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Divergent Evolutionary Pathways of Myxoma Virus in Australia: Virulence Phenotypes in Susceptible and Partially Resistant Rabbits Indicate Possible Selection for Transmissibility. J Virol 2022; 96:e0088622. [PMID: 36197107 PMCID: PMC9599488 DOI: 10.1128/jvi.00886-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To characterize the ongoing evolution of myxoma virus in Australian rabbits, we used experimental infections of laboratory rabbits to determine the virulence and disease phenotypes of recent virus isolates. The viruses, collected between 2012 and 2015, fell into three lineages, one of which, lineage c, experienced a punctuated increase in evolutionary rate. All viruses were capable of causing acute death with aspects of neutropenic septicemia, characterized by minimal signs of myxomatosis, the occurrence of pulmonary edema and bacteria invasions throughout internal organs, but with no inflammatory response. For the viruses of highest virulence all rabbits usually died at this point. In more attenuated viruses, some rabbits died acutely, while others developed an amyxomatous phenotype. Rabbits that survived for longer periods developed greatly swollen cutaneous tissues with very high virus titers. This was particularly true of lineage c viruses. Unexpectedly, we identified a line of laboratory rabbits with some innate resistance to myxomatosis and used these in direct comparisons with the fully susceptible rabbit line. Importantly, the same disease phenotype occurred in both susceptible and resistant rabbits, although virulence was shifted toward more attenuated grades in resistant animals. We propose that selection against inflammation at cutaneous sites prolongs virus replication and enhances transmission, leading to the amyxomatous phenotype. In some virus backgrounds this creates an immunosuppressive state that predisposes to high virulence and acute death. The alterations in disease pathogenesis, particularly the overwhelming bacterial invasions that characterize the modern viruses, suggest that their virulence grades are not directly comparable with earlier studies. IMPORTANCE The evolution of the myxoma virus (MYXV) following its release as a biological control for European rabbits in Australia is the textbook example of the coevolution of virus virulence and host resistance. However, most of our knowledge of MYXV evolution only covers the first few decades of its spread in Australia and often with little direct connection between how changes in virus phenotype relate to those in the underlying virus genotype. By conducting detailed experimental infections of recent isolates of MYXV in different lines of laboratory rabbits, we examined the ongoing evolution of MYXV disease phenotypes. Our results reveal a wide range of phenotypes, including an amyxomatous type, as well as the impact of invasive bacteria, that in part depended on the level of rabbit host resistance. These results provide a unique insight into the complex virus and host factors that combine to shape disease phenotype and viral evolution.
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Sheppard EC, Martin CA, Armstrong C, González-Quevedo C, Illera JC, Suh A, Spurgin LG, Richardson DS. Genomic associations with poxvirus across divergent island populations in Berthelot's pipit. Mol Ecol 2022; 31:3154-3173. [PMID: 35395699 PMCID: PMC9321574 DOI: 10.1111/mec.16461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/04/2022] [Accepted: 04/04/2022] [Indexed: 11/30/2022]
Abstract
Understanding the mechanisms and genes that enable animal populations to adapt to pathogens is important from an evolutionary, health and conservation perspective. Berthelot's pipit (Anthus berthelotii) experiences extensive and consistent spatial heterogeneity in avian pox infection pressure across its range of island populations, thus providing an excellent system with which to examine how pathogen-mediated selection drives spatial variation in immunogenetic diversity. Here we test for evidence of genetic variation associated with avian pox at both an individual and population-level. At the individual level, we find no evidence that variation in MHC class I and TLR4 (both known to be important in recognising viral infection) was associated with pox infection within two separate populations. However, using genotype-environment association (Bayenv) in conjunction with genome-wide (ddRAD-seq) data, we detected strong associations between population-level avian pox prevalence and allele frequencies of single nucleotide polymorphisms (SNPs) at a number of sites across the genome. These sites were located within genes involved in cellular stress signalling and immune responses, many of which have previously been associated with responses to viral infection in humans and other animals. Consequently, our analyses indicates that pathogen-mediated selection may play a role in shaping genomic variation among relatively recently colonised island bird populations and highlights the utility of genotype-environment associations for identifying candidate genes potentially involved in host-pathogen interactions.
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Affiliation(s)
- Eleanor C Sheppard
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK
| | - Claudia A Martin
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK
| | - Claire Armstrong
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK
| | - Catalina González-Quevedo
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK.,Grupo Ecología y Evolución de Vertebrados, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
| | - Juan Carlos Illera
- Biodiversity Research Institute (CSIC-Oviedo University-Principality of Asturias), University of Oviedo, Campus of Mieres, Research Building, 5th Floor, c/ Gonzalo Gutiérrez Quirós, s/n, 33600 Mieres, Asturias, Spain
| | - Alexander Suh
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK.,Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre (EBC), Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Lewis G Spurgin
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK
| | - David S Richardson
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norfolk, NR4 7TJ, UK
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MARCH8 Restricts Influenza A Virus Infectivity but Does Not Downregulate Viral Glycoprotein Expression at the Surface of Infected Cells. mBio 2021; 12:e0148421. [PMID: 34517760 PMCID: PMC8546552 DOI: 10.1128/mbio.01484-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Membrane-associated RING-CH8 (MARCH8) impairs the cell surface expression of envelope glycoproteins from different viruses, reducing their incorporation into virions. Using stable cell lines with inducible MARCH8 expression, we show that MARCH8 did not alter susceptibility to influenza A virus (IAV) infection, but virions released from infected cells were markedly less infectious. Knockdown of endogenous MARCH8 confirmed its effect on IAV infectivity. The expression of MARCH8 impaired the infectivity of both H3N2 and H1N1 strains and was dependent on its E3 ligase activity. Although virions released in the presence of MARCH8 expressed smaller amounts of viral hemagglutinin (HA) and neuraminidase (NA) proteins, there was no impact on levels of the viral HA, NA, or matrix 2 (M2) proteins detected on the surface of infected cells. Moreover, mutation of lysine residues in the cytoplasmic tails of HA, NA, and/or M2, or in the viral M1 protein, did not abrogate MARCH8-mediated restriction. While MARCH1 and -8 target similar immunological ligands and both restrict HIV-1, only MARCH8 inhibited IAV infectivity. Deletion of the N-terminal cytoplasmic (N-CT) domain of MARCH8 confirmed it to be a critical determinant of IAV inhibition. Of interest, deletion of the MARCH1 N-CT or its replacement with the MARCH8 N-CT resulted in acquisition of IAV restriction. Together, these data demonstrate that MARCH8 restricts a late stage in IAV replication by a mechanism distinct to its reported activity against other viruses. Moreover, we show that the N-CT of MARCH8 is essential for anti-IAV activity, whereas the MARCH1 N-CT inhibits its ability to restrict IAV.
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Lant S, Maluquer de Motes C. Poxvirus Interactions with the Host Ubiquitin System. Pathogens 2021; 10:pathogens10081034. [PMID: 34451498 PMCID: PMC8399815 DOI: 10.3390/pathogens10081034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 12/16/2022] Open
Abstract
The ubiquitin system has emerged as a master regulator of many, if not all, cellular functions. With its large repertoire of conjugating and ligating enzymes, the ubiquitin system holds a unique mechanism to provide selectivity and specificity in manipulating protein function. As intracellular parasites viruses have evolved to modulate the cellular environment to facilitate replication and subvert antiviral responses. Poxviruses are a large family of dsDNA viruses with large coding capacity that is used to synthetise proteins and enzymes needed for replication and morphogenesis as well as suppression of host responses. This review summarises our current knowledge on how poxvirus functions rely on the cellular ubiquitin system, and how poxviruses exploit this system to their own advantage, either facilitating uncoating and genome release and replication or rewiring ubiquitin ligases to downregulate critical antiviral factors. Whilst much remains to be known about the intricate interactions established between poxviruses and the host ubiquitin system, our knowledge has revealed crucial viral processes and important restriction factors that open novel avenues for antiviral treatment and provide fundamental insights on the biology of poxviruses and other virus families.
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Label-free rapid electrochemical detection of DNA hybridization using ultrasensitive standalone CNT aerogel biosensor. Biosens Bioelectron 2021; 191:113480. [PMID: 34242998 DOI: 10.1016/j.bios.2021.113480] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/10/2021] [Accepted: 07/02/2021] [Indexed: 01/14/2023]
Abstract
We report the development of an ultrasensitive label-free DNA biosensor device with fully integrated standalone carbon nanotube (CNT) aerogel electrode. The multi-directional tenuous network of clustered CNT embedding into the CNT aerogel electrode demonstrates linear ohmic and near isotropic electrical properties, thereby providing high sensitivity for nucleic acid detection. Using this device, the target DNA hybridization is detected by a quantifiable change in the electrochemical impedance, with a distinct response to the single-stranded probe alone or double-stranded target-probe complex. The target DNA is specifically detected with limit of detection (LoD) of 1 pM with a turnaround time of less than 20 min, which is unprecedented for a miniaturized CNT aerogel sensor and impedance spectroscopy without an intermediate DNA amplification step. Moreover, this system is able to differentiate between the closely related target sequences by the distinct impedance response rendering it highly specific. To the best of our knowledge, this is the first report showing the use of standalone bare CNT aerogel electrode without any substrate support, coupled with electrochemical impedance spectroscopy, for the detection of DNA hybridization. Altogether, the results show that our system is fast, sensitive and specific for label-free rapid direct DNA detection, promising a novel avenue for bio-sensing.
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Frank K, Paust S. Dynamic Natural Killer Cell and T Cell Responses to Influenza Infection. Front Cell Infect Microbiol 2020; 10:425. [PMID: 32974217 PMCID: PMC7461885 DOI: 10.3389/fcimb.2020.00425] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022] Open
Abstract
Influenza viruses have perplexed scientists for over a hundred years. Yearly vaccines limit their spread, but they do not prevent all infections. Therapeutic treatments for those experiencing severe infection are limited; further advances are held back by insufficient understanding of the fundamental immune mechanisms responsible for immunopathology. NK cells and T cells are essential in host responses to influenza infection. They produce immunomodulatory cytokines and mediate the cytotoxic response to infection. An imbalance in NK and T cell responses can lead to two outcomes: excessive inflammation and tissue damage or insufficient anti-viral functions and uncontrolled infection. The main cause of death in influenza patients is the former, mediated by hyperinflammatory responses termed “cytokine storm.” NK cells and T cells contribute to cytokine storm, but they are also required for viral clearance. Many studies have attempted to distinguish protective and pathogenic components of the NK cell and T cell influenza response, but it has become clear that they are dynamic and integrated processes. This review will analyze how NK cell and T cell effector functions during influenza infection affect the host response and correlate with morbidity and mortality outcomes.
