#Junin Virus Triggers #Macrophage Activation and Modulates Polarization According to Viral Strain #Pathogenicity (Front Immunol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Front Immunol. 2019 Oct 22;10:2499. doi: 10.3389/fimmu.2019.02499. eCollection 2019.

Junin Virus Triggers Macrophage Activation and Modulates Polarization According to Viral Strain Pathogenicity.

Ferrer MF1, Thomas P1, López Ortiz AO1,2, Errasti AE3, Charo N2, Romanowski V1,4, Gorgojo J5, Rodriguez ME5, Carrera Silva EA2, Gómez RM1,4.

Author information: 1 Laboratorio de Virus Animales, Instituto de Biotecnología y Biología Molecular, CONICET-Universidad Nacional de La Plata, La Plata, Argentina. 2 Laboratorio de Trombosis Experimental, Instituto de Medicina Experimental, CONICET-Academia Nacional de Medicina, Buenos Aires, Argentina. 3 Facultad de Medicina, Instituto de Farmacologia, University of Buenos Aries, Buenos Aires, Argentina. 4 Global Viral Network, Baltimore, MD, United States. 5 Centro de Investigación y Desarrollo en Fermentaciones Industriales, CONICET-Universidad Nacional de La Plata, La Plata, Argentina.

 

Abstract

The New World arenavirus Junin (JUNV) is the etiological agent of Argentine hemorrhagic fever (AHF). Previous studies of human macrophage infection by the Old-World arenaviruses Mopeia and Lassa showed that while the non-pathogenic Mopeia virus replicates and activates human macrophages, the pathogenic Lassa virus replicates but fails to activate human macrophages. Less is known in regard to the impact of New World arenavirus infection on the human macrophage immune response. Macrophage activation is critical for controlling infections but could also be usurped favoring immune evasion. Therefore, it is crucial to understand how the JUNV infection modulates macrophage plasticity to clarify its role in AHF pathogenesis. With this aim in mind, we compared infection with the attenuated Candid 1 (C#1) or the pathogenic P strains of the JUNV virus in human macrophage cultures. The results showed that both JUNV strains similarly replicated and induced morphological changes as early as 1 day post-infection. However, both strains differentially induced the expression of CD71, the receptor for cell entry, the activation and maturation molecules CD80, CD86, and HLA-DR and selectively modulated cytokine production. Higher levels of TNF-α, IL-10, and IL-12 were detected with C#1 strain, while the P strain induced only higher levels of IL-6. We also found that C#1 strain infection skewed macrophage polarization to M1, whereas the P strain shifted the response to an M2 phenotype. Interestingly, the MERTK receptor, that negatively regulates the immune response, was down-regulated by C#1 strain and up-regulated by P strain infection. Similarly, the target genes of MERTK activation, the cytokine suppressors SOCS1 and SOCS3, were also increased after P strain infection, in addition to IRF-1, that regulates type I IFN levels, which were higher with C#1 compared with P strain infection. Together, this differential activation/polarization pattern of macrophages elicited by P strain suggests a more evasive immune response and may have important implications in the pathogenesis of AHF and underpinning the development of new potential therapeutic strategies.

Copyright © 2019 Ferrer, Thomas, López Ortiz, Errasti, Charo, Romanowski, Gorgojo, Rodriguez, Carrera Silva and Gómez.

KEYWORDS: IFN-I; TAM receptors; human macrophages; junin virus; macrophage activation; macrophage polarization

PMID: 31695702 PMCID: PMC6817498 DOI: 10.3389/fimmu.2019.02499

Keywords: Arenavirus; Junin virus; Argentine Hemorrhagic Fever; Mopeia virus; Lassa fever virus; Viral pathogenesis.

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#Junín Virus Promotes #Autophagy to Facilitate Viral Life Cycle (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Junín Virus Promotes Autophagy to Facilitate Viral Life Cycle

Julieta S. Roldán, Nélida A. Candurra, María I. Colombo, Laura R. Delgui

DOI: 10.1128/JVI.02307-18

 

