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Identification of Marek's disease virus pUL56 homologue and analysis of critical amino acid stretches indispensable for its intracellular localization. Virus Res 2022; 313:198741. [PMID: 35271885 DOI: 10.1016/j.virusres.2022.198741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/02/2022] [Accepted: 03/06/2022] [Indexed: 11/22/2022]
Abstract
Marek's disease virus (MDV) is considered a unique member of the Alphaherpesvirinae subfamily that induces rapid onset of T cell lymphoma in chickens. Compared with other conserved UL56 gene homologues of herpesviruses, little is known about the roles of MDV UL56 gene, while recent studies of mammalian herpesvirus pUL56 proteins have revealed their involvement in promoting ubiquitination of the Nedd4 (neural precursor cell expressed developmentally down-regulated protein 4) -like E3 ubiquitin ligases for proteasomal degradation and in modulating host immune responses. To determine the expression kinetics of UL56 gene products, chicken embryo fibroblasts were infected with very virulent or attenuated MDV strain and analyzed by quantitative PCR and Western blotting. During the time course of infection, the levels of UL56 mRNA transcripts increased consistently. At the translational level, the pUL56 protein encoded by UL56 gene was expressed in the size of 32 kDa, which emerged as early as 12 h post-infection (hpi) but otherwise began to wane at 72 hpi thereafter. With the treatment of viral DNA synthesis inhibitors, the pUL56 expression was significantly reduced, featuring the dynamics of a late (γ)-gene product. By confocal imaging, pUL56 was found to reside in the Golgi compartment. Both the L-domain motifs and the C-terminal tail-anchored transmembrane were essential for its intracellular localization. Noticeably, pUL56 co-localized with a truncated mutant of the chicken Nedd4-like family protein harboring only the WW domains; however, co-immunoprecipitation assay established no direct interaction between them, and the ectopic expression of pUL56 did not alter the abundance of endogenous Nedd4-like protein. Overall, the present study provides a caveat that the pUL56 homologues of different herpesviruses with structural similarities might vary in expression patterns and probably in functional consequences. For this reason, further investigation should be encouraged to focus on the potential association between UL56 gene and MDV pathogenesis in the context of engineered viral mutants.
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2
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Laval K, Poelaert KCK, Van Cleemput J, Zhao J, Vandekerckhove AP, Gryspeerdt AC, Garré B, van der Meulen K, Baghi HB, Dubale HN, Zarak I, Van Crombrugge E, Nauwynck HJ. The Pathogenesis and Immune Evasive Mechanisms of Equine Herpesvirus Type 1. Front Microbiol 2021; 12:662686. [PMID: 33746936 PMCID: PMC7970122 DOI: 10.3389/fmicb.2021.662686] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 02/15/2021] [Indexed: 12/11/2022] Open
Abstract
Equine herpesvirus type 1 (EHV-1) is an alphaherpesvirus related to pseudorabies virus (PRV) and varicella-zoster virus (VZV). This virus is one of the major pathogens affecting horses worldwide. EHV-1 is responsible for respiratory disorders, abortion, neonatal foal death and equine herpes myeloencephalopathy (EHM). Over the last decade, EHV-1 has received growing attention due to the frequent outbreaks of abortions and/or EHM causing serious economical losses to the horse industry worldwide. To date, there are no effective antiviral drugs and current vaccines do not provide full protection against EHV-1-associated diseases. Therefore, there is an urgent need to gain a better understanding of the pathogenesis of EHV-1 in order to develop effective therapies. The main objective of this review is to provide state-of-the-art information on the pathogenesis of EHV-1. We also highlight recent findings on EHV-1 immune evasive strategies at the level of the upper respiratory tract, blood circulation and endothelium of target organs allowing the virus to disseminate undetected in the host. Finally, we discuss novel approaches for drug development based on our current knowledge of the pathogenesis of EHV-1.