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Affiliation(s)
- Kayla Frank
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States.,The Skaggs Graduate Program in Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA, United States
| | - Silke Paust
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States.,The Skaggs Graduate Program in Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA, United States
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Soday L, Lu Y, Albarnaz JD, Davies CTR, Antrobus R, Smith GL, Weekes MP. Quantitative Temporal Proteomic Analysis of Vaccinia Virus Infection Reveals Regulation of Histone Deacetylases by an Interferon Antagonist. Cell Rep 2020; 27:1920-1933.e7. [PMID: 31067474 PMCID: PMC6518873 DOI: 10.1016/j.celrep.2019.04.042] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 02/21/2019] [Accepted: 04/08/2019] [Indexed: 01/07/2023] Open
Abstract
Vaccinia virus (VACV) has numerous immune evasion strategies, including multiple mechanisms of inhibition of interferon regulatory factor 3 (IRF-3), nuclear factor κB (NF-κB), and type I interferon (IFN) signaling. Here, we use highly multiplexed proteomics to quantify ∼9,000 cellular proteins and ∼80% of viral proteins at seven time points throughout VACV infection. A total of 265 cellular proteins are downregulated >2-fold by VACV, including putative natural killer cell ligands and IFN-stimulated genes. Two-thirds of these viral targets, including class II histone deacetylase 5 (HDAC5), are degraded proteolytically during infection. In follow-up analysis, we demonstrate that HDAC5 restricts replication of both VACV and herpes simplex virus type 1. By generating a protein-based temporal classification of VACV gene expression, we identify protein C6, a multifunctional IFN antagonist, as being necessary and sufficient for proteasomal degradation of HDAC5. Our approach thus identifies both a host antiviral factor and a viral mechanism of innate immune evasion. Temporal proteomic analysis quantifies host and viral dynamics during vaccinia infection Host protein families are proteasomally degraded over the course of vaccinia infection Vaccinia protein C6 targets HDAC5 for proteasomal degradation HDAC5 is a host antiviral factor that restricts different families of DNA viruses
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Affiliation(s)
- Lior Soday
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Yongxu Lu
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Jonas D Albarnaz
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Colin T R Davies
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Geoffrey L Smith
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Michael P Weekes
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK.
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Punctuated Evolution of Myxoma Virus: Rapid and Disjunct Evolution of a Recent Viral Lineage in Australia. J Virol 2019; 93:JVI.01994-18. [PMID: 30728252 DOI: 10.1128/jvi.01994-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/23/2019] [Indexed: 11/20/2022] Open
Abstract
Myxoma virus (MYXV) has been evolving in a novel host species-European rabbits-in Australia since 1950. Previous studies of viruses sampled from 1950 to 1999 revealed a remarkably clock-like evolutionary process across all Australian lineages of MYXV. Through an analysis of 49 newly generated MYXV genome sequences isolated in Australia between 2008 and 2017, we show that MYXV evolution in Australia can be characterized by three lineages, one of which exhibited a greatly elevated rate of evolutionary change and a dramatic breakdown of temporal structure. Phylogenetic analysis revealed that this apparently punctuated evolutionary event occurred between 1996 and 2012. The branch leading to the rapidly evolving lineage contained a relatively high number of nonsynonymous substitutions, and viruses in this lineage reversed a mutation found in the progenitor standard laboratory strain (SLS) and all previous sequences that disrupts the reading frame of the M005L/R gene. Analysis of genes encoding proteins involved in DNA synthesis or RNA transcription did not reveal any mutations likely to cause rapid evolution. Although there was some evidence for recombination across the MYXV phylogeny, this was not associated with the increase in the evolutionary rate. The period from 1996 to 2012 saw significant declines in wild rabbit numbers, due to the introduction of rabbit hemorrhagic disease and prolonged drought in southeastern Australia, followed by the partial recovery of populations. It is therefore possible that a rapidly changing environment for virus transmission changed the selection pressures faced by MYXV, altering the course and pace of virus evolution.IMPORTANCE The coevolution of myxoma virus (MYXV) and European rabbits in Australia is one of the most important natural experiments in evolutionary biology, providing insights into virus adaptation to new hosts and the evolution of virulence. Previous studies of MYXV evolution have also shown that the virus evolves both relatively rapidly and in a strongly clock-like manner. Using newly acquired MYXV genome sequences from Australia, we show that the virus has experienced a dramatic change in evolutionary behavior over the last 20 years, with a breakdown in clock-like structure, the appearance of a rapidly evolving virus lineage, and the accumulation of multiple nonsynonymous and indel mutations. We suggest that this punctuated evolutionary event may reflect a change in selection pressures as rabbit numbers declined following the introduction of rabbit hemorrhagic disease virus and drought in the geographic regions inhabited by rabbits.
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Reverse Engineering Field Isolates of Myxoma Virus Demonstrates that Some Gene Disruptions or Losses of Function Do Not Explain Virulence Changes Observed in the Field. J Virol 2017; 91:JVI.01289-17. [PMID: 28768866 DOI: 10.1128/jvi.01289-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 07/27/2017] [Indexed: 01/16/2023] Open
Abstract
The coevolution of myxoma virus (MYXV) and wild European rabbits in Australia and Europe is a paradigm for the evolution of a pathogen in a new host species. Genomic analyses have identified the mutations that have characterized this evolutionary process, but defining causal mutations in the pathways from virulence to attenuation and back to virulence has not been possible. Using reverse genetics, we examined the roles of six selected mutations found in Australian field isolates of MYXV that fall in known or potential virulence genes. Several of these mutations occurred in genes previously identified as virulence genes in whole-gene knockout studies. Strikingly, no single or double mutation among the mutations tested had an appreciable impact on virulence. This suggests either that virulence evolution was defined by amino acid changes other than those analyzed here or that combinations of multiple mutations, possibly involving epistatic interactions or noncoding sequences, have been critical in the ongoing evolution of MYXV virulence. In sum, our results show that single-gene knockout studies of a progenitor virus can have little power to predict the impact of individual mutations seen in the field. The genetic determinants responsible for this canonical case of virulence evolution remain to be determined.IMPORTANCE The species jump of myxoma virus (MYXV) from the South American tapeti to the European rabbit populations of Australia and Europe is a canonical example of host-pathogen coevolution. Detailed molecular studies have identified multiple genes in MYXV that are critical for virulence, and genome sequencing has revealed the evolutionary history of MYXV in Australia and Europe. However, it has not been possible to categorically identify the key mutations responsible for the attenuation of or reversion to virulence during this evolutionary process. Here we use reverse genetics to examine the role of mutations in viruses isolated early and late in the Australian radiation of MYXV. Surprisingly, none of the candidate mutations that we identified as likely having roles in attenuation proved to be important for virulence. This indicates that considerable caution is warranted when interpreting the possible role of individual mutations during virulence evolution.
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10
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Next step in the ongoing arms race between myxoma virus and wild rabbits in Australia is a novel disease phenotype. Proc Natl Acad Sci U S A 2017; 114:9397-9402. [PMID: 28808019 DOI: 10.1073/pnas.1710336114] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In host-pathogen arms races, increases in host resistance prompt counteradaptation by pathogens, but the nature of that counteradaptation is seldom directly observed outside of laboratory models. The best-documented field example is the coevolution of myxoma virus (MYXV) in European rabbits. To understand how MYXV in Australia has continued to evolve in wild rabbits under intense selection for genetic resistance to myxomatosis, we compared the phenotypes of the progenitor MYXV and viral isolates from the 1950s and the 1990s in laboratory rabbits with no resistance. Strikingly, and unlike their 1950s counterparts, most virus isolates from the 1990s induced a highly lethal immune collapse syndrome similar to septic shock. Thus, the next step in this canonical case of coevolution after a species jump has been further escalation by the virus in the face of widespread host resistance.
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Kerr PJ, Cattadori IM, Rogers MB, Fitch A, Geber A, Liu J, Sim DG, Boag B, Eden JS, Ghedin E, Read AF, Holmes EC. Genomic and phenotypic characterization of myxoma virus from Great Britain reveals multiple evolutionary pathways distinct from those in Australia. PLoS Pathog 2017; 13:e1006252. [PMID: 28253375 PMCID: PMC5349684 DOI: 10.1371/journal.ppat.1006252] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/14/2017] [Accepted: 02/20/2017] [Indexed: 11/19/2022] Open
Abstract
The co-evolution of myxoma virus (MYXV) and the European rabbit occurred independently in Australia and Europe from different progenitor viruses. Although this is the canonical study of the evolution of virulence, whether the genomic and phenotypic outcomes of MYXV evolution in Europe mirror those observed in Australia is unknown. We addressed this question using viruses isolated in the United Kingdom early in the MYXV epizootic (1954-1955) and between 2008-2013. The later UK viruses fell into three distinct lineages indicative of a long period of separation and independent evolution. Although rates of evolutionary change were almost identical to those previously described for MYXV in Australia and strongly clock-like, genome evolution in the UK and Australia showed little convergence. The phenotypes of eight UK viruses from three lineages were characterized in laboratory rabbits and compared to the progenitor (release) Lausanne strain. Inferred virulence ranged from highly virulent (grade 1) to highly attenuated (grade 5). Two broad disease types were seen: cutaneous nodular myxomatosis characterized by multiple raised secondary cutaneous lesions, or an amyxomatous phenotype with few or no secondary lesions. A novel clinical outcome was acute death with pulmonary oedema and haemorrhage, often associated with bacteria in many tissues but an absence of inflammatory cells. Notably, reading frame disruptions in genes defined as essential for virulence in the progenitor Lausanne strain were compatible with the acquisition of high virulence. Combined, these data support a model of ongoing host-pathogen co-evolution in which multiple genetic pathways can produce successful outcomes in the field that involve both different virulence grades and disease phenotypes, with alterations in tissue tropism and disease mechanisms.
