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Le-Trilling VTK, Maaßen F, Katschinski B, Hengel H, Trilling M. Deletion of the non-adjacent genes UL148 and UL148D impairs human cytomegalovirus-mediated TNF receptor 2 surface upregulation. Front Immunol 2023; 14:1170300. [PMID: 37600801 PMCID: PMC10437809 DOI: 10.3389/fimmu.2023.1170300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 07/11/2023] [Indexed: 08/22/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a prototypical β-herpesvirus which frequently causes morbidity and mortality in individuals with immature, suppressed, or senescent immunity. HCMV is sensed by various pattern recognition receptors, leading to the secretion of pro-inflammatory cytokines including tumor necrosis factor alpha (TNFα). TNFα binds to two distinct trimeric receptors: TNF receptor (TNFR) 1 and TNFR2, which differ in regard to their expression profiles, affinities for soluble and membrane-bound TNFα, and down-stream signaling pathways. While both TNF receptors engage NFκB signaling, only the nearly ubiquitously expressed TNFR1 exhibits a death domain that mediates TRADD/FADD-dependent caspase activation. Under steady-state conditions, TNFR2 expression is mainly restricted to immune cells where it predominantly submits pro-survival, proliferation-stimulating, and immune-regulatory signals. Based on the observation that HCMV-infected cells show enhanced binding of TNFα, we explored the interplay between HCMV and TNFR2. As expected, uninfected fibroblasts did not show detectable levels of TNFR2 on the surface. Intriguingly, however, HCMV infection increased TNFR2 surface levels of fibroblasts. Using HCMV variants and BACmid-derived clones either harboring or lacking the ULb' region, an association between TNFR2 upregulation and the presence of the ULb' genome region became evident. Applying a comprehensive set of ULb' gene block and single gene deletion mutants, we observed that HCMV mutants in which the non-adjacent genes UL148 or UL148D had been deleted show an impaired ability to upregulate TNFR2, coinciding with an inverse regulation of TACE/ADAM17.
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Affiliation(s)
| | - Fabienne Maaßen
- Institute for Virology, University Hospital Essen, University of Duisburg−Essen, Essen, Germany
| | - Benjamin Katschinski
- Institute for Virology, University Hospital Essen, University of Duisburg−Essen, Essen, Germany
| | - Hartmut Hengel
- Institute of Virology, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Mirko Trilling
- Institute for Virology, University Hospital Essen, University of Duisburg−Essen, Essen, Germany
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Krauter S, Büscher N, Bräuchle E, Ortega Iannazzo S, Penner I, Krämer N, Gogesch P, Thomas S, Kreutz M, Dejung M, Freiwald A, Butter F, Waibler Z, Plachter B. An Attenuated Strain of Human Cytomegalovirus for the Establishment of a Subviral Particle Vaccine. Vaccines (Basel) 2022; 10:vaccines10081326. [PMID: 36016214 PMCID: PMC9413975 DOI: 10.3390/vaccines10081326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/16/2022] Open
Abstract
Human cytomegalovirus (HCMV) infection is associated with severe disease conditions either following congenital transmission of the virus or viral reactivation in immunosuppressed individuals. Consequently, the establishment of a protective vaccine is of high medical need. Several candidates have been tested in preclinical and clinical studies, yet no vaccine has been licensed. Subviral dense bodies (DB) are a promising vaccine candidate. We have recently provided a GMP-compliant protocol for the production of DB, based on a genetically modified version of the HCMV laboratory strain Towne, expressing the pentameric complex of envelope protein gH-gL-pUL128-131 (Towne-UL130rep). In this work, we genetically attenuated Towne-UL130rep by abrogating the expression of the tegument protein pUL25 and by fusing the destabilizing domain ddFKBP to the N-terminus of the IE1- and IE2-proteins of HCMV. The resulting strain, termed TR-VAC, produced high amounts of DB under IE1/IE2 repressive conditions and concomitant supplementation of the viral terminase inhibitor letermovir to the producer cell culture. TR-VAC DB retained the capacity to induce neutralizing antibodies. A complex pattern of host protein induction was observed by mass spectrometry following exposure of primary human monocytes with TR-VAC DB. Human monocyte-derived dendritic cells (DC) moderately increased the expression of activation markers and MHC molecules upon stimulation with TR-VAC DB. In a co-culture with autologous T cells, the TR-VAC DB-stimulated DC induced a robust HCMV-specific T cell-activation and –proliferation. Exposure of donor-derived monocytic cells to DB led to the activation of a rapid innate immune response. This comprehensive data set thus shows that TR-VAC is an optimal attenuated seed virus strain for the production of a DB vaccine to be tested in clinical studies.
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Affiliation(s)
- Steffi Krauter
- Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany
| | - Nicole Büscher
- Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany
| | - Eric Bräuchle
- Division of Immunology, Section 3/1 “Product Testing of Immunological Biomedicines”, Paul-Ehrlich-Institut, D-63225 Langen, Germany
| | - Samira Ortega Iannazzo
- Division of Immunology, Section 3/1 “Product Testing of Immunological Biomedicines”, Paul-Ehrlich-Institut, D-63225 Langen, Germany
| | - Inessa Penner
- Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany
| | - Nadine Krämer
- Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany
| | - Patricia Gogesch
- Division of Immunology, Section 3/1 “Product Testing of Immunological Biomedicines”, Paul-Ehrlich-Institut, D-63225 Langen, Germany
| | - Simone Thomas
- Leibniz Institute for Immunotherapy, Regensburg and Klinik und Poliklinik für Innere Medizin III, Hämatologie und Internistische Onkologie, University Hospital Regensburg, D-93053 Regensburg, Germany
| | - Marina Kreutz
- Leibniz Institute for Immunotherapy, Regensburg and Klinik und Poliklinik für Innere Medizin III, Hämatologie und Internistische Onkologie, University Hospital Regensburg, D-93053 Regensburg, Germany
| | - Mario Dejung
- Proteomics Core Facility, Institute of Molecular Biology, D-55128 Mainz, Germany
| | - Anja Freiwald
- Proteomics Core Facility, Institute of Molecular Biology, D-55128 Mainz, Germany
| | - Falk Butter
- Proteomics Core Facility, Institute of Molecular Biology, D-55128 Mainz, Germany
| | - Zoe Waibler
- Division of Immunology, Section 3/1 “Product Testing of Immunological Biomedicines”, Paul-Ehrlich-Institut, D-63225 Langen, Germany
| | - Bodo Plachter
- Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany
- Correspondence: ; Tel.: +49-6131-179232
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Hong YM, Min SY, Kim D, Kim S, Seo D, Lee KH, Han SH. Human MicroRNAs Attenuate the Expression of Immediate Early Proteins and HCMV Replication during Lytic and Latent Infection in Connection with Enhancement of Phosphorylated RelA/p65 (Serine 536) That Binds to MIEP. Int J Mol Sci 2022; 23:ijms23052769. [PMID: 35269913 PMCID: PMC8911160 DOI: 10.3390/ijms23052769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/24/2022] [Accepted: 02/28/2022] [Indexed: 02/05/2023] Open
Abstract
Attenuating the expression of immediate early (IE) proteins is essential for controlling the lytic replication of human cytomegalovirus (HCMV). The human microRNAs (hsa-miRs), miR-200b-3p and miR-200c-3p, have been identified to bind the 3′-untranslated region (3′-UTR) of the mRNA encoding IE proteins. However, whether hsa-miRs can reduce IE72 expression and HCMV viral load or exhibit a crosstalk with the host cellular signaling machinery, most importantly the NF-κB cascade, has not been evaluated. In this study, argonaute-crosslinking and immunoprecipitation-seq revealed that miR-200b-3p and miR-200c-3p bind the 3′-UTR of UL123, which is a gene that encodes IE72. The binding of these miRNAs to the 3′-UTR of UL123 was verified in transfected cells stably expressing GFP. We used miR-200b-3p/miR-200c-3p mimics to counteract the downregulation of these miRNA after acute HCMV infection. This resulted in reduced IE72/IE86 expression and HCMV VL during lytic infection. We determined that IE72/IE86 alone can inhibit the phosphorylation of RelA/p65 at the Ser536 residue and that p-Ser536 RelA/p65 binds to the major IE promoter/enhancer (MIEP). The upregulation of miR-200b-3p and miR-200c-3p resulted in the phosphorylation of RelA/p65 at Ser536 through the downregulation of IE, and the binding of the resultant p-Ser536 RelA/p65 to MIEP resulted in a decreased production of pro-inflammatory cytokines. Overall, miR-200b-3p and miR-200c-3p—together with p-Ser536 RelA/p65—can prevent lytic HCMV replication during acute and latent infection
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Affiliation(s)
- Yeon-Mi Hong
- Division of Infectious Disease, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 06273, Korea; (Y.-M.H.); (S.Y.M.); (D.K.); (S.K.); (K.H.L.)
| | - Seo Yeon Min
- Division of Infectious Disease, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 06273, Korea; (Y.-M.H.); (S.Y.M.); (D.K.); (S.K.); (K.H.L.)
| | - Dayeong Kim
- Division of Infectious Disease, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 06273, Korea; (Y.-M.H.); (S.Y.M.); (D.K.); (S.K.); (K.H.L.)
| | - Subin Kim
- Division of Infectious Disease, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 06273, Korea; (Y.-M.H.); (S.Y.M.); (D.K.); (S.K.); (K.H.L.)
| | - Daekwan Seo
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 06273, Korea;
| | - Kyoung Hwa Lee
- Division of Infectious Disease, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 06273, Korea; (Y.-M.H.); (S.Y.M.); (D.K.); (S.K.); (K.H.L.)
| | - Sang Hoon Han
- Division of Infectious Disease, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 06273, Korea; (Y.-M.H.); (S.Y.M.); (D.K.); (S.K.); (K.H.L.)
- Correspondence: ; Tel.: +82-2-2019-3319; Fax: +82-2-3463-3882
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SAMHD1 … and Viral Ways around It. Viruses 2021; 13:v13030395. [PMID: 33801276 PMCID: PMC7999308 DOI: 10.3390/v13030395] [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] [Received: 02/12/2021] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/19/2022] Open
Abstract
The SAM and HD domain-containing protein 1 (SAMHD1) is a dNTP triphosphohydrolase that plays a crucial role for a variety of different cellular functions. Besides balancing intracellular dNTP concentrations, facilitating DNA damage repair, and dampening excessive immune responses, SAMHD1 has been shown to act as a major restriction factor against various virus species. In addition to its well-described activity against retroviruses such as HIV-1, SAMHD1 has been identified to reduce the infectivity of different DNA viruses such as the herpesviruses CMV and EBV, the poxvirus VACV, or the hepadnavirus HBV. While some viruses are efficiently restricted by SAMHD1, others have developed evasion mechanisms that antagonize the antiviral activity of SAMHD1. Within this review, we summarize the different cellular functions of SAMHD1 and highlight the countermeasures viruses have evolved to neutralize the restriction factor SAMHD1.
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The NFKB1 Promoter Polymorphism (-94ins/delATTG) Is Associated with Susceptibility to Cytomegalovirus Infection after Kidney Transplantation and Should Have Implications on CMV Prophylaxis Regimens. Cells 2021; 10:cells10020380. [PMID: 33673169 PMCID: PMC7918124 DOI: 10.3390/cells10020380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 11/16/2022] Open
Abstract
Infections with cytomegalovirus (CMV) are one of the most frequent opportunistic infections in kidney transplant recipients. Current risk-adapted CMV chemoprophylaxis regimens are based almost solely on the donor and recipient CMV serostatus. Of note, the NFKB1 -94ins/delATTG promoter polymorphism was recently associated with a higher risk of CMV infection. Since single genetic association studies suffer from poor reliability for drawing therapeutic implications, we performed this confirmatory study and included 256 kidney transplant recipients from 2007 to 2014 in this retrospective study. Patients were genotyped for the -94ins/delATTG NFKB1 promoter polymorphism and followed up for 12 months. The incidence of CMV infection within 12 months after kidney transplantation was 37.5% (33/88) for the ins/ins, 21.5% (28/130) for the ins/del, and 23.7% (9/38) for the del/del genotypes (p = 0.023). Moreover, we evaluated the time of CMV infection onset. Ins/ins carriers had primarily late-onset CMV infection (median 194 days; interquartile range (IQR) 117–267 days) compared with heterozygous (ins/del; median 158 days; IQR 82–195 days) and homozygous deletion allele carriers (del/del; median 95 days; 84–123 days). Multivariate-restricted Cox regression model confirmed the ins/ins genotype to be an independent risk factor for the development of late-onset CMV infections. These findings should have an impact on post-kidney transplantation CMV chemoprophylaxis regimens.
