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Khalil AM, Nogales A, Martínez-Sobrido L, Mostafa A. Antiviral responses versus virus-induced cellular shutoff: a game of thrones between influenza A virus NS1 and SARS-CoV-2 Nsp1. Front Cell Infect Microbiol 2024; 14:1357866. [PMID: 38375361 PMCID: PMC10875036 DOI: 10.3389/fcimb.2024.1357866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 01/16/2024] [Indexed: 02/21/2024] Open
Abstract
Following virus recognition of host cell receptors and viral particle/genome internalization, viruses replicate in the host via hijacking essential host cell machinery components to evade the provoked antiviral innate immunity against the invading pathogen. Respiratory viral infections are usually acute with the ability to activate pattern recognition receptors (PRRs) in/on host cells, resulting in the production and release of interferons (IFNs), proinflammatory cytokines, chemokines, and IFN-stimulated genes (ISGs) to reduce virus fitness and mitigate infection. Nevertheless, the game between viruses and the host is a complicated and dynamic process, in which they restrict each other via specific factors to maintain their own advantages and win this game. The primary role of the non-structural protein 1 (NS1 and Nsp1) of influenza A viruses (IAV) and the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respectively, is to control antiviral host-induced innate immune responses. This review provides a comprehensive overview of the genesis, spatial structure, viral and cellular interactors, and the mechanisms underlying the unique biological functions of IAV NS1 and SARS-CoV-2 Nsp1 in infected host cells. We also highlight the role of both non-structural proteins in modulating viral replication and pathogenicity. Eventually, and because of their important role during viral infection, we also describe their promising potential as targets for antiviral therapy and the development of live attenuated vaccines (LAV). Conclusively, both IAV NS1 and SARS-CoV-2 Nsp1 play an important role in virus-host interactions, viral replication, and pathogenesis, and pave the way to develop novel prophylactic and/or therapeutic interventions for the treatment of these important human respiratory viral pathogens.
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Affiliation(s)
- Ahmed Magdy Khalil
- Disease Intervention & Prevention and Host Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, TX, United States
- Department of Zoonotic Diseases, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Aitor Nogales
- Center for Animal Health Research, CISA-INIA-CSIC, Madrid, Spain
| | - Luis Martínez-Sobrido
- Disease Intervention & Prevention and Host Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Ahmed Mostafa
- Disease Intervention & Prevention and Host Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, TX, United States
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza, Egypt
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Different but Not Unique: Deciphering the Immunity of the Jamaican Fruit Bat by Studying Its Viriome. Viruses 2022; 14:v14020238. [PMID: 35215832 PMCID: PMC8879847 DOI: 10.3390/v14020238] [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: 12/08/2021] [Revised: 01/20/2022] [Accepted: 01/23/2022] [Indexed: 02/04/2023] Open
Abstract
A specialized and fine-tuned immune response of bats upon infection with viruses is believed to provide the basis for a “friendly” coexistence with these pathogens, which are often lethal for humans and other mammals. First insights into the immunity of bats suggest that bats have evolved to possess their own strategies to cope with viral infections. Yet, the molecular details for this innocuous coexistence remain poorly described and bat infection models are the key to unveiling these secrets. In Jamaican fruit bats (Artibeus jamaicensis), a New World bat species, infection experiments with its (putative) natural viral pathogens Tacaribe virus (TCRV), rabies virus (RABV), and the bat influenza A virus (IAV) H18N11, have contributed to an accurate, though still incomplete, representation of the bat-imposed immunity. Surprisingly, though many aspects of their innate and adaptive immune responses differ from that of the human immune response, such as a contraction of the IFN locus and reduction in the number of immunoglobulin subclasses, variations could also be observed between Jamaican fruit bats and other bat species.
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Boergeling Y, Brunotte L, Ludwig S. Dynamic phospho-modification of viral proteins as a crucial regulatory layer of influenza A virus replication and innate immune responses. Biol Chem 2021; 402:1493-1504. [PMID: 34062629 DOI: 10.1515/hsz-2021-0241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 05/18/2021] [Indexed: 02/07/2023]
Abstract
Influenza viruses are small RNA viruses with a genome of about 13 kb. Because of this limited coding capacity, viral proteins have evolved to fulfil multiple functions in the infected cell. This implies that there must be mechanisms allowing to dynamically direct protein action to a distinct activity in a spatio-temporal manner. Furthermore, viruses exploit many cellular processes, which also have to be dynamically regulated during the viral replication cycle. Phosphorylation and dephosphorylation of proteins are fundamental for the control of many cellular responses. There is accumulating evidence that this mechanism represents a so far underestimated level of regulation in influenza virus replication. Here, we focus on the current knowledge of dynamics of phospho-modifications in influenza virus replication and show recent examples of findings underlining the crucial role of phosphorylation in viral transport processes as well as activation and counteraction of the innate immune response.
