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Donátová K, Mladá M, Lopušná K, Baran F, Betáková T. Changes in the Expression of Proteins Associated with Neurodegeneration in the Brains of Mice after Infection with Influenza A Virus with Wild Type and Truncated NS1. Int J Mol Sci 2024; 25:2460. [PMID: 38473707 DOI: 10.3390/ijms25052460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 03/14/2024] Open
Abstract
Influenza type A virus (IAV) infection is a major cause of morbidity and mortality during influenza epidemics. Recently, a specific link between IAV infection and neurodegenerative disease progression has been established. The non-structural NS1 protein of IAV regulates viral replication during infection and antagonizes host antiviral responses, contributing to influenza virulence. In the present study, we have prepared a mouse lung-to-lung adapted to the NS1-truncated virus (NS80ad). Transcriptome analysis of the gene expression in the lungs revealed that infection with wild-type A/WSN/33 (WSN), NS80, and NS80ad viruses resulted in different regulation of genes involved in signaling pathways associated with the cell proliferation, inflammatory response, and development of neurodegenerative diseases. NS1 protein did not influence the genes involved in the RIG-I-like receptor signaling pathway in the brains. Lethal infection with IAVs dysregulated expression of proteins associated with the development of neurodegenerative diseases (CX3CL1/Fractalkine, Coagulation factor III, and CD105/Endoglin, CD54/ICAM-1, insulin-like growth factor-binding protein (IGFBP)-2, IGFBP-5, IGFBP-6, chitinase 3-like 1 (CHI3L1), Myeloperoxidase (MPO), Osteopontin (OPN), cystatin C, and LDL R). Transcription of GATA3 mRNA was decreased, and expression of MPO was inhibited in the brain infected with NS80 and NS80ad viruses. In addition, the truncation of NS1 protein led to reduced expression of IGFBP-2, CHI3L1, MPO, and LDL-R proteins in the brains. Our results indicate that the influenza virus influences the expression of proteins involved in brain function, and this might occur mostly through the NS1 protein. These findings suggest that the abovementioned proteins represent a promising target for the development of potentially effective immunotherapy against neurodegeneration.
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Affiliation(s)
- Karin Donátová
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia
| | - Miriam Mladá
- Biomedical Research Center, Institute of Virology, Slovak Academy of Sciences, 845 05 Bratislava, Slovakia
| | - Katarína Lopušná
- Biomedical Research Center, Institute of Virology, Slovak Academy of Sciences, 845 05 Bratislava, Slovakia
| | - Filip Baran
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia
| | - Tatiana Betáková
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia
- Biomedical Research Center, Institute of Virology, Slovak Academy of Sciences, 845 05 Bratislava, Slovakia
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2
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Hancková M, Miháliková L, Pastoreková S, Betáková T. Hypoxia alters the immune response in mouse peritoneal macrophages infected with influenza a virus with truncated NS1 protein. Cytokine 2023; 164:156138. [PMID: 36796258 DOI: 10.1016/j.cyto.2023.156138] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/30/2022] [Accepted: 01/19/2023] [Indexed: 02/16/2023]
Abstract
Macrophages are the most abundant cells in infected tissue and are involved in the clearing infection, and immunomodulation of the innate and adaptive immune response. NS80 virus of influenza A virus, which encodes only the first 80 aa of the NS1 protein, suppresses the immune host response and is associated with enhanced pathogenicity. Hypoxia promotes infiltration of peritoneal macrophages into the adipose tissue and production of cytokines. To understand the role of hypoxia in the regulation of immune response, macrophages were infected with A/WSN/33 (WSN) and NS80 virus, and transcriptional profiles of the RIG-I-like receptor signalling pathway and expression of cytokines were evaluated in normoxia and hypoxia. Hypoxia inhibited the proliferation of IC-21 cells, downregulated the RIG-I-like receptor signalling pathway, and inhibited transcriptional activity of IFN-α, IFN-β, IFN-ε, and IFN-λ mRNA in infected macrophages. While transcription of IL-1β and Casp-1 mRNAs were increased in infected macrophages in normoxia, hypoxia resulted in decreased transcription activity of IL-1β and Casp-1 mRNAs. Hypoxia significantly affected expression of the translation factors IRF4, IFN-γ, and CXCL10 involved in regulation of immune response and polarization of the macrophages. The expression of pro-inflammatory cytokines such as sICAM-1, IL-1α, TNF-α, CCL2, CCL3, CXCL12, and M-CSF was to a large extent affected in uninfected and infected macrophages cultivated in hypoxia. The NS80 virus increased the expression of M-CSF, IL-16, CCL2, CCL3, and CXCL12, especially under hypoxia. The results show that hypoxia may play an important role in peritoneal macrophage activation, regulates the innate and adaptive immune response, changes production of pro-inflammatory cytokines, promotes macrophage polarization, and could affect the function of other immune cells.
