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Wei Q, Wang W, Meng F, Wang Y, Wei N, Tian J, Li H, Hao Q, Zhou Z, Liu H, Yang Z, Xiao S. The W195 Residue of the Newcastle Disease Virus V Protein Is Critical for Multiple Aspects of Viral Self-Regulation through Interactions between V and Nucleoproteins. Viruses 2024; 16:584. [PMID: 38675926 PMCID: PMC11054343 DOI: 10.3390/v16040584] [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: 03/09/2024] [Revised: 04/03/2024] [Accepted: 04/07/2024] [Indexed: 04/28/2024] Open
Abstract
The transcription and replication of the Newcastle disease virus (NDV) strictly rely on the viral ribonucleoprotein (RNP) complex, which is composed of viral NP, P, L and RNA. However, it is not known whether other viral non-RNP proteins participate in this process for viral self-regulation. In this study, we used a minigenome (MG) system to identify the regulatory role of the viral non-RNP proteins V, M, W, F and HN. Among them, V significantly reduced MG-encoded reporter activity compared with the other proteins and inhibited the synthesis of viral mRNA and cRNA. Further, V interacted with NP. A mutation in residue W195 of V diminished V-NP interaction and inhibited inclusion body (IB) formation in NP-P-L-cotransfected cells. Furthermore, a reverse-genetics system for the highly virulent strain F48E9 was established. The mutant rF48E9-VW195R increased viral replication and apparently enhanced IB formation. In vivo experiments demonstrated that rF48E9-VW195R decreased virulence and retarded time of death. Overall, the results indicate that the V-NP interaction of the W195 mutant V decreased, which regulated viral RNA synthesis, IB formation, viral replication and pathogenicity. This study provides insight into the self-regulation of non-RNP proteins in paramyxoviruses.
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Affiliation(s)
- Qiaolin Wei
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Wenbin Wang
- Poultry Institute, Shandong Academy of Agricultural Science, Jinan 250100, China;
| | - Fanxing Meng
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Ying Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Ning Wei
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Jianxia Tian
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Hanlue Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Qiqi Hao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Zijie Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Haijin Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Zengqi Yang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
| | - Sa Xiao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Xianyang 712100, China; (Q.W.); (F.M.); (Y.W.); (N.W.); (J.T.); (H.L.); (Q.H.); (Z.Z.); (H.L.); (Z.Y.)
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Kitagawa Y, Tsukamoto T, Itoh M, Gotoh B. Middle East respiratory syndrome coronavirus
ORF4b
protein inhibits
TLR7
‐ and
TLR9
‐dependent alpha interferon induction. FEBS Lett 2022; 596:2538-2554. [DOI: 10.1002/1873-3468.14486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Yoshinori Kitagawa
- Division of Microbiology and Infectious Diseases, Department of Pathology Shiga University of Medical Science, Seta, Otsu Shiga 520‐2192 Japan
| | - Takumi Tsukamoto
- Department of Microbiology, Faculty of Bio‐Science Nagahama institute of Bio‐Science and Technology Nagahama Shiga 526‐0829 Japan
| | - Masae Itoh
- Department of Microbiology, Faculty of Bio‐Science Nagahama institute of Bio‐Science and Technology Nagahama Shiga 526‐0829 Japan
| | - Bin Gotoh
- Division of Microbiology and Infectious Diseases, Department of Pathology Shiga University of Medical Science, Seta, Otsu Shiga 520‐2192 Japan
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Wang C, Wang T, Duan L, Chen H, Hu R, Wang X, Jia Y, Chu Z, Liu H, Wang X, Zhang S, Xiao S, Wang J, Dang R, Yang Z. Evasion of Host Antiviral Innate Immunity by Paramyxovirus Accessory Proteins. Front Microbiol 2022; 12:790191. [PMID: 35173691 PMCID: PMC8841848 DOI: 10.3389/fmicb.2021.790191] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/22/2021] [Indexed: 01/01/2023] Open
Abstract
For efficient replication, viruses have developed multiple strategies to evade host antiviral innate immunity. Paramyxoviruses are a large family of enveloped RNA viruses that comprises diverse human and animal pathogens which jeopardize global public health and the economy. The accessory proteins expressed from the P gene by RNA editing or overlapping open reading frames (ORFs) are major viral immune evasion factors antagonizing type I interferon (IFN-I) production and other antiviral innate immune responses. However, the antagonistic mechanisms against antiviral innate immunity by accessory proteins differ among viruses. Here, we summarize the current understandings of immune evasion mechanisms by paramyxovirus accessory proteins, specifically how accessory proteins directly or indirectly target the adaptors in the antiviral innate immune signaling pathway to facilitate virus replication. Additionally, some cellular responses, which are also involved in viral replication, will be briefly summarized.
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Kitagawa Y, Yamaguchi M, Kohno M, Sakai M, Itoh M, Gotoh B. Respirovirus C protein inhibits activation of type I interferon receptor-associated kinases to block JAK-STAT signaling. FEBS Lett 2019; 594:864-877. [PMID: 31705658 DOI: 10.1002/1873-3468.13670] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/22/2019] [Accepted: 10/31/2019] [Indexed: 12/31/2022]
Abstract
Respirovirus C protein blocks the type I interferon (IFN)-stimulated activation of the JAK-STAT pathway. It has been reported that C protein inhibits IFN-α-stimulated tyrosine phosphorylation of STATs, but the underlying mechanism is poorly understood. Here, we show that the C protein of Sendai virus (SeV), a member of the Respirovirus genus, binds to the IFN receptor subunit IFN-α/β receptor subunit (IFNAR)2 and inhibits IFN-α-stimulated tyrosine phosphorylation of the upstream receptor-associated kinases, JAK1 and TYK2. Analysis of various SeV C mutant (Cm) proteins demonstrates the importance of the inhibitory effect on receptor-associated kinase phosphorylation for blockade of JAK-STAT signaling. Furthermore, this inhibitory effect and the IFNAR2 binding capacity are observed for all the respirovirus C proteins examined. Our results suggest that respirovirus C protein inhibits activation of the receptor-associated kinases JAK1 and TYK2 possibly through interaction with IFNAR2.
