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Zhang M, Roldan-Hernandez L, Boehm A. Persistence of human respiratory viral RNA in wastewater-settled solids. Appl Environ Microbiol 2024; 90:e0227223. [PMID: 38501669 PMCID: PMC11022535 DOI: 10.1128/aem.02272-23] [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: 12/16/2023] [Accepted: 03/01/2024] [Indexed: 03/20/2024] Open
Abstract
Wastewater-based epidemiology has emerged as a valuable tool for monitoring respiratory viral diseases within communities by analyzing concentrations of viral nucleic-acids in wastewater. However, little is known about the fate of respiratory virus nucleic-acids in wastewater. Two important fate processes that may modulate their concentrations in wastewater as they move from household drains to the point of collection include sorption or partitioning to wastewater solids and degradation. This study investigated the decay kinetics of genomic nucleic-acids of seven human respiratory viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respiratory syncytial virus (RSV), human coronavirus (HCoV)-OC43, HCoV-229E, HCoV-NL63, human rhinovirus (HRV), and influenza A virus (IAV), as well as pepper mild mottle virus (PMMoV) in wastewater solids. Viruses (except for PMMoV) were spiked into wastewater solids and their concentrations were followed for 50 days at three different temperatures (4°C, 22°C, and 37°C). Viral genomic RNA decayed following first-order kinetics with decay rate constants k from 0 to 0.219 per day. Decay rate constants k were not different from 0 for all targets in solids incubated at 4°C; k values were largest at 37°C and at this temperature, k values were similar across nucleic-acid targets. Regardless of temperature, there was limited viral RNA decay, with an estimated 0% to 20% reduction, over the typical residence times of sewage in the piped systems between input and collection point (<1 day). The k values reported herein can be used directly in fate and transport models to inform the interpretation of measurements made during wastewater surveillance.IMPORTANCEUnderstanding whether or not the RNA targets quantified for wastewater-based epidemiology (WBE) efforts decay during transport between drains and the point of sample collection is critical for data interpretation. Here we show limited decay of viral RNA targets typically measured for respiratory disease WBE.
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Affiliation(s)
- Mengyang Zhang
- Department of Civil and Environmental Engineering, School of Engineering and Doerr School of Sustainability, Stanford University, Stanford, California, USA
| | - Laura Roldan-Hernandez
- Department of Civil and Environmental Engineering, School of Engineering and Doerr School of Sustainability, Stanford University, Stanford, California, USA
| | - Alexandria Boehm
- Department of Civil and Environmental Engineering, School of Engineering and Doerr School of Sustainability, Stanford University, Stanford, California, USA
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2
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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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3
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Kwasnik M, Rola J, Rozek W. Influenza D in Domestic and Wild Animals. Viruses 2023; 15:2433. [PMID: 38140674 PMCID: PMC10748149 DOI: 10.3390/v15122433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Influenza D virus (IDV) infections have been observed in animals worldwide, confirmed through both serological and molecular tests, as well as virus isolation. IDV possesses unique properties that distinguish it from other influenza viruses, primarily attributed to the hemagglutinin-esterase fusion (HEF) surface glycoprotein, which determines the virus' tropism and wide host range. Cattle are postulated to be the reservoir of IDV, and the virus is identified as one of the causative agents of bovine respiratory disease (BRD) syndrome. Animals associated with humans and susceptible to IDV infection include camels, pigs, small ruminants, and horses. Notably, high seroprevalence towards IDV, apart from cattle, is also observed in camels, potentially constituting a reservoir of the virus. Among wild and captive animals, IDV infections have been confirmed in feral pigs, wild boars, deer, hedgehogs, giraffes, wildebeests, kangaroos, wallabies, and llamas. The transmission potential and host range of IDV may contribute to future viral differentiation. It has been confirmed that influenza D may pose a threat to humans as a zoonosis, with seroprevalence noted in people with professional contact with cattle.
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Affiliation(s)
| | | | - Wojciech Rozek
- Department of Virology, National Veterinary Research Institute, Al. Partyzantow 57, 24-100 Pulawy, Poland; (M.K.); (J.R.)
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4
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Saka N, Ohta K, Kolakofsky D, Nishio M. The bipartite promoter of Orthonairovirus hazaraense large segment. J Virol 2023; 97:e0091823. [PMID: 37916836 PMCID: PMC10688357 DOI: 10.1128/jvi.00918-23] [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: 06/21/2023] [Accepted: 10/03/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE The realization that segmented negative-strand RNA virus genome ribonucleoproteins are never free as their RNA ends are always bound to the viral polymerase has highlighted the problem of how these genome segments are replicated and express their mRNAs while their RNA ends remain associated with the polymerase throughout the cycles of RNA synthesis. This study of the length and nucleotide composition of the Orthonairovirus hazaraense L segment-specific double-stranded RNA (dsRNA) promoter element (the promoter duplex) provides insight into how its mRNA might be initiated and suggests that this promoter element acts via its separated single strands as well as via dsRNA.
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Affiliation(s)
- Naoki Saka
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Keisuke Ohta
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Daniel Kolakofsky
- Department of Microbiology and Molecular Medicine, University of Geneva School of Medicine, Geneva, Switzerland
| | - Machiko Nishio
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
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5
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Ng BWL, Scheeff S, Xeque Amada J. Making it hard to replicate. eLife 2023; 12:88044. [PMID: 37114773 PMCID: PMC10147374 DOI: 10.7554/elife.88044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
Understanding how to harden liquid condensates produced by influenza A virus could accelerate the development of novel antiviral drugs.
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6
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Chakraborty S, Chauhan A. Fighting the flu: a brief review on anti-influenza agents. Biotechnol Genet Eng Rev 2023:1-52. [PMID: 36946567 DOI: 10.1080/02648725.2023.2191081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The influenza virus causes one of the most prevalent and lethal infectious viral diseases of the respiratory system; the disease progression varies from acute self-limiting mild fever to disease chronicity and death. Although both the preventive and treatment measures have been vital in protecting humans against seasonal epidemics or sporadic pandemics, there are several challenges to curb the influenza virus such as limited or poor cross-protection against circulating virus strains, moderate protection in immune-compromised patients, and rapid emergence of resistance. Currently, there are four US-FDA-approved anti-influenza drugs to treat flu infection, viz. Rapivab, Relenza, Tamiflu, and Xofluza. These drugs are classified based on their mode of action against the viral replication cycle with the first three being Neuraminidase inhibitors, and the fourth one targeting the viral polymerase. The emergence of the drug-resistant strains of influenza, however, underscores the need for continuous innovation towards development and discovery of new anti-influenza agents with enhanced antiviral effects, greater safety, and improved tolerability. Here in this review, we highlighted commercially available antiviral agents besides those that are at different stages of development including under clinical trials, with a brief account of their antiviral mechanisms.
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Affiliation(s)
| | - Ashwini Chauhan
- Department of Microbiology, Tripura University, Agartala, India
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7
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Functional Importance of the Hydrophobic Residue 362 in Influenza A PB1 Subunit. Viruses 2023; 15:v15020396. [PMID: 36851609 PMCID: PMC9967172 DOI: 10.3390/v15020396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/26/2023] [Accepted: 01/28/2023] [Indexed: 01/31/2023] Open
Abstract
PB1, acting as the catalytic subunit of the influenza polymerase, has numerous sequentially and structurally conserved regions. It has been observed that the slight modification of residues in PB1 would greatly affect the polymerase activity and even host adaptation ability. Here, we identified a critical residue, 362M, on the polymerase activity and virus replication. By means of the minireplicon assay, we assured the importance of the hydrophobicity of PB1 362, and the possibility that the size and charge of the side chain might directly interfere with the polymerase function. We also proposed a hydrophobic core between the PA-arch and the PB1 β-hairpin motifs and showed the importance of the core to the polymerase function.
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Influenza Treatment: Limitations of Antiviral Therapy and Advantages of Drug Combination Therapy. Microorganisms 2023; 11:microorganisms11010183. [PMID: 36677475 PMCID: PMC9865513 DOI: 10.3390/microorganisms11010183] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/23/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023] Open
Abstract
Influenza infection is serious and debilitating for humans and animals. The influenza virus undergoes incessant mutation, segment recombination, and genome reassortment. As a result, new epidemics and pandemics are expected to emerge, making the elimination challenging of the disease. Antiviral therapy has been used for the treatment of influenza since the development of amantadine in the 1960s; however, its use is hampered by the emergence of novel strains and the development of drug resistance. Thus, combinational therapy with two or more antivirals or immunomodulators with different modes of action is the optimal strategy for the effective treatment of influenza infection. In this review, we describe current options for combination therapy, their performance, and constraints imposed by resistance, calling attention to the advantages of combination therapy against severe influenza infections. We also discuss the challenges of influenza therapy and the limitations of approved antiviral drugs.
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9
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Madsen JJ, Rossman JS. Cholesterol and M2 Rendezvous in Budding and Scission of Influenza A Virus. Subcell Biochem 2023; 106:441-459. [PMID: 38159237 DOI: 10.1007/978-3-031-40086-5_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The cholesterol of the host cell plasma membrane and viral M2 protein plays a crucial role in multiple stages of infection and replication of the influenza A virus. Cholesterol is required for the formation of heterogeneous membrane microdomains (or rafts) in the budozone of the host cell that serves as assembly sites for the viral components. The raft microstructures act as scaffolds for several proteins. Cholesterol may further contribute to the mechanical forces necessary for membrane scission in the last stage of budding and help to maintain the stability of the virus envelope. The M2 protein has been shown to cause membrane scission in model systems by promoting the formation of curved lipid bilayer structures that, in turn, can lead to membrane vesicles budding off or scission intermediates. Membrane remodeling by M2 is intimately linked with cholesterol as it affects local lipid composition, fluidity, and stability of the membrane. Thus, both cholesterol and M2 protein contribute to the efficient and proper release of newly formed influenza viruses from the virus-infected cells.
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Affiliation(s)
- Jesper J Madsen
- Global and Planetary Health, Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, FL, USA.