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Affiliation(s)
- Peter J. Kerr
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
- CSIRO Health and Biosecurity, Canberra, Australian Capital Territory 2601, Australia
| | - Isabella M. Cattadori
- Center for Infectious Disease Dynamics and Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States of America
| | - Matthew B. Rogers
- University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States of America
| | - Adam Fitch
- University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States of America
| | - Adam Geber
- Center for Genomics & Systems Biology, Department of Biology, New York University, New York, New York 10003, United States of America
| | - June Liu
- CSIRO Health and Biosecurity, Canberra, Australian Capital Territory 2601, Australia
| | - Derek G. Sim
- Center for Infectious Disease Dynamics and Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States of America
| | - Brian Boag
- The James Hutton Institute, Invergowrie, DD2 5DA, United Kingdom
| | - John-Sebastian Eden
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Elodie Ghedin
- Center for Genomics & Systems Biology, Department of Biology, New York University, New York, New York 10003, United States of America
| | - Andrew F. Read
- Center for Infectious Disease Dynamics and Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States of America
- Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States of America
| | - Edward C. Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
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Braun C, Thürmer A, Daniel R, Schultz AK, Bulla I, Schirrmeier H, Mayer D, Neubert A, Czerny CP. Genetic Variability of Myxoma Virus Genomes. J Virol 2017; 91:e01570-16. [PMID: 27903800 PMCID: PMC5286896 DOI: 10.1128/jvi.01570-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 11/18/2016] [Indexed: 12/12/2022] Open
Abstract
Myxomatosis is a recurrent problem on rabbit farms throughout Europe despite the success of vaccines. To identify gene variations of field and vaccine strains that may be responsible for changes in virulence, immunomodulation, and immunoprotection, the genomes of 6 myxoma virus (MYXV) strains were sequenced: German field isolates Munich-1, FLI-H, 2604, and 3207; vaccine strain MAV; and challenge strain ZA. The analyzed genomes ranged from 147.6 kb (strain MAV) to 161.8 kb (strain 3207). All sequences were affected by several mutations, covering 24 to 93 open reading frames (ORFs) and resulted in amino acid substitutions, insertions, or deletions. Only strains Munich-1 and MAV revealed the deletion of 10 ORFs (M007L to M015L) and 11 ORFs (M007L to M008.1L and M149R to M008.1R), respectively. Major differences were observed in the 27 immunomodulatory proteins encoded by MYXV. Compared to the reference strain Lausanne, strains FLI-H, 2604, 3207, and ZA showed the highest amino acid identity (>98.4%). In strains Munich-1 and MAV, deletion of 5 and 10 ORFs, respectively, was observed, encoding immunomodulatory proteins with ankyrin repeats or members of the family of serine protease inhibitors. Furthermore, putative immunodominant surface proteins with homology to vaccinia virus (VACV) were investigated in the sequenced strains. Only strain MAV revealed above-average frequencies of amino acid substitutions and frameshift mutations. Finally, we performed recombination analysis and found signs of recombination in vaccine strain MAV. Phylogenetic analysis showed a close relationship of strain MAV and the MSW strain of Californian MYXV. However, in a challenge model, strain MAV provided full protection against lethal challenges with strain ZA. IMPORTANCE Myxoma virus (MYXV) is pathogenic for European rabbits and two North American species. Due to sophisticated strategies in immune evasion and oncolysis, MYXV is an important model virus for immunological and pathological research. In its natural hosts, MYXV causes a benign infection, whereas in European rabbits, it causes the lethal disease myxomatosis. Since the introduction of MYXV into Australia and Europe for the biological control of European rabbits in the 1950s, a coevolution of host and pathogen has started, selecting for attenuated virus strains and increased resistance in rabbits. Evolution of viruses is a continuous process and influences the protective potential of vaccines. In our analyses, we sequenced 6 MYXV field, challenge, and vaccine strains. We focused on genes encoding proteins involved in virulence, host range, immunomodulation, and envelope composition. Genes affected most by mutations play a role in immunomodulation. However, attenuation cannot be linked to individual mutations or gene disruptions.
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Affiliation(s)
- Christoph Braun
- Department of Animal Sciences, Institute of Veterinary Medicine, Division of Microbiology and Animal Hygiene, Faculty of Agricultural Sciences, Georg August University Göttingen, Göttingen, Germany
| | - Andrea Thürmer
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg August University, Göttingen, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg August University, Göttingen, Germany
| | - Anne-Kathrin Schultz
- Department of Bioinformatics, Institute of Microbiology and Genetics, Georg August University, Göttingen, Germany
| | - Ingo Bulla
- Institute for Mathematics and Informatics, University of Greifswald, Greifswald, Germany
| | - Horst Schirrmeier
- Institute of Diagnostic Virology, Friedrich Loeffler Institut, Greifswald-Insel Riems, Germany
| | | | | | - Claus-Peter Czerny
- Department of Animal Sciences, Institute of Veterinary Medicine, Division of Microbiology and Animal Hygiene, Faculty of Agricultural Sciences, Georg August University Göttingen, Göttingen, Germany
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Williams KJN, Eaton HE, Jones L, Rengan S, Burshtyn DN. Vaccinia virus Western Reserve induces rapid surface expression of a host molecule detected by the antibody 4C7 that is distinct from CLEC2D. Microbiol Immunol 2016; 60:754-769. [PMID: 27862195 DOI: 10.1111/1348-0421.12451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/25/2016] [Accepted: 11/06/2016] [Indexed: 11/27/2022]
Abstract
In this study, the effect of active infection with vaccinia virus Western Reserve (VACV WR) on expression of C-type lectin domain family 2 (CLEC2D), a ligand of the human NK cell inhibitory receptor NKR-P1, was examined. As predicted, VACV infection led to a loss of CLEC2D mRNA in 221 cells, a B cell lymphoma line. Surprisingly, VACV infection of 221 cells caused a dramatic increase in cell surface staining for one CLEC2D-specific antibody, 4C7. There were no changes in other antibodies specific for CLEC2D and no indication that NK cells with NKR-P1A were inhibited, suggesting 4C7 detects a non-CLEC2D molecule following infection. The rapid increase in 4C7 signal requires virus attachment and is disrupted by UV treatment, but does not depend on new transcription or translation of either cellular or viral proteins. 4C7 does react with intracellular compartments, suggesting the molecule that is detected at the surface following infection is derived from an intracellular store. The phenomenon extends beyond lymphoid cells: it was observed in the non-human primate cell line Cos-7, but not with myxoma, a poxvirus distinct from VACV. To our knowledge, this is the first report of VACV or any poxvirus leading to rapid externalization of a host molecule. Among the VACV strains tested, the phenomenon was restricted to VACV WR and IHD-W, suggesting it has a virulence-, as opposed to a replication-related, function.
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Affiliation(s)
- Kinola J N Williams
- Department of Medical Microbiology and Immunology and Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Heather E Eaton
- Department of Medical Microbiology and Immunology and Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Lena Jones
- Department of Medical Microbiology and Immunology and Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Supraja Rengan
- Department of Medical Microbiology and Immunology and Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Deborah N Burshtyn
- Department of Medical Microbiology and Immunology and Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
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Targeting Swine Leukocyte Antigen Class I Molecules for Proteasomal Degradation by the nsp1α Replicase Protein of the Chinese Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Strain JXwn06. J Virol 2015; 90:682-93. [PMID: 26491168 DOI: 10.1128/jvi.02307-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/15/2015] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Porcine reproductive and respiratory syndrome virus (PRRSV) is a critical pathogen of swine, and infections by this virus often result in delayed, low-level induction of cytotoxic T lymphocyte (CTL) responses in pigs. Here, we report that a Chinese highly pathogenic PRRSV strain possessed the ability to downregulate swine leukocyte antigen class I (SLA-I) molecules on the cell surface of porcine alveolar macrophages and target them for degradation in a manner that was dependent on the ubiquitin-proteasome system. Moreover, we found that the nsp1α replicase protein contributed to this property of PRRSV. Further mutagenesis analyses revealed that this function of nsp1α required the intact molecule, including the zinc finger domain, but not the cysteine protease activity. More importantly, we found that nsp1α was able to interact with both chains of SLA-I, a requirement that is commonly needed for many viral proteins to target their cellular substrates for proteasomal degradation. Together, our findings provide critical insights into the mechanisms of how PRRSV might evade cellular immunity and also add a new role for nsp1α in PRRSV infection. IMPORTANCE PRRSV infections often result in delayed, low-level induction of CTL responses in pigs. Deregulation of this immunity is thought to prevent the virus from clearance in an efficient and timely manner, contributing to persistent infections in swineherds. Our studies in this report provide critical insight into the mechanism of how PRRSV might evade CTL responses. In addition, our findings add a new role for nsp1α, a critical viral factor involved in antagonizing host innate immunity.
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Kerr PJ, Liu J, Cattadori I, Ghedin E, Read AF, Holmes EC. Myxoma virus and the Leporipoxviruses: an evolutionary paradigm. Viruses 2015; 7:1020-61. [PMID: 25757062 PMCID: PMC4379559 DOI: 10.3390/v7031020] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/20/2015] [Accepted: 02/26/2015] [Indexed: 01/31/2023] Open
Abstract
Myxoma virus (MYXV) is the type species of the Leporipoxviruses, a genus of Chordopoxvirinae, double stranded DNA viruses, whose members infect leporids and squirrels, inducing cutaneous fibromas from which virus is mechanically transmitted by biting arthropods. However, in the European rabbit (Oryctolagus cuniculus), MYXV causes the lethal disease myxomatosis. The release of MYXV as a biological control for the wild European rabbit population in Australia, initiated one of the great experiments in evolution. The subsequent coevolution of MYXV and rabbits is a classic example of natural selection acting on virulence as a pathogen adapts to a novel host species. Slightly attenuated mutants of the progenitor virus were more readily transmitted by the mosquito vector because the infected rabbit survived longer, while highly attenuated viruses could be controlled by the rabbit immune response. As a consequence, moderately attenuated viruses came to dominate. This evolution of the virus was accompanied by selection for genetic resistance in the wild rabbit population, which may have created an ongoing co-evolutionary dynamic between resistance and virulence for efficient transmission. This natural experiment was repeated on a continental scale with the release of a separate strain of MYXV in France and its subsequent spread throughout Europe. The selection of attenuated strains of virus and resistant rabbits mirrored the experience in Australia in a very different environment, albeit with somewhat different rates. Genome sequencing of the progenitor virus and the early radiation, as well as those from the 1990s in Australia and Europe, has shown that although MYXV evolved at high rates there was no conserved route to attenuation or back to virulence. In contrast, it seems that these relatively large viral genomes have the flexibility for multiple pathways that converge on a similar phenotype.
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Affiliation(s)
- Peter J Kerr
- CSIRO Biosecurity Flagship, Black Mountain Laboratories, Clunies Ross Street, Acton, ACT 2601, Australia.
| | - June Liu
- CSIRO Biosecurity Flagship, Black Mountain Laboratories, Clunies Ross Street, Acton, ACT 2601, Australia.
| | - Isabella Cattadori
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA.
| | - Elodie Ghedin
- Center for Genomics and Systems Biology, Department of Biology and Global Institute of Public Health, New York University, New York, NY 10003, USA.
| | - Andrew F Read
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA.
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Biological Sciences, and Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia.
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16
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Maluquer de Motes C, Schiffner T, Sumner RP, Smith GL. Vaccinia virus virulence factor N1 can be ubiquitylated on multiple lysine residues. J Gen Virol 2014; 95:2038-2049. [PMID: 24914067 PMCID: PMC4135091 DOI: 10.1099/vir.0.065664-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Ubiquitylation is a covalent post-translational modification that regulates protein stability and is involved in many biological functions. Proteins may be modified with mono-ubiquitin or ubiquitin chains. Viruses have evolved multiple mechanisms to perturb the cell ubiquitin system and manipulate it to their own benefit. Here, we report ubiquitylation of vaccinia virus (VACV) protein N1. N1 is an inhibitor of the nuclear factor NF-κB and apoptosis that contributes to virulence, has a Bcl-2-like fold, and is highly conserved amongst orthopoxviruses. The interaction between N1 and ubiquitin occurs at endogenous protein levels during VACV infection and following ectopic expression of N1. Biochemical analysis demonstrated that N1 is covalently ubiquitylated, and heterodimers of ubiquitylated and non-ubiquitylated N1 monomers were identified, suggesting that ubiquitylation does not inhibit N1 dimerization. Studies with other VACV Bcl-2 proteins, such as C6 or B14, revealed that although these proteins also interact with ubiquitin, these interactions are non-covalent. Finally, mutagenesis of N1 showed that ubiquitylation occurs in a conventional lysine-dependent manner at multiple acceptor sites because only an N1 allele devoid of lysine residues remained unmodified. Taken together, we described a previously uncharacterized modification of the VACV protein N1 that provided a new layer of complexity to the biology of this virulence factor, and provided another example of the intricate interplay between poxviruses and the host ubiquitin system.
