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Bostedt L, Fénéant L, Leske A, Holzerland J, Günther K, Waßmann I, Bohn P, Groseth A. Alternative translation contributes to the generation of a cytoplasmic subpopulation of the Junín virus nucleoprotein that inhibits caspase activation and innate immunity. J Virol 2024; 98:e0197523. [PMID: 38294249 PMCID: PMC10878266 DOI: 10.1128/jvi.01975-23] [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: 12/19/2023] [Accepted: 01/03/2024] [Indexed: 02/01/2024] Open
Abstract
The highly pathogenic arenavirus, Junín virus (JUNV), expresses three truncated alternative isoforms of its nucleoprotein (NP), i.e., NP53kD, NP47kD, and NP40kD. While both NP47kD and NP40kD have been previously shown to be products of caspase cleavage, here, we show that expression of the third isoform NP53kD is due to alternative in-frame translation from M80. Based on this information, we were able to generate recombinant JUNVs lacking each of these isoforms. Infection with these mutants revealed that, while all three isoforms contribute to the efficient control of caspase activation, NP40kD plays the predominant role. In contrast to full-length NP (i.e., NP65kD), which is localized to inclusion bodies, where viral RNA synthesis takes place, the loss of portions of the N-terminal coiled-coil region in these isoforms leads to a diffuse cytoplasmic distribution and a loss of function in viral RNA synthesis. Nonetheless, NP53kD, NP47kD, and NP40kD all retain robust interferon antagonistic and 3'-5' exonuclease activities. We suggest that the altered localization of these NP isoforms allows them to be more efficiently targeted by activated caspases for cleavage as decoy substrates, and to be better positioned to degrade viral double-stranded (ds)RNA species that accumulate in the cytoplasm during virus infection and/or interact with cytosolic RNA sensors, thereby limiting dsRNA-mediated innate immune responses. Taken together, this work provides insight into the mechanism by which JUNV leverages apoptosis during infection to generate biologically distinct pools of NP and contributes to our understanding of the expression and biological relevance of alternative protein isoforms during virus infection.IMPORTANCEA limited coding capacity means that RNA viruses need strategies to diversify their proteome. The nucleoprotein (NP) of the highly pathogenic arenavirus Junín virus (JUNV) produces three N-terminally truncated isoforms: two (NP47kD and NP40kD) are known to be produced by caspase cleavage, while, here, we show that NP53kD is produced by alternative translation initiation. Recombinant JUNVs lacking individual NP isoforms revealed that all three isoforms contribute to inhibiting caspase activation during infection, but cleavage to generate NP40kD makes the biggest contribution. Importantly, all three isoforms retain their ability to digest double-stranded (ds)RNA and inhibit interferon promoter activation but have a diffuse cytoplasmic distribution. Given the cytoplasmic localization of both aberrant viral dsRNAs, as well as dsRNA sensors and many other cellular components of innate immune activation pathways, we suggest that the generation of NP isoforms not only contributes to evasion of apoptosis but also robust control of the antiviral response.
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Affiliation(s)
- Linus Bostedt
- Laboratory for Arenavirus Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Lucie Fénéant
- Laboratory for Arenavirus Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Anne Leske
- Laboratory for Arenavirus Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Julia Holzerland
- Laboratory for Arenavirus Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Karla Günther
- Laboratory for Arenavirus Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Irke Waßmann
- Laboratory for Arenavirus Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Patrick Bohn
- Laboratory for Arenavirus Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Allison Groseth
- Laboratory for Arenavirus Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
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2
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Zhang W, Tanneti NS, Fausto A, Nouel J, Reyes H, Weiss SR, Li Y. The vaccinia virus E3L dsRNA binding protein detects distinct production patterns of exogenous and endogenous dsRNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.21.557600. [PMID: 37790463 PMCID: PMC10542517 DOI: 10.1101/2023.09.21.557600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Double-stranded RNA (dsRNA) is a pathogen associated molecular pattern recognized by multiple pattern recognition receptors and induces innate immune responses. Viral infections can generate dsRNA during virus replication. Genetic mutations can also lead to endogenous dsRNA accumulation. DsRNA is present in multiple conformations such as the A form (A-dsRNA) or Z form (Z-dsRNA). A-dsRNA has been detected from multiple viruses with positive-stranded RNA genomes (+ssRNA) but rarely from viruses with negative RNA genomes (-RNA); Z-dsRNA can be detected from influenza virus and poxvirus infections. Viruses have evolved mechanisms to antagonize cellular antiviral responses triggered by dsRNAs. For example, the vaccinia-virus E3L protein can bind and sequester dsRNA to evade host immune responses. The E3L protein encodes a Z-DNA and a dsRNA binding domains that bind to Z-form nucleic acids or dsRNA, respectively. Here we developed recombinant E3L proteins to detect dsRNA and Z-dsRNA generated from viral infections or endogenous cellular mutations. We demonstrate that the E3L recombinant protein specifically detects A-dsRNA generated from +ssRNA viruses but not-RNA viruses. We observe that among various virus infections assayed, only the influenza A virus generates Z-RNA that can be detected by anti-Z-NA antibody but not by the E3L recombinant protein containing the Z-DNA domain. The E3L recombinant protein can also detect endogenous dsRNA in PNPT1 or SUV3L1 knockout cells. Together we concluded that A-dsRNA can be produced and detected from viruses with +ssRNA genomes but not-RNA genomes, and Z-dsRNA can be produced and detected from influenza A virus. Importance The detection of dsRNAs, which exist in the A-dsRNA or Z-RNA conformation, is important for the induction of innate immune responses. dsRNA are generated during a virus infection due to virus replication, or can accumulate to genetic mutations. We engineered recombinant vaccinia virus E3L protein that can detect A-dsRNA generated during infection with a positive-sense RNA genome virus but not a negative-sense RNA genome virus. Infection with influenza A virus generates Z-RNA that can be detected with an anti-z-antibody but not the E3L recombinant protein. The E3L recombinant protein also detects endogenous dsRNA in PNPT1 or SUV3L knockout cells. These findings highlight important characteristics of dsRNA structure and detection.