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
| | - Jeremy S Rossman
- School of Biosciences, University of Kent, Canterbury, Kent, UK
- Research-Aid Networks, Chicago, IL, USA
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10
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Expansion of Single Chains Released from a Spherical Cavity. Polymers (Basel) 2022; 15:polym15010198. [PMID: 36616547 PMCID: PMC9824584 DOI: 10.3390/polym15010198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/18/2022] [Accepted: 12/23/2022] [Indexed: 01/03/2023] Open
Abstract
A two-stage model is developed to explain the phenomena of chain expansion, released from a confining cavity. In the first stage, the chain is assumed to expand as a sphere, while in the second stage it expands like a coil. The kinetic equations for the variation of chain size are derived in the two stages by balancing the rate of the free energy change with the rate of the energy dissipation. Langevin dynamics simulations are then performed to examine the theory. We find that the expansion process is dominated by the second stage and the evolution of chain size follows, mainly, the predicted curve for coil expansion, which depends on the chain length and is not sensitive to the confining volume fraction. It permits to define the expansion time for the process. Further study reveals that the chain does undergo a spherical expansion in the first stage with the characteristic time much shorter than the one for the second stage. As a consequence, the first-stage variation of chain size can be regarded as an add-on to the principal curve of expansion designated by the second stage. The scaling behaviors and the associated scaling exponents are analyzed in details. The simulation results well support the theory.
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11
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Chavda V, Bezbaruah R, Kalita T, Sarma A, Devi JR, Bania R, Apostolopoulos V. Variant influenza: connecting the missing dots. Expert Rev Anti Infect Ther 2022; 20:1567-1585. [PMID: 36346383 DOI: 10.1080/14787210.2022.2144231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND In June 2009, the World Health Organization declared a new pandemic, the 2009 swine influenza pandemic (swine flu). The symptoms of the swine flu pandemic causing strain were comparable to most of the symptoms noted by seasonal influenza. AREA COVERED Zoonotic viruses that caused the swine flu pandemic and its preventive measures. EXPERT OPINION As per Centers for Disease Control and Prevention (CDC), the clinical manifestations in humans produced by the 2009 H1N1 'swine flu' virus were equivalent to the manifestations caused by related flu strains. The H1N1 vaccination was the most successful prophylactic measure since it prevented the virus from spreading and reduced the intensity and consequences of the pandemic. Despite the availability of therapeutics, the ongoing evolution and appearance of new strains have made it difficult to develop effective vaccines and therapies. Currently, the CDC recommends yearly flu immunization for those aged 6 months and above. The lessons learned from the A/2009/H1N1 pandemic in 2009 indicated that readiness of mankind toward new illnesses caused by mutant viral subtypes that leap from animals to people must be maintained.
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Affiliation(s)
- Vivek Chavda
- Department of Pharmaceutics and Pharmaceutical Technology, L M College of Pharmacy, Ahmedabad, India
| | - Rajashri Bezbaruah
- Department of Pharmaceutical Sciences, Faculty of Science and Engineering, Dibrugarh University, Dibrugarh, India
| | - Tutumoni Kalita
- Department of Pharmaceutical Chemistry, Regional College of Pharmaceutical Sciences, RIPT Group of Institution, Sonapur, Guwahati, India
| | - Anupam Sarma
- Department of Pharmaceutics, Girijananda Chowdhury Institute of Pharmaceutical Science, Hatkhowapara, Azara, Guwahati, Assam, India
| | - Juti Rani Devi
- NETES Institute of Pharmaceutical Science, Mirza, Guwahati, India
| | - Ratnali Bania
- Pratiksha Institute of Pharmaceutical Sciences, India
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12
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Understanding the Role of HLA Class I Molecules in the Immune Response to Influenza Infection and Rational Design of a Peptide-Based Vaccine. Viruses 2022; 14:v14112578. [PMID: 36423187 PMCID: PMC9695287 DOI: 10.3390/v14112578] [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] [Received: 10/08/2022] [Revised: 11/04/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
Influenza A virus is a respiratory pathogen that is responsible for regular epidemics and occasional pandemics that result in substantial damage to life and the economy. The yearly reformulation of trivalent or quadrivalent flu vaccines encompassing surface glycoproteins derived from the current circulating strains of the virus does not provide sufficient cross-protection against mismatched strains. Unlike the current vaccines that elicit a predominant humoral response, vaccines that induce CD8+ T cells have demonstrated a capacity to provide cross-protection against different influenza strains, including novel influenza viruses. Immunopeptidomics, the mass spectrometric identification of human-leukocyte-antigen (HLA)-bound peptides isolated from infected cells, has recently provided key insights into viral peptides that can serve as potential T cell epitopes. The critical elements required for a strong and long-living CD8+ T cell response are related to both HLA restriction and the immunogenicity of the viral peptide. This review examines the importance of HLA and the viral immunopeptidome for the design of a universal influenza T-cell-based vaccine.
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13
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Stincarelli MA, Rocca A, Antonelli A, Rossolini GM, Giannecchini S. Antiviral Activity of Oligonucleotides Targeting the SARS-CoV-2 Genomic RNA Stem-Loop Sequences within the 3'-End of the ORF1b. Pathogens 2022; 11:1286. [PMID: 36365037 PMCID: PMC9696570 DOI: 10.3390/pathogens11111286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/27/2022] [Accepted: 10/29/2022] [Indexed: 08/30/2023] Open
Abstract
Increased evidence shows vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibited no long-term efficacy and limited worldwide availability, while existing antivirals and treatment options have only limited efficacy. In this study, the main objective was the development of antiviral strategies using nucleic acid-based molecules. To this purpose, partially overlapped 6-19-mer phosphorothioate deoxyoligonucleotides (S-ONs) designed on the SARS-CoV-2 genomic RNA stem-loop packaging sequences within the 3' end of the ORF1b were synthetized using the direct and complementary sequence. Among the S-ONs tested, several oligonucleotides exhibited a fifty percent inhibitory concentration antiviral activity ranging from 0.27 to 34 μM, in the absence of cytotoxicity. The S-ON with a scrambled sequence used in the same conditions was not active. Moreover, selected 10-mer S-ONs were tested using different infectious doses and against different SARS-CoV-2 variants, showing comparable antiviral activity that was abrogated when the central sequence was mutated. Experiments to evaluate the intracellular functional target localization of the S-ON inhibitory activity were also performed. Collectively the data indicate that the SARS-CoV-2 packaging region in the 3' end of the ORF1b may be a promising target candidate for further investigation to develop innovative nucleic-acid-based antiviral therapy.
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Affiliation(s)
| | - Arianna Rocca
- Department of Experimental and Clinical Medicine, University of Florence, I-50134 Florence, Italy
| | - Alberto Antonelli
- Department of Experimental and Clinical Medicine, University of Florence, I-50134 Florence, Italy
| | - Gian Maria Rossolini
- Department of Experimental and Clinical Medicine, University of Florence, I-50134 Florence, Italy
- Microbiology and Virology Unit, Florence Careggi University Hospital, I-50134 Florence, Italy
| | - Simone Giannecchini
- Department of Experimental and Clinical Medicine, University of Florence, I-50134 Florence, Italy
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14
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Programmable antivirals targeting critical conserved viral RNA secondary structures from influenza A virus and SARS-CoV-2. Nat Med 2022; 28:1944-1955. [PMID: 35982307 PMCID: PMC10132811 DOI: 10.1038/s41591-022-01908-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/20/2022] [Indexed: 12/18/2022]
Abstract
Influenza A virus's (IAV's) frequent genetic changes challenge vaccine strategies and engender resistance to current drugs. We sought to identify conserved and essential RNA secondary structures within IAV's genome that are predicted to have greater constraints on mutation in response to therapeutic targeting. We identified and genetically validated an RNA structure (packaging stem-loop 2 (PSL2)) that mediates in vitro packaging and in vivo disease and is conserved across all known IAV isolates. A PSL2-targeting locked nucleic acid (LNA), administered 3 d after, or 14 d before, a lethal IAV inoculum provided 100% survival in mice, led to the development of strong immunity to rechallenge with a tenfold lethal inoculum, evaded attempts to select for resistance and retained full potency against neuraminidase inhibitor-resistant virus. Use of an analogous approach to target SARS-CoV-2, prophylactic administration of LNAs specific for highly conserved RNA structures in the viral genome, protected hamsters from efficient transmission of the SARS-CoV-2 USA_WA1/2020 variant. These findings highlight the potential applicability of this approach to any virus of interest via a process we term 'programmable antivirals', with implications for antiviral prophylaxis and post-exposure therapy.
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15
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Ling YH, Wang H, Han MQ, Wang D, Hu YX, Zhou K, Li Y. Nucleoporin 85 interacts with influenza A virus PB1 and PB2 to promote its replication by facilitating nuclear import of ribonucleoprotein. Front Microbiol 2022; 13:895779. [PMID: 36051755 PMCID: PMC9426659 DOI: 10.3389/fmicb.2022.895779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/29/2022] [Indexed: 11/30/2022] Open
Abstract
Transcription and replication of the influenza A virus (IAV) genome take place in the nucleus of infected cells, which rely on host factors to aid viral ribonucleoprotein (vRNP) to cross the nuclear pore complex (NPC) and complete the bidirectional nucleocytoplasmic trafficking. Here, we showed that nucleoporin 85 (NUP85), a component of NPC, interacted with RNP subunits polymerase basic 1 (PB1) and polymerase basic 2 (PB2) in an RNA-dependent manner during IAV infection. Knockdown of NUP85 delayed the nuclear import of vRNP, PB1 and PB2, inhibiting polymerase activity and ultimately suppressing viral replication. Further analysis revealed that NUP85 assisted the binding of PB1 to nuclear transport factor Ran-binding protein 5 (RanBP5) and the binding of PB2 to nuclear transport factor importin α1 and importin α7. We also found that NUP85 expression was downregulated upon IAV infection. Together, our study demonstrated that NUP85 positively regulated IAV infection by interacting with viral PB1 and PB2, which may provide new insight into the process of vRNP nuclear import and a novel target for effective antivirals.