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Affiliation(s)
- Yoshinori Kitagawa
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Otsu, Japan
| | - Mayu Yamaguchi
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Otsu, Japan
| | - Miki Kohno
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Otsu, Japan.,Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Madoka Sakai
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Otsu, Japan.,Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Masae Itoh
- Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Bin Gotoh
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Otsu, Japan
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Sendai Virus V Protein Inhibits the Secretion of Interleukin-1β by Preventing NLRP3 Inflammasome Assembly. J Virol 2018; 92:JVI.00842-18. [PMID: 30021903 DOI: 10.1128/jvi.00842-18] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/03/2018] [Indexed: 12/20/2022] Open
Abstract
Inflammasomes play a key role in host innate immune responses to viral infection by caspase-1 (Casp-1) activation to facilitate interleukin-1β (IL-1β) secretion, which contributes to the host antiviral defense. The NLRP3 inflammasome consists of the cytoplasmic sensor molecule NLRP3, adaptor protein ASC, and effector protein pro-caspase-1 (pro-Casp-1). NLRP3 and ASC promote pro-Casp-1 cleavage, leading to IL-1β maturation and secretion. However, as a countermeasure, viral pathogens have evolved virulence factors to antagonize inflammasome pathways. Here we report that V gene knockout Sendai virus [SeV V(-)] induced markedly greater amounts of IL-1β than wild-type SeV in infected THP1 macrophages. Deficiency of NLRP3 in cells inhibited SeV V(-)-induced IL-1β secretion, indicating an essential role for NLRP3 in SeV V(-)-induced IL-1β activation. Moreover, SeV V protein inhibited the assembly of NLRP3 inflammasomes, including NLRP3-dependent ASC oligomerization, NLRP3-ASC association, NLRP3 self-oligomerization, and intermolecular interactions between NLRP3 molecules. Furthermore, a high correlation between the NLRP3-binding capacity of V protein and the ability to block inflammasome complex assembly was observed. Therefore, SeV V protein likely inhibits NLRP3 self-oligomerization by interacting with NLRP3 and inhibiting subsequent recruitment of ASC to block NLRP3-dependent ASC oligomerization, in turn blocking full activation of the NLRP3 inflammasome and thus blocking IL-1β secretion. Notably, the inhibitory action of SeV V protein on NLRP3 inflammasome activation is shared by other paramyxovirus V proteins, such as Nipah virus and human parainfluenza virus type 2. We thus reveal a mechanism by which paramyxovirus inhibits inflammatory responses by inhibiting NLRP3 inflammasome complex assembly and IL-1β activation.IMPORTANCE The present study demonstrates that the V protein of SeV, Nipah virus, and human parainfluenza virus type 2 interacts with NLRP3 to inhibit NLRP3 inflammasome activation, potentially suggesting a novel strategy by which viruses evade the host innate immune response. As all members of the Paramyxovirinae subfamily carry similar V genes, this new finding may also lead to identification of novel therapeutic targets for paramyxovirus infection and related diseases.
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Odkhuu E, Komatsu T, Koide N, Naiki Y, Takeuchi K, Tanaka Y, Tsolmongyn B, Jambalganiin U, Morita N, Yoshida T, Gotoh B, Yokochi T. Sendai virus C protein limits NO production in infected RAW264.7 macrophages. Innate Immun 2018; 24:430-438. [PMID: 30189760 PMCID: PMC6830875 DOI: 10.1177/1753425918796619] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
To suppress virus multiplication, infected macrophages produce NO. However, it
remains unclear how infecting viruses then overcome NO challenge. In the present
study, we report the effects of accessory protein C from Sendai virus (SeV), a
prototypical paramyxovirus, on NO output. We found that in RAW264.7 murine
macrophages, a mutant SeV without C protein (4C(–)) significantly enhanced
inducible NO synthase (iNOS) expression and subsequent NO production compared to
wild type SeV (wtSeV). SeV 4C(-) infection caused marked production of IFN-β,
which is involved in induction of iNOS expression via the JAK-STAT pathway.
Addition of anti-IFN-β Ab, however, resulted in only marginal suppression of NO
production. In contrast, NF-κB, a primarily important factor for transcription
of the iNOS gene, was also activated by 4C(–) infection but not
wtSeV infection. Induction of NO production and iNOS expression by 4C(–) was
significantly suppressed in cells constitutively expressing influenza virus NS1
protein that can sequester double-stranded (ds)RNA, which triggers activation of
signaling pathways leading to activation of NF-κB and IRF3. Therefore, C protein
appears to suppress NF-κB activation to inhibit iNOS expression and subsequent
NO production, possibly by limiting dsRNA generation in the context of viral
infection.
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Affiliation(s)
- Erdenezaya Odkhuu
- 1 Department of Anatomy, Mongolian National University of Medical Sciences, Mongolia
| | - Takayuki Komatsu
- 2 Department of Microbiology and Immunology, School of Medicine, Aichi Medical University, Japan
| | - Naoki Koide
- 2 Department of Microbiology and Immunology, School of Medicine, Aichi Medical University, Japan
| | - Yoshikazu Naiki
- 2 Department of Microbiology and Immunology, School of Medicine, Aichi Medical University, Japan
| | - Kenji Takeuchi
- 3 Department of Genome Science and Microbiology, Faculty of Medical Sciences, University of Fukui, Japan
| | - Yukie Tanaka
- 4 Department of Molecular Biology and Chemistry, Faculty of Medical Sciences, University of Fukui, Japan
| | - Bilegtsaikhan Tsolmongyn
- 2 Department of Microbiology and Immunology, School of Medicine, Aichi Medical University, Japan
| | | | - Naoko Morita
- 2 Department of Microbiology and Immunology, School of Medicine, Aichi Medical University, Japan
| | - Tomoaki Yoshida
- 2 Department of Microbiology and Immunology, School of Medicine, Aichi Medical University, Japan
| | - Bin Gotoh
- 5 Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Japan
| | - Takashi Yokochi
- 2 Department of Microbiology and Immunology, School of Medicine, Aichi Medical University, Japan
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Kitagawa Y, Sakai M, Shimojima M, Saijo M, Itoh M, Gotoh B. Nonstructural protein of severe fever with thrombocytopenia syndrome phlebovirus targets STAT2 and not STAT1 to inhibit type I interferon-stimulated JAK-STAT signaling. Microbes Infect 2018; 20:360-368. [PMID: 29886262 DOI: 10.1016/j.micinf.2018.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 01/17/2023]
Abstract
The nonstructural protein NSs of severe fever with thrombocytopenia syndrome phlebovirus blocks type I interferon (IFN)-stimulated JAK-STAT signaling. However, there is continuing controversy as to whether NSs targets STAT1 or STAT2 or both for this blockade. The present study was designed to gain a further understanding of the blockade mechanism. Immunoprecipitation experiments revealed a stronger interaction of NSs with STAT2 than with any other component constituting the JAK-STAT pathway. Expression of NSs resulted in the formation of cytoplasmic inclusion bodies (IBs), and affected cytoplasmic distribution of STAT2. STAT2 was relocated to NSs-induced IBs. Consequently, NSs inhibited IFN-α-stimulated tyrosine phosphorylation and nuclear translocation of STAT2. These inhibitory effects as well as the signaling blockade activity were not observed in NSs mutant proteins lacking the STAT2-binding ability. In contrast, NSs affected neither subcellular distribution nor phosphorylation of STAT1 in response to IFN-α and IFN-γ, demonstrating that NSs has little physical and functional interactions with STAT1. Taken together, these results suggest that NSs sequesters STAT2 into NSs-induced IBs, thereby blocking type I IFN JAK-STAT signaling.
