1
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Kosik I, Da Silva Santos J, Angel M, Hu Z, Holly J, Gibbs JS, Gill T, Kosikova M, Li T, Bakhache W, Dolan PT, Xie H, Andrews SF, Gillespie RA, Kanekiyo M, McDermott AB, Pierson TC, Yewdell JW. C1q enables influenza hemagglutinin stem binding antibodies to block viral attachment and broadens the antibody escape repertoire. Sci Immunol 2024; 9:eadj9534. [PMID: 38517951 DOI: 10.1126/sciimmunol.adj9534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 02/14/2024] [Indexed: 03/24/2024]
Abstract
Antigenic drift, the gradual accumulation of amino acid substitutions in the influenza virus hemagglutinin (HA) receptor protein, enables viral immune evasion. Antibodies (Abs) specific for the drift-resistant HA stem region are a promising universal influenza vaccine target. Although anti-stem Abs are not believed to block viral attachment, here we show that complement component 1q (C1q), a 460-kilodalton protein with six Ab Fc-binding domains, confers attachment inhibition to anti-stem Abs and enhances their fusion and neuraminidase inhibition. As a result, virus neutralization activity in vitro is boosted up to 30-fold, and in vivo protection from influenza PR8 infection in mice is enhanced. These effects reflect increased steric hindrance and not increased Ab avidity. C1q greatly expands the anti-stem Ab viral escape repertoire to include residues throughout the HA, some of which cause antigenic alterations in the globular region or modulate HA receptor avidity. We also show that C1q enhances the neutralization activity of non-receptor binding domain anti-SARS-CoV-2 spike Abs, an effect dependent on spike density on the virion surface. These findings demonstrate that C1q can greatly expand Ab function and thereby contribute to viral evolution and immune escape.
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Affiliation(s)
- Ivan Kosik
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Jefferson Da Silva Santos
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Mathew Angel
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Zhe Hu
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Jaroslav Holly
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - James S Gibbs
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Tanner Gill
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Martina Kosikova
- Laboratory of Respiratory Viral Diseases, Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Tiansheng Li
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - William Bakhache
- Quantitative Virology and Evolution Unit, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Patrick T Dolan
- Quantitative Virology and Evolution Unit, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Hang Xie
- Laboratory of Respiratory Viral Diseases, Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Sarah F Andrews
- Vaccine Immunology Program, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rebecca A Gillespie
- Molecular Immunoengineering Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Masaru Kanekiyo
- Molecular Immunoengineering Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Adrian B McDermott
- Vaccine Immunology Program, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Theodore C Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Jonathan W Yewdell
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
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2
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Pushan SS, Samantaray M, Rajagopalan M, Ramaswamy A. Structural dynamics of influenza A (H1N1) hemagglutinin protein: a comparative study of Indian (2018) isolate with its evolutionary neighbor, Californian (2009) strain. J Biomol Struct Dyn 2024:1-14. [PMID: 38379377 DOI: 10.1080/07391102.2024.2317985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/07/2024] [Indexed: 02/22/2024]
Abstract
This work highlights the structure and dynamics of two trimeric HA proteins of the H1N1 virus from different origins, the pandemic Californian (HACal) and its closest Indian neighbor (HAInd), reported in 2009 and 2018, respectively. Because of mutation, HAInd acquires new N-glycosylation and epitope binding sites along with mutations at RBD, which might trigger an altered viral-host interaction mechanism. Molecular dynamics simulations performed on HA trimers for a period of 250 ns reveal the highly dynamic nature of HACal trimers inherited by the flexibility of HA monomers. In the trimer, the dynamics of one monomer are more pronounced compared to others, and the enhanced dynamics of RBD especially gain attention as they plays a key role during fusion. Conversely, the mutant HAInd trimer effectively establishes more H-bond interactions, and accordingly, the trimer undergoes more stabilized dynamics with a relatively lower amplitude of RBD dynamics, as endorsed by the reduced RMSD, Rg, and SASA variations. The cooperative and anti-cooperative motions dissected for the subdomains of both strains also reveal a prominent anticorrelative motion of RBD against other subdomains. In agreement, the free energy landscape of stable HAInd is also characterized by a single lowest wide energy basin instead of the two minimum energy basins of the HACal trimer. In essence, the mutant HAInd acquires a highly stable conformation with novel functional features, which calls for (i) further investigation on the emerging mutation-mediated variation in viral-host binding mechanism and (ii) the need for further design of site-specific potential inhibitors to face future challenges.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Shilpa Sri Pushan
- Department of Bioinformatics, Pondicherry University (A Central University), Kalapet, Puducherry, India
| | - Mahesh Samantaray
- Department of Bioinformatics, Pondicherry University (A Central University), Kalapet, Puducherry, India
| | - Muthukumaran Rajagopalan
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur
| | - Amutha Ramaswamy
- Department of Bioinformatics, Pondicherry University (A Central University), Kalapet, Puducherry, India
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3
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Sychla A, Stach CS, Roach SN, Hayward AN, Langlois RA, Smanski MJ. High-throughput investigation of genetic design constraints in domesticated Influenza A Virus for transient gene delivery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580300. [PMID: 38405907 PMCID: PMC10888799 DOI: 10.1101/2024.02.14.580300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Replication-incompetent single cycle infectious Influenza A Virus (sciIAV) has demonstrated utility as a research and vaccination platform. Protein-based therapeutics are increasingly attractive due to their high selectivity and potent efficacy but still suffer from low bioavailability and high manufacturing cost. Transient RNA-mediated delivery is a safe alternative that allows for expression of protein-based therapeutics within the target cells or tissues but is limited by delivery efficiency. Here, we develop recombinant sciIAV as a platform for transient gene delivery in vivo and in vitro for therapeutic, research, and manufacturing applications (in vivo antimicrobial production, cell culture contamination clearance, and production of antiviral proteins in vitro). While adapting the system to deliver new protein cargo we discovered expression differences presumably resulting from genetic context effects. We applied a high-throughput screen to map these within the 3'-untranslated and coding regions of the hemagglutinin-encoding segment 4. This screen revealed permissible mutations in the 3'-UTR and depletion of RNA level motifs in the N-terminal coding region.
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Affiliation(s)
- Adam Sychla
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Biotechnology Institute, University of Minnesota, Saint Paul, MN 55108
| | - Christopher S Stach
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Biotechnology Institute, University of Minnesota, Saint Paul, MN 55108
| | - Shanley N Roach
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Department of Microbiology and Immunology, University of Minnesota, Saint Paul, MN 55108
| | - Amanda N Hayward
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Biotechnology Institute, University of Minnesota, Saint Paul, MN 55108
| | - Ryan A Langlois
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Department of Microbiology and Immunology, University of Minnesota, Saint Paul, MN 55108
| | - Michael J Smanski
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Biotechnology Institute, University of Minnesota, Saint Paul, MN 55108
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4
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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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5
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Rice A, Zimmerberg J, Pastor RW. Initiation and evolution of pores formed by influenza fusion peptides probed by lysolipid inclusion. Biophys J 2023; 122:1018-1032. [PMID: 36575795 PMCID: PMC10111278 DOI: 10.1016/j.bpj.2022.12.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/09/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
The fusion peptide (FP) domain is necessary for the fusogenic activity of spike proteins in a variety of enveloped viruses, allowing the virus to infect the host cell, and is the only part of the protein that interacts directly with the target membrane lipid tails during fusion. There are consistent findings of poration by this domain in experimental model membrane systems, and, in certain conditions, the isolated FPs can generate pores. Here, we use molecular dynamics simulations to investigate the specifics of how these FP-induced pores form in membranes with different compositions of lysolipid and POPC. The simulations show that pores form spontaneously at high lysolipid concentrations via hybrid intermediates, where FP aggregates in the cis leaflet tilt to form a funnel-like structure that spans the leaflet and locally reduces the hydrophobic thickness that must be traversed by water to form a pore. By restraining a single FP within an FP aggregate to this tilted conformation, pores can be formed in lower-lysolipid-content membranes, including pure POPC, on the 100-ns timescale, much more rapidly than in unbiased simulations in bilayers with the same composition. The pore formation pathway is similar to the spontaneous formation in high lysolipid concentrations. Depending on the membrane composition, the pores can be metastable (as seen in POPC) or lead to membrane rupture.
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Affiliation(s)
- Amy Rice
- Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland.
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6
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Rice A, Haldar S, Wang E, Blank PS, Akimov SA, Galimzyanov TR, Pastor RW, Zimmerberg J. Planar aggregation of the influenza viral fusion peptide alters membrane structure and hydration, promoting poration. Nat Commun 2022; 13:7336. [PMID: 36470871 PMCID: PMC9722698 DOI: 10.1038/s41467-022-34576-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/28/2022] [Indexed: 12/07/2022] Open
Abstract
To infect, enveloped viruses employ spike protein, spearheaded by its amphipathic fusion peptide (FP), that upon activation extends out from the viral surface to embed into the target cellular membrane. Here we report that synthesized influenza virus FPs are membrane active, generating pores in giant unilamellar vesicles (GUV), and thus potentially explain both influenza virus' hemolytic activity and the liposome poration seen in cryo-electron tomography. Experimentally, FPs are heterogeneously distributed on the GUV at the time of poration. Consistent with this heterogeneous distribution, molecular dynamics (MD) simulations of asymmetric bilayers with different numbers of FPs in one leaflet show FP aggregation. At the center of FP aggregates, a profound change in the membrane structure results in thinning, higher water permeability, and curvature. Ultimately, a hybrid bilayer nanodomain forms with one lipidic leaflet and one peptidic leaflet. Membrane elastic theory predicts a reduced barrier to water pore formation when even a dimer of FPs thins the membrane as above, and the FPs of that dimer tilt, to continue the leaflet bending initiated by the hydrophobic mismatch between the FP dimer and the surrounding lipid.