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Affiliation(s)
- Yue-Huan Ling
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Hao Wang
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Mei-Qing Han
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Di Wang
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Yi-Xiang Hu
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
- Hainan Institute, Zhejiang University, Sanya, Hainan, China
| | - Kun Zhou
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Yan Li
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
- Hainan Institute, Zhejiang University, Sanya, Hainan, China
- Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
- *Correspondence: Yan Li,
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16
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p21 restricts influenza A virus by perturbing the viral polymerase complex and upregulating type I interferon signaling. PLoS Pathog 2022; 18:e1010295. [PMID: 35180274 PMCID: PMC8920271 DOI: 10.1371/journal.ppat.1010295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/14/2022] [Accepted: 01/20/2022] [Indexed: 11/19/2022] Open
Abstract
Many cellular genes and networks induced in human lung epithelial cells infected with the influenza virus remain uncharacterized. Here, we find that p21 levels are elevated in response to influenza A virus (IAV) infection, which is independent of p53. Silencing, pharmacological inhibition or deletion of p21 promotes virus replication in vitro and in vivo, indicating that p21 is an influenza restriction factor. Mechanistically, p21 binds to the C-terminus of IAV polymerase subunit PA and competes with PB1 to limit IAV polymerase activity. Besides, p21 promotes IRF3 activation by blocking K48-linked ubiquitination degradation of HO-1 to enhance type I interferons expression. Furthermore, a synthetic p21 peptide (amino acids 36 to 43) significantly inhibits IAV replication in vitro and in vivo. Collectively, our findings reveal that p21 restricts IAV by perturbing the viral polymerase complex and activating the host innate immune response, which may aid the design of desperately needed new antiviral therapeutics. Influenza A virus (IAV) poses a continuous threat to public health and economic stability. The ribonucleoprotein (RNP) of IAV is responsible for the transcription and replication of the viral RNA. These processes require interplay between host factors and RNP components. Here, we report that p21 can be activated by IAV infection and is controlled by a p53-independent pathway. We demonstrate that p21 directly binds to the viral polymerase acidic protein and limits IAV polymerase activity through disrupting the formation of the ribonucleoprotein complex. Additionally, p21 activation promotes IRF3 activation by blocking K48-linked polyubiquitination degradation of HO-1, thereby activating the type I interferon pathway. We further identify an 8-amino-acid peptide of p21 as the minimum motif that effectively inhibits IAV replication and presents therapeutic efficacy both in vitro and in vivo. Thus, our studies not only identify p21 as an antiviral protein, but also provide mechanistic insight to facilitate drug development.
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Bu L, Chen B, Xing L, Cai X, Liang S, Zhang L, Wang X, Song W. Generation of a pdmH1N1 2018 Influenza A Reporter Virus Carrying a mCherry Fluorescent Protein in the PA Segment. Front Cell Infect Microbiol 2022; 11:827790. [PMID: 35127568 PMCID: PMC8811159 DOI: 10.3389/fcimb.2021.827790] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 12/31/2021] [Indexed: 11/13/2022] Open
Abstract
Influenza A virus (IAV) is a major human pathogen associated with significant morbidity and mortality worldwide. Through serial passage in mice, we generated a recombinant pdmH1N1 2009 IAV, A/Guangdong/GLW/2018 (GLW/18-MA), which encodes an mCherry gene fused to the C-terminal of a polymerase acidic (PA) segment and demonstrated comparable growth kinetics to the wild-type. Nine mutations were identified in the GLW/18-MA genome: PA (I61M, E351G, and G631S), NP (E292G), HA1 (T164I), HA2 (N117S and P160S), NA (W61R), and NEP (K44R). The recombinant IAV reporter expresses mCherry, a red fluorescent protein, at a high level and maintains its genetic integrity after five generations of serial passages in Madin-Darby Canine Kidney cells (MDCK) cells. Moreover, the imaging is noninvasive and permits the monitoring of infection in living mice. Treatment with oseltamivir or baicalin followed by infection with the reporter IAV led to a decrease in fluorescent protein signal in living mice. This result demonstrates that the IAV reporter virus is a powerful tool to study viral pathogenicity and transmission and to develop and evaluate novel anti-viral drugs, inhibitors, and vaccines in the future.
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Affiliation(s)
- Ling Bu
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Boqian Chen
- Artemisinin Research Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lei Xing
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Xuejun Cai
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Shuhua Liang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Liying Zhang
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, China
| | - Xinhua Wang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Artemisinin Research Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wenjun Song
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- State Key Laboratory for Emerging Infectious Diseases, Department of Microbiology, and the Research Center of Infection and Immunology, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
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18
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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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19
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Pelz L, Rüdiger D, Dogra T, Alnaji FG, Genzel Y, Brooke CB, Kupke SY, Reichl U. Semi-continuous Propagation of Influenza A Virus and Its Defective Interfering Particles: Analyzing the Dynamic Competition To Select Candidates for Antiviral Therapy. J Virol 2021; 95:e0117421. [PMID: 34550771 PMCID: PMC8610589 DOI: 10.1128/jvi.01174-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/19/2021] [Indexed: 12/26/2022] Open
Abstract
Defective interfering particles (DIPs) of influenza A virus (IAV) are naturally occurring mutants that have an internal deletion in one of their eight viral RNA (vRNA) segments, rendering them propagation-incompetent. Upon coinfection with infectious standard virus (STV), DIPs interfere with STV replication through competitive inhibition. Thus, DIPs are proposed as potent antivirals for treatment of the influenza disease. To select corresponding candidates, we studied de novo generation of DIPs and propagation competition between different defective interfering (DI) vRNAs in an STV coinfection scenario in cell culture. A small-scale two-stage cultivation system that allows long-term semi-continuous propagation of IAV and its DIPs was used. Strong periodic oscillations in virus titers were observed due to the dynamic interaction of DIPs and STVs. Using next-generation sequencing, we detected a predominant formation and accumulation of DI vRNAs on the polymerase-encoding segments. Short DI vRNAs accumulated to higher fractions than longer ones, indicating a replication advantage, yet an optimum fragment length was observed. Some DI vRNAs showed breaking points in a specific part of their bundling signal (belonging to the packaging signal), suggesting its dispensability for DI vRNA propagation. Over a total cultivation time of 21 days, several individual DI vRNAs accumulated to high fractions, while others decreased. Using reverse genetics for IAV, purely clonal DIPs derived from highly replicating DI vRNAs were generated. We confirm that these DIPs exhibit a superior in vitro interfering efficacy compared to DIPs derived from lowly accumulated DI vRNAs and suggest promising candidates for efficacious antiviral treatment. IMPORTANCE Defective interfering particles (DIPs) emerge naturally during viral infection and typically show an internal deletion in the viral genome. Thus, DIPs are propagation-incompetent. Previous research suggests DIPs as potent antiviral compounds for many different virus families due to their ability to interfere with virus replication by competitive inhibition. For instance, the administration of influenza A virus (IAV) DIPs resulted in a rescue of mice from an otherwise lethal IAV dose. Moreover, no apparent toxic effects were observed when only DIPs were administered to mice and ferrets. IAV DIPs show antiviral activity against many different IAV strains, including pandemic and highly pathogenic avian strains, and even against nonhomologous viruses, such as SARS-CoV-2, by stimulation of innate immunity. Here, we used a cultivation/infection system, which exerted selection pressure toward accumulation of highly competitive IAV DIPs. These DIPs showed a superior interfering efficacy in vitro, and we suggest them for effective antiviral therapy.
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Affiliation(s)
- Lars Pelz
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
| | - Daniel Rüdiger
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
| | - Tanya Dogra
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
| | - Fadi G. Alnaji
- University of Illinois at Urbana-Champaign, Department of Microbiology, Urbana, Illinois, USA
| | - Yvonne Genzel
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
| | - Christopher B. Brooke
- University of Illinois at Urbana-Champaign, Department of Microbiology, Urbana, Illinois, USA
| | - Sascha Y. Kupke
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
| | - Udo Reichl
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
- Otto-von-Guericke-University Magdeburg, Bioprocess Engineering, Magdeburg, Germany
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20
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Orr-Burks N, Murray J, Todd KV, Bakre A, Tripp RA. Drug repositioning of Clopidogrel or Triamterene to inhibit influenza virus replication in vitro. PLoS One 2021; 16:e0259129. [PMID: 34714852 PMCID: PMC8555795 DOI: 10.1371/journal.pone.0259129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/13/2021] [Indexed: 12/22/2022] Open
Abstract
Influenza viruses cause respiratory tract infections and substantial health concerns. Infection may result in mild to severe respiratory disease associated with morbidity and some mortality. Several anti-influenza drugs are available, but these agents target viral components and are susceptible to drug resistance. There is a need for new antiviral drug strategies that include repurposing of clinically approved drugs. Drugs that target cellular machinery necessary for influenza virus replication can provide a means for inhibiting influenza virus replication. We used RNA interference screening to identify key host cell genes required for influenza replication, and then FDA-approved drugs that could be repurposed for targeting host genes. We examined the effects of Clopidogrel and Triamterene to inhibit A/WSN/33 (EC50 5.84 uM and 31.48 uM, respectively), A/CA/04/09 (EC50 6.432 uM and 3.32 uM, respectively), and B/Yamagata/16/1988 (EC50 0.28 uM and 0.11 uM, respectively) replication. Clopidogrel and Triamterene provide a druggable approach to influenza treatment across multiple strains and subtypes.
