Functional Interferon System Is Required for Clearance of Lassa Virus

Yun, Nadezhda E.; Poussard, Allison; Seregin, Alexey; Walker, Aida G.; Smith, Jennifer K.; Aronson, Judith F.; Smith, Jeanon N.; Soong, Lynn; Paessler, Slobodan

doi:10.1128/jvi.06284-11

Cited by 46 publications

(52 citation statements)

References 12 publications

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“…A functional IFN system has been shown to be required for arenavirus clearance in several mouse models (37)(38)(39)(40)(41). We showed in this study that the NP RNase-defective rPICVs induced early and strong IFN responses in guinea pigs that limited virus replication in various organs (Fig.…”

Section: Discussionmentioning

confidence: 64%

In Vitro and In Vivo Characterizations of Pichinde Viral Nucleoprotein Exoribonuclease Functions

Huang

Shao

Lan

et al. 2015

J Virol

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Arenaviruses cause severe hemorrhagic fever diseases in humans, and there are limited preventative and therapeutic measures against these diseases. Previous structural and functional analyses of arenavirus nucleoproteins (NPs) revealed a conserved DEDDH exoribonuclease (RNase) domain that is important for type I interferon (IFN) suppression, but the biological roles of the NP RNase in viral replication and host immune suppression have not been well characterized. Infection of guinea pigs with Pichinde virus (PICV), a prototype arenavirus, can serve as a surrogate small animal model for arenavirus hemorrhagic fevers. In this report, we show that mutation of each of the five RNase catalytic residues of PICV NP diminishes the IFN suppression activity and slightly reduces the viral RNA replication activity. Recombinant PICVs with RNase catalytic mutations can induce high levels of IFNs and barely grow in IFN-competent A549 cells, in sharp contrast to the wild-type (WT) virus, while in IFNdeficient Vero cells, both WT and mutant viruses can replicate at relatively high levels. Upon infection of guinea pigs, the RNase mutant viruses stimulate strong IFN responses, fail to replicate productively, and can become WT revertants. Serial passages of the RNase mutants in vitro can also generate WT revertants. Thus, the NP RNase function is essential for the innate immune suppression that allows the establishment of a productive early viral infection, and it may be partly involved in the process of viral RNA replication. IMPORTANCEArenaviruses, such as Lassa, Lujo, and Machupo viruses, can cause severe and deadly hemorrhagic fever diseases in humans, and there are limited preventative and treatment options against these diseases. Development of broad-spectrum antiviral drugs depends on a better mechanistic understanding of the conserved arenavirus proteins in viral infection. The nucleoprotein (NPs) of all arenaviruses carry a unique exoribonuclease (RNase) domain that has been shown to be critical for the suppression of type I interferons. However, the functional roles of the NP RNase in arenavirus replication and host immune suppression have not been characterized systematically. Using a prototype arenavirus, Pichinde virus (PICV), we characterized the viral growth and innate immune suppression of recombinant RNase-defective mutants in both cell culture and guinea pig models. Our study suggests that the NP RNase plays an essential role in the suppression of host innate immunity, and possibly in viral RNA replication, and that it can serve as a novel target for developing antiviral drugs against arenavirus pathogens.

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Section: Discussionmentioning

confidence: 64%

In Vitro and In Vivo Characterizations of Pichinde Viral Nucleoprotein Exoribonuclease Functions

Huang

Shao

Lan

et al. 2015

J Virol

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“…In murine models knocked out for CD4, CD8, or B cell production, LASV did not induce any signs of disease. However, the inoculation of Stat-1 KO mice induced a lethal outcome in 67% of mice, indicating that the innate type I IFN response plays a major role in resistance to LASV infection in rodents and perhaps contributes to the establishment and/or maintenance of persistent infection in natural hosts (60). Recent in vitro studies implicated the arenavirus NP protein in the blocking of IFN regulatory factor 3 (IRF3), a major downstream regulator of RIG-I-inducible type I IFN responses (41,42).…”

Section: Discussionmentioning

confidence: 99%

Pathogenic Old World Arenaviruses Inhibit TLR2/Mal-Dependent Proinflammatory Cytokines In Vitro

