knowledge, the development of new therapeutic approaches that circumvent viral spread through the target of altered metabolic pathways is an opportunity to tackle the infection. However, finding effective broad-spectrum strategies that aim at restoring to homeostasis the metabolic alterations induced upon virus infection is still a Holy Grail quest for antiviral therapies. Here, we review the strategies by which viruses manipulate host metabolism for their own benefit, with a particular emphasis on carbohydrate, glutamine, and lipid metabolism.
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Affiliation(s)
- Inês Mesquita
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga, Guimarães, Portugal
| | - Jérôme Estaquier
- Centre de Recherche du CHU de Québec, Université Laval, Québec, Canada. .,CNRS FR 3636, Université Paris Descartes, Paris, France.
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Thompson AJ, de Vries RP, Paulson JC. Virus recognition of glycan receptors. Curr Opin Virol 2019; 34:117-129. [PMID: 30849709 PMCID: PMC6476673 DOI: 10.1016/j.coviro.2019.01.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/24/2019] [Indexed: 01/17/2023]
Abstract
Attachment of viruses to cell-surface receptors is the initial step in infection. Many mammalian viruses have evolved to recognize receptors that are glycans on cell-surface glycoproteins or glycolipids. Although glycans are a ubiquitous component of mammalian cells, the types of terminal structures expressed vary among different cell-types and tissues, and even between comparable cells and tissues from different species, frequently leading to specific tissue and species tropisms as a direct consequence of glycan receptor recognition. Covering the majority of known virus families, this review provides an overview of mammalian viruses that use glycans as receptors, and their roles in determining in host recognition and tropism.
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Affiliation(s)
- Andrew J Thompson
- Departments of Molecular Medicine, Immunology & Microbiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Robert P de Vries
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG, Utrecht, The Netherlands
| | - James C Paulson
- Departments of Molecular Medicine, Immunology & Microbiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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7
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Maginnis MS. Virus-Receptor Interactions: The Key to Cellular Invasion. J Mol Biol 2018; 430:2590-2611. [PMID: 29924965 PMCID: PMC6083867 DOI: 10.1016/j.jmb.2018.06.024] [Citation(s) in RCA: 184] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 06/04/2018] [Accepted: 06/08/2018] [Indexed: 11/05/2022]
Abstract
Virus–receptor interactions play a key regulatory role in viral host range, tissue tropism, and viral pathogenesis. Viruses utilize elegant strategies to attach to one or multiple receptors, overcome the plasma membrane barrier, enter, and access the necessary host cell machinery. The viral attachment protein can be viewed as the “key” that unlocks host cells by interacting with the “lock”—the receptor—on the cell surface, and these lock-and-key interactions are critical for viruses to successfully invade host cells. Many common themes have emerged in virus–receptor utilization within and across virus families demonstrating that viruses often target particular classes of molecules in order to mediate these events. Common viral receptors include sialylated glycans, cell adhesion molecules such as immunoglobulin superfamily members and integrins, and phosphatidylserine receptors. The redundancy in receptor usage suggests that viruses target particular receptors or “common locks” to take advantage of their cellular function and also suggests evolutionary conservation. Due to the importance of initial virus interactions with host cells in viral pathogenesis and the redundancy in viral receptor usage, exploitation of these strategies would be an attractive target for new antiviral therapeutics. Viral receptors are key regulators of host range, tissue tropism, and viral pathogenesis. Many viruses utilize common viral receptors including sialic acid, cell adhesion molecules such as immunoglobulin superfamily members and integrins, and phosphatidylserine receptors. Detailed molecular interactions between viruses and receptors have been defined through elegant biochemical analyses including glycan array screens, structural–functional analyses, and cell-based approaches providing tremendous insights into these initial events in viral infection. Commonalities in virus–receptor interactions present promising targets for the development of broad-spectrum antiviral therapies.
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Affiliation(s)
- Melissa S Maginnis
- Department of Molecular and Biomedical Sciences, The University of Maine, Orono, ME 04469-5735, USA.
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JC Polyomavirus Attachment and Entry: Potential Sites for PML Therapeutics. CURRENT CLINICAL MICROBIOLOGY REPORTS 2017; 4:132-141. [PMID: 28989857 DOI: 10.1007/s40588-017-0069-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE OF REVIEW JC polyomavirus (JCPyV) is a significant human pathogen that causes an asymptomatic infection in the kidney in the majority of the population. In immunosuppressed individuals, the virus can become reactivated and spread to the brain, causing the fatal, demyelinating disease progressive multifocal leukoencephalopathy (PML). There are currently limited treatment options for this fatal disease. Attachment to receptors and entry into host cells are the initiating events in JCPyV infection and therefore an attractive target for therapeutics to prevent or treat PML. This review provides the current understanding of JCPyV attachment and entry events and the potential therapeutics to target these areas. RECENT FINDINGS JCPyV attachment and entry to host cells is mediated by α2,6-linked lactoseries tetrasaccharide c (LSTc) and 5-hydroxytryptamine receptors (5-HT2Rs), respectively, and subsequent trafficking to the endoplasmic reticulum is required for infection. Recently, vaccines, monoclonal antibodies, and small molecules have shown promise as anti-viral and PML therapies. SUMMARY This review summarizes our current understanding of JCPyV attachment, entry, and trafficking and the development of potential PML therapeutics that inhibit these critical steps in JCPyV infection.
