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Aghajani Mir M. Vault RNAs (vtRNAs): Rediscovered non-coding RNAs with diverse physiological and pathological activities. Genes Dis 2024; 11:772-787. [PMID: 37692527 PMCID: PMC10491885 DOI: 10.1016/j.gendis.2023.01.014] [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: 07/26/2022] [Accepted: 01/16/2023] [Indexed: 04/05/2023] Open
Abstract
The physicochemical characteristics of RNA admit non-coding RNAs to perform a different range of biological acts through various mechanisms and are involved in regulating a diversity of fundamental processes. Notably, some reports of pathological conditions have proved abnormal expression of many non-coding RNAs guides the ailment. Vault RNAs are a class of non-coding RNAs containing stem regions or loops with well-conserved sequence patterns that play a fundamental role in the function of vault particles through RNA-ligand, RNA-RNA, or RNA-protein interactions. Taken together, vault RNAs have been proposed to be involved in a variety of functions such as cell proliferation, nucleocytoplasmic transport, intracellular detoxification processes, multidrug resistance, apoptosis, and autophagy, and serve as microRNA precursors and signaling pathways. Despite decades of investigations devoted, the biological function of the vault particle or the vault RNAs is not yet completely cleared. In this review, the current scientific assertions of the vital vault RNAs functions were discussed.
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Affiliation(s)
- Mahsa Aghajani Mir
- Deputy of Research and Technology, Health Research Institute, Babol University of Medical Sciences, Babol 47176-4774, Iran
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2
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Blake ME, Kleinpeter AB, Jureka AS, Petit CM. Structural Investigations of Interactions between the Influenza a Virus NS1 and Host Cellular Proteins. Viruses 2023; 15:2063. [PMID: 37896840 PMCID: PMC10612106 DOI: 10.3390/v15102063] [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: 08/22/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
The Influenza A virus is a continuous threat to public health that causes yearly epidemics with the ever-present threat of the virus becoming the next pandemic. Due to increasing levels of resistance, several of our previously used antivirals have been rendered useless. There is a strong need for new antivirals that are less likely to be susceptible to mutations. One strategy to achieve this goal is structure-based drug development. By understanding the minute details of protein structure, we can develop antivirals that target the most conserved, crucial regions to yield the highest chances of long-lasting success. One promising IAV target is the virulence protein non-structural protein 1 (NS1). NS1 contributes to pathogenicity through interactions with numerous host proteins, and many of the resulting complexes have been shown to be crucial for virulence. In this review, we cover the NS1-host protein complexes that have been structurally characterized to date. By bringing these structures together in one place, we aim to highlight the strength of this field for drug discovery along with the gaps that remain to be filled.
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Affiliation(s)
| | | | | | - Chad M. Petit
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.E.B.)
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Kim HJ, Han CW, Jeong MS, Jang SB. Structural study of novel vaccinia virus E3L and dsRNA-dependent protein kinase complex. Biochem Biophys Res Commun 2023; 665:1-9. [PMID: 37146409 DOI: 10.1016/j.bbrc.2023.04.107] [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: 04/10/2023] [Revised: 04/26/2023] [Accepted: 04/28/2023] [Indexed: 05/07/2023]
Abstract
E3L (RNA-binding protein E3) is one of the key IFN resistance genes encoded by VV and consists of 190 amino acids with a highly conserved carboxy-terminal double-stranded RNA-binding domain (dsRBD). PKR (dsRNA-dependent protein kinase) is an IFN-induced protein involved in anti-cell and antiviral activity. PKR inhibits the initiation of translation through alpha subunit of the initiation factor eIF2 (eIF2α) and mediates several transcription factors such as NF-κB, p53 or STATs. Activated PKR also induces apoptosis in vaccinia virus infection. E3L is required for viral IFN resistance and directly binds to PKR to block activation of PKR. In this work, we determined the three-dimensional complex structure of E3L and PKR using cryo-EM and determined the important residues involved in the interaction. In addition, PKR peptide binds to E3L and can increase protein levels of phosphorus-PKR and phosphorus-eIF2α-induced cell apoptosis through upregulation of phosphorus-PKR in HEK293 cells. Taken together, structural insights into E3L and PKR will provide a new optimization and development of vaccinia virus drugs.
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Affiliation(s)
- Hyeon Jin Kim
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan, 46241, Republic of Korea
| | - Chang Woo Han
- Insitute of Systems Biology, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan, 46241, Republic of Korea
| | - Mi Suk Jeong
- Insitute for Plastic Information and Energy Materials and Sustainable Utilization of Photovoltaic Energy Research Center, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan, 46241, Republic of Korea; GJMEDI INC., Republic of Korea.
| | - Se Bok Jang
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan, 46241, Republic of Korea; Insitute of Systems Biology, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan, 46241, Republic of Korea.
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Strategies of Influenza A Virus to Ensure the Translation of Viral mRNAs. Pathogens 2022; 11:pathogens11121521. [PMID: 36558855 PMCID: PMC9783940 DOI: 10.3390/pathogens11121521] [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: 11/23/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
Viruses are obligatorily intracellular pathogens. To generate progeny virus particles, influenza A viruses (IAVs) have to divert the cellular machinery to ensure sufficient translation of viral mRNAs. To this end, several strategies have been exploited by IAVs, such as host gene shutoff, suppression of host innate immune responses, and selective translation of viral mRNAs. Various IAV proteins are responsible for host gene shutoff, e.g., NS1, PA-X, and RdRp, through inhibition of cellular gene transcription, suppression of cellular RNA processing, degradation of cellular RNAs, and blockage of cellular mRNA export from the nucleus. Host shutoff should suppress the innate immune responses and also increase the translation of viral mRNAs indirectly due to the reduced competition from cellular mRNAs for cellular translational machinery. However, many other mechanisms are also responsible for the suppression of innate immune responses by IAV, such as prevention of the detection of the viral RNAs by the RLRs, inhibition of the activities of proteins involved in signaling events of interferon production, and inhibition of the activities of interferon-stimulated genes, mainly through viral NS1, PB1-F2, and PA-X proteins. IAV mRNAs may be selectively translated in favor of cellular mRNAs through interacting with viral and/or cellular proteins, such as NS1, PABPI, and/or IFIT2, in the 5'-UTR of viral mRNAs. This review briefly summarizes the strategies utilized by IAVs to ensure sufficient translation of viral mRNAs focusing on recent developments.
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Varghese PM, Kishore U, Rajkumari R. Innate and adaptive immune responses against Influenza A Virus: Immune evasion and vaccination strategies. Immunobiology 2022; 227:152279. [DOI: 10.1016/j.imbio.2022.152279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 11/25/2022]
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Koçmar T, Çağlayan E, Rayaman E, Nagata K, Turan K. Human sorting nexin 2 protein interacts with Influenza A virus PA protein and has a negative regulatory effect on the virus replication. Mol Biol Rep 2021; 49:497-510. [PMID: 34817777 PMCID: PMC8611637 DOI: 10.1007/s11033-021-06906-9] [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: 05/31/2021] [Accepted: 10/29/2021] [Indexed: 11/03/2022]
Abstract
Background Replication of the influenza A viruses occurs in the cells through the viral RdRP consisting of PB1, PB2, and PA. Several cellular proteins are involved in these processes. This study aims to reveal the interaction between human SNX2 protein and the PA protein and the effects of the SNX2 on the virus replication. Results To identify potential host interacting proteins to the PA, yeast two-hybrid assay was carried out with HEK293 cell cDNA library and the PA as a bait. We focused on SNX2 protein, which interacts with the PA in the yeast cells. By using the co-immunoprecipitation assays, it has been demonstrated that the amino-terminal part of the PA was important for binding to the SNX2. Immunolocalization of the proteins in HeLa cells supported this interaction. Knockdown of the SNX2 with siRNA in the cells resulted in a significant increase in both viral transcripts and virus growth. However, the increase of SNX2 in transfected cells didn’t cause a significant change in the viral RdRP activity in minireplicon assay. This may suggest that the negative effect of SNX2 on the virus replication could be saturated with its authentic intra-cellular amount. Conclusions This study revealed that the SNX2 and PA protein interact with each other in both yeast and HEK293 cells, and the SNX2 has a negative regulatory function on the virus replication. However, more knowledge is required to elucidate the action mechanism of the SNX2 on the influenza A virus replication at the molecular level. Supplementary Information The online version contains supplementary material available at 10.1007/s11033-021-06906-9.
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Affiliation(s)
- Tuğba Koçmar
- Institute of Health Sciences, Marmara University, Istanbul, Turkey
| | - Elif Çağlayan
- University of Health Sciences Kartal Koşuyolu High Speciality Educational and Research Hospital, Istanbul, Turkey
| | - Erkan Rayaman
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Marmara University, Istanbul, Turkey
| | - Kyosuke Nagata
- Department of Infection Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kadir Turan
- Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Marmara University, Istanbul, Turkey.
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Structure and Activities of the NS1 Influenza Protein and Progress in the Development of Small-Molecule Drugs. Int J Mol Sci 2021; 22:ijms22084242. [PMID: 33921888 PMCID: PMC8074201 DOI: 10.3390/ijms22084242] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/18/2021] [Accepted: 04/18/2021] [Indexed: 11/30/2022] Open
Abstract
The influenza virus causes human disease on a global scale and significant morbidity and mortality. The existing vaccination regime remains vulnerable to antigenic drift, and more seriously, a small number of viral mutations could lead to drug resistance. Therefore, the development of a new additional therapeutic small molecule-based anti-influenza virus is urgently required. The NS1 influenza gene plays a pivotal role in the suppression of host antiviral responses, especially by inhibiting interferon (IFN) production and the activities of antiviral proteins, such as dsRNA-dependent serine/threonine-protein kinase R (PKR) and 2′-5′-oligoadenylate synthetase (OAS)/RNase L. NS1 also modulates important aspects of viral RNA replication, viral protein synthesis, and virus replication cycle. Taken together, small molecules that target NS1 are believed to offer a means of developing new anti-influenza drugs.
