1
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Kapoor KS, Kong S, Sugimoto H, Guo W, Boominathan V, Chen YL, Biswal SL, Terlier T, McAndrews KM, Kalluri R. Single Extracellular Vesicle Imaging and Computational Analysis Identifies Inherent Architectural Heterogeneity. ACS NANO 2024; 18:11717-11731. [PMID: 38651873 DOI: 10.1021/acsnano.3c12556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Evaluating the heterogeneity of extracellular vesicles (EVs) is crucial for unraveling their complex actions and biodistribution. Here, we identify consistent architectural heterogeneity of EVs using cryogenic transmission electron microscopy (cryo-TEM), which has an inherent ability to image biological samples without harsh labeling methods while preserving their native conformation. Imaging EVs isolated using different methodologies from distinct sources, such as cancer cells, normal cells, immortalized cells, and body fluids, we identify a structural atlas of their dominantly consistent shapes. We identify EV architectural attributes by utilizing a segmentation neural network model. In total, 7,576 individual EVs were imaged and quantified by our computational pipeline. Across all 7,576 independent EVs, the average eccentricity was 0.5366 ± 0.2, and the average equivalent diameter was 132.43 ± 67 nm. The architectural heterogeneity was consistent across all sources of EVs, independent of purification techniques, and compromised of single spherical, rod-like or tubular, and double shapes. This study will serve as a reference foundation for high-resolution images of EVs and offer insights into their potential biological impact.
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Affiliation(s)
- Kshipra S Kapoor
- Department of Cancer Biology and Metastasis Research Center, The University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
| | - Seoyun Kong
- Department of Cancer Biology and Metastasis Research Center, The University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Hikaru Sugimoto
- Department of Cancer Biology and Metastasis Research Center, The University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Wenhua Guo
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Vivek Boominathan
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
| | - Yi-Lin Chen
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Sibani Lisa Biswal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Tanguy Terlier
- SIMS Laboratory, Shared Equipment Authority, Rice University, Houston, Texas 77005, United States
| | - Kathleen M McAndrews
- Department of Cancer Biology and Metastasis Research Center, The University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Raghu Kalluri
- Department of Cancer Biology and Metastasis Research Center, The University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
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2
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Pan X, Wang J, Zhang K, Sun P, Shi J, Zhi J, Cai Z, Li Z, Wang D, Tong B, Dong Y. Differential detection of H1N1 virus spiker proteins by two hexaphenylbutadiene isomers based on size-matching principle. Anal Chim Acta 2024; 1299:342452. [PMID: 38499411 DOI: 10.1016/j.aca.2024.342452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 02/05/2024] [Accepted: 03/05/2024] [Indexed: 03/20/2024]
Abstract
As one of the high pathogenic influenza viruses, H1N1 virus easily induces to serious diseases, even leading to death. To date, all detection methods for H1N1 virus had shortcomings, including high equipment cost, time consumption, and etc. Therefore, a novel detection method should be established to achieve more convenient, rapid, and low-cost detection. In this work, an isomer of HPBmN-I with aggregation-induced emission characteristic was firstly synthesized on the basis of our previous reported HPBpN-I. The results showed that HPBmN-I only selectively binds to N1 in the presence of H1, while HPBpN-I can exhibit total fluorescence response to H1 and N1 in H1/N1 mixture. The limited of detection (LOD) of HPBmN-I to N1 was estimated to be 20.82 ng/mL in normal saline (NS) according to the IUPAC-based approach. The simulation calculations based on molecular docking revealed that four HPBmN-I molecules combine well with the hydrophobic cavity of N1 and achieve the fluorescence enhancement due to size matching with each other. The combination of HPBpN-I and HPBmN-I as probes was successfully used to quantitatively detect H1 and N1 in real H1N1 virus. Compared to enzyme-linked immunosorbent assay (ELISA) method, the established method not only showed the same detection accuracy but also had the advantages of real-time, ease of preparation, and low-cost, demonstrating potential market prospects.
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Affiliation(s)
- Xiaoling Pan
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Material Science & Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China; Department of Nanomedicine & Shanghai Key Lab of Cell Engineering, Naval Medical University, Shanghai, 200433, China
| | - Jian Wang
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Material Science & Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Kai Zhang
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Material Science & Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Peng Sun
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Jianbing Shi
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Material Science & Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Junge Zhi
- School of Chemistry, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Zhengxu Cai
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Material Science & Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Zi Li
- National Institute for Viral Disease Control and Prevention, Collaboration Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health and Family Planning Commission, Beijing, 102206, China
| | - Dayan Wang
- National Institute for Viral Disease Control and Prevention, Collaboration Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health and Family Planning Commission, Beijing, 102206, China
| | - Bin Tong
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Material Science & Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China.
| | - Yuping Dong
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Material Science & Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China.
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3
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Pereira TA, Espósito BP. Can iron chelators ameliorate viral infections? Biometals 2024; 37:289-304. [PMID: 38019378 DOI: 10.1007/s10534-023-00558-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 10/25/2023] [Indexed: 11/30/2023]
Abstract
The redox reactivity of iron is a double-edged sword for cell functions, being either essential or harmful depending on metal concentration and location. Deregulation of iron homeostasis is associated with several clinical conditions, including viral infections. Clinical studies as well as in silico, in vitro and in vivo models show direct effects of several viruses on iron levels. There is support for the strategy of iron chelation as an alternative therapy to inhibit infection and/or viral replication, on the rationale that iron is required for the synthesis of some viral proteins and genes. In addition, abnormal iron levels can affect signaling immune response. However, other studies report different effects of viral infections on iron homeostasis, depending on the class and genotype of the virus, therefore making it difficult to predict whether iron chelation would have any benefit. This review brings general aspects of the relationship between iron homeostasis and the nonspecific immune response to viral infections, along with its relevance to the progress or inhibition of the inflammatory process, in order to elucidate situations in which the use of iron chelators could be efficient as antivirals.
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4
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Hook JL, Bhattacharya J. The pathogenesis of influenza in intact alveoli: virion endocytosis and its effects on the lung's air-blood barrier. Front Immunol 2024; 15:1328453. [PMID: 38343548 PMCID: PMC10853445 DOI: 10.3389/fimmu.2024.1328453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 01/03/2024] [Indexed: 02/15/2024] Open
Abstract
Lung infection by influenza A virus (IAV) is a major cause of global mortality from lung injury, a disease defined by widespread dysfunction of the lung's air-blood barrier. Endocytosis of IAV virions by the alveolar epithelium - the cells that determine barrier function - is central to barrier loss mechanisms. Here, we address the current understanding of the mechanistic steps that lead to endocytosis in the alveolar epithelium, with an eye to how the unique structure of lung alveoli shapes endocytic mechanisms. We highlight where future studies of alveolar interactions with IAV virions may lead to new therapeutic approaches for IAV-induced lung injury.
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Affiliation(s)
- Jaime L. Hook
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Global Health and Emerging Pathogens Institute, Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Jahar Bhattacharya
- Department of Medicine, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY, United States
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY, United States
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5
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Kapoor KS, Kong S, Sugimoto H, Guo W, Boominathan V, Chen YL, Biswal SL, Terlier T, McAndrews KM, Kalluri R. Single extracellular vesicle imaging and computational analysis identifies inherent architectural heterogeneity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.11.571132. [PMID: 38168235 PMCID: PMC10760062 DOI: 10.1101/2023.12.11.571132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Evaluating the heterogeneity of extracellular vesicles (EVs) is crucial for unraveling their complex actions and biodistribution. Here, we identify consistent architectural heterogeneity of EVs using cryogenic transmission electron microscopy (cryo-TEM) which has an inherent ability to image biological samples without harsh labeling methods and while preserving their native conformation. Imaging EVs isolated using different methodologies from distinct sources such as cancer cells, normal cells, and body fluids, we identify a structural atlas of their dominantly consistent shapes. We identify EV architectural attributes by utilizing a segmentation neural network model. In total, 7,576 individual EVs were imaged and quantified by our computational pipeline. Across all 7,576 independent EVs, the average eccentricity was 0.5366, and the average equivalent diameter was 132.43 nm. The architectural heterogeneity was consistent across all sources of EVs, independent of purification techniques, and compromised of single spherical (S. Spherical), rod-like or tubular, and double shapes. This study will serve as a reference foundation for high-resolution EV images and offer insights into their potential biological impact.