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Affiliation(s)
- Miriam Hancková
- Biomedical Research Center, Slovak Academy of Sciences, Institute of Virology, Bratislava, Slovak Republic
| | - Lucia Miháliková
- Biomedical Research Center, Slovak Academy of Sciences, Institute of Virology, Bratislava, Slovak Republic
| | - Silvia Pastoreková
- Biomedical Research Center, Slovak Academy of Sciences, Institute of Virology, Bratislava, Slovak Republic
| | - Tatiana Betáková
- Biomedical Research Center, Slovak Academy of Sciences, Institute of Virology, Bratislava, Slovak Republic; Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Bratislava, Slovak Republic.
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3
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Naceri S, Marc D, Camproux AC, Flatters D. Influenza A Virus NS1 Protein Structural Flexibility Analysis According to Its Structural Polymorphism Using Computational Approaches. Int J Mol Sci 2022; 23:ijms23031805. [PMID: 35163728 PMCID: PMC8836794 DOI: 10.3390/ijms23031805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 01/27/2023] Open
Abstract
Influenza A viruses are highly contagious RNA viruses that cause respiratory tract infections in humans and animals. Their non-structural protein NS1, a homodimer of two 230-residue chains, is the main viral factor in counteracting the antiviral defenses of the host cell. Its RNA-binding domain is an obligate dimer that is connected to each of the two effector domains by a highly flexible unstructured linker region of ten amino acids. The flexibility of NS1 is a key property that allows its effector domains and its RNA binding domain to interact with several protein partners or RNAs. The three-dimensional structures of full-length NS1 dimers revealed that the effector domains could adopt three distinct conformations as regards their mutual interactions and their orientation relative to the RNA binding domain (closed, semi-open and open). The origin of this structural polymorphism is currently being investigated and several hypotheses are proposed, among which one posits that it is a strain-specific property. In the present study, we explored through computational molecular modeling the dynamic and flexibility properties of NS1 from three important influenza virus A strains belonging to three distinct subtypes (H1N1, H6N6, H5N1), for which at least one conformation is available in the Protein Data Bank. In order to verify whether NS1 is stable in three forms for the three strains, we constructed homology models if the corresponding forms were not available in the Protein Data Bank. Molecular dynamics simulations were performed in order to predict the stability over time of the three distinct sequence variants of NS1, in each of their three distinct conformations. Our results favor the co-existence of three stable structural forms, regardless of the strain, but also suggest that the length of the linker, along with the presence of specific amino acids, modulate the dynamic properties and the flexibility of NS1.
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Affiliation(s)
- Sarah Naceri
- Université de Paris, CNRS, INSERM, Unité de Biologie Fonctionnelle et Adaptative, 75013 Paris, France; (S.N.); (A.-C.C.)
| | - Daniel Marc
- Equipe 3IMo, UMR1282 Infectiologie et Santé Publique, INRAE, 37380 Nouzilly, France;
- UMR1282, Infectiologie et Santé Publique, Université de Tours, 37000 Tours, France
| | - Anne-Claude Camproux
- Université de Paris, CNRS, INSERM, Unité de Biologie Fonctionnelle et Adaptative, 75013 Paris, France; (S.N.); (A.-C.C.)
| | - Delphine Flatters
- Université de Paris, CNRS, INSERM, Unité de Biologie Fonctionnelle et Adaptative, 75013 Paris, France; (S.N.); (A.-C.C.)