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Kim ET, Roche KL, Kulej K, Spruce LA, Seeholzer SH, Coen DM, Diaz-Griffero F, Murphy EA, Weitzman MD. SAMHD1 Modulates Early Steps during Human Cytomegalovirus Infection by Limiting NF-κB Activation. Cell Rep 2020; 28:434-448.e6. [PMID: 31291579 DOI: 10.1016/j.celrep.2019.06.027] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 03/22/2019] [Accepted: 06/05/2019] [Indexed: 12/14/2022] Open
Abstract
Cellular SAMHD1 inhibits replication of many viruses by limiting intracellular deoxynucleoside triphosphate (dNTP) pools. We investigate the influence of SAMHD1 on human cytomegalovirus (HCMV). During HCMV infection, we observe SAMHD1 induction, accompanied by phosphorylation via viral kinase UL97. SAMHD1 depletion increases HCMV replication in permissive fibroblasts and conditionally permissive myeloid cells. We show this is due to enhanced gene expression from the major immediate-early (MIE) promoter and is independent of dNTP levels. SAMHD1 suppresses innate immune responses by inhibiting nuclear factor κB (NF-κB) activation. We show that SAMHD1 regulates the HCMV MIE promoter through NF-κB activation. Chromatin immunoprecipitation reveals increased RELA and RNA polymerase II on the HCMV MIE promoter in the absence of SAMHD1. Our studies reveal a mechanism of HCMV virus restriction by SAMHD1 and show how SAMHD1 deficiency activates an innate immune pathway that paradoxically results in increased viral replication through transcriptional activation of the HCMV MIE gene promoter.
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Affiliation(s)
- Eui Tae Kim
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kathryn L Roche
- Department of Translational Medicine, Baruch S. Blumberg Research Institute, Doylestown, PA 18902, USA; Evrys Bio, Pennsylvania Biotechnology Center, Doylestown, PA 18902, USA
| | - Katarzyna Kulej
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Lynn A Spruce
- Protein and Proteomics Core, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Steven H Seeholzer
- Protein and Proteomics Core, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Donald M Coen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Felipe Diaz-Griffero
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Eain A Murphy
- Department of Translational Medicine, Baruch S. Blumberg Research Institute, Doylestown, PA 18902, USA; Evrys Bio, Pennsylvania Biotechnology Center, Doylestown, PA 18902, USA
| | - Matthew D Weitzman
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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Identification of a novel signaling complex containing host chemokine receptor CXCR4, Interleukin-10 receptor, and human cytomegalovirus US27. Virology 2020; 548:49-58. [PMID: 32838946 DOI: 10.1016/j.virol.2020.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/27/2020] [Accepted: 06/10/2020] [Indexed: 11/21/2022]
Abstract
Human cytomegalovirus (HCMV) is a widespread herpesvirus that establishes latency in myeloid cells and persists by manipulating immune signaling. Chemokine receptor CXCR4 and its ligand CXCL12 regulate movement of myeloid progenitors into bone marrow and out into peripheral tissues. HCMV amplifies CXCL12-CXCR4 signaling through viral chemokine receptor US27 and cmvIL-10, a viral cytokine that binds the cellular IL-10 receptor (IL-10R), but precisely how these viral proteins influence CXCR4 is unknown. We used the proximity ligation assay (PLA) to examine association of CXCR4, IL-10R, and US27 in both transfected and HCMV-infected cells. CXCR4 and IL-10R colocalized to discrete clusters, and treatment with CXCL12 and cmvIL-10 dramatically increased receptor clustering and calcium flux. US27 was associated with CXCR4 and IL-10R in PLA clusters and further enhanced cluster formation and calcium signaling. These results indicate that CXCR4, IL-10R, and US27 form a novel virus-host signaling complex that enhances CXCL12 signaling during HCMV infection.
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Human Cytomegalovirus Glycoprotein-Initiated Signaling Mediates the Aberrant Activation of Akt. J Virol 2020; 94:JVI.00167-20. [PMID: 32493823 DOI: 10.1128/jvi.00167-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/27/2020] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a major cause of morbidity and mortality among immunocompromised and immunonaive individuals. HCMV-induced signaling initiated during viral entry stimulates a rapid noncanonical activation of Akt to drive the differentiation of short-lived monocytes into long-lived macrophages, which is essential for viral dissemination and persistence. We found that HCMV glycoproteins gB and gH directly bind and activate cellular epidermal growth factor receptor (EGFR) and integrin β1, respectively, to reshape canonical Akt signaling within monocytes. The remodeling of the Akt signaling network was due to the recruitment of nontraditional Akt activators to either the gB- or gH-generated receptor signaling complexes. Phosphoinositide 3-kinase (PI3K) comprised of the p110β catalytic subunit was recruited to the gB/EGFR complex despite p110δ being the primary PI3K isoform found within monocytes. Concomitantly, SH2 domain-containing inositol 5-phosphatase 1 (SHIP1) was recruited to the gH/integrin β1 complex, which is critical to aberrant Akt activation, as SHIP1 diverts PI3K signaling toward a noncanonical pathway. Although integrin β1 was required for SHIP1 recruitment, gB-activated EGFR mediated SHIP1 activation, underscoring the importance of the interplay between gB- and gH-mediated signaling to the unique activation of Akt during HCMV infection. Indeed, SHIP1 activation mediated the increased expression of Mcl-1 and HSP27, two Akt-dependent antiapoptotic proteins specifically upregulated during HCMV infection but not during growth factor treatment. Overall, our data indicate that HCMV glycoproteins gB and gH work in concert to initiate an HCMV-specific signalosome responsible for the atypical activation of Akt required for infected monocyte survival and ultimately viral persistence.IMPORTANCE Human cytomegalovirus (HCMV) infection is endemic throughout the world regardless of socioeconomic conditions and geographic locations with a seroprevalence reaching up to 100% in some developing countries. Although asymptomatic in healthy individuals, HCMV can cause severe multiorgan disease in immunocompromised or immunonaive patients. HCMV disease is a direct consequence of monocyte-mediated systematic spread of the virus following infection. Because monocytes are short-lived cells, HCMV must subvert the natural short life-span of these blood cells by inducing a distinct activation of Akt, a serine/theonine protein kinase. In this work, we demonstrate that HCMV glycoproteins gB and gH work in tandem to reroute classical host cellular receptor signaling to aberrantly activate Akt and drive survival of infected monocytes. Deciphering how HCMV modulates the cellular pathway to induce monocyte survival is important to develop a new class of anti-HCMV drugs that could target and prevent spread of the virus by eliminating infected monocytes.
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Adamson CS, Nevels MM. Bright and Early: Inhibiting Human Cytomegalovirus by Targeting Major Immediate-Early Gene Expression or Protein Function. Viruses 2020; 12:v12010110. [PMID: 31963209 PMCID: PMC7019229 DOI: 10.3390/v12010110] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/11/2022] Open
Abstract
The human cytomegalovirus (HCMV), one of eight human herpesviruses, establishes lifelong latent infections in most people worldwide. Primary or reactivated HCMV infections cause severe disease in immunosuppressed patients and congenital defects in children. There is no vaccine for HCMV, and the currently approved antivirals come with major limitations. Most approved HCMV antivirals target late molecular processes in the viral replication cycle including DNA replication and packaging. “Bright and early” events in HCMV infection have not been exploited for systemic prevention or treatment of disease. Initiation of HCMV replication depends on transcription from the viral major immediate-early (IE) gene. Alternative transcripts produced from this gene give rise to the IE1 and IE2 families of viral proteins, which localize to the host cell nucleus. The IE1 and IE2 proteins are believed to control all subsequent early and late events in HCMV replication, including reactivation from latency, in part by antagonizing intrinsic and innate immune responses. Here we provide an update on the regulation of major IE gene expression and the functions of IE1 and IE2 proteins. We will relate this insight to experimental approaches that target IE gene expression or protein function via molecular gene silencing and editing or small chemical inhibitors.
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Jacquet C, Marschall M, Andouard D, El Hamel C, Chianea T, Tsogoeva SB, Hantz S, Alain S. A highly potent trimeric derivative of artesunate shows promising treatment profiles in experimental models for congenital HCMV infection in vitro and ex vivo. Antiviral Res 2019; 175:104700. [PMID: 31870762 DOI: 10.1016/j.antiviral.2019.104700] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/09/2019] [Accepted: 12/17/2019] [Indexed: 01/10/2023]
Affiliation(s)
- Chloé Jacquet
- Université Limoges, UMR1092, 2 rue du Pr Descottes, 87000, Limoges, France; INSERM, UMR 1092, 2 rue du Pr Descottes, 87000, Limoges, France
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Schlossgarten 4, 91054, Erlangen, Germany
| | - Déborah Andouard
- Université Limoges, UMR1092, 2 rue du Pr Descottes, 87000, Limoges, France; INSERM, UMR 1092, 2 rue du Pr Descottes, 87000, Limoges, France; National Reference Center for Herpesviruses, Virology department, CHU Limoges, 2 rue Martin Luther King, 87000, Limoges, France
| | - Charhazed El Hamel
- Mother and Child Biobank (CB-HME), Pediatric department, Hôpital de la mère et de l'enfant, CHU Limoges, Limoges, France
| | - Thierry Chianea
- Department of Biochemistry and molecular Genetics, CHU Limoges, France
| | - Svetlana B Tsogoeva
- Organic Chemistry Chair I and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander University of Erlangen-Nürnberg, Nikolaus-Fiebiger-Straße 10, 91058, Erlangen, Germany
| | - Sébastien Hantz
- Université Limoges, UMR1092, 2 rue du Pr Descottes, 87000, Limoges, France; INSERM, UMR 1092, 2 rue du Pr Descottes, 87000, Limoges, France; National Reference Center for Herpesviruses, Virology department, CHU Limoges, 2 rue Martin Luther King, 87000, Limoges, France
| | - Sophie Alain
- Université Limoges, UMR1092, 2 rue du Pr Descottes, 87000, Limoges, France; INSERM, UMR 1092, 2 rue du Pr Descottes, 87000, Limoges, France; National Reference Center for Herpesviruses, Virology department, CHU Limoges, 2 rue Martin Luther King, 87000, Limoges, France.
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Leone F, Gigliotti P, La Russa A, Lofaro D, Perri A, Vizza D, Lupinacci S, Toteda G, Bonofiglio M, Presta P, Talarico R, Aquino B, Bonofiglio R. NFKB1 promoter polymorphism: A new predictive marker of cytomegalovirus infection after kidney transplantation. Transpl Infect Dis 2018; 21:e13027. [PMID: 30431214 DOI: 10.1111/tid.13027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 10/11/2018] [Accepted: 10/25/2018] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Cytomegalovirus (CMV) infection represents a common cause of morbidity and mortality in kidney transplant recipients (KTR). The NF-kB signaling pathway is highly involved in the pathogenesis of CMV infection. The -94ins/delATTG functional polymorphism in the promoter of NFKB1 has been associated with low intracellular levels of the protein and high incidence of inflammatory and autoimmune disease. In this study, we evaluated the association of this NFKB1 polymorphism with the risk of CMV infection. METHODS CMV infection was defined as virus isolation or detection of viral antigens or nucleic acid in any body fluid or tissue specimen. Using Cox regression and survival analysis, we analyzed the association between the polymorphism and CMV infection as well as recurrence in the first 12 months after transplantation. RESULTS We analyzed the -94ins/delATTG NFKB1 polymorphism of 189 KTRs. The 65% of CMV infections occurred in ins/ins group. Survival free from CMV infection was 54.7% for ins/ins group and 79.4% for deletion carriers one year after transplantation (P < 0.0001). At multivariate regression, deletion carriers showed a lower risk of CMV infection and recurrence with respect to ins/ins KTRs (HR = 0.224 P = 0.0002; HR = 0.307, P = 0.012, respectively). CONCLUSIONS In conclusion, pretransplantation screening for NFKB1 -94ins/delATTG polymorphism may predict CMV infection and improve the management of patients at higher risk of infection in the post-transplant period.