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6
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Petkidis A, Andriasyan V, Greber UF. Machine learning for cross-scale microscopy of viruses. CELL REPORTS METHODS 2023; 3:100557. [PMID: 37751685 PMCID: PMC10545915 DOI: 10.1016/j.crmeth.2023.100557] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/05/2023] [Accepted: 07/20/2023] [Indexed: 09/28/2023]
Abstract
Despite advances in virological sciences and antiviral research, viruses continue to emerge, circulate, and threaten public health. We still lack a comprehensive understanding of how cells and individuals remain susceptible to infectious agents. This deficiency is in part due to the complexity of viruses, including the cell states controlling virus-host interactions. Microscopy samples distinct cellular infection stages in a multi-parametric, time-resolved manner at molecular resolution and is increasingly enhanced by machine learning and deep learning. Here we discuss how state-of-the-art artificial intelligence (AI) augments light and electron microscopy and advances virological research of cells. We describe current procedures for image denoising, object segmentation, tracking, classification, and super-resolution and showcase examples of how AI has improved the acquisition and analyses of microscopy data. The power of AI-enhanced microscopy will continue to help unravel virus infection mechanisms, develop antiviral agents, and improve viral vectors.
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Affiliation(s)
- Anthony Petkidis
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| | - Vardan Andriasyan
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Urs F Greber
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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7
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Yuanyuan H, Zijian G, Subiaur S, Benegal A, Vahey MD. Antibody Inhibition of Influenza A Virus Assembly and Release. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552198. [PMID: 37609131 PMCID: PMC10441363 DOI: 10.1101/2023.08.08.552198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Antibodies are frontline defenders against influenza virus infection, providing protection through multiple complementary mechanisms. Although a subset of monoclonal antibodies (mAbs) have been shown to restrict replication at the level of virus assembly and release, it remains unclear how potent and pervasive this mechanism of protection is, due in part to the challenge of separating this effect from other aspects of antibody function. To address this question, we developed imaging-based assays to determine how effectively a broad range of mAbs against the IAV surface proteins can specifically restrict viral egress. We find that classically neutralizing antibodies against hemagglutinin are broadly multifunctional, inhibiting virus assembly and release at concentrations one- to twenty-fold higher than the concentrations at which they inhibit viral entry. These antibodies are also capable of altering the morphological features of shed virions, reducing the proportion of filamentous particles. We find that antibodies against neuraminidase and M2 also restrict viral egress, and that inhibition by anti-neuraminidase mAbs is only partly attributable to a loss in enzymatic activity. In all cases, antigen crosslinking - either on the surface of the infected cell, between the viral and cell membrane, or both - plays a critical role in inhibition, and we are able to distinguish between these modes experimentally and through a structure-based computational model. Together, these results provide a framework for dissecting antibody multifunctionality that could help guide the development of improved therapeutic antibodies or vaccines, and that can be extended to other viral families and antibody isotypes.
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Affiliation(s)
- He Yuanyuan
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Guo Zijian
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Sofie Subiaur
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Ananya Benegal
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Michael D. Vahey
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, Missouri, USA
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8
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McMahon A, Andrews R, Groves D, Ghani SV, Cordes T, Kapanidis AN, Robb NC. High-throughput super-resolution analysis of influenza virus pleomorphism reveals insights into viral spatial organization. PLoS Pathog 2023; 19:e1011484. [PMID: 37390113 DOI: 10.1371/journal.ppat.1011484] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 06/14/2023] [Indexed: 07/02/2023] Open
Abstract
Many viruses form highly pleomorphic particles. In influenza, virion structure is of interest not only in the context of virus assembly, but also because pleomorphic variations may correlate with infectivity and pathogenicity. We have used fluorescence super-resolution microscopy combined with a rapid automated analysis pipeline, a method well-suited to the study of large numbers of pleomorphic structures, to image many thousands of individual influenza virions; gaining information on their size, morphology and the distribution of membrane-embedded and internal proteins. We observed broad phenotypic variability in filament size, and Fourier transform analysis of super resolution images demonstrated no generalized common spatial frequency patterning of HA or NA on the virion surface, suggesting a model of virus particle assembly where the release of progeny filaments from cells occurs in a stochastic way. We also showed that viral RNP complexes are located preferentially within Archetti bodies when these were observed at filament ends, suggesting that these structures may play a role in virus transmission. Our approach therefore offers exciting new insights into influenza virus morphology and represents a powerful technique that is easily extendable to the study of pleomorphism in other pathogenic viruses.
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Affiliation(s)
- Andrew McMahon
- Biological Physics, Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, United Kingdom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Rebecca Andrews
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Danielle Groves
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Sohail V Ghani
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr, Planegg-Martinsried, Germany
| | - Achillefs N Kapanidis
- Biological Physics, Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, United Kingdom
| | - Nicole C Robb
- Biological Physics, Department of Physics, University of Oxford, Oxford, United Kingdom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
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9
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Parshad B, Schlecht MN, Baumgardt M, Ludwig K, Nie C, Rimondi A, Hönzke K, Angioletti-Uberti S, Khatri V, Schneider P, Herrmann A, Haag R, Hocke AC, Wolff T, Bhatia S. Dual-Action Heteromultivalent Glycopolymers Stringently Block and Arrest Influenza A Virus Infection In Vitro and Ex Vivo. NANO LETTERS 2023; 23:4844-4853. [PMID: 37220024 DOI: 10.1021/acs.nanolett.3c00408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Here, we demonstrate the concerted inhibition of different influenza A virus (IAV) strains using a low-molecular-weight dual-action linear polymer. The 6'-sialyllactose and zanamivir conjugates of linear polyglycerol are optimized for simultaneous targeting of hemagglutinin and neuraminidase on the IAV surface. Independent of IAV subtypes, hemagglutination inhibition data suggest better adsorption of the heteromultivalent polymer than homomultivalent analogs onto the virus surface. Cryo-TEM images imply heteromultivalent compound-mediated virus aggregation. The optimized polymeric nanomaterial inhibits >99.9% propagation of various IAV strains 24 h postinfection in vitro at low nM concentrations and is up to 10000× more effective than the commercial zanamivir drug. In a human lung ex vivo multicyclic infection setup, the heteromultivalent polymer outperforms the commercial drug zanamivir and homomultivalent analogs or their physical mixtures. This study authenticates the translational potential of the dual-action targeting approach using small polymers for broad and high antiviral efficacy.
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Affiliation(s)
- Badri Parshad
- Institut für Chemie und Biochemie Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, United States
| | - Marlena N Schlecht
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353 Berlin, Germany
- Medical Clinic III, Division of Nephrology, Medizinische Fakultät Carl Gustav Carus an der TU Dresden, Fiedlerstr. 40, 01307 Dresden, Germany
| | - Morris Baumgardt
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Kai Ludwig
- Forschungszentrum für Elektronenmikroskopie and Core Facility BioSupraMol, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstr. 36a, 14195 Berlin, Germany
| | - Chuanxiong Nie
- Institut für Chemie und Biochemie Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Agustina Rimondi
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353 Berlin, Germany
| | - Katja Hönzke
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | | | - Vinod Khatri
- Institut für Chemie und Biochemie Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Paul Schneider
- Department for Thoracic Surgery, DRK Clinics, 13359 Berlin, Germany
| | - Andreas Herrmann
- Institut für Chemie und Biochemie Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Rainer Haag
- Institut für Chemie und Biochemie Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Andreas C Hocke
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Thorsten Wolff
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353 Berlin, Germany
| | - Sumati Bhatia
- Institut für Chemie und Biochemie Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
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10
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Hamming PHE, Overeem NJ, Diestelhorst K, Fiers T, Tieke M, Vos GM, Boons GJPH, van der Vries E, Block S, Huskens J. Receptor Density-Dependent Motility of Influenza Virus Particles on Surface Gradients. ACS APPLIED MATERIALS & INTERFACES 2023; 15:25066-25076. [PMID: 37167605 DOI: 10.1021/acsami.3c05299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Influenza viruses can move across the surface of host cells while interacting with their glycocalyx. This motility may assist in finding or forming locations for cell entry and thereby promote cellular uptake. Because the binding to and cleavage of cell surface receptors forms the driving force for the process, the surface-bound motility of influenza is expected to be dependent on the receptor density. Surface gradients with gradually varying receptor densities are thus a valuable tool to study binding and motility processes of influenza and can function as a mimic for local receptor density variations at the glycocalyx that may steer the directionality of a virus particle in finding the proper site of uptake. We have tracked individual influenza virus particles moving over surfaces with receptor density gradients. We analyzed the extracted virus tracks first at a general level to verify neuraminidase activity and subsequently with increasing detail to quantify the receptor density-dependent behavior on the level of individual virus particles. While a directional bias was not observed, most likely due to limitations of the steepness of the surface gradient, the surface mobility and the probability of sticking were found to be significantly dependent on receptor density. A combination of high surface mobility and high dissociation probability of influenza was observed at low receptor densities, while the opposite occurred at higher receptor densities. These properties result in an effective mechanism for finding high-receptor density patches, which are believed to be a key feature of potential locations for cell entry.