- Correspondence:
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4
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Mettier J, Marc D, Sedano L, Da Costa B, Chevalier C, Le Goffic R. Study of the host specificity of PB1-F2-associated virulence. Virulence 2021; 12:1647-1660. [PMID: 34125653 PMCID: PMC8205076 DOI: 10.1080/21505594.2021.1933848] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Influenza A viruses cause important diseases in both human and animal. The PB1-F2 protein is a virulence factor expressed by some influenza viruses. Its deleterious action for the infected host is mostly described in mammals, while the available information is scarce in avian hosts. In this work, we compared the effects of PB1-F2 in avian and mammalian hosts by taking advantage of the zoonotic capabilities of an avian H7N1 virus. In vitro, the H7N1 virus did not behave differently when PB1-F2 was deficient while a H3N2 virus devoid of PB1-F2 was clearly less inflammatory. Likewise, when performing in vivo challenges of either chickens or embryonated eggs, with the wild-type or the PB1-F2 deficient virus, no difference could be observed in terms of mortality, host response or tropism. PB1-F2 therefore does not appear to play a major role as a virulence factor in the avian host. However, when infecting NF-κB-luciferase reporter mice with the H7N1 viruses, a massive PB1-F2-dependent inflammation was quantified, highlighting the host specificity of PB1-F2 virulence. Surprisingly, a chimeric 7:1 H3N2 virus harboring an H7N1-origin segment 2 (i.e. expressing the avian PB1-F2) induced a milder inflammatory response than its PB1-F2-deficient counterpart. This result shows that the pro-inflammatory activity of PB1-F2 is governed by complex mechanisms involving components from both the virus and its infected host. Thus, a mere exchange of segment 2 between strains is not sufficient to transmit the deleterious character of PB1-F2.
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Affiliation(s)
- Joëlle Mettier
- Université Paris-Saclay, INRAE, UVSQ, UMR892 VIM, Jouy-en-Josas, France
| | - Daniel Marc
- UMR1282 Infectiologie Et Santé Publique, INRAE, Nouzilly, France
| | - Laura Sedano
- Université Paris-Saclay, INRAE, UVSQ, UMR892 VIM, Jouy-en-Josas, France
| | - Bruno Da Costa
- Université Paris-Saclay, INRAE, UVSQ, UMR892 VIM, Jouy-en-Josas, France
| | | | - Ronan Le Goffic
- Université Paris-Saclay, INRAE, UVSQ, UMR892 VIM, Jouy-en-Josas, France
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Wacquiez A, Coste F, Kut E, Gaudon V, Trapp S, Castaing B, Marc D. Structure and Sequence Determinants Governing the Interactions of RNAs with Influenza A Virus Non-Structural Protein NS1. Viruses 2020; 12:E947. [PMID: 32867106 PMCID: PMC7552008 DOI: 10.3390/v12090947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/17/2020] [Accepted: 08/25/2020] [Indexed: 11/16/2022] Open
Abstract
The non-structural protein NS1 of influenza A viruses is an RNA-binding protein of which its activities in the infected cell contribute to the success of the viral cycle, notably through interferon antagonism. We have previously shown that NS1 strongly binds RNA aptamers harbouring virus-specific sequence motifs (Marc et al., Nucleic Acids Res. 41, 434-449). Here, we started out investigating the putative role of one particular virus-specific motif through the phenotypic characterization of mutant viruses that were genetically engineered from the parental strain WSN. Unexpectedly, our data did not evidence biological importance of the putative binding of NS1 to this specific motif (UGAUUGAAG) in the 3'-untranslated region of its own mRNA. Next, we sought to identify specificity determinants in the NS1-RNA interaction through interaction assays in vitro with several RNA ligands and through solving by X-ray diffraction the 3D structure of several complexes associating NS1's RBD with RNAs of various affinities. Our data show that the RBD binds the GUAAC motif within double-stranded RNA helices with an apparent specificity that may rely on the sequence-encoded ability of the RNA to bend its axis. On the other hand, we showed that the RBD binds to the virus-specific AGCAAAAG motif when it is exposed in the apical loop of a high-affinity RNA aptamer, probably through a distinct mode of interaction that still requires structural characterization. Our data are consistent with more than one mode of interaction of NS1's RBD with RNAs, recognizing both structure and sequence determinants.