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Affiliation(s)
- Carlos Maluquer de Motes
- Department of Virology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK.,Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Torben Schiffner
- Department of Virology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Rebecca P Sumner
- Department of Virology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK.,Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Geoffrey L Smith
- Department of Virology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK.,Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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Alzhanova D, Hammarlund E, Reed J, Meermeier E, Rawlings S, Ray CA, Edwards DM, Bimber B, Legasse A, Planer S, Sprague J, Axthelm MK, Pickup DJ, Lewinsohn DM, Gold MC, Wong SW, Sacha JB, Slifka MK, Früh K. T cell inactivation by poxviral B22 family proteins increases viral virulence. PLoS Pathog 2014; 10:e1004123. [PMID: 24832205 PMCID: PMC4022744 DOI: 10.1371/journal.ppat.1004123] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 04/02/2014] [Indexed: 11/19/2022] Open
Abstract
Infections with monkeypox, cowpox and weaponized variola virus remain a threat to the increasingly unvaccinated human population, but little is known about their mechanisms of virulence and immune evasion. We now demonstrate that B22 proteins, encoded by the largest genes of these viruses, render human T cells unresponsive to stimulation of the T cell receptor by MHC-dependent antigen presentation or by MHC-independent stimulation. In contrast, stimuli that bypass TCR-signaling are not inhibited. In a non-human primate model of monkeypox, virus lacking the B22R homologue (MPXVΔ197) caused only mild disease with lower viremia and cutaneous pox lesions compared to wild type MPXV which caused high viremia, morbidity and mortality. Since MPXVΔ197-infected animals displayed accelerated T cell responses and less T cell dysregulation than MPXV US2003, we conclude that B22 family proteins cause viral virulence by suppressing T cell control of viral dissemination.
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Affiliation(s)
- Dina Alzhanova
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Erika Hammarlund
- Division of Neuroscience, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Jason Reed
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Erin Meermeier
- Department of Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
- Portland Veterans Administration Medical Center, Portland, Oregon, United States of America
| | - Stephanie Rawlings
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Caroline A. Ray
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - David M. Edwards
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Ben Bimber
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Alfred Legasse
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Shannon Planer
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Jerald Sprague
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Michael K. Axthelm
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - David J. Pickup
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - David M. Lewinsohn
- Department of Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
- Portland Veterans Administration Medical Center, Portland, Oregon, United States of America
| | - Marielle C. Gold
- Department of Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
- Portland Veterans Administration Medical Center, Portland, Oregon, United States of America
| | - Scott W. Wong
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Jonah B. Sacha
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Mark K. Slifka
- Division of Neuroscience, Oregon National Primate Research Center, Portland, Oregon, United States of America
| | - Klaus Früh
- Vaccine and Gene Therapy Institute, Oregon National Primate Research Center, Portland, Oregon, United States of America
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Portland, Oregon, United States of America
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18
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Genome scale evolution of myxoma virus reveals host-pathogen adaptation and rapid geographic spread. J Virol 2013; 87:12900-15. [PMID: 24067966 DOI: 10.1128/jvi.02060-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The evolutionary interplay between myxoma virus (MYXV) and the European rabbit (Oryctolagus cuniculus) following release of the virus in Australia in 1950 as a biological control is a classic example of host-pathogen coevolution. We present a detailed genomic and phylogeographic analysis of 30 strains of MYXV, including the Australian progenitor strain Standard Laboratory Strain (SLS), 24 Australian viruses isolated from 1951 to 1999, and three isolates from the early radiation in Britain from 1954 and 1955. We show that in Australia MYXV has spread rapidly on a spatial scale, with multiple lineages cocirculating within individual localities, and that both highly virulent and attenuated viruses were still present in the field through the 1990s. In addition, the detection of closely related virus lineages at sites 1,000 km apart suggests that MYXV moves freely in geographic space, with mosquitoes, fleas, and rabbit migration all providing means of transport. Strikingly, despite multiple introductions, all modern viruses appear to be ultimately derived from the original introductions of SLS. The rapidity of MYXV evolution was also apparent at the genomic scale, with gene duplications documented in a number of viruses. Duplication of potential virulence genes may be important in increasing the expression of virulence proteins and provides the basis for the evolution of novel functions. Mutations leading to loss of open reading frames were surprisingly frequent and in some cases may explain attenuation, but no common mutations that correlated with virulence or attenuation were identified.
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19
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Ogbomo H, Zemp FJ, Lun X, Zhang J, Stack D, Rahman MM, Mcfadden G, Mody CH, Forsyth PA. Myxoma virus infection promotes NK lysis of malignant gliomas in vitro and in vivo. PLoS One 2013; 8:e66825. [PMID: 23762498 PMCID: PMC3677932 DOI: 10.1371/journal.pone.0066825] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 05/12/2013] [Indexed: 11/19/2022] Open
Abstract
Myxoma virus (MYXV) is a well-established oncolytic agent against different types of tumors. MYXV is also known for its immunomodulatory properties in down-regulating major histocompatibility complex (MHC) I surface expression (via the M153R gene product, a viral E3-ubiquitin ligase) and suppressing T cell killing of infected target cells. MHC I down-regulation, however, favors NK cell activation. Brain tumors including gliomas are characterized by high MHC I expression with impaired NK activity. We thus hypothesized that MYXV infection of glioma cells will promote NK cell-mediated recognition and killing of gliomas. We infected human gliomas with MYXV and evaluated their susceptibility to NK cell-mediated cytotoxicity. MYXV enhanced NK cell-mediated killing of glioma cells (U87 cells, MYXV vs. Mock: 51.73% vs. 28.63%, P = .0001, t test; U251 cells, MYXV vs. Mock: 40.4% vs. 20.03%, P .0007, t test). Using MYXV M153R targeted knockout (designated vMyx-M153KO) to infect gliomas, we demonstrate that M153R was responsible for reduced expression of MHC I on gliomas and enhanced NK cell-mediated antiglioma activity (U87 cells, MYXV vs. vMyx-M153KO: 51.73% vs. 25.17%, P = .0002, t test; U251 cells, MYXV vs. vMyx-M153KO: 40.4% vs. 19.27, P = .0013, t test). Consequently, NK cell-mediated lysis of established human glioma tumors in CB-17 SCID mice was accelerated with improved mouse survival (log-rank P = .0072). These results demonstrate the potential for combining MYXV with NK cells to effectively kill malignant gliomas.
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Affiliation(s)
- Henry Ogbomo
- Departments of Oncology, Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
- Departments of Microbiology and Infectious Diseases, and Internal Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Franz J. Zemp
- Departments of Oncology, Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Xueqing Lun
- Departments of Oncology, Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Jiqing Zhang
- Departments of Oncology, Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Danuta Stack
- Departments of Microbiology and Infectious Diseases, and Internal Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Masmudur M. Rahman
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Grant Mcfadden
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Christopher H. Mody
- Departments of Microbiology and Infectious Diseases, and Internal Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Peter A. Forsyth
- Departments of Oncology, Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
- Department of NeuroOncology, Moffitt Cancer Center and University of Southern Florida, Tampa, Florida, United States of America
- * E-mail:
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20
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Correa RL, Bruckner FP, de Souza Cascardo R, Alfenas-Zerbini P. The Role of F-Box Proteins during Viral Infection. Int J Mol Sci 2013; 14:4030-49. [PMID: 23429191 PMCID: PMC3588083 DOI: 10.3390/ijms14024030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 12/14/2012] [Accepted: 01/17/2013] [Indexed: 01/10/2023] Open
Abstract
The F-box domain is a protein structural motif of about 50 amino acids that mediates protein–protein interactions. The F-box protein is one of the four components of the SCF (SKp1, Cullin, F-box protein) complex, which mediates ubiquitination of proteins targeted for degradation by the proteasome, playing an essential role in many cellular processes. Several discoveries have been made on the use of the ubiquitin–proteasome system by viruses of several families to complete their infection cycle. On the other hand, F-box proteins can be used in the defense response by the host. This review describes the role of F-box proteins and the use of the ubiquitin–proteasome system in virus–host interactions.
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Affiliation(s)
- Régis Lopes Correa
- Department of Genetics, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21944-970, Brazil; E-Mails: (R.L.C.); (R.S.C.)
| | - Fernanda Prieto Bruckner
- Department of Microbiology/BIOAGRO, Federal University of Viçosa, Viçosa, MG 36570-000, Brazil; E-Mail:
| | - Renan de Souza Cascardo
- Department of Genetics, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21944-970, Brazil; E-Mails: (R.L.C.); (R.S.C.)
- Department of Microbiology/BIOAGRO, Federal University of Viçosa, Viçosa, MG 36570-000, Brazil; E-Mail:
| | - Poliane Alfenas-Zerbini
- Department of Microbiology/BIOAGRO, Federal University of Viçosa, Viçosa, MG 36570-000, Brazil; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +55-31-3899-2955; Fax: +55-31-3899-2864
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Abstract
In recent years, our understanding of the role of natural killer (NK) cells in the response to viral infection has grown rapidly. Not only do we realize viruses have many immune-evasion strategies to escape NK cell responses, but that stimulation of NK cell subsets during an antiviral response occurs through receptors seemingly geared directly at viral products and that NK cells can provide a memory response to viral pathogens. Tremendous knowledge has been gained in this area through the study of herpes viruses, but appreciation for the significance of NK cells in the response to other types of viral infections is growing. The function of NK cells in defense against poxviruses has emerged over several decades beginning with the early seminal studies showing the role of NK cells and the NK gene complex in susceptibility of mouse strains to ectromelia, a poxvirus pathogen of mice. More recently, greater understanding has emerged of the molecular details of the response. Given that human diseases caused by poxviruses can be as lethal as smallpox or as benign as Molluscum contagiosum, and that vaccinia virus, the prototypic member of the pox family, persists as a mainstay of vaccine design and has potential as an oncolytic virus for tumor therapy, further research in this area remains important. This review focuses on recent advances in understanding the role of NK cells in the immune response to poxviruses, the receptors involved in activation of NK cells during poxvirus infection, and the viral evasion strategies poxviruses employ to avoid the NK response.
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Affiliation(s)
- Deborah N Burshtyn
- Department of Microbiology and Immunology, University of Alberta Edmonton, AB, Canada
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22
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Viral MHC class I inhibition evades CD8+ T-cell effector responses in vivo but not CD8+ T-cell priming. Proc Natl Acad Sci U S A 2012; 109:E3260-7. [PMID: 23112205 DOI: 10.1073/pnas.1217111109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although viral MHC class I inhibition is considered a classic immune-evasion strategy, its in vivo role is largely unclear. Mutant cowpox virus lacking its MHC class I inhibitors is markedly attenuated during acute infection because of CD8(+) T-cell-dependent control, but it was not known how CD8(+) T-cell responses are affected. Interestingly, we found no major effect of MHC class I down-regulation on priming of functional cowpox virus-specific CD8(+) T cells. Instead, we demonstrate that, during acute infection in vivo, MHC class I down-regulation prevents primed virus-specific CD8(+) T cells from recognizing infected cells and exerting effector responses to control the infection.