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Identification of Rab18 as an Essential Host Factor for BK Polyomavirus Infection Using a Whole-Genome RNA Interference Screen. mSphere 2017; 2:mSphere00291-17. [PMID: 28815213 PMCID: PMC5555678 DOI: 10.1128/mspheredirect.00291-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 07/12/2017] [Indexed: 11/20/2022] Open
Abstract
Polyomaviruses bind to a group of specific gangliosides on the plasma membrane of the cell prior to being endocytosed. They then follow a retrograde trafficking pathway to reach the endoplasmic reticulum (ER). The viruses begin to disassemble in the ER and then exit the ER and move to the nucleus. However, the details of intracellular trafficking between the endosome and the ER are largely unknown. By implementing a whole human genome small interfering RNA screen, we identified Rab18, syntaxin 18, and the NRZ complex as key components in endosome-ER trafficking of the human polyomavirus BKPyV. These results serve to further elucidate the route BKPyV takes from outside the cell to its site of replication in the nucleus. BK polyomavirus (BKPyV) is a human pathogen first isolated in 1971. BKPyV infection is ubiquitous in the human population, with over 80% of adults worldwide being seropositive for BKPyV. BKPyV infection is usually asymptomatic; however, BKPyV reactivation in immunosuppressed transplant patients causes two diseases, polyomavirus-associated nephropathy and hemorrhagic cystitis. To establish a successful infection in host cells, BKPyV must travel in retrograde transport vesicles to reach the nucleus. To make this happen, BKPyV requires the cooperation of host cell proteins. To further identify host factors associated with BKPyV entry and intracellular trafficking, we performed a whole-genome small interfering RNA screen on BKPyV infection of primary human renal proximal tubule epithelial cells. The results revealed the importance of Ras-related protein Rab18 and syntaxin 18 for BKPyV infection. Our subsequent experiments implicated additional factors that interact with this pathway and suggest a more detailed model of the intracellular trafficking process, indicating that BKPyV reaches the endoplasmic reticulum (ER) lumen through a retrograde transport pathway between the late endosome and the ER. IMPORTANCE Polyomaviruses bind to a group of specific gangliosides on the plasma membrane of the cell prior to being endocytosed. They then follow a retrograde trafficking pathway to reach the endoplasmic reticulum (ER). The viruses begin to disassemble in the ER and then exit the ER and move to the nucleus. However, the details of intracellular trafficking between the endosome and the ER are largely unknown. By implementing a whole human genome small interfering RNA screen, we identified Rab18, syntaxin 18, and the NRZ complex as key components in endosome-ER trafficking of the human polyomavirus BKPyV. These results serve to further elucidate the route BKPyV takes from outside the cell to its site of replication in the nucleus.
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Murine Polyomavirus Cell Surface Receptors Activate Distinct Signaling Pathways Required for Infection. mBio 2016; 7:mBio.01836-16. [PMID: 27803182 PMCID: PMC5090042 DOI: 10.1128/mbio.01836-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Virus binding to the cell surface triggers an array of host responses, including activation of specific signaling pathways that facilitate steps in virus entry. Using mouse polyomavirus (MuPyV), we identified host signaling pathways activated upon virus binding to mouse embryonic fibroblasts (MEFs). Pathways activated by MuPyV included the phosphatidylinositol 3-kinase (PI3K), FAK/SRC, and mitogen-activated protein kinase (MAPK) pathways. Gangliosides and α4-integrin are required receptors for MuPyV infection. MuPyV binding to both gangliosides and the α4-integrin receptors was required for activation of the PI3K pathway; however, either receptor interaction alone was sufficient for activation of the MAPK pathway. Using small-molecule inhibitors, we confirmed that the PI3K and FAK/SRC pathways were required for MuPyV infection, while the MAPK pathway was dispensable. Mechanistically, the PI3K pathway was required for MuPyV endocytosis, while the FAK/SRC pathway enabled trafficking of MuPyV along microtubules. Thus, MuPyV interactions with specific cell surface receptors facilitate activation of signaling pathways required for virus entry and trafficking. Understanding how different viruses manipulate cell signaling pathways through interactions with host receptors could lead to the identification of new therapeutic targets for viral infection. Virus binding to cell surface receptors initiates outside-in signaling that leads to virus endocytosis and subsequent virus trafficking. How different viruses manipulate cell signaling through interactions with host receptors remains unclear, and elucidation of the specific receptors and signaling pathways required for virus infection may lead to new therapeutic targets. In this study, we determined that gangliosides and α4-integrin mediate mouse polyomavirus (MuPyV) activation of host signaling pathways. Of these pathways, the PI3K and FAK/SRC pathways were required for MuPyV infection. Both the PI3K and FAK/SRC pathways have been implicated in human diseases, such as heart disease and cancer, and inhibitors directed against these pathways are currently being investigated as therapies. It is possible that these pathways play a role in human PyV infections and could be targeted to inhibit PyV infection in immunosuppressed patients.