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Affiliation(s)
- Nichole Orr-Burks
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Jackelyn Murray
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Kyle V. Todd
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Abhijeet Bakre
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Ralph A. Tripp
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
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21
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Tomaszewska M, Szabat M, Zielińska K, Kierzek R. Identification and Structural Aspects of G-Quadruplex-Forming Sequences from the Influenza A Virus Genome. Int J Mol Sci 2021; 22:6031. [PMID: 34199658 PMCID: PMC8199785 DOI: 10.3390/ijms22116031] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/26/2021] [Accepted: 05/31/2021] [Indexed: 12/19/2022] Open
Abstract
Influenza A virus (IAV) causes seasonal epidemics and sporadic pandemics, therefore is an important research subject for scientists around the world. Despite the high variability of its genome, the structure of viral RNA (vRNA) possesses features that remain constant between strains and are biologically important for virus replication. Therefore, conserved structural motifs of vRNA can represent a novel therapeutic target. Here, we focused on the presence of G-rich sequences within the influenza A/California/07/2009(H1N1) genome and their ability to form RNA G-quadruplex structures (G4s). We identified 12 potential quadruplex-forming sequences (PQS) and determined their conservation among the IAV strains using bioinformatics tools. Then we examined the propensity of PQS to fold into G4s by various biophysical methods. Our results revealed that six PQS oligomers could form RNA G-quadruplexes. However, three of them were confirmed to adopt G4 structures by all utilized methods. Moreover, we showed that these PQS motifs are present within segments encoding polymerase complex proteins indicating their possible role in the virus biology.
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Affiliation(s)
- Maria Tomaszewska
- Department of Structural Chemistry and Biology of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland;
| | - Marta Szabat
- Department of Structural Chemistry and Biology of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland;
| | - Karolina Zielińska
- Department of Biomolecular NMR, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland;
| | - Ryszard Kierzek
- Department of Structural Chemistry and Biology of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland;
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22
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Moore RE, Xu LL, Townsend SD. Prospecting Human Milk Oligosaccharides as a Defense Against Viral Infections. ACS Infect Dis 2021; 7:254-263. [PMID: 33470804 DOI: 10.1021/acsinfecdis.0c00807] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In addition to providing maximal nutritional value for neonatal growth and development, human milk functions as an early defense mechanism against invading pathogens. Human milk oligosaccharides (HMOs), which are abundant in human milk, are a diverse group of heterogeneous carbohydrates with wide ranging protective effects. In addition to promoting the colonization of beneficial intestinal flora, HMOs serve as decoy receptors, effectively blocking the attachment of pathogenic bacteria. HMOs also function as bacteriostatic agents, inhibiting the growth of gram-positive bacteria. Based on this precedence, an emerging area in the field has focused on characterizing the antiviral properties of HMOs. Indeed, HMOs have been evaluated as antiviral agents, with many possessing activity against life-threatening infections. This targeted review provides insight into the known glycan-binding interactions between select HMOs and influenza, rotavirus, respiratory syncytial virus, human immunodeficiency virus, and norovirus. Additionally, we review the role of HMOs in preventing necrotizing enterocolitis, an intestinal disease linked to viral infections. We close with a discussion of what is known broadly regarding human milk oligosaccharides and their interactions with coronaviruses.
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Affiliation(s)
- Rebecca E. Moore
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Lianyan L. Xu
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Steven D. Townsend
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
- Vanderbilt Microbiome Initiative, Vanderbilt University, Nashville, Tennessee 37212, United States
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23
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Modeling the
Influenza A
NP-vRNA-Polymerase Complex in Atomic Detail. Biomolecules 2021; 11:biom11010124. [PMID: 33477938 PMCID: PMC7833383 DOI: 10.3390/biom11010124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/07/2021] [Accepted: 01/13/2021] [Indexed: 11/17/2022] Open
Abstract
Seasonal flu is an acute respiratory disease that exacts a massive toll on human populations, healthcare systems and economies. The disease is caused by an enveloped Influenza virus containing eight ribonucleoprotein (RNP) complexes. Each RNP incorporates multiple copies of nucleoprotein (NP), a fragment of the viral genome (vRNA), and a viral RNA-dependent RNA polymerase (POL), and is responsible for packaging the viral genome and performing critical functions including replication and transcription. A complete model of an Influenza RNP in atomic detail can elucidate the structural basis for viral genome functions, and identify potential targets for viral therapeutics. In this work we construct a model of a complete Influenza A RNP complex in atomic detail using multiple sources of structural and sequence information and a series of homology-modeling techniques, including a motif-matching fragment assembly method. Our final model provides a rationale for experimentally-observed changes to viral polymerase activity in numerous mutational assays. Further, our model reveals specific interactions between the three primary structural components of the RNP, including potential targets for blocking POL-binding to the NP-vRNA complex. The methods developed in this work open the possibility of elucidating other functionally-relevant atomic-scale interactions in additional RNP structures and other biomolecular complexes.
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24
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Abd Raman HS, Tan S, August JT, Khan AM. Dynamics of Influenza A (H5N1) virus protein sequence diversity. PeerJ 2020; 7:e7954. [PMID: 32518710 PMCID: PMC7261124 DOI: 10.7717/peerj.7954] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 09/26/2019] [Indexed: 11/20/2022] Open
Abstract
Background Influenza A (H5N1) virus is a global concern with potential as a pandemic threat. High sequence variability of influenza A viruses is a major challenge for effective vaccine design. A continuing goal towards this is a greater understanding of influenza A (H5N1) proteome sequence diversity in the context of the immune system (antigenic diversity), the dynamics of mutation, and effective strategies to overcome the diversity for vaccine design. Methods Herein, we report a comprehensive study of the dynamics of H5N1 mutations by analysis of the aligned overlapping nonamer positions (1–9, 2–10, etc.) of more than 13,000 protein sequences of avian and human influenza A (H5N1) viruses, reported over at least 50 years. Entropy calculations were performed on 9,408 overlapping nonamer position of the proteome to study the diversity in the context of immune system. The nonamers represent the predominant length of the binding cores for peptides recognized by the cellular immune system. To further dissect the sequence diversity, each overlapping nonamer position was quantitatively analyzed for four patterns of sequence diversity motifs: index, major, minor and unique. Results Almost all of the aligned overlapping nonamer positions of each viral proteome exhibited variants (major, minor, and unique) to the predominant index sequence. Each variant motif displayed a characteristic pattern of incidence change in relation to increased total variants. The major variant exhibited a restrictive pyramidal incidence pattern, with peak incidence at 50% total variants. Post this peak incidence, the minor variants became the predominant motif for majority of the positions. Unique variants, each sequence observed only once, were present at nearly all of the nonamer positions. The diversity motifs (index and variants) demonstrated complex inter-relationships, with motif switching being a common phenomenon. Additionally, 25 highly conserved sequences were identified to be shared across viruses of both hosts, with half conserved to several other influenza A subtypes. Discussion The presence of distinct sequences (nonatypes) at nearly all nonamer positions represents a large repertoire of reported viral variants in the proteome, which influence the variability dynamics of the viral population. This work elucidated and provided important insights on the components that make up the viral diversity, delineating inherent patterns in the organization of sequence changes that function in the viral fitness-selection. Additionally, it provides a catalogue of all the mutational changes involved in the dynamics of H5N1 viral diversity for both avian and human host populations. This work provides data relevant for the design of prophylactics and therapeutics that overcome the diversity of the virus, and can aid in the surveillance of existing and future strains of influenza viruses.
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Affiliation(s)
| | - Swan Tan
- School of Data Sciences, Perdana University, Serdang, Selangor, Malaysia.,Institute for Immunology and Informatics, University of Rhode Island, Providence, RI, United States of America
| | - Joseph Thomas August
- School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Asif M Khan
- School of Data Sciences, Perdana University, Serdang, Selangor, Malaysia.,School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America.,Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Beykoz, Istanbul, Turkey
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25
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Host-Virus Interaction: How Host Cells Defend against Influenza A Virus Infection. Viruses 2020; 12:v12040376. [PMID: 32235330 PMCID: PMC7232439 DOI: 10.3390/v12040376] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/19/2020] [Accepted: 03/25/2020] [Indexed: 02/07/2023] Open
Abstract
Influenza A viruses (IAVs) are highly contagious pathogens infecting human and numerous animals. The viruses cause millions of infection cases and thousands of deaths every year, thus making IAVs a continual threat to global health. Upon IAV infection, host innate immune system is triggered and activated to restrict virus replication and clear pathogens. Subsequently, host adaptive immunity is involved in specific virus clearance. On the other hand, to achieve a successful infection, IAVs also apply multiple strategies to avoid be detected and eliminated by the host immunity. In the current review, we present a general description on recent work regarding different host cells and molecules facilitating antiviral defenses against IAV infection and how IAVs antagonize host immune responses.
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26
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Single-Cell Analysis Uncovers a Vast Diversity in Intracellular Viral Defective Interfering RNA Content Affecting the Large Cell-to-Cell Heterogeneity in Influenza A Virus Replication. Viruses 2020; 12:v12010071. [PMID: 31936115 PMCID: PMC7019491 DOI: 10.3390/v12010071] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/20/2019] [Accepted: 01/03/2020] [Indexed: 12/31/2022] Open
Abstract
Virus replication displays a large cell-to-cell heterogeneity; yet, not all sources of this variability are known. Here, we study the effect of defective interfering (DI) particle (DIP) co-infection on cell-to-cell variability in influenza A virus (IAV) replication. DIPs contain a large internal deletion in one of their eight viral RNAs (vRNA) and are, thus, defective in virus replication. Moreover, they interfere with virus replication. Using single-cell isolation and reverse transcription polymerase chain reaction, we uncovered a large between-cell heterogeneity in the DI vRNA content of infected cells, which was confirmed for DI mRNAs by single-cell RNA sequencing. A high load of intracellular DI vRNAs and DI mRNAs was found in low-productive cells, indicating their contribution to the large cell-to-cell variability in virus release. Furthermore, we show that the magnitude of host cell mRNA expression (some factors may inhibit virus replication), but not the ribosome content, may further affect the strength of single-cell virus replication. Finally, we show that the load of viral mRNAs (facilitating viral protein production) and the DI mRNA content are, independently from one another, connected with single-cell virus production. Together, these insights advance single-cell virology research toward the elucidation of the complex multi-parametric origin of the large cell-to-cell heterogeneity in virus infections.
