Comparative biochemical and functional analysis of viral and human secreted tumor necrosis factor (TNF) decoy receptors

© 2015 by The American Society for Biochemistry and Molecular Biology, Inc. The blockade of tumor necrosis factor (TNF) by etanercept, a soluble version of the human TNF receptor 2 (hTNFR2), is a well established strategy to inhibit adverse TNF-mediated inflammatory responses in the clinic. A similar strategy is employed by poxviruses, encoding four viral TNF decoy receptor homologues (vTNFRs) named cytokine response modifier B (CrmB), CrmC, CrmD, and CrmE. These vTNFRs are differentially expressed by poxviral species, suggesting distinct immunomodulatory properties. Whereas the human variola virus and mouse ectromelia virus encode one vTNFR, the broad host range cowpox virus encodes all vTNFRs. We report the first comprehensive study of the functional and binding properties of these four vTNFRs, providing an explanation for their expression profile among different poxviruses. In addition, the vTNFRs activities were compared with the hTNFR2 used in the clinic. Interestingly, CrmB from variola virus, the causative agent of smallpox, is the most potent TNFR of those tested here including hTNFR2. Furthermore, we demonstrate a new immunomodulatory activity of vTNFRs, showing that CrmB and CrmD also inhibit the activity of lymphotoxin β. Similarly, we report for the first time that the hTNFR2 blocks the biological activity of lymphotoxin β. The characterization of vTNFRs optimized during virus-host evolution to modulate the host immune response provides relevant information about their potential role in pathogenesis and may be used to improve anti-inflammatory therapies based on soluble decoy TNFRs.Ministry of Economy and Competitiveness Grants SAF2009-07857 and SAF2012-38957Peer Reviewe

Poxvirus-encoded TNF decoy receptors inhibit the biological activity of transmembrane TNF

© 2015 The Authors. Poxviruses encode up to four different soluble TNF receptors, named cytokine response modifier B (CrmB), CrmC, CrmD and CrmE. These proteins mimic the extracellular domain of the cellular TNF receptors to bind and inhibit the activity of TNF and, in some cases, other TNF superfamily ligands. Most of these ligands are released after the enzymic cleavage of a membrane precursor. However, transmembrane TNF (tmTNF) is not only a precursor of soluble TNF but also exerts specific pro-inflammatory and immunological activities. Here, we report that viral TNF receptors bound and inhibited tmTNF and describe some interesting differences in their activity against the soluble cytokine. Thus, CrmE, which does not inhibit mouse soluble TNF, could block murine tmTNF-induced cytotoxicity. We propose that this anti-tmTNF effect should be taken into consideration when assessing the role of viral TNF decoy receptors in the pathogenesis of poxvirus.Ministry of Economy and Competitiveness Grants SAF2009-07857 and SAF2012-38957.S. M. P. was recipient of a JAE PhD Studentship from Consejo Superior de Investigaciones Científicas and a studentship from Fundación Severo OchoaPeer Reviewe

The genome sequence of the emerging common midwife toad virus identifies an evolutionary intermediate within ranaviruses

Worldwide amphibian population declines have been ascribed to global warming, increasing pollution levels, and other factors directly related to human activities. These factors may additionally be favoring the emergence of novel pathogens. In this report, we have determined the complete genome sequence of the emerging common midwife toad ranavirus (CMTV), which has caused fatal disease in several amphibian species across Europe. Phylogenetic and gene content analyses of the first complete genomic sequence from a ranavirus isolated in Europe show that CMTV is an amphibian-like ranavirus (ALRV). However, the CMTV genome structure is novel and represents an intermediate evolutionary stage between the two previously described ALRV groups. We find that CMTV clusters with several other ranaviruses isolated from different hosts and locations which might also be included in this novel ranavirus group. This work sheds light on the phylogenetic relationships within this complex group of emerging, disease-causing viruses. © 2012, American Society for Microbiology.Peer Reviewe