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Affiliation(s)
- P H Erik Hamming
- Molecular Nanofabrication Group, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Nico J Overeem
- Molecular Nanofabrication Group, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Kevin Diestelhorst
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Tren Fiers
- Molecular Nanofabrication Group, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Malte Tieke
- Division of Virology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
| | - Gaël M Vos
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Geert-Jan P H Boons
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Erhard van der Vries
- Division of Virology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
- Royal GD, Arnsbergstraat 7, 7418 EZ Deventer, The Netherlands
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Stephan Block
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Jurriaan Huskens
- Molecular Nanofabrication Group, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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11
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Madsen JJ, Rossman JS. Cholesterol and M2 Rendezvous in Budding and Scission of Influenza A Virus. Subcell Biochem 2023; 106:441-459. [PMID: 38159237 DOI: 10.1007/978-3-031-40086-5_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The cholesterol of the host cell plasma membrane and viral M2 protein plays a crucial role in multiple stages of infection and replication of the influenza A virus. Cholesterol is required for the formation of heterogeneous membrane microdomains (or rafts) in the budozone of the host cell that serves as assembly sites for the viral components. The raft microstructures act as scaffolds for several proteins. Cholesterol may further contribute to the mechanical forces necessary for membrane scission in the last stage of budding and help to maintain the stability of the virus envelope. The M2 protein has been shown to cause membrane scission in model systems by promoting the formation of curved lipid bilayer structures that, in turn, can lead to membrane vesicles budding off or scission intermediates. Membrane remodeling by M2 is intimately linked with cholesterol as it affects local lipid composition, fluidity, and stability of the membrane. Thus, both cholesterol and M2 protein contribute to the efficient and proper release of newly formed influenza viruses from the virus-infected cells.
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Affiliation(s)
- Jesper J Madsen
- Global and Planetary Health, Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, FL, USA.
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
| | - Jeremy S Rossman
- School of Biosciences, University of Kent, Canterbury, Kent, UK
- Research-Aid Networks, Chicago, IL, USA
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12
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Liu T, Wang Y, Tan TJC, Wu NC, Brooke CB. The evolutionary potential of influenza A virus hemagglutinin is highly constrained by epistatic interactions with neuraminidase. Cell Host Microbe 2022; 30:1363-1369.e4. [PMID: 36150395 PMCID: PMC9588755 DOI: 10.1016/j.chom.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/27/2022] [Accepted: 09/02/2022] [Indexed: 11/03/2022]
Abstract
Antigenic evolution of the influenza A virus (IAV) hemagglutinin (HA) gene limits efforts to effectively control the spread of the virus in the population. Efforts to understand the mechanisms governing HA antigenic evolution typically examine the HA gene in isolation. This can ignore the importance of balancing HA receptor binding activities with the receptor-destroying activities of the viral neuraminidase (NA) to maintain viral fitness. We hypothesize that the need to maintain functional balance with NA significantly constrains the evolutionary potential of the HA. We use deep mutational scanning and show that variation in NA activity significantly reshapes the HA fitness landscape by modulating the overall mutational robustness of HA. Consistent with this, we observe that different NA backgrounds support the emergence of distinct repertoires of HA escape variants under neutralizing antibody pressure. Our results reveal a critical role for intersegment epistasis in influencing the evolutionary potential of the HA gene.
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Affiliation(s)
- Tongyu Liu
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yiquan Wang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Timothy J C Tan
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Nicholas C Wu
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Christopher B Brooke
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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13
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Li Z, Li T, Liu M, Ivanovic T. Hemagglutinin Stability Determines Influenza A Virus Susceptibility to a Broad-Spectrum Fusion Inhibitor Arbidol. ACS Infect Dis 2022; 8:1543-1552. [PMID: 35819162 PMCID: PMC9810120 DOI: 10.1021/acsinfecdis.2c00178] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Understanding mechanisms of resistance to antiviral inhibitors can reveal nuanced features of targeted viral mechanisms and, in turn, lead to improved strategies for inhibitor design. Arbidol is a broad-spectrum antiviral that binds to and prevents the fusion-associated conformational changes in the trimeric influenza A virus (IAV) hemagglutinin (HA). The rate-limiting step during the HA-mediated membrane fusion is the release of the hydrophobic fusion peptides from a conserved pocket on HA. Here, we investigated how destabilizing or stabilizing mutations in or near the fusion peptide affect viral sensitivity to Arbidol. The degree of sensitivity was proportional to the extent of fusion-peptide stability on the prefusion HA: stabilized mutants were more sensitive, and destabilized ones were resistant to Arbidol. Single-virion membrane fusion experiments for representative wild-type (WT) and mutant viruses demonstrated that resistance is a direct consequence of fusion-peptide destabilization not requiring reduced Arbidol binding to HA. Our results support the model whereby the probability of individual HAs extending to engage the target membrane is determined by the composite of two critical forces: a "tug" on the fusion peptide by HA rearrangements near the Arbidol binding site and the key interactions stabilizing the fusion peptide in the prefusion pocket. Arbidol increases and destabilizing mutations decrease the free-energy cost for fusion-peptide release, accounting for the observed resistance. Our findings have broad implications for fusion inhibitor design, viral mechanisms of resistance, and our basic understanding of HA-mediated membrane fusion.
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14
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Abstract
We discuss the genetic, demographic, and selective forces that are likely to be at play in restricting observed levels of DNA sequence variation in natural populations to a much smaller range of values than would be expected from the distribution of census population sizes alone-Lewontin's Paradox. While several processes that have previously been strongly emphasized must be involved, including the effects of direct selection and genetic hitchhiking, it seems unlikely that they are sufficient to explain this observation without contributions from other factors. We highlight a potentially important role for the less-appreciated contribution of population size change; specifically, the likelihood that many species and populations may be quite far from reaching the relatively high equilibrium diversity values that would be expected given their current census sizes.
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Affiliation(s)
- Brian Charlesworth
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Jeffrey D Jensen
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
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15
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Wu X, Zheng Z, Chen H, Lin H, Yang Y, Bai Y, Xia Q. Sterilization of Drug‐Resistant Influenza Virus Through Genetic Interference Inspired by Unnatural Amino Acid‐Engineered Particles. ADVANCED THERAPEUTICS 2022. [DOI: 10.1002/adtp.202200069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Xuesheng Wu
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences Peking University Beijing 100191 China
| | - Zhetao Zheng
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences Peking University Beijing 100191 China
| | - Hongmin Chen
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences Peking University Beijing 100191 China
| | - Haishuang Lin
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences Peking University Beijing 100191 China
| | - Yuelin Yang
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences Peking University Beijing 100191 China
| | - Yachao Bai
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences Peking University Beijing 100191 China
| | - Qing Xia
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences Peking University Beijing 100191 China
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16
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A Virus Is a Community: Diversity within Negative-Sense RNA Virus Populations. Microbiol Mol Biol Rev 2022; 86:e0008621. [PMID: 35658541 DOI: 10.1128/mmbr.00086-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Negative-sense RNA virus populations are composed of diverse viral components that interact to form a community and shape the outcome of virus infections. At the genomic level, RNA virus populations consist not only of a homogeneous population of standard viral genomes but also of an extremely large number of genome variants, termed viral quasispecies, and nonstandard viral genomes, which include copy-back viral genomes, deletion viral genomes, mini viral RNAs, and hypermutated RNAs. At the particle level, RNA virus populations are composed of pleomorphic particles, particles missing or having additional genomes, and single particles or particle aggregates. As we continue discovering more about the components of negative-sense RNA virus populations and their crucial functions during virus infection, it will become more important to study RNA virus populations as a whole rather than their individual parts. In this review, we will discuss what is known about the components of negative-sense RNA virus communities, speculate how the components of the virus community interact, and summarize what vaccines and antiviral therapies are being currently developed to target or harness these components.
