1
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Chevalier C, Leymarie O, Sedano L, Da Costa B, Richard CA, Maisonnasse P, Réfregiers M, Jamme F, Le Goffic R. PB1-F2 amyloid-like fibers correlate with proinflammatory signaling and respiratory distress in influenza-infected mice. J Biol Chem 2021; 297:100885. [PMID: 34146545 PMCID: PMC8294585 DOI: 10.1016/j.jbc.2021.100885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/04/2021] [Accepted: 06/15/2021] [Indexed: 11/30/2022] Open
Abstract
PB1-F2 is a virulence factor of influenza A virus known to increase viral pathogenicity in mammalian hosts. PB1-F2 is an intrinsically disordered protein displaying a propensity to form amyloid-like fibers. However, the correlation between PB1-F2 structures and the resulting inflammatory response is unknown. Here, we used synchrotron-coupled Fourier transform-IR and deep UV microscopies to determine the presence of PB1-F2 fibers in influenza A virus–infected mice. In order to study the correlation between PB1-F2 structure and the inflammatory response, transgenic mice expressing luciferase under the control of an NF-κB promotor, allowing in vivo monitoring of inflammation, were intranasally instilled with monomeric, fibrillated, or truncated forms of recombinant PB1-F2. Our intravital NF-κB imaging, supported by cytokine quantification, clearly shows the proinflammatory effect of PB1-F2 fibers compared with N-terminal region of PB1-F2 unable to fibrillate. It is noteworthy that instillation of monomeric PB1-F2 of H5N1 virus induced a stronger inflammatory response when compared with prefibrillated PB1-F2 of H1N1 virus, suggesting mechanisms of virulence depending on PB1-F2 sequence. Finally, using whole-body plethysmography to measure volume changes in the lungs, we quantified the effects of the different forms of PB1-F2 on respiratory parameters. Thus, we conclude that PB1-F2–induced inflammation and respiratory distress are tightly correlated with sequence polymorphism and oligomerization status of the protein.
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Affiliation(s)
| | - Olivier Leymarie
- Université Paris-Saclay, UVSQ, INRAE, VIM, Jouy-en-Josas, France
| | - Laura Sedano
- Université Paris-Saclay, UVSQ, INRAE, VIM, Jouy-en-Josas, France
| | - Bruno Da Costa
- Université Paris-Saclay, UVSQ, INRAE, VIM, Jouy-en-Josas, France
| | | | | | - Matthieu Réfregiers
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, Gif-sur-Yvette, France
| | - Frédéric Jamme
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, Gif-sur-Yvette, France
| | - Ronan Le Goffic
- Université Paris-Saclay, UVSQ, INRAE, VIM, Jouy-en-Josas, France.
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2
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Lepont L, Leymarie O, Berlioz-Torrent C. [Cellular and viral determinants control HIV-1 virus-containing compartment expansion in infected macrophages]. Med Sci (Paris) 2020; 36:20-23. [PMID: 32014092 DOI: 10.1051/medsci/2019255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Leslie Lepont
- Université de Paris, Institut Cochin, Inserm, CNRS, laboratoire « Interactions hôte-virus », 27 rue du faubourg Saint Jacques, F-75014 Paris, France
| | - Olivier Leymarie
- Université de Paris, Institut Cochin, Inserm, CNRS, laboratoire « Interactions hôte-virus », 27 rue du faubourg Saint Jacques, F-75014 Paris, France
| | - Clarisse Berlioz-Torrent
- Université de Paris, Institut Cochin, Inserm, CNRS, laboratoire « Interactions hôte-virus », 27 rue du faubourg Saint Jacques, F-75014 Paris, France
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3
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Madjo U, Leymarie O, Frémont S, Kuster A, Nehlich M, Gallois-Montbrun S, Janvier K, Berlioz-Torrent C. LC3C Contributes to Vpu-Mediated Antagonism of BST2/Tetherin Restriction on HIV-1 Release through a Non-canonical Autophagy Pathway. Cell Rep 2017; 17:2221-2233. [PMID: 27880899 DOI: 10.1016/j.celrep.2016.10.045] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 09/05/2016] [Accepted: 10/13/2016] [Indexed: 11/19/2022] Open
Abstract
BST2 (bone marrow stromal antigen 2)/tetherin is a restriction factor of enveloped viruses, which blocks the release of viral particles. HIV-1 encodes proteins that antagonize this innate barrier, including the accessory protein Vpu. Here, we investigate whether the autophagy pathway and/or ATG proteins are hijacked by HIV-1 Vpu to circumvent BST2 restriction of viral release. We report that BST2 and Vpu are present in LC3-positive compartments. We found that Vpu selectively interacts with the ATG8 ortholog LC3C through the Vpu L63VEM66 sequence. This sequence is required for Vpu to antagonize BST2 restriction. LC3C expression favors the removal of BST2 from the HIV-1 budding site, and thus HIV-1 release in BST2-expressing cells. Additionally, ATG5 and beclin 1/ATG6, but not all the components of the autophagy pathway, act with LC3C to facilitate Vpu antagonism of BST2 restriction. Altogether, our data support the view that a non-canonical autophagy pathway reminiscent of LC3-associated phagocytosis contributes to Vpu counteraction of BST2 restriction.