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23
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Kerr PJ, Ghedin E, DePasse JV, Fitch A, Cattadori IM, Hudson PJ, Tscharke DC, Read AF, Holmes EC. Evolutionary history and attenuation of myxoma virus on two continents. PLoS Pathog 2012; 8:e1002950. [PMID: 23055928 PMCID: PMC3464225 DOI: 10.1371/journal.ppat.1002950] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 08/22/2012] [Indexed: 01/05/2023] Open
Abstract
The attenuation of myxoma virus (MYXV) following its introduction as a biological control into the European rabbit populations of Australia and Europe is the canonical study of the evolution of virulence. However, the evolutionary genetics of this profound change in host-pathogen relationship is unknown. We describe the genome-scale evolution of MYXV covering a range of virulence grades sampled over 49 years from the parallel Australian and European epidemics, including the high-virulence progenitor strains released in the early 1950s. MYXV evolved rapidly over the sampling period, exhibiting one of the highest nucleotide substitution rates ever reported for a double-stranded DNA virus, and indicative of a relatively high mutation rate and/or a continually changing selective environment. Our comparative sequence data reveal that changes in virulence involved multiple genes, likely losses of gene function due to insertion-deletion events, and no mutations common to specific virulence grades. Hence, despite the similarity in selection pressures there are multiple genetic routes to attain either highly virulent or attenuated phenotypes in MYXV, resulting in convergence for phenotype but not genotype. The text-book example of the evolution of virulence is the attenuation of myxoma virus (MYXV) following its introduction as a biological control into the European rabbit populations of Australia and Europe in the 1950s. However, the key work on this topic, most notably by Frank Fenner and his colleagues, occurred before the availability of genome sequence data. The evolutionary genetic basis to the major changes in virulence in both the Australian and European epidemics is therefore largely unknown. We provide, for the first time, key details on the genome-wide changes that underpin this landmark example of pathogen emergence and virulence evolution. By sequencing and comparing MYXV genomes, including the original strains released in the 1950s, we show that (i) MYXV evolved rapidly in both Australia and Europe, producing one of the highest rates of evolutionary change ever recorded for a DNA virus, (ii) that changes in virulence were caused by mutations in multiple genes, often involving losses of gene function due to insertions and deletions, and that (iii) strains of the same virulence were defined by different mutations, such that both attenuated and virulent MYXV strains are produced by a variety genetic pathways, and generating convergent evolution for phenotype but not genotype.
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Affiliation(s)
- Peter J. Kerr
- CSIRO Ecosystem Sciences, Canberra, Australian Capital Territory, Australia
| | - Elodie Ghedin
- Center for Vaccine Research, Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jay V. DePasse
- Center for Vaccine Research, Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Adam Fitch
- Center for Vaccine Research, Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Isabella M. Cattadori
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Peter J. Hudson
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - David C. Tscharke
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Andrew F. Read
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Edward C. Holmes
- Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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24
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Kerr PJ. Myxomatosis in Australia and Europe: a model for emerging infectious diseases. Antiviral Res 2012; 93:387-415. [PMID: 22333483 DOI: 10.1016/j.antiviral.2012.01.009] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/20/2012] [Accepted: 01/26/2012] [Indexed: 11/18/2022]
Abstract
Myxoma virus is a poxvirus naturally found in two American leporid (rabbit) species (Sylvilagus brasiliensis and Sylvilagus bachmani) in which it causes an innocuous localised cutaneous fibroma. However, in European rabbits (Oryctolagus cuniculus) the same virus causes the lethal disseminated disease myxomatosis. The introduction of myxoma virus into the European rabbit population in Australia in 1950 initiated the best known example of what happens when a novel pathogen jumps into a completely naïve new mammalian host species. The short generation time of the rabbit and their vast numbers in Australia meant evolution could be studied in real time. The carefully documented emergence of attenuated strains of virus that were more effectively transmitted by the mosquito vector and the subsequent selection of rabbits with genetic resistance to myxomatosis is the paradigm for pathogen virulence and host-pathogen coevolution. This natural experiment was repeated with the release of a separate strain of myxoma virus in France in 1952. The subsequent spread of the virus throughout Europe and its coevolution with the rabbit essentially paralleled what occurred in Australia. Detailed molecular studies on myxoma virus have dissected the role of virulence genes in the pathogenesis of myxomatosis and when combined with genomic data and reverse genetics should in future enable the understanding of the molecular evolution of the virus as it adapted to its new host. This review describes the natural history and evolution of myxoma virus together with the molecular biology and experimental pathogenesis studies that are informing our understanding of evolution of emerging diseases.
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Affiliation(s)
- Peter J Kerr
- CSIRO Ecosystem Sciences, GPO Box 1700, Canberra, ACT 2601, Australia.
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Neurons are MHC class I-dependent targets for CD8 T cells upon neurotropic viral infection. PLoS Pathog 2011; 7:e1002393. [PMID: 22114563 PMCID: PMC3219726 DOI: 10.1371/journal.ppat.1002393] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 10/07/2011] [Indexed: 01/08/2023] Open
Abstract
Following infection of the central nervous system (CNS), the immune system is faced with the challenge of eliminating the pathogen without causing significant damage to neurons, which have limited capacities of renewal. In particular, it was thought that neurons were protected from direct attack by cytotoxic T lymphocytes (CTL) because they do not express major histocompatibility class I (MHC I) molecules, at least at steady state. To date, most of our current knowledge on the specifics of neuron-CTL interaction is based on studies artificially inducing MHC I expression on neurons, loading them with exogenous peptide and applying CTL clones or lines often differentiated in culture. Thus, much remains to be uncovered regarding the modalities of the interaction between infected neurons and antiviral CD8 T cells in the course of a natural disease. Here, we used the model of neuroinflammation caused by neurotropic Borna disease virus (BDV), in which virus-specific CTL have been demonstrated as the main immune effectors triggering disease. We tested the pathogenic properties of brain-isolated CD8 T cells against pure neuronal cultures infected with BDV. We observed that BDV infection of cortical neurons triggered a significant up regulation of MHC I molecules, rendering them susceptible to recognition by antiviral CTL, freshly isolated from the brains of acutely infected rats. Using real-time imaging, we analyzed the spatio-temporal relationships between neurons and CTL. Brain-isolated CTL exhibited a reduced mobility and established stable contacts with BDV-infected neurons, in an antigen- and MHC-dependent manner. This interaction induced rapid morphological changes of the neurons, without immediate killing or impairment of electrical activity. Early signs of neuronal apoptosis were detected only hours after this initial contact. Thus, our results show that infected neurons can be recognized efficiently by brain-isolated antiviral CD8 T cells and uncover the unusual modalities of CTL-induced neuronal damage. When a virus infects the brain, it is important to quickly block viral replication without causing excessive damage to neurons, which are not easily renewed. Cytotoxic T lymphocytes (CTL) are one of the main actors for virus elimination. However, the question of whether CTL are indeed capable of destroying infected neurons remains controversial. For this work, we analyzed the characteristics of interactions between infected neurons and CTL using neurotropic Borna disease virus (BDV). This virus infects neurons and triggers severe inflammation in the brain. We isolated CTL directly from the brains of rats infected with BDV and analyzed their interaction with primary cultures of neurons. Using live-cell fluorescence microscopy, we observed that CTL were arrested upon encounter with infected neurons and that they established stable contacts with them. Thereafter, infected neurons exhibited rapid changes in permeability but remained alive and electrically active for several hours, before ultimately being destroyed. Our study shows that neurons can indeed be recognized by CTL, an important observation for a better understanding of the physiopathology of virus-induced brain inflammation. In addition, it reveals that neurons are relatively resistant to CTL-induced killing, which may open a window of opportunity for new treatments.
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Camus-Bouclainville C, Gretillat M, Py R, Gelfi J, Guérin JL, Bertagnoli S. Genome sequence of SG33 strain and recombination between wild-type and vaccine myxoma viruses. Emerg Infect Dis 2011; 17:633-8. [PMID: 21470452 PMCID: PMC3377406 DOI: 10.3201/eid1704.101146] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Myxomatosis in Europe is the result of the release of a South America strain of myxoma virus in 1952. Several attenuated strains with origins in South America or California have since been used as vaccines in the rabbit industry. We sequenced the genome of the SG33 myxoma virus vaccine strain and compared it with those of other myxoma virus strains. We show that SG33 genome carries a large deletion in its right end. Furthermore, our data strongly suggest that the virus isolate from which SG33 is derived results from an in vivo recombination between a wild-type South America (Lausanne) strain and a California MSD-derived strain. These findings raise questions about the use of insufficiently attenuated virus in vaccination.
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Spiesschaert B, McFadden G, Hermans K, Nauwynck H, Van de Walle GR. The current status and future directions of myxoma virus, a master in immune evasion. Vet Res 2011; 42:76. [PMID: 21658227 PMCID: PMC3131250 DOI: 10.1186/1297-9716-42-76] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 06/09/2011] [Indexed: 01/12/2023] Open
Abstract
Myxoma virus (MYXV) gained importance throughout the twentieth century because of the use of the highly virulent Standard Laboratory Strain (SLS) by the Australian government in the attempt to control the feral Australian population of Oryctolagus cuniculus (European rabbit) and the subsequent illegal release of MYXV in Europe. In the European rabbit, MYXV causes a disease with an exceedingly high mortality rate, named myxomatosis, which is passively transmitted by biting arthropod vectors. MYXV still has a great impact on European rabbit populations around the world. In contrast, only a single cutaneous lesion, restricted to the point of inoculation, is seen in its natural long-term host, the South-American Sylvilagus brasiliensis and the North-American S. Bachmani. Apart from being detrimental for European rabbits, however, MYXV has also become of interest in human medicine in the last two decades for two reasons. Firstly, due to the strong immune suppressing effects of certain MYXV proteins, several secreted virus-encoded immunomodulators (e.g. Serp-1) are being developed to treat systemic inflammatory syndromes such as cardiovascular disease in humans. Secondly, due to the inherent ability of MYXV to infect a broad spectrum of human cancer cells, the live virus is also being developed as an oncolytic virotherapeutic to treat human cancer. In this review, an update will be given on the current status of MYXV in rabbits as well as its potential in human medicine in the twenty-first century. Table of contents Abstract 1. The virus 2. History 3. Pathogenesis and disease symptoms 4. Immunomodulatory proteins of MYXV 4.1. MYXV proteins with anti-apoptotic functions 4.1.1. Inhibition of pro-apoptotic molecules 4.1.2. Inhibition by protein-protein interactions by ankyrin repeat viral proteins 4.1.3. Inhibition of apoptosis by enhancing the degradation of cellular proteins 4.1.4. Inhibition of apoptosis by blocking host Protein Kinase R (PKR) 4.2. MYXV proteins interfering with leukocyte chemotaxis 4.3. MYXV serpins that inhibit cellular pro-inflammatory or pro-apoptotic proteases 4.4. MYXV proteins that interfere with leukocyte activation 4.5. MYXV proteins with sequence similarity to HIV proteins 4.6. MYXV proteins with unknown immune function 5. Vaccination strategies against myxomatosis 5.1. Current MYXV vaccines 5.2. Vaccination campaigns to protect European rabbits in the wild 6. Applications of myxoma virus for human medicine 6.1. MYXV proteins as therapeutics for allograft vasculopathy and atherosclerosis 6.2. Applications for MYXV as a live oncolytic virus to treat cancer 7. Discussion and Conclusions 8. List of Abbreviations References Author Details Authors' contributions Competing interests Figure Legends Acknowledgements
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Affiliation(s)
- Bart Spiesschaert
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
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Bartee E, Eyster CA, Viswanathan K, Mansouri M, Donaldson JG, Früh K. Membrane-Associated RING-CH proteins associate with Bap31 and target CD81 and CD44 to lysosomes. PLoS One 2010; 5:e15132. [PMID: 21151997 PMCID: PMC2996310 DOI: 10.1371/journal.pone.0015132] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 10/25/2010] [Indexed: 02/03/2023] Open
Abstract
Membrane-associated RING-CH (MARCH) proteins represent a family of transmembrane ubiquitin ligases modulating intracellular trafficking and turnover of transmembrane protein targets. While homologous proteins encoded by gamma-2 herpesviruses and leporipoxviruses have been studied extensively, limited information is available regarding the physiological targets of cellular MARCH proteins. To identify host cell proteins targeted by the human MARCH-VIII ubiquitin ligase we used stable isotope labeling of amino-acids in cell culture (SILAC) to monitor MARCH-dependent changes in the membrane proteomes of human fibroblasts. Unexpectedly, we observed that MARCH-VIII reduced the surface expression of Bap31, a chaperone that predominantly resides in the endoplasmic reticulum (ER). We demonstrate that Bap31 associates with the transmembrane domains of several MARCH proteins and controls intracellular transport of MARCH proteins. In addition, we observed that MARCH-VIII reduced the surface expression of the hyaluronic acid-receptor CD44 and both MARCH-VIII and MARCH-IV sequestered the tetraspanin CD81 in endo-lysosomal vesicles. Moreover, gene knockdown of MARCH-IV increased surface levels of endogenous CD81 suggesting a constitutive involvement of this family of ubiquitin ligases in the turnover of tetraspanins. Our data thus suggest a role of MARCH-VIII and MARCH-IV in the regulated turnover of CD81 and CD44, two ubiquitously expressed, multifunctional proteins.