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Roles of the Non-Structural Proteins of Influenza A Virus. Pathogens 2020; 9:pathogens9100812. [PMID: 33023047 PMCID: PMC7600879 DOI: 10.3390/pathogens9100812] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 09/29/2020] [Accepted: 10/01/2020] [Indexed: 12/11/2022] Open
Abstract
Influenza A virus (IAV) is a segmented, negative single-stranded RNA virus that causes seasonal epidemics and has a potential for pandemics. Several viral proteins are not packed in the IAV viral particle and only expressed in the infected host cells. These proteins are named non-structural proteins (NSPs), including NS1, PB1-F2 and PA-X. They play a versatile role in the viral life cycle by modulating viral replication and transcription. More importantly, they also play a critical role in the evasion of the surveillance of host defense and viral pathogenicity by inducing apoptosis, perturbing innate immunity, and exacerbating inflammation. Here, we review the recent advances of these NSPs and how the new findings deepen our understanding of IAV–host interactions and viral pathogenesis.
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Wan Q, Song D, Li H, He ML. Stress proteins: the biological functions in virus infection, present and challenges for target-based antiviral drug development. Signal Transduct Target Ther 2020; 5:125. [PMID: 32661235 PMCID: PMC7356129 DOI: 10.1038/s41392-020-00233-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/26/2020] [Accepted: 06/13/2020] [Indexed: 02/06/2023] Open
Abstract
Stress proteins (SPs) including heat-shock proteins (HSPs), RNA chaperones, and ER associated stress proteins are molecular chaperones essential for cellular homeostasis. The major functions of HSPs include chaperoning misfolded or unfolded polypeptides, protecting cells from toxic stress, and presenting immune and inflammatory cytokines. Regarded as a double-edged sword, HSPs also cooperate with numerous viruses and cancer cells to promote their survival. RNA chaperones are a group of heterogeneous nuclear ribonucleoproteins (hnRNPs), which are essential factors for manipulating both the functions and metabolisms of pre-mRNAs/hnRNAs transcribed by RNA polymerase II. hnRNPs involve in a large number of cellular processes, including chromatin remodelling, transcription regulation, RNP assembly and stabilization, RNA export, virus replication, histone-like nucleoid structuring, and even intracellular immunity. Dysregulation of stress proteins is associated with many human diseases including human cancer, cardiovascular diseases, neurodegenerative diseases (e.g., Parkinson’s diseases, Alzheimer disease), stroke and infectious diseases. In this review, we summarized the biologic function of stress proteins, and current progress on their mechanisms related to virus reproduction and diseases caused by virus infections. As SPs also attract a great interest as potential antiviral targets (e.g., COVID-19), we also discuss the present progress and challenges in this area of HSP-based drug development, as well as with compounds already under clinical evaluation.
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Affiliation(s)
- Qianya Wan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Dan Song
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Huangcan Li
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Ming-Liang He
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China. .,CityU Shenzhen Research Institute, Shenzhen, China.
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Differential Modulation of Innate Immune Responses in Human Primary Cells by Influenza A Viruses Carrying Human or Avian Nonstructural Protein 1. J Virol 2019; 94:JVI.00999-19. [PMID: 31597767 PMCID: PMC6912104 DOI: 10.1128/jvi.00999-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/29/2019] [Indexed: 12/22/2022] Open
Abstract
Influenza A viruses (IAVs) cause seasonal epidemics which result in an important health and economic burden. Wild aquatic birds are the natural host of IAV. However, IAV can infect diverse hosts, including humans, domestic poultry, pigs, and others. IAVs circulating in animals occasionally cross the species barrier, infecting humans, which results in mild to very severe disease. In some cases, these viruses can acquire the ability to be transmitted among humans and initiate a pandemic. The nonstructural 1 (NS1) protein of IAV is an important antagonist of the innate immune response. In this study, using recombinant viruses and primary human cells, we show that NS1 proteins from human and avian hosts show intrinsic differences in the modulation of the innate immunity in human dendritic cells and epithelial cells, as well as different cellular localization dynamics in infected cells. The influenza A virus (IAV) nonstructural protein 1 (NS1) contributes to disease pathogenesis through the inhibition of host innate immune responses. Dendritic cells (DCs) release interferons (IFNs) and proinflammatory cytokines and promote adaptive immunity upon viral infection. In order to characterize the strain-specific effects of IAV NS1 on human DC activation, we infected human DCs with a panel of recombinant viruses with the same backbone (A/Puerto Rico/08/1934) expressing different NS1 proteins from human and avian origin. We found that these viruses induced a clearly distinct phenotype in DCs. Specifically, viruses expressing NS1 from human IAV (either H1N1 or H3N2) induced higher levels of expression of type I (IFN-α and IFN-β) and type III (IFN-λ1 to IFNλ3) IFNs than viruses expressing avian IAV NS1 proteins (H5N1, H7N9, and H7N2), but the differences observed in the expression levels of proinflammatory cytokines like tumor necrosis factor alpha (TNF-α) or interleukin-6 (IL-6) were not significant. In addition, using imaging flow cytometry, we found that human and avian NS1 proteins segregate based on their subcellular trafficking dynamics, which might be associated with the different innate immune profile induced in DCs by viruses expressing those NS1 proteins. Innate immune responses induced by our panel of IAV recombinant viruses were also characterized in normal human bronchial epithelial cells, and the results were consistent with those in DCs. Altogether, our results reveal an increased ability of NS1 from avian viruses to antagonize innate immune responses in human primary cells compared to the ability of NS1 from human viruses, which could contribute to the severe disease induced by avian IAV in humans. IMPORTANCE Influenza A viruses (IAVs) cause seasonal epidemics which result in an important health and economic burden. Wild aquatic birds are the natural host of IAV. However, IAV can infect diverse hosts, including humans, domestic poultry, pigs, and others. IAVs circulating in animals occasionally cross the species barrier, infecting humans, which results in mild to very severe disease. In some cases, these viruses can acquire the ability to be transmitted among humans and initiate a pandemic. The nonstructural 1 (NS1) protein of IAV is an important antagonist of the innate immune response. In this study, using recombinant viruses and primary human cells, we show that NS1 proteins from human and avian hosts show intrinsic differences in the modulation of the innate immunity in human dendritic cells and epithelial cells, as well as different cellular localization dynamics in infected cells.
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Chua SCJH, Tan HQ, Engelberg D, Lim LHK. Alternative Experimental Models for Studying Influenza Proteins, Host-Virus Interactions and Anti-Influenza Drugs. Pharmaceuticals (Basel) 2019; 12:E147. [PMID: 31575020 PMCID: PMC6958409 DOI: 10.3390/ph12040147] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 12/14/2022] Open
Abstract
Ninety years after the discovery of the virus causing the influenza disease, this malady remains one of the biggest public health threats to mankind. Currently available drugs and vaccines only partially reduce deaths and hospitalizations. Some of the reasons for this disturbing situation stem from the sophistication of the viral machinery, but another reason is the lack of a complete understanding of the molecular and physiological basis of viral infections and host-pathogen interactions. Even the functions of the influenza proteins, their mechanisms of action and interaction with host proteins have not been fully revealed. These questions have traditionally been studied in mammalian animal models, mainly ferrets and mice (as well as pigs and non-human primates) and in cell lines. Although obviously relevant as models to humans, these experimental systems are very complex and are not conveniently accessible to various genetic, molecular and biochemical approaches. The fact that influenza remains an unsolved problem, in combination with the limitations of the conventional experimental models, motivated increasing attempts to use the power of other models, such as low eukaryotes, including invertebrate, and primary cell cultures. In this review, we summarized the efforts to study influenza in yeast, Drosophila, zebrafish and primary human tissue cultures and the major contributions these studies have made toward a better understanding of the disease. We feel that these models are still under-utilized and we highlight the unique potential each model has for better comprehending virus-host interactions and viral protein function.
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Affiliation(s)
- Sonja C J H Chua
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore.
- NUS Immunology Program, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.
- CREATE-NUS-HUJ Molecular Mechanisms of Inflammatory Diseases Programme, National University of Singapore, Singapore 138602, Singapore.
| | - Hui Qing Tan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore.
- NUS Immunology Program, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.
| | - David Engelberg
- CREATE-NUS-HUJ Molecular Mechanisms of Inflammatory Diseases Programme, National University of Singapore, Singapore 138602, Singapore.
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore.
- Department of Biological Chemistry, The Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Lina H K Lim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore.
- NUS Immunology Program, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.
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12
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Enhanced Replication of Mouse Adenovirus Type 1 following Virus-Induced Degradation of Protein Kinase R (PKR). mBio 2019; 10:mBio.00668-19. [PMID: 31015330 PMCID: PMC6479006 DOI: 10.1128/mbio.00668-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The first line of defense in cells during viral infection is the innate immune system, which is activated by different viral products. PKR is a part of this innate immune system and is induced by interferon and activated by dsRNA produced by DNA and RNA viruses. PKR is such an important part of the antiviral response that many viral families have gene products to counteract its activation or the resulting effects of its activity. Although a few RNA viruses degrade PKR, this method of counteracting PKR has not been reported for any DNA viruses. MAV-1 does not encode virus-associated RNAs, a human adenoviral defense against PKR activation. Instead, MAV-1 degrades PKR, and it is the first DNA virus reported to do so. The innate immune evasion by PKR degradation is a previously unidentified way for a DNA virus to circumvent the host antiviral response. Protein kinase R (PKR) plays a major role in activating host immunity during infection by sensing double-stranded RNA (dsRNA) produced by viruses. Once activated by dsRNA, PKR phosphorylates the translation factor eukaryotic initiation factor 2α (eIF2α), halting cellular translation. Many viruses have methods of inhibiting PKR activation or its downstream effects, circumventing protein synthesis shutdown. These include sequestering dsRNA or producing proteins that bind to and inhibit PKR activation. Here we describe our finding that in multiple cell types, PKR was depleted during mouse adenovirus type 1 (MAV-1) infection. MAV-1 did not appear to be targeting PKR at the transcriptional or translational level, because total PKR mRNA levels and levels of PKR mRNA bound to polysomes were unchanged or increased during MAV-1 infection. However, inhibiting the proteasome reduced the PKR depletion seen in MAV-1-infected cells, whereas inhibiting the lysosome had no effect. This suggests that proteasomal degradation alone is responsible for PKR degradation during MAV-1 infection. Time course experiments indicated that the degradation occurs early after infection. Infecting cells with UV-inactivated virus prevented PKR degradation, whereas inhibiting viral DNA replication did not. Together, these results suggest that an early viral gene is responsible. Degradation of PKR is a rare mechanism to oppose PKR activity, and it has been described in only six RNA viruses. To our knowledge, this is the first example of a DNA virus counteracting PKR by degrading it.