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Affiliation(s)
- Amy Rice
- grid.94365.3d0000 0001 2297 5165Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Sourav Haldar
- grid.94365.3d0000 0001 2297 5165Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA ,grid.418363.b0000 0004 0506 6543Present Address: Division of Virus Research and Therapeutics, CSIR-Central Drug Research Institute, Lucknow, UP India
| | - Eric Wang
- grid.94365.3d0000 0001 2297 5165Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD USA ,grid.94365.3d0000 0001 2297 5165Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Paul S. Blank
- grid.94365.3d0000 0001 2297 5165Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Sergey A. Akimov
- grid.4886.20000 0001 2192 9124A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
| | - Timur R. Galimzyanov
- grid.4886.20000 0001 2192 9124A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia ,grid.35043.310000 0001 0010 3972National University of Science and Technology “MISiS”, 4 Leninskiy Prospect, Moscow, Russia
| | - Richard W. Pastor
- grid.94365.3d0000 0001 2297 5165Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Joshua Zimmerberg
- grid.94365.3d0000 0001 2297 5165Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
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7
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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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8
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ARHGAP1 Transported with Influenza Viral Genome Ensures Integrity of Viral Particle Surface through Efficient Budozone Formation. mBio 2022; 13:e0072122. [PMID: 35475647 PMCID: PMC9239208 DOI: 10.1128/mbio.00721-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Influenza viral particles are assembled at the plasma membrane concomitantly with Rab11a-mediated endocytic transport of viral ribonucleoprotein complexes (vRNPs). The mechanism of spatiotemporal regulation of viral budozone formation and its regulatory molecules on the endocytic vesicles remain unclear. Here, we performed a proximity-based proteomics approach for Rab11a and found that ARHGAP1, a Rho GTPase-activating protein, is transported through the Rab11a-mediated apical transport of vRNP. ARHGAP1 stabilized actin filaments in infected cells for the lateral clustering of hemagglutinin (HA) molecules, a viral surface membrane protein, to the budozone. Disruption of the HA clustering results in the production of virions with low HA content, and such virions were less resistant to protease and had enhanced antigenicity, presumably because reduced clustering of viral membrane proteins exposes hidden surfaces. Collectively, these results demonstrate that Rab11a-mediated endocytic transport of ARHGAP1 with vRNPs stimulates budozone formation to ensure the integrity of virion surface required for viral survival.
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9
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Huang QJ, Song K, Xu C, Bolon DNA, Wang JP, Finberg RW, Schiffer CA, Somasundaran M. Quantitative structural analysis of influenza virus by cryo-electron tomography and convolutional neural networks. Structure 2022; 30:777-786.e3. [PMID: 35290796 PMCID: PMC9610019 DOI: 10.1016/j.str.2022.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/08/2021] [Accepted: 02/17/2022] [Indexed: 01/01/2023]
Abstract
Influenza viruses pose severe public health threats globally. Influenza viruses are extensively pleomorphic, in shape, size, and organization of viral proteins. Analysis of influenza morphology and ultrastructure can help elucidate viral structure-function relationships and aid in therapeutics and vaccine development. While cryo-electron tomography (cryoET) can depict the 3D organization of pleomorphic influenza, the low signal-to-noise ratio inherent to cryoET and viral heterogeneity have precluded detailed characterization of influenza viruses. In this report, we leveraged convolutional neural networks and cryoET to characterize the morphological architecture of the A/Puerto Rico/8/34 (H1N1) influenza strain. Our pipeline improved the throughput of cryoET analysis and accurately identified viral components within tomograms. Using this approach, we successfully characterized influenza morphology, glycoprotein density, and conducted subtomogram averaging of influenza glycoproteins. Application of this processing pipeline can aid in the structural characterization of not only influenza viruses, but other pleomorphic viruses and infected cells.
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Affiliation(s)
- Qiuyu J Huang
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Kangkang Song
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Chen Xu
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Daniel N A Bolon
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Jennifer P Wang
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Robert W Finberg
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA.
| | - Mohan Somasundaran
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA.
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10
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Slater A, Nair N, Suétt R, Mac Donnchadha R, Bamford C, Jasim S, Livingstone D, Hutchinson E. Visualising Viruses. J Gen Virol 2022; 103:001730. [PMID: 35082014 PMCID: PMC8895616 DOI: 10.1099/jgv.0.001730] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/22/2021] [Indexed: 12/28/2022] Open
Abstract
Viruses pose a challenge to our imaginations. They exert a highly visible influence on the world in which we live, but operate at scales we cannot directly perceive and without a clear separation between their own biology and that of their hosts. Communication about viruses is therefore typically grounded in mental images of virus particles. Virus particles, as the infectious stage of the viral replication cycle, can be used to explain many directly observable properties of transmission, infection and immunity. In addition, their often striking beauty can stimulate further interest in virology. The structures of some virus particles have been determined experimentally in great detail, but for many important viruses a detailed description of the virus particle is lacking. This can be because they are challenging to describe with a single experimental method, or simply because of a lack of data. In these cases, methods from medical illustration can be applied to produce detailed visualisations of virus particles which integrate information from multiple sources. Here, we demonstrate how this approach was used to visualise the highly variable virus particles of influenza A viruses and, in the early months of the COVID-19 pandemic, the virus particles of the then newly characterised and poorly described SARS-CoV-2. We show how constructing integrative illustrations of virus particles can challenge our thinking about the biology of viruses, as well as providing tools for science communication, and we provide a set of science communication resources to help visualise two viruses whose effects are extremely apparent to all of us.
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Affiliation(s)
- Annabel Slater
- School of Life Sciences, University of Glasgow, Glasgow, UK
| | - Naina Nair
- School of Simulation and Visualisation, The Glasgow School of Art, Glasgow, UK
| | - Rachael Suétt
- School of Simulation and Visualisation, The Glasgow School of Art, Glasgow, UK
| | | | - Connor Bamford
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
- Present address: Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, Ireland
| | - Seema Jasim
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Daniel Livingstone
- School of Simulation and Visualisation, The Glasgow School of Art, Glasgow, UK
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11
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Flórido M, Chiu J, Hogg PJ. Influenza A Virus Hemagglutinin Is Produced in Different Disulfide-Bonded States. Antioxid Redox Signal 2021; 35:1081-1092. [PMID: 33985344 DOI: 10.1089/ars.2021.0033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Aims: Influenza A virus hemagglutinin (HA) binding to sialic acid on lung epithelial cells triggers membrane fusion and infection. Host thiol isomerases have been shown to play a role in influenza A virus infection, and we hypothesized that this role involved manipulation of disulfide bonds in HA. Results: Analysis of HA crystal structures revealed that three of the six HA disulfides occur in high-energy conformations and four of the six bonds can exist in unformed states, suggesting that the disulfide landscape of HA is generally strained and the bonds may be labile. We measured the redox state of influenza A virus HA disulfide bonds and their susceptibility to cleavage by vascular thiol isomerases. Using differential cysteine alkylation and mass spectrometry, we show that all six HA disulfide bonds exist in unformed states in ∼1 in 10 recombinant and viral surface HA molecules. Four of the six H1 and H3 HA bonds are cleaved by the vascular thiol isomerases, thioredoxin and protein disulphide isomerase, in recombinant proteins, which correlated with surface exposure of the disulfides in crystal structures. In contrast, viral surface HA disulfide bonds are impervious to five different vascular thiol isomerases. Innovation: It has been assumed that the disulfide bonds in mature HA protein are intact and inert. We show that all six HA disulfide bonds can exist in unformed states. Conclusion: These findings indicate that influenza A virus HA disulfides are naturally labile but not substrates for thiol isomerases when expressed on the viral surface.
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Affiliation(s)
- Manuela Flórido
- ACRF Centenary Cancer Research Centre, The Centenary Institute, Camperdown, New South Wales, Australia
| | - Joyce Chiu
- ACRF Centenary Cancer Research Centre, The Centenary Institute, Camperdown, New South Wales, Australia
| | - Philip J Hogg
- ACRF Centenary Cancer Research Centre, The Centenary Institute, Camperdown, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
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12
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Gamblin SJ, Vachieri SG, Xiong X, Zhang J, Martin SR, Skehel JJ. Hemagglutinin Structure and Activities. Cold Spring Harb Perspect Med 2021; 11:a038638. [PMID: 32513673 PMCID: PMC8485738 DOI: 10.1101/cshperspect.a038638] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hemagglutinins (HAs) are the receptor-binding and membrane fusion glycoproteins of influenza viruses. They recognize sialic acid-containing, cell-surface glycoconjugates as receptors but have limited affinity for them, and, as a consequence, virus attachment to cells requires their interaction with several virus HAs. Receptor-bound virus is transferred into endosomes where membrane fusion by HAs is activated at pH between 5 and 6.5, depending on the strain of virus. Fusion activity requires extensive rearrangements in HA conformation that include extrusion of a buried "fusion peptide" to connect with the endosomal membrane, form a bridge to the virus membrane, and eventually bring both membranes close together. In this review, we give an overview of the structures of the 16 genetically and antigenically distinct subtypes of influenza A HA in relation to these two functions in virus replication and in relation to recognition of HA by antibodies that neutralize infection.
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Affiliation(s)
- Steven J Gamblin
- Structural Biology of Disease Processes Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Sébastien G Vachieri
- Structural Biology of Disease Processes Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Xiaoli Xiong
- Structural Biology of Disease Processes Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Jie Zhang
- Structural Biology of Disease Processes Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Stephen R Martin
- Structural Biology of Disease Processes Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - John J Skehel
- Structural Biology of Disease Processes Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
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13
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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: 3] [Impact Index Per Article: 1.0] [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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14
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Guthmiller JJ, Utset HA, Wilson PC. B Cell Responses against Influenza Viruses: Short-Lived Humoral Immunity against a Life-Long Threat. Viruses 2021; 13:965. [PMID: 34067435 PMCID: PMC8224597 DOI: 10.3390/v13060965] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 12/25/2022] Open
Abstract
Antibodies are critical for providing protection against influenza virus infections. However, protective humoral immunity against influenza viruses is limited by the antigenic drift and shift of the major surface glycoproteins, hemagglutinin and neuraminidase. Importantly, people are exposed to influenza viruses throughout their life and tend to reuse memory B cells from prior exposure to generate antibodies against new variants. Despite this, people tend to recall memory B cells against constantly evolving variable epitopes or non-protective antigens, as opposed to recalling them against broadly neutralizing epitopes of hemagglutinin. In this review, we discuss the factors that impact the generation and recall of memory B cells against distinct viral antigens, as well as the immunological limitations preventing broadly neutralizing antibody responses. Lastly, we discuss how next-generation vaccine platforms can potentially overcome these obstacles to generate robust and long-lived protection against influenza A viruses.