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Affiliation(s)
- Francesca Leone
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Paolo Gigliotti
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Antonella La Russa
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Danilo Lofaro
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Anna Perri
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Donatella Vizza
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Simona Lupinacci
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Giuseppina Toteda
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Martina Bonofiglio
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Pierangela Presta
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Roberta Talarico
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Benedetta Aquino
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
| | - Renzo Bonofiglio
- Kidney and Transplantation" Research Center, Department of Nephrology, Dialysis and Transplantation, Annunziata Hospital, Cosenza, Italy
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12
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Marques M, Ferreira AR, Ribeiro D. The Interplay between Human Cytomegalovirus and Pathogen Recognition Receptor Signaling. Viruses 2018; 10:v10100514. [PMID: 30241345 PMCID: PMC6212889 DOI: 10.3390/v10100514] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/15/2018] [Accepted: 09/19/2018] [Indexed: 12/26/2022] Open
Abstract
The cellular antiviral innate immune response is triggered upon recognition of specific viral components by a set of the host’s cytoplasmic or membrane-bound receptors. This interaction induces specific signaling cascades that culminate with the production of interferons and the expression of interferon-stimulated genes and pro-inflammatory cytokines that act as antiviral factors, suppressing viral replication and restricting infection. Here, we review and discuss the different mechanisms by which each of these receptors is able to recognize and signal infection by the human cytomegalovirus (HCMV), an important human pathogen mainly associated with severe brain defects in newborns and disabilities in immunocompromised individuals. We further present and discuss the many sophisticated strategies developed by HCMV to evade these different signaling mechanisms and counteract the cellular antiviral response, in order to support cell viability and sustain its slow replication cycle.
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Affiliation(s)
- Mariana Marques
- Institute of Biomedicine-iBiMED-and Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Ana Rita Ferreira
- Institute of Biomedicine-iBiMED-and Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Daniela Ribeiro
- Institute of Biomedicine-iBiMED-and Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal.
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13
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Hahn F, Fröhlich T, Frank T, Bertzbach LD, Kohrt S, Kaufer BB, Stamminger T, Tsogoeva SB, Marschall M. Artesunate-derived monomeric, dimeric and trimeric experimental drugs - Their unique mechanistic basis and pronounced antiherpesviral activity. Antiviral Res 2018; 152:104-110. [PMID: 29458133 DOI: 10.1016/j.antiviral.2018.02.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/06/2018] [Accepted: 02/13/2018] [Indexed: 12/24/2022]
Abstract
Human cytomegalovirus (HCMV) is a major human pathogen and is associated with severe pathology, such as life-threatening courses of infection in immunocompromised individuals and neonates. Currently, antiviral therapy is still hampered by a considerable toxicity of the available drugs and induction of viral resistance. Recently, we and others reported the very potent antiviral activity of the broad antiinfective drug artesunate in vitro and in vivo. Here, we investigated further optimized analogs including monomeric, dimeric and trimeric derivatives belonging to this highly interesting chemical group of experimental drugs (sesquiterpenes/trioxanes) and compared these to the previously identified trimeric artesunate compound TF27. We could demonstrate that (i) seven of the eight investigated monomeric, dimeric and trimeric artesunate derivatives, i.e. TF79, TF85, TF87, TF93.2.4, TF111, TF57a and TF57ab, exerted a strong anti-HCMV activity in primary human fibroblasts, (ii) the EC50 values ranged in the low to sub-micromolar concentrations and indicated a higher antiviral potency than the recently described artesunate analogs, (iii) one trimeric compound, TF79, showed a very promising EC50 of 0.03 ± 0.00 μM, which even exceled the antiviral potency of TF27 (EC50 0.04 ± 0.01 μM), (iv) levels of cytotoxicity (quantitative measurement of lactate dehydrogenase release) were low in a range between 100 and 30 μM and thus different from antiviral concentrations, (v) an analysis of protein expression levels indicated a potent block of viral protein expression, and (vi) data from a NF-κB reporter cell system strongly suggested that these compounds share the same antiviral mechanism. Taken together, our data on these novel compounds strongly encourages our earlier concept on the oligomerization and hybridization of artesunate analogs, providing an excellent platform for the generation of antiherpesviral drugs.
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Affiliation(s)
- Friedrich Hahn
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany.
| | - Tony Fröhlich
- Institute of Organic Chemistry I, Friedrich-Alexander University of Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058 Erlangen, Germany.
| | - Theresa Frank
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany.
| | - Luca D Bertzbach
- Institute of Virology, Freie Universität Berlin, Robert Von Ostertag-Str. 7 - 13, 14163 Berlin, Germany.
| | - Stephan Kohrt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany.
| | - Benedikt B Kaufer
- Institute of Virology, Freie Universität Berlin, Robert Von Ostertag-Str. 7 - 13, 14163 Berlin, Germany.
| | - Thomas Stamminger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany.
| | - Svetlana B Tsogoeva
- Institute of Organic Chemistry I, Friedrich-Alexander University of Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058 Erlangen, Germany.
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany.
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14
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Human Cytomegalovirus Utilizes a Nontraditional Signal Transducer and Activator of Transcription 1 Activation Cascade via Signaling through Epidermal Growth Factor Receptor and Integrins To Efficiently Promote the Motility, Differentiation, and Polarization of Infected Monocytes. J Virol 2017; 91:JVI.00622-17. [PMID: 29021395 DOI: 10.1128/jvi.00622-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 09/18/2017] [Indexed: 12/12/2022] Open
Abstract
Human cytomegalovirus (HCMV) infects peripheral blood monocytes and triggers biological changes that promote viral dissemination and persistence. We have shown that HCMV induces a proinflammatory state in infected monocytes, resulting in enhanced monocyte motility and transendothelial migration, prolonged monocyte survival, and differentiation toward a long-lived M1-like macrophage phenotype. Our data indicate that HCMV triggers these changes, in the absence of de novo viral gene expression and replication, through engagement and activation of epidermal growth factor receptor (EGFR) and integrins on the surface of monocytes. We previously identified that HCMV induces the upregulation of multiple proinflammatory gene ontologies, with the interferon-associated gene ontology exhibiting the highest percentage of upregulated genes. However, the function of the HCMV-induced interferon (IFN)-stimulated genes (ISGs) in infected monocytes remained unclear. We now show that HCMV induces the enhanced expression and activation of a key ISG transcriptional regulator, signal transducer and activator of transcription (STAT1), via an IFN-independent but EGFR- and integrin-dependent signaling pathway. Furthermore, we identified a biphasic activation of STAT1 that likely promotes two distinct phases of STAT1-mediated transcriptional activity. Moreover, our data show that STAT1 is required for efficient early HCMV-induced enhanced monocyte motility and later for HCMV-induced monocyte-to-macrophage differentiation and for the regulation of macrophage polarization, suggesting that STAT1 may serve as a molecular convergence point linking the biological changes that occur at early and later times postinfection. Taken together, our results suggest that HCMV reroutes the biphasic activation of a traditionally antiviral gene product through an EGFR- and integrin-dependent pathway in order to help promote the proviral activation and polarization of infected monocytes.IMPORTANCE HCMV promotes multiple functional changes in infected monocytes that are required for viral spread and persistence, including their enhanced motility and differentiation/polarization toward a proinflammatory M1 macrophage. We now show that HCMV utilizes the traditionally IFN-associated gene product, STAT1, to promote these changes. Our data suggest that HCMV utilizes EGFR- and integrin-dependent (but IFN-independent) signaling pathways to induce STAT1 activation, which may allow the virus to specifically dictate the biological activity of STAT1 during infection. Our data indicate that HCMV utilizes two phases of STAT1 activation, which we argue molecularly links the biological changes that occur following initial binding to those that continue to occur days to weeks following infection. Furthermore, our findings may highlight a unique mechanism for how HCMV avoids the antiviral response during infection by hijacking the function of a critical component of the IFN response pathway.
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15
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Wang D, Dai W, Wu J, Wang J. Improving transcriptional activity of human cytomegalovirus major immediate-early promoter by mutating NF-κB binding sites. Protein Expr Purif 2017; 142:16-24. [PMID: 28941824 DOI: 10.1016/j.pep.2017.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/12/2017] [Accepted: 09/18/2017] [Indexed: 01/11/2023]
Abstract
Many mammalian gene expression vectors express the transferred genes under the control of the cytomegalovirus (CMV) major immediate-early promoter (MIEP). The human MIEP has been known as the strongest promoter in mammalian cells and utilized widely in mammalian expression systems. There are four NF-κB binding sites (named as κBs) in the human MIEP. In this study, we have constructed multiple mutated MIEPs by changing the natural κBs in the human MIEP into the high-affinity artificial sequences that were in vitro selected by using systematic evolution of ligands by exponential enrichment (SELEX) and predicted by bioinformatics. With various transcriptional activity evaluations, we found three mutated MIEPs with the transcriptional activity higher than the wild-type MIEP, which should be useful and widely applicable in many mammalian transgene expression fields such as gene engineering, gene therapy and gene editing. This study provides a useful approach for promoter engineering in biotechnology. This study also produced a series of mutated MIEPs with various transcriptional activities, which may be used for the fine control of gene expression output in the future synthetic biology.
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Affiliation(s)
- Danyang Wang
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China
| | - Wei Dai
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China
| | - Jian Wu
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China
| | - Jinke Wang
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China.
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16
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Hancock MH, Nelson JA. Modulation of the NFκb Signalling Pathway by Human Cytomegalovirus. VIROLOGY (HYDERABAD) 2017; 1:104. [PMID: 29082387 PMCID: PMC5659363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Many viruses trigger innate and adaptive immune responses and must circumvent the negative consequences to successfully establish infection in their hosts. Human Cytomegalovirus (HCMV) is no exception, and devotes a significant portion of its coding capacity to genes involved in immune evasion. Activation of the NFκB signalling pathway by viral binding and entry results in induction of antiviral and pro-inflammatory genes that have significant negative effects on HCMV infection. However, NFκB signalling stimulates transcription from the Major Immediate Early Promoter (MIEP) and pro-inflammatory signalling is crucial for cellular differentiation and viral reactivation from latency. Accordingly, HCMV encodes proteins that act to both stimulate and inhibit the NFκB signalling pathway. In this Review we will highlight the complex interactions between HCMV and NFκB, discussing the known agonists and antagonists encoded by the virus and suggest why manipulation of the pathway may be critical for both lytic and latent infections.
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Affiliation(s)
- Meaghan H Hancock
- Corresponding author: Meaghan H. Hancock, Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, USA, Tel: 503-418-2784;
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17
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Cao L, Chen J, Wei Y, Shi H, Zhang X, Yuan J, Shi D, Liu J, Zhu X, Wang X, Cui S, Feng L. Porcine parvovirus induces activation of NF-κB signaling pathways in PK-15 cells mediated by toll-like receptors. Mol Immunol 2017; 85:248-255. [PMID: 28340426 DOI: 10.1016/j.molimm.2016.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 01/18/2023]
Abstract
Porcine parvovirus (PPV) is a pathogenic factor that primarily induces severe reproductive failure of pregnant swine, which results in extensive losses to the swine industry worldwide. In this study, a potential mechanism of PPV-induced activation of the nuclear transcription factor-kappaB (NF-κB) by infection in porcine kidney cells (PK-15) was elucidated for the first time. The subcellular localization of p65 analyzed by immunofluorescence assay (IFA) showed that PPV infection induced p65 translocation from the cytoplasm to the nucleus. p65 phosphorylation was detected in PK-15 cells with progression of PPV infection. NF-κB-regulated gene expression was enhanced in a viral dose-dependent manner using the NF-κB luciferase reporter assay system. Furthermore, PPV-induced NF-κB activation was closely related to the inhibitory kappa B alpha (IκBα) degradation. Treatment with a NF-κB-specific inhibitor demonstrated that the production of PPV progeny viruses was enhanced to some extent. In addition, these results demonstrated that the adapter molecule TIR domain-containing adapter inducing IFN-β (TRIF) and myeloid differentiation primary-response protein 88 (MyD88)-dependent signaling pathways were involved in PPV-induced NF-κB activation. Together, these results provide evidence that the toll-like receptor (TLR) pathway participates in recognition of PPV and induction of NF-κB activation, and add to understanding of the molecular mechanisms underlying PPV infection.
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Affiliation(s)
- Liyan Cao
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Jianfei Chen
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Yanwu Wei
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Hongyan Shi
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Xin Zhang
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Jing Yuan
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Da Shi
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Jianbo Liu
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Xiangdong Zhu
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Xin Wang
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Shangjin Cui
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China
| | - Li Feng
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150040, China.