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Type I Interferons Regulate the Magnitude and Functionality of Mouse Polyomavirus-Specific CD8 T Cells in a Virus Strain-Dependent Manner. J Virol 2016; 90:5187-99. [PMID: 26984726 DOI: 10.1128/jvi.00199-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 03/10/2016] [Indexed: 01/09/2023] Open
Abstract
UNLABELLED Mouse polyomavirus (MPyV) is a ubiquitous persistent natural mouse pathogen. A glutamic acid (E)-to-glycine (G) difference at position 91 of the VP1 capsid protein shifts the profile of tumors induced by MPyV from an epithelial to a mesenchymal cell origin. Here we asked if this tropism difference affects the MPyV-specific CD8 T cell response, which controls MPyV infection and tumorigenesis. Infection by the laboratory MPyV strain RA (VP1-91G) or a strain A2 mutant with an E-to-G substitution at VP1 residue 91 [A2(91G)] generated a markedly smaller virus-specific CD8 T cell response than that induced by A2(VP1-91E) infection. Mutant A2(91G)-infected mice showed a higher frequency of memory precursor (CD127(hi) KLRG1(lo)) CD8 T cells and a higher recall response than those of A2-infected mice. Using T cell receptor (TCR)-transgenic CD8 T cells and immunization with peptide-pulsed dendritic cells, we found that early bystander inflammation associated with A2 infection contributed to recruitment of the larger MPyV-specific CD8 T cell response. Beta interferon (IFN-β) transcripts were induced early during A2 or A2(91G) infections. IFN-β inhibited replication of A2 and A2(91G) in vitro Using mice lacking IFN-αβ receptors (IFNAR(-/-)), we showed that type I IFNs played a role in controlling MPyV replication in vivo but differentially affected the magnitude and functionality of virus-specific CD8 T cells recruited by A2 and A2(91G) viral infections. These data indicate that type I IFNs are involved in protection against MPyV infection and that their effect on the antiviral CD8 T cell response depends on capsid-mediated tropism properties of the MPyV strain. IMPORTANCE Isolates of the human polyomavirus JC virus from patients with the frequently fatal demyelinating brain disease progressive multifocal leukoencephalopathy (PML) carry single amino acid substitutions in the domain of the VP1 capsid protein that binds the sialic acid moiety of glycoprotein/glycolipid receptors on host cells. These VP1 mutations may alter neural cell tropism or enable escape from neutralizing antibodies. Changes in host cell tropism can affect recruitment of virus-specific CD8 T cells. Using mouse polyomavirus, we demonstrate that a single amino acid difference in VP1 known to shift viral tropism profoundly affects the quantity and quality of the anti-polyomavirus CD8 T cell response and its differentiation into memory cells. These findings raise the possibility that CD8 T cell responses to infections by human polyomaviruses may be influenced by VP1 mutations involving domains that engage host cell receptors.
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You J, O’Hara SD, Velupillai P, Castle S, Levery S, Garcea RL, Benjamin T. Ganglioside and Non-ganglioside Mediated Host Responses to the Mouse Polyomavirus. PLoS Pathog 2015; 11:e1005175. [PMID: 26474471 PMCID: PMC4608836 DOI: 10.1371/journal.ppat.1005175] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 08/28/2015] [Indexed: 11/18/2022] Open
Abstract
Gangliosides serve as receptors for internalization and infection by members of the polyomavirus family. Specificity is determined by recognition of carbohydrate moieties on the ganglioside by the major viral capsid protein VP1. For the mouse polyomavirus (MuPyV), gangliosides with terminal sialic acids in specific linkages are essential. Although many biochemical and cell culture experiments have implicated gangliosides as MuPyV receptions, the role of gangliosides in the MuPyV-infected mouse has not been investigated. Here we report results of studies using ganglioside-deficient mice and derived cell lines. Knockout mice lacking complex gangliosides were completely resistant to the cytolytic and pathogenic effects of the virus. Embryo fibroblasts from these mice were likewise resistant to infection, and supplementation with specific gangliosides restored infectibility. Although lacking receptors for viral infection, cells from ganglioside-deficient mice retained the ability to respond to the virus. Ganglioside-deficient fibroblasts responded rapidly to virus exposure with a transient induction of c-fos as an early manifestation of a mitogenic response. Additionally, splenocytes from ganglioside-deficient mice responded to MuPyV by secretion of IL-12, previously recognized as a key mediator of the innate immune response. Thus, while gangliosides are essential for infection in the animal, gangliosides are not required for mitogenic responses and innate immune responses to the virus. Biological and structural studies have combined to give a detailed understanding of how the mouse polyomavirus binds to sialyloligosaccharides, how polymorphisms in the sialic acid binding pocket of the major virus capsid protein constitute important determinants of pathogenicity, and how gangliosides function as receptors for cell entry and infection by the virus. We used mice with knockouts in defined ganglioside biosynthetic pathways to determine whether gangliosides alone suffice to mediate lethal infection in the intact host and whether non-gangliosides are also recognized by the virus and utilized for important physiological responses. We confirmed the requirement of specific gangliosides for infection and determined that not all gangliosides that bind in vitro serve as receptors in vivo. Results also revealed two physiologically important responses that do not require MuPyV-ganglioside interactions: i) rapid induction of c-fos in fibroblasts as an early step in cell cycle progression on which the virus depends for its own replication, and ii). activation of cytokine secretion by antigen presenting cells as a critical innate immune response to the virus. We infer that these responses are mediated by non-ganglioside receptors bearing sialic acid. These results serve to illustrate the multiplicity of MuPyV receptors and the complexity of virus-cell surface interactions.