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27
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Development and Characterization of a Reverse-Genetics System for Influenza D Virus. J Virol 2019; 93:JVI.01186-19. [PMID: 31413133 DOI: 10.1128/jvi.01186-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 08/07/2019] [Indexed: 01/23/2023] Open
Abstract
Influenza D virus (IDV) of the Orthomyxoviridae family has a wide host range and a broad geographical distribution. Recent IDV outbreaks in swine along with serological and genetic evidence of IDV infection in humans have raised concerns regarding the zoonotic potential of this virus. To better study IDV at the molecular level, a reverse-genetics system (RGS) is urgently needed, but to date, no RGS had been described for IDV. In this study, we rescued the recombinant influenza D/swine/Oklahoma/1314/2011 (D/OK) virus by using a bidirectional seven-plasmid-based system and further characterized rescued viruses in terms of growth kinetics, replication stability, and receptor-binding capacity. Our results collectively demonstrated that RGS-derived viruses resembled the parental viruses for these properties, thereby supporting the utility of this RGS to study IDV infection biology. In addition, we developed an IDV minigenome replication assay and identified the E697K mutation in PB1 and the L462F mutation in PB2 that directly affected the activity of the IDV ribonucleoprotein (RNP) complex, resulting in either attenuated or replication-incompetent viruses. Finally, by using the minigenome replication assay, we demonstrated that a single nucleotide polymorphism at position 5 of the 3' conserved noncoding region in IDV and influenza C virus (ICV) resulted in the inefficient cross-recognition of the heterotypic promoter by the viral RNP complex. In conclusion, we successfully developed a minigenome replication assay and a robust reverse-genetics system that can be used to further study replication, tropism, and pathogenesis of IDV.IMPORTANCE Influenza D virus (IDV) is a new type of influenza virus that uses cattle as the primary reservoir and infects multiple agricultural animals. Increased outbreaks in pigs and serological and genetic evidence of human infection have raised concerns about potential IDV adaptation in humans. Here, we have developed a plasmid-based IDV reverse-genetics system that can generate infectious viruses with replication kinetics similar to those of wild-type viruses following transfection of cultured cells. Further characterization demonstrated that viruses rescued from the described RGS resembled the parental viruses in biological and receptor-binding properties. We also developed and validated an IDV minireplicon reporter system that specifically measures viral RNA polymerase activity. In summary, the reverse-genetics system and minireplicon reporter assay described in this study should be of value in identifying viral determinants of cross-species transmission and pathogenicity of novel influenza D viruses.
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28
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Krutikova EV, Stepanova EA, Kiseleva IV, Rudenko LG. Experimental Study of Genetic Constellation of Cold-Adapted Master Donor Viruses for Live Attenuated Influenza Vaccine Type B. Bull Exp Biol Med 2019; 167:384-387. [PMID: 31346883 DOI: 10.1007/s10517-019-04532-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Indexed: 11/26/2022]
Abstract
We studied the constellation of genes encoding polymerase complex proteins of master donor viruses for Russian live attenuated influenza vaccine type B. Reassortants of the reserve attenuation donor B/Leningrad/14/17/55 with B/USSR/60/69 master donor virus currently used for manufacturing seasonal influenza vaccine were prepared and examined. Most reassortants obtained by the classical reassortment method inherited all genes from the B/Leningrad/14/17/55 virus except the gene encoding PB1 subunit of the polymerase complex. One reassortant was selected for further evaluation of the role of PB1 gene. Greater attenuation of the strain for experimental animals (mice) in comparison with the original strains was demonstrated. This indicates high degree of constellation of genes of cold-adapted master donor viruses and the important compensating role of amino acid substitutions in the PB1 protein of B/Leningrad/14/17/55 donor virus in preventing viral hyperattenuation.
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Affiliation(s)
- E V Krutikova
- A. A. Smorodintsev Department of Virology, Institute of Experimental Medicine, St. Petersburg, Russia.
| | - E A Stepanova
- A. A. Smorodintsev Department of Virology, Institute of Experimental Medicine, St. Petersburg, Russia
| | - I V Kiseleva
- A. A. Smorodintsev Department of Virology, Institute of Experimental Medicine, St. Petersburg, Russia
| | - L G Rudenko
- A. A. Smorodintsev Department of Virology, Institute of Experimental Medicine, St. Petersburg, Russia
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Sant AJ, DiPiazza AT, Nayak JL, Rattan A, Richards KA. CD4 T cells in protection from influenza virus: Viral antigen specificity and functional potential. Immunol Rev 2019; 284:91-105. [PMID: 29944766 DOI: 10.1111/imr.12662] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
CD4 T cells convey a number of discrete functions to protective immunity to influenza, a complexity that distinguishes this arm of adaptive immunity from B cells and CD8 T cells. Although the most well recognized function of CD4 T cells is provision of help for antibody production, CD4 T cells are important in many aspects of protective immunity. Our studies have revealed that viral antigen specificity is a key determinant of CD4 T cell function, as illustrated both by mouse models of infection and human vaccine responses, a factor whose importance is due at least in part to events in viral antigen handling. We discuss research that has provided insight into the diverse viral epitope specificity of CD4 T cells elicited after infection, how this primary response is modified as CD4 T cells home to the lung, establish memory, and after challenge with a secondary and distinct influenza virus strain. Our studies in human subjects point out the challenges facing vaccine efforts to facilitate responses to novel and avian strains of influenza, as well as strategies that enhance the ability of CD4 T cells to promote protective antibody responses to both seasonal and potentially pandemic strains of influenza.
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Affiliation(s)
- Andrea J Sant
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Anthony T DiPiazza
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jennifer L Nayak
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA.,Division of Infectious Diseases, Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, USA
| | - Ajitanuj Rattan
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Katherine A Richards
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
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30
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Autophagy Promotes Replication of Influenza A Virus In Vitro. J Virol 2019; 93:JVI.01984-18. [PMID: 30541828 DOI: 10.1128/jvi.01984-18] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 11/27/2018] [Indexed: 12/20/2022] Open
Abstract
Influenza A virus (IAV) infection could induce autophagosome accumulation. However, the impact of the autophagy machinery on IAV infection remains controversial. Here, we showed that induction of cellular autophagy by starvation or rapamycin treatment increases progeny virus production, while disruption of autophagy using a small interfering RNA (siRNA) and pharmacological inhibitor reduces progeny virus production. Further studies revealed that alteration of autophagy significantly affects the early stages of the virus life cycle or viral RNA synthesis. Importantly, we demonstrated that overexpression of both the IAV M2 and NP proteins alone leads to the lipidation of LC3 to LC3-II and a redistribution of LC3 from the cytosol to punctate vesicles indicative of authentic autophagosomes. Intriguingly, both M2 and NP colocalize and interact with LC3 puncta during M2 or NP transfection alone and IAV infection, leading to an increase in viral ribonucleoprotein (vRNP) export and infectious viral particle formation, which indicates that the IAV-host autophagy interaction plays a critical role in regulating IAV replication. We showed that NP and M2 induce the AKT-mTOR-dependent autophagy pathway and an increase in HSP90AA1 expression. Finally, our studies provided evidence that IAV replication needs an autophagy pathway to enhance viral RNA synthesis via the interaction of PB2 and HSP90AA1 by modulating HSP90AA1 expression and the AKT-mTOR signaling pathway in host cells. Collectively, our studies uncover a new mechanism that NP- and M2-mediated autophagy functions in different stages of virus replication in the pathogenicity of influenza A virus.IMPORTANCE Autophagy impacts the replication cycle of many viruses. However, the role of the autophagy machinery in IAV replication remains unclear. Therefore, we explored the detailed mechanisms utilized by IAV to promote its replication. We demonstrated that IAV NP- and M2-mediated autophagy promotes IAV replication by regulating the AKT-mTOR signaling pathway and HSP90AA1 expression. The interaction of PB2 and HSP90AA1 results in the increase of viral RNA synthesis first; subsequently the binding of NP to LC3 favors vRNP export, and later the interaction of M2 and LC3 leads to an increase in the production of infectious viral particles, thus accelerating viral progeny production. These findings improve our understanding of IAV pathogenicity in host cells.
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Asha K, Kumar B. Emerging Influenza D Virus Threat: What We Know so Far! J Clin Med 2019; 8:jcm8020192. [PMID: 30764577 PMCID: PMC6406440 DOI: 10.3390/jcm8020192] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 01/20/2023] Open
Abstract
Influenza viruses, since time immemorial, have been the major respiratory pathogen known to infect a wide variety of animals, birds and reptiles with established lineages. They belong to the family Orthomyxoviridae and cause acute respiratory illness often during local outbreaks or seasonal epidemics and occasionally during pandemics. Recent studies have identified a new genus within the Orthomyxoviridae family. This newly identified pathogen, D/swine/Oklahoma/1334/2011 (D/OK), first identified in pigs with influenza-like illness was classified as the influenza D virus (IDV) which is distantly related to the previously characterized human influenza C virus. Several other back-to-back studies soon suggested cattle as the natural reservoir and possible involvement of IDV in the bovine respiratory disease complex was established. Not much is known about its likelihood to cause disease in humans, but it definitely poses a potential threat as an emerging pathogen in cattle-workers. Here, we review the evolution, epidemiology, virology and pathobiology of influenza D virus and the possibility of transmission among various hosts and potential to cause human disease.
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Affiliation(s)
- Kumari Asha
- Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
| | - Binod Kumar
- Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
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32
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A Mechanism Underlying Attenuation of Recombinant Influenza A Viruses Carrying Reporter Genes. Viruses 2018; 10:v10120679. [PMID: 30513620 PMCID: PMC6316390 DOI: 10.3390/v10120679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/27/2018] [Accepted: 11/27/2018] [Indexed: 12/29/2022] Open
Abstract
Influenza A viruses (IAV) carrying reporter genes provide a powerful tool to study viral infection and pathogenesis in vivo, however, incorporating a non-essential gene into the IAV genome often results in virus attenuation and genetic instability. Very few studies have systematically compared different reporter IAVs, and most optimization attempts seem to lack authentic directions. In this study, we evaluated the ratio of genome copies to the number of infectious unit of two reporter IAVs, PR8-NS1-Gluc and PR8-PB2-Gluc. As a result, PR8-NS1-Gluc and PR8-PB2-Gluc produced 41.4 and 3.8 genomes containing noninfectious particles respectively for every such particle produced by parental PR8 virus. RdRp assay demonstrated that modification of segment NS by inserting reporter genes can interfere with the replication competitive property of the corresponding vRNAs, and the balance of the 8 segments of the reporter IAVs were drastically impaired in infected cells. As a consequence, large amounts of NS-null noninfectious particles were produced during the PR8-NS1-Gluc packaging. In summary, we unravel a mechanism underlying attenuation of reporter IAVs, which suggests a new approach to restore infectivity and virulence by introducing extra mutations compensating for the impaired replication property of corresponding segments.