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Affiliation(s)
- Ursula Madjo
- Inserm, U1016, Institut Cochin, 75014 Paris, France; Cnrs, UMR8104, 75014 Paris, France; University Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Olivier Leymarie
- Inserm, U1016, Institut Cochin, 75014 Paris, France; Cnrs, UMR8104, 75014 Paris, France; University Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Stéphane Frémont
- Inserm, U1016, Institut Cochin, 75014 Paris, France; Cnrs, UMR8104, 75014 Paris, France; University Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Aurelia Kuster
- Inserm, U1016, Institut Cochin, 75014 Paris, France; Cnrs, UMR8104, 75014 Paris, France; University Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Mélanie Nehlich
- Inserm, U1016, Institut Cochin, 75014 Paris, France; Cnrs, UMR8104, 75014 Paris, France; University Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Sarah Gallois-Montbrun
- Inserm, U1016, Institut Cochin, 75014 Paris, France; Cnrs, UMR8104, 75014 Paris, France; University Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Katy Janvier
- Inserm, U1016, Institut Cochin, 75014 Paris, France; Cnrs, UMR8104, 75014 Paris, France; University Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Clarisse Berlioz-Torrent
- Inserm, U1016, Institut Cochin, 75014 Paris, France; Cnrs, UMR8104, 75014 Paris, France; University Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France.
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4
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Leymarie O, Meyer L, Tafforeau L, Lotteau V, Costa BD, Delmas B, Chevalier C, Le Goffic R. Influenza virus protein PB1-F2 interacts with CALCOCO2 (NDP52) to modulate innate immune response. J Gen Virol 2017; 98:1196-1208. [PMID: 28613140 DOI: 10.1099/jgv.0.000782] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
PB1-F2 is a viral protein encoded by influenza A viruses (IAVs). PB1-F2 is implicated in virulence by triggering immune cell apoptosis and enhancing inflammation. To obtain an insight into the molecular mechanisms of PB1-F2-mediated virulence, we used the yeast two-hybrid approach to find new PB1-F2 cellular interactors. This allowed us to identify calcium-binding and coiled-coil domain 2 (CALCOCO2, also known as NDP52) as a binding partner of PB1-F2. Binding of PB1-F2 to CALCOCO2 was confirmed by pull-down. Surface plasmon resonance binding experiments enabled us to estimate the dissociation constant (Kd) of the two partners to be around 20 nM. Using bioinformatics tools, we designed a CALCOCO2 interaction map based on previous knowledge and showed a strong connection between this protein and the type I interferon production pathways and the I-κB kinase/NF-κB signalling pathway. NF-κB reporter assays in which CALCOCO2, MAVS and PB1-F2 were co-expressed showed a cooperation of these three proteins to increase the inflammatory response. By contrast, PB1-F2 inhibits the TBK1-dependent activation of an ISRE reporter plasmid. We also demonstrated that the signal transducer TRAF6 is implicated in the enhancement of NF-κB activity mediated by PB1-F2/CALCOCO2 binding. Altogether, this report provides evidence of an interaction link between PB1-F2 and human proteins, and allows a better understanding of the involvement of PB1-F2 in the pathologic process mediated by IAV.
