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Chaikeeratisak V, Khanna K, Nguyen KT, Egan ME, Enustun E, Armbruster E, Lee J, Pogliano K, Villa E, Pogliano J. Subcellular organization of viral particles during maturation of nucleus-forming jumbo phage. SCIENCE ADVANCES 2022; 8:eabj9670. [PMID: 35507660 PMCID: PMC9067925 DOI: 10.1126/sciadv.abj9670] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 03/16/2022] [Indexed: 06/03/2023]
Abstract
Many eukaryotic viruses assemble mature particles within distinct subcellular compartments, but bacteriophages are generally assumed to assemble randomly throughout the host cell cytoplasm. Here, we show that viral particles of Pseudomonas nucleus-forming jumbo phage PhiPA3 assemble into a unique structure inside cells we term phage bouquets. We show that after capsids complete DNA packaging at the surface of the phage nucleus, tails assemble and attach to capsids, and these particles accumulate over time in a spherical pattern, with tails oriented inward and the heads outward to form bouquets at specific subcellular locations. Bouquets localize at the same fixed distance from the phage nucleus even when it is mispositioned, suggesting an active mechanism for positioning. These results mark the discovery of a pathway for organizing mature viral particles inside bacteria and demonstrate that nucleus-forming jumbo phages, like most eukaryotic viruses, are highly spatially organized during all stages of their lytic cycle.
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Affiliation(s)
- Vorrapon Chaikeeratisak
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Kanika Khanna
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Katrina T Nguyen
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - MacKennon E Egan
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Eray Enustun
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emily Armbruster
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jina Lee
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kit Pogliano
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Elizabeth Villa
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Joe Pogliano
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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2
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Yang JE, Rossignol ED, Chang D, Zaia J, Forrester I, Raja K, Winbigler H, Nicastro D, Jackson WT, Bullitt E. Complexity and ultrastructure of infectious extracellular vesicles from cells infected by non-enveloped virus. Sci Rep 2020; 10:7939. [PMID: 32409751 PMCID: PMC7224179 DOI: 10.1038/s41598-020-64531-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 04/15/2020] [Indexed: 02/07/2023] Open
Abstract
Enteroviruses support cell-to-cell viral transmission prior to their canonical lytic spread of virus. Poliovirus (PV), a prototype for human pathogenic positive-sense RNA enteroviruses, and picornaviruses in general, transport multiple virions en bloc via infectious extracellular vesicles, 100~1000 nm in diameter, secreted from host cells. Using biochemical and biophysical methods we identify multiple components in secreted microvesicles, including mature PV virions; positive-sense genomic and negative-sense replicative, template viral RNA; essential viral replication proteins; and cellular proteins. Using cryo-electron tomography, we visualize the near-native three-dimensional architecture of secreted infectious microvesicles containing both virions and a unique morphological component that we describe as a mat-like structure. While the composition of these mat-like structures is not yet known, based on our biochemical data they are expected to be comprised of unencapsidated RNA and proteins. In addition to infectious microvesicles, CD9-positive exosomes released from PV-infected cells are also infectious and transport virions. Thus, our data show that, prior to cell lysis, non-enveloped viruses are secreted within infectious vesicles that also transport viral unencapsidated RNAs, viral and host proteins. Understanding the structure and function of these infectious particles helps elucidate the mechanism by which extracellular vesicles contribute to the spread of non-enveloped virus infection.
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Affiliation(s)
- Jie E Yang
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States.,Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, United States
| | - Evan D Rossignol
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States.,Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, 02139, United States
| | - Deborah Chang
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, United States
| | - Joseph Zaia
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, United States
| | - Isaac Forrester
- Department of Biochemistry, Baylor College of Medicine, Houston, United States
| | - Kiran Raja
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Holly Winbigler
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 20201, United States
| | - Daniela Nicastro
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75235, United States
| | - William T Jackson
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 20201, United States
| | - Esther Bullitt
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States.
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3
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Liu SL, Wang ZG, Xie HY, Liu AA, Lamb DC, Pang DW. Single-Virus Tracking: From Imaging Methodologies to Virological Applications. Chem Rev 2020; 120:1936-1979. [PMID: 31951121 PMCID: PMC7075663 DOI: 10.1021/acs.chemrev.9b00692] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
Uncovering
the mechanisms of virus infection and assembly is crucial
for preventing the spread of viruses and treating viral disease. The
technique of single-virus tracking (SVT), also known as single-virus
tracing, allows one to follow individual viruses at different parts
of their life cycle and thereby provides dynamic insights into fundamental
processes of viruses occurring in live cells. SVT is typically based
on fluorescence imaging and reveals insights into previously unreported
infection mechanisms. In this review article, we provide the readers
a broad overview of the SVT technique. We first summarize recent advances
in SVT, from the choice of fluorescent labels and labeling strategies
to imaging implementation and analytical methodologies. We then describe
representative applications in detail to elucidate how SVT serves
as a valuable tool in virological research. Finally, we present our
perspectives regarding the future possibilities and challenges of
SVT.
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Affiliation(s)
- Shu-Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine , Nankai University , Tianjin 300071 , P. R. China.,Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry , China University of Geosciences , Wuhan 430074 , P. R. China
| | - Zhi-Gang Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine , Nankai University , Tianjin 300071 , P. R. China
| | - Hai-Yan Xie
- School of Life Science , Beijing Institute of Technology , Beijing 100081 , P. R. China
| | - An-An Liu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine , Nankai University , Tianjin 300071 , P. R. China
| | - Don C Lamb
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), and Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM) , Ludwig-Maximilians-Universität , München , 81377 , Germany
| | - Dai-Wen Pang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine , Nankai University , Tianjin 300071 , P. R. China.,College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology , Wuhan University , Wuhan 430072 , P. R. China
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4
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Nathan L, Daniel S. Single Virion Tracking Microscopy for the Study of Virus Entry Processes in Live Cells and Biomimetic Platforms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1215:13-43. [PMID: 31317494 PMCID: PMC7122913 DOI: 10.1007/978-3-030-14741-9_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The most widely-used assays for studying viral entry, including infectivity, cofloatation, and cell-cell fusion assays, yield functional information but provide low resolution of individual entry steps. Structural characterization provides high-resolution conformational information, but on its own is unable to address the functional significance of these conformations. Single virion tracking microscopy techniques provide more detail on the intermediate entry steps than infection assays and more functional information than structural methods, bridging the gap between these methods. In addition, single virion approaches also provide dynamic information about the kinetics of entry processes. This chapter reviews single virion tracking techniques and describes how they can be applied to study specific virus entry steps. These techniques provide information complementary to traditional ensemble approaches. Single virion techniques may either probe virion behavior in live cells or in biomimetic platforms. Synthesizing information from ensemble, structural, and single virion techniques ultimately yields a more complete understanding of the viral entry process than can be achieved by any single method alone.