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Affiliation(s)
- Jenna J. Guthmiller
- Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA; (H.A.U.); (P.C.W.)
| | - Henry A. Utset
- Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA; (H.A.U.); (P.C.W.)
| | - Patrick C. Wilson
- Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA; (H.A.U.); (P.C.W.)
- Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
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15
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Trexler M, Brusatori M, Auner G. Avidin-biotin complex-based capture coating platform for universal Influenza virus immobilization and characterization. PLoS One 2021; 16:e0247429. [PMID: 33635877 PMCID: PMC7909696 DOI: 10.1371/journal.pone.0247429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/08/2021] [Indexed: 11/18/2022] Open
Abstract
Influenza virus mutates quickly and unpredictably creating emerging pathogenic strains that are difficult to detect, diagnose, and characterize. Conventional tools to study and characterize virus, such as next generation sequencing, genome amplification (RT-PCR), and serological antibody testing, are not adequately suited to rapidly mutating pathogens like Influenza virus where the success of infection heavily depends on the phenotypic expression of surface glycoproteins. Bridging the gap between genome and pathogenic expression remains a challenge. Using sialic acid as a universal Influenza virus binding receptor, a novel virus avidin-biotin complex-based capture coating was developed and characterized that may be used to create future diagnostic and interrogation platforms for viable whole Influenza virus. First, fluorescent FITC probe studies were used to optimize coating component concentrations. Then atomic force microscopy (AFM) was used to profile the surface characteristics of the novel capture coating, acquire topographical imaging of Influenza particles immobilized by the coating, and calculate the capture efficiency of the coating (over 90%) for all four representative human Influenza virus strains tested.
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Affiliation(s)
- Micaela Trexler
- Smart Sensors and Integrated Microsystems, Wayne State University, Detroit, Michigan, United States of America
- Department of Biomedical Engineering, Wayne State University College of Engineering, Detroit, Michigan, United States of America
- * E-mail:
| | - Michelle Brusatori
- Smart Sensors and Integrated Microsystems, Wayne State University, Detroit, Michigan, United States of America
- Department of Biomedical Engineering, Wayne State University College of Engineering, Detroit, Michigan, United States of America
- Michael and Marian Illitch Department of Surgery, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Gregory Auner
- Smart Sensors and Integrated Microsystems, Wayne State University, Detroit, Michigan, United States of America
- Department of Biomedical Engineering, Wayne State University College of Engineering, Detroit, Michigan, United States of America
- Michael and Marian Illitch Department of Surgery, Wayne State University School of Medicine, Detroit, Michigan, United States of America
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16
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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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17
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Abstract
Much of virus fate, both in the environment and in physical/chemical treatment, is dependent on electrostatic interactions. Developing an accurate means of predicting virion isoelectric point (pI) would help to understand and anticipate virus fate and transport, especially for viruses that are not readily propagated in the lab. One simple approach to predicting pI estimates the pH at which the sum of charges from ionizable amino acids in capsid proteins approaches zero. However, predicted pIs based on capsid charges frequently deviate by several pH units from empirically measured pIs. Recently, the discrepancy between empirical and predicted pI was attributed to the electrostatic neutralization of predictable polynucleotide-binding regions (PBRs) of the capsid interior. In this paper, we review models presupposing (i) the influence of the viral polynucleotide on surface charge or (ii) the contribution of only exterior residues to surface charge. We then compare these models to the approach of excluding only PBRs and hypothesize a conceptual electrostatic model that aligns with this approach. The PBR exclusion method outperformed methods based on three-dimensional (3D) structure and accounted for major discrepancies in predicted pIs without adversely affecting pI prediction for a diverse range of viruses. In addition, the PBR exclusion method was determined to be the best available method for predicting virus pI, since (i) PBRs are predicted independently of the impact on pI, (ii) PBR prediction relies on proteome sequences rather than detailed structural models, and (iii) PBR exclusion was successfully demonstrated on a diverse set of viruses. These models apply to nonenveloped viruses only. A similar model for enveloped viruses is complicated by a lack of data on enveloped virus pI, as well as uncertainties regarding the influence of the phospholipid envelope on charge and ion gradients.
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Affiliation(s)
- Joe Heffron
- Department of Civil, Construction and Environmental Engineering, Marquette University, Milwaukee, Wisconsin, USA
| | - Brooke K Mayer
- Department of Civil, Construction and Environmental Engineering, Marquette University, Milwaukee, Wisconsin, USA
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18
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Bajic G, Harrison SC. Antibodies That Engage the Hemagglutinin Receptor-Binding Site of Influenza B Viruses. ACS Infect Dis 2021; 7:1-5. [PMID: 33274930 DOI: 10.1021/acsinfecdis.0c00726] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We describe cross-reactive human antibodies recognizing influenza B viruses spanning nearly 80 years of antigenic drift. Structures show that they engage the receptor-binding site (RBS) of the viral hemagglutinin with strong similarities to their influenza A counterparts, despite structural differences between the RBS of influenza A and B. Our data show that these antibodies readily cross-react with both influenza B Victoria and Yamagata lineages. We also note that all antibodies are encoded by IGHV3-9/IGK1-33. Future research will provide insight into the prevalence of these antibodies in the human population.
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Affiliation(s)
- Goran Bajic
- Laboratory of Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Stephen C. Harrison
- Laboratory of Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
- Howard Hughes Medical Institute, Boston, Massachusetts 02115, United States
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19
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de Vries E, Du W, Guo H, de Haan CA. Influenza A Virus Hemagglutinin-Neuraminidase-Receptor Balance: Preserving Virus Motility. Trends Microbiol 2020; 28:57-67. [PMID: 31629602 PMCID: PMC7172302 DOI: 10.1016/j.tim.2019.08.010] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/29/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022]
Abstract
Influenza A viruses (IAVs) occasionally cross the species barrier and adapt to novel host species. This requires readjustment of the functional balance of the sialic acid receptor-binding hemagglutinin (HA) and the receptor-destroying neuraminidase (NA) to the sialoglycan-receptor repertoire of the new host. Novel techniques have revealed mechanistic details of this HA-NA-receptor balance, emphasizing a previously underappreciated crucial role for NA in driving the motility of receptor-associated IAV particles. Motility enables virion penetration of the sialylated mucus layer as well as attachment to, and uptake into, underlying epithelial cells. As IAVs are essentially irreversibly bound in the absence of NA activity, the fine-tuning of the HA-NA-receptor balance rather than the binding avidity of IAV particles per se is an important factor in determining host species tropism.
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Affiliation(s)
- Erik de Vries
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands.
| | - Wenjuan Du
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
| | - Hongbo Guo
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
| | - Cornelis A.M. de Haan
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands,Correspondence:
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20
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Dawson WK, Lazniewski M, Plewczynski D. RNA structure interactions and ribonucleoprotein processes of the influenza A virus. Brief Funct Genomics 2019; 17:402-414. [PMID: 29040388 PMCID: PMC6252904 DOI: 10.1093/bfgp/elx028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In one more years, we will ‘celebrate’ an exact centenary of the Spanish flu pandemic. With the rapid evolution of the influenza virus, the possibility of novel pandemic remains ever a concern. This review covers our current knowledge of the influenza A virus: on the role of RNA in translation, replication, what is known of the expressed proteins and the protein products generated from alternative splicing, and on the role of base pairing in RNA structure. We highlight the main events associated with viral entry into the cell, the transcription and replication process, an export of the viral genetic material from the nucleus and the final release of the virus. We discuss the observed potential roles of RNA secondary structure (the RNA base-pairing arrangement) and RNA/RNA interactions in this scheme.
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Affiliation(s)
- Wayne K Dawson
- Bio-information Lab, University of Tokyo.,University of Warsaw, Center of New Technologies (CeNT), Warsaw, Poland
| | - Michal Lazniewski
- University of Warsaw, Center of New Technologies (CeNT), Warsaw, Poland
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21
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Du R, Cui Q, Rong L. Competitive Cooperation of Hemagglutinin and Neuraminidase during Influenza A Virus Entry. Viruses 2019; 11:v11050458. [PMID: 31137516 PMCID: PMC6563287 DOI: 10.3390/v11050458] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/17/2019] [Accepted: 05/18/2019] [Indexed: 12/15/2022] Open
Abstract
The hemagglutinin (HA) and neuraminidase (NA) of influenza A virus possess antagonistic activities on interaction with sialic acid (SA), which is the receptor for virus attachment. HA binds SA through its receptor-binding sites, while NA is a receptor-destroying enzyme by removing SAs. The function of HA during virus entry has been extensively investigated, however, examination of NA has long been focused to its role in the exit of progeny virus from infected cells, and the role of NA in the entry process is still under-appreciated. This review summarizes the current understanding of the roles of HA and NA in relation to each other during virus entry.
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Affiliation(s)
- Ruikun Du
- College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, China.
- Shandong Provincial Collaborative Innovation Center for Antiviral Traditional Chinese Medicine, Jinan 250355, China.
- Qingdao Academy of Chinese Medicinal Sciences, Shandong University of Traditional Chinese Medicine, Qingdao 266122, China.
| | - Qinghua Cui
- College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, China.
- Shandong Provincial Collaborative Innovation Center for Antiviral Traditional Chinese Medicine, Jinan 250355, China.