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Affiliation(s)
- Olivier Leymarie
- VIM, INRA, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Léa Meyer
- VIM, INRA, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Lionel Tafforeau
- IMAP Team, Inserm Unit 851, 21, Av. T. Garnier, 69007 Lyon, France.,Present address: Laboratory of Cellular Biology, Research Institute for Biosciences, University of Mons-UMONS, Belgium
| | - Vincent Lotteau
- INSERM U1111, Lyon, France.,CIRI, Centre de Recherche en Infectiologie, Lyon, France.,Université de Lyon, France
| | - Bruno Da Costa
- VIM, INRA, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Bernard Delmas
- VIM, INRA, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | | | - Ronan Le Goffic
- VIM, INRA, Université Paris-Saclay, 78350, Jouy-en-Josas, France
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Meyer L, Leymarie O, Chevalier C, Esnault E, Moroldo M, Da Costa B, Georgeault S, Roingeard P, Delmas B, Quéré P, Le Goffic R. Transcriptomic profiling of a chicken lung epithelial cell line (CLEC213) reveals a mitochondrial respiratory chain activity boost during influenza virus infection. PLoS One 2017; 12:e0176355. [PMID: 28441462 PMCID: PMC5404788 DOI: 10.1371/journal.pone.0176355] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/10/2017] [Indexed: 11/17/2022] Open
Abstract
Avian Influenza virus (AIV) is a major concern for the global poultry industry. Since 2012, several countries have reported AIV outbreaks among domestic poultry. These outbreaks had tremendous impact on poultry production and socio-economic repercussion on farmers. In addition, the constant emergence of highly pathogenic AIV also poses a significant risk to human health. In this study, we used a chicken lung epithelial cell line (CLEC213) to gain a better understanding of the molecular consequences of low pathogenic AIV infection in their natural host. Using a transcriptome profiling approach based on microarrays, we identified a cluster of mitochondrial genes highly induced during the infection. Interestingly, most of the regulated genes are encoded by the mitochondrial genome and are involved in the oxidative phosphorylation metabolic pathway. The biological consequences of this transcriptomic induction result in a 2.5- to 4-fold increase of the ATP concentration within the infected cells. PB1-F2, a viral protein that targets the mitochondria was not found associated to the boost of activity of the respiratory chain. We next explored the possibility that ATP may act as a host-derived danger signal (through production of extracellular ATP) or as a boost to increase AIV replication. We observed that, despite the activation of the P2X7 purinergic receptor pathway, a 1mM ATP addition in the cell culture medium had no effect on the virus replication in our epithelial cell model. Finally, we found that oligomycin, a drug that inhibits the oxidative phosphorylation process, drastically reduced the AIV replication in CLEC213 cells, without apparent cellular toxicity. Collectively, our results suggest that AIV is able to boost the metabolic capacities of its avian host in order to provide the important energy needs required to produce progeny virus.
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Affiliation(s)
- Léa Meyer
- VIM, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | | | | | - Evelyne Esnault
- ISP, INRA, Université François Rabelais de Tours, UMR 1282, Nouzilly, France
| | - Marco Moroldo
- Centre de Ressources Biologiques pour la Génomique des Animaux Domestiques et d'Intérêt Economique, CRB GADIE INRA, Domaine de Vilvert, Jouy-en-Josas, France
| | - Bruno Da Costa
- VIM, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Sonia Georgeault
- Plateforme IBiSA de Microscopie Electronique, Université François Rabelais and CHRU de Tours, Tours, France
| | - Philippe Roingeard
- Plateforme IBiSA de Microscopie Electronique, Université François Rabelais and CHRU de Tours, Tours, France.,INSERM U966, Université François Rabelais and CHRU de Tours, Tours, France
| | - Bernard Delmas
- VIM, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Pascale Quéré
- ISP, INRA, Université François Rabelais de Tours, UMR 1282, Nouzilly, France
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6
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Chevalier C, Le Goffic R, Jamme F, Leymarie O, Réfrégiers M, Delmas B. Synchrotron Infrared and Deep UV Fluorescent Microspectroscopy Study of PB1-F2 β-Aggregated Structures in Influenza A Virus-infected Cells. J Biol Chem 2016; 291:9060-72. [PMID: 26896002 DOI: 10.1074/jbc.m115.710533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Indexed: 11/06/2022] Open
Abstract
PB1-F2 is a virulence factor of influenza A virus (IAV) whose functions remain misunderstood. The different roles of PB1-F2 may be linked to its structural polymorphism and to its propensity to assemble into oligomers and amyloid fibers in the vicinity of the membrane of IAV-infected cells. Here, we monitored the impact of PB1-F2 on the biochemical composition and protein structures of human epithelial pulmonary cells (A549) and monocytic cells (U937) upon IAV infection using synchrotron Fourier-transform infrared (FTIR) and deep UV (DUV) microscopies at the single-cell level. Cells were infected with a wild-type IAV and its PB1-F2 knock-out mutant for analyses at different times post-infection. IR spectra were recorded in each condition and processed to evaluate the change in the component band of the spectra corresponding to the amide I (secondary structure) and the CH stretching region (membrane). The IR spectra analysis revealed that expression of PB1-F2 in U937 cells, but not in A549 cells, results in the presence of a specific β-aggregate signature. Furthermore, the lipid membrane composition of U937 cells expressing PB1-F2 was also altered in a cell type-dependent manner. Using DUV microscopy and taking advantage of the high content of tryptophan residues in the sequence of PB1-F2 (5/90 aa), we showed that the increase of the autofluorescent signal recorded in monocytic cells could be correlated with the IR detection of β-aggregates. Altogether, our results constitute an important step forward in the understanding of the cell type-dependent function of PB1-F2.