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Affiliation(s)
- Lakshmi Nathan
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA.
| | - Susan Daniel
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA.
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Walsh D, Naghavi MH. Exploitation of Cytoskeletal Networks during Early Viral Infection. Trends Microbiol 2018; 27:39-50. [PMID: 30033343 DOI: 10.1016/j.tim.2018.06.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/12/2018] [Accepted: 06/29/2018] [Indexed: 12/12/2022]
Abstract
Being dependent upon host transport systems to navigate the cytoplasm, viruses have evolved various strategies to manipulate cytoskeletal functions. Generally, viruses use the actin cytoskeleton to control entry and short-range transport at the cell periphery and exploit microtubules (MTs) for longer-range cytosolic transport, in some cases to reach the nucleus. While earlier studies established the fundamental importance of these networks to successful infection, the mechanistic details and true extent to which viruses usurp highly specialized host cytoskeletal regulators and motor adaptors is only beginning to emerge. This review outlines our current understanding of how cytoskeletal regulation contributes specifically to the early stages of viral infection, with a primary focus on retroviruses and herpesviruses as examples of recent advances in this area.
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Affiliation(s)
- Derek Walsh
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Mojgan H Naghavi
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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6
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Imaging, Tracking and Computational Analyses of Virus Entry and Egress with the Cytoskeleton. Viruses 2018; 10:v10040166. [PMID: 29614729 PMCID: PMC5923460 DOI: 10.3390/v10040166] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 12/27/2022] Open
Abstract
Viruses have a dual nature: particles are “passive substances” lacking chemical energy transformation, whereas infected cells are “active substances” turning-over energy. How passive viral substances convert to active substances, comprising viral replication and assembly compartments has been of intense interest to virologists, cell and molecular biologists and immunologists. Infection starts with virus entry into a susceptible cell and delivers the viral genome to the replication site. This is a multi-step process, and involves the cytoskeleton and associated motor proteins. Likewise, the egress of progeny virus particles from the replication site to the extracellular space is enhanced by the cytoskeleton and associated motor proteins. This overcomes the limitation of thermal diffusion, and transports virions and virion components, often in association with cellular organelles. This review explores how the analysis of viral trajectories informs about mechanisms of infection. We discuss the methodology enabling researchers to visualize single virions in cells by fluorescence imaging and tracking. Virus visualization and tracking are increasingly enhanced by computational analyses of virus trajectories as well as in silico modeling. Combined approaches reveal previously unrecognized features of virus-infected cells. Using select examples of complementary methodology, we highlight the role of actin filaments and microtubules, and their associated motors in virus infections. In-depth studies of single virion dynamics at high temporal and spatial resolutions thereby provide deep insight into virus infection processes, and are a basis for uncovering underlying mechanisms of how cells function.
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7
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Liu P, Weinreb V, Ridilla M, Betts L, Patel P, de Silva AM, Thompson NL, Jacobson K. Rapid, directed transport of DC-SIGN clusters in the plasma membrane. SCIENCE ADVANCES 2017; 3:eaao1616. [PMID: 29134199 PMCID: PMC5677337 DOI: 10.1126/sciadv.aao1616] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/16/2017] [Indexed: 05/12/2023]
Abstract
C-type lectins, including dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), are all-purpose pathogen receptors that exist in nanoclusters in plasma membranes of dendritic cells. A small fraction of these clusters, obvious from the videos, can undergo rapid, directed transport in the plane of the plasma membrane at average speeds of more than 1 μm/s in both dendritic cells and MX DC-SIGN murine fibroblasts ectopically expressing DC-SIGN. Surprisingly, instantaneous speeds can be considerably greater. In MX DC-SIGN cells, many cluster trajectories are colinear with microtubules that reside close to the ventral membrane, and the microtubule-depolymerizing drug, nocodazole, markedly reduced the areal density of directed movement trajectories, suggesting a microtubule motor-driven transport mechanism; by contrast, latrunculin A, which affects the actin network, did not depress this movement. Rapid, retrograde movement of DC-SIGN may be an efficient mechanism for bringing bound pathogen on the leading edge and projections of dendritic cells to the perinuclear region for internalization and processing. Dengue virus bound to DC-SIGN on dendritic projections was rapidly transported toward the cell center. The existence of this movement within the plasma membrane points to an unexpected lateral transport mechanism in mammalian cells and challenges our current concepts of cortex-membrane interactions.
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Affiliation(s)
- Ping Liu
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Violetta Weinreb
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Marc Ridilla
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laurie Betts
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pratik Patel
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Aravinda M. de Silva
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nancy L. Thompson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ken Jacobson
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Corresponding author.
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8
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Li Q, Li W, Yin W, Guo J, Zhang ZP, Zeng D, Zhang X, Wu Y, Zhang XE, Cui Z. Single-Particle Tracking of Human Immunodeficiency Virus Type 1 Productive Entry into Human Primary Macrophages. ACS NANO 2017; 11:3890-3903. [PMID: 28371581 DOI: 10.1021/acsnano.7b00275] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Macrophages are one of the major targets of human immunodeficiency virus (HIV-1), but the viral entry pathway remains poorly understood in these cells. Noninvasive virus labeling and single-virus tracking are effective tools for studying virus entry. Here, we constructed a quantum dot (QD)-encapsulated infectious HIV-1 particle to track viral entry at a single-particle level in live human primary macrophages. QDs were encapsulated in HIV-1 virions by incorporating viral accessory protein Vpr-conjugated QDs during virus assembly. With the HIV-1 particles encapsulating QDs, we monitored the early phase of viral infection in real time and observed that, during infection, HIV-1 was endocytosed in a clathrin-mediated manner; the particles were translocated into Rab5A-positive endosomes, and the core was released into the cytoplasm by viral envelope-mediated endosomal fusion. Drug inhibition assays verified that endosome fusion contributes to HIV-1 productive infection in primary macrophages. Additionally, we observed that a dynamic actin cytoskeleton is critical for HIV-1 entry and intracellular migration in primary macrophages. HIV-1 dynamics and infection could be blocked by multiple different actin inhibitors. Our study revealed a productive entry pathway in macrophages that requires both endosomal function and actin dynamics, which may assist in the development of inhibitors to block the HIV entry in macrophages.