- Qingdao Academy of Chinese Medicinal Sciences, Shandong University of Traditional Chinese Medicine, Qingdao 266122, China.
| | - Lijun Rong
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
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22
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Di Iorio D, Verheijden ML, van der Vries E, Jonkheijm P, Huskens J. Weak Multivalent Binding of Influenza Hemagglutinin Nanoparticles at a Sialoglycan-Functionalized Supported Lipid Bilayer. ACS NANO 2019; 13:3413-3423. [PMID: 30844236 PMCID: PMC6439437 DOI: 10.1021/acsnano.8b09410] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/07/2019] [Indexed: 05/28/2023]
Abstract
Quantification of the multivalent interactions of influenza viruses binding at interfaces may provide ways to tackle key biological questions regarding influenza virulence and zoonoses. Yet, the deconvolution of the contributions of molecular and interfacial parameters, such as valency, interaction area, and receptor density, to the binding of whole viruses is hindered by difficulties in the direct determination of these parameters. We report here a chemical platform technology to study the binding of multivalent recombinant hemagglutinin (rHA) nanoparticles at artificial sialoglycan cell receptor-presenting interfaces in which all these parameters can be derived, thus allowing the desired full and quantitative binding analysis. SiO2 substrates were functionalized with supported lipid bilayers containing a targeted and tunable fraction of a biotinylated lipid, followed by the adsorption of streptavidin and biotinylated polyvalent 2,3- or 2,6-sialyl lactosamine (SLN). rHA nanoparticles were used as a virus mimic to provide a good prediction of the number of interactions involved in binding. Low nanomolar affinities and selectivities for binding at the 2,6-SLN platforms were observed for rHA particles from three different virus variants. When fitting the data to a multivalency model, the nanomolar overall affinity appears to be achieved by 6-9 HA-sugar molecular interaction pairs, which individually present a rapid association/dissociation behavior. This dynamic behavior may be an essential biological attribute in the functioning of the influenza virus.
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Affiliation(s)
- 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
| | - Mark L. Verheijden
- Molecular
Nanofabrication Group, MESA + Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Erhard van der Vries
- Virology
Division, Department of Infectious Diseases and Immunology, Faculty
of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
| | - Pascal Jonkheijm
- Molecular
Nanofabrication Group, MESA + Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - 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
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23
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Reiter-Scherer V, Cuellar-Camacho JL, Bhatia S, Haag R, Herrmann A, Lauster D, Rabe JP. Force Spectroscopy Shows Dynamic Binding of Influenza Hemagglutinin and Neuraminidase to Sialic Acid. Biophys J 2019; 116:1037-1048. [PMID: 30799074 DOI: 10.1016/j.bpj.2019.01.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/30/2018] [Accepted: 01/14/2019] [Indexed: 10/27/2022] Open
Abstract
The influenza A virus infects target cells through multivalent interactions of its major spike proteins, hemagglutinin (HA) and neuraminidase (NA), with the cellular receptor sialic acid (SA). HA is known to mediate the attachment of the virion to the cell, whereas NA enables the release of newly formed virions by cleaving SA from the cell. Because both proteins target the same receptor but have antagonistic functions, virus infection depends on a properly tuned balance of the kinetics of HA and NA activities for viral entry to and release from the host cell. Here, dynamic single-molecule force spectroscopy, based on scanning force microscopy, was employed to determine these bond-specific kinetics, characterized by the off rate koff, rupture length xβ and on rate kon, as well as the related free-energy barrier ΔG and the dissociation constant KD. Measurements were conducted using surface-immobilized HA and NA of the influenza A virus strain A/California/04/2009 and a novel, to our knowledge, synthetic SA-displaying receptor for functionalization of the force probe. Single-molecule force spectroscopy at force loading rates between 100 and 50,000 pN/s revealed most probable rupture forces of the protein-SA bond in the range of 10-100 pN. Using an extension of the widely applied Bell-Evans formalism by Friddle, De Yoreo, and co-workers, it is shown that HA features a smaller xβ, a larger koff and a smaller ΔG than NA. Measurements of the binding probability at increasing contact time between the scanning force microscopy force probe and the surface allow an estimation of KD, which is found to be three times as large for HA than for NA. This suggests a stronger interaction for NA-SA than for HA-SA. The biological implications in regard to virus binding to the host cell and the release of new virions from the host cell are discussed.
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Affiliation(s)
| | | | - Sumati Bhatia
- Department of Chemistry, Freie Universität Berlin, Berlin, Germany
| | - Rainer Haag
- Department of Chemistry, Freie Universität Berlin, Berlin, Germany
| | - Andreas Herrmann
- Department of Biology and IRI Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Daniel Lauster
- Department of Biology and IRI Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.
| | - Jürgen P Rabe
- Department of Physics and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, Germany.
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24
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Kosik I, Angeletti D, Gibbs JS, Angel M, Takeda K, Kosikova M, Nair V, Hickman HD, Xie H, Brooke CB, Yewdell JW. Neuraminidase inhibition contributes to influenza A virus neutralization by anti-hemagglutinin stem antibodies. J Exp Med 2019; 216:304-316. [PMID: 30683737 PMCID: PMC6363425 DOI: 10.1084/jem.20181624] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/03/2018] [Accepted: 01/03/2019] [Indexed: 11/18/2022] Open
Abstract
Broadly neutralizing antibodies (Abs) that bind the influenza virus hemagglutinin (HA) stem may enable universal influenza vaccination. Here, we show that anti-stem Abs sterically inhibit viral neuraminidase (NA) activity against large substrates, with activity inversely proportional to the length of the fibrous NA stalk that supports the enzymatic domain. By modulating NA stalk length in recombinant IAVs, we show that anti-stem Abs inhibit virus release from infected cells by blocking NA, accounting for their in vitro neutralization activity. NA inhibition contributes to anti-stem Ab protection in influenza-infected mice, likely due at least in part to NA-mediated inhibition of FcγR-dependent activation of innate immune cells by Ab bound to virions. Food and Drug Administration-approved NA inhibitors enhance anti-stem-based Fc-dependent immune cell activation, raising the possibility of therapeutic synergy between NA inhibitors and anti-stem mAb treatment in humans.
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Affiliation(s)
- Ivan Kosik
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD
| | - Davide Angeletti
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD
| | - James S Gibbs
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD
| | - Matthew Angel
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD
| | - Kazuyo Takeda
- Microscopy and Imaging Core Facility, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD
| | - Martina Kosikova
- Laboratory of Respiratory Viral Diseases, Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD
| | - Vinod Nair
- Electron Microscopy Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT
| | - Heather D Hickman
- Viral Immunity and Pathogenesis Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD
| | - Hang Xie
- Laboratory of Respiratory Viral Diseases, Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD
| | | | - Jonathan W Yewdell
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD
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25
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McAuley JL, Gilbertson BP, Trifkovic S, Brown LE, McKimm-Breschkin JL. Influenza Virus Neuraminidase Structure and Functions. Front Microbiol 2019; 10:39. [PMID: 30761095 PMCID: PMC6362415 DOI: 10.3389/fmicb.2019.00039] [Citation(s) in RCA: 236] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/10/2019] [Indexed: 12/31/2022] Open
Abstract
With the constant threat of emergence of a novel influenza virus pandemic, there must be continued evaluation of the molecular mechanisms that contribute to virulence. Although the influenza A virus surface glycoprotein neuraminidase (NA) has been studied mainly in the context of its role in viral release from cells, accumulating evidence suggests it plays an important, multifunctional role in virus infection and fitness. This review investigates the various structural features of NA, linking these with functional outcomes in viral replication. The contribution of evolving NA activity to viral attachment, entry and release of virions from infected cells, and maintenance of functional balance with the viral hemagglutinin are also discussed. Greater insight into the role of this important antiviral drug target is warranted.
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Affiliation(s)
- Julie L McAuley
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Brad P Gilbertson
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Sanja Trifkovic
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.,Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, United States
| | - Lorena E Brown
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Jennifer L McKimm-Breschkin
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
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26
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Amorim MJ. A Comprehensive Review on the Interaction Between the Host GTPase Rab11 and Influenza A Virus. Front Cell Dev Biol 2019; 6:176. [PMID: 30687703 PMCID: PMC6333742 DOI: 10.3389/fcell.2018.00176] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/17/2018] [Indexed: 12/20/2022] Open
Abstract
This year marks the 100th anniversary of one of the deadliest pandemic outbreaks, commonly referred as the Spanish Flu, that was caused by influenza A virus (IAV). Since then, IAV has been in governmental agendas worldwide, and a lot of effort has been put into understanding the pathogen's lifecycle, predict and mitigate the emergence of the strains that provoke yearly epidemics and pandemic events. Despite decades of research and seminal contributions there is still a lot to be investigated. In particular for this review, IAV lifecycle that takes place inside the host cell is not fully understood. Two steps that need clarification include genome transport to budding sites and genome assembly, the latter a complex process challenged by the nature of IAV genome that is divided into eight distinct parts. Assembly of such segmented genome is crucial to form fully infectious viral particles but is also critical for the emergence of viruses with pandemic potential that arise when avian and human IAV strains co-infect a host. The host GTPase Rab11 was separately implicated in both steps, and, interestingly these processes are beginning to emerge as being intimately related. Rab11 was initially proposed to be involved in the budding/release of IAV virions. It was subsequently shown to transport progeny genome, and later proposed to promote assembly of viral genome, but the underlying bridging mechanism the two is far from clear. For simplicity, this Rab11-centric review provides an initial separate account of Rab11 involvement in genome transport and in assembly. IAV genome assembly is a complicated molecular biology process, and therefore earned a dedicated section on how/if the viral genome forms a genomic supramolecular complex. Both topics present intricate challenges, outstanding questions, and unique controversies. At the end of the review, I will explore possible mechanisms intertwining IAV vRNP transport and genome assembly. Importantly, Rab11 has recently emerged as a key factor subverted by evolutionary unrelated viral families (Paramyxo, Bunya, and Orthomyxoviruses, among many others) and bacteria (Salmonella and Shigella) relevant to human health. This review provides a framework to identify common biological principles among the lifecycles of these pathogens.