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The Nucleolar Protein LYAR Facilitates Ribonucleoprotein Assembly of Influenza A Virus. J Virol 2018; 92:JVI.01042-18. [PMID: 30209172 PMCID: PMC6232469 DOI: 10.1128/jvi.01042-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 09/01/2018] [Indexed: 12/13/2022] Open
Abstract
Influenza A viral ribonucleoprotein (vRNP) is responsible for transcription and replication of the viral genome in infected cells and depends on host factors for its functions. Identification of the host factors interacting with vRNP not only improves understanding of virus-host interactions but also provides insights into novel mechanisms of viral pathogenicity and the development of new antiviral strategies. Here, we have identified 80 host factors that copurified with vRNP using affinity purification followed by mass spectrometry. LYAR, a cell growth-regulating nucleolar protein, has been shown to be important for influenza A virus replication. During influenza A virus infection, LYAR expression is increased and partly translocates from the nucleolus to the nucleoplasm and cytoplasm. Furthermore, LYAR interacts with RNP subunits, resulting in enhancing viral RNP assembly, thereby facilitating viral RNA synthesis. Taken together, our studies identify a novel vRNP binding host partner important for influenza A virus replication and further reveal the mechanism of LYAR regulating influenza A viral RNA synthesis by facilitating viral RNP assembly.IMPORTANCE Influenza A virus (IAV) must utilize the host cell machinery to replicate, but many of the mechanisms of IAV-host interaction remain poorly understood. Improved understanding of interactions between host factors and vRNP not only increases our basic knowledge of the molecular mechanisms of virus replication and pathogenicity but also provides insights into possible novel antiviral targets that are necessary due to the widespread emergence of drug-resistant IAV strains. Here, we have identified LYAR, a cell growth-regulating nucleolar protein, which interacts with viral RNP components and is important for efficient replication of IAVs and whose role in the IAV life cycle has never been reported. In addition, we further reveal the role of LYAR in viral RNA synthesis. Our results extend and improve current knowledge on the mechanisms of IAV transcription and replication.
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Klemm C, Boergeling Y, Ludwig S, Ehrhardt C. Immunomodulatory Nonstructural Proteins of Influenza A Viruses. Trends Microbiol 2018; 26:624-636. [PMID: 29373257 DOI: 10.1016/j.tim.2017.12.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 12/07/2017] [Accepted: 12/15/2017] [Indexed: 12/23/2022]
Abstract
Influenza epidemics and pandemics still represent a severe public health threat and cause significant morbidity and mortality worldwide. As intracellular parasites, influenza viruses are strongly dependent on the host cell machinery. To ensure efficient production of progeny viruses, viral proteins extensively interfere with cellular signalling pathways to inhibit antiviral responses or to activate virus-supportive functions. Here, we review various functions of the influenza virus nonstructural proteins NS1, PB1-F2, and PA-X in infected cells and how post-transcriptional modifications of these proteins affect the viral life cycle. Furthermore, we discuss newly discovered interactions between these proteins and the antiviral interferon response.
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Affiliation(s)
- Carolin Klemm
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany
| | - Yvonne Boergeling
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany
| | - Stephan Ludwig
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany
| | - Christina Ehrhardt
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany.
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35
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Ramos-Nascimento A, Kellen B, Ferreira F, Alenquer M, Vale-Costa S, Raposo G, Delevoye C, Amorim MJ. KIF13A mediates trafficking of influenza A virus ribonucleoproteins. J Cell Sci 2017; 130:4038-4050. [PMID: 29061883 DOI: 10.1242/jcs.210807] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/18/2017] [Indexed: 01/18/2023] Open
Abstract
Influenza A is a rapidly evolving virus that is successful in provoking periodic epidemics and occasional pandemics in humans. Viral assembly is complex as the virus incorporates an eight-partite genome of RNA (in the form of viral ribonucleoproteins, vRNPs), and viral genome assembly - with its implications to public health - is not completely understood. It has previously been reported that vRNPs are transported to the cell surface on Rab11-containing vesicles by using microtubules but, so far, no molecular motor has been assigned to the process. Here, we have identified KIF13A, a member of the kinesin-3 family, as the first molecular motor to efficiently transport vRNP-Rab11 vesicles during infection with influenza A. Depletion of KIF13A resulted in reduced viral titers and less accumulation of vRNPs at the cell surface, without interfering with the levels of other viral proteins at sites of viral assembly. In addition, when overexpressed and following two separate approaches to displace vRNP-Rab11 vesicles, KIF13A increased levels of vRNP at the plasma membrane. Together, our results show that KIF13A plays an important role in the transport of influenza A vRNPs, a crucial step for viral assembly.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Ana Ramos-Nascimento
- Cell Biology of Viral Infection Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal.,Institute of Virology, Hannover Medical School, 30625 Hannover, Germany
| | - Bárbara Kellen
- Science4U, MARL Espaços CC02 e CC03, São Julião do Tojal, 2660-421, Loures, Portugal
| | - Filipe Ferreira
- Cell Biology of Viral Infection Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal
| | - Marta Alenquer
- Cell Biology of Viral Infection Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal
| | - Sílvia Vale-Costa
- Cell Biology of Viral Infection Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal
| | - Graça Raposo
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France
| | - Cédric Delevoye
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France
| | - Maria João Amorim
- Cell Biology of Viral Infection Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal
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36
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Su S, Fu X, Li G, Kerlin F, Veit M. Novel Influenza D virus: Epidemiology, pathology, evolution and biological characteristics. Virulence 2017; 8:1580-1591. [PMID: 28812422 DOI: 10.1080/21505594.2017.1365216] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
In 2011, a new virus was isolated from pigs with influenza-like symptoms and subsequently also from cattle, which are the main reservoir of the virus. It is similar to Influenza C virus (ICV), a (predominantly) human pathogen, causing respiratory disease in children. Since the virus is unable to reassort with ICV (and based on several other criteria as discussed in the text) it is now officially named as Influenzavirus D (IDV), a new genus of the Orthomyxoviridae. We summarize the epidemiology, pathology and evolution of IDV and its biological characteristics with emphasis on the only glycoprotein HEF. Based on the limited data available we finally consider whether IDV represent a public health threat.
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Affiliation(s)
- Shuo Su
- a Jiangsu Engineering Laboratory of Animal Immunology , Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China
| | - Xinliang Fu
- b Key Laboratory of Zoonosis Prevention and Control of Guangdong Province and College of Veterinary Medicine , South China Agricultural University , Guangzhou , China
| | - Gairu Li
- a Jiangsu Engineering Laboratory of Animal Immunology , Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China
| | - Fiona Kerlin
- c Institute for Virology, Center for Infection Medicine, Veterinary Faculty , Free University Berlin , Berlin , Germany
| | - Michael Veit
- c Institute for Virology, Center for Infection Medicine, Veterinary Faculty , Free University Berlin , Berlin , Germany
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37
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Chaimayo C, Hayashi T, Underwood A, Hodges E, Takimoto T. Selective incorporation of vRNP into influenza A virions determined by its specific interaction with M1 protein. Virology 2017; 505:23-32. [PMID: 28219018 PMCID: PMC5366082 DOI: 10.1016/j.virol.2017.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 02/09/2017] [Accepted: 02/11/2017] [Indexed: 10/20/2022]
Abstract
Influenza A viruses contain eight single-stranded, negative-sense RNA segments as viral genomes in the form of viral ribonucleoproteins (vRNPs). During genome replication in the nucleus, positive-sense complementary RNPs (cRNPs) are produced as replicative intermediates, which are not incorporated into progeny virions. To analyze the mechanism of selective vRNP incorporation into progeny virions, we quantified vRNPs and cRNPs in the nuclear and cytosolic fractions of infected cells, using a strand-specific qRT-PCR. Unexpectedly, we found that cRNPs were also exported to the cytoplasm. This export was chromosome region maintenance 1 (CRM1)-independent unlike that of vRNPs. Although both vRNPs and cRNPs were present in the cytosol, viral matrix (M1) protein, a key regulator for viral assembly, preferentially bound vRNPs over cRNPs. These results indicate that influenza A viruses selectively uptake cytosolic vRNPs through a specific interaction with M1 during viral assembly.
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Affiliation(s)
- Chutikarn Chaimayo
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States; Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Tsuyoshi Hayashi
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
| | - Andrew Underwood
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
| | - Erin Hodges
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
| | - Toru Takimoto
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States.
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38
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Barman S, Krylov PS, Turner JC, Franks J, Webster RG, Husain M, Webby RJ. Manipulation of neuraminidase packaging signals and hemagglutinin residues improves the growth of A/Anhui/1/2013 (H7N9) influenza vaccine virus yield in eggs. Vaccine 2017; 35:1424-1430. [PMID: 28162820 DOI: 10.1016/j.vaccine.2017.01.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 02/06/2023]
Abstract
In 2013, a novel avian-origin H7N9 influenza A virus causing severe lower respiratory tract disease in humans emerged in China, with continued sporadic cases. An effective vaccine is needed for this virus in case it acquires transmissibility among humans; however, PR8-based A/Anhui/1/2013 (Anhui/1, H7N9), a WHO-recommended H7N9 candidate vaccine virus (CVV) for vaccine production, does not replicate well in chicken eggs, posing an obstacle to egg-based vaccine production. To address this issue, we explored the possibility that PR8's hemagglutinin (HA) and neuraminidase (NA) packaging signals mediate improvement of Anhui/1 CVV yield in eggs. We constructed chimeric HA and NA genes having the coding region of Anhui/1 HA and NA flanked by the 5' and 3' packaging signals of PR8's HA and NA, respectively. The growth of CVVs containing the chimeric HA was not affected, but that of those containing the chimeric NA gene grew in embryonated chicken eggs with a more than 2-fold higher titer than that of WT CVV. Upon 6 passages in eggs further yield increase was achieved although this was not associated with any changes in the chimeric NA gene. The HA of the passaged CVV, did, however, exhibit egg-adaptive mutations and one of them (HA-G218E) improved CVV growth in eggs without significantly changing antigenicity. The HA-G218E substitution and a chimeric NA, thus, combine to provide an Anhui/1 CVV with properties more favorable for vaccine manufacture.