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3
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Sierra AA, Loureiro ME, Esperante S, Borkosky SS, Gallo GL, de Prat Gay G, Lopez N. Nuclease Activity of the Junín Virus Nucleoprotein C-Terminal Domain. Viruses 2023; 15:1818. [PMID: 37766225 PMCID: PMC10535676 DOI: 10.3390/v15091818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/18/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023] Open
Abstract
The mammarenavirus Junín (JUNV) is the causative agent of Argentine hemorrhagic fever, a severe disease of public health concern. The most abundant viral protein is the nucleoprotein (NP), a multifunctional, two-domain protein with the primary role as structural component of the viral nucleocapsids, used as template for viral polymerase RNA synthesis activities. Here, we report that the C-terminal domain (CTD) of the attenuated Candid#1 strain of the JUNV NP can be purified as a stable soluble form with a secondary structure in line with known NP structures from other mammarenaviruses. We show that the JUNV NP CTD interacts with the viral matrix protein Z in vitro, and that the full-length NP and Z interact with each other in cellulo, suggesting that the NP CTD is responsible for this interaction. This domain comprises an arrangement of four acidic residues and a histidine residue conserved in the active site of exoribonucleases belonging to the DEDDh family. We show that the JUNV NP CTD displays metal-ion-dependent nuclease activity against DNA and single- and double-stranded RNA, and that this activity is impaired by the mutation of a catalytic residue within the DEDDh motif. These results further support this activity, not previously observed in the JUNV NP, which could impact the mechanism of the cellular immune response modulation of this important pathogen.
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Affiliation(s)
- Alicia Armella Sierra
- Centro de Virología Humana y Animal (CEVHAN), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Abierta Interamericana, Buenos Aires C1287, Argentina; (A.A.S.); (M.E.L.); (G.L.G.)
| | - María Eugenia Loureiro
- Centro de Virología Humana y Animal (CEVHAN), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Abierta Interamericana, Buenos Aires C1287, Argentina; (A.A.S.); (M.E.L.); (G.L.G.)
| | - Sebastián Esperante
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires C1405, Argentina; (S.E.); (S.S.B.); (G.d.P.G.)
| | - Silvia Susana Borkosky
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires C1405, Argentina; (S.E.); (S.S.B.); (G.d.P.G.)
| | - Giovanna L. Gallo
- Centro de Virología Humana y Animal (CEVHAN), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Abierta Interamericana, Buenos Aires C1287, Argentina; (A.A.S.); (M.E.L.); (G.L.G.)
| | - Gonzalo de Prat Gay
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) CONICET, Buenos Aires C1405, Argentina; (S.E.); (S.S.B.); (G.d.P.G.)
| | - Nora Lopez
- Centro de Virología Humana y Animal (CEVHAN), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Abierta Interamericana, Buenos Aires C1287, Argentina; (A.A.S.); (M.E.L.); (G.L.G.)
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4
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Boccaccio GL, Thomas MG, García CC. Membraneless Organelles and Condensates Orchestrate Innate Immunity Against Viruses. J Mol Biol 2023; 435:167976. [PMID: 36702393 DOI: 10.1016/j.jmb.2023.167976] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/10/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023]
Abstract
The cellular defense against viruses involves the assembly of oligomers, granules and membraneless organelles (MLOs) that govern the activation of several arms of the innate immune response. Upon interaction with specific pathogen-derived ligands, a number of pattern recognition receptors (PRRs) undergo phase-separation thus triggering downstream signaling pathways. Among other relevant condensates, inflammasomes, apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) specks, cyclic GMP-AMP synthase (cGAS) foci, protein kinase R (PKR) clusters, ribonuclease L-induced bodies (RLBs), stress granules (SGs), processing bodies (PBs) and promyelocytic leukemia protein nuclear bodies (PML NBs) play different roles in the immune response. In turn, viruses have evolved diverse strategies to evade the host defense. Viral DNA or RNA, as well as viral proteases or proteins carrying intrinsically disordered regions may interfere with condensate formation and function in multiple ways. In this review we discuss current and hypothetical mechanisms of viral escape that involve the disassembly, repurposing, or inactivation of membraneless condensates that govern innate immunity. We summarize emerging interconnections between these diverse condensates that ultimately determine the cellular outcome.