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Affiliation(s)
- Qin Li
- College of Life Science and Technology, Huazhong University of Science and Technology , Wuhan 430074, P.R. China
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences , Wuhan 430071, P.R. China
| | - Wei Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences , Wuhan 430071, P.R. China
| | - Wen Yin
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences , Wuhan 430071, P.R. China
| | - Jia Guo
- National Center for Biodefense and Infectious Diseases, Department of Molecular and Microbiology, George Mason University , Manassas, Virginia 20110, United States
| | - Zhi-Ping Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences , Wuhan 430071, P.R. China
| | - Dejun Zeng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences , Wuhan 430071, P.R. China
| | - Xiaowei Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences , Wuhan 430071, P.R. China
| | - Yuntao Wu
- National Center for Biodefense and Infectious Diseases, Department of Molecular and Microbiology, George Mason University , Manassas, Virginia 20110, United States
| | - Xian-En Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences , Beijing 100101, P.R. China
| | - Zongqiang Cui
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences , Wuhan 430071, P.R. China
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9
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Shahriari S, Gordon J, Ghildyal R. Host cytoskeleton in respiratory syncytial virus assembly and budding. Virol J 2016; 13:161. [PMID: 27670781 PMCID: PMC5037899 DOI: 10.1186/s12985-016-0618-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/17/2016] [Indexed: 12/02/2022] Open
Abstract
Respiratory syncytial virus (RSV) is one of the major pathogens responsible for lower respiratory tract infections (LRTI) in young children, the elderly, and the immunosuppressed. Currently, there are no antiviral drugs or vaccines available that effectively target RSV infections, proving a significant challenge in regards to prevention and treatment. An in-depth understanding of the host-virus interactions that underlie assembly and budding would inform new targets for antiviral development.Current research suggests that the polymerised form of actin, the filamentous or F-actin, plays a role in RSV assembly and budding. Treatment with cytochalasin D, which disrupts F-actin, has been shown to inhibit virus release. In addition, the actin cytoskeleton has been shown to interact with the RSV matrix (M) protein, which plays a central role in RSV assembly. For this reason, the interaction between these two components is hypothesised to facilitate the movement of viral components in the cytoplasm and to the budding site. Despite increases in our knowledge of RSV assembly and budding, M-actin interactions are not well understood. In this review, we discuss the current literature on the role of actin cytoskeleton during assembly and budding of RSV with the aim to integrate disparate studies to build a hypothetical model of the various molecular interactions between actin and RSV M protein that facilitate RSV assembly and budding.
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Affiliation(s)
- Shadi Shahriari
- Respiratory Virology Group, Health Research Institute, Faculty of Education, Science, Technology and Mathematics, University of Canberra, Canberra, 2617, Australia
| | - James Gordon
- Respiratory Virology Group, Health Research Institute, Faculty of Education, Science, Technology and Mathematics, University of Canberra, Canberra, 2617, Australia
| | - Reena Ghildyal
- Respiratory Virology Group, Health Research Institute, Faculty of Education, Science, Technology and Mathematics, University of Canberra, Canberra, 2617, Australia.
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Blaas D. Viral entry pathways: the example of common cold viruses. Wien Med Wochenschr 2016; 166:211-26. [PMID: 27174165 PMCID: PMC4871925 DOI: 10.1007/s10354-016-0461-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 04/12/2016] [Indexed: 02/02/2023]
Abstract
For infection, viruses deliver their genomes into the host cell. These nucleic acids are usually tightly packed within the viral capsid, which, in turn, is often further enveloped within a lipid membrane. Both protect them against the hostile environment. Proteins and/or lipids on the viral particle promote attachment to the cell surface and internalization. They are likewise often involved in release of the genome inside the cell for its use as a blueprint for production of new viruses. In the following, I shall cursorily discuss the early more general steps of viral infection that include receptor recognition, uptake into the cell, and uncoating of the viral genome. The later sections will concentrate on human rhinoviruses, the main cause of the common cold, with respect to the above processes. Much of what is known on the underlying mechanisms has been worked out by Renate Fuchs at the Medical University of Vienna.
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Affiliation(s)
- Dieter Blaas
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter, Dr. Bohr Gasse 9/3, 1030, Vienna, Austria.
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11
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Chan SY, Sam IC, Lai JK, Chan YF. Cellular proteome alterations in response to enterovirus 71 and coxsackievirus A16 infections in neuronal and intestinal cell lines. J Proteomics 2015; 125:121-30. [DOI: 10.1016/j.jprot.2015.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/21/2015] [Accepted: 05/13/2015] [Indexed: 12/14/2022]
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12
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Yu X, Xu F, Ramirez NGP, Kijewski SDG, Akiyama H, Gummuluru S, Reinhard BM. Dressing up Nanoparticles: A Membrane Wrap to Induce Formation of the Virological Synapse. ACS NANO 2015; 9:4182-92. [PMID: 25853367 PMCID: PMC4423798 DOI: 10.1021/acsnano.5b00415] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Next-generation nanoparticle-based drug delivery systems require the ability to target specific organelles or subcellular regions in selected target cells. Human immunodeficiency virus type I (HIV-1) particles are evolutionarily optimized nanocarriers that have evolved to avoid intracellular degradation and achieve enrichment at the synapse between mature dendritic cells (mDCs) and T cells by subverting cellular trafficking mechanisms. This study demonstrates that integration of the glycosphingolipid, GM3, in a membrane around a solid nanoparticle (NP) core is sufficient to recapitulate key aspects of the virus particle trafficking in mDCs. GM3-presenting artificial virus NPs (GM3-AVNs) accumulate in CD169(+) and CD81(+) nonlysosomal compartments in an actin-dependent process that mimics the sequestration of HIV-1. Live-cell optical tracking studies reveal a preferential recruitment and arrest of surface scanning CD4(+) T cells in direct vicinity to the AVN-enriched compartments. The formed mDC-T cell conjugates exhibit strong morphological similarities between the GM3-AVN-containing mDC-T cell synapse and the HIV-1 virological synapse, indicating that GM3-CD169 interactions alone are sufficient for establishing the mDC-T cell virological synapse. These results emphasize the potential of the GM3-AVN approach for providing therapeutic access to a key step of the host immune response--formation of the synaptic junction between an antigen-presenting cell (mDC) and T cells--for modulating and controlling immune responses.