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Affiliation(s)
- Maria João Amorim
- Cell Biology of Viral Infection Lab, Instituto Gulbenkian de Ciência, Oeiras, Portugal
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Vahey MD, Fletcher DA. Low-Fidelity Assembly of Influenza A Virus Promotes Escape from Host Cells. Cell 2018; 176:281-294.e19. [PMID: 30503209 DOI: 10.1016/j.cell.2018.10.056] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 09/05/2018] [Accepted: 10/26/2018] [Indexed: 12/11/2022]
Abstract
Influenza viruses inhabit a wide range of host environments using a limited repertoire of protein components. Unlike viruses with stereotyped shapes, influenza produces virions with significant morphological variability even within clonal populations. Whether this tendency to form pleiomorphic virions is coupled to compositional heterogeneity and whether it affects replicative fitness remains unclear. Here, we address these questions by developing a strain of influenza A virus amenable to rapid compositional characterization through quantitative, site-specific labeling of viral proteins. Using this strain, we find that influenza A produces virions with broad variations in size and composition from even single infected cells. This phenotypic variability contributes to virus survival during environmental challenges, including exposure to antivirals. Complementing genetic adaptations that act over larger populations and longer times, this "low-fidelity" assembly of influenza A virus allows small populations to survive environments that fluctuate over individual replication cycles.
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Affiliation(s)
- Michael D Vahey
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Daniel A Fletcher
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA; University of California, Berkeley/University of California, San Francisco Graduate Group in Bioengineering, Berkeley, CA 94720, USA; Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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28
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Amaro RE, Ieong PU, Huber G, Dommer A, Steven AC, Bush RM, Durrant JD, Votapka LW. A Computational Assay that Explores the Hemagglutinin/Neuraminidase Functional Balance Reveals the Neuraminidase Secondary Site as a Novel Anti-Influenza Target. ACS CENTRAL SCIENCE 2018; 4:1570-1577. [PMID: 30555910 PMCID: PMC6276040 DOI: 10.1021/acscentsci.8b00666] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Indexed: 05/09/2023]
Abstract
Studies of pathogen-host specificity, virulence, and transmissibility are critical for basic research as well as for assessing the pandemic potential of emerging infectious diseases. This is especially true for viruses such as influenza, which continue to affect millions of people annually through both seasonal and occasional pandemic events. Although the influenza virus has been fairly well studied for decades, our understanding of host-cell binding and its relation to viral transmissibility and infection is still incomplete. Assessing the binding mechanisms of complex biological systems with atomic-scale detail is challenging given current experimental limitations. Much remains to be learned, for example, about how the terminal residue of influenza-binding host-cell receptors (sialic acid) interacts with the viral surface. Here, we present an integrative structural-modeling and physics-based computational assay that reveals the sialic acid association rate constants (k on) to three influenza sites: the hemagglutinin (HA), neuraminidase (NA) active, and NA secondary binding sites. We developed a series of highly detailed (atomic-resolution) structural models of fully intact influenza viral envelopes. Brownian dynamics simulations of these systems showed how structural properties, such as stalk height and secondary-site binding, affect sialic acid k on values. Comparing the k on values of the three sialic acid binding sites across different viral strains suggests a detailed model of encounter-complex formation and indicates that the secondary NA binding site may play a compensatory role in host-cell receptor binding. Our method elucidates the competition among these sites, all present on the same virion, and provides a new technology for directly studying the functional balance between HA and NA.
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Affiliation(s)
- Rommie E. Amaro
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California, United States
- E-mail: . (R.E.A.)
| | - Pek U Ieong
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California, United States
| | - Gary Huber
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California, United States
| | - Abigail Dommer
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California, United States
| | - Alasdair C. Steven
- Structural
Biology Laboratory, National Institutes
of Health, Bethesda, Maryland, United States
| | - Robin M. Bush
- Department
of Ecology and Evolutionary Biology, University
of California, Irvine, Irvine, California, United States
| | - Jacob D. Durrant
- Department
of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- E-mail: . (J.D.D.)
| | - Lane W. Votapka
- Department
of Chemistry, Point Loma Nazarene University, San Diego, California, United States
- E-mail: . (L.W.V.)
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Huggins DJ, Biggin PC, Dämgen MA, Essex JW, Harris SA, Henchman RH, Khalid S, Kuzmanic A, Laughton CA, Michel J, Mulholland AJ, Rosta E, Sansom MSP, van der Kamp MW. Biomolecular simulations: From dynamics and mechanisms to computational assays of biological activity. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1393] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- David J. Huggins
- TCM Group, Cavendish Laboratory University of Cambridge Cambridge UK
- Unilever Centre, Department of Chemistry University of Cambridge Cambridge UK
- Department of Physiology and Biophysics Weill Cornell Medical College New York NY
| | | | - Marc A. Dämgen
- Department of Biochemistry University of Oxford Oxford UK
| | - Jonathan W. Essex
- School of Chemistry University of Southampton Southampton UK
- Institute for Life Sciences University of Southampton Southampton UK
| | - Sarah A. Harris
- School of Physics and Astronomy University of Leeds Leeds UK
- Astbury Centre for Structural and Molecular Biology University of Leeds Leeds UK
| | - Richard H. Henchman
- Manchester Institute of Biotechnology The University of Manchester Manchester UK
- School of Chemistry The University of Manchester Oxford UK
| | - Syma Khalid
- School of Chemistry University of Southampton Southampton UK
- Institute for Life Sciences University of Southampton Southampton UK
| | | | - Charles A. Laughton
- School of Pharmacy University of Nottingham Nottingham UK
- Centre for Biomolecular Sciences University of Nottingham Nottingham UK
| | - Julien Michel
- EaStCHEM school of Chemistry University of Edinburgh Edinburgh UK
| | - Adrian J. Mulholland
- Centre of Computational Chemistry, School of Chemistry University of Bristol Bristol UK
| | - Edina Rosta
- Department of Chemistry King's College London London UK
| | | | - Marc W. van der Kamp
- Centre of Computational Chemistry, School of Chemistry University of Bristol Bristol UK
- School of Biochemistry, Biomedical Sciences Building University of Bristol Bristol UK
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Guo H, Rabouw H, Slomp A, Dai M, van der Vegt F, van Lent JWM, McBride R, Paulson JC, de Groot RJ, van Kuppeveld FJM, de Vries E, de Haan CAM. Kinetic analysis of the influenza A virus HA/NA balance reveals contribution of NA to virus-receptor binding and NA-dependent rolling on receptor-containing surfaces. PLoS Pathog 2018; 14:e1007233. [PMID: 30102740 PMCID: PMC6107293 DOI: 10.1371/journal.ppat.1007233] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/23/2018] [Accepted: 07/19/2018] [Indexed: 01/02/2023] Open
Abstract
Interactions of influenza A virus (IAV) with sialic acid (SIA) receptors determine viral fitness and host tropism. Binding to mucus decoy receptors and receptors on epithelial host cells is determined by a receptor-binding hemagglutinin (HA), a receptor-destroying neuraminidase (NA) and a complex in vivo receptor-repertoire. The crucial but poorly understood dynamics of these multivalent virus-receptor interactions cannot be properly analyzed using equilibrium binding models and endpoint binding assays. In this study, the use of biolayer interferometric analysis revealed the virtually irreversible nature of IAV binding to surfaces coated with synthetic sialosides or engineered sialoglycoproteins in the absence of NA activity. In addition to HA, NA was shown to be able to contribute to the initial binding rate while catalytically active. Virus-receptor binding in turn contributed to receptor cleavage by NA. Multiple low-affinity HA-SIA interactions resulted in overall extremely high avidity but also permitted a dynamic binding mode, in which NA activity was driving rolling of virus particles over the receptor-surface. Virus dissociation only took place after receptor density of the complete receptor-surface was sufficiently decreased due to NA activity of rolling IAV particles. The results indicate that in vivo IAV particles, after landing on the mucus layer, reside continuously in a receptor-bound state while rolling through the mucus layer and over epithelial cell surfaces driven by the HA-NA-receptor balance. Quantitative BLI analysis enabled functional examination of this balance which governs this dynamic and motile interaction that is expected to be crucial for penetration of the mucus layer and subsequent infection of cells by IAV but likely also by other enveloped viruses carrying a receptor-destroying enzyme in addition to a receptor-binding protein. Influenza A virus (IAV) tropism is largely determined by the interaction of virus particles with the sialic acid receptor repertoire of the host. IAVs encounter a diverse range of sialic acid receptors that can function as decoys (e.g. in the mucus that covers epithelial cells) or as entry receptors. We studied the dynamics of IAV-receptor interactions in real-time using biolayer interferometry (BLI) in combination with synthetic glycans and recombinant sialoglycoproteins mimicking in vivo receptors. Thereby we could show that IAVs do not continuously associate and dissociate with receptor-coated surfaces but actually were rolling over the surface with which they remained permanently associated until the receptors were sufficiently cleared. This required the concerted action of the receptor-binding hemagglutinin (HA) and the receptor-destroying neuraminidase (NA) on the receptor surface. We could quantify the precise HA-NA-receptor balance that determined the speed of rolling and eventual elution from the surface by BLI and propose a model in which IAV is permanently, but dynamically, associated with receptors on mucus or host cells in vivo.