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17
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Morales-Arce AY, Johri P, Jensen JD. Inferring the distribution of fitness effects in patient-sampled and experimental virus populations: two case studies. Heredity (Edinb) 2022; 128:79-87. [PMID: 34987185 PMCID: PMC8728706 DOI: 10.1038/s41437-021-00493-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 12/12/2021] [Accepted: 12/13/2021] [Indexed: 11/19/2022] Open
Abstract
We here propose an analysis pipeline for inferring the distribution of fitness effects (DFE) from either patient-sampled or experimentally-evolved viral populations, that explicitly accounts for non-Wright-Fisher and non-equilibrium population dynamics inherent to pathogens. We examine the performance of this approach via extensive power and performance analyses, and highlight two illustrative applications - one from an experimentally-passaged RNA virus, and the other from a clinically-sampled DNA virus. Finally, we discuss how such DFE inference may shed light on major research questions in virus evolution, ranging from a quantification of the population genetic processes governing genome size, to the role of Hill-Robertson interference in dictating adaptive outcomes, to the potential design of novel therapeutic approaches to eradicate within-patient viral populations via induced mutational meltdown.
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Affiliation(s)
- Ana Y. Morales-Arce
- grid.215654.10000 0001 2151 2636Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ USA
| | - Parul Johri
- grid.215654.10000 0001 2151 2636Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ USA
| | - Jeffrey D. Jensen
- grid.215654.10000 0001 2151 2636Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ USA
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18
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Robb NC. Virus morphology: Insights from super-resolution fluorescence microscopy. Biochim Biophys Acta Mol Basis Dis 2022; 1868:166347. [PMID: 35032594 PMCID: PMC8755447 DOI: 10.1016/j.bbadis.2022.166347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 01/06/2023]
Abstract
As epitomised by the COVID-19 pandemic, diseases caused by viruses are one of the greatest health and economic burdens to human society. Viruses are ‘nanostructures’, and their small size (typically less than 200 nm in diameter) can make it challenging to obtain images of their morphology and structure. Recent advances in fluorescence microscopy have given rise to super-resolution techniques, which have enabled the structure of viruses to be visualised directly at a resolution in the order of 20 nm. This mini-review discusses how recent state-of-the-art super-resolution imaging technologies are providing new nanoscale insights into virus structure.
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Affiliation(s)
- Nicole C Robb
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom.
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19
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Kuppan JP, Mitrovich MD, Vahey MD. A morphological transformation in respiratory syncytial virus leads to enhanced complement deposition. eLife 2021; 10:70575. [PMID: 34586067 PMCID: PMC8480979 DOI: 10.7554/elife.70575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 09/14/2021] [Indexed: 12/26/2022] Open
Abstract
The complement system is a critical host defense against infection, playing a protective role that can also enhance disease if dysregulated. Although many consequences of complement activation during viral infection are well established, mechanisms that determine the extent to which viruses activate complement remain elusive. Here, we investigate complement activation by human respiratory syncytial virus (RSV), a filamentous respiratory pathogen that causes significant morbidity and mortality. By engineering a strain of RSV harboring tags on the surface glycoproteins F and G, we are able to monitor opsonization of single RSV particles using fluorescence microscopy. These experiments reveal an antigenic hierarchy, where antibodies that bind toward the apex of F in either the pre- or postfusion conformation activate the classical pathway whereas other antibodies do not. Additionally, we identify an important role for virus morphology in complement activation: as viral filaments age, they undergo a morphological transformation which lowers the threshold for complement deposition through changes in surface curvature. Collectively, these results identify antigenic and biophysical characteristics of virus particles that contribute to the formation of viral immune complexes, and suggest models for how these factors may shape disease severity and adaptive immune responses to RSV.
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Affiliation(s)
- Jessica P Kuppan
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, United States
| | - Margaret D Mitrovich
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, United States
| | - Michael D Vahey
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, United States
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20
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Stadtmueller MN, Bhatia S, Kiran P, Hilsch M, Reiter-Scherer V, Adam L, Parshad B, Budt M, Klenk S, Sellrie K, Lauster D, Seeberger PH, Hackenberger CPR, Herrmann A, Haag R, Wolff T. Evaluation of Multivalent Sialylated Polyglycerols for Resistance Induction in and Broad Antiviral Activity against Influenza A Viruses. J Med Chem 2021; 64:12774-12789. [PMID: 34432457 DOI: 10.1021/acs.jmedchem.1c00794] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of multivalent sialic acid-based inhibitors active against a variety of influenza A virus (IAV) strains has been hampered by high genetic and structural variability of the targeted viral hemagglutinin (HA). Here, we addressed this challenge by employing sialylated polyglycerols (PGs). Efficacy of prototypic PGs was restricted to a narrow spectrum of IAV strains. To understand this restriction, we selected IAV mutants resistant to a prototypic multivalent sialylated PG by serial passaging. Resistance mutations mapped to the receptor binding site of HA, which was accompanied by altered receptor binding profiles of mutant viruses as detected by glycan array analysis. Specifying the inhibitor functionalization to 2,6-α-sialyllactose (SL) and adjusting the linker yielded a rationally designed inhibitor covering an extended spectrum of inhibited IAV strains. These results highlight the importance of integrating virological data with chemical synthesis and structural data for the development of sialylated PGs toward broad anti-influenza compounds.
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Affiliation(s)
- Marlena N Stadtmueller
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353 Berlin, Germany
| | - Sumati Bhatia
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Pallavi Kiran
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Malte Hilsch
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Valentin Reiter-Scherer
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Lutz Adam
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle Strasse 10, 13125 Berlin, Germany.,Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor Str. 2, 12489 Berlin, Germany
| | - Badri Parshad
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Matthias Budt
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353 Berlin, Germany
| | - Simon Klenk
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle Strasse 10, 13125 Berlin, Germany.,Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor Str. 2, 12489 Berlin, Germany
| | - Katrin Sellrie
- Department for Biomolecular Systems, Max Planck Institute for Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Daniel Lauster
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.,Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Peter H Seeberger
- Department for Biomolecular Systems, Max Planck Institute for Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Christian P R Hackenberger
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle Strasse 10, 13125 Berlin, Germany
| | - Andreas Herrmann
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Rainer Haag
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Thorsten Wolff
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353 Berlin, Germany
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21
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Pomorski A, Krężel A. Biarsenical fluorescent probes for multifunctional site-specific modification of proteins applicable in life sciences: an overview and future outlook. Metallomics 2021; 12:1179-1207. [PMID: 32658234 DOI: 10.1039/d0mt00093k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Fluorescent modification of proteins of interest (POI) in living cells is desired to study their behaviour and functions in their natural environment. In a perfect setting it should be easy to perform, inexpensive, efficient and site-selective. Although multiple chemical and biological methods have been developed, only a few of them are applicable for cellular studies thanks to their appropriate physical, chemical and biological characteristics. One such successful system is a tetracysteine tag/motif and its selective biarsenical binders (e.g. FlAsH and ReAsH). Since its discovery in 1998 by Tsien and co-workers, this method has been enhanced and revolutionized in terms of its efficiency, formed complex stability and breadth of application. Here, we overview the whole field of knowledge, while placing most emphasis on recent reports. We showcase the improvements of classical biarsenical probes with various optical properties as well as multifunctional molecules that add new characteristics to proteins. We also present the evolution of affinity tags and motifs of biarsenical probes demonstrating much more possibilities in cellular applications. We summarize protocols and reported observations so both beginners and advanced users of biarsenical probes can troubleshoot their experiments. We address the concerns regarding the safety of biarsenical probe application. We showcase examples in virology, studies on receptors or amyloid aggregation, where application of biarsenical probes allowed observations that previously were not possible. We provide a summary of current applications ranging from bioanalytical sciences to allosteric control of selected proteins. Finally, we present an outlook to encourage more researchers to use these magnificent probes.
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Affiliation(s)
- Adam Pomorski
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland.
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22
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Overeem NJ, van der Vries E, Huskens J. A Dynamic, Supramolecular View on the Multivalent Interaction between Influenza Virus and Host Cell. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2007214. [PMID: 33682339 DOI: 10.1002/smll.202007214] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/11/2021] [Indexed: 06/12/2023]
Abstract
Understanding how influenza viruses traverse the mucus and recognize host cells is critical for evaluating their zoonotic potential, and for prevention and treatment of the disease. The surface of the influenza A virus is covered with the receptor-binding protein hemagglutinin and the receptor-cleaving enzyme neuraminidase, which jointly control the interactions between the virus and the host cell. These proteins are organized in closely spaced trimers and tetramers to facilitate multivalent interactions with sialic acid-terminated glycans. This review shows that the individually weak multivalent interactions of influenza viruses allow superselective binding, virus-induced recruitment of receptors, and the formation of dynamic complexes that facilitate molecular walking. Techniques to measure the avidity and receptor specificity of influenza viruses are reviewed, and the pivotal role of multivalent interactions with their emergent properties in crossing the mucus and entering host cells is discussed. A model is proposed for the initiation of cell entry through virus-induced receptor clustering. The multivalent interactions of influenza viruses are maintained in a dynamic regime by a functional balance between binding and cleaving.