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Affiliation(s)
- Xinwei Yu
- Department of Chemistry and The Photonics Center, Boston University, Boston, MA 02215, United States
| | - Fangda Xu
- Department of Chemistry and The Photonics Center, Boston University, Boston, MA 02215, United States
| | | | - Suzanne D. G. Kijewski
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, United States
| | - Hisashi Akiyama
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, United States
| | - Suryaram Gummuluru
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, United States
| | - Björn M. Reinhard
- Department of Chemistry and The Photonics Center, Boston University, Boston, MA 02215, United States
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13
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Zhao S, Gao J, Zhu L, Yang Q. Transmissible gastroenteritis virus and porcine epidemic diarrhoea virus infection induces dramatic changes in the tight junctions and microfilaments of polarized IPEC-J2 cells. Virus Res 2014; 192:34-45. [PMID: 25173696 PMCID: PMC7114495 DOI: 10.1016/j.virusres.2014.08.014] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 08/15/2014] [Accepted: 08/19/2014] [Indexed: 12/12/2022]
Abstract
Viral infection converts the normal constitution of a cell to optimise viral entry, replication, and virion production. These conversions contain alterations or disruptions of the tight and adherens junctions between cells as part of their pathogenesis, and reorganise cellular microfilaments that initiate, sustain and spread the viral infections and so on. Using porcine epidemic diarrhoea virus (PEDV), transmissible gastroenteritis virus (TGEV) and a model of normal intestinal epithelial cells (IPEC-J2), we researched the interaction between tight and adherens junctions and microfilaments of IPEC-J2 cells with these viruses. In our work, the results showed that IPEC-J2 cells were susceptible to TGEV and PEDV infection. And TGEV could impair the barrier integrity of IPEC-J2 cells at early stages of infection through down-regulating some proteins of tight and adherens junctions, while PEDV cloud cause a slight of damage in the integrity of epithelial barrier. In addition, they also could affect the microfilaments remodelling of IPEC-J2 cells, and the drug-interfered microfilaments could inhibit viral replication and release. Furthermore, PEDV+TGEV co-infection was more aggravating to damage of tight junctions and remodelling of microfilaments than their single infection. Finally, the PEDV and TGEV infection affected the MAPK pathway, and inhibition of MAPK pathway regulated the changes of tight junctions and microfilaments of cells. These studies provide a new insight from the perspective of the epithelial barrier and microfilaments into the pathogenesis of PEDV and TGEV.
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Affiliation(s)
- Shanshan Zhao
- Key Lab of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Wei gang 1, Jiangsu, PR China
| | - Junkai Gao
- Key Lab of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Wei gang 1, Jiangsu, PR China
| | - Liqi Zhu
- Key Lab of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Wei gang 1, Jiangsu, PR China
| | - Qian Yang
- Key Lab of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Wei gang 1, Jiangsu, PR China.
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Transmissible gastroenteritis virus and porcine epidemic diarrhoea virus infection induces dramatic changes in the tight junctions and microfilaments of polarized IPEC-J2 cells. Virus Res 2014. [PMID: 25173696 DOI: 10.1016/j.virusres.2014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Viral infection converts the normal constitution of a cell to optimise viral entry, replication, and virion production. These conversions contain alterations or disruptions of the tight and adherens junctions between cells as part of their pathogenesis, and reorganise cellular microfilaments that initiate, sustain and spread the viral infections and so on. Using porcine epidemic diarrhoea virus (PEDV), transmissible gastroenteritis virus (TGEV) and a model of normal intestinal epithelial cells (IPEC-J2), we researched the interaction between tight and adherens junctions and microfilaments of IPEC-J2 cells with these viruses. In our work, the results showed that IPEC-J2 cells were susceptible to TGEV and PEDV infection. And TGEV could impair the barrier integrity of IPEC-J2 cells at early stages of infection through down-regulating some proteins of tight and adherens junctions, while PEDV cloud cause a slight of damage in the integrity of epithelial barrier. In addition, they also could affect the microfilaments remodelling of IPEC-J2 cells, and the drug-interfered microfilaments could inhibit viral replication and release. Furthermore, PEDV+TGEV co-infection was more aggravating to damage of tight junctions and remodelling of microfilaments than their single infection. Finally, the PEDV and TGEV infection affected the MAPK pathway, and inhibition of MAPK pathway regulated the changes of tight junctions and microfilaments of cells. These studies provide a new insight from the perspective of the epithelial barrier and microfilaments into the pathogenesis of PEDV and TGEV.
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15
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Entry of a novel marine DNA virus, Singapore grouper iridovirus, into host cells occurs via clathrin-mediated endocytosis and macropinocytosis in a pH-dependent manner. J Virol 2014; 88:13047-63. [PMID: 25165116 DOI: 10.1128/jvi.01744-14] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Iridoviruses are nucleocytoplasmic DNA viruses which cause great economic losses in the aquaculture industry but also show significant threat to global biodiversity. However, a lack of host cells has resulted in poor progress in clarifying iridovirus behavior. We investigated the crucial events during virus entry using a combination of single-virus tracking and biochemical assays, based on the established virus-cell infection model for Singapore grouper iridovirus (SGIV). SGIV infection in host cells was strongly inhibited when cells were pretreated with drugs blocking clathrin-mediated endocytosis, including sucrose and chlorpromazine. Inhibition of key regulators of macropinocytosis, including Na(+)/H(+) exchanger, Rac1 GTPase, p21-activated kinase 1 (PAK1), protein kinase C (PKC), and myosin II, significantly reduced SGIV uptake. Cy5-labeled SGIV particles were observed to colocalize with clathrin and macropinosomes. In contrast, disruption of cellular cholesterol by methyl-β-cyclodextrin and nystatin had no effect on virus infection, suggesting that SGIV entered grouper cells via the clathrin-mediated endocytic pathway and macropinocytosis but not via caveola-dependent endocytosis. Furthermore, inhibitors of endosome acidification such as chloroquine and bafilomycin A1 blocked virus infection, indicating that SGIV entered cells in a pH-dependent manner. In addition, SGIV particles were observed to be transported along both microtubules and actin filaments, and intracellular SGIV motility was remarkably impaired by depolymerization of microtubules or actin filaments. The results of this study for the first time demonstrate that not only the clathrin-dependent pathway but also macropinocytosis are involved in fish DNA enveloped virus entry, thus providing a convenient tactic for exploring the life cycle of DNA viruses. IMPORTANCE Virus entry into host cells is critically important for initiating infections and is usually recognized as an ideal target for the design of antiviral strategies. Iridoviruses are large DNA viruses which cause serious threats to ecological diversity and the aquaculture industry worldwide. However, the current understanding of iridovirus entry is limited and controversial. Singapore grouper iridovirus (SGIV) is a novel marine fish DNA virus which belongs to genus Ranavirus, family Iridoviridae. Here, using single-virus tracking technology in combination with biochemical assays, we investigated the crucial events during SGIV entry and demonstrated that SGIV entered grouper cells via the clathrin-mediated endocytic pathway in a pH-dependent manner but not via caveola-dependent endocytosis. Furthermore, we propose for the first time that macropinocytosis is involved in iridovirus entry. Together, this work not only contributes greatly to understating iridovirus pathogenesis but also provides an ideal model for exploring the behavior of DNA viruses in living cells.
