scholarly journals Exacerbated Apoptosis of Cells Infected with Infectious Bursal Disease Virus upon Exposure to Interferon Alpha

2018 ◽  
Vol 92 (11) ◽  
Author(s):  
Liliana L. Cubas-Gaona ◽  
Elisabet Diaz-Beneitez ◽  
Marina Ciscar ◽  
José F. Rodríguez ◽  
Dolores Rodríguez
Keyword(s):  
Immune Response ◽  
Infectious Bursal Disease Virus ◽  
Infectious Bursal Disease ◽  
Type I ◽  
B Cell Depletion ◽  
Content Type ◽  
Tnf Α ◽  
Bursal Disease ◽  
Infected Cells ◽  
Main Factors

ABSTRACTInfectious bursal disease virus (IBDV) belongs to theBirnaviridaefamily and is the etiological agent of a highly contagious and immunosuppressive disease (IBD) that affects domestic chickens (Gallus gallus). IBD or Gumboro disease leads to high rates of morbidity and mortality of infected animals and is responsible for major economic losses to the poultry industry worldwide. IBD is characterized by a massive loss of IgM-bearing B lymphocytes and the destruction of the bursa of Fabricius. The molecular bases of IBDV pathogenicity are still poorly understood; nonetheless, an exacerbated cytokine immune response and B cell depletion due to apoptosis are considered main factors that contribute to the severity of the disease. Here we have studied the role of type I interferon (IFN) in IBDV infection. While IFN pretreatment confers protection against subsequent IBDV infection, the addition of IFN to infected cell cultures early after infection drives massive apoptotic cell death. Downregulation of double-stranded RNA (dsRNA)-dependent protein kinase (PKR), tumor necrosis factor alpha (TNF-α), or nuclear factor κB (NF-κB) expression drastically reduces the extent of apoptosis, indicating that they are critical proteins in the apoptotic response induced by IBDV upon treatment with IFN-α. Our results indicate that IBDV genomic dsRNA is a major viral factor that contributes to the triggering of apoptosis. These findings provide novel insights into the potential mechanisms of IBDV-induced immunosuppression and pathogenesis in chickens.IMPORTANCEIBDV infection represents an important threat to the poultry industry worldwide. IBDV-infected chickens develop severe immunosuppression, which renders them highly susceptible to secondary infections and unresponsive to vaccination against other pathogens. The early dysregulation of the innate immune response led by IBDV infection and the exacerbated apoptosis of B cells have been proposed as the main factors that contribute to virus-induced immunopathogenesis. Our work contributes for the first time to elucidating a potential mechanism driving the apoptotic death of IBDV-infected cells upon exposure to type I IFN. We provide solid evidence about the critical importance of PKR, TNF-α, and NF-κB in this phenomenon. The described mechanism could facilitate the early clearance of infected cells, thereby aiding in the amelioration of IBDV-induced pathogenesis, but it could also contribute to B cell depletion and immunosuppression. The balance between these two opposing effects might be dramatically affected by the genetic backgrounds of both the host and the infecting virus strain.

scholarly journals Type I Interferon acts as a major barrier to the establishment of infectious bursal disease virus (IBDV) persistent infections

2020 ◽  
pp. JVI.02017-20
Author(s):  
Laura Broto ◽  
Nicolás Romero ◽  
Fernando Méndez ◽  
Elisabet Diaz-Beneitez ◽  
Oscar Candelas-Rivera ◽  
...  
Keyword(s):  
Disease Virus ◽  
Cell Lines ◽  
Infectious Bursal Disease Virus ◽  
Infectious Bursal Disease ◽  
Type I ◽  
Persistently Infected ◽  
Persistent Infections ◽  
Avian Pathogen ◽  
Bursal Disease ◽  
Infected Cells