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Affiliation(s)
- Nico J Overeem
- Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Erhard van der Vries
- Royal GD, Arnsbergstraat 7, Deventer, 7418 EZ, The Netherlands
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, Utrecht, 3584CX, The Netherlands
| | - Jurriaan Huskens
- Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
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23
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Li T, Li Z, Deans EE, Mittler E, Liu M, Chandran K, Ivanovic T. The shape of pleomorphic virions determines resistance to cell-entry pressure. Nat Microbiol 2021; 6:617-629. [PMID: 33737748 DOI: 10.1038/s41564-021-00877-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 02/10/2021] [Indexed: 11/09/2022]
Abstract
Many enveloped animal viruses produce a variety of particle shapes, ranging from small spherical to long filamentous types. Characterization of how the shape of the virion affects infectivity has been difficult because the shape is only partially genetically encoded, and most pleomorphic virus structures have no selective advantage in vitro. Here, we apply virus fractionation using low-force sedimentation, as well as antibody neutralization coupled with RNAScope, single-particle membrane fusion experiments and stochastic simulations to evaluate the effects of differently shaped influenza A viruses and influenza viruses pseudotyped with Ebola glycoprotein on the infection of cells. Our results reveal that the shape of the virus particles determines the probability of both virus attachment and membrane fusion when viral glycoprotein activity is compromised. The larger contact interface between a cell and a larger particle offers a greater probability that several active glycoproteins are adjacent to each other and can cooperate to induce membrane merger. Particles with a length of tens of micrometres can fuse even when 95% of the glycoproteins are inactivated. We hypothesize that non-genetically encoded variable particle shapes enable pleomorphic viruses to overcome selective pressure and may enable adaptation to infection of cells by emerging viruses such as Ebola. Our results suggest that therapeutics targeting filamentous virus particles could overcome antiviral drug resistance and immune evasion in pleomorphic viruses.
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Affiliation(s)
- Tian Li
- Biochemistry Department, Brandeis University, Waltham, MA, USA
| | - Zhenyu Li
- Biochemistry Department, Brandeis University, Waltham, MA, USA
| | - Erin E Deans
- Biochemistry Department, Brandeis University, Waltham, MA, USA
| | - Eva Mittler
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Meisui Liu
- Biochemistry Department, Brandeis University, Waltham, MA, USA
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Tijana Ivanovic
- Biochemistry Department, Brandeis University, Waltham, MA, USA.
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24
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Touizer E, Sieben C, Henriques R, Marsh M, Laine RF. Application of Super-Resolution and Advanced Quantitative Microscopy to the Spatio-Temporal Analysis of Influenza Virus Replication. Viruses 2021; 13:233. [PMID: 33540739 PMCID: PMC7912985 DOI: 10.3390/v13020233] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/28/2021] [Accepted: 01/28/2021] [Indexed: 02/07/2023] Open
Abstract
With an estimated three to five million human cases annually and the potential to infect domestic and wild animal populations, influenza viruses are one of the greatest health and economic burdens to our society, and pose an ongoing threat of large-scale pandemics. Despite our knowledge of many important aspects of influenza virus biology, there is still much to learn about how influenza viruses replicate in infected cells, for instance, how they use entry receptors or exploit host cell trafficking pathways. These gaps in our knowledge are due, in part, to the difficulty of directly observing viruses in living cells. In recent years, advances in light microscopy, including super-resolution microscopy and single-molecule imaging, have enabled many viral replication steps to be visualised dynamically in living cells. In particular, the ability to track single virions and their components, in real time, now allows specific pathways to be interrogated, providing new insights to various aspects of the virus-host cell interaction. In this review, we discuss how state-of-the-art imaging technologies, notably quantitative live-cell and super-resolution microscopy, are providing new nanoscale and molecular insights into influenza virus replication and revealing new opportunities for developing antiviral strategies.
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Affiliation(s)
- Emma Touizer
- Division of Infection and Immunity, University College London, London WC1E 6AE, UK;
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; (R.H.); (M.M.)
| | - Christian Sieben
- Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
| | - Ricardo Henriques
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; (R.H.); (M.M.)
- The Francis Crick Institute, London NW1 1AT, UK
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
| | - Mark Marsh
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; (R.H.); (M.M.)
| | - Romain F. Laine
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; (R.H.); (M.M.)
- The Francis Crick Institute, London NW1 1AT, UK
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25
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Overeem NJ, Hamming PHE, Grant OC, Di Iorio D, Tieke M, Bertolino MC, Li Z, Vos G, de Vries RP, Woods RJ, Tito NB, Boons GJPH, van der Vries E, Huskens J. Hierarchical Multivalent Effects Control Influenza Host Specificity. ACS CENTRAL SCIENCE 2020; 6:2311-2318. [PMID: 33376792 PMCID: PMC7760459 DOI: 10.1021/acscentsci.0c01175] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Indexed: 05/15/2023]
Abstract
Understanding how emerging influenza viruses recognize host cells is critical in evaluating their zoonotic potential, pathogenicity, and transmissibility between humans. The surface of the influenza virus is covered with hemagglutinin (HA) proteins that can form multiple interactions with sialic acid-terminated glycans on the host cell surface. This multivalent binding affects the selectivity of the virus in ways that cannot be predicted from the individual receptor-ligand interactions alone. Here, we show that the intrinsic structural and energetic differences between the interactions of avian- or human-type receptors with influenza HA translate from individual site affinity and orientation through receptor length and density on the surface into virus avidity and specificity. We introduce a method to measure virus avidity using receptor density gradients. We found that influenza viruses attached stably to a surface at receptor densities that correspond to a minimum number of approximately 8 HA-glycan interactions, but more interactions were required if the receptors were short and human-type. Thus, the avidity and specificity of influenza viruses for a host cell depend not on the sialic acid linkage alone but on a combination of linkage and the length and density of receptors on the cell surface. Our findings suggest that threshold receptor densities play a key role in virus tropism, which is a predicting factor for both their virulence and zoonotic potential.
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Affiliation(s)
- Nico J. Overeem
- Molecular
Nanofabrication Group, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - P. H. Erik Hamming
- Molecular
Nanofabrication Group, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Oliver C. Grant
- Complex
Carbohydrate Research Center, University
of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United
States
| | - Daniele Di Iorio
- Molecular
Nanofabrication Group, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Malte Tieke
- Division
of Virology, Department of Infectious Diseases and Immunology, Faculty
of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
| | - M. Candelaria Bertolino
- Molecular
Nanofabrication Group, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Zeshi Li
- Department
of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical
Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Gaël Vos
- Department
of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical
Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Robert P. de Vries
- Department
of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical
Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Robert J. Woods
- Complex
Carbohydrate Research Center, University
of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United
States
- E-mail:
| | - Nicholas B. Tito
- Electric
Ant Lab, Science Park
106, 1098 XG Amsterdam, The Netherlands
| | - Geert-Jan P. H. Boons
- Complex
Carbohydrate Research Center, University
of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United
States
- Department
of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical
Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands
- Bijvoet Center
for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
- E-mail:
| | - Erhard van der Vries
- Division
of Virology, Department of Infectious Diseases and Immunology, Faculty
of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
- Royal
GD, Arnsbergstraat 7, 7418 EZ Deventer, The Netherlands
- Department
of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
- E-mail:
| | - Jurriaan Huskens
- Molecular
Nanofabrication Group, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
- E-mail:
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26
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Suomalainen M, Prasad V, Kannan A, Greber UF. Cell-to-cell and genome-to-genome variability of adenovirus transcription tuned by the cell cycle. J Cell Sci 2020; 134:jcs252544. [PMID: 32917739 DOI: 10.1242/jcs.252544] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/27/2020] [Indexed: 12/11/2022] Open
Abstract
In clonal cultures, not all cells are equally susceptible to virus infection, and the mechanisms underlying this are poorly understood. Here, we developed image-based single-cell measurements to scrutinize the heterogeneity of adenovirus (AdV) infection. AdV delivers, transcribes and replicates a linear double-stranded DNA genome in the nucleus. We measured the abundance of viral transcripts using single-molecule RNA fluorescence in situ hybridization (FISH) and the incoming 5-ethynyl-2'-deoxycytidine (EdC)-tagged viral genomes using a copper(I)-catalyzed azide-alkyne cycloaddition (click) reaction. Surprisingly, expression of the immediate early gene E1A only moderately correlated with the number of viral genomes in the cell nucleus. Intranuclear genome-to-genome heterogeneity was found at the level of viral transcription and, in accordance, individual genomes exhibited heterogeneous replication activity. By analyzing the cell cycle state, we found that G1 cells exhibited the highest E1A gene expression and displayed increased correlation between E1A gene expression and viral genome copy numbers. The combined image-based single-molecule procedures described here are ideally suited to explore the cell-to-cell variability in viral gene expression in a range of different settings, including the innate immune response.