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Affiliation(s)
| | - Ronan Le Goffic
- From the VIM, UR892, INRA, Université PARIS-SACLAY, 78350 Jouy-en-Josas and
| | - Frédéric Jamme
- the DISCO and SMIS Beamlines, Synchrotron SOLEIL, L'Orme des Merisiers, 91190 Saint-Aubin, Gif-sur Yvette, France
| | - Olivier Leymarie
- From the VIM, UR892, INRA, Université PARIS-SACLAY, 78350 Jouy-en-Josas and
| | - Matthieu Réfrégiers
- the DISCO and SMIS Beamlines, Synchrotron SOLEIL, L'Orme des Merisiers, 91190 Saint-Aubin, Gif-sur Yvette, France
| | - Bernard Delmas
- From the VIM, UR892, INRA, Université PARIS-SACLAY, 78350 Jouy-en-Josas and
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7
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Leymarie O, Jouvion G, Hervé PL, Chevalier C, Lorin V, Lecardonnel J, Da Costa B, Delmas B, Escriou N, Le Goffic R. Kinetic characterization of PB1-F2-mediated immunopathology during highly pathogenic avian H5N1 influenza virus infection. PLoS One 2013; 8:e57894. [PMID: 23469251 PMCID: PMC3585811 DOI: 10.1371/journal.pone.0057894] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/28/2013] [Indexed: 12/30/2022] Open
Abstract
The PB1-F2 protein encoded by influenza A viruses can contribute to virulence, a feature that is dependent of its sequence polymorphism. Whereas PB1-F2 from some H1N1 viruses were shown to exacerbate the inflammatory response within the airways, the contribution of PB1-F2 to highly pathogenic avian influenza virus (HPAIV) virulence in mammals remains poorly described. Using a H5N1 HPAIV strain isolated from duck and its PB1-F2 knocked-out mutant, we characterized the dynamics of PB1-F2-associated host response in a murine model of lethal pneumonia. The mean time of death was 10 days for the two viruses, allowing us to perform global transcriptomic analyses and detailed histological investigations of the infected lungs at multiple time points. At day 2 post-infection (pi), while no histopathological lesion was observed, PB1-F2 expression resulted in a significant inhibition of cellular pathways involved in macrophage activation and in a transcriptomic signature suggesting that it promotes damage to the epithelial barrier. At day 4 pi, the gene profile associated with PB1-F2 expression revealed dysfunctions in NK cells activity. At day 8 pi, PB1-F2 expression was strongly associated with increased transcription of genes encoding chemokines and cytokines implicated in the recruitment of granulocytes, as well as expression of a number of genes encoding enzymes expressed by neutrophils. These transcriptomic data were fully supported by the histopathological analysis of the mice lungs which evidenced more severe inflammatory lesions and enhanced recruitment of neutrophils in the context of PB1-F2 expression, and thus provided a functional corroboration to the insight obtained in this work. In summary, our study shows that PB1-F2 of H5N1 HPAIV markedly influences the expression of the host transcriptome in a different way than its H1N1 counterparts: H5N1 PB1-F2 first delays the initial immune response but increases the pulmonary inflammatory response during the late stages of infection.