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Affiliation(s)
- Yoshinori Kitagawa
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, 520-2192, Japan
| | - Madoka Sakai
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, 520-2192, Japan; Department of Microbiology, Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Masayuki Shimojima
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Masayuki Saijo
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Masae Itoh
- Department of Microbiology, Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Bin Gotoh
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, 520-2192, Japan.
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Possible role of the Nipah virus V protein in the regulation of the interferon beta induction by interacting with UBX domain-containing protein1. Sci Rep 2018; 8:7682. [PMID: 29769705 PMCID: PMC5955904 DOI: 10.1038/s41598-018-25815-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 04/17/2018] [Indexed: 02/08/2023] Open
Abstract
Nipah virus (NiV) is a highly pathogenic paramyxovirus that causes lethal encephalitis in humans. We previously reported that the V protein, one of the three accessory proteins encoded by the P gene, is one of the key determinants of the pathogenesis of NiV in a hamster infection model. Satterfield B.A. et al. have also revealed that V protein is required for the pathogenicity of henipavirus in a ferret infection model. However, the complete functions of NiV V have not been clarified. In this study, we identified UBX domain-containing protein 1 (UBXN1), a negative regulator of RIG-I-like receptor signaling, as a host protein that interacts with NiV V. NiV V interacted with the UBX domain of UBXN1 via its proximal zinc-finger motif in the C-terminal domain. NiV V increased the level of UBXN1 protein by suppressing its proteolysis. Furthermore, NiV V suppressed RIG-I and MDA5-dependent interferon signaling by stabilizing UBXN1 and increasing the interaction between MAVS and UBXN1 in addition to directly interrupting the activation of MDA5. Our results suggest a novel molecular mechanism by which the induction of interferon is potentially suppressed by NiV V protein via UBXN1.
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Inflammasome Antagonism by Human Parainfluenza Virus Type 3 C Protein. J Virol 2018; 92:JVI.01776-17. [PMID: 29187536 DOI: 10.1128/jvi.01776-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/02/2017] [Indexed: 01/21/2023] Open
Abstract
Human parainfluenza virus type 3 (HPIV3) is a negative-sense single-stranded RNA virus belonging to the Paramyxoviridae family. HPIV3 is a lung-tropic virus causing airway diseases, including pneumonia, croup, and bronchiolitis, during infancy and childhood. The activation of the inflammasome by pathogens results in the production of proinflammatory cytokines such as interleukin-1β (IL-1β) during infection. Thus, the inflammasome-mediated proinflammatory response plays a critical role in regulating the immune response and virus clearance. The inflammasome is a multimeric protein complex triggering caspase-1 activation. Activated caspase-1 cleaves pro-IL-1β into its mature (and active) secretory form. Our study revealed inflammasome activation in macrophages following HPIV3 infection. Specifically, the activation of the NLRP3/ASC inflammasome resulted in the production of mature IL-1β from HPIV3-infected cells. Furthermore, Toll-like receptor 2 (TLR2) activation (first signal) and potassium efflux (second signal) constituted two cellular events mediating inflammasome activation following HPIV3 infection. During our studies, we surprisingly identified the HPIV3 C protein as an antagonist of inflammasome activation. The HPIV3 C protein is an accessory protein encoded by the open reading frame of the viral phosphoprotein (P) gene. The HPIV3 C protein interacted with the NLRP3 protein and blocked inflammasome activation by promoting the proteasomal degradation of the NLRP3 protein. Thus, our studies report NLRP3/ASC inflammasome activation by HPIV3 via TLR2 signaling and potassium efflux. Furthermore, we have identified HPIV3 C as a viral component involved in antagonizing inflammasome activation.IMPORTANCE Human parainfluenza virus type 3 (HPIV3) is a paramyxovirus that causes respiratory tract diseases during infancy and childhood. Currently, there is no effective vaccine or antiviral therapy for HPIV3. Therefore, in order to develop anti-HPIV3 agents (therapeutics and vaccines), it is important to study the HPIV3-host interaction during the immune response. Inflammasomes play an important role in the immune response. Inflammasome activation by HPIV3 has not been previously reported. Our studies demonstrated inflammasome activation by HPIV3 in macrophages. Specifically, HPIV3 activated the NLRP3/ASC inflammasome by TLR2 activation and potassium efflux. C proteins of paramyxoviruses are accessory proteins encoded by the viral phosphoprotein gene. The role of the C protein in inflammasome regulation was unknown. Surprisingly, our studies revealed that the HPIV3 C protein antagonizes inflammasome activation. In addition, we highlighted for the first time a mechanism utilized by paramyxovirus accessory proteins to block inflammasome activation. The HPIV3 C protein interacted with the NLRP3 protein to trigger the proteasomal degradation of the NLRP3 protein.