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Affiliation(s)
- Hongbo Guo
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Huib Rabouw
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Anne Slomp
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Meiling Dai
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Floor van der Vegt
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Jan W. M. van Lent
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, PB Wageningen, the Netherlands
| | - Ryan McBride
- Departments of Cell and Molecular Biology, Chemical Physiology, and Immunology and Microbial Science, Scripps Research Institute, La Jolla, California, United States of America
| | - James C. Paulson
- Departments of Cell and Molecular Biology, Chemical Physiology, and Immunology and Microbial Science, Scripps Research Institute, La Jolla, California, United States of America
| | - Raoul J. de Groot
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Frank J. M. van Kuppeveld
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Erik de Vries
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
- * E-mail: (EDV); (CAMDH)
| | - Cornelis A. M. de Haan
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
- * E-mail: (EDV); (CAMDH)
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31
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Morphological characterization of a plant-made virus-like particle vaccine bearing influenza virus hemagglutinins by electron microscopy. Vaccine 2018; 36:2147-2154. [PMID: 29550194 DOI: 10.1016/j.vaccine.2018.02.106] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/19/2018] [Accepted: 02/23/2018] [Indexed: 12/17/2022]
Abstract
Plant-made virus-like particle (VLP) vaccines that display wild-type influenza hemagglutinin (HA) are rapidly advancing through clinical trials. Produced by transient transfection of Nicotiana benthamiana, these novel vaccines are unusually immunogenic, eliciting both humoral and cellular responses. Here, we directly visualized VLPs bearing either HA trimers derived from strains A/California/7/2009 or A/Indonesia/5/05 using cryo-electron microscopy and determined the 3D organization of the VLPs using cryo-electron tomography. More than 99.9% of the HA trimers in the vaccine preparations were found on discoid and ovoid-shaped particles. The discoid-shaped VLPs presented HA trimers on their outer diameter. The ovoid-shaped VLPs contained HA trimers evenly distributed at their surface. The VLPs were stable for 12 months at 4 °C. Early interactions of the VLPs with mouse dendritic and human monocytoid (U-937) cells were visualized by electron microscopy after resin-embedding and sectioning. The VLP particles were observed bound to plasma membranes as well as inside vesicles. Mouse dendritic cells exposed to VLPs displayed classic morphological changes associated with activation including the extensive formation of dendrites. Our findings demonstrate that plant-made VLPs bearing influenza HA trimers are morphologically stable over time and raise the possibility that these VLPs may interact with and activate antigen-presenting cells in a manner similar to the intact virus.
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Dissection of Epitope-Specific Mechanisms of Neutralization of Influenza Virus by Intact IgG and Fab Fragments. J Virol 2018; 92:JVI.02006-17. [PMID: 29263254 DOI: 10.1128/jvi.02006-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 12/08/2017] [Indexed: 11/20/2022] Open
Abstract
The neutralizing antibody (nAb) response against the influenza virus hemagglutinin (HA) fusion glycoprotein is important for preventing viral infection, but we lack a comprehensive understanding of the mechanisms by which these antibodies act. Here we investigated the effect of nAb binding and the role of IgG bivalency in the inhibition of HA function for nAbs targeting distinct HA epitopes. HC19 targets the receptor binding pocket at the distal end of HA, while FI6v3 binds primarily to the HA2 fusion subunit toward the base of the stalk. Surprisingly, HC19 inhibited the ability of HA to induce lipid mixing by preventing the structural rearrangement of HA under fusion-activating conditions. These results suggest that nAbs such as HC19 not only act by blocking receptor binding but also inhibit key late-stage HA conformational changes required for fusion. Intact HC19 IgG was also shown to cross-link separate virus particles, burying large proportions of HA within aggregates where they are blocked from interacting with target membranes; Fabs yielded no such aggregation and displayed weaker neutralization than IgG, emphasizing the impact of bivalency on the ability to neutralize virus. In contrast, the stem-targeting nAb FI6v3 did not aggregate particles. The Fab fragment was significantly less effective than IgG in preventing both membrane disruption and fusion. We infer that interspike cross-linking within a given particle by FI6v3 IgG may be critical to its potent neutralization, as no significant neutralization occurred with Fabs. These results demonstrate that IgG bivalency enhances HA inhibition through functionally important modes not evident in pared-down Fab-soluble HA structures.IMPORTANCE The influenza virus hemagglutinin (HA) fusion glycoprotein mediates entry into target cells and is the primary antigenic target of neutralizing antibodies (nAbs). Our current structural understanding of mechanisms of antibody (Ab)-mediated neutralization largely relies on the high-resolution characterization of antigen binding (Fab) fragments in complex with soluble, isolated antigen constructs by cryo-electron microscopy (EM) single-particle reconstruction or X-ray crystallography. Interactions between full-length IgG and whole virions have not been well characterized, and a gap remains in our understanding of how intact Abs neutralize virus and prevent infection. Using structural and biophysical approaches, we observed that Ab-mediated inhibition of HA function and neutralization of virus infectivity occur by multiple coexisting mechanisms, are largely dependent on the specific epitope that is targeted, and are highly dependent on the bivalent nature of IgG molecules.
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Shepardson KM, Schwarz B, Larson K, Morton RV, Avera J, McCoy K, Caffrey A, Harmsen A, Douglas T, Rynda-Apple A. Induction of Antiviral Immune Response through Recognition of the Repeating Subunit Pattern of Viral Capsids Is Toll-Like Receptor 2 Dependent. mBio 2017; 8:e01356-17. [PMID: 29138299 PMCID: PMC5686532 DOI: 10.1128/mbio.01356-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/10/2017] [Indexed: 12/25/2022] Open
Abstract
Although viruses and viral capsids induce rapid immune responses, little is known about viral pathogen-associated molecular patterns (PAMPs) that are exhibited on their surface. Here, we demonstrate that the repeating protein subunit pattern common to most virus capsids is a molecular pattern that induces a Toll-like-receptor-2 (TLR2)-dependent antiviral immune response. This early antiviral immune response regulates the clearance of subsequent bacterial superinfections, which are a primary cause of morbidities associated with influenza virus infections. Utilizing this altered susceptibility to subsequent bacterial challenge as an outcome, we determined that multiple unrelated, empty, and replication-deficient capsids initiated early TLR2-dependent immune responses, similar to intact influenza virus or murine pneumovirus. These TLR2-mediated responses driven by the capsid were not dependent upon the capsid's shape, size, origin, or amino acid sequence. However, they were dependent upon the multisubunit arrangement of the capsid proteins, because unlike intact capsids, individual capsid subunits did not enhance bacterial clearance. Further, we demonstrated that even a linear microfilament protein built from repeating protein subunits (F-actin), but not its monomer (G-actin), induced similar kinetics of subsequent bacterial clearance as did virus capsid. However, although capsids and F-actin induced similar bacterial clearance, in macrophages they required distinct TLR2 heterodimers for this response (TLR2/6 or TLR2/1, respectively) and different phagocyte populations were involved in the execution of these responses in vivo Our results demonstrate that TLR2 responds to invading viral particles that are composed of repeating protein subunits, indicating that this common architecture of virus capsids is a previously unrecognized molecular pattern.IMPORTANCE Rapid and precise pathogen identification is critical for the initiation of pathogen-specific immune responses and pathogen clearance. Bacteria and fungi express common molecular patterns on their exteriors that are recognized by cell surface-expressed host pattern recognition receptors (PRRs) prior to infection. In contrast, viral molecular patterns are primarily nucleic acids, which are recognized after virus internalization. We found that an initial antiviral immune response is induced by the repeating subunit pattern of virus exteriors (capsids), and thus, induction of this response is independent of viral infection. This early response to viral capsids required the cell surface-expressed PRR TLR2 and allowed for improved clearance of subsequent bacterial infection that commonly complicates respiratory viral infections. Since the repeating protein subunit pattern is conserved across viral capsids, this suggests that it is not easy for a virus to change without altering fitness. Targeting this vulnerability could lead to development of a universal antiviral vaccine.
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Affiliation(s)
- Kelly M Shepardson
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Benjamin Schwarz
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Kyle Larson
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Rachelle V Morton
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - John Avera
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Kimberly McCoy
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Alayna Caffrey
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Ann Harmsen
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Trevor Douglas
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Agnieszka Rynda-Apple
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
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Wasik BR, Barnard KN, Ossiboff RJ, Khedri Z, Feng KH, Yu H, Chen X, Perez DR, Varki A, Parrish CR. Distribution of O-Acetylated Sialic Acids among Target Host Tissues for Influenza Virus. mSphere 2017; 2:e00379-16. [PMID: 28904995 PMCID: PMC5588038 DOI: 10.1128/msphere.00379-16] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 08/17/2017] [Indexed: 12/30/2022] Open
Abstract
Sialic acids (Sias) are important glycans displayed on the cells and tissues of many different animals and are frequent targets for binding and modification by pathogens, including influenza viruses. Influenza virus hemagglutinins bind Sias during the infection of their normal hosts, while the encoded neuraminidases and/or esterases remove or modify the Sia to allow virion release or to prevent rebinding. Sias naturally occur in a variety of modified forms, and modified Sias can alter influenza virus host tropisms through their altered interactions with the viral glycoproteins. However, the distribution of modified Sia forms and their effects on pathogen-host interactions are still poorly understood. Here we used probes developed from viral Sia-binding proteins to detect O-acetylated (4-O-acetyl, 9-O-acetyl, and 7,9-O-acetyl) Sias displayed on the tissues of some natural or experimental hosts for influenza viruses. These modified Sias showed highly variable displays between the hosts and tissues examined. The 9-O-acetyl (and 7,9-) modified Sia forms were found on cells and tissues of many hosts, including mice, humans, ferrets, guinea pigs, pigs, horses, dogs, as well as in those of ducks and embryonated chicken egg tissues and membranes, although in variable amounts. The 4-O-acetyl Sias were found in the respiratory tissues of fewer animals, being primarily displayed in the horse and guinea pig, but were not detected in humans or pigs. The results suggest that these Sia variants may influence virus tropisms by altering and selecting their cell interactions. IMPORTANCE Sialic acids (Sias) are key glycans that control or modulate many normal cell and tissue functions while also interacting with a variety of pathogens, including many different viruses. Sias are naturally displayed in a variety of different forms, with modifications at several positions that can alter their functional interactions with pathogens. In addition, Sias are often modified or removed by enzymes such as host or pathogen esterases or sialidases (neuraminidases), and Sia modifications can alter those enzymatic activities to impact pathogen infections. Sia chemical diversity in different hosts and tissues likely alters the pathogen-host interactions and influences the outcome of infection. Here we explored the display of 4-O-acetyl, 9-O-acetyl, and 7,9-O-acetyl modified Sia forms in some target tissues for influenza virus infection in mice, humans, birds, guinea pigs, ferrets, swine, horses, and dogs, which encompass many natural and laboratory hosts of those viruses.