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18
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Kim JH, Collins-McMillen D, Buehler JC, Goodrum FD, Yurochko AD. Human Cytomegalovirus Requires Epidermal Growth Factor Receptor Signaling To Enter and Initiate the Early Steps in the Establishment of Latency in CD34 + Human Progenitor Cells. J Virol 2017; 91:e01206-16. [PMID: 27974567 PMCID: PMC5309964 DOI: 10.1128/jvi.01206-16] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 12/06/2016] [Indexed: 01/11/2023] Open
Abstract
The establishment of human cytomegalovirus (HCMV) latency and persistence relies on the successful infection of hematopoietic cells, which serve as sites of viral persistence and contribute to viral spread. Here, using blocking antibodies and pharmacological inhibitors, we document that HCMV activation of the epidermal growth factor receptor (EGFR) and downstream phosphatidylinositol 3-kinase (PI3K) mediates viral entry into CD34+ human progenitor cells (HPCs), resulting in distinct cellular trafficking and nuclear translocation of the virus compared to that in other immune cells, such as we have documented in monocytes. We argue that the EGFR allows HCMV to regulate the cellular functions of these replication-restricted cells via its signaling activity following viral binding. In addition to regulating HCMV entry/trafficking, EGFR signaling may also shape the early steps required for the successful establishment of viral latency in CD34+ cells, as pharmacological inhibition of EGFR increases the transcription of lytic IE1/IE2 mRNA while curbing the expression of latency-associated UL138 mRNA. EGFR signaling following infection of CD34+ HPCs may also contribute to changes in hematopoietic potential, as treatment with the EGFR kinase (EGFRK) inhibitor AG1478 alters the expression of the cellular hematopoietic cytokine interleukin 12 (IL-12) in HCMV-infected cells but not in mock-infected cells. These findings, along with our previous work with monocytes, suggest that EGFR likely serves as an important determinant of HCMV tropism for select subsets of hematopoietic cells. Moreover, our new data suggest that EGFR is a key receptor for efficient viral entry and that the ensuing signaling regulates important early events required for successful infection of CD34+ HPCs by HCMV.IMPORTANCE HCMV establishes lifelong persistence within the majority of the human population without causing overt pathogenesis in healthy individuals. Despite this, reactivation of HCMV from its latent reservoir in the bone marrow causes significant morbidity and mortality in immunologically compromised individuals, such as bone marrow and solid organ transplant patients. Lifelong persistent infection has also been linked with the development of various cardiovascular diseases in otherwise healthy individuals. Current HCMV therapeutics target lytic replication, but not the latent viral reservoir; thus, an understanding of the molecular basis for viral latency and persistence is paramount to controlling or eliminating HCMV infection. Here, we show that the viral signalosome activated by HCMV binding to its entry receptor, EGFR, in CD34+ HPCs initiates early events necessary for successful latent infection of this cell type. EGFR and associated signaling players may therefore represent promising targets for mitigating HCMV persistence.
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Affiliation(s)
- Jung Heon Kim
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology, Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Donna Collins-McMillen
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology, Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | | | - Felicia D Goodrum
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
- Department of Cellular and Molecular Medicine, Department of Immunobiology, Department of Molecular and Cellular Biology, University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
| | - Andrew D Yurochko
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology, Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
- Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
- Center of Excellence in Arthritis and Rheumatology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
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19
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Campadelli-Fiume G, Collins-McMillen D, Gianni T, Yurochko AD. Integrins as Herpesvirus Receptors and Mediators of the Host Signalosome. Annu Rev Virol 2016; 3:215-236. [PMID: 27501260 DOI: 10.1146/annurev-virology-110615-035618] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The repertoire of herpesvirus receptors consists of nonintegrin and integrin molecules. Integrins interact with the conserved glycoproteins gH/gL or gB. This interaction is a conserved biology across the Herpesviridae family, likely directed to promote virus entry and endocytosis. Herpesviruses exploit this interaction to execute a range of critical functions that include (a) relocation of nonintegrin receptors (e.g., herpes simplex virus nectin1 and Kaposi's sarcoma-associated herpesvirus EphA2), or association with nonintegrin receptors (i.e., human cytomegalovirus EGFR), to dictate species-specific entry pathways; (b) activation of multiple signaling pathways (e.g., Ca2+ release, c-Src, FAK, MAPK, and PI3K); and (c) association with Rho GTPases, tyrosine kinase receptors, Toll-like receptors, which result in cytoskeletal remodeling, differential cell type targeting, and innate responses. In turn, integrins can be modulated by viral proteins (e.g., Epstein-Barr virus LMPs) to favor spread of transformed cells. We propose that herpesviruses evolved a multipartite entry system to allow interaction with multiple receptors, including integrins, required for their sophisticated life cycle.
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Affiliation(s)
- Gabriella Campadelli-Fiume
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, 40126 Bologna, Italy;
| | - Donna Collins-McMillen
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology, and Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130;
| | - Tatiana Gianni
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, 40126 Bologna, Italy;
| | - Andrew D Yurochko
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology, and Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130; .,Feist-Weiller Cancer Center and Center for Excellence in Arthritis and Rheumatology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130
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20
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Collins-McMillen D, Kim JH, Nogalski MT, Stevenson EV, Chan GC, Caskey JR, Cieply SJ, Yurochko AD. Human Cytomegalovirus Promotes Survival of Infected Monocytes via a Distinct Temporal Regulation of Cellular Bcl-2 Family Proteins. J Virol 2015; 90:2356-71. [PMID: 26676786 PMCID: PMC4810730 DOI: 10.1128/jvi.01994-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 12/04/2015] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Monocytes play a key role in the hematogenous dissemination of human cytomegalovirus (HCMV) to target organ systems. To infect monocytes and reprogram them to deliver infectious virus, HCMV must overcome biological obstacles, including the short life span of monocytes and their antiviral proapoptotic response to infection. We have shown that virally induced upregulation of cellular Mcl-1 promotes early survival of HCMV-infected monocytes, allowing cells to overcome an early apoptotic checkpoint at around 48 h postinfection (hpi). Here, we demonstrate an HCMV-dependent shift from Mcl-1 as the primary antiapoptotic player to the related protein, Bcl-2, later during infection. Bcl-2 was upregulated in HCMV-infected monocytes beginning at 48 hpi. Treatment with the Bcl-2 antagonist ABT-199 only reduced the prosurvival effects of HCMV in target monocytes beginning at 48 hpi, suggesting that Mcl-1 controls survival prior to 48 hpi, while Bcl-2 promotes survival after 48 hpi. Although Bcl-2 was upregulated following viral binding/signaling through cellular integrins (compared to Mcl-1, which is upregulated through binding/activation of epidermal growth factor receptor [EGFR]), it functioned similarly to Mcl-1, adopting the early role of Mcl-1 in preventing caspase-3 cleavage/activation. This distinct, HCMV-induced shift from Mcl-1 to Bcl-2 occurs in response to a cellular upregulation of proapoptotic Bax, as small interfering RNA (siRNA)-mediated knockdown of Bax reduced the upregulation of Bcl-2 in infected monocytes and rescued the cells from the apoptotic effects of Bcl-2 inhibition. Our data demonstrate a distinct survival strategy whereby HCMV induces a biphasic regulation of cellular Bcl-2 proteins to promote host cell survival, leading to viral dissemination and the establishment of persistent HCMV infection. IMPORTANCE Hematogenous dissemination of HCMV via infected monocytes is a crucial component of the viral survival strategy and is required for the establishment of persistent infection and for viral spread to additional hosts. Our system of infected primary human blood monocytes provides us with an opportunity to answer specific questions about viral spread and persistence in in vivo-relevant myeloid cells that cannot be addressed with the more traditionally used replication-permissive cells. Our goal in examining the mechanisms whereby HCMV reprograms infected monocytes to promote viral dissemination is to uncover new targets for therapeutic intervention that would disrupt key viral survival and persistence strategies. Because of this important role in maintaining survival of HCMV-infected monocytes, our new data on the role of Bcl-2 regulation during viral infection represents a promising molecular target for mitigating viral spread and persistence.
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Affiliation(s)
- Donna Collins-McMillen
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Jung Heon Kim
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Maciej T Nogalski
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Emily V Stevenson
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Gary C Chan
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Joshua R Caskey
- Science and Medicine Academic Research Training Program, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Stephen J Cieply
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Andrew D Yurochko
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
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21
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Hutterer C, Niemann I, Milbradt J, Fröhlich T, Reiter C, Kadioglu O, Bahsi H, Zeitträger I, Wagner S, Einsiedel J, Gmeiner P, Vogel N, Wandinger S, Godl K, Stamminger T, Efferth T, Tsogoeva SB, Marschall M. The broad-spectrum antiinfective drug artesunate interferes with the canonical nuclear factor kappa B (NF-κB) pathway by targeting RelA/p65. Antiviral Res 2015; 124:101-9. [PMID: 26546752 DOI: 10.1016/j.antiviral.2015.10.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 12/27/2022]
Abstract
Infection with human cytomegalovirus (HCMV) is a serious medical problem, particularly in immunocompromised individuals and neonates. The success of standard antiviral therapy is hampered by low drug compatibility and induction of viral resistance. A novel strategy is based on the exploitation of cell-directed signaling inhibitors. The broad antiinfective drug artesunate (ART) offers additional therapeutic options such as oral bioavailability and low levels of toxic side-effects. Here, novel ART-derived compounds including dimers and trimers were synthesized showing further improvements over the parental drug. Antiviral activity and mechanistic aspects were determined leading to the following statements: (i) ART exerts antiviral activity towards human and animal herpesviruses, (ii) no induction of ART-resistant HCMV mutants occurred in vitro, (iii) chemically modified derivatives of ART showed strongly enhanced anti-HCMV efficacy, (iv) NF-κB reporter constructs, upregulated during HCMV replication, could be partially blocked by ART treatment, (v) ART activity analyzed in stable reporter cell clones indicated an inhibition of stimulated NF-κB but not CREB pathway, (vi) solid-phase immobilized ART was able to bind to NF-κB RelA/p65, and (vii) peptides within NF-κB RelA/p65 represent candidates of ART binding as analyzed by in silico docking and mass spectrometry. These novel findings open new prospects for the future medical use of ART and ART-related drug candidates.
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Affiliation(s)
- Corina Hutterer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ina Niemann
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Tony Fröhlich
- Institute of Organic Chemistry I, FAU, Erlangen, Germany
| | | | - Onat Kadioglu
- Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
| | - Hanife Bahsi
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Isabel Zeitträger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Jürgen Einsiedel
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, FAU, Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, FAU, Erlangen, Germany
| | - Nico Vogel
- Institute for Biochemistry, Biochemistry and Molecular Medicine, Emil Fischer Center, FAU, Erlangen, Germany
| | | | | | - Thomas Stamminger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Thomas Efferth
- Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
| | | | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany.
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Human Cytomegalovirus Infection Dysregulates the Localization and Stability of NICD1 and Jag1 in Neural Progenitor Cells. J Virol 2015; 89:6792-804. [PMID: 25903338 DOI: 10.1128/jvi.00351-15] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 04/10/2015] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Human cytomegalovirus (HCMV) infection of the developing fetus frequently results in major neural developmental damage. In previous studies, HCMV was shown to downregulate neural progenitor/stem cell (NPC) markers and induce abnormal differentiation. As Notch signaling plays a vital role in the maintenance of stem cell status and is a switch that governs NPC differentiation, the effect of HCMV infection on the Notch signaling pathway in NPCs was investigated. HCMV downregulated mRNA levels of Notch1 and its ligand, Jag1, and reduced protein levels and altered the intracellular localization of Jag1 and the intracellular effector form of Notch1, NICD1. These effects required HCMV gene expression and appeared to be mediated through enhanced proteasomal degradation. Transient expression of the viral tegument proteins of pp71 and UL26 reduced NICD1 and Jag1 protein levels endogenously and exogenously. Given the critical role of Notch signaling in NPC growth and differentiation, these findings reveal important mechanisms by which HCMV disturbs neural cell development in vitro. Similar events in vivo may be associated with HCMV-mediated neuropathogenesis during congenital infection in the fetal brain. IMPORTANCE Congenital human cytomegalovirus (HCMV) infection is the leading cause of birth defects that primarily manifest as neurological disabilities. Neural progenitor cells (NPCs), key players in fetal brain development, are the most susceptible cell type for HCMV infection in the fetal brain. Studies have shown that NPCs are fully permissive for HCMV infection, which causes neural cell loss and premature differentiation, thereby perturbing NPC fate. Elucidation of virus-host interactions that govern NPC proliferation and differentiation is critical to understanding neuropathogenesis. The Notch signaling pathway is critical for maintaining stem cell status and functions as a switch for differentiation of NPCs. Our investigation into the impact of HCMV infection on this pathway revealed that HCMV dysregulates Notch signaling by altering expression of the Notch ligand Jag1, Notch1, and its active effector in NPCs. These results suggest a mechanism for the neuropathogenesis induced by HCMV infection that includes altered NPC differentiation and proliferation.