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Marsili G, Perrotti E, Remoli AL, Acchioni C, Sgarbanti M, Battistini A. IFN Regulatory Factors and Antiviral Innate Immunity: How Viruses Can Get Better. J Interferon Cytokine Res 2018; 36:414-32. [PMID: 27379864 DOI: 10.1089/jir.2016.0002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The interferon regulatory factor (IRF) family consists of transcriptional regulators that exert multifaceted and versatile functions in multiple biological processes. Their crucial role as central mediators in the establishment and execution of host immunity in response to pathogen-derived signals downstream pattern recognition receptors (PRRs) makes IRFs a hallmark of the host antiviral response. They function as hub molecules at the crossroad of different signaling pathways for the induction of interferon (IFN) and inflammatory cytokines, as well as of antiviral and immunomodulatory genes even in an IFN-independent manner. By regulating the development and activity of immune cells, IRFs also function as a bridge between innate and adaptive responses. As such, IRFs represent attractive and compulsive targets in viral strategies to subvert antiviral signaling. In this study, we discuss current knowledge on the wide array of strategies put in place by pathogenic viruses to evade, subvert, and/or hijack these essential components of host antiviral immunity.
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Affiliation(s)
- Giulia Marsili
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Edvige Perrotti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Anna Lisa Remoli
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Chiara Acchioni
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Marco Sgarbanti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Angela Battistini
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
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Human Metapneumovirus M2-2 Protein Acts as a Negative Regulator of Alpha Interferon Production by Plasmacytoid Dendritic Cells. J Virol 2017; 91:JVI.00579-17. [PMID: 28768858 DOI: 10.1128/jvi.00579-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/24/2017] [Indexed: 12/20/2022] Open
Abstract
Human metapneumovirus (HMPV) has the ability to inhibit Toll-like receptor 7 (TLR7)- and TLR9-dependent alpha interferon (IFN-α) production by plasmacytoid dendritic cells (pDCs). However, the inhibition mechanism remains largely unknown. To identify viral proteins responsible for this inhibition, we performed a screening of HMPV open reading frames (ORFs) for the ability to block TLR7/9-dependent signaling reconstituted in HEK293T cells by transfection with myeloid differentiation factor 88 (MyD88), tumor necrosis factor receptor-associated factor 6 (TRAF6), IKKα, and IFN regulatory factor 7 (IRF7). This screening demonstrated that the M2-2 protein was the most potent inhibitor of TLR7/9-dependent IFN-α induction. A recombinant HMPV in which the M2-2 ORF was silenced indeed induced greater IFN-α production by human pDCs than wild-type HMPV did. Immunoprecipitation experiments showed direct physical association of the M2-2 protein with the inhibitory domain (ID) of IRF7. As a natural consequence of this, transfection of IRF7 lacking the ID, a constitutively active mutant, resulted in activation of the IFN-α promoter even in the presence of M2-2. Bioluminescence resonance energy transfer assays and split Renilla luciferase complementation assays revealed that M2-2 inhibited MyD88/TRAF6/IKKα-induced homodimerization of IRF7. In contrast, expression of the M2-2 protein did not result in inhibition of IPS-1-induced homodimerization and resultant activation of IRF7. This indicates that inhibition of MyD88/TRAF6/IKKα-induced IRF7 homodimerization does not result from a steric effect of M2-2 binding. Instead, it was found that M2-2 inhibited MyD88/TRAF6/IKKα-induced phosphorylation of IRF7 on Ser477. These results suggest that M2-2 blocks TLR7/9-dependent IFN-α induction by preventing IRF7 homodimerization, possibly through its effects on the phosphorylation status of IRF7.IMPORTANCE The family Paramyxoviridae is divided into two subfamilies, the Paramyxovirinae and the Pneumovirinae Members of the subfamily Paramyxovirinae have the ability to inhibit TLR7/9-dependent IFN-α production, and the underlying inhibition mechanism has been intensively studied. In contrast, little is known about how members of the subfamily Pneumovirinae regulate IFN-α production by pDCs. We identified the M2-2 protein of HMPV, a member of the subfamily Pneumovirinae, as a negative regulator of IFN-α production by pDCs and uncovered the underlying mechanism. This study explains in part why the M2-2 knockout recombinant HMPV is attenuated and further suggests that M2-2 is a potential target for HMPV therapy.
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Ohta K, Matsumoto Y, Yumine N, Nishio M. Human parainfluenza virus type 2 V protein inhibits induction of tetherin. Med Microbiol Immunol 2017; 206:311-318. [PMID: 28455649 DOI: 10.1007/s00430-017-0508-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/22/2017] [Indexed: 10/19/2022]
Abstract
Tetherin is an anti-viral factor that restricts viral budding through tethering virions to the cell surface. The human parainfluenza virus type 2 (hPIV-2) V protein decreases cell surface tetherin in HeLa cells, which constitutively express endogenous tetherin. However, the role of the hPIV-2 V protein in tetherin induction remains unclear. Here, we examined whether hPIV-2 infection itself induces tetherin in HEK293 cells that have no basal expression of tetherin. Unlike influenza A virus (IAV) infection, hPIV-2 infection induced neither tetherin mRNA nor protein expression. In contrast, robust tetherin induction was observed by infection of rPIV-2s carrying V mutants, in which either three Trp residues (W178H/W182E/W192A) or Cys residues (C209/211/214A) that are important for decreasing cell surface tetherin are mutated. hPIV-2 infection also inhibited the induction of tetherin expression by IFN-α and IAV infection. Furthermore, hPIV-2 V protein but not P and VW178H/W182E/W192A suppressed tetherin induction. Our data collectively suggest that the hPIV-2 V protein inhibits tetherin expression induced by several external stimuli.
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Affiliation(s)
- Keisuke Ohta
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1, Kimiidera, Wakayama, 641-8509, Japan
| | - Yusuke Matsumoto
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1, Kimiidera, Wakayama, 641-8509, Japan
| | - Natsuko Yumine
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1, Kimiidera, Wakayama, 641-8509, Japan
| | - Machiko Nishio
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1, Kimiidera, Wakayama, 641-8509, Japan.