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Affiliation(s)
- Brian R. Wasik
- Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Karen N. Barnard
- Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Robert J. Ossiboff
- Department of Population Medicine and Diagnostic Sciences, Animal Health Diagnostic Center, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Zahra Khedri
- Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California, USA
| | - Kurtis H. Feng
- Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Hai Yu
- Department of Chemistry, University of California, Davis, Davis, California, USA
| | - Xi Chen
- Department of Chemistry, University of California, Davis, Davis, California, USA
| | - Daniel R. Perez
- Department of Population Health, Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Ajit Varki
- Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California, USA
| | - Colin R. Parrish
- Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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35
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Das A, Gurale BP, Dhawane AN, Iyer SS. Synthesis of biotinylated bivalent zanamivir analogs as probes for influenza viruses. HETEROCYCL COMMUN 2017. [DOI: 10.1515/hc-2017-0088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractThe synthesis of a biotinylated bivalent zanamivir analog as a probe for influenza viruses is reported. The compound was used in a ‘glycan’ based sandwich assay; where glycans were immobilized on glass slides to capture strains of influenza A H1N1, A/Brisbane/59/2007 virus; the biotinylated bivalent zanamivir analog-labeled streptavidin complex was used as reporter. This research strongly suggests that glycans can be used for capturing and reporting influenza viruses and the biotinylated compounds can be used as probes for capturing and isolating influenza viruses from complex mixtures.
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Affiliation(s)
- Amrita Das
- Department of Chemistry, 788 Petit Science Center, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302, USA
| | - Bharat P. Gurale
- Department of Chemistry, 788 Petit Science Center, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302, USA
| | - Abasaheb N. Dhawane
- Department of Chemistry, 788 Petit Science Center, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302, USA
| | - Suri S. Iyer
- Department of Chemistry, 788 Petit Science Center, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302, USA
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36
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Wu NC, Wilson IA. A Perspective on the Structural and Functional Constraints for Immune Evasion: Insights from Influenza Virus. J Mol Biol 2017. [PMID: 28648617 DOI: 10.1016/j.jmb.2017.06.015] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Influenza virus evolves rapidly to constantly escape from natural immunity. Most humoral immune responses to influenza virus target the hemagglutinin (HA) glycoprotein, which is the major antigen on the surface of the virus. The HA is composed of a globular head domain for receptor binding and a stem domain for membrane fusion. The major antigenic sites of HA are located in the globular head subdomain, which is highly tolerant of amino acid substitutions and continual addition of glycosylation sites. Nonetheless, the evolution of the receptor-binding site and the stem region on HA is severely constrained by their functional roles in engaging the host receptor and in mediating membrane fusion, respectively. Here, we review how broadly neutralizing antibodies (bnAbs) exploit these evolutionary constraints to protect against diverse influenza strains. We also discuss the emerging role of other epitopes that are conserved only in subsets of viruses. This rapidly increasing knowledge of the evolutionary biology, immunology, structural biology, and virology of influenza virus is invaluable for development and design of more universal influenza vaccines and novel therapeutics.
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Affiliation(s)
- Nicholas C Wu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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37
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Kordyukova L. Structural and functional specificity of Influenza virus haemagglutinin and paramyxovirus fusion protein anchoring peptides. Virus Res 2017; 227:183-199. [DOI: 10.1016/j.virusres.2016.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 02/08/2023]
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38
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Domanska MK, Dunning RA, Dryden KA, Zawada KE, Yeager M, Kasson PM. Hemagglutinin Spatial Distribution Shifts in Response to Cholesterol in the Influenza Viral Envelope. Biophys J 2016; 109:1917-24. [PMID: 26536268 DOI: 10.1016/j.bpj.2015.09.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/29/2015] [Accepted: 09/18/2015] [Indexed: 12/18/2022] Open
Abstract
Influenza virus delivers its genome to the host cytoplasm via a process of membrane fusion mediated by the viral hemagglutinin protein. Optimal fusion likely requires multiple hemagglutinin trimers, so the spatial distribution of hemagglutinin on the viral envelope may influence fusion mechanism. We have previously shown that moderate depletion of cholesterol from the influenza viral envelope accelerates fusion kinetics even though it decreases fusion efficiency, both in a reversible manner. Here, we use electron cryo-microscopy to measure how the hemagglutinin lateral density in the viral envelope changes with cholesterol extraction. We extract this information by measuring the radial distribution function of electron density in >4000 viral images per sample, assigning hemagglutinin density by comparing images with and without anti-HA Fab bound. On average, hemagglutinin trimers move closer together: we estimate that the typical trimer-trimer spacing reduces from 94 to 84 Å when ∼90% of cholesterol is removed from the viral membrane. Upon restoration of viral envelope cholesterol, this spacing once again expands. This finding can qualitatively explain the observed changes to fusion kinetics: contemporary models from single-virus microscopy are that fusion requires the engagement of several hemagglutinin trimers in close proximity. If removing cholesterol increases the lateral density of hemagglutinin, this should result in an increase in the rate of fusion.
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Affiliation(s)
- Marta K Domanska
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Rebecca A Dunning
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Kelly A Dryden
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Katarzyna E Zawada
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Mark Yeager
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Peter M Kasson
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia.
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39
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Calder LJ, Rosenthal PB. Cryomicroscopy provides structural snapshots of influenza virus membrane fusion. Nat Struct Mol Biol 2016; 23:853-8. [PMID: 27501535 PMCID: PMC6485592 DOI: 10.1038/nsmb.3271] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/07/2016] [Indexed: 01/01/2023]
Abstract
The lipid-enveloped influenza virus enters host cells during infection by binding cell surface receptors and, following receptor-mediated endocytosis, fusing with the membrane of the endosome, delivering the viral genome and transcription machinery into the host cell. These events are mediated by the haemagglutinin (HA) surface glycoprotein. At the low pH of the endosome, an irreversible conformational change in the HA, including the exposure of the hydrophobic fusion peptide, activates membrane fusion. Here we use electron cryomicroscopy and cryotomography to image influenza virus fusion with target membranes at low pH. We visualize structural intermediates of HA and their interactions with membranes during the course of membrane fusion as well as ultra-structural changes in the virus that accompany membrane fusion. Our observations are relevant to a wide range of protein-mediated membrane fusion processes and demonstrate how dynamic membrane events may be studied by cryomicroscopy.
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40
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Reddy T, Sansom MSP. Computational virology: From the inside out. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1858:1610-8. [PMID: 26874202 PMCID: PMC4884666 DOI: 10.1016/j.bbamem.2016.02.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 12/23/2022]
Abstract
Viruses typically pack their genetic material within a protein capsid. Enveloped viruses also have an outer membrane made up of a lipid bilayer and membrane-spanning glycoproteins. X-ray diffraction and cryoelectron microscopy provide high resolution static views of viral structure. Molecular dynamics (MD) simulations may be used to provide dynamic insights into the structures of viruses and their components. There have been a number of simulations of viral capsids and (in some cases) of the inner core of RNA or DNA packaged within them. These simulations have generally focussed on the structural integrity and stability of the capsid and/or on the influence of the nucleic acid core on capsid stability. More recently there have been a number of simulation studies of enveloped viruses, including HIV-1, influenza A, and dengue virus. These have addressed the dynamic behaviour of the capsid, the matrix, and/or of the outer envelope. Analysis of the dynamics of the lipid bilayer components of the envelopes of influenza A and of dengue virus reveals a degree of biophysical robustness, which may contribute to the stability of virus particles in different environments. Significant computational challenges need to be addressed to aid simulation of complex viruses and their membranes, including the need to integrate structural data from a range of sources to enable us to move towards simulations of intact virions. This article is part of a Special Issue entitled: Membrane Proteins edited by J.C. Gumbart and Sergei Noskov.
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Affiliation(s)
- Tyler Reddy
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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41
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Dadonaite B, Vijayakrishnan S, Fodor E, Bhella D, Hutchinson EC. Filamentous influenza viruses. J Gen Virol 2016; 97:1755-1764. [PMID: 27365089 DOI: 10.1099/jgv.0.000535] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Clinical isolates of influenza virus produce pleomorphic virus particles, including extremely long filamentous virions. In contrast, strains of influenza that have adapted to laboratory growth typically produce only spherical virions. As a result, the filamentous phenotype has been overlooked in most influenza virus research. Recent advances in imaging and improved animal models have highlighted the distinct structure and functional relevance of filamentous virions. In this review we summarize what is currently known about these strikingly elongated virus particles and discuss their possible roles in clinical infections.
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Affiliation(s)
- Bernadeta Dadonaite
- Sir William Dunn School of Pathology, University of Oxford, South Parks Rd, Oxford OX1 3RE, UK
| | - Swetha Vijayakrishnan
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, 464 Bearsden Rd, Bearsden, Glasgow, Lanarkshire G61 1QH, UK
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, South Parks Rd, Oxford OX1 3RE, UK
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, 464 Bearsden Rd, Bearsden, Glasgow, Lanarkshire G61 1QH, UK
| | - Edward C Hutchinson
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, 464 Bearsden Rd, Bearsden, Glasgow, Lanarkshire G61 1QH, UK.,Sir William Dunn School of Pathology, University of Oxford, South Parks Rd, Oxford OX1 3RE, UK
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42
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Chlanda P, Zimmerberg J. Protein-lipid interactions critical to replication of the influenza A virus. FEBS Lett 2016; 590:1940-54. [PMID: 26921878 DOI: 10.1002/1873-3468.12118] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/08/2016] [Accepted: 02/21/2016] [Indexed: 12/12/2022]
Abstract
Influenza A virus (IAV) assembles on the plasma membrane where viral proteins localize to form a bud encompassing the viral genome, which ultimately pinches off to give rise to newly formed infectious virions. Upon entry, the virus faces the opposite task-fusion with the endosomal membrane and disassembly to deliver the viral genome to the cytoplasm. There are at least four influenza proteins-hemagglutinin (HA), neuraminidase (NA), matrix 1 protein (M1), and the M2 ion channel-that are known to directly interact with the cellular membrane and modify membrane curvature in order to both assemble and disassemble membrane-enveloped virions. Here, we summarize and discuss current knowledge of the interactions of lipids and membrane proteins involved in the IAV replication cycle.