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Affiliation(s)
- John You
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Samantha D. O’Hara
- BioFrontiers Institute and the Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Palanivel Velupillai
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sherry Castle
- Department of Chemistry, University of New Hampshire, Durham, New Hampshire, United States of America
| | - Steven Levery
- Department of Chemistry, University of New Hampshire, Durham, New Hampshire, United States of America
| | - Robert L. Garcea
- BioFrontiers Institute and the Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
- * E-mail:
| | - Thomas Benjamin
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
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The Greater Affinity of JC Polyomavirus Capsid for α2,6-Linked Lactoseries Tetrasaccharide c than for Other Sialylated Glycans Is a Major Determinant of Infectivity. J Virol 2015; 89:6364-75. [PMID: 25855729 DOI: 10.1128/jvi.00489-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/30/2015] [Indexed: 01/04/2023] Open
Abstract
UNLABELLED The human JC polyomavirus (JCPyV) establishes an asymptomatic, persistent infection in the kidneys of the majority of the population and is the causative agent of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML) in immunosuppressed individuals. The Mad-1 strain of JCPyV, a brain isolate, was shown earlier to require α2,6-linked sialic acid on the lactoseries tetrasaccharide c (LSTc) glycan for attachment to host cells. In contrast, a JCPyV kidney isolate type 3 strain, WT3, has been reported to interact with sialic acid-containing gangliosides, but the role of these glycans in JCPyV infection has remained unclear. To help rationalize these findings and probe the effects of strain-specific differences on receptor binding, we performed a comprehensive analysis of the glycan receptor specificities of these two representative JCPyV strains using high-resolution X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy, and correlated these data with the results of infectivity assays. We show here that capsid proteins of Mad-1 and WT3 JCPyV can both engage LSTc as well as multiple sialylated gangliosides. However, the binding affinities exhibit subtle differences, with the highest affinity observed for LSTc. Engagement of LSTc is a prerequisite for functional receptor engagement, while the more weakly binding gangliosides are not required for productive infection. Our findings highlight the complexity of virus-carbohydrate interactions and demonstrate that subtle differences in binding affinities, rather than the binding event alone, help determine tissue tropism and viral pathogenesis. IMPORTANCE Viral infection is initiated by attachment to receptors on host cells, and this event plays an important role in viral disease. We investigated the receptor-binding properties of human JC polyomavirus (JCPyV), a virus that resides in the kidneys of the majority of the population and can cause the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML) in the brains of immunosuppressed individuals. JCPyV has been reported to interact with multiple carbohydrate receptors, and we sought to clarify how the interactions between JCPyV and cellular carbohydrate receptors influenced infection. Here we demonstrate that JCPyV can engage numerous sialylated carbohydrate receptors. However, the virus displays preferential binding to LSTc, and only LSTc mediates a productive infection. Our findings demonstrate that subtle differences in binding affinity, rather than receptor engagement alone, are a key determinant of viral infection.