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23
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Kropp KA, Hsieh WY, Isern E, Forster T, Krause E, Brune W, Angulo A, Ghazal P. A temporal gate for viral enhancers to co-opt Toll-like-receptor transcriptional activation pathways upon acute infection. PLoS Pathog 2015; 11:e1004737. [PMID: 25856589 PMCID: PMC4391941 DOI: 10.1371/journal.ppat.1004737] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 02/09/2015] [Indexed: 12/27/2022] Open
Abstract
Viral engagement with macrophages activates Toll-Like-Receptors (TLRs) and viruses must contend with the ensuing inflammatory responses to successfully complete their replication cycle. To date, known counter-strategies involve the use of viral-encoded proteins that often employ mimicry mechanisms to block or redirect the host response to benefit the virus. Whether viral regulatory DNA sequences provide an opportunistic strategy by which viral enhancer elements functionally mimic innate immune enhancers is unknown. Here we find that host innate immune genes and the prototypical viral enhancer of cytomegalovirus (CMV) have comparable expression kinetics, and positively respond to common TLR agonists. In macrophages but not fibroblasts we show that activation of NFκB at immediate-early times of infection is independent of virion-associated protein, M45. We find upon virus infection or transfection of viral genomic DNA the TLR-agonist treatment results in significant enhancement of the virus transcription-replication cycle. In macrophage time-course infection experiments we demonstrate that TLR-agonist stimulation of the viral enhancer and replication cycle is strictly delimited by a temporal gate with a determined half-maximal time for enhancer-activation of 6 h; after which TLR-activation blocks the viral transcription-replication cycle. By performing a systematic siRNA screen of 149 innate immune regulatory factors we identify not only anticipated anti-viral and pro-viral contributions but also new factors involved in the CMV transcription-replication cycle. We identify a central convergent NFκB-SP1-RXR-IRF axis downstream of TLR-signalling. Activation of the RXR component potentiated direct and indirect TLR-induced activation of CMV transcription-replication cycle; whereas chromatin binding experiments using wild-type and enhancer-deletion virus revealed IRF3 and 5 as new pro-viral host transcription factor interactions with the CMV enhancer in macrophages. In a series of pharmacologic, siRNA and genetic loss-of-function experiments we determined that signalling mediated by the TLR-adaptor protein MyD88 plays a vital role for governing the inflammatory activation of the CMV enhancer in macrophages. Downstream TLR-regulated transcription factor binding motif disruption for NFκB, AP1 and CREB/ATF in the CMV enhancer demonstrated the requirement of these inflammatory signal-regulated elements in driving viral gene expression and growth in cells as well as in primary infection of neonatal mice. Thus, this study shows that the prototypical CMV enhancer, in a restricted time-gated manner, co-opts through DNA regulatory mimicry elements, innate-immune transcription factors to drive viral expression and replication in the face of on-going pro-inflammatory antiviral responses in vitro and in vivo and; suggests an unexpected role for inflammation in promoting acute infection and has important future implications for regulating latency. Here we discover how inflammatory signalling may unintentionally promote infection, as a result of viruses evolving DNA sequences, known as enhancers, which act as a bait to prey on the infected cell transcription factors induced by inflammation. The major inflammatory transcription factors activated are part of the TLR-signalling pathway. We find the prototypical viral enhancer of cytomegalovirus can be paradoxically boosted by activation of inflammatory “anti-viral” TLR-signalling independent of viral structural proteins. This leads to an increase in viral gene expression and replication in cell-culture and upon infection of mice. We identify an axis of inflammatory transcription factors, acting downstream of TLR-signalling but upstream of interferon inhibition. Mechanistically, the central TLR-adapter protein MyD88 is shown to play a critical role in promoting viral enhancer activity in the first 6h of infection. The co-option of TLR-signalling exceeds the usage of NFκB, and we identify IRF3 and 5 as newly found viral-enhancer interacting inflammatory transcription factors. Taken together this study reveals how virus enhancers, employ a path of least resistance by directly harnessing within a short temporal window, the activation of anti-viral signalling in macrophages to drive viral gene expression and replication to an extent that has not been recognised before.
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Affiliation(s)
- Kai A. Kropp
- Division of Pathway Medicine, Edinburgh Infectious Diseases, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (KAK); (PG)
| | - Wei Yuan Hsieh
- Division of Pathway Medicine, Edinburgh Infectious Diseases, University of Edinburgh, Edinburgh, United Kingdom
| | - Elena Isern
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain
| | - Thorsten Forster
- Division of Pathway Medicine, Edinburgh Infectious Diseases, University of Edinburgh, Edinburgh, United Kingdom
| | - Eva Krause
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Wolfram Brune
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Ana Angulo
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain
| | - Peter Ghazal
- Division of Pathway Medicine, Edinburgh Infectious Diseases, University of Edinburgh, Edinburgh, United Kingdom
- SynthSys, University of Edinburgh, The King’s Buildings, Edinburgh, United Kingdom
- * E-mail: (KAK); (PG)
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24
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Gardner TJ, Cohen T, Redmann V, Lau Z, Felsenfeld D, Tortorella D. Development of a high-content screen for the identification of inhibitors directed against the early steps of the cytomegalovirus infectious cycle. Antiviral Res 2014; 113:49-61. [PMID: 25446405 DOI: 10.1016/j.antiviral.2014.10.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 10/16/2014] [Accepted: 10/20/2014] [Indexed: 01/06/2023]
Abstract
Human cytomegalovirus (CMV) is a latent and persistent virus whose proliferation increases morbidity and mortality of immune-compromised individuals. The current anti-CMV therapeutics targeting the viral DNA polymerase or the major immediate-early (MIE) gene locus are somewhat effective at limiting CMV-associated disease. However, due to low bioavailability, severe toxicity, and the development of drug resistant CMV strains following prolonged treatment, current anti-CMV therapeutics are insufficient. To help address this shortfall, we established a high-content assay to identify inhibitors targeting CMV entry and the early steps of infection. The infection of primary human fibroblasts with a variant of the CMV laboratory strain AD169 expressing a chimeric IE2-yellow fluorescence protein (YFP) (AD169IE2-YFP) provided the basis for the high-content assay. The localization of IE2-YFP to the nucleus shortly following an AD169IE2-YFP infection induced a robust fluorescent signal that was quantified using confocal microscopy. The assay was optimized to achieve outstanding assay fitness and high Z' scores. We then screened a bioactive chemical library consisting of 2080 compounds and identified hit compounds based on the decrease of fluorescence signal from IE2-YFP nuclear expression. The hit compounds likely target various cellular processes involved in the early steps of infection including capsid transport, chromatin remodeling, and viral gene expression. Extensive secondary assays confirmed the ability of a hit compound, convallatoxin, to inhibit infection of both laboratory and clinical CMV strains and limit virus proliferation. Collectively, the data demonstrate that we have established a robust high-content screen to identify compounds that limit the early steps of the CMV life cycle, and that novel inhibitors of early infection events may serve as viable CMV therapeutics.
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Affiliation(s)
- Thomas J Gardner
- Icahn School of Medicine at Mount Sinai, Department of Microbiology, New York, NY 10029, USA
| | - Tobias Cohen
- Icahn School of Medicine at Mount Sinai, Department of Microbiology, New York, NY 10029, USA
| | - Veronika Redmann
- Icahn School of Medicine at Mount Sinai, Department of Microbiology, New York, NY 10029, USA
| | - Zerlina Lau
- Icahn School of Medicine at Mount Sinai, Integrated Screening Core, Experimental Therapeutics Institute, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Dan Felsenfeld
- Icahn School of Medicine at Mount Sinai, Integrated Screening Core, Experimental Therapeutics Institute, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Domenico Tortorella
- Icahn School of Medicine at Mount Sinai, Department of Microbiology, New York, NY 10029, USA
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25
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The human cytomegalovirus UL26 protein antagonizes NF-κB activation. J Virol 2014; 88:14289-300. [PMID: 25275128 DOI: 10.1128/jvi.02552-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Viral infection frequently triggers activation of host innate immune pathways that attempt to limit viral spread. The NF-κB pathway is a critical component that governs this response. We have found that the human cytomegalovirus (HCMV) U(L)26 protein antagonizes NF-κB activation. Upon infection, an HCMV strain lacking the U(L)26 gene (ΔU(L)26) induced the nuclear translocation of the NF-κB RelB subunit and activated expression and secretion of interleukin-6 (IL-6), an NF-κB target gene. The ΔU(L)26 mutant was also more sensitive to challenge with tumor necrosis factor alpha (TNF-α), a canonical NF-κB inducer. Further, expression of U(L)26 in the absence of other viral proteins blocked NF-κB activation induced by either TNF-α treatment or infection with Sendai virus (SeV). Our results indicate that U(L)26 expression is sufficient to block TNF-α-induced NF-κB nuclear translocation and IκB degradation. Last, U(L)26 blocks TNF-α-induced IκB-kinase (IKK) phosphorylation, a key step in NF-κB activation. Combined, our results indicate that U(L)26 is part of a viral program to antagonize innate immunity through modulation of NF-κB signaling. IMPORTANCE The NF-κB signaling pathway regulates innate immunity, an integral host process that limits viral pathogenesis. Viruses have evolved mechanisms to modulate NF-κB signaling to ensure their replication. HCMV is a major cause of birth defects and disease in immunosuppressed populations. HCMV is known to actively target the NF-κB pathway, which is important for HCMV infection. Our results indicate that the HCMV U(L)26 gene is a key modulator of NF-κB pathway activity. We find the U(L)26 gene is both necessary and sufficient to block NF-κB activation upon challenge with antiviral cytokines. Further, U(L)26 attenuates the phosphorylation and activation of a key NF-κB activating kinase complex, IKK. Our study provides new insight into how HCMV targets the NF-κB pathway. Given its importance to viral infection, the mechanisms through which viruses target the NF-κB pathway highlight areas of vulnerability that could be therapeutically targeted to attenuate viral replication.
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26
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A locus encompassing the Epstein-Barr virus bglf4 kinase regulates expression of genes encoding viral structural proteins. PLoS Pathog 2014; 10:e1004307. [PMID: 25166506 PMCID: PMC4148442 DOI: 10.1371/journal.ppat.1004307] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 07/01/2014] [Indexed: 12/17/2022] Open
Abstract
The mechanism regulating expression of late genes, encoding viral structural components, is an unresolved problem in the biology of DNA tumor viruses. Here we show that BGLF4, the only protein kinase encoded by Epstein-Barr virus (EBV), controls expression of late genes independent of its effect on viral DNA replication. Ectopic expression of BGLF4 in cells lacking the kinase gene stimulated the transcript levels of six late genes by 8- to 10-fold. Introduction of a BGLF4 mutant that eliminated its kinase activity did not stimulate late gene expression. In cells infected with wild-type EBV, siRNA to BGLF4 (siG4) markedly reduced late gene expression without compromising viral DNA replication. Synthesis of late products was restored upon expression of a form of BGLF4 resistant to the siRNA. Studying the EBV transcriptome using mRNA-seq during the late phase of the lytic cycle in the absence and presence of siG4 showed that BGLF4 controlled expression of 31 late genes. Analysis of the EBV transcriptome identified BGLF3 as a gene whose expression was reduced as a result of silencing BGLF4. Knockdown of BGLF3 markedly reduced late gene expression but had no effect on viral DNA replication or expression of BGLF4. Our findings reveal the presence of a late control locus encompassing BGLF3 and BGLF4 in the EBV genome, and provide evidence for the importance of both proteins in post-replication events that are necessary for expression of late genes.