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13
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Marques M, Ramos B, Soares AR, Ribeiro D. Cellular Proteostasis During Influenza A Virus Infection-Friend or Foe? Cells 2019; 8:cells8030228. [PMID: 30857287 PMCID: PMC6468813 DOI: 10.3390/cells8030228] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/02/2019] [Accepted: 03/05/2019] [Indexed: 12/16/2022] Open
Abstract
In order to efficiently replicate, viruses require precise interactions with host components and often hijack the host cellular machinery for their own benefit. Several mechanisms involved in protein synthesis and processing are strongly affected and manipulated by viral infections. A better understanding of the interplay between viruses and their host-cell machinery will likely contribute to the development of novel antiviral strategies. Here, we discuss the current knowledge on the interactions between influenza A virus (IAV), the causative agent for most of the annual respiratory epidemics in humans, and the host cellular proteostasis machinery during infection. We focus on the manipulative capacity of this virus to usurp the cellular protein processing mechanisms and further review the protein quality control mechanisms in the cytosol and in the endoplasmic reticulum that are affected by this virus.
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Affiliation(s)
- Mariana Marques
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Bruno Ramos
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Ana Raquel Soares
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Daniela Ribeiro
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal.
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14
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Dzananovic E, McKenna SA, Patel TR. Viral proteins targeting host protein kinase R to evade an innate immune response: a mini review. Biotechnol Genet Eng Rev 2018; 34:33-59. [PMID: 29716441 DOI: 10.1080/02648725.2018.1467151] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The innate immune system offers a first line of defense by neutralizing foreign pathogens such as bacteria, fungi, and viruses. These pathogens express molecules (RNA and proteins) that have discrete structures, known as the pathogen-associated molecular patterns that are recognized by a highly specialized class of host proteins called pattern recognition receptors to facilitate the host's immune response against infection. The RNA-dependent Protein Kinase R (PKR) is one of the host's pattern recognition receptors that is a key component of an innate immune system. PKR recognizes imperfectly double-stranded non-coding viral RNA molecules via its N-terminal double-stranded RNA binding motifs, undergoes phosphorylation of the C-terminal kinase domain, ultimately resulting in inhibition of viral protein translation by inhibiting the guanine nucleotide exchange activity of eukaryotic initiation factor 2α. Not surprisingly, viruses have evolved mechanisms by which viral non-coding RNA or protein molecules inhibit PKR's activation and/or its downstream activity to allow viral replication. In this review, we will highlight the role of viral proteins in inhibiting PKR's activity and summarize currently known mechanisms by which viral proteins execute such inhibitory activity.
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Affiliation(s)
- Edis Dzananovic
- a Plant Pathology, Plant Protection and Molecular Biology , Agriculture and Agri-Food Canada , Saskatoon , Canada
| | - Sean A McKenna
- b Department of Chemistry, Manitoba Institute for Materials, Department of Biochemistry and Medical Genetics , University of Manitoba , Winnipeg , Canada
| | - Trushar R Patel
- c Department of Chemistry and Biochemistry , Alberta RNA Research and Training Institute, University of Lethbridge , Lethbridge , Canada.,d DiscoveryLab, Faculty of Medicine & Dentistry , University of Alberta , Edmonton , Canada.,e Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine , University of Calgary , Calgary , Canada
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15
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Zhao M, Wang L, Li S. Influenza A Virus-Host Protein Interactions Control Viral Pathogenesis. Int J Mol Sci 2017; 18:ijms18081673. [PMID: 28763020 PMCID: PMC5578063 DOI: 10.3390/ijms18081673] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 07/27/2017] [Accepted: 07/28/2017] [Indexed: 12/20/2022] Open
Abstract
The influenza A virus (IAV), a member of the Orthomyxoviridae family, is a highly transmissible respiratory pathogen and represents a continued threat to global health with considerable economic and social impact. IAV is a zoonotic virus that comprises a plethora of strains with different pathogenic profiles. The different outcomes of viral pathogenesis are dependent on the engagement between the virus and the host cellular protein interaction network. The interactions may facilitate virus hijacking of host molecular machinery to fulfill the viral life cycle or trigger host immune defense to eliminate the virus. In recent years, much effort has been made to discover the virus–host protein interactions and understand the underlying mechanisms. In this paper, we review the recent advances in our understanding of IAV–host interactions and how these interactions contribute to host defense and viral pathogenesis.
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Affiliation(s)
- Mengmeng Zhao
- 156 McElroy Hall, Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Lingyan Wang
- 156 McElroy Hall, Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Shitao Li
- 156 McElroy Hall, Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
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Influenza A Virus Virulence Depends on Two Amino Acids in the N-Terminal Domain of Its NS1 Protein To Facilitate Inhibition of the RNA-Dependent Protein Kinase PKR. J Virol 2017; 91:JVI.00198-17. [PMID: 28250123 DOI: 10.1128/jvi.00198-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 02/20/2017] [Indexed: 12/22/2022] Open
Abstract
The RNA-dependent protein kinase (PKR) has broad antiviral activity inducing translational shutdown of viral and cellular genes and is therefore targeted by various viral proteins to facilitate pathogen propagation. The pleiotropic NS1 protein of influenza A virus acts as silencer of PKR activation and ensures high-level viral replication and virulence. However, the exact manner of this inhibition remains controversial. To elucidate the structural requirements within the NS1 protein for PKR inhibition, we generated a set of mutant viruses, identifying highly conserved arginine residues 35 and 46 within the NS1 N terminus as being most critical not only for binding to and blocking activation of PKR but also for efficient virus propagation. Biochemical and Förster resonance energy transfer (FRET)-based interaction studies showed that mutation of R35 or R46 allowed formation of NS1 dimers but eliminated any detectable binding to PKR as well as to double-stranded RNA (dsRNA). Using in vitro and in vivo approaches to phenotypic restoration, we demonstrated the essential role of the NS1 N terminus for blocking PKR. The strong attenuation conferred by NS1 mutation R35A or R46A was substantially alleviated by stable knockdown of PKR in human cells. Intriguingly, both NS1 mutant viruses did not trigger any signs of disease in PKR+/+ mice, but replicated to high titers in lungs of PKR-/- mice and caused lethal infections. These data not only establish the NS1 N terminus as highly critical for neutralization of PKR's antiviral activity but also identify this blockade as an indispensable contribution of NS1 to the viral life cycle.IMPORTANCE Influenza A virus inhibits activation of the RNA-dependent protein kinase (PKR) by means of its nonstructural NS1 protein, but the underlying mode of inhibition is debated. Using mutational analysis, we identified arginine residues 35 and 46 within the N-terminal NS1 domain as highly critical for binding to and functional silencing of PKR. In addition, our data show that this is a main activity of amino acids 35 and 46, as the strong attenuation of corresponding mutant viruses in human cells was rescued to a large extent by lowering of PKR expression levels. Significantly, this corresponded with restoration of viral virulence for NS1 R35A and R46A mutant viruses in PKR-/- mice. Therefore, our data establish a model in which the NS1 N-terminal domain engages in a binding interaction to inhibit activation of PKR and ensure efficient viral propagation and virulence.
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Li T, Li X, Zhu W, Wang H, Mei L, Wu S, Lin X, Han X. NF90 is a novel influenza A virus NS1-interacting protein that antagonizes the inhibitory role of NS1 on PKR phosphorylation. FEBS Lett 2016; 590:2797-810. [PMID: 27423063 DOI: 10.1002/1873-3468.12311] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/01/2016] [Accepted: 07/06/2016] [Indexed: 12/24/2022]
Abstract
NF90 is a novel host antiviral factor that regulates PKR activation and stress granule formation in influenza A virus (IAV)-infected cells, but the precise mechanisms by which it operates remain unclear. We identified NF90 as a novel interacting protein of IAV nonstructural protein 1 (NS1). The interaction was dependent on the RNA-binding properties of NS1. NS1 associated with NF90 and PKR simultaneously; however, the interaction between NF90 and PKR was restricted by NS1. Knockdown of NF90 promoted inhibition of PKR phosphorylation induced by NS1, while coexpression of NF90 impeded reduction of PKR phosphorylation and stress granule formation triggered by NS1. In summary, NF90 exerts its antiviral activity by antagonizing the inhibitory role of NS1 on PKR phosphorylation.