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14
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Głobińska A, Pawełczyk M, Piechota-Polańczyk A, Olszewska-Ziąber A, Moskwa S, Mikołajczyk A, Jabłońska A, Zakrzewski PK, Brauncajs M, Jarzębska M, Taka S, Papadopoulos NG, Kowalski ML. Impaired virus replication and decreased innate immune responses to viral infections in nasal epithelial cells from patients with allergic rhinitis. Clin Exp Immunol 2016; 187:100-112. [PMID: 27667736 DOI: 10.1111/cei.12869] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2016] [Indexed: 12/17/2022] Open
Abstract
The aim of this study was to assess the immune response to parainfluenza virus type 3 (PIV3), rhinovirus 1B (RV1B) and intracellular Toll-like receptors (TLR) agonists in nasal epithelial cells (NECs) from patients with allergic rhinitis and healthy controls. NECs were obtained from eight patients with allergic rhinitis (AR) and 11 non-atopic healthy controls (HC) by nasal scraping, grown to confluence and exposed to PIV3, RV1B infection or TLR-3 and TLR-7/8 agonists. Interferon (IFN)-λ1, IFN-α, IFN-β and regulated on activation, normal T expressed and secreted (RANTES) release into the cell culture supernatants was assessed at 8, 24 and 48 h upon infection or 8 and 24 h after stimulation with poly(I:C) and R848. mRNA levels of IFNs, RANTES, interferon regulatory transcription factor (IRF)3, IRF7 and viral gene copy number were determined using real-time polymerase chain reaction (RT-PCR). PIV3 but not RV1B replication 48 h after infection was significantly lower (P < 0·01) in NECs from AR patients compared to HC. PIV3 infection induced significantly less IFN-λ1 (both protein and mRNA) in NECs from AR compared to HC. IFN-β mRNA expression and RANTES protein release and mRNA expression tended to be smaller in AR compared HC cells in response to both viruses. Stimulation with TLR-3 agonist [poly (I:C)] induced similar IFN-λ1 and RANTES generation in AR and HC subjects. Viral infections in NECs induced IRF7 expression, which correlated with IFN and RANTES expression. These data suggest that virus proliferation rates and the immune response profile are different in nasal epithelial cells from patients with allergic rhinitis compared to healthy individuals.
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Affiliation(s)
- A Głobińska
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
| | - M Pawełczyk
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
| | - A Piechota-Polańczyk
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
| | - A Olszewska-Ziąber
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
| | - S Moskwa
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland.,Microbiology and Laboratory Medical Immunology Department, Medical University of Łódź, Łódź, Poland
| | - A Mikołajczyk
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
| | - A Jabłońska
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
| | - P K Zakrzewski
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
| | - M Brauncajs
- Microbiology and Laboratory Medical Immunology Department, Medical University of Łódź, Łódź, Poland
| | - M Jarzębska
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
| | - S Taka
- Allergy Department, Second Paediatric Clinic, University of Athens, Athens, Greece
| | - N G Papadopoulos
- Allergy Department, Second Paediatric Clinic, University of Athens, Athens, Greece
| | - M L Kowalski
- Department of Immunology, Rheumatology and Allergy, Medical University of Łódź, Łódź, Poland.,Healthy Ageing Research Center, Medical University of Łódź, Łódź, Poland
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15
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Matsumoto Y, Ohta K, Yumine N, Goto H, Nishio M. Identification of two essential aspartates for polymerase activity in parainfluenza virus L protein by a minireplicon system expressing secretory luciferase. Microbiol Immunol 2016; 59:676-83. [PMID: 26446904 DOI: 10.1111/1348-0421.12329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/11/2015] [Accepted: 10/03/2015] [Indexed: 01/10/2023]
Abstract
Gene expression of nonsegmented negative-strand RNA viruses (nsNSVs) such as parainfluenza viruses requires the RNA synthesis activity of their polymerase L protein; however, the detailed mechanism of this process is poorly understood. In this study, a parainfluenza minireplicon assay expressing secretory Gaussia luciferase (Gluc) was established to analyze large protein (L) activity. Measurement of Gluc expression in the culture medium of cells transfected with the minigenome and viral polymerase components enabled quick and concise calculation of L activity. By comparing the amino acid sequences in conserved region III (CRIII), a putative polymerase-active domain of the L protein, two strictly conserved aspartates were identified in all families of nsNSV. A series of L mutants from human parainfluenza virus type 2 and parainfluenza virus type 5 showed that these aspartates are necessary for reporter gene expression. It was also confirmed that these aspartates are important for the production of viral mRNA and antigenome cRNA, but not for a polymerase-complex formation. These findings suggest that these two aspartates are key players in the nucleotidyl transfer reaction using two metal ions.
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Affiliation(s)
- Yusuke Matsumoto
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Keisuke Ohta
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Natsuko Yumine
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Hideo Goto
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Machiko Nishio
- Department of Microbiology, School of Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
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16
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Jaijyan DK, Singh H, Singh AP. A Sporozoite- and Liver Stage-expressed Tryptophan-rich Protein Plays an Auxiliary Role in Plasmodium Liver Stage Development and Is a Potential Vaccine Candidate. J Biol Chem 2015; 290:19496-511. [PMID: 25960542 DOI: 10.1074/jbc.m114.588129] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Indexed: 01/07/2023] Open
Abstract
The liver stages of the malaria parasite are clinically silent and constitute ideal targets for causal prophylactic drugs and vaccines. Cellular and molecular events responsible for liver stage development are poorly characterized. Here, we show that sporozoite, liver stage tryptophan-rich protein (SLTRiP) forms large multimers. Mice immunized with a purified recombinant SLTRiP protein gave high antibody titers in both inbred and outbred mice. Immunized mice showed highly significant levels of protection upon challenge with sporozoites and exhibited 10,000-fold fewer parasite 18S-rRNA copy numbers in their livers. The protection offered by immunization with SLTRiP came mainly from T-cells, and antibodies had little role to play despite their high titers. Immunofluorescence assays showed that SLTRiP is expressed in the sporozoite and early to late liver stages of malaria parasites. SLTRiP protein is exported to the cytosol of infected host cells during the early hours of parasite infection. Parasites deficient in SLTRiP were moderately defective in liver stage parasite development. A transcriptome profile of SLTRiP-deficient parasite-infected hepatocytes highlighted that SLTRiP interferes with multiple pathways in the host cell. We have demonstrated a role for SLTRiP in sporozoites and the liver stage of malaria parasites.
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Affiliation(s)
- Dabbu Kumar Jaijyan
- From the Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Himanshu Singh
- From the Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Agam Prasad Singh
- From the Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
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17
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Yamaguchi M, Kitagawa Y, Zhou M, Itoh M, Gotoh B. An anti-interferon activity shared by paramyxovirus C proteins: inhibition of Toll-like receptor 7/9-dependent alpha interferon induction. FEBS Lett 2013; 588:28-34. [PMID: 24269682 DOI: 10.1016/j.febslet.2013.11.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 10/31/2013] [Accepted: 11/06/2013] [Indexed: 10/26/2022]
Abstract
Paramyxovirus C protein targets the host interferon (IFN) system for virus immune evasion. To identify its unknown anti-IFN activity, we examined the effect of Sendai virus C protein on activation of the IFN-α promoter via various signaling pathways. This study uncovers a novel ability of C protein to block Toll-like receptor (TLR) 7- and TLR9-dependent IFN-α induction, which is specific to plasmacytoid dendritic cells. C protein interacts with a serine/threonine kinase IKKα and inhibits phosphorylation of IRF7. This anti-IFN activity of C protein is shared across genera of the Paramyxovirinae, and thus appears to play an important role in paramyxovirus immune evasion.