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Affiliation(s)
- Eric Bartee
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Craig A. Eyster
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, Maryland, United States of America
| | - Kasinath Viswanathan
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Mandana Mansouri
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Julie G. Donaldson
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, Maryland, United States of America
| | - Klaus Früh
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
- * E-mail:
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Barry M, van Buuren N, Burles K, Mottet K, Wang Q, Teale A. Poxvirus exploitation of the ubiquitin-proteasome system. Viruses 2010; 2:2356-2380. [PMID: 21994622 PMCID: PMC3185573 DOI: 10.3390/v2102356] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 09/27/2010] [Accepted: 09/30/2010] [Indexed: 12/19/2022] Open
Abstract
Ubiquitination plays a critical role in many cellular processes. A growing number of viruses have evolved strategies to exploit the ubiquitin-proteasome system, including members of the Poxviridae family. Members of the poxvirus family have recently been shown to encode BTB/kelch and ankyrin/F-box proteins that interact with cullin-3 and cullin-1 based ubiquitin ligases, respectively. Multiple members of the poxvirus family also encode ubiquitin ligases with intrinsic activity. This review describes the numerous mechanisms that poxviruses employ to manipulate the ubiquitin-proteasome system.
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Affiliation(s)
- Michele Barry
- Author to whom correspondence should be addressed: E-Mail: ; Tel.: +1 780 492-0702; Fax: +1 780 492-7521
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Liu J, Wennier S, McFadden G. The immunoregulatory properties of oncolytic myxoma virus and their implications in therapeutics. Microbes Infect 2010; 12:1144-52. [PMID: 20832500 DOI: 10.1016/j.micinf.2010.08.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 08/30/2010] [Accepted: 08/31/2010] [Indexed: 12/20/2022]
Abstract
Myxoma virus (MYXV) is a poxvirus with a strict rabbit-specific host-tropism for pathogenesis. The immunoregulatory factors encoded by MYXV can suppress some functions of immune effectors from other species. We review their mechanisms of action, implications in therapeutics and the potential to improve MYXV as an oncolytic agent in humans.
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Affiliation(s)
- Jia Liu
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, 1600 SW Archer Rd, P.O. box 100266, Gainesville, FL 32610, USA
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31
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Two mechanistically distinct immune evasion proteins of cowpox virus combine to avoid antiviral CD8 T cells. Cell Host Microbe 2010; 6:422-32. [PMID: 19917497 DOI: 10.1016/j.chom.2009.09.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 08/07/2009] [Accepted: 09/30/2009] [Indexed: 01/06/2023]
Abstract
Downregulation of MHC class I on the cell surface is an immune evasion mechanism shared by many DNA viruses, including cowpox virus. Previously, a cowpox virus protein, CPXV203, was shown to downregulate MHC class I. Here we report that CPXV12 is the only other MHC class I-regulating protein of cowpox virus and that it uses a mechanism distinct from that of CPXV203. Whereas CPXV203 retains fully assembled MHC class I by exploiting the KDEL-mediated endoplasmic reticulum retention pathway, CPXV12 binds to the peptide-loading complex and inhibits peptide loading on MHC class I molecules. Viruses deleted of both CPXV12 and CPXV203 demonstrated attenuated virulence in a CD8 T cell-dependent manner. These data demonstrate that CPXV12 and CPXV203 proteins combine to ablate MHC class I expression and abrogate antiviral CD8 T cell responses.
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Cavadini P, Botti G, Barbieri I, Lavazza A, Capucci L. Molecular characterization of SG33 and Borghi vaccines used against myxomatosis. Vaccine 2010; 28:5414-20. [DOI: 10.1016/j.vaccine.2010.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 05/06/2010] [Accepted: 06/04/2010] [Indexed: 11/25/2022]
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The myxoma virus m-t5 ankyrin repeat host range protein is a novel adaptor that coordinately links the cellular signaling pathways mediated by Akt and Skp1 in virus-infected cells. J Virol 2009; 83:12068-83. [PMID: 19776120 DOI: 10.1128/jvi.00963-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Most poxviruses express multiple proteins containing ankyrin (ANK) repeats accounting for a large superfamily of related but unique determinants of poxviral tropism. Recently, select members of this novel family of poxvirus proteins have drawn considerable attention for their potential roles in modulating intracellular signaling networks during viral infection. The rabbit-specific poxvirus, myxoma virus (MYXV), encodes four unique ANK repeat proteins, termed M-T5, M148, M149, and M150, all of which include a carboxy-terminal PRANC domain which closely resembles a cellular protein motif called the F-box domain. Here, we show that each MYXV-encoded ANK repeat protein, including M-T5, interacts directly with the Skp1 component of the host SCF ubiquitin ligase complex, and that the binding of M-T5 to cullin 1 is indirect via binding to Skp1 in the host SCF complex. To understand the significance of these virus-host protein interactions, the various binding domains of M-T5 were mapped. The N-terminal ANK repeats I and II were identified as being important for interaction with Akt, whereas the C-terminal PRANC/F-box-like domain was essential for binding to Skp1. We also report that M-T5 can bind Akt and the host SCF complex (via Skp1) simultaneously in MYXV-infected cells. Finally, we report that M-T5 specifically mediates the relocalization of Akt from the nucleus to the cytoplasm during infection with the wild-type MYXV, but not the M-T5 knockout version of the virus. These results indicate that ANK/PRANC proteins play a critical role in reprogramming disparate cellular signaling cascades to establish a new cellular environment more favorable for virus replication.
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35
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Interplay between poxviruses and the cellular ubiquitin/ubiquitin-like pathways. FEBS Lett 2009; 583:607-14. [PMID: 19174161 DOI: 10.1016/j.febslet.2009.01.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 01/15/2009] [Accepted: 01/18/2009] [Indexed: 02/06/2023]
Abstract
Post-translational polypeptide tagging by conjugation with ubiquitin and ubiquitin-like (Ub/Ubl) molecules is a potent way to alter protein functions and/or sort specific protein targets to the proteasome for degradation. Many poxviruses interfere with the host Ub/Ubl system by encoding viral proteins that can usurp this pathway. Some of these include viral proteins of the membrane-associated RING-CH (MARCH) domain, p28/Really Interesting New Gene (RING) finger, ankyrin-repeat/F-box and Broad-complex, Tramtrack and Bric-a-Brac (BTB)/Kelch subgroups of the E3 Ub ligase superfamily. Here we describe and discuss the various strategies used by poxviruses to target and subvert the host cell Ub/Ubl systems.
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36
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Orthopoxviruses require a functional ubiquitin-proteasome system for productive replication. J Virol 2008; 83:2099-108. [PMID: 19109393 DOI: 10.1128/jvi.01753-08] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cellular homeostasis depends on an intricate balance of protein expression and degradation. The ubiquitin-proteasome pathway plays a crucial role in specifically targeting proteins tagged with ubiquitin for destruction. This degradation can be effectively blocked by both chemically synthesized and natural proteasome inhibitors. Poxviruses encode a number of proteins that exploit the ubiquitin-proteasome system, including virally encoded ubiquitin molecules and ubiquitin ligases, as well as BTB/kelch proteins and F-box proteins, which interact with cellular ubiquitin ligases. Here we show that poxvirus infection was dramatically affected by a range of proteasome inhibitors, including MG132, MG115, lactacystin, and bortezomib (Velcade). Confocal microscopy demonstrated that infected cells treated with MG132 or bortezomib lacked viral replication factories within the cytoplasm. This was accompanied by the absence of late gene expression and DNA replication; however, early gene expression occurred unabated. Proteasomal inhibition with MG132 or bortezomib also had dramatic effects on viral titers, severely blocking viral replication and propagation. The effects of MG132 on poxvirus infection were reversible upon washout, resulting in the production of late genes and viral replication factories. Significantly, the addition of an ubiquitin-activating enzyme (E1) inhibitor had a similar affect on late and early protein expression. Together, our data suggests that a functional ubiquitin-proteasome system is required during poxvirus infection.
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Peng YT, Chaung HC, Chang HL, Chang HC, Chung WB. Modulations of phenotype and cytokine expression of porcine bone marrow-derived dendritic cells by porcine reproductive and respiratory syndrome virus. Vet Microbiol 2008; 136:359-65. [PMID: 19128898 DOI: 10.1016/j.vetmic.2008.11.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 11/19/2008] [Accepted: 11/24/2008] [Indexed: 12/13/2022]
Abstract
Phenotypic and functional property changes of bone marrow-derived immature dendritic cells (BM-imDCs) after porcine reproductive and respiratory syndrome virus (PRRSV) infection have been detailed in a previous report. A down-regulated expression of MHC I molecules along with an up-regulated expression of CD80/86 were observed in BM-imDCs after the exposure to PRRSV. In this study, we further investigate the expression of surface phenotypes of BM-imDCs in relation to their infection status. Exposure of PRRSV to BM-imDCs resulted in a down-regulated expression of MHC I and an up-regulated expression of CD80/86 in infected cells, as demonstrated by significant alterations in both percentage of expressing cells and mean fluorescence intensity (MFI) in PRRSV-positive cells. A significant suppression in MFI of MHC I and an increase in percentage of cells expressing CD80/86 were observed in noninfected bystander cells. We also demonstrated that exposure of BM-imDCs to PRRSV resulted in a significantly increased secretion of IL-1, IL-6, IL-8, IL-10 and IFN-gamma but not IL-12 or TNF-alpha. In addition, the PRRSV infection modulates cytokine expressions of BM-imDCs through their response to microbial pathogen-associated molecular patterns. These results will prove helpful in clarification of the factors that mediate host defense against PRRSV, as well as the possible interaction mechanisms between PRRSV and other microbes in the pathogenesis of PRRSV infection in pigs.