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JC polyomavirus attachment, entry, and trafficking: unlocking the keys to a fatal infection. J Neurovirol 2014; 21:601-13. [PMID: 25078361 DOI: 10.1007/s13365-014-0272-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/05/2014] [Accepted: 06/30/2014] [Indexed: 10/25/2022]
Abstract
The human JC polyomavirus (JCPyV) causes a lifelong persistent infection in the reno-urinary tract in the majority of the adult population worldwide. In healthy individuals, infection is asymptomatic, while in immunocompromised individuals, the virus can spread to the central nervous system and cause a fatal demyelinating disease known as progressive multifocal leukoencephalopathy (PML). There are currently very few treatment options for this rapidly progressing and devastating disease. Understanding the basic biology of JCPyV-host cell interactions is critical for the development of therapeutic strategies to prevent or treat PML. Research in our laboratory has focused on gaining a detailed mechanistic understanding of the initial steps in the JCPyV life cycle in order to define how JCPyV selectively targets cells in the kidney and brain. JCPyV requires sialic acids to attach to host cells and initiate infection, and JCPyV demonstrates specificity for the oligosaccharide lactoseries tetrasaccharide c (LSTc) with an α2,6-linked sialic acid. Following viral attachment, JCPyV entry is facilitated by the 5-hydroxytryptamine (5-HT)2 family of serotonin receptors via clathrin-dependent endocytosis. JCPyV then undergoes retrograde transport to the endoplasmic reticulum (ER) where viral disassembly begins. A novel retrograde transport inhibitor termed Retro-2(cycl) prevents trafficking of JCPyV to the ER and inhibits both initial virus infection and infectious spread in cell culture. Understanding the molecular mechanisms by which JCPyV establishes infection will open up new avenues for the prevention or treatment of virus-induced disease.
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Bilkova E, Forstova J, Abrahamyan L. Coat as a dagger: the use of capsid proteins to perforate membranes during non-enveloped DNA viruses trafficking. Viruses 2014; 6:2899-937. [PMID: 25055856 PMCID: PMC4113798 DOI: 10.3390/v6072899] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 07/09/2014] [Accepted: 07/14/2014] [Indexed: 01/24/2023] Open
Abstract
To get access to the replication site, small non-enveloped DNA viruses have to cross the cell membrane using a limited number of capsid proteins, which also protect the viral genome in the extracellular environment. Most of DNA viruses have to reach the nucleus to replicate. The capsid proteins involved in transmembrane penetration are exposed or released during endosomal trafficking of the virus. Subsequently, the conserved domains of capsid proteins interact with cellular membranes and ensure their efficient permeabilization. This review summarizes our current knowledge concerning the role of capsid proteins of small non-enveloped DNA viruses in intracellular membrane perturbation in the early stages of infection.
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Affiliation(s)
- Eva Bilkova
- Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844, Prague 2, Czech Republic.
| | - Jitka Forstova
- Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844, Prague 2, Czech Republic.
| | - Levon Abrahamyan
- Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844, Prague 2, Czech Republic.
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16
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O'Hara SD, Stehle T, Garcea R. Glycan receptors of the Polyomaviridae: structure, function, and pathogenesis. Curr Opin Virol 2014; 7:73-8. [PMID: 24983512 DOI: 10.1016/j.coviro.2014.05.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 05/27/2014] [Indexed: 11/16/2022]
Abstract
Multiple glycans have been identified as potential cell surface binding motifs for polyomaviruses (PyVs) using both crystallographic structural determinations and in vitro binding assays. However, binding alone does not necessarily imply that a glycan is a functional receptor, and confirmation that specific glycans are important for infection has proved challenging. In vivo analysis of murine polyomavirus (MPyV) infection has shown that subtle alterations in PyV-glycan interactions alone can result in dramatic changes in pathogenicity, implying that similar effects will be found for other PyVs. Our discussion will review the assays used for determining virus-glycan binding, and how these relate to known PyV tropism and pathogenesis.
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Affiliation(s)
- Samantha D O'Hara
- Department of Molecular, Cellular, Developmental Biology, University of Colorado-Boulder, 347 UCB, Boulder, CO 80309, United States; BioFrontiers Institute, University of Colorado-Boulder, 596 UCB, Boulder, CO 80309, United States
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Robert Garcea
- Department of Molecular, Cellular, Developmental Biology, University of Colorado-Boulder, 347 UCB, Boulder, CO 80309, United States; BioFrontiers Institute, University of Colorado-Boulder, 596 UCB, Boulder, CO 80309, United States.
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17
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Involvement of microtubular network and its motors in productive endocytic trafficking of mouse polyomavirus. PLoS One 2014; 9:e96922. [PMID: 24810588 PMCID: PMC4014599 DOI: 10.1371/journal.pone.0096922] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/14/2014] [Indexed: 12/18/2022] Open
Abstract
Infection of non-enveloped polyomaviruses depends on an intact microtubular network. Here we focus on mouse polyomavirus (MPyV). We show that the dynamics of MPyV cytoplasmic transport reflects the characteristics of microtubular motor-driven transport with bi-directional saltatory movements. In cells treated with microtubule-disrupting agents, localization of MPyV was significantly perturbed, the virus was retained at the cell periphery, mostly within membrane structures resembling multicaveolar complexes, and at later times post-infection, only a fraction of the virus was found in Rab7-positive endosomes and multivesicular bodies. Inhibition of cytoplasmic dynein-based motility by overexpression of dynamitin affected perinuclear translocation of the virus, delivery of virions to the ER and substantially reduced the numbers of infected cells, while overexpression of dominant-negative form of kinesin-1 or kinesin-2 had no significant impact on virus localization and infectivity. We also found that transport along microtubules was important for MPyV-containing endosome sequential acquisition of Rab5, Rab7 and Rab11 GTPases. However, in contrast to dominant-negative mutant of Rab7 (T22N), overexpression of dominant-negative mutant Rab11 (S25N) did not affect the virus infectivity. Altogether, our study revealed that MPyV cytoplasmic trafficking leading to productive infection bypasses recycling endosomes, does not require the function of kinesin-1 and kinesin-2, but depends on functional dynein-mediated transport along microtubules for translocation of the virions from peripheral, often caveolin-positive compartments to late endosomes and ER – a prerequisite for efficient delivery of the viral genome to the nucleus.