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MESH Headings
- Animals
- Epithelial Cells/immunology
- Epithelial Cells/pathology
- Epithelial Cells/virology
- Female
- Gene Expression Regulation, Viral
- Gene Knockout Techniques
- Host-Pathogen Interactions
- Influenza A Virus, H5N1 Subtype/genetics
- Influenza A Virus, H5N1 Subtype/immunology
- Influenza A Virus, H5N1 Subtype/pathogenicity
- Killer Cells, Natural/immunology
- Killer Cells, Natural/pathology
- Killer Cells, Natural/virology
- Lung/immunology
- Lung/pathology
- Lung/virology
- Mice
- Neutrophils/immunology
- Neutrophils/pathology
- Neutrophils/virology
- Orthomyxoviridae Infections/immunology
- Orthomyxoviridae Infections/mortality
- Orthomyxoviridae Infections/pathology
- Orthomyxoviridae Infections/virology
- Pneumonia, Viral/immunology
- Pneumonia, Viral/mortality
- Pneumonia, Viral/pathology
- Pneumonia, Viral/virology
- Respiratory Mucosa/immunology
- Respiratory Mucosa/pathology
- Respiratory Mucosa/virology
- Species Specificity
- Survival Rate
- Transcriptome
- Viral Proteins/genetics
- Viral Proteins/immunology
- Virulence
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Affiliation(s)
- Olivier Leymarie
- Unité de Virologie et Immunologie Moléculaires, UR 892 INRA, Domaine de Vilvert, Jouy-en-Josas, France
| | - Grégory Jouvion
- Institut Pasteur, Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Epidémiologie, Paris, France
| | - Pierre-Louis Hervé
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Département de Virologie, Paris, France
- CNRS, URA30I5, Paris, France
- Univ. Paris Diderot, Sorbonne, Paris Cité, EA 302, Paris, France
| | - Christophe Chevalier
- Unité de Virologie et Immunologie Moléculaires, UR 892 INRA, Domaine de Vilvert, Jouy-en-Josas, France
| | - Valérie Lorin
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Département de Virologie, Paris, France
- CNRS, URA30I5, Paris, France
- Univ. Paris Diderot, Sorbonne, Paris Cité, EA 302, Paris, France
| | - Jérôme Lecardonnel
- Centre de Ressources Biologiques pour la Génomique des Animaux Domestiques et d'Intérêt Economique, CRB GADIE INRA, Domaine de Vilvert, Jouy-en-Josas, France
| | - Bruno Da Costa
- Unité de Virologie et Immunologie Moléculaires, UR 892 INRA, Domaine de Vilvert, Jouy-en-Josas, France
| | - Bernard Delmas
- Unité de Virologie et Immunologie Moléculaires, UR 892 INRA, Domaine de Vilvert, Jouy-en-Josas, France
| | - Nicolas Escriou
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Département de Virologie, Paris, France
- CNRS, URA30I5, Paris, France
- Univ. Paris Diderot, Sorbonne, Paris Cité, EA 302, Paris, France
- * E-mail: (RLG); (NE)
| | - Ronan Le Goffic
- Unité de Virologie et Immunologie Moléculaires, UR 892 INRA, Domaine de Vilvert, Jouy-en-Josas, France
- * E-mail: (RLG); (NE)
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Le Goffic R, Leymarie O, Chevalier C, Rebours E, Da Costa B, Vidic J, Descamps D, Sallenave JM, Rauch M, Samson M, Delmas B. Transcriptomic analysis of host immune and cell death responses associated with the influenza A virus PB1-F2 protein. PLoS Pathog 2011; 7:e1002202. [PMID: 21901097 PMCID: PMC3161975 DOI: 10.1371/journal.ppat.1002202] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 06/24/2011] [Indexed: 12/19/2022] Open
Abstract
Airway inflammation plays a major role in the pathogenesis of influenza viruses and can lead to a fatal outcome. One of the challenging objectives in the field of influenza research is the identification of the molecular bases associated to the immunopathological disorders developed during infection. While its precise function in the virus cycle is still unclear, the viral protein PB1-F2 is proposed to exert a deleterious activity within the infected host. Using an engineered recombinant virus unable to express PB1-F2 and its wild-type homolog, we analyzed and compared the pathogenicity and host response developed by the two viruses in a mouse model. We confirmed that the deletion of PB1-F2 renders the virus less virulent. The global transcriptomic analyses of the infected lungs revealed a potent impact of PB1-F2 on the response developed by the host. Thus, after two days post-infection, PB1-F2 invalidation severely decreased the number of genes activated by the host. PB1-F2 expression induced an increase in the number and level of expression of activated genes linked to cell death, inflammatory response and neutrophil chemotaxis. When generating interactive gene networks specific to PB1-F2, we