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27
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Stevenson EV, Collins-McMillen D, Kim JH, Cieply SJ, Bentz GL, Yurochko AD. HCMV reprogramming of infected monocyte survival and differentiation: a Goldilocks phenomenon. Viruses 2014; 6:782-807. [PMID: 24531335 PMCID: PMC3939482 DOI: 10.3390/v6020782] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/04/2014] [Accepted: 02/04/2014] [Indexed: 12/14/2022] Open
Abstract
The wide range of disease pathologies seen in multiple organ sites associated with human cytomegalovirus (HCMV) infection results from the systemic hematogenous dissemination of the virus, which is mediated predominately by infected monocytes. In addition to their role in viral spread, infected monocytes are also known to play a key role in viral latency and life-long persistence. However, in order to utilize infected monocytes for viral spread and persistence, HCMV must overcome a number of monocyte biological hurdles, including their naturally short lifespan and their inability to support viral gene expression and replication. Our laboratory has shown that HCMV is able to manipulate the biology of infected monocytes in order to overcome these biological hurdles by inducing the survival and differentiation of infected monocytes into long-lived macrophages capable of supporting viral gene expression and replication. In this current review, we describe the unique aspects of how HCMV promotes monocyte survival and differentiation by inducing a “finely-tuned” macrophage cell type following infection. Specifically, we describe the induction of a uniquely polarized macrophage subset from infected monocytes, which we argue is the ideal cellular environment for the initiation of viral gene expression and replication and, ultimately, viral spread and persistence within the infected host.
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Affiliation(s)
- Emily V Stevenson
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Donna Collins-McMillen
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Jung Heon Kim
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Stephen J Cieply
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Gretchen L Bentz
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Andrew D Yurochko
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
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28
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Affiliation(s)
- Kai A. Kropp
- Division of Pathway Medicine and Edinburgh Infectious Diseases, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (KAK); (PG)
| | - Ana Angulo
- Facultad de Medicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain
| | - Peter Ghazal
- Division of Pathway Medicine and Edinburgh Infectious Diseases, University of Edinburgh, Edinburgh, United Kingdom
- SynthSys (Synthetic and Systems Biology), University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (KAK); (PG)
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29
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Human cytomegalovirus pUL83 stimulates activity of the viral immediate-early promoter through its interaction with the cellular IFI16 protein. J Virol 2010; 84:7803-14. [PMID: 20504932 DOI: 10.1128/jvi.00139-10] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The human cytomegalovirus (HCMV) virion protein pUL83 (also termed pp65) inhibits the expression of interferon-inducible cellular genes. In this work we demonstrate that pUL83 is also important for efficient induction of transcription from the viral major immediate-early promoter. Infection with a mutant virus containing a premature translation termination codon in the UL83 open reading frame (ORF) (UL83Stop) resulted in decreased transcription from the major immediate-early promoter in a time- and multiplicity-dependent manner. Expression of pUL83 alone is capable of transactivating the promoter in a reporter assay, and pUL83 associates with the promoter in infected cells. To investigate the mechanism by which the protein regulates the major immediate-early promoter, we utilized a mutant virus expressing an epitope-tagged pUL83 from its own promoter to identify protein binding partners for pUL83 during infection. We identified and confirmed the interaction of pUL83 with cellular IFI16 family members throughout the course of HCMV infection. pUL83 recruits IFI16 to the major immediate-early promoter, and IFI16 binding at the promoter is dependent upon the presence of pUL83. Consistent with the results obtained with the UL83Stop virus, infection of IFI16 knockdown cells with wild-type virus resulted in decreased levels of immediate-early transcripts compared to those of control cells. These data identify a previously unknown role for pUL83 in the initiation of the human cytomegalovirus gene expression cascade.
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30
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Khan KA, Coaquette A, Davrinche C, Herbein G. Bcl-3-regulated transcription from major immediate-early promoter of human cytomegalovirus in monocyte-derived macrophages. THE JOURNAL OF IMMUNOLOGY 2009; 182:7784-94. [PMID: 19494302 DOI: 10.4049/jimmunol.0803800] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Monocytes/macrophages are key cells in the pathogenesis of human CMV (HCMV) infection, but the in vitro rate of viral production in primary human monocyte-derived macrophages (MDM) is considerably lower than in fibroblasts. Considering that the NF-kappaB signaling pathway is potentially involved in the replication strategy of HCMV through efficient transactivation of the major immediate-early promoter (MIEP), efficient viral replication, and late gene expression, we investigated the composition of the NF-kappaB complex in HCMV-infected MDMs and fibroblasts. Preliminary studies showed that HCMV could grow in primary MDM culture but that the viral titer in culture supernatants was lower than that observed in the supernatants of more permissive MRC5 fibroblasts. EMSA and microwell colorimetric NF-kappaB assay demonstrated that HCMV infection of MDMs increased p52 binding activity without activating the canonical p50/p65 complex. Moreover, Bcl-3 was up-regulated and was demonstrated to associate with p52, indicating p52/Bcl-3 complexes as the major component of the NF-kappaB complex in MDMs. Luciferase assays in promonocytic U937 cells transfected with an MIEP-luciferase reporter construct demonstrated MIEP activation in response to p52 and Bcl-3 overexpression. Chromatin immunoprecipitation assay demonstrated that p52 and Bcl-3 bind the MIEP in acutely HCMV-infected MDMs. In contrast, HCMV infection of MRC5 fibroblasts resulted in activation of p50/p65 heterodimers. Thus, activation of p52/Bcl-3 complexes in MDMs and p50/p65 heterodimers in fibroblasts in response to HCMV infection might explain the low-level growth of the virus in MDMs vs efficient growth in fibroblasts.
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Affiliation(s)
- Kashif Aziz Khan
- Department of Virology, Institut Fédératif de Recherche 133, Equipe d'Accueil 3186, Franche-Comté University, Centre Hospitalier Universitaire de Besançon, Besançon, France
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31
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Poole E, Groves I, MacDonald A, Pang Y, Alcami A, Sinclair J. Identification of TRIM23 as a cofactor involved in the regulation of NF-kappaB by human cytomegalovirus. J Virol 2009; 83:3581-90. [PMID: 19176615 PMCID: PMC2663253 DOI: 10.1128/jvi.02072-08] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Accepted: 01/15/2009] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) regulates NF-kappaB during infection by a variety of mechanisms. For example, the HCMV gene product, UL144, is known to activate NF-kappaB in a tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6)-dependent manner, causing the upregulation of the chemokine CCL22 (MDC). Viral UL144 is expressed from the UL/b' region of the HCMV genome at early times postinfection and is a TNFR1-like homologue. Despite this homology to the TNFR1 receptor superfamily, UL144 does not bind to members of the TNF ligand superfamily. We show here that the upregulation of NF-kappaB by UL144 is dependent upon cellular tripartite motif 23 (TRIM23) protein. We propose a mechanism by which UL144 activates NF-kappaB through a direct interaction with the cellular protein TRIM23 in a complex containing TRAF6. In contrast, TRIM23 is not involved in conventional double-stranded RNA signaling via NF-kappaB. Therefore, we present a novel role for TRIM23 that is specific to UL144-mediated activation of NF-kappaB during the course of virus infection.
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Affiliation(s)
- Emma Poole
- Department of Medicine, University of Cambridge, Box 157, Level 5, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, United Kingdom
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32
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Nachtwey J, Spencer JV. HCMV IL-10 suppresses cytokine expression in monocytes through inhibition of nuclear factor-kappaB. Viral Immunol 2009; 21:477-82. [PMID: 19115937 DOI: 10.1089/vim.2008.0048] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Modulation of host immune responses is a common strategy for promoting virus persistence and avoiding clearance. Human cytomegalovirus (HCMV) is known to encode numerous immunomodulatory genes, including a homolog of the cytokine human interleukin-10 (hIL-10). While having limited sequence homology to hIL-10, cytomegalovirus IL-10 (cmvIL-10) shares many functional characteristics with the human cytokine and acts as a potent suppressor of the inflammatory immune response. The mechanism by which hIL-10 inhibits inflammatory cytokines involves a transcriptional block via inhibition of nuclear factor-kappaB (NF-kappaB) activity. To determine whether cmvIL-10 employs the same mechanism to inhibit cytokine production, the effect of cmvIL-10 on NF-kappaB signaling in monocytes was investigated. The results demonstrate that cmvIL-10 does inhibit NF-kappaB activation, as evidenced by reduced degradation of the NF-kappaB inhibitor IkappaB-alpha, and decreased transcription of the NF-kappaB-responsive genes tumor necrosis factor-alpha (TNF-alpha) and IL-1beta. These studies confirm that cmvIL-10 mediates cytokine suppression by blocking NF-kappaB transcriptional activity in human monocytes.
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Affiliation(s)
- James Nachtwey
- Department of Biology, University of San Francisco, San Francisco, California 94117, USA
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33
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Yurochko AD. Human cytomegalovirus modulation of signal transduction. Curr Top Microbiol Immunol 2008; 325:205-20. [PMID: 18637508 DOI: 10.1007/978-3-540-77349-8_12] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An upregulation of cellular signaling pathways is observed in multiple cell types upon human cytomegalovirus (HCMV) infection, suggesting that a global feature of HCMV infection is the activation of the host cell. HCMV initiates and maintains cellular signaling through a multitiered process that is dependent on a series of events: (1) the viral glycoprotein ligand interacts with its cognate receptor, (2) cellular enzymes and viral tegument proteins present in the incoming virion are released and (3) a variety of viral gene products are expressed. Viral-mediated cellular modification has differential outcomes depending on the cell type infected. In permissive cell types, such as diploid fibroblasts, the upregulation of cellular signaling pathways following infection can initiate the viral gene cascade and promote the efficient transcription of multiple viral gene classes. In other cell types, such as endothelial cells and monocytes/macrophages, the upregulation of cellular pathways initiates functional host changes that allow viral spread to multiple organ systems. Together, the modification of signaling processes appears to be part of a thematic strategy deployed by the virus to direct the required functional changes in target cells that ultimately promote viral survival and persistence in the host.
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Affiliation(s)
- A D Yurochko
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, 1501 Kings Highway Shreveport, LA 71130-3932, USA.
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Wei L, Kwang J, Wang J, Shi L, Yang B, Li Y, Liu J. Porcine circovirus type 2 induces the activation of nuclear factor kappa B by IkappaBalpha degradation. Virology 2008; 378:177-84. [PMID: 18561971 DOI: 10.1016/j.virol.2008.05.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 05/14/2008] [Indexed: 11/28/2022]
Abstract
The transcription factor NF-kappaB is commonly activated upon virus infection and a key player in the induction and regulation of the host immune response. The present study demonstrated for the first time that porcine circovirus type 2 (PCV2), which is the primary causative agent of an emerging swine disease, postweaning multisystemic wasting syndrome, can activate NF-kappaB in PCV2-infected PK15 cells. In PCV2-infected cells, NF-kappaB was activated concomitantly with viral replication, which was characterized by increased DNA binding activity, translocation of NF-kappaB p65 from the cytoplasm to the nucleus, as well as degradation and phosphorylation of IkappaBalpha protein. We further demonstrated PCV2-induced activation of NF-kappaB and colocalization of p65 nuclear translocation with virus replication in cultured cells. Treatment of cells with CAPE, a selective inhibitor of NF-kappaB activation, reduced virus protein expression and progeny production followed by decreasing PCV2-induced apoptotic caspase activity, indicating the involvement of this transcription factor in induction of cell death. Taken together, these data suggest that NF-kappaB activation is important for PCV2 replication and contributes to virus-mediated changes in host cells. The results presented here provide a basis for understanding molecular mechanism of PCV2 infection.
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Affiliation(s)
- Li Wei
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Municipal Academy of Agriculture and Forestry Sciences, No.9 Shuguang Garden Central Road, Haidian District, Beijing 100097, People's Republic of China
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Jaskoll T, Abichaker G, Sedghizadeh PP, Bringas P, Melnick M. Cytomegalovirus induces abnormal chondrogenesis and osteogenesis during embryonic mandibular development. BMC DEVELOPMENTAL BIOLOGY 2008; 8:33. [PMID: 18371224 PMCID: PMC2330031 DOI: 10.1186/1471-213x-8-33] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Accepted: 03/27/2008] [Indexed: 11/10/2022]
Abstract
Background Human clinical studies and mouse models clearly demonstrate that cytomegalovirus (CMV) disrupts normal organ and tissue development. Although CMV is one of the most common causes of major birth defects in humans, little is presently known about the mechanism(s) underlying CMV-induced congenital malformations. Our prior studies have demonstrated that CMV infection of first branchial arch derivatives (salivary glands and teeth) induced severely abnormal phenotypes and that CMV has a particular tropism for neural crest-derived mesenchyme (NCM). Since early embryos are barely susceptible to CMV infection, and the extant evidence suggests that the differentiation program needs to be well underway for embryonic tissues to be susceptible to viral infection and viral-induced pathology, the aim of this study was to determine if first branchial arch NCM cells are susceptible to mCMV infection prior to differentiation of NCM derivatives. Results E11 mouse mandibular processes (MANs) were infected with mouse CMV (mCMV) for up to 16 days in vitro. mCMV infection of undifferentiated embryonic mouse MANs induced micrognathia consequent to decreased Meckel's cartilage chondrogenesis and mandibular osteogenesis. Specifically, mCMV infection resulted in aberrant stromal cellularity, a smaller, misshapen Meckel's cartilage, and mandibular bone and condylar dysmorphogenesis. Analysis of viral distribution indicates that mCMV primarily infects NCM cells and derivatives. Initial localization studies indicate that mCMV infection changed the cell-specific expression of FN, NF-κB2, RelA, RelB, and Shh and Smad7 proteins. Conclusion Our results indicate that mCMV dysregulation of key signaling pathways in primarily NCM cells and their derivatives severely disrupts mandibular morphogenesis and skeletogenesis. The pathogenesis appears to be centered around the canonical and noncanonical NF-κB pathways, and there is unusual juxtaposition of abnormal stromal cells and surrounding matrix. Moreover, since it is critically important that signaling molecules are expressed in appropriate cell populations during development, the aberrant localization of components of relevant signaling pathways may reveal the pathogenic mechanism underlying mandibular malformations.