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Affiliation(s)
- Mayu Yamaguchi
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
| | - Yoshinori Kitagawa
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
| | - Min Zhou
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
| | - Masae Itoh
- Department of Microbiology, Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga 526-0829, Japan
| | - Bin Gotoh
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2192, Japan.
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18
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Perrotti E, Marsili G, Sgarbanti M, Remoli AL, Fragale A, Acchioni C, Orsatti R, Battistini A. IRF-7: an antiviral factor and beyond. Future Virol 2013. [DOI: 10.2217/fvl.13.88] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
This review will summarize main characteristics and functions of IRF-7. IRF-7 and the highly homologous IRF-3 are two members of the IRF family of transcription factors that have emerged as crucial regulators of type I interferon (IFN) in response to pathogenic infections downstream pathogen recognition receptors. IRF-7 is also part of a positive-feedback regulatory loop essential for sustained IFN responses. Thus, tight regulation of its expression and activity is necessary to balance IFN-mediated beneficial effects and unwanted pathological consequences of IFN overproduction. Its role as an antiviral factor independent of IFN expression, and its involvement in other cellular functions beyond antiviral functions, including regulation of oncogenesis and metabolism, underscore its important role in the regulation of cellular homeostasis.
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Affiliation(s)
- Edvige Perrotti
- Department of Infectious, Parasitic & Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Giulia Marsili
- Department of Infectious, Parasitic & Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Marco Sgarbanti
- Department of Infectious, Parasitic & Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Anna Lisa Remoli
- Department of Infectious, Parasitic & Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Alessandra Fragale
- Department of Infectious, Parasitic & Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Chiara Acchioni
- Department of Infectious, Parasitic & Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Roberto Orsatti
- Department of Infectious, Parasitic & Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Angela Battistini
- Department of Infectious, Parasitic & Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
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19
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Drake MG, Kaufman EH, Fryer AD, Jacoby DB. The therapeutic potential of Toll-like receptor 7 stimulation in asthma. ACTA ACUST UNITED AC 2013; 11:484-91. [PMID: 23078048 DOI: 10.2174/187152812803589967] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 05/20/2012] [Accepted: 05/21/2012] [Indexed: 01/21/2023]
Abstract
Asthma is an inflammatory disorder of the airways frequently characterized by an excessive Th2 adaptive immune response. Activation of Toll-like receptor (TLR)-7, a single-stranded viral RNA receptor that is highly expressed in the airways, triggers a rapid innate immune response and favors a subsequent Th1 response. Because of this role in pulmonary immunoregulation, TLR7 has gained considerable interest as a therapeutic target in asthma. Synthetic TLR7 ligands, including the imidazoquinolines imiquimod (R837) and resiquimod (R848), and 8-hydroxyadenine derivatives have been developed for other clinical indications. TLR7 activation prevents ovalbumin-induced airway hyperreactivity, eosinophilic inflammation, goblet cell hyperplasia and airway remodeling in murine models of asthma. TLR7 activation also inhibits viral replication in the lung and prevents virus-induced airway hyperreactivity. Furthermore, it has recently been shown that stimulating TLR7 rapidly relaxes airway smooth muscle, dilating the airways. This bronchodilating effect, which occurs in seconds to minutes and depends on rapid production of nitric oxide, indicates that TLR7 can signal via previously unrecognized pathways. The effects of decreasing the allergic Th2 response, acting as an immediate bronchodilator, and promoting an antiviral immune environment, make TLR7 an attractive drug target. We examine the current understanding of TLR7 as a therapeutic target and its translation to asthma treatment in humans.
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Affiliation(s)
- Matthew G Drake
- Division of Pulmonary and Critical Care Medicine, Oregon Health and Science University, Portland, Oregon, USA
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20
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Human parainfluenza virus type 2 V protein inhibits TRAF6-mediated ubiquitination of IRF7 to prevent TLR7- and TLR9-dependent interferon induction. J Virol 2013; 87:7966-76. [PMID: 23678181 DOI: 10.1128/jvi.03525-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Paramyxovirus V proteins block Toll-like receptor 7 (TLR7)- and TLR9-dependent signaling leading to alpha interferon production. Our recent study has provided evidence that interaction of the V proteins with IRF7 is important for the blockade. However, the detailed mechanisms still remain unclear. Here we reexamined the interaction of the human parainfluenza virus type 2 (HPIV2) V protein with signaling molecules involved in TLR7/9-dependent signaling. Immunoprecipitation experiments in HEK293T cells transfected with V protein and one of the signaling molecules revealed that the V protein interacted with not only IRF7 but also TRAF6, IKKα, and MyD88. Whereas overexpression of TRAF6 markedly enhanced the level of V protein associating with IRF7, IKKα, and MyD88 in HEK293T cells, the level of V protein associating with TRAF6 was little affected by overexpression of IRF7, IKKα, and MyD88. Moreover, knockdown or knockout of endogenous TRAF6 in HEK293T or mouse embryonic fibroblast cells resulted in dissociation of the V protein from IRF7, IKKα, and MyD88. These results demonstrate that binding of the V protein to IRF7, IKKα, and MyD88 is largely indirect and mediated by endogenous TRAF6. It was found that the V protein inhibited TRAF6-mediated lysine 63 (K63)-linked polyubiquitination of IRF7, which is prerequisite for IRF7 activation. Disruption of the tryptophan-rich motif of the V protein significantly affected its TRAF6-binding efficiency, which correlated well with the magnitude of inhibition of K63-linked polyubiquitination and the resultant activation of IRF7. Taken together, these results suggest that the HPIV2 V protein prevents TLR7/9-dependent interferon induction by inhibiting TRAF6-mediated K63-linked polyubiquitination of IRF7.