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Affiliation(s)
- Yu-Tang Peng
- Department of Veterinary Medicine, National Pingtung University of Science and Technology, Neipu, Pingtung 912, Taiwan, ROC
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Ectromelia virus encodes a novel family of F-box proteins that interact with the SCF complex. J Virol 2008; 82:9917-27. [PMID: 18684824 DOI: 10.1128/jvi.00953-08] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Poxviruses are notorious for encoding multiple proteins that regulate cellular signaling pathways, including the ubiquitin-proteasome system. Bioinformatics indicated that ectromelia virus, the causative agent of lethal mousepox, encoded four proteins, EVM002, EVM005, EVM154, and EVM165, containing putative F-box domains. In contrast to cellular F-box proteins, the ectromelia virus proteins contain C-terminal F-box domains in conjunction with N-terminal ankyrin repeats, a combination that has not been previously reported for cellular proteins. These observations suggested that the ectromelia virus F-box proteins interact with SCF (Skp1, cullin-1, and F-box) ubiquitin ligases. We focused our studies on EVM005, since this protein had only one ortholog in cowpox virus. Using mass spectrometry, we identified cullin-1 as a binding partner for EVM005, and this interaction was confirmed by overexpression of hemagglutinin (HA)-cullin-1. During infection, Flag-EVM005 and HA-cullin-1 colocalized to distinct cellular bodies. Significantly, EVM005 coprecipitated with endogenous Skp1, cullin-1, and Roc1 and associated with conjugated ubiquitin, suggesting that EVM005 interacted with the components of a functional ubiquitin ligase. Interaction of EVM005 with cullin-1 and Skp1 was abolished upon deletion of the F-box, indicating that the F-box played a crucial role in interaction with the SCF complex. Additionally, EVM002 and EVM154 interacted with Skp1 and conjugated ubiquitin, suggesting that ectromelia virus encodes multiple F-box-containing proteins that regulate the SCF complex. Our results indicate that ectromelia virus has evolved multiple proteins that interact with the SCF complex.
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39
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Remodeling of endothelial adherens junctions by Kaposi's sarcoma-associated herpesvirus. J Virol 2008; 82:9615-28. [PMID: 18667499 DOI: 10.1128/jvi.02633-07] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Vascular endothelial cadherin (VE-cadherin) connects neighboring endothelial cells (ECs) via interendothelial junctions and regulates EC proliferation and adhesion during vasculogenesis and angiogenesis. The cytoplasmic domain of VE-cadherin recruits alpha- and beta-catenins and gamma-catenin, which interact with the actin cytoskeleton, thus modulating cell morphology. Dysregulation of the adherens junction/cytoskeletal axis is a hallmark of invasive tumors. We now demonstrate that the transmembrane ubiquitin ligase K5/MIR-2 of Kaposi's sarcoma-associated herpesvirus targets VE-cadherin for ubiquitin-mediated destruction, thus disturbing EC adhesion. In contrast, N-cadherin levels in K5-expressing cells were increased compared to those in control cells. Steady-state levels of alpha- and beta-catenins and gamma-catenin in K5-expressing ECs were drastically reduced due to proteasomal destruction. Moreover, the actin cytoskeleton was rearranged, resulting in the dysregulation of EC barrier function as measured by electric cell-substrate impedance sensing. Our data represent the first example of a viral protein targeting adherens junction proteins and suggest that K5 contributes to EC proliferation, vascular leakage, and the reprogramming of the EC proteome during Kaposi's sarcoma tumorigenesis.
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Pignolet B, Boullier S, Gelfi J, Bozzetti M, Russo P, Foulon E, Meyer G, Delverdier M, Foucras G, Bertagnoli S. Safety and immunogenicity of myxoma virus as a new viral vector for small ruminants. J Gen Virol 2008; 89:1371-1379. [PMID: 18474552 DOI: 10.1099/vir.0.83595-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myxoma virus (MYXV), a leporide-specific poxvirus, represents an attractive candidate for the generation of safe and non-replicative vaccine vectors for other species. With the aim of developing new recombinant vaccines for ruminants, we evaluated the safety and the immunogenicity of recombinant MYXV in sheep. In vitro studies indicated that ovine primary fibroblasts were not permissive for MYXV and that infection of ovine peripheral blood mononuclear cells occurred at a low rate. Although non-specific activation significantly improved the susceptibility of lymphocytes, MYXV infection remained abortive. Histological and immunohistochemical examination at the inoculation sites revealed the development of an inflammatory process and allowed the detection of sparse infected cells in the dermis. In addition, inoculated sheep developed an antibody response directed against MYXV and the product of the transgene. Overall, these results provide the first line of evidence on the potential of MYXV as a viral vector for ruminants.
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Affiliation(s)
- Béatrice Pignolet
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
| | - Séverine Boullier
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
| | - Jacqueline Gelfi
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
| | - Marjorie Bozzetti
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
| | - Pierre Russo
- AFSSA LERPRA les Templiers, 105 route des Chappes, F-06902 Sophia Antipolis, France
| | - Eliane Foulon
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
| | - Gilles Meyer
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
| | - Maxence Delverdier
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
| | - Gilles Foucras
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
| | - Stéphane Bertagnoli
- Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.,INRA, UMR 1225, F-31076 Toulouse, France
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41
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Ectromelia virus BTB/kelch proteins, EVM150 and EVM167, interact with cullin-3-based ubiquitin ligases. Virology 2008; 374:82-99. [PMID: 18221766 DOI: 10.1016/j.virol.2007.11.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 09/27/2007] [Accepted: 11/29/2007] [Indexed: 11/23/2022]
Abstract
Cellular proteins containing BTB and kelch domains have been shown to function as adapters for the recruitment of substrates to cullin-3-based ubiquitin ligases. Poxviruses are the only family of viruses known to encode multiple BTB/kelch proteins, suggesting that poxviruses may modulate the ubiquitin pathway through interaction with cullin-3. Ectromelia virus encodes four BTB/kelch proteins and one BTB-only protein. Here we demonstrate that two of the ectromelia virus-encoded BTB/kelch proteins, EVM150 and EVM167, interacted with cullin-3. Similar to cellular BTB proteins, the BTB domain of EVM150 and EVM167 was necessary and sufficient for cullin-3 interaction. During infection, EVM150 and EVM167 localized to discrete cytoplasmic regions, which co-localized with cullin-3. Furthermore, EVM150 and EVM167 co-localized and interacted with conjugated ubiquitin, as demonstrated by confocal microscopy and co-immunoprecipitation. Our findings suggest that the ectromelia virus-encoded BTB/kelch proteins, EVM150 and EVM167, interact with cullin-3 potentially functioning to recruit unidentified substrates for ubiquitination.
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42
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Byun M, Wang X, Pak M, Hansen TH, Yokoyama WM. Cowpox virus exploits the endoplasmic reticulum retention pathway to inhibit MHC class I transport to the cell surface. Cell Host Microbe 2007; 2:306-15. [PMID: 18005752 DOI: 10.1016/j.chom.2007.09.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 08/13/2007] [Accepted: 09/07/2007] [Indexed: 11/20/2022]
Abstract
Major histocompatibility complex (MHC) class I molecules assemble with peptides in the ER lumen and are transported via Golgi to the plasma membrane for recognition by T cells. Inhibiting MHC assembly, transport, and surface expression are common viral strategies of evading immune recognition. Cowpox virus, a clinically relevant orthopoxvirus, downregulates MHC class I expression on infected cells. However, the viral protein(s) and mechanisms responsible are unknown. We identify CPXV203 as a cowpox virus protein that associates with fully assembled MHC class I molecules and blocks their transport through the Golgi. A C-terminal KTEL motif in CPXV203 closely resembles the canonical ER retention motif KDEL and is required for CPXV203 function, indicating that a physiologic pathway is exploited to retain MHC class I in the ER. This viral mechanism for MHC class I downregulation may explain virulence differences between clinical isolates of orthopoxviruses.
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Affiliation(s)
- Minji Byun
- Howard Hughes Medical Institute, Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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43
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Balinsky CA, Delhon G, Afonso CL, Risatti GR, Borca MV, French RA, Tulman ER, Geary SJ, Rock DL. Sheeppox virus kelch-like gene SPPV-019 affects virus virulence. J Virol 2007; 81:11392-401. [PMID: 17686843 PMCID: PMC2045533 DOI: 10.1128/jvi.01093-07] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sheeppox virus (SPPV), a member of the Capripoxvirus genus of the Poxviridae, is the etiologic agent of a significant disease of sheep in the developing world. Genomic analysis of pathogenic and vaccine capripoxviruses identified genes with potential roles in virulence and host range, including three genes with similarity to kelch-like genes of other poxviruses and eukaryotes. Here, a mutant SPPV with a deletion in the SPPV-019 kelch-like gene, DeltaKLP, was derived from the pathogenic strain SPPV-SA. DeltaKLP exhibited in vitro growth characteristics similar to those of SPPV-SA and revertant virus (RvKLP). DeltaKLP-infected cells exhibited a reduction in Ca(2+)-independent cell adhesion, suggesting that SPPV-019 may modulate cellular adhesion. When inoculated in sheep by the intranasal or intradermal routes, DeltaKLP was markedly attenuated, since all DeltaKLP-infected lambs survived infection. In contrast, SPPV-SA and RvKLP induced mortality approaching 100%. Lambs inoculated with DeltaKLP exhibited marked reduction or delay in fever response, gross lesions, viremia, and virus shedding compared to parental and revertant viruses. Together, these findings indicate that SPPV-019 is a significant SPPV virulence determinant in sheep.
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Affiliation(s)
- C A Balinsky
- Center of Excellence for Vaccine Research, University of Connecticut, Storrs, Connecticut 06269, USA
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44
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Dasgupta A, Hammarlund E, Slifka MK, Früh K. Cowpox virus evades CTL recognition and inhibits the intracellular transport of MHC class I molecules. THE JOURNAL OF IMMUNOLOGY 2007; 178:1654-61. [PMID: 17237415 DOI: 10.4049/jimmunol.178.3.1654] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Orthopoxviruses evade host immune responses by using a number of strategies, including decoy chemokine receptors, regulation of apoptosis, and evasion of complement-mediated lysis. Different from other poxviral subfamilies, however, orthopoxviruses are not known to evade recognition by CTL. In fact, vaccinia virus (VV) is used as a vaccine against smallpox and a vector for eliciting strong T cell responses to foreign Ags. and both human and mouse T cells are readily stimulated by VV-infected APC in vitro. Surprisingly, however, CD8(+) T cells of mice infected with cowpox virus (CPV) or VV recognized APC infected with VV but not APC infected with CPV. Likewise, CD8(+) T cells from vaccinated human subjects could not be activated by CPV-infected targets and CPV prevented the recognition of VV-infected APC upon coinfection. Because CD8(+) T cells recognize viral peptides presented by MHC class I (MHC I), we examined surface expression, total levels, and intracellular maturation of MHC I in CPV- and VV-infected human and mouse cells. Although total levels of MHC I were unchanged, CPV reduced surface levels and inhibited the intracellular transport of MHC I early during infection. CPV did not prevent peptide loading of MHC I but completely inhibited MHC I exit from the endoplasmic reticulum. Because this inhibition was independent of viral replication, we conclude that an early gene product of CPV abrogates MHC I trafficking, thus rendering CPV-infected cells "invisible" to T cells. The absence of this immune evasion mechanism in VV likely limits virulence without compromising immunogenicity.