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Affiliation(s)
- Ting Li
- Chinese Academy of Inspection and Quarantine, Institute of Animal Quarantine, Chaoyang District, Beijing, China
| | - Xi Li
- Chinese Academy of Inspection and Quarantine, Institute of Animal Quarantine, Chaoyang District, Beijing, China
| | - WenFei Zhu
- National Institute for Viral Disease Control and Prevention, Collaboration Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention; Key Laboratory for Medical Virology, National Health and Family Planning Commission, Beijing, China
| | - HuiYu Wang
- Chinese Academy of Inspection and Quarantine, Institute of Animal Quarantine, Chaoyang District, Beijing, China
| | - Lin Mei
- Chinese Academy of Inspection and Quarantine, Institute of Animal Quarantine, Chaoyang District, Beijing, China
| | - ShaoQiang Wu
- Chinese Academy of Inspection and Quarantine, Institute of Animal Quarantine, Chaoyang District, Beijing, China
| | - XiangMei Lin
- Chinese Academy of Inspection and Quarantine, Institute of Animal Quarantine, Chaoyang District, Beijing, China
| | - XueQing Han
- Chinese Academy of Inspection and Quarantine, Institute of Animal Quarantine, Chaoyang District, Beijing, China
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Zhao X, Tefsen B, Li Y, Qi J, Lu G, Shi Y, Yan J, Xiao H, Gao GF. The NS1 gene from bat-derived influenza-like virus H17N10 can be rescued in influenza A PR8 backbone. J Gen Virol 2016; 97:1797-1806. [DOI: 10.1099/jgv.0.000509] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Xuejin Zhao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Boris Tefsen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University, No 111, Ren Ai Road, Dushu Lake Higher Education Town, Suzhou Industrial Park (SIP), Suzhou 215123, P. R. China
| | - Yan Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Jianxun Qi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Guangwen Lu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Yi Shi
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
- Beijing Institute of Life Science, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Jinghua Yan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Haixia Xiao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - George F. Gao
- Beijing Institute of Life Science, Chinese Academy of Sciences, Beijing 100101, P. R. China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing 100101, P. R. China
- Office of Director-General, Chinese Center for Disease Control and Prevention, Beijing 102206, P. R. China
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
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Esmagambetov IB, Alekseeva SV, Sayadyan KS, Shmarov MM. CURRENT APPROACHES TO UNIVERSAL VACCINE AGAINST INFLUENZA VIRUS. RUSSIAN JOURNAL OF INFECTION AND IMMUNITY 2016. [DOI: 10.15789/2220-7619-2016-2-117-132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Qin Z, Yang Y, Wang H, Luo J, Huang X, You J, Wang B, Li M. Role of Autophagy and Apoptosis in the Postinfluenza Bacterial Pneumonia. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3801026. [PMID: 27376082 PMCID: PMC4916274 DOI: 10.1155/2016/3801026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/05/2016] [Accepted: 05/16/2016] [Indexed: 12/19/2022]
Abstract
The risk of influenza A virus (IAV) is more likely caused by secondary bacterial infections. During the past decades, a great amount of studies have been conducted on increased morbidity from secondary bacterial infections following influenza and provide an increasing number of explanations for the mechanisms underlying the infections. In this paper, we first review the recent research progress that IAV infection increased susceptibility to bacterial infection. We then propose an assumption that autophagy and apoptosis manipulation are beneficial to antagonize post-IAV bacterial infection and discuss the clinical significance.
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Affiliation(s)
- Zhen Qin
- Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Yuan Yang
- Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Hongren Wang
- Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Jun Luo
- Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Xiaojun Huang
- Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Jiangzhou You
- Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Baoning Wang
- Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Mingyuan Li
- Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, Sichuan 610041, China
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Li F, Chen Y, Zhang Z, Ouyang J, Wang Y, Yan R, Huang S, Gao GF, Guo G, Chen JL. Robust expression of vault RNAs induced by influenza A virus plays a critical role in suppression of PKR-mediated innate immunity. Nucleic Acids Res 2015; 43:10321-37. [PMID: 26490959 PMCID: PMC4666359 DOI: 10.1093/nar/gkv1078] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/07/2015] [Indexed: 12/29/2022] Open
Abstract
Protein kinase R (PKR) is a vital component of host innate immunity against viral infection. However, the mechanism underlying inactivation of PKR by influenza A virus (IAV) remains elusive. Here, we found that vault RNAs (vtRNAs) were greatly induced in A549 cells and mouse lungs after infection with IAV. The viral NS1 protein was shown to be the inducer triggering the upregulation of vtRNAs. Importantly, silencing vtRNA in A549 cells significantly inhibited IAV replication, whereas overexpression of vtRNAs markedly promoted the viral replication. Furthermore, in vivo studies showed that disrupting vtRNA expression in mice significantly decreased IAV replication in infected lungs. The vtRNA knockdown animals exhibited significantly enhanced resistance to IAV infection, as evidenced by attenuated acute lung injury and spleen atrophy and consequently increased survival rates. Interestingly, vtRNAs promoted viral replication through repressing the activation of PKR and the subsequent antiviral interferon response. In addition, increased expression of vtRNAs was required for efficient suppression of PKR by NS1 during IAV infection. Moreover, vtRNAs were also significantly upregulated by infections of several other viruses and involved in the inactivation of PKR signaling by these viruses. These results reveal a novel mechanism by which some viruses circumvent PKR-mediated innate immunity.
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Affiliation(s)
- Fang Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Yuhai Chen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Zhaoyuan Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China School of Life Sciences, Anhui University, Hefei 230601, China
| | - Jing Ouyang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Yi Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Ruoxiang Yan
- College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shile Huang
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - George Fu Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Guijie Guo
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Ji-Long Chen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Timing Is Everything: Coordinated Control of Host Shutoff by Influenza A Virus NS1 and PA-X Proteins. J Virol 2015; 89:6528-31. [PMID: 25878098 DOI: 10.1128/jvi.00386-15] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Like all viruses, influenza viruses (IAVs) use host translation machinery to decode viral mRNAs. IAVs ensure efficient translation of viral mRNAs through host shutoff, a process whereby viral proteins limit the accumulation of host proteins through subversion of their biogenesis. Despite its small genome, the virus deploys multiple host shutoff mechanisms at different stages of infection, thereby ensuring successful replication while limiting the communication of host antiviral responses. In this Gem, we review recent data on IAV host shutoff proteins, frame the outstanding questions in the field, and propose a temporally coordinated model of IAV host shutoff.
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Ranjan P, Singh N, Kumar A, Neerincx A, Kremmer E, Cao W, Davis WG, Katz JM, Gangappa S, Lin R, Kufer TA, Sambhara S. NLRC5 interacts with RIG-I to induce a robust antiviral response against influenza virus infection. Eur J Immunol 2015; 45:758-72. [PMID: 25404059 DOI: 10.1002/eji.201344412] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 10/15/2014] [Accepted: 11/13/2014] [Indexed: 12/16/2023]
Abstract
The NLR protein, NLRC5 is an important regulator of MHC class I gene expression, however, the role of NLRC5 in other innate immune responses is less well defined. In the present study, we report that NLRC5 binds RIG-I and that this interaction is critical for robust antiviral responses against influenza virus. Overexpression of NLRC5 in the human lung epithelial cell line, A549, and normal human bronchial epithelial cells resulted in impaired replication of influenza virus A/Puerto Rico/8/34 virus (PR8) and enhanced IFN-β expression. Influenza virus leads to induction of IFN-β that drives RIG-I and NLRC5 expression in host cells. Our results suggest that NLRC5 extends and stabilizes influenza virus induced RIG-I expression and delays expression of the viral inhibitor protein NS1. We show that NS1 binds to NLRC5 to suppress its function. Interaction domain mapping revealed that NLRC5 interacts with RIG-I via its N-terminal death domain and that NLRC5 enhanced antiviral activity in an leucine-rich repeat domain independent manner. Taken together, our findings identify a novel role for NLRC5 in RIG-I-mediated antiviral host responses against influenza virus infection, distinguished from the role of NLRC5 in MHC class I gene regulation.
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Affiliation(s)
- Priya Ranjan
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Tawaratsumida K, Phan V, Hrincius ER, High AA, Webby R, Redecke V, Häcker H. Quantitative proteomic analysis of the influenza A virus nonstructural proteins NS1 and NS2 during natural cell infection identifies PACT as an NS1 target protein and antiviral host factor. J Virol 2014; 88:9038-48. [PMID: 24899174 PMCID: PMC4136281 DOI: 10.1128/jvi.00830-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 05/24/2014] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Influenza A virus (IAV) replication depends on the interaction of virus proteins with host factors. The viral nonstructural protein 1 (NS1) is essential in this process by targeting diverse cellular functions, including mRNA splicing and translation, cell survival, and immune defense, in particular the type I interferon (IFN-I) response. In order to identify host proteins targeted by NS1, we established a replication-competent recombinant IAV that expresses epitope-tagged forms of NS1 and NS2, which are encoded by the same gene segment, allowing purification of NS proteins during natural cell infection and analysis of interacting proteins by quantitative mass spectrometry. We identified known NS1- and NS2-interacting proteins but also uncharacterized proteins, including PACT, an important cofactor for the IFN-I response triggered by the viral RNA-sensor RIG-I. We show here that NS1 binds PACT during virus replication and blocks PACT/RIG-I-mediated activation of IFN-I, which represents a critical event for the host defense. Protein interaction and interference with IFN-I activation depended on the functional integrity of the highly conserved RNA binding domain of NS1. A mutant virus with deletion of NS1 induced high levels of IFN-I in control cells, as expected; in contrast, shRNA-mediated knockdown of PACT compromised IFN-I activation by the mutant virus, but not wild-type virus, a finding consistent with the interpretation that PACT (i) is essential for IAV recognition and (ii) is functionally compromised by NS1. Together, our data describe a novel approach to identify virus-host protein interactions and demonstrate that NS1 interferes with PACT, whose function is critical for robust IFN-I production. IMPORTANCE Influenza A virus (IAV) is an important human pathogen that is responsible for annual epidemics and occasional devastating pandemics. Viral replication and pathogenicity depends on the interference of viral factors with components of the host defense system, particularly the type I interferon (IFN-I) response. The viral NS1 protein is known to counteract virus recognition and IFN-I production, but the molecular mechanism is only partially defined. We used a novel proteomic approach to identify host proteins that are bound by NS1 during virus replication and identified the protein PACT, which had previously been shown to be involved in virus-mediated IFN-I activation. We find that NS1 prevents PACT from interacting with an essential component of the virus recognition pathway, RIG-I, thereby disabling efficient IFN-I production. These observations provide an important piece of information on how IAV efficiently counteracts the host immune defense.