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Liang L, Li J, Li Q, Huang Q, Shi J, Yan H, Fan C. Single-Particle Tracking and Modulation of Cell Entry Pathways of a Tetrahedral DNA Nanostructure in Live Cells. Angew Chem Int Ed Engl 2014; 53:7745-50. [DOI: 10.1002/anie.201403236] [Citation(s) in RCA: 349] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Indexed: 12/11/2022]
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17
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Liang L, Li J, Li Q, Huang Q, Shi J, Yan H, Fan C. Single-Particle Tracking and Modulation of Cell Entry Pathways of a Tetrahedral DNA Nanostructure in Live Cells. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201403236] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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18
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Spear M, Guo J, Wu Y. Novel anti-HIV therapeutics targeting chemokine receptors and actin regulatory pathways. Immunol Rev 2014; 256:300-12. [PMID: 24117829 DOI: 10.1111/imr.12106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The human immunodeficiency virus-1 (HIV-1) infects helper CD4(+) T cells, and causes CD4(+) T-cell depletion and immunodeficiency. In the past 30 years, significant progress has been made in antiretroviral therapy, and the disease has become manageable. Nevertheless, an effective vaccine is still nowhere in sight, and a cure or a functional cure awaits discovery. Among possible curative therapies, traditional antiretroviral therapy, mostly targeting viral proteins, has been proven ineffective. It is possible that targeting HIV-dependent host cofactors may offer alternatives, both for preventing HIV transmission and for forestalling disease progression. Recently, the actin cytoskeleton and its regulators in blood CD4(+) T cells have emerged as major host cofactors that could be targeted. The novel concept that the cortical actin is a barrier to viral entry and early post-entry migration has led to the nascent model of virus-host interaction at the cortical actin layer. Deciphering the cellular regulatory pathways has manifested exciting prospects for future therapeutics. In this review, we describe the study of HIV interactions with actin cytoskeleton. We also examine potential pharmacological targets that emerge from this interaction. In addition, we briefly discuss several actin pathway-based anti-HIV drugs that are currently in development or testing.
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Affiliation(s)
- Mark Spear
- National Center for Biodefense and Infectious Diseases, Department of Molecular and Microbiology, George Mason University, Manassas, VA, USA
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19
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Liu SL, Zhang LJ, Wang ZG, Zhang ZL, Wu QM, Sun EZ, Shi YB, Pang DW. Globally visualizing the microtubule-dependent transport behaviors of influenza virus in live cells. Anal Chem 2014; 86:3902-8. [PMID: 24678700 PMCID: PMC4004192 DOI: 10.1021/ac500640u] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Accepted: 03/21/2014] [Indexed: 12/16/2022]
Abstract
Understanding the microtubule-dependent behaviors of viruses in live cells is very meaningful for revealing the mechanisms of virus infection and endocytosis. Herein, we used a quantum dots-based single-particle tracking technique to dynamically and globally visualize the microtubule-dependent transport behaviors of influenza virus in live cells. We found that the intersection configuration of microtubules can interfere with the transport behaviors of the virus in live cells, which lead to the changing and long-time pausing of the transport behavior of viruses. Our results revealed that most of the viruses moved along straight microtubules rapidly and unidirectionally from the cell periphery to the microtubule organizing center (MTOC) near the bottom of the cell, and the viruses were confined in the grid of microtubules near the top of the cell and at the MTOC near the bottom of the cell. These results provided deep insights into the influence of entire microtubule geometry on the virus infection.
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Affiliation(s)
- Shu-Lin Liu
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (Ministry
of Education), College of Chemistry and Molecular Sciences, State
Key Laboratory of Virology, and Wuhan Institute of Biotechnology, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Li-Juan Zhang
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (Ministry
of Education), College of Chemistry and Molecular Sciences, State
Key Laboratory of Virology, and Wuhan Institute of Biotechnology, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Zhi-Gang Wang
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (Ministry
of Education), College of Chemistry and Molecular Sciences, State
Key Laboratory of Virology, and Wuhan Institute of Biotechnology, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Zhi-Ling Zhang
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (Ministry
of Education), College of Chemistry and Molecular Sciences, State
Key Laboratory of Virology, and Wuhan Institute of Biotechnology, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Qiu-Mei Wu
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (Ministry
of Education), College of Chemistry and Molecular Sciences, State
Key Laboratory of Virology, and Wuhan Institute of Biotechnology, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - En-Ze Sun
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (Ministry
of Education), College of Chemistry and Molecular Sciences, State
Key Laboratory of Virology, and Wuhan Institute of Biotechnology, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Yun-Bo Shi
- Section
on Molecular Morphogenesis, PCRM, NICHD,
NIH, Bethesda, Maryland 20892-5431, United States
| | - Dai-Wen Pang
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (Ministry
of Education), College of Chemistry and Molecular Sciences, State
Key Laboratory of Virology, and Wuhan Institute of Biotechnology, Wuhan University, Wuhan, Hubei 430072, P.R. China
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20
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Alonas E, Lifland AW, Gudheti M, Vanover D, Jung J, Zurla C, Kirschman J, Fiore VF, Douglas A, Barker TH, Yi H, Wright ER, Crowe JE, Santangelo PJ. Combining single RNA sensitive probes with subdiffraction-limited and live-cell imaging enables the characterization of virus dynamics in cells. ACS NANO 2014; 8:302-15. [PMID: 24351207 PMCID: PMC3906890 DOI: 10.1021/nn405998v] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The creation of fluorescently labeled viruses is currently limited by the length of imaging observation time (e.g., labeling an envelope protein) and the rescue of viral infectivity (e.g., encoding a GFP protein). Using single molecule sensitive RNA hybridization probes delivered to the cytoplasm of infected cells, we were able to isolate individual, infectious, fluorescently labeled human respiratory syncytial virus virions. This was achieved without affecting viral mRNA expression, viral protein expression, or infectivity. Measurements included the characterization of viral proteins and genomic RNA in a single virion using dSTORM, the development of a GFP fusion assay, and the development of a pulse-chase assay for viral RNA production that allowed for the detection of both initial viral RNA and nascent RNA production at designated times postinfection. Live-cell measurements included imaging and characterization of filamentous virion fusion and the quantification of virus replication within the same cell over an eight-hour period. Using probe-labeled viruses, individual viral particles can be characterized at subdiffraction-limited resolution, and viral infections can be quantified in single cells over an entire cycle of replication. The implication of this development is that MTRIP labeling of viral RNA during virus assembly has the potential to become a general methodology for the labeling and study of many important RNA viruses.