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Affiliation(s)
- Graciela Lidia Boccaccio
- Laboratorio de Biología Celular del ARN, Instituto Leloir (FIL) and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) - Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina; Departamento de Fisiología y Biología Molecular y Celular (FBMyC), Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - María Gabriela Thomas
- Laboratorio de Biología Celular del ARN, Instituto Leloir (FIL) and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA) - Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina. https://www.twitter.com/_gabithomas
| | - Cybele Carina García
- Departamento de Química Biológica (QB), Facultad de Ciencias Exactas y Naturales (FCEN), and IQUIBICEN, Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET) and Universidad de Buenos Aires, Buenos Aires, Argentina
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5
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Coy SR, Utama B, Spurlin JW, Kim JG, Deshmukh H, Lwigale P, Nagasaki K, Correa AMS. Visualization of RNA virus infection in a marine protist with a universal biomarker. Sci Rep 2023; 13:5813. [PMID: 37037845 PMCID: PMC10086069 DOI: 10.1038/s41598-023-31507-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/13/2023] [Indexed: 04/12/2023] Open
Abstract
Half of the marine virosphere is hypothesized to be RNA viruses (kingdom Orthornavirae) that infect abundant micro-eukaryotic hosts (e.g. protists). To test this, quantitative approaches that broadly track infections in situ are needed. Here, we describe a technique-dsRNA-Immunofluorescence (dsRIF)-that uses a double-stranded RNA (dsRNA) targeting monoclonal antibody to assess host infection status based on the presence of dsRNA, a replicative intermediate of all Orthornavirae infections. We show that the dinoflagellate Heterocapsa circularisquama produces dsRIF signal ~ 1000 times above background autofluorescence when infected by the + ssRNA virus HcRNAV. dsRNA-positive virocells were detected across > 50% of the 48-h infection cycle and accumulated to represent at least 63% of the population. Photosynthetic and chromosomal integrity remained intact during peak replication, indicating HcRNAV infection does not interrupt these processes. This work validates the use of dsRIF on marine RNA viruses and their hosts, setting the stage for quantitative environmental applications that will accelerate understanding of virus-driven ecosystem impacts.
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Affiliation(s)
- Samantha R Coy
- Department of Biosciences, Rice University, Houston, TX, USA.
- Department of Oceanography, Texas A&M University, College Station, TX, USA.
| | - Budi Utama
- Shared Equipment Authority, Rice University, Houston, TX, USA
| | - James W Spurlin
- Department of Biosciences, Rice University, Houston, TX, USA
| | - Julia G Kim
- Department of Biosciences, Rice University, Houston, TX, USA
| | | | - Peter Lwigale
- Department of Biosciences, Rice University, Houston, TX, USA
| | - Keizo Nagasaki
- Faculty of Science and Technology, Kochi University, Nankoku, Kochi, 783-8502, Japan
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6
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Thomsen C, Røge R, Fred Å, Wanders A. Immunohistochemical detection of double-stranded RNA in formalin-fixed paraffin-embedded tissue. APMIS 2023; 131:197-205. [PMID: 36776120 DOI: 10.1111/apm.13300] [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: 10/12/2022] [Accepted: 02/05/2023] [Indexed: 02/14/2023]
Abstract
Double-stranded RNA (dsRNA) is produced during most viral infections, and immunohistochemical detection of dsRNA has been proposed as a potential screening marker for viral replication. The anti-dsRNA monoclonal antibody clone 9D5 is more sensitive than the established clone J2 but has not been validated in formalin-fixed paraffin-embedded (FFPE) tissue. This study aimed to test and compare the performance of the anti-dsRNA monoclonal antibodies, 9D5 and J2, in FFPE tissue using an automated staining platform. Archived clinical tissue samples with viral infections (n = 34) and uninfected controls (n = 30) were examined. Immunohistochemical staining for dsRNA (9D5 and J2) and virus-specific epitopes was performed. 9D5 provided a similar staining pattern but a higher signal-to-noise ratio than J2. The following proportions of virus-infected tissue samples were dsRNA-positive: SARS-CoV-2 (5/5), HPV (6/6), MCV (5/5), CMV (5/6), HSV (4/6), and EBV (0/6). Also, 18 of 30 uninfected samples were dsRNA positive, and an association between fixation time and intensity was observed. However, signals in all samples were markedly reduced by pretreatment with dsRNA-specific RNAse-III, indicating a specific reaction. In conclusion, dsRNA can be demonstrated in most viral infections with immunohistochemistry in FFPE tissue but with low clinical specificity. The antibody clone 9D5 performs better than clone J2.