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Affiliation(s)
- Kazuki Tawaratsumida
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Van Phan
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Eike R Hrincius
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Anthony A High
- Proteomics Core Facility, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Richard Webby
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Vanessa Redecke
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Hans Häcker
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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Forbes N, Selman M, Pelchat M, Jia JJ, Stintzi A, Brown EG. Identification of adaptive mutations in the influenza A virus non-structural 1 gene that increase cytoplasmic localization and differentially regulate host gene expression. PLoS One 2013; 8:e84673. [PMID: 24391972 PMCID: PMC3877356 DOI: 10.1371/journal.pone.0084673] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 11/18/2013] [Indexed: 12/22/2022] Open
Abstract
The NS1 protein of influenza A virus (IAV) is a multifunctional virulence factor. We have previously characterized gain-of-function mutations in the NS1 protein arising from the experimental adaptation of the human isolate A/Hong Kong/1/1968(H3N2) (HK) to the mouse. The majority of these mouse adapted NS1 mutations were demonstrated to increase virulence, viral fitness, and interferon antagonism, but differ in binding to the post-transcriptional processing factor cleavage and polyadenylation specificity factor 30 (CPSF30). Because nuclear trafficking is a major genetic determinant of influenza virus host adaptation, we assessed subcellular localization and host gene expression of NS1 adaptive mutations. Recombinant HK viruses with adaptive mutations in the NS1 gene were assessed for NS1 protein subcellular localization in mouse and human cells using confocal microscopy and cellular fractionation. In human cells the HK wild-type (HK-wt) virus NS1 protein partitioned equivalently between the cytoplasm and nucleus but was defective in cytoplasmic localization in mouse cells. Several adaptive mutations increased the proportion of NS1 in the cytoplasm of mouse cells with the greatest effects for mutations M106I and D125G. The host gene expression profile of the adaptive mutants was determined by microarray analysis of infected mouse cells to show either high or low extents of host-gene regulation (HGR or LGR) phenotypes. While host genes were predominantly down regulated for the HGR group of mutants (D2N, V23A, F103L, M106I+L98S, L98S, M106V, and M106V+M124I), the LGR phenotype mutants (D125G, M106I, V180A, V226I, and R227K) were characterized by a predominant up regulation of host genes. CPSF30 binding affinity of NS1 mutants did not predict effects on host gene expression. To our knowledge this is the first report of roles of adaptive NS1 mutations that impact intracellular localization and regulation of host gene expression.
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Affiliation(s)
- Nicole Forbes
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Emerging Pathogens Research Centre, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Mohammed Selman
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Emerging Pathogens Research Centre, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Martin Pelchat
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Jian Jun Jia
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Alain Stintzi
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Earl G. Brown
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Emerging Pathogens Research Centre, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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Ozaki H, Kida H. Extensive Accumulation of Influenza Virus NS1 Protein in the Nuclei Causes Effective Viral Growth in Vero Cells. Microbiol Immunol 2013; 51:577-80. [PMID: 17579268 DOI: 10.1111/j.1348-0421.2007.tb03935.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We previously showed that modified A/Puerto Rico/8/34 (PR8) influenza master strain had improved viral rescue and growth properties in African green monkey kidney (Vero) cell line by introducing NS gene of Vero-adapted A/England/1/53 (vaEng53). In the present study, it was found that the NS1 protein derived from vaEng53 was extensively accumulated in the nuclei than that of PR8. This accumulation was caused by 7 amino acid differences in C-terminal region of NS1 protein. These results suggest that specific accumulation of NS1 protein may contribute to efficient viral replication in Vero cells.
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Affiliation(s)
- Hiroichi Ozaki
- Creative Research Initiative Sousei, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan.
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Matsuoka Y, Matsumae H, Katoh M, Eisfeld AJ, Neumann G, Hase T, Ghosh S, Shoemaker JE, Lopes TJS, Watanabe T, Watanabe S, Fukuyama S, Kitano H, Kawaoka Y. A comprehensive map of the influenza A virus replication cycle. BMC SYSTEMS BIOLOGY 2013; 7:97. [PMID: 24088197 PMCID: PMC3819658 DOI: 10.1186/1752-0509-7-97] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 09/24/2013] [Indexed: 02/05/2023]
Abstract
Background Influenza is a common infectious disease caused by influenza viruses. Annual epidemics cause severe illnesses, deaths, and economic loss around the world. To better defend against influenza viral infection, it is essential to understand its mechanisms and associated host responses. Many studies have been conducted to elucidate these mechanisms, however, the overall picture remains incompletely understood. A systematic understanding of influenza viral infection in host cells is needed to facilitate the identification of influential host response mechanisms and potential drug targets. Description We constructed a comprehensive map of the influenza A virus (‘IAV’) life cycle (‘FluMap’) by undertaking a literature-based, manual curation approach. Based on information obtained from publicly available pathway databases, updated with literature-based information and input from expert virologists and immunologists, FluMap is currently composed of 960 factors (i.e., proteins, mRNAs etc.) and 456 reactions, and is annotated with ~500 papers and curation comments. In addition to detailing the type of molecular interactions, isolate/strain specific data are also available. The FluMap was built with the pathway editor CellDesigner in standard SBML (Systems Biology Markup Language) format and visualized as an SBGN (Systems Biology Graphical Notation) diagram. It is also available as a web service (online map) based on the iPathways+ system to enable community discussion by influenza researchers. We also demonstrate computational network analyses to identify targets using the FluMap. Conclusion The FluMap is a comprehensive pathway map that can serve as a graphically presented knowledge-base and as a platform to analyze functional interactions between IAV and host factors. Publicly available webtools will allow continuous updating to ensure the most reliable representation of the host-virus interaction network. The FluMap is available at http://www.influenza-x.org/flumap/.
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Affiliation(s)
- Yukiko Matsuoka
- JST ERATO Kawaoka infection-induced host responses project, Minato-ku, Tokyo 108-8639, Japan.
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Liedmann S, Hrincius ER, Anhlan D, McCullers JA, Ludwig S, Ehrhardt C. New virulence determinants contribute to the enhanced immune response and reduced virulence of an influenza A virus A/PR8/34 variant. J Infect Dis 2013; 209:532-41. [PMID: 23983213 DOI: 10.1093/infdis/jit463] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The identification of amino acid motifs responsible for increased virulence and/or transmission of influenza viruses is of enormous importance to predict pathogenicity of upcoming influenza strains. We phenotypically and genotypically compared 2 variants of influenza virus A/PR/8/34 with different passage histories. The analysis revealed differences in virulence due to an altered type I interferon (IFN) induction, as evidenced by experiments using IFNAR(-/-) mice. Interestingly, these differences were not due to altered functions of the well-known viral IFN antagonists NS1 or PB1-F2. Using reassortant viruses, we showed that differences in the polymerase proteins and nucleoprotein determined the altered virulence. In particular, changes in PB1 and PA contributed to an altered host type I IFN response, indicating IFN antagonistic properties of these proteins. Thus, PB1 and PA appear to harbor previously unknown virulence markers, which may prove helpful in assessing the risk potential of emerging influenza viruses.
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Affiliation(s)
- Swantje Liedmann
- Institute of Molecular Virology, Center for Molecular Biology of Inflammation, University of Muenster, Germany
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29
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de Chassey B, Aublin-Gex A, Ruggieri A, Meyniel-Schicklin L, Pradezynski F, Davoust N, Chantier T, Tafforeau L, Mangeot PE, Ciancia C, Perrin-Cocon L, Bartenschlager R, André P, Lotteau V. The interactomes of influenza virus NS1 and NS2 proteins identify new host factors and provide insights for ADAR1 playing a supportive role in virus replication. PLoS Pathog 2013; 9:e1003440. [PMID: 23853584 PMCID: PMC3701712 DOI: 10.1371/journal.ppat.1003440] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 05/06/2013] [Indexed: 12/24/2022] Open
Abstract
Influenza A NS1 and NS2 proteins are encoded by the RNA segment 8 of the viral genome. NS1 is a multifunctional protein and a virulence factor while NS2 is involved in nuclear export of viral ribonucleoprotein complexes. A yeast two-hybrid screening strategy was used to identify host factors supporting NS1 and NS2 functions. More than 560 interactions between 79 cellular proteins and NS1 and NS2 proteins from 9 different influenza virus strains have been identified. These interacting proteins are potentially involved in each step of the infectious process and their contribution to viral replication was tested by RNA interference. Validation of the relevance of these host cell proteins for the viral replication cycle revealed that 7 of the 79 NS1 and/or NS2-interacting proteins positively or negatively controlled virus replication. One of the main factors targeted by NS1 of all virus strains was double-stranded RNA binding domain protein family. In particular, adenosine deaminase acting on RNA 1 (ADAR1) appeared as a pro-viral host factor whose expression is necessary for optimal viral protein synthesis and replication. Surprisingly, ADAR1 also appeared as a pro-viral host factor for dengue virus replication and directly interacted with the viral NS3 protein. ADAR1 editing activity was enhanced by both viruses through dengue virus NS3 and influenza virus NS1 proteins, suggesting a similar virus-host co-evolution. Viruses are obligate intracellular parasites that rely on cellular functions for efficient replication. As most biological processes are sustained by protein-protein interactions, the identification of interactions between viral and host proteins can provide a global overview about the cellular functions engaged during viral replication. Influenza viruses express 13 viral proteins, including NS1 and NS2, which are translated from an alternatively spliced RNA derived from the same genome segment. We present here a comprehensive overview of possible interactions of cellular proteins with NS1 and NS2 from 9 viral strains. Seventy nine cellular proteins were identified to interact with NS1, NS2 or both NS1 and NS2. These interacting host cell proteins are potentially involved in many steps of the virus life cycle and 7 can directly control the viral replication. Most of the cellular targets are shared by the majority of the virus strains, especially the double-stranded RNA binding domain protein family that is strikingly targeted by NS1. One of its members, ADAR1, is essential for influenza virus replication. ADAR1 colocalizes with NS1 in nuclear structures and its editing activity is enhanced by NS1 expressed on its own and during virus infection. A similar phenomenon is observed for dengue virus whose NS3 protein also interacts with ADAR1, suggesting a parallel virus-host co-evolution.