Complete genome sequence of the European sheatfish virus

Viral diseases are an increasing threat to the thriving aquaculture industry worldwide. An emerging group of fish pathogens is formed by several ranaviruses, which have been isolated at different locations from freshwater and seawater fish species since 1985.We report the complete genome sequence of European sheatfish ranavirus (ESV), the first ranavirus isolated in Europe, which causes high mortality rates in infected sheatfish (Silurus glanis) and in other species. Analysis of the genome sequence shows that ESV belongs to the amphibian- like ranaviruses and is closely related to the epizootic hematopoietic necrosis virus (EHNV), a disease agent geographically confined to the Australian continent and notifiable to the World Organization for Animal HealthThis work was supported by grant AGL 2009-08711 from the Spanish Ministerio de Ciencia e Innovación. Alberto López-Bueno and Carla Mavian are recipients of Ramón y Cajal and Formación de Personal Investigador fellowships, respectively, from the same institutio

Incidencia de los virus de la enfermedad de linfocistis (LCDV-Sa), papillomavirus (SaPV1) y poliomavirus (SaPyV1) en doradas cultivadas en el área mediterránea

La enfermedad de linfocistis (LCD), causada por el virus de la enfermedad de linfocistis (LCDV), es una patología común descrita en más de 150 especies de peces en todo el mundo, siendo la enfermedad de etiología viral más frecuentemente detectada en las piscifactorías de dorada (Sparus aurata) localizadas en el sur de Europa. En un estudio previo se secuenció directamente el viroma de lesiones de doradas enfermas, obteniéndose el genoma completo de una nueva especie de LCDV (a la que se ha denominado LCDV-Sa) junto a los genomas completos de dos nuevos virus pertenecientes a los papillomavirus y poliomavirus, denominados Sparus aurata papillomavirus 1 (SaPV1) y Sparus aurata polyomavirus 1 (SaPyV1), respectivamente. En el presente trabajo se han llevado a cabo análisis de PCR y nested-PCR para la detección específica de los 3 virus mencionados en muestras procedentes de 130 especímenes de dorada, tanto asintomáticos como afectados por la LCD, recogidas en diferentes piscifactorías localizadas en España, Italia y Turquía durante los años 2009-2015. Los resultados obtenidos muestran que en los peces enfermos la detección de LCDV-Sa viene casi invariablemente acompañada por la detección de al menos uno de los nuevos virus (98% de las muestras analizadas). Sin embargo, solo un 24% de los peces asintomáticos positivos para LCDV-Sa (74,6% de los animales asintomáticos analizados) resultaron positivos para SaPV1 y/o SaPyV1. Estos resultados confirman la asociación de los tres virus durante el desarrollo de la enfermedad de linfocistis en dorada, si bien se requerirán estudios posteriores para establecer el papel de cada uno de ellos en la patogénesis de dicha enfermedad.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The genome sequence of the emerging common midwife toad virus identifies an evolutionary intermediate within ranaviruses

Worldwide amphibian population declines have been ascribed to global warming, increasing pollution levels, and other factors directly related to human activities. These factors may additionally be favoring the emergence of novel pathogens. In this report, we have determined the complete genome sequence of the emerging common midwife toad ranavirus (CMTV), which has caused fatal disease in several amphibian species across Europe. Phylogenetic and gene content analyses of the first complete genomic sequence from a ranavirus isolated in Europe show that CMTV is an amphibian-like ranavirus (ALRV). However, the CMTV genome structure is novel and represents an intermediate evolutionary stage between the two previously described ALRV groups. We find that CMTV clusters with several other ranaviruses isolated from different hosts and locations which might also be included in this novel ranavirus group. This work sheds light on the phylogenetic relationships within this complex group of emerging, disease-causing viruses.This work was supported by grant AGL 2009-08711 from the Spanish Ministerio de Ciencia e Innovación. Alberto López-Bueno and Carla Mavián are recipients of the Ramón y Cajal and Formación del Personal Investigador fellowships, respectively, from the same institutio

Novel polyomavirus and papillomavirus detected in gilthead seabream infected by lymphocystis disease virus