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Affiliation(s)
- Christian Thomsen
- Department of Pathology, Aalborg University Hospital, Aalborg, Denmark.,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Rasmus Røge
- Department of Pathology, Aalborg University Hospital, Aalborg, Denmark.,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Åsa Fred
- Department of Pathology, Halmstad Hospital, Halmstad, Sweden.,Department of Pathology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Alkwin Wanders
- Department of Pathology, Aalborg University Hospital, Aalborg, Denmark.,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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7
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Bohn P, Waßmann I, Wendt L, Leske A, Hoenen T, Tews BA, Groseth A. A dsRNA-binding mutant reveals only a minor role of exonuclease activity in interferon antagonism by the arenavirus nucleoprotein. PLoS Pathog 2023; 19:e1011049. [PMID: 36603036 PMCID: PMC9815661 DOI: 10.1371/journal.ppat.1011049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 12/07/2022] [Indexed: 01/06/2023] Open
Abstract
The arenavirus nucleoprotein (NP) plays an important role in the virus' ability to block interferon (IFN) production, and its exonuclease function appears to contribute to this activity. However, efforts to analyze this contribution are complicated by the functional overlap between the exonuclease active site and a neighboring region involved in IKKε-binding and subsequent inhibition of IRF3 activation, which also plays an important role in IFN production. To circumvent this issue, we mutated a residue located away from the active site that is involved in binding of the dsRNA substrate being targeted for exonuclease digestion, i.e. H426A. We found that expression of Tacaribe virus (TCRV) NP containing this RNA-binding H426A mutation was still able to efficiently block IFN-β promoter activity in response to Sendai virus infection, despite being strongly impaired in its exonuclease activity. This was in contrast to a conventional exonuclease active site mutant (E388A), which was impaired with respect to both exonuclease activity and IFN antagonism. Importantly, growth of a recombinant virus encoding the RNA-binding mutation (rTCRV-H426A) was similar to wild-type in IFN-deficient cells, unlike the active site mutant (rTCRV-E388A), which was already markedly impaired in these cells. Further, in IFN-competent cells, the TCRV-H426A RNA-binding mutant showed more robust growth and delayed IFN-β mRNA upregulation compared to the TCRV-E388A active site mutant. Taken together, this novel mutational approach, which allows us to now dissect the different contributions of the NP exonuclease activity and IKKε-binding/IRF3 inhibition to IFN antagonism, clearly suggests that conventional exonuclease mutants targeting the active site overestimate the contribution of the exonuclease function, and that rather other IFN antagonistic functions of NP play the dominant role in IFN-antagonism.
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Affiliation(s)
- Patrick Bohn
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Irke Waßmann
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Lisa Wendt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Anne Leske
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Thomas Hoenen
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Birke A. Tews
- Institute of Infectology, Friedrich-Loeffler-Institut, Greifswald–Insel Riems, Germany
| | - Allison Groseth
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
- * E-mail:
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8
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Małkowska P, Niedźwiedzka-Rystwej P. Factors affecting RIG-I-Like receptors activation - New research direction for viral hemorrhagic fevers. Front Immunol 2022; 13:1010635. [PMID: 36248895 PMCID: PMC9557057 DOI: 10.3389/fimmu.2022.1010635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Viral hemorrhagic fever (VHF) is a term referring to a group of life-threatening infections caused by several virus families (Arenaviridae, Bunyaviridae, Filoviridae and Flaviviridae). Depending on the virus, the infection can be mild and can be also characterized by an acute course with fever accompanied by hypervolemia and coagulopathy, resulting in bleeding and shock. It has been suggested that the course of the disease is strongly influenced by the activation of signaling pathways leading to RIG-I-like receptor-dependent interferon production. RIG-I-like receptors (RLRs) are one of two major receptor families that detect viral nucleic acid. RLR receptor activation is influenced by a number of factors that may have a key role in the differences that occur during the antiviral immune response in VHF. In the present study, we collected data on RLR receptors in viral hemorrhagic fevers and described factors that may influence the activation of the antiviral response. RLR receptors seem to be a good target for VHF research, which may contribute to better therapeutic and diagnostic strategies. However, due to the difficulty of conducting such studies in humans, we suggest using Lagovirus europaeus as an animal model for VHF.
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Affiliation(s)
- Paulina Małkowska
- Doctoral School, University of Szczecin, Szczecin, Poland
- Institute of Biology, University of Szczecin, Szczecin, Poland
- *Correspondence: Paulina Małkowska,
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9
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Gallo GL, López N, Loureiro ME. The Virus–Host Interplay in Junín Mammarenavirus Infection. Viruses 2022; 14:v14061134. [PMID: 35746604 PMCID: PMC9228484 DOI: 10.3390/v14061134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 02/06/2023] Open
Abstract
Junín virus (JUNV) belongs to the Arenaviridae family and is the causative agent of Argentine hemorrhagic fever (AHF), a severe human disease endemic to agricultural areas in Argentina. At this moment, there are no effective antiviral therapeutics to battle pathogenic arenaviruses. Cumulative reports from recent years have widely provided information on cellular factors playing key roles during JUNV infection. In this review, we summarize research on host molecular determinants that intervene in the different stages of the viral life cycle: viral entry, replication, assembly and budding. Alongside, we describe JUNV tight interplay with the innate immune system. We also review the development of different reverse genetics systems and their use as tools to study JUNV biology and its close teamwork with the host. Elucidating relevant interactions of the virus with the host cell machinery is highly necessary to better understand the mechanistic basis beyond virus multiplication, disease pathogenesis and viral subversion of the immune response. Altogether, this knowledge becomes essential for identifying potential targets for the rational design of novel antiviral treatments to combat JUNV as well as other pathogenic arenaviruses.