Infectious bursal disease virus (IBDV), the best characterized member of the Birnaviridae family, is a highly relevant avian pathogen causing both acute and persistent infections in different avian hosts. Here, we describe the establishment of clonal, long-term, productive persistent IBDV infections in DF-1 chicken embryonic fibroblasts. Although virus yields in persistently-infected cells are exceedingly lower than those detected in acutely infected cells, the replication fitness of viruses isolated from persistently-infected cells is higher than that of the parental virus. Persistently-infected DF-1 and IBDV-cured cell lines derived from them do not respond to type I interferon (IFN). High-throughput genome sequencing revealed that this defect is due to mutations affecting the IFNα/β receptor subunit 2 (IFNAR2) gene resulting in the expression of IFNAR2 polypeptides harbouring large C-terminal deletions that abolish the signalling capacity of IFNα/β receptor complex. Ectopic expression of a recombinant chicken IFNAR2 gene efficiently rescues IFNα responsiveness. IBDV-cured cell lines derived from persistently infected cells exhibit a drastically enhanced susceptibility to establishing new persistent IBDV infections. Additionally, experiments carried out with human HeLa cells lacking the IFNAR2 gene fully recapitulate results obtained with DF-1 cells, exhibiting a highly enhanced capacity to both survive the acute IBDV infection phase and to support the establishment of persistent IBDV infections. Results presented here show that the inactivation of the JAK-STAT signalling pathway significantly reduces the apoptotic response induced by the infection, hence facilitating the establishment and maintenance of IBDV persistent infections.IMPORTANCE Members of the Birnaviridae family, including infectious bursal disease virus (IBDV), exhibit a dual behaviour, causing acute infections that are often followed by the establishment of life-long persistent asymptomatic infections. Indeed, persistently infected specimens might act as efficient virus reservoirs, hence potentially contributing to virus dissemination. Despite the key importance of this biological trait, information about mechanisms triggering IBDV persistency is negligible. Our report evidences the capacity of IBDV, a highly relevant avian pathogen, to establishing long-term, productive, persistent infections in both avian and human cell lines. Data presented here provide novel and direct evidence about the crucial role of type I IFNs on the fate of IBDV-infected cells and their contribution to controlling the establishment of IBDV persistent infections. The use of cell lines unable to respond to type I IFNs opens a promising venue to unveiling additional factors contributing to IBDV persistency.

scholarly journals Type I Interferon acts as a major barrier to the establishment of infectious bursal disease virus (IBDV) persistent infections

2020 ◽  
Author(s):  
Laura Broto ◽  
Nicolás Romero ◽  
Fernando Méndez ◽  
Elisabet Diaz-Beneitez ◽  
Oscar Candelas-Rivera ◽  
...  
Keyword(s):  
Disease Virus ◽  
Cell Lines ◽  
Infectious Bursal Disease Virus ◽  
Infectious Bursal Disease ◽  
Type I ◽  
Persistently Infected ◽  
Persistent Infections ◽  
Avian Pathogen ◽  
Bursal Disease ◽  
Infected Cells

ABSTRACTInfectious bursal disease virus (IBDV), the best characterized member of the Birnaviridae family, is a highly relevant avian pathogen causing both acute and persistent infections in different avian hosts. Here, we describe the establishment of clonal, long-term, productive persistent IBDV infections in DF-1 chicken embryonic fibroblasts. Although virus yields in persistently-infected cells are exceedingly lower than those detected in acutely infected cells, the replication fitness of viruses isolated from persistently-infected cells is higher than that of the parental virus. Persistently-infected DF-1 and IBDV-cured cell lines derived from them do not respond to type I interferon (IFN). High-throughput genome sequencing revealed that this defect is due to mutations affecting the IFNα/β receptor subunit 2 (IFNAR2) gene resulting in the expression of IFNAR2 polypeptides harbouring large C-terminal deletions that abolish the signalling capacity of IFNα/β receptor complex. Ectopic expression of a recombinant chicken IFNAR2 gene efficiently rescues IFNα responsiveness. IBDV-cured cell lines derived from persistently infected cells exhibit a drastically enhanced proneness to establishing new persistent IBDV infections. Additionally, experiments carried out with human HeLa cells lacking the IFNAR2 gene fully recapitulate results obtained with DF-1 cells, exhibiting a highly enhanced capacity to both survive the acute IBDV infection phase and to support the establishment of persistent IBDV infections. Results presented here show that the inactivation of the JAK-STAT signalling pathway significantly reduces the apoptotic response induced by the infection, hence facilitating the establishment and maintenance of IBDV persistent infections.IMPORTANCEMembers of the Birnaviridae family, including infectious bursal disease virus (IBDV), exhibit a dual behaviour, causing acute infections that are often followed by the establishment of life-long persistent asymptomatic infections. Indeed, persistently infected specimens might act as efficient virus reservoirs, hence potentially contributing to virus dissemination. Despite the key importance of this biological trait, information about mechanisms triggering IBDV persistency is negligible. Our report evidences the capacity of IBDV, a highly relevant avian pathogen, to establishing long-term, productive, persistent infections in both avian and human cell lines. Data presented here provide novel and direct evidence about the crucial role of type I IFNs on the fate of IBDV-infected cells and their contribution to controlling the establishment of IBDV persistent infections. The use of cell lines unable to respond to type I IFNs opens a promising venue to unveiling additional factors contributing to IBDV persistency.