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Affiliation(s)
- Kathlyn Laval
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Katrien C K Poelaert
- Division of Virology, Department Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Jolien Van Cleemput
- HIV Cure Research Center, Department of Internal Medicine and Pediatrics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Jing Zhao
- Shenzhen International Institute for Biomedical Research, Shenzhen, China
| | | | | | | | | | - Hossein B Baghi
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Haileleul N Dubale
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| | - Ines Zarak
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Eline Van Crombrugge
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Hans J Nauwynck
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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3
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Evasion of the Cell-Mediated Immune Response by Alphaherpesviruses. Viruses 2020; 12:v12121354. [PMID: 33256093 PMCID: PMC7761393 DOI: 10.3390/v12121354] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 11/25/2020] [Accepted: 11/25/2020] [Indexed: 12/17/2022] Open
Abstract
Alphaherpesviruses cause various diseases and establish life-long latent infections in humans and animals. These viruses encode multiple viral proteins and miRNAs to evade the host immune response, including both innate and adaptive immunity. Alphaherpesviruses evolved highly advanced immune evasion strategies to be able to replicate efficiently in vivo and produce latent infections with recurrent outbreaks. This review describes the immune evasion strategies of alphaherpesviruses, especially against cytotoxic host immune responses. Considering these strategies, it is important to evaluate whether the immune evasion mechanisms in cell cultures are applicable to viral propagation and pathogenicity in vivo. This review focuses on cytotoxic T lymphocytes (CTLs), natural killer cells (NK cells), and natural killer T cells (NKT cells), which are representative immune cells that directly damage virus-infected cells. Since these immune cells recognize the ligands expressed on their target cells via specific activating and/or inhibitory receptors, alphaherpesviruses make several ligands that may be targets for immune evasion. In addition, alphaherpesviruses suppress the infiltration of CTLs by downregulating the expression of chemokines at infection sites in vivo. Elucidation of the alphaherpesvirus immune evasion mechanisms is essential for the development of new antiviral therapies and vaccines.
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Pavulraj S, Kamel M, Stephanowitz H, Liu F, Plendl J, Osterrieder N, Azab W. Equine Herpesvirus Type 1 Modulates Cytokine and Chemokine Profiles of Mononuclear Cells for Efficient Dissemination to Target Organs. Viruses 2020; 12:v12090999. [PMID: 32911663 PMCID: PMC7551999 DOI: 10.3390/v12090999] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/31/2020] [Accepted: 09/05/2020] [Indexed: 12/13/2022] Open
Abstract
Equine herpesvirus type 1 (EHV-1) causes encephalomyelopathy and abortion, for which cell-associated viremia and subsequent virus transfer to and replication in endothelial cells (EC) are responsible and prerequisites. Viral and cellular molecules responsible for efficient cell-to-cell spread of EHV-1 between peripheral blood mononuclear cells (PBMC) and EC remain unclear. We have generated EHV-1 mutants lacking ORF1, ORF2, and ORF17 genes, either individually or in combination. Mutant viruses were analyzed for their replication properties in cultured equine dermal cells, PBMC infection efficiency, virus-induced changes in the PBMC proteome, and cytokine and chemokine expression profiles. ORF1, ORF2, and ORF17 are not essential for virus replication, but ORF17 deletion resulted in a significant reduction in plaque size. Deletion of ORF2 and ORF17 gene significantly reduced cell-to-cell virus transfer from virus-infected PBMC to EC. EHV-1 infection of PBMC resulted in upregulation of several pathways such as Ras signaling, oxidative phosphorylation, platelet activation and leukocyte transendothelial migration. In contrast, chemokine signaling, RNA degradation and apoptotic pathways were downregulated. Deletion of ORF1, ORF2 and ORF17 modulated chemokine signaling and MAPK pathways in infected PBMC, which may explain the impairment of virus spread between PBMC and EC. The proteomic results were further confirmed by chemokine assays, which showed that virus infection dramatically reduced the cytokine/chemokine release in infected PBMC. This study uncovers cellular proteins and pathways influenced by EHV-1 after PBMC infection and provide an important resource for EHV-1 pathogenesis. EHV-1-immunomodulatory genes could be potential targets for the development of live attenuated vaccines or therapeutics against virus infection.
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Affiliation(s)
- Selvaraj Pavulraj
- Institut für Virologie, Robert von Ostertag-Haus, Zentrum für Infektionsmedizin, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany; (S.P.); (M.K.); (N.O.)
| | - Mohamed Kamel
- Institut für Virologie, Robert von Ostertag-Haus, Zentrum für Infektionsmedizin, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany; (S.P.); (M.K.); (N.O.)