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18
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Neu U, Allen SAA, Blaum BS, Liu Y, Frank M, Palma AS, Ströh LJ, Feizi T, Peters T, Atwood WJ, Stehle T. A structure-guided mutation in the major capsid protein retargets BK polyomavirus. PLoS Pathog 2013; 9:e1003688. [PMID: 24130487 PMCID: PMC3795024 DOI: 10.1371/journal.ppat.1003688] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/21/2013] [Indexed: 11/19/2022] Open
Abstract
Viruses within a family often vary in their cellular tropism and pathogenicity. In many cases, these variations are due to viruses switching their specificity from one cell surface receptor to another. The structural requirements that underlie such receptor switching are not well understood especially for carbohydrate-binding viruses, as methods capable of structure-specificity studies are only relatively recently being developed for carbohydrates. We have characterized the receptor specificity, structure and infectivity of the human polyomavirus BKPyV, the causative agent of polyomavirus-associated nephropathy, and uncover a molecular switch for binding different carbohydrate receptors. We show that the b-series gangliosides GD3, GD2, GD1b and GT1b all can serve as receptors for BKPyV. The crystal structure of the BKPyV capsid protein VP1 in complex with GD3 reveals contacts with two sialic acid moieties in the receptor, providing a basis for the observed specificity. Comparison with the structure of simian virus 40 (SV40) VP1 bound to ganglioside GM1 identifies the amino acid at position 68 as a determinant of specificity. Mutation of this residue from lysine in BKPyV to serine in SV40 switches the receptor specificity of BKPyV from GD3 to GM1 both in vitro and in cell culture. Our findings highlight the plasticity of viral receptor binding sites and form a template to retarget viruses to different receptors and cell types. Viruses need to bind to receptors on host cells for viral entry and infection, and the type of receptor bound determines the range of hosts and tissues the virus can infect. Viruses within a family often vary in their tissue distribution and pathogenicity because changes in receptor specificity can produce a virus with different spread and infectivity. In fact, many transmissions between species are based on a virus acquiring binding capability for a new receptor. The structural changes that underlie such receptor switching are not well understood. We have analyzed the structural requirements for receptor binding and switching of the human BK polyomavirus (BKPyV), the causative agent of polyomavirus-associated nephropathy. We show that BKPyV uses specific gangliosides that all contain a common α2,8-disialic acid motif to infect cells, and have characterized the interaction in atomic detail. Our data explains the requirement for this disialic acid motif and in particular highlights a single amino acid that is central to determining specificity. Mutation of this residue switches the receptor specificity, enabling BKPyV to infect cells bearing a different class of gangliosides. Our findings highlight the plasticity of viral receptor binding sites and form a template to retarget viruses to different receptors and cell types.
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Affiliation(s)
- Ursula Neu
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Stacy-ann A. Allen
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, United States of America
| | - Bärbel S. Blaum
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
- Department of Chemistry, University of Luebeck, Luebeck, Germany
| | - Yan Liu
- Glycosciences Laboratory, Faculty of Medicine, Imperial College London, London, United Kingdom
| | | | - Angelina S. Palma
- Glycosciences Laboratory, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Luisa J. Ströh
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Ten Feizi
- Glycosciences Laboratory, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Thomas Peters
- Department of Chemistry, University of Luebeck, Luebeck, Germany
| | - Walter J. Atwood
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, United States of America
- * E-mail: (WJA); (TS)
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail: (WJA); (TS)
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Molecular biology, epidemiology, and pathogenesis of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain. Clin Microbiol Rev 2012; 25:471-506. [PMID: 22763635 DOI: 10.1128/cmr.05031-11] [Citation(s) in RCA: 287] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Progressive multifocal leukoencephalopathy (PML) is a debilitating and frequently fatal central nervous system (CNS) demyelinating disease caused by JC virus (JCV), for which there is currently no effective treatment. Lytic infection of oligodendrocytes in the brain leads to their eventual destruction and progressive demyelination, resulting in multiple foci of lesions in the white matter of the brain. Before the mid-1980s, PML was a relatively rare disease, reported to occur primarily in those with underlying neoplastic conditions affecting immune function and, more rarely, in allograft recipients receiving immunosuppressive drugs. However, with the onset of the AIDS pandemic, the incidence of PML has increased dramatically. Approximately 3 to 5% of HIV-infected individuals will develop PML, which is classified as an AIDS-defining illness. In addition, the recent advent of humanized monoclonal antibody therapy for the treatment of autoimmune inflammatory diseases such as multiple sclerosis (MS) and Crohn's disease has also led to an increased risk of PML as a side effect of immunotherapy. Thus, the study of JCV and the elucidation of the underlying causes of PML are important and active areas of research that may lead to new insights into immune function and host antiviral defense, as well as to potential new therapies.