ABSTRACT

Junín virus (JUNV), a member of Arenaviridae family, is the etiological agent of Argentine hemorrhagic fever (AHF), a potentially deadly, endemic-epidemic disease affecting the population of the most fertile farming land of Argentina. Autophagy is a degradative process with a crucial anti-viral role; however, several viruses subvert this pathway in their benefit. We determined the role of autophagy in JUNV-infected cells analyzing LC3, a cytoplasmic protein (LC3-I) which becomes vesicle membrane-associated (LC3-II) upon induction of autophagy. Cells overexpressing EGFP-LC3 and infected with JUNV showed an increased number of LC3 puncta structures, similar to that obtained after starvation- or Bafilomycin A1- treatment which leads to autophagosome induction or accumulation, respectively. We also monitored the conversion of LC3-I to LC3-II observing LC3-II levels in JUNV-infected cells similar to that observed in starved cells. Additionally, we kinetically studied the number of LC3 dots after JUNV infection and found that the virus activated the pathway as early as 2 h p.i. whereas the UV-inactivated virus did not induce the pathway. Cells subjected to starvation or pre-treated with rapamycin, a pharmacological autophagy inductor, enhanced virus yield. Also, we assayed the replication capacity of JUNV in Atg 5 knock-out or Beclin-1 knock-down cells [both critical components of the autophagic pathway] and found a significant decrease in JUNV replication. Taken together, our results constitute the first study indicating that JUNV infection induces an autophagic response which is functionally required by the virus for efficient propagation.

 

IMPORTANCE

Mammalian arenaviruses are zoonotic viruses causing asymptomatic and persistent infections in their rodent hosts, but may produce severe and lethal haemorrhagic fevers in humans. Currently, there are neither effective therapeutic options nor effective vaccines, for viral haemorrhagic fevers caused by human pathogenic arenaviruses, except the vaccine Candid #1 against AHF, licensed for human use in endemic areas from Argentina. Since arenaviruses remain a severe threat to global public health, more in-depth knowledge of their replication mechanisms would improve our ability to fight against these viruses. Autophagy is a lysosomal degradative pathway involved in maintaining the cellular homeostasis, representing powerful anti-infective machinery. We showed, for the first time for a member of the Arenaviridae family, a pro-viral role of autophagy in JUNV infection, providing new knowledge in the edge of host-virus interaction. Therefore, modulation of virus-induced autophagy could be used as a strategy to block arenaviruses infections.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Arenavirus; Junin virus; Argentina Hemorrhagic Fever; Viral pathogenesis.

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Differential #Antibody-Based Immune #Response Against Isolated GP1 #RBDs from #Lassa and #Junín Viruses (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Differential Antibody-Based Immune Response Against Isolated GP1 Receptor-Binding Domains from Lassa and Junín Viruses

Aliza Borenstein-Katz, Anastasiya Shulman, Hedva Hamawi, Orith Leitner, Ron Diskin

DOI: 10.1128/JVI.00090-19

 

ABSTRACT

There are two predominant subgroups in the Arenaviridae family of viruses, the Old-World and the New-World viruses that use distinct cellular receptors for entry. While New-World viruses typically elicit good neutralizing antibody responses, the Old-World viruses generally evade such responses. Antibody based immune responses are directed against the glycoprotein spike complexes that decorate the viruses. A thick coat of glycans reduces the accessibility of antibodies to the surface of spike complexes from Old-World viruses but other mechanisms may further hamper the development of efficient humoral responses. Specifically, it was suggested that the GP1 receptor-binding module of the Old-World Lassa virus might help evading humoral response. Here we investigate the immunogenicity of the GP1 domain from Lassa virus and compare it to GP1 domain from the New-World Junín virus. We found striking differences in the ability of antibodies that were developed against these immunogens to target the same GP1 receptor-binding domains in the context of the native spike complexes. Whereas GP1 from Junín virus elicited productive neutralizing responses, GP1 from Lassa virus elicited only non-productive responses. These differences can be rationalized by conformational changes that GP1 from Lassa virus but not from Junín virus, undergoes after dissociating from the trimeric spike complex. Hence shedding of GP1 in the case of Lassa virus can indeed serve as a mechanism to subvert the humoral immune response. Moreover, the realization of using a recombinant protein for eliciting productive response against the New-World Junín virus may suggests a novel and safe way to design future vaccines.

 

IMPORTANCE

Some viruses that belong to the Arenaviridae family like Lassa and Junín viruses are notorious human pathogens, which may lead to fatal outcomes when they infect people. It is thus important to develop means to combat these viruses. For developing effective vaccines, it is vital to understand the basic mechanisms that these viruses utilize in order to evade or overcome host immune responses. It was previously noted that the GP1 receptor-binding domain from Lassa virus is shedded and accumulates in the sera of infected individuals. This raised the possibility that Lassa GP1 may function as an immunological decoy. Here we demonstrate that mice develop non-productive immune responses against GP1 from Lassa virus, which is in contrast to effective neutralizing responses that GP1 from Junín virus elicits. Thus, GP1 from Lassa virus is indeed an immunological decoy and GP1 from Junín virus may serve as a constituent of a future vaccine.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Arenavirus; Lassa fever; Junin virus; Animal models.