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10
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Price AM, Steinbock RT, Di C, Hayer KE, Li Y, Herrmann C, Parenti NA, Whelan JN, Weiss SR, Weitzman MD. Adenovirus prevents dsRNA formation by promoting efficient splicing of viral RNA. Nucleic Acids Res 2021; 50:1201-1220. [PMID: 34671803 PMCID: PMC8860579 DOI: 10.1093/nar/gkab896] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/10/2021] [Accepted: 10/08/2021] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cells recognize intracellular pathogens through pattern recognition receptors, including sensors of aberrant nucleic acid structures. Sensors of double-stranded RNA (dsRNA) are known to detect replication intermediates of RNA viruses. It has long been suggested that annealing of mRNA from symmetrical transcription of both top and bottom strands of DNA virus genomes can produce dsRNA during infection. Supporting this hypothesis, nearly all DNA viruses encode inhibitors of dsRNA-recognition pathways. However, direct evidence that DNA viruses produce dsRNA is lacking. Contrary to dogma, we show that the nuclear-replicating DNA virus adenovirus (AdV) does not produce detectable levels of dsRNA during infection. In contrast, abundant dsRNA is detected within the nucleus of cells infected with AdV mutants defective for viral RNA processing. In the presence of nuclear dsRNA, the cytoplasmic dsRNA sensor PKR is relocalized and activated within the nucleus. Accumulation of viral dsRNA occurs in the late phase of infection, when unspliced viral transcripts form intron/exon base pairs between top and bottom strand transcripts. We propose that DNA viruses actively limit dsRNA formation by promoting efficient splicing and mRNA processing, thus avoiding detection and restriction by host innate immune sensors of pathogenic nucleic acids.
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Affiliation(s)
- Alexander M Price
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Robert T Steinbock
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Cell & Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Chao Di
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Katharina E Hayer
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Yize Li
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christin Herrmann
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Cell & Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Nicholas A Parenti
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jillian N Whelan
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Susan R Weiss
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew D Weitzman
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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11
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Thoresen D, Wang W, Galls D, Guo R, Xu L, Pyle AM. The molecular mechanism of RIG-I activation and signaling. Immunol Rev 2021; 304:154-168. [PMID: 34514601 PMCID: PMC9293153 DOI: 10.1111/imr.13022] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/10/2021] [Accepted: 08/17/2021] [Indexed: 12/25/2022]
Abstract
RIG‐I is our first line of defense against RNA viruses, serving as a pattern recognition receptor that identifies molecular features common among dsRNA and ssRNA viral pathogens. RIG‐I is maintained in an inactive conformation as it samples the cellular space for pathogenic RNAs. Upon encounter with the triphosphorylated terminus of blunt‐ended viral RNA duplexes, the receptor changes conformation and releases a pair of signaling domains (CARDs) that are selectively modified and interact with an adapter protein (MAVS), thereby triggering a signaling cascade that stimulates transcription of interferons. Here, we describe the structural determinants for specific RIG‐I activation by viral RNA, and we describe the strategies by which RIG‐I remains inactivated in the presence of host RNAs. From the initial RNA triggering event to the final stages of interferon expression, we describe the experimental evidence underpinning our working knowledge of RIG‐I signaling. We draw parallels with behavior of related proteins MDA5 and LGP2, describing evolutionary implications of their collective surveillance of the cell. We conclude by describing the cell biology and immunological investigations that will be needed to accurately describe the role of RIG‐I in innate immunity and to provide the necessary foundation for pharmacological manipulation of this important receptor.
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Affiliation(s)
- Daniel Thoresen
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Wenshuai Wang
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Drew Galls
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Rong Guo
- Chemistry, Yale University, New Haven, CT, USA
| | - Ling Xu
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Anna Marie Pyle
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.,Chemistry, Yale University, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
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12
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The Protein Kinase Receptor Modulates the Innate Immune Response against Tacaribe Virus. Viruses 2021; 13:v13071313. [PMID: 34372519 PMCID: PMC8310291 DOI: 10.3390/v13071313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022] Open
Abstract
The New World (NW) mammarenavirus group includes several zoonotic highly pathogenic viruses, such as Junin (JUNV) or Machupo (MACV). Contrary to the Old World mammarenavirus group, these viruses are not able to completely suppress the innate immune response and trigger a robust interferon (IFN)-I response via retinoic acid-inducible gene I (RIG-I). Nevertheless, pathogenic NW mammarenaviruses trigger a weaker IFN response than their nonpathogenic relatives do. RIG-I activation leads to upregulation of a plethora of IFN-stimulated genes (ISGs), which exert a characteristic antiviral effect either as lone effectors, or resulting from the combination with other ISGs or cellular factors. The dsRNA sensor protein kinase receptor (PKR) is an ISG that plays a pivotal role in the control of the mammarenavirus infection. In addition to its well-known protein synthesis inhibition, PKR further modulates the overall IFN-I response against different viruses, including mammarenaviruses. For this study, we employed Tacaribe virus (TCRV), the closest relative of the human pathogenic JUNV. Our findings indicate that PKR does not only increase IFN-I expression against TCRV infection, but also affects the kinetic expression and the extent of induction of Mx1 and ISG15 at both levels, mRNA and protein expression. Moreover, TCRV fails to suppress the effect of activated PKR, resulting in the inhibition of a viral titer. Here, we provide original evidence of the specific immunomodulatory role of PKR over selected ISGs, altering the dynamic of the innate immune response course against TCRV. The mechanisms for innate immune evasion are key for the emergence and adaptation of human pathogenic arenaviruses, and highly pathogenic mammarenaviruses, such as JUNV or MACV, trigger a weaker IFN response than nonpathogenic mammarenaviruses. Within the innate immune response context, PKR plays an important role in sensing and restricting the infection of TCRV virus. Although the mechanism of PKR for protein synthesis inhibition is well described, its immunomodulatory role is less understood. Our present findings further characterize the innate immune response in the absence of PKR, unveiling the role of PKR in defining the ISG profile after viral infection. Moreover, TCRV fails to suppress activated PKR, resulting in viral progeny production inhibition.