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MESH Headings
- 3' Untranslated Regions
- Animals
- Aptamers, Nucleotide/chemistry
- Aptamers, Nucleotide/metabolism
- Base Sequence
- Cell Line
- Humans
- Influenza A Virus, H1N1 Subtype/chemistry
- Influenza A Virus, H7N1 Subtype/chemistry
- Models, Molecular
- Nucleic Acid Conformation
- Protein Binding
- Protein Domains
- RNA/chemistry
- RNA/metabolism
- RNA, Double-Stranded/chemistry
- RNA, Double-Stranded/metabolism
- RNA, Messenger/chemistry
- RNA, Messenger/metabolism
- RNA, Viral/chemistry
- RNA, Viral/metabolism
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/metabolism
- SELEX Aptamer Technique
- Viral Nonstructural Proteins/chemistry
- Viral Nonstructural Proteins/metabolism
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Affiliation(s)
- Alan Wacquiez
- Equipe 3IMo, UMR1282 Infectiologie et Santé Publique, INRAE, F-37380 Nouzilly, France; (A.W.); (E.K.); (S.T.)
- UMR1282 Infectiologie et Santé Publique, Université de Tours, F-37000 Tours, France
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 02, 45071 Orléans, France; (F.C.); (V.G.)
| | - Franck Coste
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 02, 45071 Orléans, France; (F.C.); (V.G.)
| | - Emmanuel Kut
- Equipe 3IMo, UMR1282 Infectiologie et Santé Publique, INRAE, F-37380 Nouzilly, France; (A.W.); (E.K.); (S.T.)
- UMR1282 Infectiologie et Santé Publique, Université de Tours, F-37000 Tours, France
| | - Virginie Gaudon
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 02, 45071 Orléans, France; (F.C.); (V.G.)
| | - Sascha Trapp
- Equipe 3IMo, UMR1282 Infectiologie et Santé Publique, INRAE, F-37380 Nouzilly, France; (A.W.); (E.K.); (S.T.)
- UMR1282 Infectiologie et Santé Publique, Université de Tours, F-37000 Tours, France
| | - Bertrand Castaing
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 02, 45071 Orléans, France; (F.C.); (V.G.)
| | - Daniel Marc
- Equipe 3IMo, UMR1282 Infectiologie et Santé Publique, INRAE, F-37380 Nouzilly, France; (A.W.); (E.K.); (S.T.)
- UMR1282 Infectiologie et Santé Publique, Université de Tours, F-37000 Tours, France
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6
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Molecular Dynamics Simulations of Influenza A Virus NS1 Reveal a Remarkably Stable RNA-Binding Domain Harboring Promising Druggable Pockets. Viruses 2020; 12:v12050537. [PMID: 32422922 PMCID: PMC7290946 DOI: 10.3390/v12050537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/05/2020] [Accepted: 05/12/2020] [Indexed: 12/11/2022] Open
Abstract
The non-structural protein NS1 of influenza A viruses is considered to be the major antagonist of the interferon system and antiviral defenses of the cell. It could therefore represent a suitable target for novel antiviral strategies. As a first step towards the identification of small compounds targeting NS1, we here investigated the druggable potential of its RNA-binding domain since this domain is essential to the biological activities of NS1. We explored the flexibility of the full-length protein by running molecular dynamics simulations on one of its published crystal structures. While the RNA-binding domain structure was remarkably stable along the simulations, we identified a flexible site at the two extremities of the “groove” that is delimited by the antiparallel α-helices that make up its RNA-binding interface. This groove region is able to form potential binding pockets, which, in 60% of the conformations, meet the druggability criteria. We characterized these pockets and identified the residues that contribute to their druggability. All the residues involved in the druggable pockets are essential at the same time to the stability of the RNA-binding domain and to the biological activities of NS1. They are also strictly conserved across the large sequence diversity of NS1, emphasizing the robustness of this search towards the identification of broadly active NS1-targeting compounds.