- Department of Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Cairo University, 12211 Cairo, Egypt
| | - Heike Stephanowitz
- Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Rössle-Str. 10, 13125 Berlin, Germany; (H.S.); (F.L.)
| | - Fan Liu
- Leibniz Institute of Molecular Pharmacology (FMP Berlin), Robert-Rössle-Str. 10, 13125 Berlin, Germany; (H.S.); (F.L.)
| | - Johanna Plendl
- Institut für Veterinäranatomie, Freie Universität Berlin, Koserstraße 20, 14195 Berlin, Germany;
| | - Nikolaus Osterrieder
- Institut für Virologie, Robert von Ostertag-Haus, Zentrum für Infektionsmedizin, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany; (S.P.); (M.K.); (N.O.)
| | - Walid Azab
- Institut für Virologie, Robert von Ostertag-Haus, Zentrum für Infektionsmedizin, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany; (S.P.); (M.K.); (N.O.)
- Correspondence: ; Tel.: +49-30-838-50087
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5
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Zhao H, Wang S, Liu C, Han J, Tang J, Zhou L, Ge X, Guo X, Yang H. The pUL56 of pseudorabies virus variant induces downregulation of swine leukocyte antigen class I molecules through the lysosome pathway. Virus Res 2018; 251:56-67. [PMID: 29634995 DOI: 10.1016/j.virusres.2018.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 11/17/2022]
Abstract
Pseudorabies virus (PRV) is the causative agent of pseudorabies (PR) which causes large economic losses for Chinese swine industry since breaking out in late 2011. As a member of herpesviruses, PRV is able to escape the host immune elimination and establish latency, resulting in persistent infection. Here, we report that a currently prevalent Chinese PRV variant down-regulated swine leukocyte antigen class I (SLA-I) molecules on the surface of PK-15 cells and targeted them for degradation through lysosome pathway. Viral pUL56 protein, independent of other viral proteins, was associated with this function by inducing degradation of cellular SLA-I heavy chain (HC) in a manner that was dependent on the lysosome machinery. In addition, pUL56 interacted with SLA-I HC and increased its ubiquitination. Further studies demonstrated that the late domains (PPXY motifs) of pUL56 were required for the ubiquitination and degradation of SLA-I HC by pUL56. Together, our findings reveal the mechanisms by which PRV interferes with cytotoxic T lymphocyte (CTL) responses and provide novel insights into the roles of PRV pUL56.
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Affiliation(s)
- Hongyuan Zhao
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Shujie Wang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Chu Liu
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Jun Han
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Jun Tang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Lei Zhou
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Xinna Ge
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Xin Guo
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China.
| | - Hanchun Yang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
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6
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Bach SV, Hegde AN. The proteasome and epigenetics: zooming in on histone modifications. Biomol Concepts 2017; 7:215-27. [PMID: 27522625 DOI: 10.1515/bmc-2016-0016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/12/2016] [Indexed: 12/11/2022] Open
Abstract
The proteasome is a structural complex of many proteins that degrades substrates marked by covalent linkage to ubiquitin. Many years of research has shown a role for ubiquitin-proteasome-mediated proteolysis in synaptic plasticity and memory mainly in degrading synaptic, cytoplasmic and nuclear proteins. Recent work indicates that the proteasome has wider proteolytic and non-proteolytic roles in processes such as histone modifications that affect synaptic plasticity and memory. In this review, we assess the evidence gathered from neuronal as well as non-neuronal cell types regarding the function of the proteasome in positive or negative regulation of posttranslational modifications of histones, such as acetylation, methylation and ubiquitination. We discuss the critical roles of the proteasome in clearing excess histone proteins in various cellular contexts and the possible non-proteolytic functions in regulating transcription of target genes. In addition, we summarize the current literature on diverse chromatin-remodeling machineries, such as histone acetyltransferases, deacetylates, methyltransferases and demethylases, as targets for proteasomal degradation across experimental models. Lastly, we provide a perspective on how proteasomal regulation of histone modifications may modulate synaptic plasticity in the nervous system.
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7
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Schuren AB, Costa AI, Wiertz EJ. Recent advances in viral evasion of the MHC Class I processing pathway. Curr Opin Immunol 2016; 40:43-50. [PMID: 27065088 DOI: 10.1016/j.coi.2016.02.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 02/12/2016] [Accepted: 02/22/2016] [Indexed: 11/17/2022]
Abstract
T-cell mediated adaptive immunity against viruses relies on recognition of virus-derived peptides by CD4(+) and CD8(+) T cells. Detection of pathogen-derived peptide-MHC-I complexes triggers CD8(+) T cells to eliminate the infected cells. Viruses have evolved several mechanisms to avoid recognition, many of which target the MHC-I antigen-processing pathway. While many immune evasion strategies have been described in the context of herpesvirus infections, it is becoming clear that this 'disguise' ability is more widespread. Here, we address recent findings in viral evasion of the MHC-I antigen presentation pathway and the impact on CD8(+) T cell responses.