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Affiliation(s)
- Subrata Barman
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Petr S Krylov
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Jasmine C Turner
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - John Franks
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Robert G Webster
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Matloob Husain
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
| | - Richard J Webby
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA.
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39
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Abstract
Segmented RNA viruses are widespread in nature and include important human, animal and plant pathogens, such as influenza viruses and rotaviruses. Although the origin of RNA virus genome segmentation remains elusive, a major consequence of this genome structure is the capacity for reassortment to occur during co-infection, whereby segments are exchanged among different viral strains. Therefore, reassortment can create viral progeny that contain genes that are derived from more than one parent, potentially conferring important fitness advantages or disadvantages to the progeny virus. However, for segmented RNA viruses that package their multiple genome segments into a single virion particle, reassortment also requires genetic compatibility between parental strains, which occurs in the form of conserved packaging signals, and the maintenance of RNA and protein interactions. In this Review, we discuss recent studies that examined the mechanisms and outcomes of reassortment for three well-studied viral families - Cystoviridae, Orthomyxoviridae and Reoviridae - and discuss how these findings provide new perspectives on the replication and evolution of segmented RNA viruses.
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40
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Nogales A, Baker SF, Domm W, Martínez-Sobrido L. Development and applications of single-cycle infectious influenza A virus (sciIAV). Virus Res 2016; 216:26-40. [PMID: 26220478 PMCID: PMC4728073 DOI: 10.1016/j.virusres.2015.07.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 07/05/2015] [Accepted: 07/13/2015] [Indexed: 02/06/2023]
Abstract
The diverse host range, high transmissibility, and rapid evolution of influenza A viruses justify the importance of containing pathogenic viruses studied in the laboratory. Other than physically or mechanically changing influenza A virus containment procedures, modifying the virus to only replicate for a single round of infection similarly ensures safety and consequently decreases the level of biosafety containment required to study highly pathogenic members in the virus family. This biological containment is more ideal because it is less apt to computer, machine, or human error. With many necessary proteins that can be deleted, generation of single-cycle infectious influenza A viruses (sciIAV) can be achieved using a variety of approaches. Here, we review the recent burst in sciIAV generation and summarize the applications and findings on this important human pathogen using biocontained viral mimics.
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Affiliation(s)
- Aitor Nogales
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Steven F Baker
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - William Domm
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Luis Martínez-Sobrido
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States.
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41
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Peng X, Wu H, Peng X, Wu X, Cheng L, Liu F, Ji S, Wu N. Amino acid substitutions occurring during adaptation of an emergent H5N6 avian influenza virus to mammals. Arch Virol 2016; 161:1665-70. [PMID: 26997612 DOI: 10.1007/s00705-016-2826-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 03/13/2016] [Indexed: 12/15/2022]
Abstract
Avian influenza viruses (AIVs) are known to cross species barriers, and emergent highly pathogenic H5N6 AIVs pose a serious threat to human health and the poultry industry. Here, we serially passaged an H5N6 virus 10 times in BALB/c mice. The pathogenicity of the wild-type 6D2 (WT-6D2) and mammal-adapted 6D2 strain (MA-6D2) were compared. The viral titer in multiple organs and the death rate for MA-6D2 were significantly higher than for WT-6D2. We provide evidence that the mutations HA A150V, NA R143K and G147E, PB2 E627K, and PA A343T may be important for adaptation of H5N6 AIVs to mammals.
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Affiliation(s)
- Xiuming Peng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Haibo Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Xiaorong Peng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Xiaoxin Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Linfang Cheng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Fumin Liu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Shujing Ji
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Nanping Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China.
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42
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Avilov S, Magnus J, Cusack S, Naffakh N. Time-Resolved Visualisation of Nearly-Native Influenza A Virus Progeny Ribonucleoproteins and Their Individual Components in Live Infected Cells. PLoS One 2016; 11:e0149986. [PMID: 26978069 PMCID: PMC4792379 DOI: 10.1371/journal.pone.0149986] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 02/06/2016] [Indexed: 02/02/2023] Open
Abstract
Influenza viruses are a global health concern because of the permanent threat of novel emerging strains potentially capable of causing pandemics. Viral ribonucleoproteins (vRNPs) containing genomic RNA segments, nucleoprotein oligomers, and the viral polymerase, play a central role in the viral replication cycle. Our knowledge about critical events such as vRNP assembly and interactions with other viral and cellular proteins is poor and could be substantially improved by time lapse imaging of the infected cells. However, such studies are limited by the difficulty to achieve live-cell compatible labeling of active vRNPs. Previously we designed the first unimpaired recombinant influenza WSN-PB2-GFP11 virus allowing fluorescent labeling of the PB2 subunit of the viral polymerase (Avilov et al., J.Virol. 2012). Here, we simultaneously labeled the viral PB2 protein using the above-mentioned strategy, and virus-encoded progeny RNPs through spontaneous incorporation of transiently expressed NP-mCherry fusion proteins during RNP assembly in live infected cells. This dual labeling enabled us to visualize progeny vRNPs throughout the infection cycle and to characterize independently the mobility, oligomerization status and interactions of vRNP components in the nuclei of live infected cells.
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Affiliation(s)
- Sergiy Avilov
- European Molecular Biology Laboratory, Grenoble Outstation, Grenoble, France
- University Grenoble Alpes-CNRS-EMBL International Unit (UMI 3265) for Virus Host-Cell Interactions, UMI 3265, Grenoble, France
- * E-mail: (NN); (SA)
| | - Julie Magnus
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Département de Virologie, Paris, France
- CNRS, UMR 3569, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Génétique Moléculaire des Virus à ARN, Paris, France
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation, Grenoble, France
- University Grenoble Alpes-CNRS-EMBL International Unit (UMI 3265) for Virus Host-Cell Interactions, UMI 3265, Grenoble, France
| | - Nadia Naffakh
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Département de Virologie, Paris, France
- CNRS, UMR 3569, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Génétique Moléculaire des Virus à ARN, Paris, France
- * E-mail: (NN); (SA)
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Liu CL, Hung HC, Lo SC, Chiang CH, Chen IJ, Hsu JTA, Hou MH. Using mutagenesis to explore conserved residues in the RNA-binding groove of influenza A virus nucleoprotein for antiviral drug development. Sci Rep 2016; 6:21662. [PMID: 26916998 PMCID: PMC4768256 DOI: 10.1038/srep21662] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 01/14/2016] [Indexed: 11/09/2022] Open
Abstract
Nucleoprotein (NP) is the most abundant type of RNA-binding viral protein in influenza A virus-infected cells and is necessary for viral RNA transcription and replication. Recent studies demonstrated that influenza NP is a valid target for antiviral drug development. The surface of the groove, covered with numerous conserved residues between the head and body domains of influenza A NP, plays a crucial role in RNA binding. To explore the mechanism by which NP binds RNA, we performed a series of site-directed mutagenesis in the RNA-binding groove, followed by surface plasmon resonance (SPR), to characterize the interactions between RNA and NP. Furthermore, a role of Y148 in NP stability and NP-RNA binding was evaluated. The aromatic residue of Y148 was found to stack with a nucleotide base. By interrupting the stacking interaction between Y148 and an RNA base, we identified an influenza virus NP inhibitor, (E, E)-1,7-bis(4-hydroxy-3-methoxyphenyl) -1,6-heptadiene-3,5-dione; this inhibitor reduced the NP's RNA-binding affinity and hindered viral replication. Our findings will be useful for the development of new drugs that disrupt the interaction between RNA and viral NP in the influenza virus.
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Affiliation(s)
- Chia-Lin Liu
- National Chung Hsing University, Department of Life Science, Taichung, 40227, Taiwan
| | - Hui-Chen Hung
- National Health Research Institutes, Institute of Biotechnology and Pharmaceutical Research, Miaoli, 35053, Taiwan
| | - Shou-Chen Lo
- National Chung Hsing University, Institute of Genomics and Bioinformatics, Taichung, 40227, Taiwan
| | - Ching-Hui Chiang
- National Chung Hsing University, Department of Life Science, Taichung, 40227, Taiwan
| | - I-Jung Chen
- National Health Research Institutes, Institute of Biotechnology and Pharmaceutical Research, Miaoli, 35053, Taiwan
| | - John T-A Hsu
- National Health Research Institutes, Institute of Biotechnology and Pharmaceutical Research, Miaoli, 35053, Taiwan
| | - Ming-Hon Hou
- National Chung Hsing University, Department of Life Science, Taichung, 40227, Taiwan.,National Chung Hsing University, Institute of Genomics and Bioinformatics, Taichung, 40227, Taiwan.,National Chung Hsing University, Institute of Biotechnology, Taichung, 40227, Taiwan
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Mäkelä SM, Österlund P, Westenius V, Latvala S, Diamond MS, Gale M, Julkunen I. RIG-I Signaling Is Essential for Influenza B Virus-Induced Rapid Interferon Gene Expression. J Virol 2015; 89:12014-25. [PMID: 26378160 PMCID: PMC4645339 DOI: 10.1128/jvi.01576-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/13/2015] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Influenza B virus causes annual epidemics and, along with influenza A virus, accounts for substantial disease and economic burden throughout the world. Influenza B virus infects only humans and some marine mammals and is not responsible for pandemics, possibly due to a very low frequency of reassortment and a lower evolutionary rate than that of influenza A virus. Influenza B virus has been less studied than influenza A virus, and thus, a comparison of influenza A and B virus infection mechanisms may provide new insight into virus-host interactions. Here we analyzed the early events in influenza B virus infection and interferon (IFN) gene expression in human monocyte-derived macrophages and dendritic cells. We show that influenza B virus induces IFN regulatory factor 3 (IRF3) activation and IFN-λ1 gene expression with faster kinetics than does influenza A virus, without a requirement for viral protein synthesis or replication. Influenza B virus-induced activation of IRF3 required the fusion of viral and endosomal membranes, and nuclear accumulation of IRF3 and viral NP occurred concurrently. In comparison, immediate early IRF3 activation was not observed in influenza A virus-infected macrophages. Experiments with RIG-I-, MDA5-, and RIG-I/MDA5-deficient mouse fibroblasts showed that RIG-I is the critical pattern recognition receptor needed for the influenza B virus-induced activation of IRF3. Our results show that innate immune mechanisms are activated immediately after influenza B virus entry through the endocytic pathway, whereas influenza A virus avoids early IRF3 activation and IFN gene induction. IMPORTANCE Recently, a great deal of interest has been paid to identifying the ligands for RIG-I under conditions of natural infection, as many previous studies have been based on transfection of cells with different types of viral or synthetic RNA structures. We shed light on this question by analyzing the earliest step in innate immune recognition of influenza B virus by human macrophages. We show that influenza B virus induces IRF3 activation, leading to IFN gene expression after viral RNPs (vRNPs) are released into the cytosol and are recognized by RIG-I receptor, meaning that the incoming influenza B virus is already able to activate IFN gene expression. In contrast, influenza A (H3N2) virus failed to activate IRF3 at very early times of infection, suggesting that there are differences in innate immune recognition between influenza A and B viruses.