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Assessing cross-reactivity of #Junín virus-directed neutralizing #antibodies (Antiviral Res., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Antiviral Res. 2019 Jan 19. pii: S0166-3542(18)30591-6. doi: 10.1016/j.antiviral.2019.01.006. [Epub ahead of print]

Assessing cross-reactivity of Junín virus-directed neutralizing antibodies.

Leske A1, Waßmann I2, Schnepel K3, Shifflett K4, Holzerland J5, Bostedt L6, Bohn P7, Mettenleiter TC8, Briggiler AM9, Brignone J10, Enria D11, Cordo SM12, Hoenen T13, Groseth A14.

Author information: 1 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany. Electronic address: anne.leske@fli.de. 2 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany. Electronic address: iw142102@uni-greifswald.de. 3 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany. Electronic address: kevin.schnepel@uni-rostock.de. 4 Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA. Electronic address: kyle.shifflett@umconnect.umt.edu. 5 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany. Electronic address: julia.holzerland@fli.de. 6 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany. Electronic address: linus.bostedt@fli.de. 7 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany. Electronic address: pb132684@uni-greifswald.de. 8 Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany. Electronic address: thomasc.mettenleiter@fli.de. 9 Instituto Nacional de Enfermedades Virales Humanas, ANLIS, Pergamino, Argentina. Electronic address: abriggiler@hotmail.com. 10 Instituto Nacional de Enfermedades Virales Humanas, ANLIS, Pergamino, Argentina. Electronic address: jbrignone@anlis.gov.ar. 11 Instituto Nacional de Enfermedades Virales Humanas, ANLIS, Pergamino, Argentina. Electronic address: deliaenria@gmail.com. 12 Laboratory of Virology, IQUIBICEN-Department of Biochemistry, University of Buenos Aires, Buenos Aires, Argentina. Electronic address: scordo@qb.fcen.uba.ar. 13 Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA; Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany. Electronic address: thomas.hoenen@fli.de. 14 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany; Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA. Electronic address: allison.groseth@fli.de.

 

Abstract

Arenaviruses cause several viral hemorrhagic fevers endemic to Africa and South America. The respective causative agents are classified as biosafety level (BSL) 4 pathogens. Unlike for most other BSL4 agents, for the New World arenavirus Junín virus (JUNV) both a highly effective vaccination (Candid#1) and a post-exposure treatment, based on convalescent plasma transfer, are available. In particular, neutralizing antibodies (nAbs) represent a key protective determinant in JUNV infection, which is supported by the correlation between successful passive antibody therapy and the levels of nAbs administered. Unfortunately, comparable resources for the management of other closely related arenavirus infections are not available. Given the significant challenges inherent in studying BSL4 pathogens, our goal was to first assess the suitability of a JUNV transcription and replication-competent virus-like particle (trVLP) system for measuring virus neutralization under BSL1/2 conditions. Indeed, we could show that infection with JUNV trVLPs is glycoprotein (GP) dependent, that trVLP input has a direct correlation to reporter readout, and that these trVLPs can be neutralized by human serum with kinetics similar to those obtained using authentic virus. These properties make trVLPs suitable for use as a proxy for virus in neutralization assays. Using this platform we then evaluated the potential of JUNV nAbs to cross-neutralize entry mediated by GPs from other arenaviruses using JUNV (strain Romero)-based trVLPs bearing GPs either from other JUNV strains, other closely related New World arenaviruses (e.g. Tacaribe, Machupo, Sabiá), or the distantly related Lassa virus. While nAbs against the JUNV vaccine strain are also active against a range of other JUNV strains, they appear to have little or no capacity to neutralize other arenavirus species, suggesting that therapy with whole plasma directed against another species is unlikely to be successful and that the targeted development of cross-specific monoclonal antibody-based resources is likely needed. Such efforts will be supported by the availability of this BSL1/2 screening platform which provides a rapid and easy means to characterize the potency and reactivity of anti-arenavirus neutralizing antibodies against a range of arenavirus species.

Copyright © 2019. Published by Elsevier B.V.

KEYWORDS: Antibody cross-reactivity; Arenavirus; JunÍn virus; Neutralization assay; Neutralizing antibodies; Transcription and replication competent virus-like particle (trVLP) assay

PMID: 30668977 DOI: 10.1016/j.antiviral.2019.01.006

Keywords: Arenavirus; Junin virus; Machupo virus; Sabia virus; Tacaribe virus.