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Affiliation(s)
- Anindya Dasgupta
- Oregon Health and Science University, Vaccine and Gene Therapy Institute, Beaverton, OR 97006, USA
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45
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Stanford MM, Werden SJ, McFadden G. Myxoma virus in the European rabbit: interactions between the virus and its susceptible host. Vet Res 2007; 38:299-318. [PMID: 17296158 DOI: 10.1051/vetres:2006054] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Accepted: 06/20/2006] [Indexed: 02/01/2023] Open
Abstract
Myxoma virus (MV) is a poxvirus that evolved in Sylvilagus lagomorphs, and is the causative agent of myxomatosis in European rabbits (Oryctolagus cuniculus). This virus is not a natural pathogen of O. cuniculus, yet is able to subvert the host rabbit immune system defenses and cause a highly lethal systemic infection. The interaction of MV proteins and the rabbit immune system has been an ideal model to help elucidate host/poxvirus interactions, and has led to a greater understanding of how other poxvirus pathogens are able to cause disease in their respective hosts. This review will examine how MV causes myxomatosis, by examining a selection of the identified immunomodulatory proteins that this virus expresses to subvert the immune and inflammatory pathways of infected rabbit hosts.
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Affiliation(s)
- Marianne M Stanford
- Biotherapeutics Research Group, Robarts Research Institute, University of Western Ontario, Siebens-Drake Building, Room 126, 1400 Western Road, London, Ontario, N6G 2V4, Canada
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46
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Bartee E, McCormack A, Früh K. Quantitative membrane proteomics reveals new cellular targets of viral immune modulators. PLoS Pathog 2007; 2:e107. [PMID: 17238276 PMCID: PMC1626102 DOI: 10.1371/journal.ppat.0020107] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Accepted: 09/05/2006] [Indexed: 12/18/2022] Open
Abstract
Immunomodulators of pathogens frequently affect multiple cellular targets, thus preventing recognition by different immune cells. For instance, the K5 modulator of immune recognition (MIR2) from Kaposi sarcoma-associated herpesvirus prevents activation of cytotoxic T cells, natural killer cells, and natural killer T cells by downregulating major histocompatibility complex (MHC) class I molecules, the MHC-like molecule CD1, the cell adhesion molecules ICAM-1 and PECAM, and the co-stimulatory molecule B7.2. K5 belongs to a family of viral- and cellular-membrane-spanning RING ubiquitin ligases. While a limited number of transmembrane proteins have been shown to be targeted for degradation by this family, it is unknown whether additional targets exist. We now describe a quantitative proteomics approach to identify novel targets of this protein family. Using stable isotope labeling by amino acids, we compared the proteome of plasma, Golgi, and endoplasmic reticulum membranes in the presence and absence of K5. Mass spectrometric protein identification revealed four proteins that were consistently underrepresented in the plasma membrane of K5 expression cells: MHC I (as expected), bone marrow stromal antigen 2 (BST-2, CD316), activated leukocyte cell adhesion molecule (ALCAM, CD166) and Syntaxin-4. Downregulation of each of these proteins was independently confirmed by immunoblotting with specific antibodies. We further demonstrate that ALCAM is a bona fide target of both K5 and the myxomavirus homolog M153R. Upon exiting the endoplasmic reticulum, ALCAM is ubiquitinated in the presence of wild-type, but not RING-deficient or acidic motif-deficient, K5, and is targeted for lysosomal degradation via the multivesicular body pathway. Since ALCAM is the ligand for CD6, a member of the immunological synapse of T cells, its removal by viral immune modulators implies a role for CD6 in the recognition of pathogens by T cells. The unbiased global proteome analysis therefore revealed novel immunomodulatory functions of pathogen proteins.
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Affiliation(s)
- Eric Bartee
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Ashley McCormack
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Klaus Früh
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
- * To whom correspondence should be addressed. E-mail:
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47
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Ohmura-Hoshino M, Goto E, Matsuki Y, Aoki M, Mito M, Uematsu M, Hotta H, Ishido S. A novel family of membrane-bound E3 ubiquitin ligases. J Biochem 2006; 140:147-54. [PMID: 16954532 DOI: 10.1093/jb/mvj160] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A novel E3 ubiquitin ligase family that consists of viral E3 ubiquitin ligases (E3s) and their mammalian homologues was recently discovered. These novel E3s are membrane-bound molecules that share the secondary structure and catalytic domain for E3 activity. All family members have two transmembrane regions at the center and a RING-CH domain at the amino terminus. Forced expression of these novel E3s has been shown to reduce the surface expression of various membrane proteins through ubiquitination of target molecules. Initial examples of viral E3s were identified in Kaposi's sarcoma associated herpesvirus (KSHV) and murine gamma-herpesvirus 68 (MHV-68) and have been designated as modulator of immune recognition (MIR) 1, 2 and mK3, respectively. MIR 1, 2 and mK3 are able to down-regulate MHC class I molecule expression, and mK3 is required to establish an effective latent viral infection in vivo. The first characterized mammalian homologue to MIR 1, 2 and mK3 is c-MIR/MARCH VIII. Forced expression of c-MIR/MARCH VIII down-regulates B7-2, a co-stimulatory molecule important for antigen presentation. Subsequently, several mammalian molecules related to c-MIR/MARCH VIII have been characterized and named as membrane associated RING-CH (MARCH) family. However, the precise physiological function of MARCH family members remains as yet unknown.
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Affiliation(s)
- Mari Ohmura-Hoshino
- Laboratory for Infectious Immunity, RIKEN Research Center for Allergy and Immunology 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045
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48
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Sedger LM, Osvath SR, Xu XM, Li G, Chan FKM, Barrett JW, McFadden G. Poxvirus tumor necrosis factor receptor (TNFR)-like T2 proteins contain a conserved preligand assembly domain that inhibits cellular TNFR1-induced cell death. J Virol 2006; 80:9300-9. [PMID: 16940541 PMCID: PMC1563942 DOI: 10.1128/jvi.02449-05] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The poxvirus tumor necrosis factor receptor (TNFR) homologue T2 has immunomodulatory properties; secreted myxoma virus T2 (M-T2) protein binds and inhibits rabbit TNF-alpha, while intracellular M-T2 blocks virus-induced lymphocyte apoptosis. Here, we define the antiapoptotic function as inhibition of TNFR-mediated death via a highly conserved viral preligand assembly domain (vPLAD). Jurkat cell lines constitutively expressing M-T2 were generated and shown to be resistant to UV irradiation-, etoposide-, and cycloheximide-induced death. These cells were also resistant to human TNF-alpha, but M-T2 expression did not alter surface expression levels of TNFRs. Previous studies indicated that T2's antiapoptotic function was conferred by the N-terminal region of the protein, and further examination of this region revealed a highly conserved N-terminal vPLAD, which is present in all poxvirus T2-like molecules. In cellular TNFRs and TNF-alpha-related apoptosis-inducing ligand (TRAIL) receptors (TRAILRs), PLAD controls receptor signaling competency prior to ligand binding. Here, we show that M-T2 potently inhibits TNFR1-induced death in a manner requiring the M-T2 vPLAD. Furthermore, we demonstrate that M-T2 physically associates with and colocalizes with human TNFRs but does not prevent human TNF-alpha binding to cellular receptors. Thus, M-T2 vPLAD is a species-nonspecific dominant-negative inhibitor of cellular TNFR1 function. Given that the PLAD is conserved in all known poxvirus T2-like molecules, we predict that it plays an important function in each of these proteins. Moreover, that the vPLAD confers an important antiapoptotic function confirms this domain as a potential target in the development of the next generation of TNF-alpha/TNFR therapeutics.
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Affiliation(s)
- Lisa M Sedger
- Westmead Millennium Institute, Westmead, NSW 2145, Australia.
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49
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Abstract
The cellular biological function of the ubiquitin-proteasome pathway as a major intracellular protein degradation pathway, and as an important modulator for the regulation of many fundamental cellular processes has been greatly appreciated over the last decade. The critical role of the ubiquitin-proteasome pathway in viral pathogenesis has become increasingly apparent. Many viruses have been reported to evolve different strategies to utilize the ubiquitin-proteasome pathway for their own benefits. Here, we review the general background and function of the ubiquitin-proteasome pathway, summarize our current understanding of how viruses use this pathway to target cellular proteins, and finally, discuss the roles of this pathway in enteroviral infection, and the potential therapeutic application of proteasome inhibition in myocarditis.
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Affiliation(s)
- Guang Gao
- Department of Pathology and Laboratory Medicine, The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia-St Paul's Hospital, Vancouver, Canada
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50
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Ohmura-Hoshino M, Matsuki Y, Aoki M, Goto E, Mito M, Uematsu M, Kakiuchi T, Hotta H, Ishido S. Inhibition of MHC Class II Expression and Immune Responses by c-MIR. THE JOURNAL OF IMMUNOLOGY 2006; 177:341-54. [PMID: 16785530 DOI: 10.4049/jimmunol.177.1.341] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We previously reported a novel E3 ubiquitin ligase (E3), designated as c-MIR, which targets B7-2 to lysosomal degradation and down-regulates the B7-2 surface expression through ubiquitination of its cytoplasmic tail. B7-2 is well known as a costimulatory molecule for Ag presentation, suggesting that the manipulation of c-MIR expression modulates immune responses in vivo. To examine this hypothesis, we generated genetically modified mice in which c-MIR was expressed under an invariant chain (Ii) promoter. Dendritic cells derived from genetically engineered mice showed low ability to present Ags. In addition, these mice showed resistance to the onset of experimental autoimmune encephalomyelitis and an impaired development of CD4 T cells in the thymus and the periphery. These findings led us to conclude that MHC class II (MHC II) is an additional target for c-MIR. Indeed, forced expression of c-MIR in several B cell lines down-regulated the surface expression of MHC II, and down-regulation was found to depend on the presence of a single lysine residue in the cytoplasmic tail of the I-A beta-chain. In a reconstitution system using 293T cells, we found that the lysine residue at position 225 in the I-A beta-chain was ubiquitinated by c-MIR. To our knowledge, c-MIR is the first example of an E3 that is capable of inhibiting MHC II expression. Our findings suggest that c-MIR might potently regulate immune responses in vivo.
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Affiliation(s)
- Mari Ohmura-Hoshino
- Laboratory for Infectious Immunity, The Institute of Physical and Chemical Research (RIKEN), Research Center for Allergy and Immunology, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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