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Affiliation(s)
- Maarit Suomalainen
- Department of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Vibhu Prasad
- Department of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Abhilash Kannan
- Department of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Urs F Greber
- Department of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
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27
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Jones JE, Le Sage V, Lakdawala SS. Viral and host heterogeneity and their effects on the viral life cycle. Nat Rev Microbiol 2020; 19:272-282. [PMID: 33024309 PMCID: PMC7537587 DOI: 10.1038/s41579-020-00449-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2020] [Indexed: 02/08/2023]
Abstract
Traditionally, the viral replication cycle is envisioned as a single, well-defined loop with four major steps: attachment and entry into a target cell, replication of the viral genome, maturation of viral proteins and genome packaging into infectious progeny, and egress and dissemination to the next target cell. However, for many viruses, a growing body of evidence points towards extreme heterogeneity in each of these steps. In this Review, we reassess the major steps of the viral replication cycle by highlighting recent advances that show considerable variability during viral infection. First, we discuss heterogeneity in entry receptors, followed by a discussion on error-prone and low-fidelity polymerases and their impact on viral diversity. Next, we cover the implications of heterogeneity in genome packaging and assembly on virion morphology. Last, we explore alternative egress mechanisms, including tunnelling nanotubes and host microvesicles. In summary, we discuss the implications of viral phenotypic, morphological and genetic heterogeneity on pathogenesis and medicine. This Review highlights common themes and unique features that give nuance to the viral replication cycle.
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Affiliation(s)
- Jennifer E Jones
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Valerie Le Sage
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Seema S Lakdawala
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. .,Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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28
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Zheng A, Sun W, Xiong X, Freyn AW, Peukes J, Strohmeier S, Nachbagauer R, Briggs JAG, Krammer F, Palese P. Enhancing Neuraminidase Immunogenicity of Influenza A Viruses by Rewiring RNA Packaging Signals. J Virol 2020; 94:e00742-20. [PMID: 32493826 PMCID: PMC7394900 DOI: 10.1128/jvi.00742-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/01/2020] [Indexed: 01/17/2023] Open
Abstract
Humoral immune protection against influenza virus infection is mediated largely by antibodies against hemagglutinin (HA) and neuraminidase (NA), the two major glycoproteins on the virus surface. While influenza virus vaccination efforts have focused mainly on HA, NA-based immunity has been shown to reduce disease severity and provide heterologous protection. Current seasonal vaccines do not elicit strong anti-NA responses-in part due to the immunodominance of the HA protein. Here, we demonstrate that by swapping the 5' and 3' terminal packaging signals of the HA and NA genomic segments, which contain the RNA promoters, we are able to rescue influenza viruses that express more NA and less HA. Vaccination with formalin-inactivated "rewired" viruses significantly enhances the anti-NA antibody response compared to vaccination with unmodified viruses. Passive transfer of sera from mice immunized with rewired virus vaccines shows better protection against influenza virus challenge. Our results provide evidence that the immunodominance of HA stems in part from its abundance on the viral surface, and that rewiring viral packaging signals-thereby increasing the NA content on viral particles-is a viable strategy for improving the immunogenicity of NA in an influenza virus vaccine.IMPORTANCE Influenza virus infections are a major source of morbidity and mortality worldwide. Increasing evidence highlights neuraminidase as a potential vaccination target. This report demonstrates the efficacy of rewiring influenza virus packaging signals for creating vaccines with more neuraminidase content which provide better neuraminidase (NA)-based protection.
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Affiliation(s)
- Allen Zheng
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Weina Sun
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Xiaoli Xiong
- Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Alec W Freyn
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Julia Peukes
- Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Shirin Strohmeier
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Raffael Nachbagauer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - John A G Briggs
- Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Florian Krammer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Peter Palese
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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29
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Live Visualization of Hemagglutinin Dynamics During Infection by Using a Novel Reporter Influenza A Virus. Viruses 2020; 12:v12060687. [PMID: 32604762 PMCID: PMC7354568 DOI: 10.3390/v12060687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022] Open
Abstract
Live visualization of influenza A virus (IAV) structural proteins during viral infection in cells is highly sought objective to study different aspects of the viral replication cycle. To achieve this, we engineered an IAV to express a Tetra Cysteine tag (TC tag) from hemagglutinin (HA), which allows intracellular labeling of the engineered HA protein with biarsenic dyes and subsequent fluorescence detection. Using such constructs, we rescued a recombinant IAV with TC tag inserted in HA, in A/Puerto Rico/8/1934(H1N1) background (HA-TC). This recombinant HA-TC tag reporter IAV was replication-competent; however, as compared to wild type PR8 IAV, it was attenuated in multicycle replication. We confirmed expression of TC tag and biarsenical labeling of HA by immunofluorescence assay in cells infected with an HA-TC tag reporter IAV. Further, we used this reporter virus to visualize HA expression and translocation in IAV infected cells by live confocal imaging. We also tested the utility of the HA-TC IAV in testing chemical inhibitors of the HA translocation. Overall, HA-TC IAV is a versatile tool that will be useful for studying viral life cycle events, virus-host interactions, and anti-viral testing.
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30
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Hirst JC, Hutchinson EC. Single-particle measurements of filamentous influenza virions reveal damage induced by freezing. J Gen Virol 2020; 100:1631-1640. [PMID: 31553305 DOI: 10.1099/jgv.0.001330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Clinical isolates of influenza virus produce pleiomorphic virions, ranging from small spheres to elongated filaments. The filaments are seemingly adaptive in natural infections, but their basic functional properties are poorly understood and functional studies of filaments often report contradictory results. This may be due to artefactual damage from routine laboratory handling, an issue which has been noted several times without being explored in detail. To determine whether standard laboratory techniques could damage filaments, we used immunofluorescence microscopy to rapidly and reproducibly quantify and characterize the dimensions of filaments. Most of the techniques we tested had minimal impact on filaments, but freezing to -70 °C, a standard storage step before carrying out functional studies on influenza viruses, severely reduced their concentration, median length and the infectivity of the whole virion population. We noted that damage from freezing is likely to have affected most of the functional studies of filaments performed to date, and to address this we show that it can be mitigated by snap-freezing or incorporating the cryoprotectant DMSO. We recommend that functional studies of filaments characterize virion populations prior to analysis to ensure reproducibility, and that they use unfrozen samples if possible and cryoprotectants if not. These basic measures will support the robust functional characterizations of filaments that are required to understand their roles in natural influenza virus infections.
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Affiliation(s)
- Jack C Hirst
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, Scotland, UK
| | - Edward C Hutchinson
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, Scotland, UK
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31
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Morales-Arce AY, Harris RB, Stone AC, Jensen JD. Evaluating the contributions of purifying selection and progeny-skew in dictating within-host Mycobacterium tuberculosis evolution. Evolution 2020; 74:992-1001. [PMID: 32233086 DOI: 10.1111/evo.13954] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/08/2020] [Indexed: 12/28/2022]
Abstract
The within-host evolutionary dynamics of tuberculosis (TB) remain unclear, and underlying biological characteristics render standard population genetic approaches based upon the Wright-Fisher model largely inappropriate. In addition, the compact genome combined with an absence of recombination is expected to result in strong purifying selection effects. Thus, it is imperative to establish a biologically relevant evolutionary framework incorporating these factors in order to enable an accurate study of this important human pathogen. Further, such a model is critical for inferring fundamental evolutionary parameters related to patient treatment, including mutation rates and the severity of infection bottlenecks. We here implement such a model and infer the underlying evolutionary parameters governing within-patient evolutionary dynamics. Results demonstrate that the progeny skew associated with the clonal nature of TB severely reduces genetic diversity and that the neglect of this parameter in previous studies has led to significant mis-inference of mutation rates. As such, our results suggest an underlying de novo mutation rate that is considerably faster than previously inferred, and a progeny distribution differing significantly from Wright-Fisher assumptions. This inference represents a more appropriate evolutionary null model, against which the periodic effects of positive selection, associated with drug-resistance for example, may be better assessed.