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13
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Distinct Molecular Mechanisms of Host Immune Response Modulation by Arenavirus NP and Z Proteins. Viruses 2020; 12:v12070784. [PMID: 32708250 PMCID: PMC7412275 DOI: 10.3390/v12070784] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 12/12/2022] Open
Abstract
Endemic to West Africa and South America, mammalian arenaviruses can cross the species barrier from their natural rodent hosts to humans, resulting in illnesses ranging from mild flu-like syndromes to severe and fatal haemorrhagic zoonoses. The increased frequency of outbreaks and associated high fatality rates of the most prevalent arenavirus, Lassa, in West African countries, highlights the significant risk to public health and to the socio-economic development of affected countries. The devastating impact of these viruses is further exacerbated by the lack of approved vaccines and effective treatments. Differential immune responses to arenavirus infections that can lead to either clearance or rapid, widespread and uncontrolled viral dissemination are modulated by the arenavirus multifunctional proteins, NP and Z. These two proteins control the antiviral response to infection by targeting multiple cellular pathways; and thus, represent attractive targets for antiviral development to counteract infection. The interplay between the host immune responses and viral replication is a key determinant of virus pathogenicity and disease outcome. In this review, we examine the current understanding of host immune defenses against arenavirus infections and summarise the host protein interactions of NP and Z and the mechanisms that govern immune evasion strategies.
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14
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Mateer EJ, Maruyama J, Card GE, Paessler S, Huang C. Lassa Virus, but Not Highly Pathogenic New World Arenaviruses, Restricts Immunostimulatory Double-Stranded RNA Accumulation during Infection. J Virol 2020; 94:e02006-19. [PMID: 32051278 PMCID: PMC7163147 DOI: 10.1128/jvi.02006-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/09/2020] [Indexed: 12/14/2022] Open
Abstract
The arenaviruses Lassa virus (LASV), Junín virus (JUNV), and Machupo virus (MACV) can cause severe and fatal diseases in humans. Although these pathogens are closely related, the host immune responses to these virus infections differ remarkably, with direct implications for viral pathogenesis. LASV infection is immunosuppressive, with a very low-level interferon response. In contrast, JUNV and MACV infections stimulate a robust interferon (IFN) response in a retinoic acid-inducible gene I (RIG-I)-dependent manner and readily activate protein kinase R (PKR), a known host double-stranded RNA (dsRNA) sensor. In response to infection with RNA viruses, host nonself RNA sensors recognize virus-derived dsRNA as danger signals and initiate innate immune responses. Arenavirus nucleoproteins (NPs) contain a highly conserved exoribonuclease (ExoN) motif, through which LASV NP has been shown to degrade virus-derived immunostimulatory dsRNA in biochemical assays. In this study, we for the first time present evidence that LASV restricts dsRNA accumulation during infection. Although JUNV and MACV NPs also have the ExoN motif, dsRNA readily accumulated in infected cells and often colocalized with dsRNA sensors. Moreover, LASV coinfection diminished the accumulation of dsRNA and the IFN response in JUNV-infected cells. The disruption of LASV NP ExoN with a mutation led to dsRNA accumulation and impaired LASV replication in minigenome systems. Importantly, both LASV NP and RNA polymerase L protein were required to diminish the accumulation of dsRNA and the IFN response in JUNV infection. For the first time, we discovered a collaboration between LASV NP ExoN and L protein in limiting dsRNA accumulation. Our new findings provide mechanistic insights into the differential host innate immune responses to highly pathogenic arenavirus infections.IMPORTANCE Arenavirus NPs contain a highly conserved DEDDh ExoN motif, through which LASV NP degrades virus-derived, immunostimulatory dsRNA in biochemical assays to eliminate the danger signal and inhibit the innate immune response. Nevertheless, the function of NP ExoN in arenavirus infection remains to be defined. In this study, we discovered that LASV potently restricts dsRNA accumulation during infection and minigenome replication. In contrast, although the NPs of JUNV and MACV also harbor the ExoN motif, dsRNA readily formed during JUNV and MACV infections, accompanied by IFN and PKR responses. Interestingly, LASV NP alone was not sufficient to limit dsRNA accumulation. Instead, both LASV NP and L protein were required to restrict immunostimulatory dsRNA accumulation. Our findings provide novel and important insights into the mechanism for the distinct innate immune response to these highly pathogenic arenaviruses and open new directions for future studies.