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Affiliation(s)
- Eric Alonas
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Aaron W. Lifland
- Vutara, Inc., 615 Arapeen #304, Salt Lake City, Utah 84108, United States
| | - Manasa Gudheti
- Vutara, Inc., 615 Arapeen #304, Salt Lake City, Utah 84108, United States
| | - Daryll Vanover
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Jeenah Jung
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Chiara Zurla
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Jonathan Kirschman
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Vincent F. Fiore
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Alison Douglas
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Thomas H. Barker
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
| | - Hong Yi
- Robert P. Apkarian Integrated Electron Microscopy Core, College of Medicine, Emory University, Atlanta, Georgia 30322, United States
| | - Elizabeth R. Wright
- Robert P. Apkarian Integrated Electron Microscopy Core, College of Medicine, Emory University, Atlanta, Georgia 30322, United States
- Department of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, 2015 Uppergate Drive, NE, Suite 548, Atlanta, Georgia 30322, United States
| | - James E. Crowe
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Philip J. Santangelo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, Georgia 30332, United States
- Address correspondence to
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21
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Potokar M, Korva M, Jorgačevski J, Avšič-Županc T, Zorec R. Tick-borne encephalitis virus infects rat astrocytes but does not affect their viability. PLoS One 2014; 9:e86219. [PMID: 24465969 PMCID: PMC3896472 DOI: 10.1371/journal.pone.0086219] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 12/11/2013] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) causes one of the most dangerous human neuroinfections in Europe and Asia. To infect neurons it must cross the blood-brain-barrier (BBB), and presumably also cells adjacent to the BBB, such as astrocytes, the most abundant glial cell type. However, the knowledge about the viral infection of glial cells is fragmental. Here we studied whether TBEV infects rat astrocytes. Rats belong to an animal group serving as a TBEV amplifying host. We employed high resolution quantitative fluorescence microscopy to investigate cell entry and cytoplasmic mobility of TBEV particles along with the effect on the cell cytoskeleton and cell survival. We report that infection of astrocytes with TBEV increases with time of exposure to TBEV and that with post-infection time TBEV particles gained higher mobility. After several days of infection actin cytoskeleton was affected, but cell survival was unchanged, indicating that rat astrocytes resist TBEV-mediated cell death, as reported for other mammalian cells. Therefore, astrocytes may present an important pool of dormant TBEV infections and a new target for therapeutic intervention.
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Affiliation(s)
- Maja Potokar
- Celica Biomedical Center, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Miša Korva
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jernej Jorgačevski
- Celica Biomedical Center, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tatjana Avšič-Županc
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Robert Zorec
- Celica Biomedical Center, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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22
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Brandenburg B, Koudstaal W, Goudsmit J, Klaren V, Tang C, Bujny MV, Korse HJWM, Kwaks T, Otterstrom JJ, Juraszek J, van Oijen AM, Vogels R, Friesen RHE. Mechanisms of hemagglutinin targeted influenza virus neutralization. PLoS One 2013; 8:e80034. [PMID: 24348996 PMCID: PMC3862845 DOI: 10.1371/journal.pone.0080034] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/27/2013] [Indexed: 12/21/2022] Open
Abstract
Human monoclonal antibodies have been identified which neutralize broad spectra of influenza A or B viruses. Here, we dissect the mechanisms by which such antibodies interfere with infectivity. We distinguish four mechanisms that link the conserved hemagglutinin (HA) epitopes of broadly neutralizing antibodies to critical processes in the viral life cycle. HA-stem binding antibodies can act intracellularly by blocking fusion between the viral and endosomal membranes and extracellularly by preventing the proteolytic activation of HA. HA-head binding antibodies prevent viral attachment and release. These insights into newly identified ways by which the human immune system can interfere with influenza virus infection may aid the development of novel universal vaccines and antivirals.
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Affiliation(s)
- Boerries Brandenburg
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Wouter Koudstaal
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Jaap Goudsmit
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Vincent Klaren
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Chan Tang
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Miriam V. Bujny
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Hans J. W. M. Korse
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Ted Kwaks
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Jason J. Otterstrom
- Centre for Synthetic Biology, Zernike Institute for Advanced Materials, Groningen, The Netherlands
- Harvard Biophysics Program, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jarek Juraszek
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Antoine M. van Oijen
- Centre for Synthetic Biology, Zernike Institute for Advanced Materials, Groningen, The Netherlands
| | - Ronald Vogels
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
| | - Robert H. E. Friesen
- Crucell Vaccine Institute, Janssen Center of Excellence for Immunoprophylaxis, Leiden, The Netherlands
- * E-mail:
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23
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Vlecken DH, Pelgrim RP, Ruminski S, Bakker WA, van der Pol LA. Comparison of initial feasibility of host cell lines for viral vaccine production. J Virol Methods 2013; 193:28-41. [DOI: 10.1016/j.jviromet.2013.04.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 04/17/2013] [Accepted: 04/29/2013] [Indexed: 12/28/2022]
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24
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Barrow E, Nicola AV, Liu J. Multiscale perspectives of virus entry via endocytosis. Virol J 2013; 10:177. [PMID: 23734580 PMCID: PMC3679726 DOI: 10.1186/1743-422x-10-177] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 05/24/2013] [Indexed: 01/01/2023] Open
Abstract
Most viruses take advantage of endocytic pathways to gain entry into host cells and initiate infections. Understanding of virus entry via endocytosis is critically important for the design of antiviral strategies. Virus entry via endocytosis is a complex process involving hundreds of cellular proteins. The entire process is dictated by events occurring at multiple time and length scales. In this review, we discuss and evaluate the available means to investigate virus endocytic entry, from both experimental and theoretical/numerical modeling fronts, and highlight the importance of multiscale features. The complexity of the process requires investigations at a systems biology level, which involves the combination of different experimental approaches, the collaboration of experimentalists and theorists across different disciplines, and the development of novel multiscale models.
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Affiliation(s)
- Eric Barrow
- School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA
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25
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Sun E, He J, Zhuang X. Live cell imaging of viral entry. Curr Opin Virol 2013; 3:34-43. [PMID: 23395264 PMCID: PMC3587724 DOI: 10.1016/j.coviro.2013.01.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 12/14/2012] [Accepted: 01/21/2013] [Indexed: 12/17/2022]
Abstract
Viral entry encompasses the initial steps of infection starting from virion host cell attachment to viral genome release. Given the dynamic interactions between the virus and the host, many questions related to viral entry can be directly addressed by live cell imaging. Recent advances in fluorescent labeling of viral and cellular components, fluorescence microscopy with high sensitivity and spatiotemporal resolution, and image analysis enabled studies of a broad spectrum across many viral entry steps, including virus-receptor interactions, internalization, intracellular transport, genomic release, nuclear transport, and cell-to-cell transmission. Collectively, these live cell imaging studies have not only enriched our understandings of the viral entry mechanisms, but also provided novel insights into basic cellular biology processes.
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Affiliation(s)
- Eileen Sun
- Program in Virology, Harvard Medical School, Boston, MA 02115, United States
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26
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Abstract
As an obligate pathogen, influenza virus requires host cell factors and compartments to mediate productive infection and to produce infectious progeny virus. Recently, several small interfering RNA (siRNA) knockdown screens revealed influenza virus host dependency proteins, all of which identified at least two subunits of the coat protein I (COPI) complex. COPI proteins oligomerize to form coated vesicles that transport contents between the Golgi apparatus and the endoplasmic reticulum, and they have also been reported to mediate endosomal trafficking. However, it remains unclear which steps in the influenza virus infection cycle rely on the COPI complex. Upon systematic dissection of the influenza virus infection cycle, from entry to progeny virion production, we found that prolonged exposure to COPI complex disruption through siRNA depletion resulted in significant defects in virus internalization and trafficking to late endosomes. Acute inhibition of COPI complex recruitment to the Golgi apparatus with pharmacological compounds failed to recapitulate the same entry defects as observed with the COPI-depleted cells but did result in specific decreases in viral membrane protein expression and assembly, leading to defects in progeny virion production. Taken together, our findings suggest that COPI complexes likely function indirectly in influenza virus entry but play direct roles in viral membrane protein expression and assembly.