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Affiliation(s)
- Tina Jaskoll
- Laboratory for Developmental Genetics, USC, Los Angeles, CA, USA.
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NF-kappaB-mediated activation of the chemokine CCL22 by the product of the human cytomegalovirus gene UL144 escapes regulation by viral IE86. J Virol 2008; 82:4250-6. [PMID: 18287226 DOI: 10.1128/jvi.02156-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The product of the human cytomegalovirus (HCMV) gene UL144, expressed at early times postinfection, is located in the UL/b' region of the viral genome and is related to members of the tumor necrosis factor receptor superfamily, but it does not bind tumor necrosis factor superfamily ligands. However, UL144 does activate NF-kappaB, resulting in NF-kappaB-mediated activation of the cellular chemokine CCL22. Consistent with this finding, isolates of HCMV lacking the UL/b' region show no such activation of CCL22. Recently, it has been suggested that activation of NF-kappaB is repressed by the product of the viral gene IE86: IE86 appears to block NF-kappaB binding to DNA but not nuclear translocation of NF-kappaB. Intriguingly, IE86 is detectable throughout an infection with the virus, so how UL144 is able to activate NF-kappaB in the presence of continued IE86 expression is unclear. Here we show that although IE86 does repress the UL144-mediated activation of a synthetic NF-kappaB promoter, it is unable to block UL144-mediated activation of the CCL22 promoter, and this lack of responsiveness to IE86 appears to be regulated by binding of the CREB transcription factor.
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Jaskoll T, Abichaker G, Jangaard N, Bringas P, Melnick M. Cytomegalovirus inhibition of embryonic mouse tooth development: a model of the human amelogenesis imperfecta phenocopy. Arch Oral Biol 2008; 53:405-15. [PMID: 18201685 DOI: 10.1016/j.archoralbio.2007.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 10/29/2007] [Accepted: 11/28/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Cytomegalovirus (CMV) is one of the most common causes of major birth defects in humans. Of the approximately 8400 children born each year in the U.S. with CMV-induced birth defects, more than 1/3 of these children exhibit hypoplasia and hypocalcification of tooth enamel. Our objective was to initiate the investigation of the pathogenesis of CMV-induced tooth defects. DESIGN Mouse Cap stage mandibular first molars were infected with mouse CMV (mCMV) in vitro in a chemically-defined organ culture system and analysed utilising histological and immunolocalisation methodologies. The antiviral, acyclovir, was used to inhibit mCMV replication and comparisons made between mCMV-infected and acyclovir-treated, mCMV-infected teeth. RESULTS Active infection of Cap stage molars for up to 15 days in vitro results in smaller, developmentally-delayed and dysmorphic molars characterised by shallow, broad and misshapen cusps, infected and affected dental papilla mesenchyme, poorly differentiated odontoblasts and ameloblasts, and no dentin matrix. Initial protein localisation studies suggest that the pathogenesis is mediated through NF-kappaB signaling and that there appears to be an unusual interaction between abnormal mesenchymal cells and surrounding matrix. Rescue with acyclovir indicates that mCMV replication is necessary to initiate and sustain progressive tooth dysmorphogenesis. CONCLUSIONS Our results indicate that mCMV-induced changes in signaling pathways severely delays, but does not completely interrupt, tooth morphogenesis. Importantly, our results demonstrate that this well-defined embryonic mouse organ culture system can be utilised to delineate the molecular mechanism underlying the CMV-induced tooth defects that characterise the amelogenesis imperfecta phenocopy seen in many CMV-infected children.
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Affiliation(s)
- Tina Jaskoll
- Laboratory for Developmental Genetics, University of Southern California, Los Angeles, CA 90089-0641, USA.
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Transcriptome analysis of NF-kappaB- and phosphatidylinositol 3-kinase-regulated genes in human cytomegalovirus-infected monocytes. J Virol 2007; 82:1040-6. [PMID: 18003728 DOI: 10.1128/jvi.00864-07] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Human cytomegalovirus induces a proinflammatory monocyte following infection, and we have evidence that NF-kappaB and phosphatidylinositol 3-kinase [PI(3)K] are key mediators in this early activation. To begin to address how these signaling pathways are responsible for the rapid activation of infected monocytes, we examined the role that these pathways played in the transcriptome of infected monocytes. Global transcriptional profiling using cDNA microarrays revealed that a significant number of genes, including inflammatory genes, were regulated in an NF-kappaB- and/or PI(3)K-dependent manner, identifying the NF-kappaB and PI(3)K pathways as key cellular control points in the conversion of monocytes to an activated proinflammatory state following HCMV infection.
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Smith MS, Bivins-Smith ER, Tilley AM, Bentz GL, Chan G, Minard J, Yurochko AD. Roles of phosphatidylinositol 3-kinase and NF-kappaB in human cytomegalovirus-mediated monocyte diapedesis and adhesion: strategy for viral persistence. J Virol 2007; 81:7683-94. [PMID: 17507481 PMCID: PMC1933358 DOI: 10.1128/jvi.02839-06] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Infected peripheral blood monocytes are proposed to play a key role in the hematogenous dissemination of human cytomegalovirus (HCMV) to tissues, a critical step in the establishment of HCMV persistence and the development of HCMV-associated diseases. We recently provided evidence for a unique strategy involved in viral dissemination: HCMV infection of primary human monocytes promotes their transendothelial migration and differentiation into proinflammatory macrophages permissive for the replication of the original input virus. To decipher the mechanism of hematogenous spread, we focused on the viral dysregulation of early cellular processes involved in transendothelial migration. Here, we present evidence that both phosphatidylinositol 3-kinase [PI(3)K] and NF-kappaB activities were crucial for the HCMV induction of monocyte motility and firm adhesion to endothelial cells. We found that the beta(1) integrins, the beta(2) integrins, intracellular adhesion molecule 1 (ICAM-1), and ICAM-3 were upregulated following HCMV infection and that they played a key role in the firm adhesion of infected monocytes to the endothelium. The viral regulation of adhesion molecule expression is complex, with PI(3)K and NF-kappaB affecting the expression of each adhesion molecule at different stages of the expression cascade. Our data demonstrate key roles for PI(3)K and NF-kappaB signaling in the HCMV-induced cellular changes in monocytes and identify the biological rationale for the activation of these pathways in infected monocytes, which together suggest a mechanism for how HCMV promotes viral spread to and persistence within host organs.
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Affiliation(s)
- M Shane Smith
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
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Caposio P, Luganini A, Hahn G, Landolfo S, Gribaudo G. Activation of the virus-induced IKK/NF-kappaB signalling axis is critical for the replication of human cytomegalovirus in quiescent cells. Cell Microbiol 2007; 9:2040-54. [PMID: 17419715 DOI: 10.1111/j.1462-5822.2007.00936.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Activation of the IKK/NF-kappaB signalling pathway is a hallmark of human cytomegalovirus (HCMV) infection. However, its role in regulating major immediate-early promoter (MIEP)-dependent transcription and HCMV replication remains controversial. This study uses a combination of genetic approaches to investigate the effects of cell culture conditions on the importance of virus-induced NF-kappaB activation during the infection of endothelial cells or fibroblasts. Adenoviral-mediated expression of a dominant-negative mutant of IKK2 kinase (dnIKK2) in human umbilical vein endothelial cells resulted in a strong reduction of IkappaBalpha degradation and NF-kappaB activation following infection with an HCMV clinical isolate. Viral replication was impaired in dnIKK2-expressing cells that were growth-arrested before infection, but not in replicating cells. The inhibitory effect of dnIKK2 was independent from the virus strain and the cell type used, because replication of the laboratory AD169 strain was impaired as well in dnIKK2-expressing quiescent fibroblasts. Moreover, progressive disruption of NF-kappaB response elements within the MIEP in recombinant HCMV viruses derived from the clinical isolate prevented their replication in quiescent cells but not in actively growing cells. These results demonstrate an essential role of virus-induced IKK/NF-kappaB activity to trigger both viral IE gene expression and productive replication in quiescent cells.
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Affiliation(s)
- Patrizia Caposio
- Department of Public Health and Microbiology, University of Torino, Via Santena, 9-10126 Torino, Italy
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41
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Nogalski MT, Podduturi JP, DeMeritt IB, Milford LE, Yurochko AD. The human cytomegalovirus virion possesses an activated casein kinase II that allows for the rapid phosphorylation of the inhibitor of NF-kappaB, IkappaBalpha. J Virol 2007; 81:5305-14. [PMID: 17344282 PMCID: PMC1900216 DOI: 10.1128/jvi.02382-06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We documented that the NF-kappaB signaling pathway was rapidly induced following human cytomegalovirus (HCMV) infection of human fibroblasts and that this induced NF-kappaB activity promoted efficient transactivation of the major immediate-early promoter (MIEP). Previously, we showed that the major HCMV envelope glycoproteins, gB and gH, initiated this NF-kappaB signaling event. However, we also hypothesized that there were additional mechanisms utilized by the virus to rapidly upregulate NF-kappaB. In this light, we specifically hypothesized that the HCMV virion contained IkappaBalpha kinase activity, allowing for direct phosphorylation of IkappaBalpha following virion entry into infected cells. In vitro kinase assays performed on purified HCMV virion extract identified bona fide IkappaBalpha kinase activity in the virion. The enzyme responsible for this kinase activity was identified as casein kinase II (CKII), a cellular serine-threonine protein kinase. CKII activity was necessary for efficient transactivation of the MIEP and IE gene expression. CKII is generally considered to be a constitutively active kinase. We suggest that this molecular characteristic of CKII represents the biologic rationale for the viral capture and utilization of this kinase early after infection. The packaging of CKII into the HCMV virion identifies that diverse molecular mechanisms are utilized by HCMV for rapid NF-kappaB activation. We propose that HCMV possesses multiple pathways to increase NF-kappaB activity to ensure that the correct temporal regulation of NF-kappaB occurs following infection and that sufficient threshold levels of NF-kappaB are reached in the diverse array of cells, including monocytes and endothelial cells, infected in vivo.
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Affiliation(s)
- Maciej T Nogalski
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
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Montag C, Wagner J, Gruska I, Hagemeier C. Human cytomegalovirus blocks tumor necrosis factor alpha- and interleukin-1beta-mediated NF-kappaB signaling. J Virol 2006; 80:11686-98. [PMID: 17005669 PMCID: PMC1642604 DOI: 10.1128/jvi.01168-06] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Accepted: 09/12/2006] [Indexed: 12/14/2022] Open
Abstract
NF-kappaB plays an important role in the early cellular response to pathogens by activating genes involved in inflammation, immune response, and cell proliferation and survival. NF-kappaB is also utilized by many viral pathogens, like human cytomegalovirus (HCMV), to activate their own gene expression programs, reflecting intricate roles for NF-kappaB in both antiviral defense mechanisms and viral physiology. Here we show that the NF-kappaB signaling pathway stimulated by proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta) becomes inhibited in HCMV-infected cells. The block to NF-kappaB signaling is first noticeable during the early phase of infection but is fully established only at later times. Biochemical and genetic evidence demonstrates that the viral inhibition of proinflammatory signaling by distinct cytokines occurs upstream of the convergence point of NF-kappaB-activating pathways, i.e., the IkappaB kinase complex, and that it is mediated via different mechanisms. Consistent with this, we further show that an HCMV variant that has lost the ability to downregulate TNF-alpha-induced NF-kappaB signaling also fails to downregulate surface expression of TNF receptor 1, thereby mechanistically linking the inhibition of TNF-alpha-induced NF-kappaB signaling by HCMV to TNF receptor targeting. Our data support a model whereby HCMV inhibits cytokine-induced NF-kappaB signaling at later times during infection, and we suggest that this contributes to the inhibition of the cell's antiviral defense program.