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Affiliation(s)
- Elizabeth J Mateer
- Department of Pathology, Galveston National Laboratory and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
| | - Junki Maruyama
- Department of Pathology, Galveston National Laboratory and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
| | - Galen E Card
- Department of Pathology, Galveston National Laboratory and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
| | - Slobodan Paessler
- Department of Pathology, Galveston National Laboratory and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
| | - Cheng Huang
- Department of Pathology, Galveston National Laboratory and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
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15
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Gaete-Argel A, Márquez CL, Barriga GP, Soto-Rifo R, Valiente-Echeverría F. Strategies for Success. Viral Infections and Membraneless Organelles. Front Cell Infect Microbiol 2019; 9:336. [PMID: 31681621 PMCID: PMC6797609 DOI: 10.3389/fcimb.2019.00336] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/18/2019] [Indexed: 12/12/2022] Open
Abstract
Regulation of RNA homeostasis or “RNAstasis” is a central step in eukaryotic gene expression. From transcription to decay, cellular messenger RNAs (mRNAs) associate with specific proteins in order to regulate their entire cycle, including mRNA localization, translation and degradation, among others. The best characterized of such RNA-protein complexes, today named membraneless organelles, are Stress Granules (SGs) and Processing Bodies (PBs) which are involved in RNA storage and RNA decay/storage, respectively. Given that SGs and PBs are generally associated with repression of gene expression, viruses have evolved different mechanisms to counteract their assembly or to use them in their favor to successfully replicate within the host environment. In this review we summarize the current knowledge about the viral regulation of SGs and PBs, which could be a potential novel target for the development of broad-spectrum antiviral therapies.
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Affiliation(s)
- Aracelly Gaete-Argel
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,HIV/AIDS Workgroup, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Chantal L Márquez
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,HIV/AIDS Workgroup, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Gonzalo P Barriga
- Emerging Viruses Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Ricardo Soto-Rifo
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,HIV/AIDS Workgroup, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Fernando Valiente-Echeverría
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,HIV/AIDS Workgroup, Faculty of Medicine, Universidad de Chile, Santiago, Chile
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16
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Differential Immune Responses to Hemorrhagic Fever-Causing Arenaviruses. Vaccines (Basel) 2019; 7:vaccines7040138. [PMID: 31581720 PMCID: PMC6963578 DOI: 10.3390/vaccines7040138] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/25/2019] [Accepted: 09/30/2019] [Indexed: 12/28/2022] Open
Abstract
The family Arenaviridae contains several pathogens of major clinical importance. The Old World (OW) arenavirus Lassa virus is endemic in West Africa and is estimated to cause up to 300,000 infections each year. The New World (NW) arenaviruses Junín and Machupo periodically cause hemorrhagic fever outbreaks in South America. While these arenaviruses are highly pathogenic in humans, recent evidence indicates that pathogenic OW and NW arenaviruses interact with the host immune system differently, which may have differential impacts on viral pathogenesis. Severe Lassa fever cases are characterized by profound immunosuppression. In contrast, pathogenic NW arenavirus infections are accompanied by elevated levels of Type I interferon and pro-inflammatory cytokines. This review aims to summarize recent findings about interactions of these pathogenic arenaviruses with the innate immune machinery and the subsequent effects on adaptive immunity, which may inform the development of vaccines and therapeutics against arenavirus infections.