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21
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Taylor KE, Mossman KL. Recent advances in understanding viral evasion of type I interferon. Immunology 2013; 138:190-7. [PMID: 23173987 PMCID: PMC3573272 DOI: 10.1111/imm.12038] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 10/11/2012] [Accepted: 11/14/2012] [Indexed: 12/21/2022] Open
Abstract
The type I interferon (IFN) system mediates a wide variety of antiviral effects and represents an important first barrier to virus infection. Consequently, viruses have developed an impressive diversity of tactics to circumvent IFN responses. Evasion strategies can involve preventing initial virus detection, via the disruption of the Toll‐like receptors or the retinoic acid inducible gene I (RIG‐I) ‐like receptors, or by avoiding the initial production of the ligands recognized by these receptors. An alternative approach is to preclude IFN production by disarming or degrading the transcription factors involved in the expression of IFN, such as interferon regulatory factor 3 (IRF3)/IRF7, nuclear factor‐κB (NF‐κB), or ATF‐2/c‐jun, or by inducing a general block on host cell transcription. Viruses also oppose IFN signalling, both by disturbing the type I IFN receptor and by impeding JAK/STAT signal transduction upon IFN receptor engagement. In addition, the global expression of IFN‐stimulated genes (ISGs) can be obstructed via interference with epigenetic signalling, and specific ISGs can also be selectively targeted for inhibition. Finally, some viruses disrupt IFN responses by co‐opting negative regulatory systems, whereas others use antiviral mechanisms to their own advantage. Here, we review recent developments in this field.
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Affiliation(s)
- Kathryne E Taylor
- Department of Biochemistry and Biomedical Sciences, McMaster Immunology Research Centre, Michael DeGroote Centre for Learning and Discovery, McMaster University, Hamilton, ON, Canada
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22
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Tyagi RK, Sharma YD. Erythrocyte Binding Activity Displayed by a Selective Group of Plasmodium vivax Tryptophan Rich Antigens Is Inhibited by Patients' Antibodies. PLoS One 2012; 7:e50754. [PMID: 23236392 PMCID: PMC3516511 DOI: 10.1371/journal.pone.0050754] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 10/24/2012] [Indexed: 01/03/2023] Open
Abstract
Plasmodium vivax is a very common but non-cultivable malaria parasite affecting large human population in tropical world. To develop therapeutic reagents for this malaria, the parasite molecules involved in host-parasite interaction need to be investigated as they form effective vaccine or drug targets. We have investigated here the erythrocyte binding activity of a group of 15 different Plasmodium vivax tryptophan rich antigens (PvTRAgs). Only six of them, named PvTRAg, PvTRAg38, PvTRAg33.5, PvTRAg35.2 PvTRAg69.4 and PvATRAg74, showed binding to host erythrocytes. That the PvTRAgs binding to host erythrocytes was specific was evident from the competitive inhibition and saturation kinetics results. The erythrocyte receptors for these six PvTRAgs were resistant to trypsin and neuraminidase. These receptors were also chymotrypsin resistant except the receptors for PvTRAg38 and PvATRAg74 which were partially sensitive to this enzyme. The cross-competition studies showed that the chymotrypsin resistant RBC receptor for each of these two proteins was different. Altogether, there seems to be three RBC receptors for these six PvTRAgs and each PvTRAg has two RBC receptors. Both RBC receptors for PvTRAg, PvTRAg69.4, PvTRAg33.5, and PvTRAg35.2 were common to all these four proteins. These four PvTRAgs also shared one of their RBC receptors with PvTRAg38 as well as with PvATRAg74. The erythrocyte binding activity of these six PvTRAgs was inhibited by the respective rabbit polyclonal antibodies as well as by the natural antibodies produced by the P. vivax exposed individuals. It is concluded that only selective few PvTRAgs show erythrocyte binding activity involving different receptor molecules which can be blocked by the natural antibodies. Further studies on these receptor and ligands may lead to the development of therapeutic reagents for P. vivax malaria.
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Affiliation(s)
- Rupesh Kumar Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Yagya Dutta Sharma
- Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
- * E-mail:
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23
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F-actin modulates measles virus cell-cell fusion and assembly by altering the interaction between the matrix protein and the cytoplasmic tail of hemagglutinin. J Virol 2012; 87:1974-84. [PMID: 23221571 DOI: 10.1128/jvi.02371-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Actin filament (F-actin) is believed to be involved in measles virus (MV) assembly as a cellular factor, but the precise roles remain unknown. Here we show that Phe at position 50 of the MV matrix (M) protein is important for its association with F-actin, through which the function of the M protein is regulated. In plasmid-expressed or MV-infected cells, a coimmunoprecipitation study revealed that the wild-type M (M-WT) protein associated strongly with F-actin but only weakly with the cytoplasmic tail of the hemagglutinin (H) protein. Since the F50P mutation allowed the M protein the enhanced interaction with the H protein in return for the sharply declined association with F-actin, the mutant M (M-F50P) protein strongly inhibited MV cell-cell fusion and promoted the uptake of the H protein into virus particles. The abundantly incorporated H protein resulted in the increase in infectivity of the F50P virus, although the virus contained a level of genome RNA equal to that of the WT virus. When the structure of F-actin was disrupted with cytochalasin D, the M-WT protein liberated from F-actin interacted with the H protein as tightly as the M-F50P protein, suppressing cell-cell fusion and promoting virus assembly comparably efficiently as the M-F50P protein. The cell-cell fusion activity of the WT virus appeared to be upheld by F-actin, which prevents the M protein interaction with the H protein. Our results indicate that F-actin in association with the M protein alters the interaction between the M and H proteins, thereby modulating MV cell-cell fusion and assembly.