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Affiliation(s)
- Sanna M Mäkelä
- Viral Infections Unit, Department of Infectious Diseases, National Institute for Health and Welfare, Helsinki, Finland
| | - Pamela Österlund
- Viral Infections Unit, Department of Infectious Diseases, National Institute for Health and Welfare, Helsinki, Finland
| | - Veera Westenius
- Viral Infections Unit, Department of Infectious Diseases, National Institute for Health and Welfare, Helsinki, Finland
| | - Sinikka Latvala
- Viral Infections Unit, Department of Infectious Diseases, National Institute for Health and Welfare, Helsinki, Finland
| | - Michael S Diamond
- Departments of Medicine, Pathology and Immunology, and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael Gale
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Ilkka Julkunen
- Viral Infections Unit, Department of Infectious Diseases, National Institute for Health and Welfare, Helsinki, Finland Department of Virology, University of Turku, Turku, Finland
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Fragile X mental retardation protein stimulates ribonucleoprotein assembly of influenza A virus. Nat Commun 2015; 5:3259. [PMID: 24514761 DOI: 10.1038/ncomms4259] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 01/15/2014] [Indexed: 12/16/2022] Open
Abstract
The ribonucleoprotein (RNP) of the influenza A virus is responsible for the transcription and replication of viral RNA in the nucleus. These processes require interplay between host factors and RNP components. Here, we report that the Fragile X mental retardation protein (FMRP) targets influenza virus RNA synthesis machinery and facilitates virus replication both in cell culture and in mice. We demonstrate that FMRP transiently associates with viral RNP and stimulates viral RNP assembly through RNA-mediated interaction with the nucleoprotein. Furthermore, the KH2 domain of FMRP mediates its association with the nucleoprotein. A point mutation (I304N) in the KH2 domain, identified from a Fragile X syndrome patient, disrupts the FMRP-nucleoprotein association and abolishes the ability of FMRP to participate in viral RNP assembly. We conclude that FMRP is a critical host factor used by influenza viruses to facilitate viral RNP assembly. Our observation reveals a mechanism of influenza virus RNA synthesis and provides insights into FMRP functions.
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Dimmock NJ, Easton AJ. Cloned Defective Interfering Influenza RNA and a Possible Pan-Specific Treatment of Respiratory Virus Diseases. Viruses 2015; 7:3768-88. [PMID: 26184282 PMCID: PMC4517125 DOI: 10.3390/v7072796] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 06/27/2015] [Accepted: 07/03/2015] [Indexed: 12/24/2022] Open
Abstract
Defective interfering (DI) genomes are characterised by their ability to interfere with the replication of the virus from which they were derived, and other genetically compatible viruses. DI genomes are synthesized by nearly all known viruses and represent a vast natural reservoir of antivirals that can potentially be exploited for use in the clinic. This review describes the application of DI virus to protect from virus-associated diseases in vivo using as an example a highly active cloned influenza A DI genome and virus that protects broadly in preclinical trials against different subtypes of influenza A and against non-influenza A respiratory viruses. This influenza A-derived DI genome protects by two totally different mechanisms: molecular interference with influenza A replication and by stimulating innate immunity that acts against non-influenza A viruses. The review considers what is needed to develop DI genomes to the point of entry into clinical trials.
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Affiliation(s)
- Nigel J Dimmock
- School of Life Sciences, University of Warwick, Coventry CV4-7AL, UK.
| | - Andrew J Easton
- School of Life Sciences, University of Warwick, Coventry CV4-7AL, UK.
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Kamal RP, Katz JM, York IA. Molecular determinants of influenza virus pathogenesis in mice. Curr Top Microbiol Immunol 2015; 385:243-74. [PMID: 25038937 DOI: 10.1007/82_2014_388] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mice are widely used for studying influenza virus pathogenesis and immunology because of their low cost, the wide availability of mouse-specific reagents, and the large number of mouse strains available, including knockout and transgenic strains. However, mice do not fully recapitulate the signs of influenza infection of humans: transmission of influenza between mice is much less efficient than in humans, and influenza viruses often require adaptation before they are able to efficiently replicate in mice. In the process of mouse adaptation, influenza viruses acquire mutations that enhance their ability to attach to mouse cells, replicate within the cells, and suppress immunity, among other functions. Many such mouse-adaptive mutations have been identified, covering all 8 genomic segments of the virus. Identification and analysis of these mutations have provided insight into the molecular determinants of influenza virulence and pathogenesis, not only in mice but also in humans and other species. In particular, several mouse-adaptive mutations of avian influenza viruses have proved to be general mammalian-adaptive changes that are potential markers of pre-pandemic viruses. As well as evaluating influenza pathogenesis, mice have also been used as models for evaluation of novel vaccines and anti-viral therapies. Mice can be a useful animal model for studying influenza biology as long as differences between human and mice infections are taken into account.
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Affiliation(s)
- Ram P Kamal
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, USA,
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The avian-origin PB1 gene segment facilitated replication and transmissibility of the H3N2/1968 pandemic influenza virus. J Virol 2015; 89:4170-9. [PMID: 25631088 DOI: 10.1128/jvi.03194-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The H2N2/1957 and H3N2/1968 pandemic influenza viruses emerged via the exchange of genomic RNA segments between human and avian viruses. The avian hemagglutinin (HA) allowed the hybrid viruses to escape preexisting immunity in the human population. Both pandemic viruses further received the PB1 gene segment from the avian parent (Y. Kawaoka, S. Krauss, and R. G. Webster, J Virol 63:4603-4608, 1989), but the biological significance of this observation was not understood. To assess whether the avian-origin PB1 segment provided pandemic viruses with some selective advantage, either on its own or via cooperation with the homologous HA segment, we modeled by reverse genetics the reassortment event that led to the emergence of the H3N2/1968 pandemic virus. Using seasonal H2N2 virus A/California/1/66 (Cal) as a surrogate precursor human virus and pandemic virus A/Hong Kong/1/68 (H3N2) (HK) as a source of avian-derived PB1 and HA gene segments, we generated four reassortant recombinant viruses and compared pairs of viruses which differed solely by the origin of PB1. Replacement of the PB1 segment of Cal by PB1 of HK facilitated viral polymerase activity, replication efficiency in human cells, and contact transmission in guinea pigs. A combination of PB1 and HA segments of HK did not enhance replicative fitness of the reassortant virus compared with the single-gene PB1 reassortant. Our data suggest that the avian PB1 segment of the 1968 pandemic virus served to enhance viral growth and transmissibility, likely by enhancing activity of the viral polymerase complex. IMPORTANCE Despite the high impact of influenza pandemics on human health, some mechanisms underlying the emergence of pandemic influenza viruses still are poorly understood. Thus, it was unclear why both H2N2/1957 and H3N2/1968 reassortant pandemic viruses contained, in addition to the avian HA, the PB1 gene segment of the avian parent. Here, we addressed this long-standing question by modeling the emergence of the H3N2/1968 virus from its putative human and avian precursors. We show that the avian PB1 segment increased activity of the viral polymerase and facilitated viral replication. Our results suggest that in addition to the acquisition of antigenically novel HA (i.e., antigenic shift), enhanced viral polymerase activity is required for the emergence of pandemic influenza viruses from their seasonal human precursors.
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Abstract
The Orthomyxoviridae is a family of viruses that possess segmented, single-stranded, and negative-sense RNA genome. It contains influenza A virus, which is one of the most important pathogens to our public health. Here, I review general properties of Orthomyxoviruses with a focus on influenza viruses.
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Defective interfering influenza virus RNAs: time to reevaluate their clinical potential as broad-spectrum antivirals? J Virol 2014; 88:5217-27. [PMID: 24574404 DOI: 10.1128/jvi.03193-13] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Defective interfering (DI) RNAs are highly deleted forms of the infectious genome that are made by most families of RNA viruses. DI RNAs retain replication and packaging signals, are synthesized preferentially over infectious genomes, and are packaged as DI virus particles which can be transmitted to susceptible cells. Their ability to interfere with the replication of infectious virus in cell culture and their potential as antivirals in the clinic have long been known. However, until now, no realistic formulation has been described. In this review, we consider the early evidence of antiviral activity by DI viruses and, using the example of DI influenza A virus, outline developments that have led to the production of a cloned DI RNA that is highly active in preclinical studies not only against different subtypes of influenza A virus but also against heterologous respiratory viruses. These data suggest the timeliness of reassessing the potential of DI viruses as a novel class of antivirals that may have general applicability.
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