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Affiliation(s)
- Benoît de Chassey
- Hospices Civils de Lyon, Hôpital de la Croix Rousse, Laboratory of Virology, Lyon, France
| | - Anne Aublin-Gex
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Alessia Ruggieri
- Department for Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Laurène Meyniel-Schicklin
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Fabrine Pradezynski
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Nathalie Davoust
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Thibault Chantier
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Lionel Tafforeau
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Philippe-Emmanuel Mangeot
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Claire Ciancia
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Laure Perrin-Cocon
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Ralf Bartenschlager
- Department for Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Patrice André
- Hospices Civils de Lyon, Hôpital de la Croix Rousse, Laboratory of Virology, Lyon, France
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
| | - Vincent Lotteau
- CIRI, International Center for Infectiology Research, EVIR Team, Université de Lyon, Lyon, France
- Inserm, U1111, Lyon, France
- Ecole Normale Supérieure de Lyon, Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France
- CNRS, UMR5308, Lyon, France
- * E-mail:
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Bierle CJ, Semmens KM, Geballe AP. Double-stranded RNA binding by the human cytomegalovirus PKR antagonist TRS1. Virology 2013; 442:28-37. [PMID: 23601785 DOI: 10.1016/j.virol.2013.03.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 02/15/2013] [Accepted: 03/25/2013] [Indexed: 02/02/2023]
Abstract
Protein Kinase R (PKR) inhibits translation initiation following double-stranded RNA (dsRNA) binding and thereby represses viral replication. Human cytomegalovirus (HCMV) encodes two noncanonical dsRNA binding proteins, IRS1 and TRS1, and the expression of at least one of these PKR antagonists is essential for HCMV replication. In this study, we investigated the role of dsRNA binding by TRS1 in PKR inhibition. We found that purified TRS1 binds specifically to dsRNA with an affinity lower than that of PKR. Point mutants in the TRS1 dsRNA binding domain that were deficient in rescuing the replication of vaccinia virus lacking its PKR antagonist E3L were unable to bind to dsRNA but retained the ability bind to PKR. Thus TRS1 binding to dsRNA and to PKR are separable. Overall, our results are most consistent with a model in which TRS1 binds simultaneously to both dsRNA and PKR to inhibit PKR activation.
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Affiliation(s)
- Craig J Bierle
- Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98115, United States.
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31
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Abstract
Avian influenza virus infections in the human population are rare due to their inefficient direct human-to-human transmission. However, when humans are infected, a strong inflammatory response is usually induced, characterized by elevated levels of cytokines and chemokines in serum, believed to be important in the severe pathogenesis that develops in a high proportion of these patients. Extensive research has been performed to understand the molecular viral mechanisms involved in the H5N1 pathogenesis in humans, providing interesting insights about the virus-host interaction and the regulation of the innate immune response by these highly pathogenic viruses. In this review we summarize and discuss the most important findings in this field, focusing mainly on H5N1 virulence factors and their impact on the modulation of the innate immunity in humans.
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Affiliation(s)
- Irene Ramos
- Authors to whom correspondence should be addressed; (A.F.S.); (I.R.); Tel. +1-212-241-5182 (A.F.S.); +1-212 241-0994 (I.R.); Fax: +1-212-534-1684 (A.F.S.); +1-212-534-1684 (I.R.)
| | - Ana Fernandez-Sesma
- Authors to whom correspondence should be addressed; (A.F.S.); (I.R.); Tel. +1-212-241-5182 (A.F.S.); +1-212 241-0994 (I.R.); Fax: +1-212-534-1684 (A.F.S.); +1-212-534-1684 (I.R.)
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SUMOylation affects the interferon blocking activity of the influenza A nonstructural protein NS1 without affecting its stability or cellular localization. J Virol 2013; 87:5602-20. [PMID: 23468495 DOI: 10.1128/jvi.02063-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our pioneering studies on the interplay between the small ubiquitin-like modifier (SUMO) and influenza A virus identified the nonstructural protein NS1 as the first known SUMO target of influenza virus and one of the most abundantly SUMOylated influenza virus proteins. Here, we further characterize the role of SUMOylation for the A/Puerto Rico/8/1934 (PR8) NS1 protein, demonstrating that NS1 is SUMOylated not only by SUMO1 but also by SUMO2/3 and mapping the main SUMOylation sites in NS1 to residues K219 and K70. Furthermore, by using SUMOylatable and non-SUMOylatable forms of NS1 and an NS1-specific artificial SUMO ligase (ASL) that increases NS1 SUMOylation ~4-fold, we demonstrate that SUMOylation does not affect the stability or cellular localization of PR8 NS1. However, NS1's ability to be SUMOylated appears to affect virus multiplication, as indicated by the delayed growth of a virus expressing the non-SUMOylatable form of NS1 in the interferon (IFN)-competent MDCK cell line. Remarkably, while a non-SUMOylatable form of NS1 exhibited a substantially diminished ability to neutralize IFN production, increasing NS1 SUMOylation beyond its normal levels also exerted a negative effect on its IFN-blocking function. This observation indicates the existence of an optimal level of NS1 SUMOylation that allows NS1 to achieve maximal activity and suggests that the limited amount of SUMOylation normally observed for most SUMO targets may correspond to an optimal level that maximizes the contribution of SUMOylation to protein function. Finally, protein cross-linking data suggest that SUMOylation may affect NS1 function by regulating the abundance of NS1 dimers and trimers in the cell.
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33
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Contribution of double-stranded RNA and CPSF30 binding domains of influenza virus NS1 to the inhibition of type I interferon production and activation of human dendritic cells. J Virol 2012; 87:2430-40. [PMID: 23255794 DOI: 10.1128/jvi.02247-12] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The influenza virus nonstructural protein 1 (NS1) inhibits innate immunity by multiple mechanisms. We previously reported that NS1 is able to inhibit the production of type I interferon (IFN) and proinflammatory cytokines in human primary dendritic cells (DCs). Here, we used recombinant viruses expressing mutant NS1 from the A/Texas/36/91 and A/Puerto Rico/08/34 strains in order to analyze the contribution of different NS1 domains to its antagonist functions. We show that the polyadenylation stimulating factor 30 (CPSF30) binding function of the NS1 protein from A/Texas/36/91 influenza virus, which is absent in the A/Puerto Rico/08/34 strain, is essential for counteracting these innate immune events in DCs. However, the double-stranded RNA (dsRNA) binding domain, present in both strains, specifically inhibits the induction of type I IFN genes in infected DCs, while it is essential only for inhibition of type I IFN proteins and proinflammatory cytokine production in cells infected with influenza viruses lacking a functional CPSF30 binding domain, such as A/Puerto Rico/08/34.
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34
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Han X, Li Z, Chen H, Wang H, Mei L, Wu S, Zhang T, Liu B, Lin X. Influenza virus A/Beijing/501/2009(H1N1) NS1 interacts with β-tubulin and induces disruption of the microtubule network and apoptosis on A549 cells. PLoS One 2012; 7:e48340. [PMID: 23139776 PMCID: PMC3491056 DOI: 10.1371/journal.pone.0048340] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 09/24/2012] [Indexed: 11/18/2022] Open
Abstract
NS1 of influenza A virus is a key multifunctional protein that plays various roles in regulating viral replication mechanisms, host innate/adaptive immune responses, and cellular signalling pathways. These functions rely on its ability to participate in a multitude of protein-protein and protein-RNA interactions. To gain further insight into the role of NS1, a tandem affinity purification (TAP) method was utilized to find unknown interaction partner of NS1. The protein complexes of NS1 and its interacting partner were purified from A549 cell using TAP-tagged NS1 as bait, and co-purified cellular factors were identified by mass spectrometry (MS). We identified cellular β-tubulin as a novel interaction partner of NS1. The RNA-binding domain of NS1 interacts with β-tubulin through its RNA-binding domain, as judged by a glutathione S-transferase (GST) pull-down assay with the GST-fused functional domains of NS1. Immunofluorescence analysis further revealed that NS1 with β-tubulin co-localized in the nucleus. In addition, the disruption of the microtubule network and apoptosis were also observed on NS1-transfected A549 cells. Our findings suggest that influenza A virus may utilize its NS1 protein to interact with cellular β-tubulin to further disrupt normal cell division and induce apoptosis. Future work will illustrate whether this interaction is uniquely specific to the 2009 pandemic H1N1 virus.