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24
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Zhou M, Kitagawa Y, Yamaguchi M, Uchiyama C, Itoh M, Gotoh B. Expeditious neutralization assay for human metapneumovirus based on a recombinant virus expressing Renilla luciferase. J Clin Virol 2012; 56:31-6. [PMID: 23084005 DOI: 10.1016/j.jcv.2012.09.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 09/25/2012] [Accepted: 09/28/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND Human metapneumovirus (HMPV) is a common cause of respiratory diseases in persons of all ages. Because of its slow replication and weak cytopathic effect in cultured cells, conventional neutralization assays for HMPV require around one week for completion. OBJECTIVES The purpose of this study is to establish a rapid neutralization assay based on a recombinant virus expressing Renilla luciferase (Rluc). STUDY DESIGN A recombinant HMPV expressing both Rluc and green fluorescent protein (GFP) was created by reverse genetics method. Two-fold serial dilutions of human 23 sera were made in a 96-well plate and incubated with 50 pfu/well of the recombinant virus at 4°C for 1 h. The mixtures were then transferred to LLC-MK2 cells in a 96-well plate, incubated for 2 h, and replaced with trypsin-free fresh media. After incubation at 32°C for 24 h, the cells were lysed and measured for Rluc activity. The neutralization titer was defined as the reciprocal of the highest serum dilution that resulted in 50% reduction of Rluc activity. RESULTS The novel assay could be completed within 24 h and eliminated the requirement of trypsin supporting multistep replication in cultured cells, as well as laborious processes including the plaque assay with immunostaining. Neutralization titers correlated well with those determined by a GFP-based assay previously developed. CONCLUSIONS The neutralization assay based on Rluc activity is the fastest and the most straightforward of all previous assays, and may be available for high throughput screening of neutralizing antibodies.
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Affiliation(s)
- Min Zhou
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
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Mechanism of inhibition of lipopolysaccharide-induced interferon-β production by 2-aminopurine. Mol Immunol 2012; 52:299-304. [PMID: 22750230 DOI: 10.1016/j.molimm.2012.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/06/2012] [Indexed: 11/21/2022]
Abstract
2-Aminopurine (2-AP) is widely used as an inhibitor for double stranded RNA-dependent protein kinase (PKR). Previously, we reported that 2-AP inhibits Toll-like receptor (TLR) ligand-induced nitric oxide production through the prevention of interferon (IFN)-β production. In this study, we investigated the mechanisms for 2-AP inhibition of lipopolysaccharide (LPS)-induced IFN-β production. A reporter gene assay showed that LPS-induced IFN-β promoter, but not nuclear factor (NF)-κB, activation was significantly inhibited by 2-AP. IFN-β promoter activation induced by the overexpression of Toll/interleukin-1 receptor domain-containing adaptor inducing IFN-β (TRIF) was significantly inhibited by 2-AP in a dose-dependent manner, while TRIF- or myeloid differentiation primary response gene 88-dependent NF-κB activation was not inhibited. IFN-β promoter activation induced by expression of the downstream signaling molecules, tumor necrosis factor receptor-associated factor family member-associated NF-κB activator-binding kinase 1, inhibitor of NF-κB kinase i and a constitutively active mutant of interferon regulatory factor (IRF)-3, was also inhibited by 2-AP. Another PKR inhibitor harboring the imidazolo-oxindole structure, however, did not affect TRIF signaling molecules-induced IFN-β promoter activation, suggesting that the inhibition of IFN-β transcription by 2-AP is independent of PKR inhibition. Further, we examined the effect of 2-AP on LPS-induced IRF-3 activation by immunoblotting. While 2-AP did not affect LPS-induced phosphorylation of IRF-3, nuclear translocation of IRF-3 was inhibited. Moreover, we revealed that LPS-induced phosphorylation of Akt, another key molecule involved in IRF-3 activation, was inhibited by 2-AP. These results suggest that 2-AP inhibits nuclear translocation of phosphorylated-IRF-3 by inhibiting Akt activation.
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Inhibition of interferon regulatory factor 3 activation by paramyxovirus V protein. J Virol 2012; 86:7136-45. [PMID: 22532687 DOI: 10.1128/jvi.06705-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The V protein of Sendai virus (SeV) suppresses innate immunity, resulting in enhancement of viral growth in mouse lungs and viral pathogenicity. The innate immunity restricted by the V protein is induced through activation of interferon regulatory factor 3 (IRF3). The V protein has been shown to interact with melanoma differentiation-associated gene 5 (MDA5) and to inhibit beta interferon production. In the present study, we infected MDA5-knockout mice with V-deficient SeV and found that MDA5 was largely unrelated to the innate immunity that the V protein suppresses in vivo. We therefore investigated the target of the SeV V protein. We previously reported interaction of the V protein with IRF3. Here we extended the observation and showed that the V protein appeared to inhibit translocation of IRF3 into the nucleus. We also found that the V protein inhibited IRF3 activation when induced by a constitutive active form of IRF3. The V proteins of measles virus and Newcastle disease virus inhibited IRF3 transcriptional activation, as did the V protein of SeV, while the V proteins of mumps virus and Nipah virus did not, and inhibition by these proteins correlated with interaction of each V protein with IRF3. These results indicate that IRF3 is important as an alternative target of paramyxovirus V proteins.
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Rima BK, Duprex WP. New concepts in measles virus replication: Getting in and out in vivo and modulating the host cell environment. Virus Res 2011; 162:47-62. [DOI: 10.1016/j.virusres.2011.09.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 09/13/2011] [Accepted: 09/14/2011] [Indexed: 12/24/2022]
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Gerlier D, Lyles DS. Interplay between innate immunity and negative-strand RNA viruses: towards a rational model. Microbiol Mol Biol Rev 2011; 75:468-90, second page of table of contents. [PMID: 21885681 PMCID: PMC3165544 DOI: 10.1128/mmbr.00007-11] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The discovery of a new class of cytosolic receptors recognizing viral RNA, called the RIG-like receptors (RLRs), has revolutionized our understanding of the interplay between viruses and host cells. A tremendous amount of work has been accumulating to decipher the RNA moieties required for an RLR agonist, the signal transduction pathway leading to activation of the innate immunity orchestrated by type I interferon (IFN), the cellular and viral regulators of this pathway, and the viral inhibitors of the innate immune response. Previous reviews have focused on the RLR signaling pathway and on the negative regulation of the interferon response by viral proteins. The focus of this review is to put this knowledge in the context of the virus replication cycle within a cell. Likewise, there has been an expansion of knowledge about the role of innate immunity in the pathophysiology of viral infection. As a consequence, some discrepancies have arisen between the current models of cell-intrinsic innate immunity and current knowledge of virus biology. This holds particularly true for the nonsegmented negative-strand viruses (Mononegavirales), which paradoxically have been largely used to build presently available models. The aim of this review is to bridge the gap between the virology and innate immunity to favor the rational building of a relevant model(s) describing the interplay between Mononegavirales and the innate immune system.
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Affiliation(s)
- Denis Gerlier
- INSERM U758, CERVI, 21 avenue Tony Garnier, 69007 Lyon, France.
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