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Affiliation(s)
- Anouk Bc Schuren
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ana I Costa
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Emmanuel Jhj Wiertz
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
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8
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Claessen C, De Lange V, Huang T, Ma G, Osterrieder N, Favoreel H, Van de Walle GR. Equine herpesvirus type 1 (EHV1) induces alterations in the immunophenotypic profile of equine monocyte-derived dendritic cells. Vet J 2016; 210:85-8. [PMID: 26920348 DOI: 10.1016/j.tvjl.2015.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 12/11/2015] [Accepted: 12/14/2015] [Indexed: 10/22/2022]
Abstract
Equine herpesvirus 1 (EHV1) is an α-herpesvirus that can infect a variety of different cells in vitro and in vivo, including dendritic cells (DC) which are essential in the immune response against EHV1. Infection of equine monocyte-derived DC (MDDC) with EHV1 induced down-regulation of major histocompatibility complex I (MHCI), CD83, CD86, CD206, CD29 and CD172a, but not of CD11a/CD18 and MHCII. This down-regulation was not mediated by the virion host-shutoff (VHS) protein or pUL49.5. Interestingly, down-regulation of CD83 and CD86 was in part mediated by pUL56. Taken together, these data indicate that EHV1 employs different and still unresolved mechanisms to induce down-regulation of several functionally important cell surface proteins on equine DC.
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Affiliation(s)
- Christophe Claessen
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
| | - Valérie De Lange
- Department of Obstetrics, Reproduction and Herd Health, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
| | - Teng Huang
- Institut für Virologie, Freie Universität Berlin, 14163 Berlin, Germany
| | - Guanggang Ma
- Institut für Virologie, Freie Universität Berlin, 14163 Berlin, Germany
| | | | - Herman Favoreel
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
| | - Gerlinde R Van de Walle
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium; Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850, USA.
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The pseudorabies virus protein, pUL56, enhances virus dissemination and virulence but is dispensable for axonal transport. Virology 2015; 488:179-86. [PMID: 26655235 DOI: 10.1016/j.virol.2015.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/11/2015] [Accepted: 11/15/2015] [Indexed: 11/23/2022]
Abstract
Neurotropic herpesviruses exit the peripheral nervous system and return to exposed body surfaces following reactivation from latency. The pUS9 protein is a critical viral effector of the anterograde axonal transport that underlies this process. We recently reported that while pUS9 increases the frequency of sorting of newly assembled pseudorabies virus particles to axons from the neural soma during egress, subsequent axonal transport of individual virus particles occurs with wild-type kinetics in the absence of the protein. Here, we examine the role of a related pseudorabies virus protein, pUL56, during neuronal infection. The findings indicate that pUL56 is a virulence factor that supports virus dissemination in vivo, yet along with pUS9, is dispensable for axonal transport.