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Affiliation(s)
- Xueqing Han
- Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Zhihui Li
- Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Hongjun Chen
- Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Huiyu Wang
- Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Lin Mei
- Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Shaoqiang Wu
- Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Tianyi Zhang
- College of Veterinary Medicine, China Agricultural University, Bejing, China
| | - Bohua Liu
- State Key Laboratory of Pathogens and Bio-security, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- * E-mail: (XL); (BL)
| | - Xiangmei Lin
- Chinese Academy of Inspection and Quarantine, Beijing, China
- * E-mail: (XL); (BL)
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The infectious bursal disease virus RNA-binding VP3 polypeptide inhibits PKR-mediated apoptosis. PLoS One 2012; 7:e46768. [PMID: 23056444 PMCID: PMC3467284 DOI: 10.1371/journal.pone.0046768] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 09/05/2012] [Indexed: 01/07/2023] Open
Abstract
Infectious bursal disease virus (IBDV) is an avian pathogen responsible for an acute immunosuppressive disease that causes major losses to the poultry industry. Despite having a bipartite dsRNA genome, IBDV, as well as other members of the Birnaviridae family, possesses a single capsid layer formed by trimers of the VP2 capsid protein. The capsid encloses a ribonucleoprotein complex formed by the genome associated to the RNA-dependent RNA polymerase and the RNA-binding polypeptide VP3. A previous report evidenced that expression of the mature VP2 IBDV capsid polypeptide triggers a swift programmed cell death response in a wide variety of cell lines. The mechanism(s) underlying this effect remained unknown. Here, we show that VP2 expression in HeLa cells activates the double-stranded RNA (dsRNA)-dependent protein kinase (PKR), which in turn triggers the phosphorylation of the eukaryotic initiation factor 2α (eIF2α). This results in a strong blockade of protein synthesis and the activation of an apoptotic response which is efficiently blocked by coexpression of a dominant negative PKR polypeptide. Our results demonstrate that coexpression of the VP3 polypeptide precludes phosphorylation of both PKR and eIF2α and the onset of programmed cell death induced by VP2 expression. A mutation blocking the capacity of VP3 to bind dsRNA also abolishes its capacity to prevent PKR activation and apoptosis. Further experiments showed that VP3 functionally replaces the host-range vaccinia virus (VACV) E3 protein, thus allowing the E3 deficient VACV deletion mutant WRΔE3L to grow in non-permissive cell lines. According to results presented here, VP3 can be categorized along with other well characterized proteins such us VACV E3, avian reovirus sigmaA, and influenza virus NS1 as a virus-encoded dsRNA-binding polypeptide with antiapoptotic properties. Our results suggest that VP3 plays a central role in ensuring the viability of the IBDV replication cycle by preventing programmed cell death.
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36
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Mi Z, Ma Y, Tong Y. Avian influenza virus H5N1 induces rapid interferon-beta production but shows more potent inhibition to retinoic acid-inducible gene I expression than H1N1 in vitro. Virol J 2012; 9:145. [PMID: 22862800 PMCID: PMC3464129 DOI: 10.1186/1743-422x-9-145] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 07/30/2012] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The mechanisms through which the avian influenza virus H5N1 modulate the host's innate immune defense during invasion, remains incompletely understood. RIG-I as a pattern recognition receptor plays an important role in mediating innate immune response induced by influenza virus. So, modulating RIG-I might be adopted as a strategy by influenza virus to antagonize the host's innate immune defense. METHODS Here we chose an avian influenza virus A/tree sparrow/Henan/1/04 (H5N1) directly isolated from a free-living tree sparrow in Mainland China which is amplified in egg allantoic cavity, and researched its interferon induction and manipulation of RIG-I expression compared with influenza virus A/WSN/1933(H1N1), a well characterized mouse adapted strain, in human lung epithelial A549 cells and human embryonic kidney 293T cells. RESULTS Although the avian influenza virus H5N1 infection initiated a rapid IFN-beta production early on, it eventually presented a more potent inhibition to IFN-beta production than H1N1. Correspondingly, the H5N1 infection induced low level expression of endogenous RIG-I, an Interferon Stimulating Gene (ISG), and showed more potent inhibition to the expression of endogenous RIG-I triggered by exogenous interferon than H1N1. CONCLUSIONS Manipulating endogenous RIG-I expression might constitute one of the mechanisms through which avian influenza virus H5N1 control the host's innate immune response during infection.
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Affiliation(s)
- Zhiqiang Mi
- Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Beijing, Fengtai District, 100071, China
| | - Yonghong Ma
- Center for Disease Control and Prevention in Xinjiang Military Command, Xinjiang Uygur Autonomous Region, Xinjiang Uygur, 830000, China
| | - Yigang Tong
- Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Beijing, Fengtai District, 100071, China
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Hrincius ER, Hennecke AK, Gensler L, Nordhoff C, Anhlan D, Vogel P, McCullers JA, Ludwig S, Ehrhardt C. A Single Point Mutation (Y89F) within the Non-Structural Protein 1 of Influenza A Viruses Limits Epithelial Cell Tropism and Virulence in Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:2361-74. [DOI: 10.1016/j.ajpath.2012.02.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 02/22/2012] [Accepted: 02/28/2012] [Indexed: 12/15/2022]
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38
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Leung DW, Basler CF, Amarasinghe GK. Molecular mechanisms of viral inhibitors of RIG-I-like receptors. Trends Microbiol 2012; 20:139-46. [PMID: 22325030 DOI: 10.1016/j.tim.2011.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 12/19/2011] [Accepted: 12/23/2011] [Indexed: 12/25/2022]
Abstract
Activation of innate immune signaling pathways through cytosolic RIG-I-like receptors (RLR) is a crucial response that is antagonized by many viruses. A variety of RNA-related pathogen-associated molecular patterns (PAMPS) have been identified and their role in RLR activation has been examined. Recent studies suggest that several virus-encoded components that antagonize RLR signaling interact with and inhibit the interferon (IFN)-α/β activation pathway using both RNA-dependent and RNA-independent mechanisms. The structural basis for these RLR inhibitory mechanisms, as well as the multifunctional nature of viral RLR antagonists, is reviewed in the context of recent biochemical and structural studies.
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Affiliation(s)
- Daisy W Leung
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA.
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Guerra S, Abaitua F, Martínez-Sobrido L, Esteban M, García-Sastre A, Rodríguez D. Host-range restriction of vaccinia virus E3L deletion mutant can be overcome in vitro, but not in vivo, by expression of the influenza virus NS1 protein. PLoS One 2011; 6:e28677. [PMID: 22174864 PMCID: PMC3236761 DOI: 10.1371/journal.pone.0028677] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 11/13/2011] [Indexed: 12/18/2022] Open
Abstract
During the last decades, research focused on vaccinia virus (VACV) pathogenesis has been intensified prompted by its potential beneficial application as a vector for vaccine development and anti-cancer therapies, but also due to the fear of its potential use as a bio-terrorism threat. Recombinant viruses lacking a type I interferon (IFN) antagonist are attenuated and hence good vaccine candidates. However, vaccine virus growth requires production in IFN-deficient systems, and thus viral IFN antagonists that are active in vitro, yet not in vivo, are of great value. The VACV E3 and influenza virus NS1 proteins are distinct double-stranded RNA-binding proteins that play an important role in pathogenesis by inhibiting the mammalian IFN-regulated innate antiviral response. Based on the functional similarities between E3 and NS1, we investigated the ability of NS1 to replace the biological functions of E3 of VACV in both in vitro and in vivo systems. For this, we generated a VACV recombinant virus lacking the E3L gene, yet expressing NS1 (VVΔE3L/NS1). Our study revealed that NS1 can functionally replace E3 in cultured cells, rescuing the protein synthesis blockade, and preventing apoptosis and RNA breakdown. In contrast, in vivo the VVΔE3L/NS1 virus was highly attenuated after intranasal inoculation, as it was unable to spread to the lungs and other organs. These results indicate that there are commonalities but also functional differences in the roles of NS1 and E3 as inhibitors of the innate antiviral response, which could potentially be utilized for vaccine production purposes in the future.
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Affiliation(s)
- Susana Guerra
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- Department of Preventive Medicine and Public Health, Universidad Autónoma, Madrid, Spain
- * E-mail: (SG); (DR)
| | - Fernando Abaitua
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Luis Martínez-Sobrido
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Mariano Esteban
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Adolfo García-Sastre
- Department of Microbiology, Mount Sinai School of Medicine, New York, New York, United States of America
- Division of Infectious Diseases, Department of Medicine, Mount Sinai School of Medicine, New York, New York, United States of America
- Global Health and Emerging Pathogens Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Dolores Rodríguez
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- * E-mail: (SG); (DR)
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Wang Y, Zhou J, Ruan C, Du Y. Inhibition of type I interferon production via suppressing IKK-gamma expression: a new strategy for counteracting host antiviral defense by influenza A viruses? J Proteome Res 2011; 11:217-23. [PMID: 22054014 DOI: 10.1021/pr200894t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Blockage of the induction of type I interferons (IFNs) is essential for the success of influenza virus proliferation in host cells. Several molecular mechanisms by which influenza viruses inhibit IFN induction have been characterized. Here we report a potentially new strategy influenza viruses employ to inhibit IFN production during viral infection. Through a two-dimensional gel electrophoresis based proteomic approach, we found that the expression of IκB kinase-gamma (IKKγ) was suppressed by influenza A virus infection in human lung epithelial A549 cells. Silencing of cellular IKKγ by small interfering RNA led to enhanced replication of influenza viruses. Concomitantly, overexpression of IKKγ resulted in increased production of IFNα/β, whereas influenza virus infection completely eliminated the IKKγ-overexpression-induced production of IFNα/β. Our results suggest that IKKγ and influenza virus are mutually inhibitory, and influenza viruses may inhibit IFN production through suppressing the expression of IKKγ during viral infection.
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Affiliation(s)
- Yimeng Wang
- Department of Biological Sciences, SCEN 601, University of Arkansas, Fayetteville, Arkansas 72701, United States
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41
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Kreijtz JHCM, Fouchier RAM, Rimmelzwaan GF. Immune responses to influenza virus infection. Virus Res 2011; 162:19-30. [PMID: 21963677 DOI: 10.1016/j.virusres.2011.09.022] [Citation(s) in RCA: 227] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/15/2011] [Accepted: 09/15/2011] [Indexed: 10/17/2022]
Abstract
Influenza viruses cause annual outbreaks of respiratory tract infection with attack rates of 5-10%. This means that humans are infected repeatedly with intervals of, on average, 10-20 years. Upon each infection subjects develop innate and adaptive immune responses which aim at clearing the infection. Strain-specific antibody responses are induced, which exert selective pressure on circulating influenza viruses and which drive antigenic drift of seasonal influenza viruses, especially in the hemagglutinin molecule. This antigenic drift necessitates updating of seasonal influenza vaccines regularly in order to match the circulating strains. Upon infection also virus-specific T cell responses are induced, including CD4+ T helper cells and CD8+ cytotoxic T cells. These cells are mainly directed to conserved proteins and therefore display cross-reactivity with a variety of influenza A viruses of different subtypes. T cell mediated immunity therefore may contribute to so-called heterosubtypic immunity and may afford protection against antigenically distinct, potentially pandemic influenza viruses. At present, novel viral targets are identified that may help to develop broad-protective vaccines. Here we review the various arms of the immune response to influenza virus infections and their viral targets and discuss the possibility of developing universal vaccines. The development of such novel vaccines would imply that also new immune correlates of protection need to be established in order to facilitate assessment of vaccine efficacy.