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Affiliation(s)
- Petr Chlanda
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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43
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Reddy T, Sansom MSP. The Role of the Membrane in the Structure and Biophysical Robustness of the Dengue Virion Envelope. Structure 2016; 24:375-82. [PMID: 26833387 PMCID: PMC4780862 DOI: 10.1016/j.str.2015.12.011] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 12/15/2015] [Accepted: 12/22/2015] [Indexed: 01/11/2023]
Abstract
The dengue virion is surrounded by an envelope of membrane proteins surrounding a lipid bilayer. We have combined the cryoelectron microscopy structures of the membrane proteins (PDB: 3J27) with a lipid bilayer whose composition is based on lipidomics data for insect cell membranes, to obtain a near-atomic resolution computational model of the envelope of the dengue virion. A coarse-grained molecular dynamics simulation on the microsecond timescale enables analysis of key biophysical properties of the dengue outer envelope. Properties analyzed include area per lipid values (for a spherical virion with a mixed lipid composition), bilayer thickness, and lipid diffusion coefficients. Despite the absence of cholesterol from the lipid bilayer, the virion exhibits biophysical robustness (slow lipid diffusion alongside stable bilayer thickness, virion diameter, and shape) that matches the cholesterol-rich membrane of influenza A, with similarly anomalous diffusion of lipids. Biophysical robustness of the envelope may confer resilience to environmental perturbations. The dengue virus envelope is a lipid bilayer plus an outer layer of membrane proteins The structures of the proteins plus lipidomics data were used to model the envelope Microsecond MD simulations revealed the dynamic behavior of the lipid bilayer Protein interactions confer “raft-like” robustness on a cholesterol-free membrane
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Affiliation(s)
- Tyler Reddy
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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44
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Dynamic Viral Glycoprotein Machines: Approaches for Probing Transient States That Drive Membrane Fusion. Viruses 2016; 8:v8010015. [PMID: 26761026 PMCID: PMC4728575 DOI: 10.3390/v8010015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 12/11/2015] [Accepted: 12/31/2015] [Indexed: 01/10/2023] Open
Abstract
The fusion glycoproteins that decorate the surface of enveloped viruses undergo dramatic conformational changes in the course of engaging with target cells through receptor interactions and during cell entry. These refolding events ultimately drive the fusion of viral and cellular membranes leading to delivery of the genetic cargo. While well-established methods for structure determination such as X-ray crystallography have provided detailed structures of fusion proteins in the pre- and post-fusion fusion states, to understand mechanistically how these fusion glycoproteins perform their structural calisthenics and drive membrane fusion requires new analytical approaches that enable dynamic intermediate states to be probed. Methods including structural mass spectrometry, small-angle X-ray scattering, and electron microscopy have begun to provide new insight into pathways of conformational change and fusion protein function. In combination, the approaches provide a significantly richer portrait of viral fusion glycoprotein structural variation and fusion activation as well as inhibition by neutralizing agents. Here recent studies that highlight the utility of these complementary approaches will be reviewed with a focus on the well-characterized influenza virus hemagglutinin fusion glycoprotein system.
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45
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Ivanovic T, Harrison SC. Distinct functional determinants of influenza hemagglutinin-mediated membrane fusion. eLife 2015; 4:e11009. [PMID: 26613408 PMCID: PMC4755761 DOI: 10.7554/elife.11009] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/26/2015] [Indexed: 11/13/2022] Open
Abstract
Membrane fusion is the critical step for infectious cell penetration by enveloped viruses. We have previously used single-virion measurements of fusion kinetics to study the molecular mechanism of influenza-virus envelope fusion. Published data on fusion inhibition by antibodies to the 'stem' of influenza virus hemagglutinin (HA) now allow us to incorporate into simulations the provision that some HAs are inactive. We find that more than half of the HAs are unproductive even for virions with no bound antibodies, but that the overall mechanism is extremely robust. Determining the fraction of competent HAs allows us to determine their rates of target-membrane engagement. Comparison of simulations with data from H3N2 and H1N1 viruses reveals three independent functional variables of HA-mediated membrane fusion closely linked to neutralization susceptibility. Evidence for compensatory changes in the evolved mechanism sets the stage for studies aiming to define the molecular constraints on HA evolvability.
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Affiliation(s)
- Tijana Ivanovic
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, United States.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States.,Department of Biochemistry, Brandeis University, Waltham, United States
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States.,Howard Hughes Medical Institute, Harvard Medical School, Boston, United States
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46
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Zhang X, Dhawane AN, Sweeney J, He Y, Vasireddi M, Iyer SS. Electrochemical assay to detect influenza viruses and measure drug susceptibility. Angew Chem Int Ed Engl 2015; 54:5929-32. [PMID: 25823546 PMCID: PMC5453671 DOI: 10.1002/anie.201412164] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 01/29/2015] [Indexed: 12/17/2022]
Abstract
An electrochemical assay has been designed to rapidly diagnose influenza viruses. Exposure of a glucose-bearing substrate to influenza viruses or its enzyme, neuraminidase (NA), releases glucose, which was detected amperometrically. Two methods were used to detect released glucose. First, we used a standard glucose blood meter to detect two viral NAs and three influenza strains. We also demonstrated drug susceptibility of two antivirals, Zanamivir and Oseltamivir, using the assay. Finally, we used disposable test strips to detect nineteen H1N1 and H3N2 influenza strains using this assay in one hour. The limit and range of detection of this first generation assay is 10(2) and 10(2)-10(8) plaque forming units (pfu), respectively. Current user-friendly glucose meters can be repurposed to detect influenza viruses.
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Affiliation(s)
| | | | | | | | | | - Suri S. Iyer
- Xiaohu Zhang, Dr. Abasaheb N. Dhawane, Joyce Sweeney, Dr. Yun He, Dr. Mugdha Vasireddi and Prof. Suri S. Iyer 788 Petit Science Center, Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA - 30302.
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47
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Fontana J, Steven AC. Influenza virus-mediated membrane fusion: Structural insights from electron microscopy. Arch Biochem Biophys 2015; 581:86-97. [PMID: 25958107 DOI: 10.1016/j.abb.2015.04.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 04/21/2015] [Accepted: 04/27/2015] [Indexed: 12/26/2022]
Abstract
Influenza virus, the causative agent of flu, enters the host cell by endocytosis. The low pH encountered inside endosomes triggers conformational changes in the viral glycoprotein hemagglutinin (HA), that mediate fusion of the viral and cellular membranes. This releases the viral genome into the cytoplasm of the infected cell, establishing the onset of the replication cycle. To investigate the structural basis of HA-mediated membrane fusion, a number of techniques have been employed. These include X-ray crystallography, which has provided atomic models of the HA ectodomain in its initial (pre-fusion) state and of part of HA in its final (post-fusion) state. However, this left an information deficit concerning many other aspects of the fusion process. Electron microscopy (EM) approaches are helping to fill this void. For example, influenza virions at neutral pH have been imaged by cryo-EM and cryo-electron tomography (cryo-ET); thin section EM has shown that influenza viruses enter the cell by endocytosis; the large-scale structural changes in HA when virions are exposed to low pH (pre-fusion to post-fusion states) have been visualized by negative staining and cryo-EM; acidification also induces structural changes in the M1 matrix layer and its separation from the viral envelope; intermediate HA conformations between its pre- and post-fusion states have been detected by cryo-ET supplemented with subtomogram averaging; and fusion of influenza virions with liposomes has been visualized by cryo-ET. In this review, we survey EM-based contributions towards the characterization of influenza virus-mediated membrane fusion and anticipate the potential for future developments.
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Affiliation(s)
- Juan Fontana
- Laboratory of Structural Biology Research, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Alasdair C Steven
- Laboratory of Structural Biology Research, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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48
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Zhang X, Dhawane AN, Sweeney J, He Y, Vasireddi M, Iyer SS. Electrochemical Assay to Detect Influenza Viruses and Measure Drug Susceptibility. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201412164] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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49
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Reddy T, Shorthouse D, Parton DL, Jefferys E, Fowler PW, Chavent M, Baaden M, Sansom MSP. Nothing to sneeze at: a dynamic and integrative computational model of an influenza A virion. Structure 2015; 23:584-597. [PMID: 25703376 PMCID: PMC4353694 DOI: 10.1016/j.str.2014.12.019] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/09/2014] [Accepted: 12/17/2014] [Indexed: 11/28/2022]
Abstract
The influenza virus is surrounded by an envelope composed of a lipid bilayer and integral membrane proteins. Understanding the structural dynamics of the membrane envelope provides biophysical insights into aspects of viral function, such as the wide-ranging survival times of the virion in different environments. We have combined experimental data from X-ray crystallography, nuclear magnetic resonance spectroscopy, cryo-electron microscopy, and lipidomics to build a model of the intact influenza A virion. This is the basis of microsecond-scale coarse-grained molecular dynamics simulations of the virion, providing simulations at different temperatures and with varying lipid compositions. The presence of the Forssman glycolipid alters a number of biophysical properties of the virion, resulting in reduced mobility of bilayer lipid and protein species. Reduced mobility in the virion membrane may confer physical robustness to changes in environmental conditions. Our simulations indicate that viral spike proteins do not aggregate and thus are competent for multivalent immunoglobulin G interactions.
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Affiliation(s)
- Tyler Reddy
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - David Shorthouse
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Daniel L Parton
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Elizabeth Jefferys
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Philip W Fowler
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Matthieu Chavent
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Marc Baaden
- Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique, UPR9080, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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50
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Le TT, Adamiak B, Benton DJ, Johnson CJ, Sharma S, Fenton R, McCauley JW, Iqbal M, Cass AEG. Aptamer-based biosensors for the rapid visual detection of flu viruses. Chem Commun (Camb) 2014; 50:15533-6. [PMID: 25354585 DOI: 10.1039/c4cc07888h] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
RNA aptamers showing affinity and specificity for different strains of human influenza virus were assembled onto gold nanoparticles that subsequently formed a gold nanoshell (AuNS) around the viral envelope. These shells could be visualised by transmission electron microscopy (TEM). Changes in size and structure of the AuNS coated virus can be used to detect the viruses. We show that sedimentation with a low cost centrifuge and visual determination can detect 3 × 10(8) viral particles.
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Affiliation(s)
- T T Le
- Department of Chemistry, Imperial College London, UK.
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