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Affiliation(s)
- Ana Y Morales-Arce
- Center for Evolution and Medicine, Arizona State University, Tempe, Arizona, USA
| | - Rebecca B Harris
- Center for Evolution and Medicine, Arizona State University, Tempe, Arizona, USA
| | - Anne C Stone
- Center for Evolution and Medicine, Arizona State University, Tempe, Arizona, USA.,School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, USA
| | - Jeffrey D Jensen
- Center for Evolution and Medicine, Arizona State University, Tempe, Arizona, USA.,School of Life Sciences, Arizona State University, Tempe, Arizona, USA
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32
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Yurdakul C, Avci O, Matlock A, Devaux AJ, Quintero MV, Ozbay E, Davey RA, Connor JH, Karl WC, Tian L, Ünlü MS. High-Throughput, High-Resolution Interferometric Light Microscopy of Biological Nanoparticles. ACS NANO 2020; 14:2002-2013. [PMID: 32003974 DOI: 10.1021/acsnano.9b08512] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Label-free, visible light microscopy is an indispensable tool for studying biological nanoparticles (BNPs). However, conventional imaging techniques have two major challenges: (i) weak contrast due to low-refractive-index difference with the surrounding medium and exceptionally small size and (ii) limited spatial resolution. Advances in interferometric microscopy have overcome the weak contrast limitation and enabled direct detection of BNPs, yet lateral resolution remains as a challenge in studying BNP morphology. Here, we introduce a wide-field interferometric microscopy technique augmented by computational imaging to demonstrate a 2-fold lateral resolution improvement over a large field-of-view (>100 × 100 μm2), enabling simultaneous imaging of more than 104 BNPs at a resolution of ∼150 nm without any labels or sample preparation. We present a rigorous vectorial-optics-based forward model establishing the relationship between the intensity images captured under partially coherent asymmetric illumination and the complex permittivity distribution of nanoparticles. We demonstrate high-throughput morphological visualization of a diverse population of Ebola virus-like particles and a structurally distinct Ebola vaccine candidate. Our approach offers a low-cost and robust label-free imaging platform for high-throughput and high-resolution characterization of a broad size range of BNPs.
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Affiliation(s)
- Celalettin Yurdakul
- Department of Electrical and Computer Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - Oguzhan Avci
- Department of Electrical and Computer Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - Alex Matlock
- Department of Electrical and Computer Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - Alexander J Devaux
- Department of Microbiology and National Infectious Diseases Laboratories , Boston University School of Medicine , Boston , Massachusetts 02118 , United States
| | - Maritza V Quintero
- Department of Biochemistry and Structural Biology , University of Texas Health San Antonio , San Antonio , Texas 78229 , United States
| | - Ekmel Ozbay
- Department of Electrical and Electronics Engineering , Bilkent University , 06800 Ankara , Turkey
| | - Robert A Davey
- Department of Microbiology and National Infectious Diseases Laboratories , Boston University School of Medicine , Boston , Massachusetts 02118 , United States
| | - John H Connor
- Department of Microbiology and National Infectious Diseases Laboratories , Boston University School of Medicine , Boston , Massachusetts 02118 , United States
| | - W Clem Karl
- Department of Electrical and Computer Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - Lei Tian
- Department of Electrical and Computer Engineering , Boston University , Boston , Massachusetts 02215 , United States
| | - M Selim Ünlü
- Department of Electrical and Computer Engineering , Boston University , Boston , Massachusetts 02215 , United States
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33
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Jiang W, Ma P, Deng L, Liu Z, Wang X, Liu X, Long G. Hepatitis A virus structural protein pX interacts with ALIX and promotes the secretion of virions and foreign proteins through exosome-like vesicles. J Extracell Vesicles 2020; 9:1716513. [PMID: 32082513 PMCID: PMC7006762 DOI: 10.1080/20013078.2020.1716513] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 01/01/2020] [Accepted: 01/07/2020] [Indexed: 12/12/2022] Open
Abstract
Hepatitis A virus (HAV), a classic nonenveloped virus, has recently been found to be released mainly in the form of quasi-enveloped HAV (eHAV) by hijacking host endosomal sorting complexes required for transport (ESCRT) complexes. Unlike the nonenveloped virion, eHAV contains the viral protein pX on the surface of the HAV capsid as an extension of VP1. How HAV capsids acquire the host envelope and whether the pX protein is involved in this process were previously unknown. Here, we analyse the role of pX in foreign protein secretion in exosome-like extracellular vesicles (EVs) and the formation of eHAV. Fusion of pX to eGFP guided eGFP into exosome-like EVs through directing eGFP into multivesicular bodies (MVBs), and apoptosis-linked gene 2-interacting protein X (ALIX) release was significantly enhanced. Coimmunoprecipitation (co-IP) demonstrated the interaction between pX and the ALIX V domain. Removal of the C-terminal half of pX abolished eHAV release and reduced the interaction between the HAV virion and ALIX. Finally, the C-terminal half of pX alone was sufficient for loading eGFP into EVs by interacting with ALIX. In conclusion, the C-terminal part of pX is important for eHAV production and may have potential for large protein complex loading into exosome-like EVs for therapeutic purposes.
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Affiliation(s)
- Wang Jiang
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Beijing, China
| | - Pengjuan Ma
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Libin Deng
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Zhi Liu
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,Biological Imaging and Instrumental Analysis Center, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Xu Wang
- Department of Electron-microscopy, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China
| | - Xiyu Liu
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Gang Long
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
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34
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Amphipathic Helices of Cellular Proteins Can Replace the Helix in M2 of Influenza A Virus with Only Small Effects on Virus Replication. J Virol 2020; 94:JVI.01605-19. [PMID: 31694941 DOI: 10.1128/jvi.01605-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/04/2019] [Indexed: 11/20/2022] Open
Abstract
M2 of influenza virus functions as a proton channel during virus entry. In addition, an amphipathic helix in its cytoplasmic tail plays a role during budding. It targets M2 to the assembly site where it inserts into the inner membrane leaflet to induce curvature that causes virus scission. Since vesicularization of membranes can be performed by a variety of amphiphilic peptides, we used reverse genetics to investigate whether the peptides can substitute for M2's helix. Virus could not be generated if M2's helix was deleted or replaced by a peptide predicted not to form an amphiphilic helix. In contrast, viruses could be rescued if the M2 helix was exchanged by helices known to induce membrane curvature. Infectious virus titers were marginally reduced if M2 contains the helix of the amphipathic lipid packing sensor from the Epsin N-terminal homology domain or the nonnatural membrane inducer RW16. Transmission electron microscopy of infected cells did not reveal unequivocal evidence that virus budding or membrane scission was disturbed in any of the mutants. Instead, individual virus mutants exhibit other defects in M2, such as reduced surface expression, incorporation into virus particles, and ion channel activity. The protein composition and specific infectivity were also altered for mutant virions. We conclude that the presence of an amphiphilic helix in M2 is essential for virus replication but that other helices can replace its basic (curvature-inducing) function.IMPORTANCE Influenza virus is unique among enveloped viruses since it does not rely on the cellular ESCRT machinery for budding. Instead, viruses encode their own scission machine, the M2 protein. M2 is targeted to the edge of the viral assembly site, where it inserts an amphiphilic helix into the membrane to induce curvature. Cellular proteins utilize a similar mechanism for scission of vesicles. We show that the helix of M2 can be replaced by helices from cellular proteins with only small effects on virus replication. No evidence was obtained that budding is disturbed, but individual mutants exhibit other defects in M2 that explain the reduced virus titers. In contrast, no virus could be generated if the helix of M2 is deleted or replaced by irrelevant sequences. These experiments support the concept that M2 requires an amphiphilic helix to induce membrane curvature, but its biophysical properties are more important than the amino acid sequence.
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35
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Gong D, Dai X, Jih J, Liu YT, Bi GQ, Sun R, Zhou ZH. DNA-Packing Portal and Capsid-Associated Tegument Complexes in the Tumor Herpesvirus KSHV. Cell 2019; 178:1329-1343.e12. [PMID: 31447177 PMCID: PMC6753055 DOI: 10.1016/j.cell.2019.07.035] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/16/2019] [Accepted: 07/17/2019] [Indexed: 01/07/2023]
Abstract
Assembly of Kaposi's sarcoma-associated herpesvirus (KSHV) begins at a bacteriophage-like portal complex that nucleates formation of an icosahedral capsid with capsid-associated tegument complexes (CATCs) and facilitates translocation of an ∼150-kb dsDNA genome, followed by acquisition of a pleomorphic tegument and envelope. Because of deviation from icosahedral symmetry, KSHV portal and tegument structures have largely been obscured in previous studies. Using symmetry-relaxed cryo-EM, we determined the in situ structure of the KSHV portal and its interactions with surrounding capsid proteins, CATCs, and the terminal end of KSHV's dsDNA genome. Our atomic models of the portal and capsid/CATC, together with visualization of CATCs' variable occupancy and alternate orientation of CATC-interacting vertex triplexes, suggest a mechanism whereby the portal orchestrates procapsid formation and asymmetric long-range determination of CATC attachment during DNA packaging prior to pleomorphic tegumentation/envelopment. Structure-based mutageneses confirm that a triplex deep binding groove for CATCs is a hotspot that holds promise for antiviral development.