Hayes

Carrión

Nunneley

et al. 2012

J Virol

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“…Interferon alpha/beta receptor knockout (IFNAR KO) mice (5 to 7 weeks old; 129/Sv background; obtained from the laboratory colony of Slobodan Paessler at UTMB [38]) were utilized for bioluminescence imaging on an in vivo imaging system (IVIS) at BSL-4 containment. Prior to inoculation, mice were shaved to maximize detection of the bioluminescent signal.…”

Section: Cells and Virusesmentioning

confidence: 99%

Efficient Reverse Genetics Reveals Genetic Determinants of Budding and Fusogenic Differences between Nipah and Hendra Viruses and Enables Real-Time Monitoring of Viral Spread in Small Animal Models of Henipavirus Infection

Yun

Park

Hill

et al. 2015

J Virol

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Nipah virus (NiV) and Hendra virus (HeV) are closely related henipaviruses of the Paramyxovirinae. Spillover from their fruit bat reservoirs can cause severe disease in humans and livestock. Despite their high sequence similarity, NiV and HeV exhibit apparent differences in receptor and tissue tropism, envelope-mediated fusogenicity, replicative fitness, and other pathophysiologic manifestations. To investigate the molecular basis for these differences, we first established a highly efficient reverse genetics system that increased rescue titers by >3 log units, which offset the difficulty of generating multiple recombinants under constraining biosafety level 4 (BSL-4) conditions. We then replaced, singly and in combination, the matrix (M), fusion (F), and attachment glycoprotein (G) genes in mCherry-expressing recombinant NiV (rNiV) with their HeV counterparts. These chimeric but isogenic rNiVs replicated well in primary human endothelial and neuronal cells, indicating efficient heterotypic complementation. The determinants of budding efficiency, fusogenicity, and replicative fitness were dissociable: HeV-M budded more efficiently than NiV-M, accounting for the higher replicative titers of HeV-M-bearing chimeras at early times, while the enhanced fusogenicity of NiV-G-bearing chimeras did not correlate with increased replicative fitness. Furthermore, to facilitate spatiotemporal studies on henipavirus pathogenesis, we generated a firefly luciferase-expressing NiV and monitored virus replication and spread in infected interferon alpha/beta receptor knockout mice via bioluminescence imaging. While intraperitoneal inoculation resulted in neuroinvasion following systemic spread and replication in the respiratory tract, intranasal inoculation resulted in confined spread to regions corresponding to olfactory bulbs and salivary glands before subsequent neuroinvasion. This optimized henipavirus reverse genetics system will facilitate future investigations into the growing numbers of novel henipaviruslike viruses. IMPORTANCENipah virus (NiV) and Hendra virus (HeV) are recently emergent zoonotic and highly lethal pathogens with pandemic potential. Although differences have been observed between NiV and HeV replication and pathogenesis, the molecular basis for these differences has not been examined. In this study, we established a highly efficient system to reverse engineer changes into replication-competent NiV and HeV, which facilitated the generation of reporter-expressing viruses and recombinant NiV-HeV chimeras with substitutions in the genes responsible for viral exit (the M gene, critical for assembly and budding) and viral entry (the G [attachment] and F [fusion] genes). These chimeras revealed differences in the budding and fusogenic properties of the M and G proteins, respectively, which help explain previously observed differences between NiV and HeV. Finally, to facilitate future in vivo studies, we monitored the replication and spread of a bioluminescent reporter-expressing NiV in susceptible mice; th...

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Functional Interferon System Is Required for Clearance of Lassa Virus

Cited by 46 publications

References 12 publications

In Vitro and In Vivo Characterizations of Pichinde Viral Nucleoprotein Exoribonuclease Functions

In Vitro and In Vivo Characterizations of Pichinde Viral Nucleoprotein Exoribonuclease Functions

Pathogenic Old World Arenaviruses Inhibit TLR2/Mal-Dependent Proinflammatory Cytokines In Vitro

Efficient Reverse Genetics Reveals Genetic Determinants of Budding and Fusogenic Differences between Nipah and Hendra Viruses and Enables Real-Time Monitoring of Viral Spread in Small Animal Models of Henipavirus Infection

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