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Affiliation(s)
- Yvonne Boergeling
- Institute of Virology and Interdisciplinary Center for Clinical Research (IZKF), Medical Faculty, University of Münster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
| | - Linda Brunotte
- Institute of Virology and Interdisciplinary Center for Clinical Research (IZKF), Medical Faculty, University of Münster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
| | - Stephan Ludwig
- Institute of Virology and Interdisciplinary Center for Clinical Research (IZKF), Medical Faculty, University of Münster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
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Ludwig S, Hrincius ER, Boergeling Y. The Two Sides of the Same Coin-Influenza Virus and Intracellular Signal Transduction. Cold Spring Harb Perspect Med 2021; 11:a038513. [PMID: 31871235 PMCID: PMC7778220 DOI: 10.1101/cshperspect.a038513] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cells respond to extracellular agents by activation of intracellular signaling pathways. Viruses can be regarded as such agents, leading to a firework of signaling inside the cell, primarily induced by pathogen-associated molecular patterns (PAMPs) that provoke safeguard mechanisms to defend from the invader. In the constant arms race between pathogen and cellular defense, viruses not only have evolved mechanisms to suppress or misuse supposedly antiviral signaling processes for their own benefit but also actively induce signaling to promote replication. This creates viral dependencies that may be exploited for novel strategies of antiviral intervention. Here, we will summarize the current knowledge of activation and function of influenza virus-induced signaling pathways with a focus on nuclear factor (NF)-κB signaling, mitogen-activated protein kinase cascades, and the phosphatidylinositol-3-kinase pathway. We will discuss the opportunities and drawbacks of targeting these signaling pathways for antiviral intervention.
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Affiliation(s)
- Stephan Ludwig
- Institute of Virology Muenster, University of Muenster, 48149 Muenster, Germany
| | - Eike R Hrincius
- Institute of Virology Muenster, University of Muenster, 48149 Muenster, Germany
| | - Yvonne Boergeling
- Institute of Virology Muenster, University of Muenster, 48149 Muenster, Germany
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Mutations in the Neuraminidase-Like Protein of Bat Influenza H18N11 Virus Enhance Virus Replication in Mammalian Cells, Mice, and Ferrets. J Virol 2020; 94:JVI.01416-19. [PMID: 31801857 DOI: 10.1128/jvi.01416-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/25/2019] [Indexed: 11/20/2022] Open
Abstract
To characterize bat influenza H18N11 virus, we propagated a reverse genetics-generated H18N11 virus in Madin-Darby canine kidney subclone II cells and detected two mammal-adapting mutations in the neuraminidase (NA)-like protein (NA-F144C and NA-T342A, N2 numbering) that increased the virus titers in three mammalian cell lines (i.e., Madin-Darby canine kidney, Madin-Darby canine kidney subclone II, and human lung adenocarcinoma [Calu-3] cells). In mice, wild-type H18N11 virus replicated only in the lungs of the infected animals, whereas the NA-T342A and NA-F144C/T342A mutant viruses were detected in the nasal turbinates, in addition to the lungs. Bat influenza viruses have not been tested for their virulence or organ tropism in ferrets. We detected wild-type and single mutant viruses each possessing NA-F144C or NA-T342A in the nasal turbinates of one or several infected ferrets, respectively. A mutant virus possessing both the NA-F144C and NA-T342A mutations was isolated from both the lung and the trachea, suggesting that it has a broader organ tropism than the wild-type virus. However, none of the H18N11 viruses caused symptoms in mice or ferrets. The NA-F144C/T342A double mutation did not substantially affect virion morphology or the release of virions from cells. Collectively, our data demonstrate that the propagation of bat influenza H18N11 virus in mammalian cells can result in mammal-adapting mutations that may increase the replicative ability and/or organ tropism of the virus; overall, however, these viruses did not replicate to high titers throughout the respiratory tract of mice and ferrets.IMPORTANCE Bats are reservoirs for several severe zoonotic pathogens. The genomes of influenza A viruses of the H17N10 and H18N11 subtypes have been identified in bats, but no live virus has been isolated. The characterization of artificially generated bat influenza H18N11 virus in mammalian cell lines and animal models revealed that this virus can acquire mammal-adapting mutations that may increase its zoonotic potential; however, the wild-type and mutant viruses did not replicate to high titers in all infected animals.