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10
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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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Binding of alphaherpesvirus glycoprotein H to surface α4β1-integrins activates calcium-signaling pathways and induces phosphatidylserine exposure on the plasma membrane. mBio 2015; 6:e01552-15. [PMID: 26489864 PMCID: PMC4620472 DOI: 10.1128/mbio.01552-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Intracellular signaling connected to integrin activation is known to induce cytoplasmic Ca2+ release, which in turn mediates a number of downstream signals. The cellular entry pathways of two closely related alphaherpesviruses, equine herpesviruses 1 and 4 (EHV-1 and EHV-4), are differentially regulated with respect to the requirement of interaction of glycoprotein H (gH) with α4β1-integrins. We show here that binding of EHV-1, but not EHV-4, to target cells resulted in a rapid and significant increase in cytosolic Ca2+ levels. EHV-1 expressing EHV-4 gH (gH4) in lieu of authentic gH1 failed to induce Ca2+ release, while EHV-4 with gH1 triggered significant Ca2+ release. Blocking the interaction between gH1 and α4β1-integrins, inhibiting phospholipase C (PLC) activation, or blocking binding of inositol 1,4,5-triphosphate (IP3) to its receptor on the endoplasmic reticulum (ER) abrogated Ca2+ release. Interestingly, phosphatidylserine (PS) was exposed on the plasma membrane in response to cytosolic calcium increase after EHV-1 binding through a scramblase-dependent mechanism. Inhibition of both Ca2+ release from the ER and scramblase activation blocked PS scrambling and redirected virus entry to the endocytic pathway, indicating that PS may play a role in facilitating virus entry directly at the plasma membrane. Herpesviruses are a large family of enveloped viruses that infect a wide range of hosts, causing a variety of diseases. These viruses have developed a number of strategies for successful entry into different cell types. We and others have shown that alphaherpesviruses, including EHV-1 and herpes simplex virus 1 (HSV-1), can route their entry pathway and do so by manipulation of cell signaling cascades to ensure viral genome delivery to nuclei. We show here that the interaction between EHV-1 gH and cellular α4β1-integrins is necessary to induce emptying of ER calcium stores, which induces phosphatidylserine exposure on the plasma membrane through a scramblase-dependent mechanism. This change in lipid asymmetry facilitates virus entry and might help fusion of the viral envelope at the plasma membrane. These findings will help to advance our understanding of herpesvirus entry mechanism and may facilitate the development of novel drugs that can be implemented for prevention of infection and disease.
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12
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Bergmann T, Moore C, Sidney J, Miller D, Tallmadge R, Harman RM, Oseroff C, Wriston A, Shabanowitz J, Hunt DF, Osterrieder N, Peters B, Antczak DF, Sette A. The common equine class I molecule Eqca-1*00101 (ELA-A3.1) is characterized by narrow peptide binding and T cell epitope repertoires. Immunogenetics 2015; 67:675-89. [PMID: 26399241 DOI: 10.1007/s00251-015-0872-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 09/14/2015] [Indexed: 11/29/2022]
Abstract
Here we describe a detailed quantitative peptide-binding motif for the common equine leukocyte antigen (ELA) class I allele Eqca-1*00101, present in roughly 25 % of Thoroughbred horses. We determined a preliminary binding motif by sequencing endogenously bound ligands. Subsequently, a positional scanning combinatorial library (PSCL) was used to further characterize binding specificity and derive a quantitative motif involving aspartic acid in position 2 and hydrophobic residues at the C-terminus. Using this motif, we selected and tested 9- and 10-mer peptides derived from the equine herpesvirus type 1 (EHV-1) proteome for their capacity to bind Eqca-1*00101. PSCL predictions were very efficient, with an receiver operating characteristic (ROC) curve performance of 0.877, and 87 peptides derived from 40 different EHV-1 proteins were identified with affinities of 500 nM or higher. Quantitative analysis revealed that Eqca-1*00101 has a narrow peptide-binding repertoire, in comparison to those of most human, non-human primate, and mouse class I alleles. Peripheral blood mononuclear cells from six EHV-1-infected, or vaccinated but uninfected, Eqca-1*00101-positive horses were used in IFN-γ enzyme-linked immunospot (ELISPOT) assays. When we screened the 87 Eqca-1*00101-binding peptides for T cell reactivity, only one Eqca-1*00101 epitope, derived from the intermediate-early protein ICP4, was identified. Thus, despite its common occurrence in several horse breeds, Eqca-1*00101 is associated with a narrow binding repertoire and a similarly narrow T cell response to an important equine viral pathogen. Intriguingly, these features are shared with other human and macaque major histocompatibility complex (MHC) molecules with a similar specificity for D in position 2 or 3 in their main anchor motif.
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Affiliation(s)
- Tobias Bergmann
- Institut für Virologie, Freie Universtiät Berlin, 14163, Berlin, Germany
| | - Carrie Moore
- Department of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - John Sidney
- Department of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Donald Miller
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Rebecca Tallmadge
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Rebecca M Harman
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Carla Oseroff
- Department of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Amanda Wriston
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA
| | - Jeffrey Shabanowitz
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA
| | - Donald F Hunt
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA.,Department of Pathology, University of Virginia, Charlottesville, VA, 22904, USA
| | | | - Bjoern Peters
- Department of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Douglas F Antczak
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Alessandro Sette
- Department of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA.