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27
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Hao J, Huang LL, Zhang R, Wang HZ, Xie HY. A mild and reliable method to label enveloped virus with quantum dots by copper-free click chemistry. Anal Chem 2012; 84:8364-70. [PMID: 22946933 DOI: 10.1021/ac301918t] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Real-time tracking of the dynamic process of virus invasion is crucial to understanding the infection mechanism. For successful tracking, efficient labeling methods are indispensable. In this paper, we report a mild and reliable method for labeling viruses, especially with regard to easily disabled enveloped viruses. The copper-free click chemistry has been used to label enveloped viruses with quantum dots (QDs) by linking virions modified with azide to the QDs derived with dibenzocyclooctynes (DBCO). Both vaccinia virus (VACV) and avian influenza A virus (H9N2) can be specifically and rapidly labeled under mild conditions, with a labeling efficiency of more than 80%. The labeled virions were of intact infectivity, and their fluorescence was strong enough to realize single-virion tracking. Compared to previously reported methods, our method is less destructive, reliable, and universal, without specific requirements for the type and structure of viruses to be labeled, which has laid the foundation for long-term dynamic visualization of virus infection process.
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Affiliation(s)
- Jian Hao
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
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28
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De Conto F, Di Lonardo E, Arcangeletti MC, Chezzi C, Medici MC, Calderaro A. Highly dynamic microtubules improve the effectiveness of early stages of human influenza A/NWS/33 virus infection in LLC-MK2 cells. PLoS One 2012; 7:e41207. [PMID: 22911759 PMCID: PMC3401105 DOI: 10.1371/journal.pone.0041207] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 06/18/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND This study aims to investigate the role of microtubule dynamics in the initiation of NWS/33 human influenza A (NWS) virus infection in MDCK and LLC-MK2 mammalian kidney cells. We previously demonstrated a host-dependent role of the actin cytoskeleton in inducing restriction during the early phases of NWS infection. Furthermore, we showed the differential infectious entry of NWS virus in the above mentioned cell models. METHODOLOGY/PRINCIPAL FINDINGS By first employing a panel of microtubule-modulators, we evidenced that microtubule-stabilization negatively interferes with NWS replication in LLC-MK2 but not in MDCK cells. Conversely, microtubule-depolymerization improves NWS growth in LLC-MK2 but not in the MDCK model. By using immunofluorescence labelling and Western blotting analyses upon NWS infection in mammalian kidney cells, it was observed that the occurrence of alpha-tubulin hyperacetylation--a post-translational modified form suggestive of stable microtubules--was significantly delayed in LLC-MK2 when compared to MDCK cells. Furthermore, mock-infected LLC-MK2 cells were shown to have higher levels of both acetylated alpha-tubulin and microtubule-associated protein 4 (MAP4), the latter being essential for the maintenance of normal microtubule polymer levels in interphase epithelial cells. Finally, to obtain highly dynamic microtubules in LLC-MK2 cells, we knocked down the expression of MAP4 by using a RNA-mediated RNA interference approach. The results evidenced that MAP4 silencing improves NWS growth in LLC-MK2 cells. CONCLUSION By evidencing the cell type-dependent regulatory role of microtubule dynamics on NWS replication in mammalian kidney cells, we demonstrated that microtubule-stabilization represents a restriction factor for the initiation of NWS infection in LLC-MK2 but not in MDCK cells.
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Affiliation(s)
- Flora De Conto
- Section of Microbiology, Department of Pathology and Laboratory Medicine, University of Parma, Parma, Italy.
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29
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Jayappa KD, Ao Z, Yao X. The HIV-1 passage from cytoplasm to nucleus: the process involving a complex exchange between the components of HIV-1 and cellular machinery to access nucleus and successful integration. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 3:70-85. [PMID: 22509482 PMCID: PMC3325773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/22/2012] [Indexed: 05/31/2023]
Abstract
The human immunodeficiency virus 1 (HIV-1) synthesizes its genomic DNA in cytoplasm as soon as it enters the cell. The newly synthesized DNA remains associated with viral/cellular proteins as a high molecular weight pre-integration complex (PIC), which precludes passive diffusion across intact nuclear membrane. However, HIV-1 successfully overcomes nuclear membrane barrier by actively delivering its DNA into nucleus with the help of host nuclear import machinery. Such ability allows HIV-1 to productively infect non-dividing cells as well as dividing cells at interphase. Further, HIV-1 nuclear import is also found important for the proper integration of viral DNA. Thus, nuclear import plays a crucial role in establishment of infection and disease progression. While several viral components, including matrix, viral protein R, integrase, capsid, and central DNA flap are implicated in HIV-1 nuclear import, their molecular mechanism remains poorly understood. In this review, we will elaborate the role of individual viral factors and some of current insights on their molecular mechanism(s) associated with HIV-1 nuclear import. In addition, we will discuss the importance of nuclear import for subsequent step of viral DNA integration. Hereby we aim to further our understanding on molecular mechanism of HIV-1 nuclear import and its potential usefulness for anti-HIV-1 strategies.
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Affiliation(s)
- Kallesh Danappa Jayappa
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba Winnipeg, MB, Canada
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30
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Liu SL, Zhang ZL, Tian ZQ, Zhao HS, Liu H, Sun EZ, Xiao GF, Zhang W, Wang HZ, Pang DW. Effectively and efficiently dissecting the infection of influenza virus by quantum-dot-based single-particle tracking. ACS NANO 2012; 6:141-150. [PMID: 22117089 DOI: 10.1021/nn2031353] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Exploring the virus infection mechanisms is significant for defending against virus infection and providing a basis for studying endocytosis mechanisms. Single-particle tracking technique is a powerful tool to monitor virus infection in real time for obtaining dynamic information. In this study, we reported a quantum-dot-based single-particle tracking technique to efficiently and globally research the virus infection behaviors in individual cells. It was observed that many influenza viruses were moving rapidly, converging to the microtubule organizing center (MTOC), interacting with acidic endosomes, and finally entering the target endosomes for genome release, which provides a vivid portrayal of the five-stage virus infection process. This report settles a long-pending question of how viruses move and interact with acidic endosomes before genome release in the perinuclear region and also finds that influenza virus infection is likely to be a "MTOC rescue" model for genome release. The systemic technique developed in this report is expected to be widely used for studying the mechanisms of virus infection and uncovering the secrets of endocytosis.