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A #proteomic survey of #Junín virus interactions with #human #proteins reveals host factors required for #arenavirus replication (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

A proteomic survey of Junín virus interactions with human proteins reveals host factors required for arenavirus replication

Christopher M. Ziegler1,2, Philip Eisenhauer1, Jamie A. Kelly1, Loan N. Dang1, Vedran Beganovic1, Emily A. Bruce1, Benjamin R. King1,2, David J. Shirley3, Marion E. Weir4, Bryan A. Ballif4 and Jason Botten1,3*

Author Affiliations: 1 Department of Medicine, Division of Immunobiology; 2Cellular, Molecular, and Biomedical Sciences Graduate Program; 3Department of Microbiology and Molecular Genetics; 4Department of Biology, University of Vermont, Burlington, VT 05405, USA

 

ABSTRACT

Arenaviruses are negative-strand, enveloped RNA viruses that cause significant human disease. In particular, Junín mammarenvirus (JUNV) is the etiologic agent of Argentine hemorrhagic fever. At present, little is known about the cellular proteins that the arenavirus matrix protein (Z) hijacks to accomplish its various functions, including driving the process of virus release. Further, there is a little knowledge regarding host proteins incorporated into arenavirus particles and their importance for virion function. To address these deficiencies, we used mass spectrometry to identify human proteins that (i) interact with the JUNV matrix protein inside of cells or within virus-like particles (VLPs) and/or (ii) are incorporated into bona fide JUNV strain Candid #1 particles. Bioinformatic analyses revealed that multiple classes of human proteins were overrepresented in the datasets, including ribosomal proteins, Ras superfamily proteins, and endosomal sorting complex required for transport (ESCRT) proteins. Several of these proteins were required for the propagation of JUNV (ARF1, ATP6V0D1 and PRDX3), lymphocytic choriomeningitis mammarenavirus (LCMV) (Rab5c), or both viruses (ATP5B, IMPDH2). Further, we show that release of infectious JUNV particles, but not LCMV particles, requires a functional ESCRT pathway and that ATP5B and IMPDH2 are required for JUNV budding. In summary, we have provided a large-scale map of host machinery that associates with JUNV and identified key human proteins required for its propagation. This dataset provides a resource for the field to guide antiviral target discovery and to better understand the biology of the arenavirus matrix protein and the importance of host proteins for virion function.

 

IMPORTANCE

Arenaviruses are deadly human pathogens for which there are no United States Food and Drug Administration-approved vaccines and only limited treatment options. Little is known about the host proteins that are incorporated into arenavirus particles or that associate with its multifunctional matrix protein. Using Junín mammarenavirus (JUNV), the causative agent of Argentine hemorrhagic fever, as a model organism, we mapped the human proteins that are incorporated into JUNV particles or that associate with the JUNV matrix protein. Functional analysis revealed host machinery that is required for JUNV propagation, including the cellular ESCRT pathway. This study improves our understanding of critical arenavirus-host interactions and provides a dataset that will guide future studies to better understand arenavirus pathogenesis and identify novel host proteins that can be therapeutically targeted.

 

FOOTNOTES

*Corresponding author: E-mail: jbotten@uvm.edu (JB), Telephone: 802-656-9795 (JB)

Copyright © 2017 American Society for Microbiology. All Rights Reserved.

Keywords: Arenavirus; Argentine Hemorrhagic Fever; Junin Mammarenavirus.

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#Merimepodib, an IMPDH #inhibitor, suppresses #replication of #Zika virus and other emerging viral #pathogens (Antiviral Res., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Antiviral Res. 2017 Nov 7. pii: S0166-3542(17)30237-1. doi: 10.1016/j.antiviral.2017.11.004. [Epub ahead of print]

Merimepodib, an IMPDH inhibitor, suppresses replication of Zika virus and other emerging viral pathogens.

Tong X1, Smith J2, Bukreyeva N2, Koma T2, Manning TJ2, Kalkeri R3, Kwong AD4, Paessler S5.

Author information: 1 Trek Therapeutics, PBC, 125 Cambridge Park Drive, Suite 301, Cambridge, MA 02140, UK. Electronic address: xiao.tong@trektx.com. 2 Department of Pathology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA. 3 Southern Research, 431 Aviation Way, Frederick, MD 21701, USA. 4 Trek Therapeutics, PBC, 125 Cambridge Park Drive, Suite 301, Cambridge, MA 02140, UK. 5 Department of Pathology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA. Electronic address: slpaessl@utmb.edu.