identified IFN-γ as a central regulator of PB1-F2-regulated genes. The enhanced cell death of airway-recruited leukocytes was evidenced using an apoptosis assay, confirming the pro-apoptotic properties of PB1-F2. Using a NF-kB luciferase adenoviral vector, we were able to quantify in vivo the implication of NF-kB in the inflammation mediated by the influenza virus infection; we found that PB1-F2 expression intensifies the NF-kB activity. Finally, we quantified the neutrophil recruitment within the airways, and showed that this type of leukocyte is more abundant during the infection of the wild-type virus. Collectively, these data demonstrate that PB1-F2 strongly influences the early host response during IAV infection and provides new insights into the mechanisms by which PB1-F2 mediates virulence. Influenza A viruses may cause severe respiratory disease. PB1-F2, a viral protein identified in 2001 is suspected to play a role in influenza-related pneumonia. In order to understand the impact of PB1-F2 in the pathogenesis underlying Influenza A virus infection, we engineered a mutant virus unable to express PB1-F2. By the use of high-throughput gene expression assays, we compared the host responses of the wild-type-infected and the PB1-F2 mutant-infected mice. We identified that PB1-F2 expression enhances the immune cell death and inflammatory responses of mice. The inflammatory response mediated by the PB1-F2 expression leads to a massive recruitment of leukocytes within the air spaces, a feature that characterizes the influenza-mediated immunopathology. Our results suggest that PB1-F2 is a virulence factor implicated in the deregulation of the inflammatory response observed in acute influenza virus pneumonia. These data underlie the complexities of virus-host interactions and help us understand by which mechanisms Influenza viruses mediate severe respiratory diseases.
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Affiliation(s)
- Ronan Le Goffic
- Unité de Virologie et Immunologie Moléculaires, UR 892 INRA, Jouy-en-Josas, France.
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9
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Le Goffic R, Bouguyon E, Chevalier C, Vidic J, Da Costa B, Leymarie O, Bourdieu C, Decamps L, Dhorne-Pollet S, Delmas B. Influenza A virus protein PB1-F2 exacerbates IFN-beta expression of human respiratory epithelial cells. J Immunol 2010; 185:4812-23. [PMID: 20844191 DOI: 10.4049/jimmunol.0903952] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The PB1-F2 protein of the influenza A virus (IAV) contributes to viral pathogenesis by a mechanism that is not well understood. PB1-F2 was shown to modulate apoptosis and to be targeted by the CD8(+) T cell response. In this study, we examined the downstream effects of PB1-F2 protein during IAV infection by measuring expression of the cellular genes in response to infection with wild-type WSN/33 and PB1-F2 knockout viruses in human lung epithelial cells. Wild-type virus infection resulted in a significant induction of genes involved in innate immunity. Knocking out the PB1-F2 gene strongly decreased the magnitude of expression of cellular genes implicated in antiviral response and MHC class I Ag presentation, suggesting that PB1-F2 exacerbates innate immune response. Biological network analysis revealed the IFN pathway as a link between PB1-F2 and deregulated genes. Using quantitative RT-PCR and IFN-β gene reporter assay, we determined that PB1-F2 mediates an upregulation of IFN-β expression that is dependent on NF-κB but not on AP-1 and IFN regulatory factor-3 transcription factors. Recombinant viruses knocked out for the PB1-F2 and/or the nonstructural viral protein 1 (the viral antagonist of the IFN response) genes provide further evidence that PB1-F2 increases IFN-β expression and that nonstructural viral protein 1 strongly antagonizes the effect of PB1-F2 on the innate response. Finally, we compared the effect of PB1-F2 variants taken from several IAV strains on IFN-β expression and found that PB1-F2-mediated IFN-β induction is significantly influenced by its amino acid sequence, demonstrating its importance in the host cell response triggered by IAV infection.
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Affiliation(s)
- Ronan Le Goffic
- Unité de Virologie et Immunologie Moléculaires, Unité de Recherche 892 Institut National de la Recherche Agronomique, Domaine de Vilvert, Jouy-en-Josas, France.
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