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Cerqueira C, Schelhaas M. Principles of polyoma- and papillomavirus uncoating. Med Microbiol Immunol 2012; 201:427-36. [PMID: 23001401 DOI: 10.1007/s00430-012-0262-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 08/23/2012] [Indexed: 01/09/2023]
Abstract
Virus particles are vehicles for transmission of the viral genetic information between infected and uninfected cells and organisms. They have evolved to self-assemble, to serve as a protective shell for the viral genome during transfer, and to disassemble when entering a target cell. Disassembly during entry is a complex, multi-step process typically termed uncoating. Uncoating is triggered by multiple host-cell interactions. During cell entry, these interactions occur sequentially in different cellular compartments that the viruses pass through on their way to the site of replication. Here, we highlight the general principles of uncoating for two structurally related virus families, the polyoma- and papillomaviruses. Recent research indicates the use of different compartments and cellular interactions for uncoating despite their structural similarity.
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Affiliation(s)
- Carla Cerqueira
- Emmy-Noether Group Virus Endocytosis, Institutes of Molecular Virology and Medical Biochemistry, University of Münster, Münster, Germany
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21
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α2-3- and α2-6- N-linked sialic acids allow efficient interaction of Newcastle Disease Virus with target cells. Glycoconj J 2012; 29:539-49. [PMID: 22869099 PMCID: PMC7088266 DOI: 10.1007/s10719-012-9431-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 06/29/2012] [Accepted: 07/09/2012] [Indexed: 11/10/2022]
Abstract
Receptor recognition and binding is the first step in the viral cycle. It has been established that Newcastle Disease Virus (NDV) interacts with sialylated molecules such as gangliosides and glycoproteins at the cell surface. Nevertheless, the specific receptor(s) that mediate virus entry are not well known. We have analysed the role of the sialic acid linkage in the early steps of the viral infection cycle. Pretreatment of ELL-0 cells with both α2,3 and α2,6 specific sialidases led to the inhibition of NDV binding, fusion and infectivity, which were restored after α2,3(N)- and α2,6(N)-sialyltransferase incubation. Moreover, α2,6(N)-sialyltransferases also restored NDV activities in α2-6-linked sialic acid deficient cells. Competition with α2-6 sialic acid-binding lectins led to a reduction in the three NDV activities (binding, fusion and infectivity) suggesting a role for α2-6- linked sialic acid in NDV entry. We conclude that both α2-3- and α2-6- linked sialic acid containing glycoconjugates may be used for NDV infection. NDV was able to efficiently bind, fuse and infect the ganglioside-deficient cell line GM95 to a similar extent to that of its parental MEB4, suggesting that gangliosides are not essential for NDV binding, fusion and infectivity. Nevertheless, the fact that the interaction of NDV with cells deficient in N-glycoprotein expression such as Lec1 was less efficient prompted us to conclude that NDV requires N-linked glycoproteins for efficient attachment and entry into the host cell.
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22
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Neu U, Hengel H, Blaum BS, Schowalter RM, Macejak D, Gilbert M, Wakarchuk WW, Imamura A, Ando H, Kiso M, Arnberg N, Garcea RL, Peters T, Buck CB, Stehle T. Structures of Merkel cell polyomavirus VP1 complexes define a sialic acid binding site required for infection. PLoS Pathog 2012; 8:e1002738. [PMID: 22910713 PMCID: PMC3406085 DOI: 10.1371/journal.ppat.1002738] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 04/21/2012] [Indexed: 11/18/2022] Open
Abstract
The recently discovered human Merkel cell polyomavirus (MCPyV or MCV) causes the aggressive Merkel cell carcinoma (MCC) in the skin of immunocompromised individuals. Conflicting reports suggest that cellular glycans containing sialic acid (Neu5Ac) may play a role in MCPyV infectious entry. To address this question, we solved X-ray structures of the MCPyV major capsid protein VP1 both alone and in complex with several sialylated oligosaccharides. A shallow binding site on the apical surface of the VP1 capsomer recognizes the disaccharide Neu5Ac-α2,3-Gal through a complex network of interactions. MCPyV engages Neu5Ac in an orientation and with contacts that differ markedly from those observed in other polyomavirus complexes with sialylated receptors. Mutations in the Neu5Ac binding site abolish MCPyV infection, highlighting the relevance of the Neu5Ac interaction for MCPyV entry. Our study thus provides a powerful platform for the development of MCPyV-specific vaccines and antivirals. Interestingly, engagement of sialic acid does not interfere with initial attachment of MCPyV to cells, consistent with a previous proposal that attachment is mediated by a class of non-sialylated carbohydrates called glycosaminoglycans. Our results therefore suggest a model in which sialylated glycans serve as secondary, post-attachment co-receptors during MCPyV infectious entry. Since cell-surface glycans typically serve as primary attachment receptors for many viruses, we identify here a new role for glycans in mediating, and perhaps even modulating, post-attachment entry processes.