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Affiliation(s)
- J H C M Kreijtz
- Department of Virology, Erasmus MC, Rotterdam, The Netherlands
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Knox C, Luke GA, Blatch GL, Pesce ER. Heat shock protein 40 (Hsp40) plays a key role in the virus life cycle. Virus Res 2011; 160:15-24. [DOI: 10.1016/j.virusres.2011.06.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Revised: 06/17/2011] [Accepted: 06/21/2011] [Indexed: 01/04/2023]
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Akarsu H, Iwatsuki-Horimoto K, Noda T, Kawakami E, Katsura H, Baudin F, Horimoto T, Kawaoka Y. Structure-based design of NS2 mutants for attenuated influenza A virus vaccines. Virus Res 2010; 155:240-8. [PMID: 20970464 DOI: 10.1016/j.virusres.2010.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2010] [Revised: 10/12/2010] [Accepted: 10/14/2010] [Indexed: 11/29/2022]
Abstract
We previously characterised the matrix 1 (M1)-binding domain of the influenza A virus NS2/nuclear export protein (NEP), reporting a critical role for the tryptophan (W78) residue that is surrounded by a cluster of glutamate residues in the C-terminal region that interacts with the M1 protein (Akarsu et al., 2003). To gain further insight into the functional role of this interaction, here we used reverse genetics to generate a series of A/WSN/33 (H1N1)-based NS2/NEP mutants for W78 or the C-terminal glutamate residues and assessed their effect on virus growth. We found that simultaneous mutations at three positions (E67S/E74S/E75S) of NS2/NEP were important for inhibition of influenza viral polymerase activity, although the W78S mutant and other glutamate mutants with single substitutions were not. In addition, double and triple substitutions in the NS2/NEP glutamine residues, which resulted in the addition of seven amino acids to the C-terminus of NS1 due to gene overlapping, resulted in virus attenuation in mice. Animal studies with this mutant suggest a potential benefit to incorporating these NS mutations into live vaccines.
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Affiliation(s)
- Hatice Akarsu
- Unit of Virus Host-Cell Interactions, UMI 3265, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France
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Versteeg GA, García-Sastre A. Viral tricks to grid-lock the type I interferon system. Curr Opin Microbiol 2010; 13:508-16. [PMID: 20538505 PMCID: PMC2920345 DOI: 10.1016/j.mib.2010.05.009] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 05/18/2010] [Indexed: 12/24/2022]
Abstract
Type I interferons (IFNs) play a crucial role in the innate immune avant-garde against viral infections. Virtually all viruses have developed means to counteract the induction, signaling, or antiviral actions of the IFN circuit. Over 170 different virus-encoded IFN antagonists from 93 distinct viruses have been described up to now, indicating that most viruses interfere with multiple stages of the IFN response. Although every viral IFN antagonist is unique in its own right, four main mechanisms are employed to circumvent innate immune responses: (i) general inhibition of cellular gene expression, (ii) sequestration of molecules in the IFN circuit, (iii) proteolytic cleavage, and (iv) proteasomal degradation of key components of the IFN system. The increasing understanding of how different viral IFN antagonists function has been translated to the generation of viruses with mutant IFN antagonists as potential live vaccine candidates. Moreover, IFN antagonists are attractive targets for inhibition by small-molecule compounds.
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Affiliation(s)
- Gijs A Versteeg
- Department of Microbiology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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Wolff T, Ludwig S. Influenza viruses control the vertebrate type I interferon system: factors, mechanisms, and consequences. J Interferon Cytokine Res 2010; 29:549-57. [PMID: 19708812 DOI: 10.1089/jir.2009.0066] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Virus research of the past decades showed that the vertebrate type I interferon (IFN) system is in principle capable of slowing down the replication and spread of most if not all viruses at early stages of infection. However, influenza viruses and other viral pathogens have evolved gene products to subvert this innate defense to enable efficient reproduction and thereby cause disease. Inhibition of type I IFN also impairs adaptive immune reactions as those cytokines function in the development of pathogen-specific cellular immunity. This article highlights the recent progress in our understanding of key interactions of influenza viruses with the type I IFN defense, which are central to viral virulence. A main focus is on corruptions of IFN-dependent antiviral functions mediated by the cellular receptors RIG-I and PKR and their blockade by the viral NS1 protein.
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Affiliation(s)
- Thorsten Wolff
- Robert Koch-Institute, Project Group P15, Berlin, Germany.
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Hrincius ER, Wixler V, Wolff T, Wagner R, Ludwig S, Ehrhardt C. CRK adaptor protein expression is required for efficient replication of avian influenza A viruses and controls JNK-mediated apoptotic responses. Cell Microbiol 2010; 12:831-43. [DOI: 10.1111/j.1462-5822.2010.01436.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Loss of function of the influenza A virus NS1 protein promotes apoptosis but this is not due to a failure to activate phosphatidylinositol 3-kinase (PI3K). Virology 2009; 396:94-105. [PMID: 19880155 DOI: 10.1016/j.virol.2009.10.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/17/2009] [Accepted: 10/05/2009] [Indexed: 11/23/2022]
Abstract
A panel of influenza A viruses encoding mutant NS1 proteins was created in which a number of NS1 functions, including interactions with dsRNA, PI3K, CPSF30 and PKR, were inhibited. Surprisingly, given previous reports that NS1 activates PI3K to prevent apoptosis, the mutant viruses rUd-Y89F and rUd-P164/7A that fail to activate PI3K did not induce any more apoptosis than wild-type virus in MRC-5 and A549 cells, even though these cells are highly sensitive to inducers of apoptosis. Induction of cell death by the apoptogenic rUd-184-8(P) virus could not be prevented by serum-mediated activation of PI3K/Akt. Neither infection of MRC-5 or A549 cells with wild-type virus nor constitutive expression of NS1 prevented cell death caused by apoptosis inducers, suggesting that NS1 is not directly anti-apoptotic. Our data suggest that the loss of a functionally intact NS1 protein promotes apoptosis, but this is not due to an inability to activate PI3K.
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Abstract
Influenza viruses continue to pose a major global public health problem. There is a need to better understand the pathogenicity and transmission of pandemic influenza viruses so that we may develop improved methods for their prevention and control. Reconstruction of the 1918 virus and studies elucidating the exceptional virulence and transmissibility of the virus are providing exciting new insights into this devastating pandemic strain. The primary approach has been to reconstruct and analyze recombinant viruses, in which genes of the 1918 virus are replaced with genes of contemporary influenza viruses of lesser virulence. This review highlights the current status of the field and discusses the molecular determinants of the 1918 pandemic virus that may have contributed to its virulence and spread. Identifying the exact genes responsible for the high virulence of the 1918 virus will be an important step toward understanding virulent influenza strains and will allow the world to better prepare for and respond to future influenza pandemics.
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Affiliation(s)
- Terrence M Tumpey
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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Dauber B, Wolff T. Activation of the Antiviral Kinase PKR and Viral Countermeasures. Viruses 2009; 1:523-44. [PMID: 21994559 PMCID: PMC3185532 DOI: 10.3390/v1030523] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 10/26/2009] [Accepted: 10/26/2009] [Indexed: 12/25/2022] Open
Abstract
The interferon-induced double-stranded (ds)RNA-dependent protein kinase (PKR) limits viral replication by an eIF2α-mediated block of translation. Although many negative-strand RNA viruses activate PKR, the responsible RNAs have long remained elusive, as dsRNA, the canonical activator of PKR, has not been detected in cells infected with such viruses. In this review we focus on the activating RNA molecules of different virus families, in particular the negative-strand RNA viruses. We discuss the recently identified non-canonical activators 5′-triphosphate RNA and the vRNP of influenza virus and give an update on strategies of selected RNA and DNA viruses to prevent activation of PKR.
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Affiliation(s)
- Bianca Dauber
- Department of Medical Microbiology & Immunology, University of Alberta, 632 Heritage Medical Research Center, Edmonton, AB, T6G 2S2, Canada
- Authors to whom correspondence should be addressed; E-Mails: (B.D.); (T.W.)
| | - Thorsten Wolff
- P15, Robert Koch-Institute/Nordufer 20, 13353 Berlin, Germany
- Authors to whom correspondence should be addressed; E-Mails: (B.D.); (T.W.)
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50
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Use of animal models to understand the pandemic potential of highly pathogenic avian influenza viruses. Adv Virus Res 2009; 73:55-97. [PMID: 19695381 DOI: 10.1016/s0065-3527(09)73002-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
It has been 40 years since the last influenza pandemic and it is generally considered that another could occur at any time. Recent introductions of influenza A viruses from avian sources into the human population have raised concerns that these viruses may be a source of a future pandemic strain. Therefore, there is a need to better understand the pathogenicity of avian influenza viruses for mammalian species so that we may be better able to predict the pandemic potential of such viruses and develop improved methods for their prevention and control. In this review, we describe the virulence of H5 and H7 avian influenza viruses in the mouse and ferret models. The use of these models is providing exciting new insights into the contribution of virus and host responses toward avian influenza viruses, virus tropism, and virus transmissibility. Identifying the role of individual viral gene products and mapping the molecular determinants that influence the severity of disease observed following avian influenza virus infection is dependent on the use of reliable animal models. As avian influenza viruses continue to cause human disease and death, animal pathogenesis studies identify avenues of investigation for novel preventative and therapeutic agents that could be effective in the event of a future pandemic.
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