Lymphocystis disease virus (LCDV), a member of the genus Lymphocystivirus, family Iridoviridae, is the etiological agent of the lymphocystis disease (LCD), a common pathology that has been described in more than 150 different fish species worldwide. Direct sequencing of the virome of lymphocystis lesions from affected gilthead seabream (Sparus aurata) was used to obtain the complete genome sequence of a new LCDV species, named LCDV-Sa, that is the largest vertebrate iridovirus sequenced to date. This approach allowed us to assemble the full-length circular genomes of two previously unknown viruses, tentatively identified as members of the Polyomaviridae and Papillomaviridae families, and named Sparus aurata polyomavirus 1 (SaPyV1) and Sparus aurata papillomavirus 1 (SaPV1), respectively. SaPyV1 genome is a circular 7,299-bp-long DNA with a 52.1% GC content, and contains five nonoverlapping ORFs carried on opposite DNA strands in an organization reminiscent to that found in polyomaviruses. Phylogenetic analyses based on the amino acid sequence of the large T antigen and the VP1 proteins revealed that SaPyV1 clustered with the other currently available polyomavirus-like full-length genomes obtained from fish. SaPV1 genome corresponds to a circular 5,748-bp-long DNA and has a GC content of 39.5%. Although this genome is smaller than that of previously described papillomaviruses (about 8 kbp), it presents a typical papillomavirus organization, with seven ORFs carried on the same strand. Similarity searches identified distant orthologues of the early E1 and E2 proteins involved in replication and transcription, and late structural proteins L1 and L2. Furthermore, one of the others ORFs encodes a small protein (52 amino acids) that contains both a pRB binding domain (LXCXE) and a C-terminal PDZ class 2 binding motif, with are elements typically present in the longer E7 and E6 proteins found in most known papillomaviruses. The conserved genomic organization, the similarity of the main proteins, and the phylogenetical analysis, based on the amino acid sequence of the L1 protein, support that SaPV1 is the first member of the Papillomaviridae family described in fish. Epizootic surveys carried out in gilthead seabream farms in the Mediterranean area showed that LCD is frequently associated with the concurrent appearance of one or both of the new viruses, 98.3% of diseased fish being positive for SaPyV1 and/or SaPV1. In LCDV-infected asymptomatic fish, SaPyV1 and/or SaPV1 were detected in 32.1% of the animals analysed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The highly virulent variola and monkeypox viruses express secreted inhibitors of type I interferon

Variola virus (VARV) caused smallpox, one of the most devastating human diseases and the first to be eradicated, but its deliberate release represents a dangerous threat. Virulent orthopoxviruses infecting humans, such as monkeypox virus (MPXV), could fill the niche left by smallpox eradication and the cessation of vaccination. However, immunomodulatory activities and virulence determinants of VARV and MPXV remain largely unexplored. We report the molecular characterization of the VARV- and MPXV-secreted type I interferon-binding proteins, which interact with the cell surface after secretion and prevent type I interferon responses. The proteins expressed in the baculovirus system have been purified, and their interferon-binding properties characterized by surface plasmon resonance. The ability of these proteins to inhibit a broad range of interferons was investigated to identify potential adaptation to the human immune system. Furthermore, we demonstrate by Western blot and activity assays the expression of the type I interferon inhibitor during VARV and MPXV infections. These findings are relevant for the design of new vaccines and therapeutics to smallpox and emergent virulent orthopoxviruses because the type I interferon- binding protein is a major virulence factor in animal models, vaccination with this protein induces protective immunity, and its neutralization prevents disease progression

Estudio de la geranilgeranilpirofosfato sintasa codificada por el virus de la peste porcina africana

Tesis doctoral inédita leída el 08 de octubre de 1999 en la Universidad Autónoma de Madrid.Peer reviewe

Poxviral TNFRs: Properties and Role in Viral Pathogenesis

Tumor necrosis factor (TNF) is the prototypical member of a large superfamily of structurally related cytokines that are involved in a wide range of activities involved in the regulation of the immune response and developmental processes and that signal mainly through an equally diverse array of receptors included in the TNF receptor superfamily (TNFRSF). TNF has an essential role in the activation of the antiviral immune response, where it acts both directly on virus-infected cells as a cell death-inducing cytokine and indirectly in the activation of the innate and adaptive immune responses against the invading pathogen. Consequently, viruses from different families have devised strategies to evade or modulate these TNF-driven responses. Most strategies involve the expression of virus-encoded intracellular proteins that are able to bind to different proteins of the TNFR signal transduction pathways. Uniquely, poxviruses express secreted TNFR homologues that can bind to soluble TNF, inhibiting its activity by preventing it from binding to the cellular receptors. In the recent years, we have been interested in studying the activity and function of these viral TNFRs (vTNFRs) both in vitro and during infection. We describe recent advances in this field.Peer reviewe