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Affiliation(s)
- Shu-Lin Liu
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Research Center for Nanobiology and Nanomedicine (MOE 985 Innovative Platform), Wuhan University, Wuhan 430072, People's Republic of China
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31
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Brandenburg B, Bujny MV, Gelderblom HR. Optische und Elektronenmikroskopische Detektion – Erregerschnelldiagnostik, hochauflösende Lichtmikroskopie und Live-Cell-Imaging. LEXIKON DER INFEKTIONSKRANKHEITEN DES MENSCHEN 2012. [PMCID: PMC7122969 DOI: 10.1007/978-3-642-17158-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Die Kombination aus Zellbiologie und Mikrobiologie hat mit der Zellulären Mikrobiologie eine neue Disziplin geschaffen, deren primäres Ziel die Erforschung des Zusammenspiels von Wirt und Erregern auf der Ebene des Gewebes, der Zelle und letztlich von einzelnen Molekülen ist. Die Entschlüsselung dieser dynamischen Interaktionen erlaubt ein tiefgreifendes Verständnis von Infektionsmechanismen sowie zellulärer Logistik und bereitet damit den Weg für die Entwicklung wirkungsvoller Therapeutika.
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32
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Visualizing the endocytic and exocytic processes of wheat germ agglutinin by quantum dot-based single-particle tracking. Biomaterials 2011; 32:7616-24. [DOI: 10.1016/j.biomaterials.2011.06.046] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 06/20/2011] [Indexed: 11/18/2022]
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33
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Macrophage-mediated optic neuritis induced by retrograde axonal transport of spike gene recombinant mouse hepatitis virus. J Neuropathol Exp Neurol 2011; 70:470-80. [PMID: 21572336 PMCID: PMC3110774 DOI: 10.1097/nen.0b013e31821da499] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
After intracranial inoculation, neurovirulent mouse hepatitis virus (MHV) strains induce acute inflammation, demyelination, and axonal loss in the central nervous system. Prior studies using recombinant MHV strains that differ only in the spike gene, which encodes a glycoprotein involved in virus-host cell attachment, demonstrated that spike mediates anterograde axonal transport of virus to the spinal cord. A demyelinating MHV strain induces optic neuritis, but whether this is due to the retrograde axonal transport of viral particles to the retina or due to traumatic disruption of retinal ganglion cell axons during intracranial inoculation is not known. Using recombinant isogenic MHV strains, we examined the ability of recombinant MHV to induce optic neuritis by retrograde spread from the brain through the optic nerve into the eye after intracranial inoculation. Recombinant demyelinating MHV induced macrophage infiltration of optic nerves, demyelination, and axonal loss, whereas optic neuritis and axonal injury were minimal in mice infected with the nondemyelinating MHV strain that differs in the spike gene. Thus, optic neuritis was dependent on a spike glycoprotein-mediated mechanism of viral antigen transport along retinal ganglion cell axons. These data indicate that MHV spreads by retrograde axonal transport to the eye and that targeting spike protein interactions with axonal transport machinery is a potential therapeutic strategy for central nervous system viral infections and associated diseases.
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Hao X, Shang X, Wu J, Shan Y, Cai M, Jiang J, Huang Z, Tang Z, Wang H. Single-particle tracking of hepatitis B virus-like vesicle entry into cells. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:1212-1218. [PMID: 21456082 DOI: 10.1002/smll.201002020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/03/2011] [Indexed: 05/30/2023]
Abstract
HBsAg, the surface antigen of the hepatitis B virus (HBV), is used as a model to study the mechanisms and dynamics of a single-enveloped virus infecting living cells by imaging and tracking at the single-particle level. By monitoring the fluorescent indicator of HBsAg particles, it is found that HBsAg enters cells via a caveolin-mediated endocytic pathway. Tracking of individual HBsAg particles in living cells reveals the anomalously actin-dependent but not microtubule-dependent motility of the internalized HBsAg particle. The motility of HBsAg particles in living cells is also analyzed quantitatively. These results may settle the long-lasting debate of whether HBV directly breaks the plasma membrane barrier or relies on endocytosis to deliver its genome into the cell, and how the virus moves in the cell.
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Affiliation(s)
- Xian Hao
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
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Abstract
Viral infection converts the normal functions of a cell to optimize viral replication and virion production. One striking observation of this conversion is the reconfiguration and reorganization of cellular actin, affecting every stage of the viral life cycle, from entry through assembly to egress. The extent and degree of cytoskeletal reorganization varies among different viral infections, suggesting the evolution of myriad viral strategies. In this Review, we describe how the interaction of viral proteins with the cell modulates the structure and function of the actin cytoskeleton to initiate, sustain and spread infections. The molecular biology of such interactions continues to engage virologists in their quest to understand viral replication and informs cell biologists about the role of the cytoskeleton in the uninfected cell.
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36
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100 years poliovirus: from discovery to eradication. A meeting report. Arch Virol 2010; 155:1371-81. [DOI: 10.1007/s00705-010-0778-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 07/26/2010] [Indexed: 10/19/2022]
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37
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Abstract
The picornavirus family consists of a large number of small RNA viruses, many of which are significant pathogens of humans and livestock. They are amongst the simplest of vertebrate viruses comprising a single stranded positive sense RNA genome within a T = 1 (quasi T = 3) icosahedral protein capsid of approximately 30 nm diameter. The structures of a number of picornaviruses have been determined at close to atomic resolution by X-ray crystallography. The structures of cell entry intermediate particles and complexes of virus particles with receptor molecules or antibodies have also been obtained by X-ray crystallography or at a lower resolution by cryo-electron microscopy. Many of the receptors used by different picornaviruses have been identified, and it is becoming increasingly apparent that many use co-receptors and alternative receptors to bind to and infect cells. However, the mechanisms by which these viruses release their genomes and transport them across a cellular membrane to gain access to the cytoplasm are still poorly understood. Indeed, detailed studies of cell entry mechanisms have been made only on a few members of the family, and it is yet to be established how broadly the results of these are applicable across the full spectrum of picornaviruses. Working models of the cell entry process are being developed for the best studied picornaviruses, the enteroviruses. These viruses maintain particle integrity throughout the infection process and function as genome delivery modules. However, there is currently no model to explain how viruses such as cardio- and aphthoviruses that appear to simply dissociate into subunits during uncoating deliver their genomes into the cytoplasm.
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Affiliation(s)
- Tobias J. Tuthill
- Faculty of Biological Sciences, Institute for Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, West Yorkshire LS2 9JT, UK, Institute for Animal Health, Pirbright, Surrey GU24 ONF, UK,
| | - Elisabetta Groppelli
- Faculty of Biological Sciences Institute for Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, West Yorkshire LS2 9JT UK
| | - James M. Hogle
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA,
| | - David J. Rowlands
- Faculty of Biological Sciences Institute for Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, West Yorkshire LS2 9JT UK
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