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17
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Comparison of the Innate Immune Responses to Pathogenic and Nonpathogenic Clade B New World Arenaviruses. J Virol 2019; 93:JVI.00148-19. [PMID: 31270228 DOI: 10.1128/jvi.00148-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/28/2019] [Indexed: 12/25/2022] Open
Abstract
The New World (NW) arenaviruses are a diverse group of zoonotic viruses, including several causative agents of severe hemorrhagic fevers in humans. All known human-pathogenic NW arenaviruses belong to clade B, where they group into sublineages with phylogenetically closely related nonpathogenic viruses, e.g., the highly pathogenic Junin (JUNV) and Machupo viruses with the nonpathogenic Tacaribe virus (TCRV). Considering the close genetic relationship of nonpathogenic and pathogenic NW arenaviruses, the identification of molecular determinants of virulence is of great importance. The host cell's innate antiviral defense represents a major barrier for zoonotic infection. Here, we performed a side-by-side comparison of the innate immune responses against JUNV and TCRV in human cells. Despite similar levels of viral replication, infection with TCRV consistently induced a stronger type I interferon (IFN-I) response than JUNV infection did. Transcriptome profiling revealed upregulation of a largely overlapping set of interferon-stimulated genes in cells infected with TCRV and JUNV. Both viruses were relatively insensitive to IFN-I treatment of human cells and induced similar levels of apoptosis in the presence or absence of an IFN-I response. However, in comparison to JUNV, TCRV induced stronger activation of the innate sensor double-strand RNA-dependent protein kinase R (PKR), resulting in phosphorylation of eukaryotic translation initiation factor eIF2α. Confocal microscopy studies revealed similar subcellular colocalizations of the JUNV and TCRV viral replication-transcription complexes with PKR. However, deletion of PKR by CRISPR/Cas9 hardly affected JUNV but promoted TCRV multiplication, providing the first evidence for differential innate recognition and control of pathogenic and nonpathogenic NW arenaviruses by PKR.IMPORTANCE New World (NW) arenaviruses are a diverse family of emerging zoonotic viruses that merit significant attention as important public health problems. The close genetic relationship of nonpathogenic NW arenaviruses with their highly pathogenic cousins suggests that few mutations may be sufficient to enhance virulence. The identification of molecular determinants of virulence of NW arenaviruses is therefore of great importance. Here we undertook a side-by-side comparison of the innate immune responses against the highly pathogenic Junin virus (JUNV) and the related nonpathogenic Tacaribe virus (TCRV) in human cells. We consistently found that TCRV induces a stronger type I interferon (IFN-I) response than JUNV. Transcriptome profiling revealed an overlapping pattern of IFN-induced gene expression and similar low sensitivities to IFN-I treatment. However, the double-stranded RNA (dsRNA)-dependent protein kinase R (PKR) contributed to the control of TCRV, but not JUNV, providing the first evidence for differential innate recognition and control of JUNV and TCRV.
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18
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Brisse ME, Ly H. Hemorrhagic Fever-Causing Arenaviruses: Lethal Pathogens and Potent Immune Suppressors. Front Immunol 2019; 10:372. [PMID: 30918506 PMCID: PMC6424867 DOI: 10.3389/fimmu.2019.00372] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 02/14/2019] [Indexed: 12/22/2022] Open
Abstract
Hemorrhagic fevers (HF) resulting from pathogenic arenaviral infections have traditionally been neglected as tropical diseases primarily affecting African and South American regions. There are currently no FDA-approved vaccines for arenaviruses, and treatments have been limited to supportive therapy and use of non-specific nucleoside analogs, such as Ribavirin. Outbreaks of arenaviral infections have been limited to certain geographic areas that are endemic but known cases of exportation of arenaviruses from endemic regions and socioeconomic challenges for local control of rodent reservoirs raise serious concerns about the potential for larger outbreaks in the future. This review synthesizes current knowledge about arenaviral evolution, ecology, transmission patterns, life cycle, modulation of host immunity, disease pathogenesis, as well as discusses recent development of preventative and therapeutic pursuits against this group of deadly viral pathogens.
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Affiliation(s)
- Morgan E Brisse
- Biochemistry, Molecular Biology, and Biophysics Graduate Program, University of Minnesota, St. Paul, MN, United States.,Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, United States
| | - Hinh Ly
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, United States
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19
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Mateer E, Paessler S, Huang C. Confocal Imaging of Double-Stranded RNA and Pattern Recognition Receptors in Negative-Sense RNA Virus Infection. J Vis Exp 2019. [PMID: 30741258 DOI: 10.3791/59095] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Double-stranded (ds) RNA is produced as a replicative intermediate during RNA virus infection. Recognition of dsRNA by host pattern recognition receptors (PRRs) such as the retinoic acid (RIG-I) like receptors (RLRs) RIG-I and melanoma differentiation-associated protein 5 (MDA-5) leads to the induction of the innate immune response. The formation and intracellular distribution of dsRNA in positive-sense RNA virus infection has been well characterized by microscopy. Many negative-sense RNA viruses, including some arenaviruses, trigger the innate immune response during infection. However, negative-sense RNA viruses were thought to produce low levels of dsRNA, which hinders the imaging study of PRR recognition of viral dsRNA. Additionally, infection experiments with highly pathogenic arenaviruses must be performed in high containment biosafety level facilities (BSL-4). The interaction between viral RNA and PRRs for highly pathogenic RNA virus is largely unknown due to the additional technical challenges that researchers need to face in the BSL-4 facilities. Recently, a monoclonal antibody (Mab) (clone 9D5) originally used for pan-enterovirus detection has been found to specifically detect dsRNA with a higher sensitivity than the traditional J2 or K1 anti-dsRNA antibodies. Herein, by utilizing the 9D5 antibody, we describe a confocal microscopy protocol that has been used successfully to visualize dsRNA, viral protein and PRR simultaneously in individual cells infected by arenavirus. The protocol is also suitable for imaging studies of dsRNA and PRR distribution in pathogenic arenavirus infected cells in BSL4 facilities.
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Affiliation(s)
- Elizabeth Mateer
- Department of Pathology and Institute for Human Infections and Immunity, University of Texas Medical Branch;
| | - Slobodan Paessler
- Department of Pathology and Institute for Human Infections and Immunity, University of Texas Medical Branch
| | - Cheng Huang
- Department of Pathology and Institute for Human Infections and Immunity, University of Texas Medical Branch
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