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Affiliation(s)
- Danyang Gong
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Xinghong Dai
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jonathan Jih
- California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yun-Tao Liu
- California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, USA; Center for Integrative Imaging, Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China (USTC), Hefei, Anhui 230026, China
| | - Guo-Qiang Bi
- Center for Integrative Imaging, Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China (USTC), Hefei, Anhui 230026, China
| | - Ren Sun
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Z Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, USA.
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36
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Ghorbani A, Ngunjiri JM, Lee CW. Influenza A Virus Subpopulations and Their Implication in Pathogenesis and Vaccine Development. Annu Rev Anim Biosci 2019; 8:247-267. [PMID: 31479617 DOI: 10.1146/annurev-animal-021419-083756] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The concept of influenza A virus (IAV) subpopulations emerged approximately 75 years ago, when Preben von Magnus described "incomplete" virus particles that interfere with the replication of infectious virus. It is now widely accepted that infectious particles constitute only a minor portion of biologically active IAV subpopulations. The IAV quasispecies is an extremely diverse swarm of biologically and genetically heterogeneous particle subpopulations that collectively influence the evolutionary fitness of the virus. This review summarizes the current knowledge of IAV subpopulations, focusing on their biologic and genomic diversity. It also discusses the potential roles IAV subpopulations play in virus pathogenesis and live attenuated influenza vaccine development.
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Affiliation(s)
- Amir Ghorbani
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio 44691, USA; , , .,Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210, USA
| | - John M Ngunjiri
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio 44691, USA; , ,
| | - Chang-Won Lee
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio 44691, USA; , , .,Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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37
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Cholesterol Binding to the Transmembrane Region of a Group 2 Hemagglutinin (HA) of Influenza Virus Is Essential for Virus Replication, Affecting both Virus Assembly and HA Fusion Activity. J Virol 2019; 93:JVI.00555-19. [PMID: 31118253 DOI: 10.1128/jvi.00555-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/14/2019] [Indexed: 12/21/2022] Open
Abstract
Hemagglutinin (HA) of influenza virus is incorporated into cholesterol-enriched nanodomains of the plasma membrane. Phylogenetic group 2 HAs contain the conserved cholesterol consensus motif (CCM) YKLW in the transmembrane region. We previously reported that mutations in the CCM retarded intracellular transport of HA and decreased its nanodomain association. Here, we analyzed whether cholesterol interacts with the CCM. Incorporation of photocholesterol into HA was significantly reduced if the whole CCM is replaced by alanine, both using immunoprecipitated HA and when HA is embedded in the membrane. We next used reverse genetics to investigate the significance of the CCM for virus replication. No virus was rescued if the whole motif is exchanged (YKLW4A); singly (LA) or doubly (YK2A and LW2A) mutated virus showed decreased titers and a comparative fitness disadvantage. In polarized cells, transport of HA mutants to the apical membrane was not disturbed. Reduced amounts of HA and cholesterol were incorporated into the viral membrane. Mutant viruses exhibit a decrease in hemolysis, which is only partially corrected if the membrane is replenished with cholesterol. More specifically, viruses have a defect in hemifusion, as demonstrated by fluorescence dequenching. Cells expressing HA YKLW4A fuse with erythrocytes, but the number of events is reduced. Even after acidification unfused erythrocytes remain cell bound, a phenomenon not observed with wild-type HA. We conclude that cholesterol binding to a group 2 HA is essential for virus replication. It has pleiotropic effects on virus assembly and membrane fusion, mainly on lipid mixing and possibly a preceding step.IMPORTANCE The glycoprotein HA is a major pathogenicity factor of influenza viruses. Whereas the structure and function of HA's ectodomain is known in great detail, similar data for the membrane-anchoring part of the protein are missing. Here, we demonstrate that the transmembrane region of a group 2 HA interacts with cholesterol, the major lipid of the plasma membrane and the defining element of the viral budding site nanodomains of the plasma membrane. The cholesterol binding motif is essential for virus replication. Its partial removal affects various steps of the viral life cycle, such as assembly of new virus particles and their subsequent cell entry via membrane fusion. A cholesterol binding pocket in group 2 HAs might be a promising target for a small lipophilic drug that inactivates the virus.
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Protein profiling and pseudo-parallel reaction monitoring to monitor a fusion-associated conformational change in hemagglutinin. Anal Bioanal Chem 2019; 411:4987-4998. [PMID: 31254054 DOI: 10.1007/s00216-019-01921-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/08/2019] [Accepted: 05/14/2019] [Indexed: 12/22/2022]
Abstract
Influenza infection requires viral escape from early endosomes into the cytosol, which is enabled by an acid-induced irreversible conformational transformation in the viral protein hemagglutinin. Despite the direct relationship between this conformational change and infectivity, label-free methods for characterizing this and other protein conformational changes in biological mixtures are limited. While the chemical reactivity of the protein backbone and side-chain residues is a proxy for protein conformation, coupling this reactivity to quantitative mass spectrometry is a challenge in complex environments. Herein, we evaluate whether electrophilic amidination coupled with pseudo-parallel reaction monitoring is an effective label-free approach to detect the fusion-associated conformational transformation in recombinant hemagglutinin (rHA). We identified rHA peptides that are differentially amidinated between the pre- and post-fusion states, and validated that this difference relies upon the fusion-associated conformational switch. We further demonstrate that we can distinguish the fusion profile in a matrix of digested cellular lysate. This fusion assay can be used to evaluate fusion competence for modified HA. Graphical abstract.
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Lakdawala SS, Lee N, Brooke CB. Teaching an Old Virus New Tricks: A Review on New Approaches to Study Age-Old Questions in Influenza Biology. J Mol Biol 2019; 431:4247-4258. [PMID: 31051174 DOI: 10.1016/j.jmb.2019.04.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/12/2019] [Accepted: 04/23/2019] [Indexed: 01/31/2023]
Abstract
Influenza viruses have been studied for over 80 years, yet much about the basic viral lifecycle remain unknown. However, new imaging, biochemical, and sequencing techniques have revealed significant insight into many age-old questions of influenza virus biology. In this review, we will cover the role of imaging techniques to describe unique aspects of influenza virus assembly, biochemical techniques to study viral genomic organization, and next-generation sequencing to explore influenza genomic evolution. Our goal is to provide a brief overview of how emerging techniques are being used to answer basic questions about influenza viruses. This is not a comprehensive list of emerging techniques, rather ones that we feel will continue to make significant contributions to field of influenza biology.
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Affiliation(s)
- Seema S Lakdawala
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, School of Medicine Pittsburgh, PA 15219, USA.
| | - Nara Lee
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, School of Medicine Pittsburgh, PA 15219, USA.
| | - Christopher B Brooke
- Department of Microbiology, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USA.
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RNA Sequence Features Are at the Core of Influenza A Virus Genome Packaging. J Mol Biol 2019; 431:4217-4228. [PMID: 30914291 DOI: 10.1016/j.jmb.2019.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 02/18/2019] [Accepted: 03/11/2019] [Indexed: 11/23/2022]
Abstract
The influenza A virus (IAV), a respiratory pathogen for humans, poses serious medical and economic challenges to global healthcare systems. The IAV genome, consisting of eight single-stranded viral RNA segments, is incorporated into virions by a complex process known as genome packaging. Specific RNA sequences within the viral RNA segments serve as signals that are necessary for genome packaging. Although efficient packaging is a prerequisite for viral infectivity, many of the mechanistic details about this process are still missing. In this review, we discuss the recent advances toward the understanding of IAV genome packaging and focus on the RNA features that play a role in this process.
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Abstract
Morphological variation is a common yet poorly understood feature of influenza virus populations. Vahey and Fletcher reveal that the production of physically and phenotypically heterogeneous particles is an inherent feature of the influenza assembly process that may promote virus survival in challenging environments.
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Affiliation(s)
- Brigitte E Martin
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Christopher B Brooke
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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A rainbow of influenza virions. Nat Rev Microbiol 2018; 17:64-65. [PMID: 30546112 DOI: 10.1038/s41579-018-0135-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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