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Affiliation(s)
- Ursula Neu
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
| | - Holger Hengel
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
| | - Bärbel S. Blaum
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
- Department of Chemistry, University of Luebeck, Luebeck, Germany
| | - Rachel M. Schowalter
- Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Dennis Macejak
- Department of Molecular, Cellular, and Developmental Biology, and the Biofrontiers Institute, University of Colorado at Boulder, Boulder, Colorado, United States of America
| | - Michel Gilbert
- National Research Council Canada, Institute for Biological Sciences, Glycobiology Program, Ottawa, Ontario, Canada
| | - Warren W. Wakarchuk
- National Research Council Canada, Institute for Biological Sciences, Glycobiology Program, Ottawa, Ontario, Canada
| | - Akihiro Imamura
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto, Japan
- Department of Applied Bioorganic Chemistry, Gifu University, Gifu, Japan
| | - Hiromune Ando
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto, Japan
- Department of Applied Bioorganic Chemistry, Gifu University, Gifu, Japan
| | - Makoto Kiso
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto, Japan
- Department of Applied Bioorganic Chemistry, Gifu University, Gifu, Japan
| | - Niklas Arnberg
- Division of Virology, Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Robert L. Garcea
- Department of Molecular, Cellular, and Developmental Biology, and the Biofrontiers Institute, University of Colorado at Boulder, Boulder, Colorado, United States of America
| | - Thomas Peters
- Department of Chemistry, University of Luebeck, Luebeck, Germany
| | - Christopher B. Buck
- Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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23
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Inoue T, Tsai B. A large and intact viral particle penetrates the endoplasmic reticulum membrane to reach the cytosol. PLoS Pathog 2011; 7:e1002037. [PMID: 21589906 PMCID: PMC3093372 DOI: 10.1371/journal.ppat.1002037] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2010] [Accepted: 03/07/2011] [Indexed: 11/18/2022] Open
Abstract
Non-enveloped viruses penetrate host membranes to infect cells. A cell-based assay was used to probe the endoplasmic reticulum (ER)-to-cytosol membrane transport of the non-enveloped SV40. We found that, upon ER arrival, SV40 is released into the lumen and undergoes sequential disulfide bond disruptions to reach the cytosol. However, despite these ER-dependent conformational changes, SV40 crosses the ER membrane as a large and intact particle consisting of the VP1 coat, the internal components VP2, VP3, and the genome. This large particle subsequently disassembles in the cytosol. Mutant virus and inhibitor studies demonstrate VP3 and likely the viral genome, as well as cellular proteasome, control ER-to-cytosol transport. Our results identify the sequence of events, as well as virus and host components, that regulate ER membrane penetration. They also suggest that the ER membrane supports passage of a large particle, potentially through either a sizeable protein-conducting channel or the lipid bilayer. Biological membranes represent a major barrier during viral infection. While the mechanism by which an enveloped virus breaches the limiting membrane of a host cell is well-characterized, this membrane penetration process is poorly understood for non-enveloped viruses. Indeed, most available insights on membrane transport of non-enveloped viruses are built upon in vitro studies. Here we established a cell-based assay to elucidate the molecular mechanism by which the non-enveloped SV40 penetrates the endoplasmic reticulum (ER) membrane to access the cytosol, a critical step in infection. Strikingly, we uncovered SV40 breaches the ER membrane as a large and intact viral particle, despite the conformational changes it experiences in the ER lumen. This result suggests that the ER membrane can accommodate translocation of a large protein complex, possibly through either a sizeable protein channel or the ER membrane bilayer. In addition to this finding, we also pinpoint viral and host components that control the ER-to-cytosol membrane transport event. Together, our data illuminate the cellular mechanism by which a non-enveloped virus penetrates the limiting membrane of a target cell during infection.
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Affiliation(s)
- Takamasa Inoue
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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24
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Bradbury FA, Tsai B. Functional versus decoy receptor-regulated entry of polyomaviruses. Future Virol 2011. [DOI: 10.2217/fvl.10.71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Faye A Bradbury
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Room 3043, Ann Arbor, MI 48109, USA
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