scholarly journals Infectious Bursal Disease Virus Hijacks Endosomal Membranes as the Scaffolding Structure for Viral Replication

2018 ◽  
Vol 92 (11) ◽  
Author(s):  
María Cecilia Gimenez ◽  
Flavia Adriana Zanetti ◽  
Mauricio R. Terebiznik ◽  
María Isabel Colombo ◽  
Laura Ruth Delgui
Keyword(s):  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Infectious Bursal Disease ◽  
Content Type ◽  
Bursal Disease ◽  
Endosomal Membranes ◽  
Relevant Role ◽  
Infected Cells ◽  
Dsrna Viruses

ABSTRACTBirnaviruses are unconventional members of the group of double-stranded RNA (dsRNA) viruses that are characterized by the lack of a transcriptionally active inner core. Instead, the birnaviral particles organize their genome in ribonucleoprotein complexes (RNPs) composed by dsRNA segments, the dsRNA-binding VP3 protein, and the virally encoded RNA-dependent RNA polymerase (RdRp). This and other structural features suggest that birnaviruses may follow a completely different replication program from that followed by members of theReoviridaefamily, supporting the hypothesis that birnaviruses are the evolutionary link between single-stranded positive RNA (+ssRNA) and dsRNA viruses. Here we demonstrate that infectious bursal disease virus (IBDV), a prototypical member of theBirnaviridaefamily, hijacks endosomal membranes of infected cells through the interaction of a viral protein, VP3, with the phospholipids on the cytosolic leaflet of these compartments for replication. Employing a mutagenesis approach, we demonstrated that VP3 domain PATCH 2 (P2) mediates the association of VP3 with the endosomal membranes. To determine the role of VP3 P2 in the context of the virus replication cycle, we used avian cells stably overexpressing VP3 P2 for IBDV infection. Importantly, the intra- and extracellular virus yields, as well as the intracellular levels of VP2 viral capsid protein, were significantly diminished in cells stably overexpressing VP3 P2. Together, our results indicate that the association of VP3 with endosomes has a relevant role in the IBDV replication cycle. This report provides direct experimental evidence for membranous compartments such as endosomes being required by a dsRNA virus for its replication. The results also support the previously proposed role of birnaviruses as an evolutionary link between +ssRNA and dsRNA viruses.IMPORTANCEInfectious bursal disease (IBD; also called Gumboro disease) is an acute, highly contagious immunosuppressive disease that affects young chickens and spreads worldwide. The etiological agent of IBD is infectious bursal disease virus (IBDV). This virus destroys the central immune organ (bursa of Fabricius), resulting in immunosuppression and reduced responses of chickens to vaccines, which increase their susceptibility to other pathogens. IBDV is a member ofBirnaviridaefamily, which comprises unconventional members of dsRNA viruses, whose replication strategy has been scarcely studied. In this report we show that IBDV hijacks the endosomes of the infected cells for establishing viral replication complexes via the association of the ribonucleoprotein complex component VP3 with the phospholipids in the cytosolic leaflet of endosomal membranes. We show that this interaction is mediated by the VP3 PATCH 2 domain and demonstrate its relevant role in the context of viral infection.