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7
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Bryson KJ, Garrido D, Esposito M, McLachlan G, Digard P, Schouler C, Guabiraba R, Trapp S, Vervelde L. Precision cut lung slices: a novel versatile tool to examine host-pathogen interaction in the chicken lung. Vet Res 2020; 51:2. [PMID: 31924278 PMCID: PMC6954617 DOI: 10.1186/s13567-019-0733-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 12/12/2019] [Indexed: 01/12/2023] Open
Abstract
The avian respiratory tract is a common entry route for many pathogens and an important delivery route for vaccination in the poultry industry. Immune responses in the avian lung have mostly been studied in vivo due to the lack of robust, relevant in vitro and ex vivo models mimicking the microenvironment. Precision-cut lung slices (PCLS) have the major advantages of maintaining the 3-dimensional architecture of the lung and includes heterogeneous cell populations. PCLS have been obtained from a number of mammalian species and from chicken embryos. However, as the embryonic lung is physiologically undifferentiated and immunologically immature, it is less suitable to examine complex host-pathogen interactions including antimicrobial responses. Here we prepared PCLS from immunologically mature chicken lungs, tested different culture conditions, and found that serum supplementation has a detrimental effect on the quality of PCLS. Viable cells in PCLS remained present for ≥ 40 days, as determined by viability assays and sustained motility of fluorescent mononuclear phagocytic cells. The PCLS were responsive to lipopolysaccharide stimulation, which induced the release of nitric oxide, IL-1β, type I interferons and IL-10. Mononuclear phagocytes within the tissue maintained phagocytic activity, with live cell imaging capturing interactions with latex beads and an avian pathogenic Escherichia coli strain. Finally, the PCLS were also shown to be permissive to infection with low pathogenic avian influenza viruses. Taken together, immunologically mature chicken PCLS provide a suitable model to simulate live organ responsiveness and cell dynamics, which can be readily exploited to examine host-pathogen interactions and inflammatory responses.
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Affiliation(s)
- Karen Jane Bryson
- Division of Infection and Immunity, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland EH25 9RG UK
| | - Damien Garrido
- INRAE, Université de Tours, UMR ISP, Centre Val de Loire, 37380 Nouzilly, France
| | - Marco Esposito
- Division of Developmental Biology, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland EH25 9RG UK
| | - Gerry McLachlan
- Division of Developmental Biology, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland EH25 9RG UK
| | - Paul Digard
- Division of Infection and Immunity, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland EH25 9RG UK
| | - Catherine Schouler
- INRAE, Université de Tours, UMR ISP, Centre Val de Loire, 37380 Nouzilly, France
| | - Rodrigo Guabiraba
- INRAE, Université de Tours, UMR ISP, Centre Val de Loire, 37380 Nouzilly, France
| | - Sascha Trapp
- INRAE, Université de Tours, UMR ISP, Centre Val de Loire, 37380 Nouzilly, France
| | - Lonneke Vervelde
- Division of Infection and Immunity, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, Edinburgh, Scotland EH25 9RG UK
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8
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Inventory of molecular markers affecting biological characteristics of avian influenza A viruses. Virus Genes 2019; 55:739-768. [PMID: 31428925 PMCID: PMC6831541 DOI: 10.1007/s11262-019-01700-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 08/09/2019] [Indexed: 12/20/2022]
Abstract
Avian influenza viruses (AIVs) circulate globally, spilling over into domestic poultry and causing zoonotic infections in humans. Fortunately, AIVs are not yet capable of causing sustained human-to-human infection; however, AIVs are still a high risk as future pandemic strains, especially if they acquire further mutations that facilitate human infection and/or increase pathogenesis. Molecular characterization of sequencing data for known genetic markers associated with AIV adaptation, transmission, and antiviral resistance allows for fast, efficient assessment of AIV risk. Here we summarize and update the current knowledge on experimentally verified molecular markers involved in AIV pathogenicity, receptor binding, replicative capacity, and transmission in both poultry and mammals with a broad focus to include data available on other AIV subtypes outside of A/H5N1 and A/H7N9.