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Nogales A, Aydillo T, Ávila-Pérez G, Escalera A, Chiem K, Cadagan R, DeDiego ML, Li F, García-Sastre A, Martínez-Sobrido L. Functional Characterization and Direct Comparison of Influenza A, B, C, and D NS1 Proteins in vitro and in vivo. Front Microbiol 2019; 10:2862. [PMID: 31921042 PMCID: PMC6927920 DOI: 10.3389/fmicb.2019.02862] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/26/2019] [Indexed: 12/24/2022] Open
Abstract
Influenza viruses are important pathogens that affect multiple animal species, including humans. There are four types of influenza viruses: A, B, C, and D (IAV, IBV, ICV, and IDV, respectively). IAV and IBV are currently circulating in humans and are responsible of seasonal epidemics (IAV and IBV) and occasional pandemics (IAV). ICV is known to cause mild infections in humans and pigs, while the recently identified IDV primarily affect cattle and pigs. Influenza non-structural protein 1 (NS1) is a multifunctional protein encoded by the NS segment in all influenza types. The main function of NS1 is to counteract the host antiviral defense, including the production of interferon (IFN) and IFN-stimulated genes (ISGs), and therefore is considered an important viral pathogenic factor. Despite of homologous functions, the NS1 protein from the diverse influenza types share little amino acid sequence identity, suggesting possible differences in their mechanism(s) of action, interaction(s) with host factors, and contribution to viral replication and/or pathogenesis. In addition, although the NS1 protein of IAV, IBV and, to some extent ICV, have been previously studied, it is unclear if IDV NS1 has similar properties. Using an approach that allow us to express NS1 independently of the nuclear export protein from the viral NS segment, we have generated recombinant IAV expressing IAV, IBV, ICV, and IDV NS1 proteins. Although recombinant viruses expressing heterotypic (IBV, ICV, and IDV) NS1 proteins were able to replicate similarly in canine MDCK cells, their viral fitness was impaired in human A549 cells and they were highly attenuated in vivo. Our data suggest that despite the similarities to effectively counteract innate immune responses in vitro, the NS1 proteins of IBV, ICV, or IDV do not fully complement the functions of IAV NS1, resulting in deficient viral replication and pathogenesis in vivo.
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Affiliation(s)
- Aitor Nogales
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, United States
- Centro de Investigación en Sanidad Animal, Madrid, Spain
| | - Teresa Aydillo
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Gines Ávila-Pérez
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, United States
| | - Alba Escalera
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Kevin Chiem
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, United States
| | - Richard Cadagan
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Marta L. DeDiego
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Feng Li
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD, United States
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Luis Martínez-Sobrido
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, United States
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Specific Mutations in the PB2 Protein of Influenza A Virus Compensate for the Lack of Efficient Interferon Antagonism of the NS1 Protein of Bat Influenza A-Like Viruses. J Virol 2018; 92:JVI.02021-17. [PMID: 29321309 DOI: 10.1128/jvi.02021-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/03/2018] [Indexed: 02/01/2023] Open
Abstract
Recently, two new influenza A-like viruses have been discovered in bats, A/little yellow-shouldered bat/Guatemala/060/2010 (HL17NL10) and A/flat-faced bat/Peru/033/2010 (HL18NL11). The hemagglutinin (HA)-like (HL) and neuraminidase (NA)-like (NL) proteins of these viruses lack hemagglutination and neuraminidase activities, despite their sequence and structural homologies with the HA and NA proteins of conventional influenza A viruses. We have now investigated whether the NS1 proteins of the HL17NL10 and HL18NL11 viruses can functionally replace the NS1 protein of a conventional influenza A virus. For this purpose, we generated recombinant influenza A/Puerto Rico/8/1934 (PR8) H1N1 viruses containing the NS1 protein of the PR8 wild-type, HL17NL10, and HL18NL11 viruses. These viruses (r/NS1PR8, r/NS1HL17, and r/NS1HL18, respectively) were tested for replication in bat and nonbat mammalian cells and in mice. Our results demonstrate that the r/NS1HL17 and r/NS1HL18 viruses are attenuated in vitro and in vivo However, the bat NS1 recombinant viruses showed a phenotype similar to that of the r/NS1PR8 virus in STAT1-/- human A549 cells and mice, both in vitro and in vivo systems being unable to respond to interferon (IFN). Interestingly, multiple mouse passages of the r/NS1HL17 and r/NS1HL18 viruses resulted in selection of mutant viruses containing single amino acid mutations in the viral PB2 protein. In contrast to the parental viruses, virulence and IFN antagonism were restored in the selected PB2 mutants. Our results indicate that the NS1 protein of bat influenza A-like viruses is less efficient than the NS1 protein of its conventional influenza A virus NS1 counterpart in antagonizing the IFN response and that this deficiency can be overcome by the influenza virus PB2 protein.IMPORTANCE Significant gaps in our understanding of the basic features of the recently discovered bat influenza A-like viruses HL17NL10 and HL18NL11 remain. The basic biology of these unique viruses displays both similarities to and differences from the basic biology of conventional influenza A viruses. Here, we show that recombinant influenza A viruses containing the NS1 protein from HL17NL10 and HL18NL11 are attenuated. This attenuation was mediated by their inability to antagonize the type I IFN response. However, this deficiency could be compensated for by single amino acid replacements in the PB2 gene. Our results unravel a functional divergence between the NS1 proteins of bat influenza A-like and conventional influenza A viruses and demonstrate an interplay between the viral PB2 and NS1 proteins to antagonize IFN.
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