scholarly journals Nuclear Factor NF45 Interacts with Viral Proteins of Infectious Bursal Disease Virus and Inhibits Viral Replication

2010 ◽  
Vol 84 (20) ◽  
pp. 10592-10605 ◽  
Author(s):  
Ruth L. O. Stricker ◽  
Sven-Erik Behrens ◽  
Egbert Mundt
Keyword(s):  
Viral Replication ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Molecular Mechanisms ◽  
Viral Proteins ◽  
Infectious Bursal Disease ◽  
Nuclear Factor ◽  
Replication Process ◽  
Bursal Disease ◽  
Infected Cells

ABSTRACT Two of the central issues in developing new strategies to interfere with viral infections concern the identification of cellular proteins involved in viral replication and/or antiviral measures and the dissection of the underlying molecular mechanisms. To gain initial insight into the role of host proteins in the life cycle of infectious bursal disease virus (IBDV), a double-stranded RNA virus, we examined the cellular nuclear factor 45 (NF45). NF45 was previously indicated to be involved in the replication process of other types of RNA viruses. Interestingly, by performing immunofluorescence studies, we found that in IBDV-infected cells the mainly nuclear NF45 accumulated at the sites of viral replication in the cytoplasm. NF45 was shown to specifically colocalize with the viral RNA-dependent RNA polymerase VP1, the capsid protein VP2, and the ribonucleoprotein VP3. Immunoprecipitation experiments indicated protein-protein associations between NF45 and VP1, VP2, and VP3. Expression of the individual VP3 or the combination of expression of VP1 and VP3 did not result in a cytoplasmic accumulation of NF45, which, among other data, showed that recruitment of the cellular protein in infected cells functionally correlates with the viral replication process. Since small interfering RNA(siRNA)-mediated downregulation of NF45 resulted in an approximately 5-fold increase of virus yield, our study suggests that NF45, by association with viral proteins, is part of a yet-uncharacterized cellular defense mechanism against IBDV infections.

Interactions in vivo between the proteins of infectious bursal disease virus: capsid protein VP3 interacts with the RNA-dependent RNA polymerase, VP1

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 209-218 ◽  
Author(s):  
Mirriam G. J. Tacken ◽  
Peter J. M. Rottier ◽  
Arno L. J. Gielkens ◽  
Ben P. H. Peeters
Keyword(s):  
Disease Virus ◽  
Protein Interactions ◽  
Infectious Bursal Disease Virus ◽  
Viral Proteins ◽  
Infectious Bursal Disease ◽  
Transactivation Domain ◽  
Protein Protein Interactions ◽  
Bursal Disease ◽  
Infected Cells

Little is known about the intermolecular interactions between the viral proteins of infectious bursal disease virus (IBDV). By using the yeast two-hybrid system, which allows the detection of protein–protein interactions in vivo, all possible interactions were tested by fusing the viral proteins to the LexA DNA-binding domain and the B42 transactivation domain. A heterologous interaction between VP1 and VP3, and homologous interactions of pVP2, VP3, VP5 and possibly VP1, were found by co-expression of the fusion proteins in Saccharomyces cerevisiae. The presence of the VP1–VP3 complex in IBDV-infected cells was confirmed by co-immunoprecipitation studies. Kinetic analyses showed that the complex of VP1 and VP3 is formed in the cytoplasm and eventually is released into the cell-culture medium, indicating that VP1–VP3 complexes are present in mature virions. In IBDV-infected cells, VP1 was present in two forms of 90 and 95 kDa. Whereas VP3 initially interacted with both the 90 and 95 kDa proteins, later it interacted exclusively with the 95 kDa protein both in infected cells and in the culture supernatant. These results suggest that the VP1–VP3 complex is involved in replication and packaging of the IBDV genome.

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