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9
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Nogales A, Martinez-Sobrido L, Topham DJ, DeDiego ML. Modulation of Innate Immune Responses by the Influenza A NS1 and PA-X Proteins. Viruses 2018; 10:v10120708. [PMID: 30545063 PMCID: PMC6315843 DOI: 10.3390/v10120708] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 12/06/2018] [Accepted: 12/08/2018] [Indexed: 12/14/2022] Open
Abstract
Influenza A viruses (IAV) can infect a broad range of animal hosts, including humans. In humans, IAV causes seasonal annual epidemics and occasional pandemics, representing a serious public health and economic problem, which is most effectively prevented through vaccination. The defense mechanisms that the host innate immune system provides restrict IAV replication and infection. Consequently, to successfully replicate in interferon (IFN)-competent systems, IAV has to counteract host antiviral activities, mainly the production of IFN and the activities of IFN-induced host proteins that inhibit virus replication. The IAV multifunctional proteins PA-X and NS1 are virulence factors that modulate the innate immune response and virus pathogenicity. Notably, these two viral proteins have synergistic effects in the inhibition of host protein synthesis in infected cells, although using different mechanisms of action. Moreover, the control of innate immune responses by the IAV NS1 and PA-X proteins is subject to a balance that can determine virus pathogenesis and fitness, and recent evidence shows co-evolution of these proteins in seasonal viruses, indicating that they should be monitored for enhanced virulence. Importantly, inhibition of host gene expression by the influenza NS1 and/or PA-X proteins could be explored to develop improved live-attenuated influenza vaccines (LAIV) by modulating the ability of the virus to counteract antiviral host responses. Likewise, both viral proteins represent a reasonable target for the development of new antivirals for the control of IAV infections. In this review, we summarize the role of IAV NS1 and PA-X in controlling the antiviral response during viral infection.
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Affiliation(s)
- Aitor Nogales
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York, NY 14642, USA.
- Centro de Investigación en Sanidad Animal (CISA)-INIA, Valdeolmos, 28130 Madrid, Spain.
| | - Luis Martinez-Sobrido
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York, NY 14642, USA.
| | - David J Topham
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York, NY 14642, USA.
- David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York, NY 14642, USA.
| | - Marta L DeDiego
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York, NY 14642, USA.
- David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York, NY 14642, USA.
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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10
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Dou D, Revol R, Östbye H, Wang H, Daniels R. Influenza A Virus Cell Entry, Replication, Virion Assembly and Movement. Front Immunol 2018; 9:1581. [PMID: 30079062 PMCID: PMC6062596 DOI: 10.3389/fimmu.2018.01581] [Citation(s) in RCA: 289] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 06/26/2018] [Indexed: 12/20/2022] Open
Abstract
Influenza viruses replicate within the nucleus of the host cell. This uncommon RNA virus trait provides influenza with the advantage of access to the nuclear machinery during replication. However, it also increases the complexity of the intracellular trafficking that is required for the viral components to establish a productive infection. The segmentation of the influenza genome makes these additional trafficking requirements especially challenging, as each viral RNA (vRNA) gene segment must navigate the network of cellular membrane barriers during the processes of entry and assembly. To accomplish this goal, influenza A viruses (IAVs) utilize a combination of viral and cellular mechanisms to coordinate the transport of their proteins and the eight vRNA gene segments in and out of the cell. The aim of this review is to present the current mechanistic understanding for how IAVs facilitate cell entry, replication, virion assembly, and intercellular movement, in an effort to highlight some of the unanswered questions regarding the coordination of the IAV infection process.
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Affiliation(s)
- Dan Dou
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Rebecca Revol
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Henrik Östbye
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Hao Wang
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Robert Daniels
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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