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Huang T, Osterrieder N. The herpesvirus stealth program. Oncotarget 2015; 6:21761-2. [PMID: 26335280 PMCID: PMC4673107 DOI: 10.18632/oncotarget.5261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Equine Herpesvirus 1 Multiply Inserted Transmembrane Protein pUL43 Cooperates with pUL56 in Downregulation of Cell Surface Major Histocompatibility Complex Class I. J Virol 2015; 89:6251-63. [PMID: 25833055 DOI: 10.1128/jvi.00032-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/27/2015] [Indexed: 01/09/2023] Open
Abstract
UNLABELLED Herpesviruses have evolved an array of strategies to counteract antigen presentation by major histocompatibility complex class I (MHC-I). Previously, we identified pUL56 of equine herpesvirus 1 (EHV-1) as one major determinant of the downregulation of cell surface MHC-I (G. Ma, S. Feineis, N. Osterrieder, and G. R. Van de Walle, J. Virol. 86:3554-3563, 2012, http://dx.doi.org/10.1128/JVI.06994-11; T. Huang, M. J. Lehmann, A. Said, G. Ma, and N. Osterrieder, J. Virol. 88:12802-12815, 2014, http://dx.doi.org/10.1128/JVI.02079-14). Since pUL56 was able to exert its function only in the context of virus infection, we hypothesized that pUL56 cooperates with another viral protein. Here, we generated and screened a series of EHV-1 single-gene deletion mutants and found that the pUL43 orthologue was required for downregulation of cell surface MHC-I expression at the same time of infection as when pUL56 exerts its function. We demonstrate that the absence of pUL43 was not deleterious to virus growth and that expression of pUL43 was detectable from 2 h postinfection (p.i.) but decreased after 8 h p.i. due to lysosomal degradation. pUL43 localized within Golgi vesicles and required a unique hydrophilic N-terminal domain to function properly. Finally, coexpression of pUL43 and pUL56 in transfected cells reduced the cell surface expression of MHC-I. This process was dependent on PPxY motifs present in pUL56, suggesting that late domains are required for pUL43- and pUL56-dependent sorting of MHC class I for lysosomal degradation. IMPORTANCE We describe here that the poorly characterized herpesviral protein pUL43 is involved in downregulation of cell surface MHC-I. pUL43 is an early protein and degraded in lysosomes. pUL43 resides in the Golgi vesicles and needs an intact N terminus to induce MHC-I downregulation in infected cells. Importantly, pUL43 and pUL56 cooperate to reduce MHC-I expression on the surface of transfected cells. Our results suggest a model for MHC-I downregulation in which late domains in pUL56 are required for the rerouting of vesicles containing MHC-I, pUL56, and pUL43 to the lysosomal compartment.
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Equid herpesvirus 1 (EHV1) infection of equine mesenchymal stem cells induces a pUL56-dependent downregulation of select cell surface markers. Vet Microbiol 2014; 176:32-9. [PMID: 25582614 DOI: 10.1016/j.vetmic.2014.12.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 12/01/2014] [Accepted: 12/02/2014] [Indexed: 01/09/2023]
Abstract
Equid herpesvirus 1 (EHV1) is an ubiquitous alphaherpesvirus that can cause respiratory disease, abortion and central nervous disorders. EHV1 is known to infect a variety of different cell types in vitro, but its tropism for cultured primary equine mesenchymal stem cells (MSC) has never been explored. We report that equine MSC were highly permissive for EHV1 and supported lytic replication of the virus in vitro. Interestingly, we observed that an infection of MSC with EHV1 resulted in a consistent downregulation of cell surface molecules CD29 (β1-integrin), CD105 (endoglin), major histocompatibility complex type I (MHCI) and a variable downregulation of CD172a. In contrast, expression of CD44 and CD90 remained unchanged upon wild type infection. In addition, we found that this selective EHV1-mediated downregulation of cell surface proteins was dependent on the viral protein UL56 (pUL56). So far, pUL56-dependent downregulation during EHV1 infection of equine cells has only been described for MHCI, but our present data indicate that pUL56 may have a broader function in downregulating cell surface proteins. Taken together, our results are the first to show that equine MSC are susceptible for EHV1 and that pUL56 induces downregulation of several cell surface molecules on infected cells. These findings provide a basis for future studies to evaluate the mechanisms underlying for this selective pUL56-induced downregulation and to evaluate the potential role of MSC during EHV1 pathogenesis.
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