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Affiliation(s)
- Christina Montag
- Laboratory of Molecular Biology, Children's Hospital, Charité-CCM, Ziegelstrasse 5-9, Humboldt University Berlin, D-10098 Berlin, Germany
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Gustems M, Borst E, Benedict CA, Pérez C, Messerle M, Ghazal P, Angulo A. Regulation of the transcription and replication cycle of human cytomegalovirus is insensitive to genetic elimination of the cognate NF-kappaB binding sites in the enhancer. J Virol 2006; 80:9899-904. [PMID: 16973595 PMCID: PMC1617225 DOI: 10.1128/jvi.00640-06] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The role of NF-kappaB in regulating human cytomegalovirus (HCMV) replication and gene transcription remains controversial. Multiple, functional NF-kappaB response elements exist in the major immediate-early promoter (MIEP) enhancer of HCMV, suggesting a possible requirement for this transcription factor in lytic viral replication. Here we demonstrate by generating and analyzing HCMVs with alterations in the MIEP-enhancer that, although this region is essential for HCMV growth, none of the four NF-kappaB response elements contained within the enhancer are required for MIE gene expression or HCMV replication in multiple cell types. These data reveal the robustness of the regulatory network controlling the MIEP enhancer.
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Affiliation(s)
- Montse Gustems
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, C/ Villarroel 170, Barcelona 08036, Spain
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Caposio P, Musso T, Luganini A, Inoue H, Gariglio M, Landolfo S, Gribaudo G. Targeting the NF-kappaB pathway through pharmacological inhibition of IKK2 prevents human cytomegalovirus replication and virus-induced inflammatory response in infected endothelial cells. Antiviral Res 2006; 73:175-84. [PMID: 17070604 DOI: 10.1016/j.antiviral.2006.10.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 09/20/2006] [Accepted: 10/03/2006] [Indexed: 12/22/2022]
Abstract
Endothelial cells are important reservoirs for human cytomegalovirus (HCMV) replication, dissemination and persistence. HCMV infection of endothelial cells has been associated with a proinflammatory response characterized by an increased expression of chemokines and adhesion molecules and modulation of angiogenesis. Many of the host proinflammatory genes augmented in HCMV-infected endothelial cells are regulated, at least in part, by the NF-kappaB pathway. HCMV is a potent activator of NF-kappaB through the IKK-IkappaB signaling axis. To explore whether inhibition of HCMV-induced NF-kappaB activation may interfere with the onset of virus-associated inflammatory response, we measured the effects of the specific IKK2 inhibitor AS602868 on the expression of a panel of proinflammatory genes in HUVEC cells infected with a clinical isolate. Treatment of infected HUVEC with AS602868 was shown to impair HCMV-induced NF-kappaB activity, IE gene expression, viral replication and to prevent HCMV-induced upregulation of ICAM-1, IL-8, RANTES, IP-10, I-TAC and COX-2 gene expression. Consistent with these results, HCMV-mediated upregulation of another NF-kappaB-dependent gene, the plasminogen inhibitor type-1, a regulatory factor of endothelial proliferation and angiogenesis, was abrogated by AS602868. These results suggest that inhibition of HCMV-induced IKK-NF-kappaB activation may be of interest to limit the virus-induced inflammatory response of infected endothelial cells.
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Affiliation(s)
- Patrizia Caposio
- Department of Public Health and Microbiology, University of Torino, Via Santena, 9, 10126 Torino, Italy
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Cook CH, Trgovcich J, Zimmerman PD, Zhang Y, Sedmak DD. Lipopolysaccharide, tumor necrosis factor alpha, or interleukin-1beta triggers reactivation of latent cytomegalovirus in immunocompetent mice. J Virol 2006; 80:9151-8. [PMID: 16940526 PMCID: PMC1563908 DOI: 10.1128/jvi.00216-06] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We have previously shown that cytomegalovirus (CMV) can reactivate in lungs of nonimmunosuppressed patients during critical illness. Our recent work has shown that polymicrobial bacterial sepsis can trigger reactivation of latent murine CMV (MCMV). We hypothesize that MCMV reactivation following bacterial sepsis may be caused by inflammatory mediators. To test this hypothesis, BALB/c mice latently infected with Smith strain MCMV received sublethal intraperitoneal doses of lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), or saline. Lung tissue homogenates were evaluated for viral reactivation 3 weeks after mediator injection. Because LPS is known to signal via Toll-like receptor 4 (TLR-4) in mice, further studies blocking this signaling mechanism were performed using monoclonal MTS510. Finally, mice were tested with intravenous TNF-alpha to determine whether this would cause reactivation. All mice receiving sublethal intraperitoneal doses of LPS, TNF-alpha, or IL-1beta had pulmonary reactivation of latent MCMV 3 weeks following injection, and LPS caused MCMV reactivation with kinetics similar to those for sepsis. When TLR-4 signaling was blocked, exogenous LPS did not reactivate latent MCMV. Intravenous TNF-alpha administration at near-lethal doses did not reactivate MCMV. Exogenous intraperitoneal LPS, TNF-alpha, and IL-1beta are all capable of reactivating CMV from latency in lungs of previously healthy mice. LPS reactivation of MCMV appears dependent on TLR-4 signaling. Interestingly, intravenous TNF-alpha did not trigger reactivation, suggesting possible mechanistic differences that are discussed. We conclude that inflammatory disease states besides sepsis may be capable of reactivating CMV from latency.
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Affiliation(s)
- Charles H Cook
- Department of Surgery, The Ohio State University, 410 West Tenth Ave., Columbus, OH 43210, USA
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Bentz GL, Jarquin-Pardo M, Chan G, Smith MS, Sinzger C, Yurochko AD. Human cytomegalovirus (HCMV) infection of endothelial cells promotes naive monocyte extravasation and transfer of productive virus to enhance hematogenous dissemination of HCMV. J Virol 2006; 80:11539-55. [PMID: 16987970 PMCID: PMC1642592 DOI: 10.1128/jvi.01016-06] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) pathogenesis is dependent on the hematogenous spread of the virus to host tissue. While data suggest that infected monocytes are required for viral dissemination from the blood to the host organs, infected endothelial cells are also thought to contribute to this key step in viral pathogenesis. We show here that HCMV infection of endothelial cells increased the recruitment and transendothelial migration of monocytes. Infection of endothelial cells promoted the increased surface expression of cell adhesion molecules (intercellular cell adhesion molecule 1, vascular cell adhesion molecule 1, E-selectin, and platelet endothelial cell adhesion molecule 1), which were necessary for the recruitment of naïve monocytes to the apical surface of the endothelium and for the migration of these monocytes through the endothelial cell layer. As a mechanism to account for the increased monocyte migration, we showed that HCMV infection of endothelial cells increased the permeability of the endothelium. The cellular changes contributing to the increased permeability and increased naïve monocyte transendothelial migration include the disruption of actin stress fiber formation and the decreased expression of lateral junction proteins (occludin and vascular endothelial cadherin). Finally, we showed that the migrating monocytes were productively infected with the virus, documenting that the virus was transferred to the migrating monocyte during passage through the lateral junctions. Together, our results provide evidence for an active role of the infected endothelium in HCMV dissemination and pathogenesis.
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Affiliation(s)
- Gretchen L Bentz
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
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Melnick M, Mocarski ES, Abichaker G, Huang J, Jaskoll T. Cytomegalovirus-induced embryopathology: mouse submandibular salivary gland epithelial-mesenchymal ontogeny as a model. BMC DEVELOPMENTAL BIOLOGY 2006; 6:42. [PMID: 16959038 PMCID: PMC1601957 DOI: 10.1186/1471-213x-6-42] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Accepted: 09/07/2006] [Indexed: 01/21/2023]
Abstract
BACKGROUND Human studies suggest, and mouse models clearly demonstrate, that cytomegalovirus (CMV) is dysmorphic to early organ and tissue development. CMV has a particular tropism for embryonic salivary gland and other head mesenchyme. CMV has evolved to co-opt cell signaling networks so to optimize replication and survival, to the detriment of infected tissues. It has been postulated that mesenchymal infection is the critical step in disrupting organogenesis. If so, organogenesis dependent on epithelial-mesenchymal interactions would be particularly vulnerable. In this study, we chose to model the vulnerability by investigating the cell and molecular pathogenesis of CMV infected mouse embryonic submandibular salivary glands (SMGs). RESULTS We infected E15 SMG explants with mouse CMV (mCMV). Active infection for up to 12 days in vitro results in a remarkable cell and molecular pathology characterized by atypical ductal epithelial hyperplasia, apparent epitheliomesenchymal transformation, oncocytic-like stromal metaplasia, beta-catenin nuclear localization, and upregulation of Nfkb2, Relb, Il6, Stat3, and Cox2. Rescue with an antiviral nucleoside analogue indicates that mCMV replication is necessary to initiate and maintain SMG dysmorphogenesis. CONCLUSION mCMV infection of embryonic mouse explants results in dysplasia, metaplasia, and, possibly, anaplasia. The molecular pathogenesis appears to center around the activation of canonical and, perhaps more importantly, noncanonical NFkappaB. Further, COX-2 and IL-6 are important downstream effectors of embryopathology. At the cellular level, there appears to be a consequential interplay between the transformed SMG cells and the surrounding extracellular matrix, resulting in the nuclear translocation of beta-catenin. From these studies, a tentative framework has emerged within which additional studies may be planned and performed.
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Affiliation(s)
- Michael Melnick
- Laboratory for Developmental Genetics, University of Southern California, Los Angeles, CA 90089-0641, USA
| | - Edward S Mocarski
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305-5124, USA
| | - George Abichaker
- Laboratory for Developmental Genetics, University of Southern California, Los Angeles, CA 90089-0641, USA
| | - Jing Huang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305-5124, USA
| | - Tina Jaskoll
- Laboratory for Developmental Genetics, University of Southern California, Los Angeles, CA 90089-0641, USA
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Zhang Z, Evers DL, McCarville JF, Dantonel JC, Huong SM, Huang ES. Evidence that the human cytomegalovirus IE2-86 protein binds mdm2 and facilitates mdm2 degradation. J Virol 2006; 80:3833-43. [PMID: 16571800 PMCID: PMC1440454 DOI: 10.1128/jvi.80.8.3833-3843.2006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Levels of the p53 tumor suppressor protein are increased in human cytomegalovirus (HCMV)-infected cells and may be important for HCMV pathogenesis. In normal cells p53 levels are kept low due to an autoregulatory feedback loop where p53 activates the transcription of mdm2 and mdm2 binds and ubiquitinates p53, targeting p53 for proteasomal degradation. Here we report that, in contrast to uninfected cells, mdm2 was undetectable upon treatment of infected fibroblasts with the proteasome inhibitor MG132. Cellular depletion of mdm2 was reproducible in p53-null cells transfected with the HCMV IE2-86 protein, but not with IE172, independently of the endogenous mdm2 promoter. IE2-86 also prevented the emergence of presumably ubiquitinated species of p53. The regions of IE2-86 important for mdm2 depletion were those containing the sequences corresponding to the putative zinc finger and C-terminal acidic motifs. mdm2 and IE2-86 coimmunoprecipitated in transfected and infected cell lysates and in a cell-free system. IE2-86 blocked mdm2's p53-independent transactivation of the cyclin A promoter in transient-transfection experiments. Pulse-chase experiments revealed that IE2-86 but not IE1-72 or several loss-of-function IE2-86 mutants increased the half-life of p53 and reduced the half-life of mdm2. Short interfering RNA-mediated depletion of IE2-86 restored the ability of HCMV-infected cells to accumulate mdm2 in response to proteasome inhibition. Taken together, the data suggest that specific interactions between IE2-86 and mdm2 cause proteasome-independent degradation of mdm2 and that this may be important for the accumulation of p53 in HCMV-infected cells.
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Affiliation(s)
- Zhigang Zhang
- CB #7295, Lineberger Comprehensive Cancer Center, Rm. 32-026, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7295, USA
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