 

Abstract

Zika virus (ZIKV), a member of the Flaviviridae family, has recently been linked to abnormal pregnancies, fetal death, microcephaly, and Guillain-Barré syndrome in humans. Merimepodib (MMPD, VX-497), a potent inhibitor of inosine-5′-monophosphate dehydrogenase (IMPDH), has shown antiviral activity against HCV and a variety of DNA and RNA viruses in vitro. In this report, we expand the antiviral spectrum of MMPD, and demonstrate that MMPD inhibits ZIKV RNA replication with an EC50 of 0.6 μM. In a virus production assay, MMPD reduces the virus titer of ZIKV as well as several other important emerging viral pathogens such as Ebola, Lassa, Chikungunya, and Junin viruses. The inhibition can be reversed by addition of exogenous guanosine to culture media, consistent with the mechanism of action of MMPD as an IMPDH inhibitor. We also provide evidence that MMPD can be used in combination with other antivirals such as ribavirin and T-705 (favipiravir) to enhance suppression of virus production.

Copyright © 2017. Published by Elsevier B.V.

KEYWORDS: Antiviral; Ebola; IMPDH; Merimepodib; VX-497; Zika

PMID: 29126899 DOI: 10.1016/j.antiviral.2017.11.004

Keywords: Antivirals; Chikungunya Fever; Zika Virus; Ebola; Lassa; Junin Virus.

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Epistastic interactions within the #Junín virus envelope glycoprotein complex provide an #evolutionary barrier to reversion in the live-attenuated Candid#1 vaccine (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Epistastic interactions within the Junín virus envelope glycoprotein complex provide an evolutionary barrier to reversion in the live-attenuated Candid#1 vaccine

Joanne York and  Jack H Nunberg#

Author Affiliations: Montana Biotechnology Center, University of Montana, Missoula, Montana, United States of America

 

ABSTRACT

The Candid#1 strain of Junín virus was developed using a conventional attenuation strategy of serial passage in non-host animals and cultured cells. The live-attenuated Candid#1 vaccine is used in Argentina to protect at-risk individuals against Argentine hemorrhagic fever, but has not been licensed in the United States. Recent studies have revealed that Candid#1 attenuation is entirely dependent on a phenylalanine-to-isoleucine substitution at position 427 in the fusion subunit (GP2) of the viral envelope glycoprotein complex (GPC), thereby raising concerns regarding the potential for reversion to virulence. In this study, we report the identification and characterization of an intragenic epistatic interaction between the attenuating F427I mutation in GP2 and a lysine-to-serine mutation at position 33 in the stable signal peptide (SSP) subunit of GPC, and demonstrate the utility of this interaction in creating an evolutionary barrier against reversion to the pathogenic genotype. In the presence of the wild-type F427 residue, the K33S mutation abrogates the ability of ectopically expressed GPC to mediate membrane fusion at endosomal pH. This defect is rescued by the attenuating F427I mutation. We show that the recombinant Candid#1 (rCan) virus bearing K33S GPC is viable and retains its attenuated genotype under cell-culture conditions that readily select for reversion in the parental rCan virus. If back-mutation to F427 offers an accessible pathway to increase fitness in rCan, reversion in K33S-GPC rCan is likely to be lethal. The epistatic interaction between K33S and F427I may thus minimize the likelihood of reversion and enhance safety in a second-generation Candid#1 vaccine.

 

IMPORTANCE

The live-attenuated Candid#1 vaccine strain of Junín virus is used to protect against Argentine hemorrhagic fever. Recent findings that a single missense mutation in the viral envelope glycoprotein complex (GPC) is responsible for attenuation raise the prospect of facile reversion to pathogenicity. Here we characterize a genetic interaction between GPC subunits that evolutionarily forces retention of the attenuating mutation. By incorporating this secondary mutation into Candid#1 GPC, we hope to minimize the likelihood of reversion and enhance safety in a second-generation Candid#1 vaccine. A similar approach may guide the design of live-attenuated vaccines against Lassa and other arenaviral hemorrhagic fevers.

 

FOOTNOTES

#corresponding author: E-mail: jack.nunberg@umontana.edu (JHN)

Copyright © 2017 American Society for Microbiology. All Rights Reserved.

Keywords: Arenavirus; Junin Virus; Vaccines; Argentine Hemorrhagic Fever Virus.

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