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Cimato G, Zhou X, Brune W, Frascaroli G. Human cytomegalovirus glycoprotein variants governing viral tropism and syncytium formation in epithelial cells and macrophages. J Virol 2024:e0029324. [PMID: 38837351 DOI: 10.1128/jvi.00293-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 05/02/2024] [Indexed: 06/07/2024] Open
Abstract
Human cytomegalovirus (HCMV) displays a broad cell tropism, and the infection of biologically relevant cells such as epithelial, endothelial, and hematopoietic cells supports viral transmission, systemic spread, and pathogenesis in the human host. HCMV strains differ in their ability to infect and replicate in these cell types, but the genetic basis of these differences has remained incompletely understood. In this study, we investigated HCMV strain VR1814, which is highly infectious for epithelial cells and macrophages and induces cell-cell fusion in both cell types. A VR1814-derived bacterial artificial chromosome (BAC) clone, FIX-BAC, was generated many years ago but has fallen out of favor because of its modest infectivity. By sequence comparison and genetic engineering of FIX, we demonstrate that the high infectivity of VR1814 and its ability to induce syncytium formation in epithelial cells and macrophages depends on VR1814-specific variants of the envelope glycoproteins gB, UL128, and UL130. We also show that UL130-neutralizing antibodies inhibit syncytium formation, and a FIX-specific mutation in UL130 is responsible for its low infectivity by reducing the amount of the pentameric glycoprotein complex in viral particles. Moreover, we found that a VR1814-specific mutation in US28 further increases viral infectivity in macrophages, possibly by promoting lytic rather than latent infection of these cells. Our findings show that variants of gB and the pentameric complex are major determinants of infectivity and syncytium formation in epithelial cells and macrophages. Furthermore, the VR1814-adjusted FIX strains can serve as valuable tools to study HCMV infection of myeloid cells.IMPORTANCEHuman cytomegalovirus (HCMV) is a major cause of morbidity and mortality in transplant patients and the leading cause of congenital infections. HCMV infects various cell types, including epithelial cells and macrophages, and some strains induce the fusion of neighboring cells, leading to the formation of large multinucleated cells called syncytia. This process may limit the exposure of the virus to host immune factors and affect pathogenicity. However, the reason why some HCMV strains exhibit a broader cell tropism and why some induce cell fusion more than others is not well understood. We compared two closely related HCMV strains and provided evidence that small differences in viral envelope glycoproteins can massively increase or decrease the virus infectivity and its ability to induce syncytium formation. The results of the study suggest that natural strain variations may influence HCMV infection and pathogenesis in humans.
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Affiliation(s)
| | - Xuan Zhou
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Wolfram Brune
- Leibniz Institute of Virology (LIV), Hamburg, Germany
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Herbein G. Cellular Transformation by Human Cytomegalovirus. Cancers (Basel) 2024; 16:1970. [PMID: 38893091 PMCID: PMC11171319 DOI: 10.3390/cancers16111970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 05/13/2024] [Accepted: 05/17/2024] [Indexed: 06/21/2024] Open
Abstract
Epstein-Barr virus (EBV), Kaposi sarcoma human virus (KSHV), human papillomavirus (HPV), hepatitis B and C viruses (HBV, HCV), human T-lymphotropic virus-1 (HTLV-1), and Merkel cell polyomavirus (MCPyV) are the seven human oncoviruses reported so far. While traditionally viewed as a benign virus causing mild symptoms in healthy individuals, human cytomegalovirus (HCMV) has been recently implicated in the pathogenesis of various cancers, spanning a wide range of tissue types and malignancies. This perspective article defines the biological criteria that characterize the oncogenic role of HCMV and based on new findings underlines a critical role for HCMV in cellular transformation and modeling the tumor microenvironment as already reported for the other human oncoviruses.
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Affiliation(s)
- Georges Herbein
- Department Pathogens & Inflammation-EPILAB EA4266, University of Franche-Comté (UFC), 25000 Besançon, France;
- Department of Virology, CHU Besançon, 25000 Besançon, France
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3
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Sabourirad S, Dimitriadis E, Mantamadiotis T. Viruses exploit growth factor mechanisms to achieve augmented pathogenicity and promote tumorigenesis. Arch Microbiol 2024; 206:193. [PMID: 38526562 PMCID: PMC10963461 DOI: 10.1007/s00203-024-03855-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/13/2024] [Accepted: 01/20/2024] [Indexed: 03/26/2024]
Abstract
Cellular homeostasis is regulated by growth factors (GFs) which orchestrate various cellular processes including proliferation, survival, differentiation, motility, inflammation and angiogenesis. Dysregulation of GFs in microbial infections and malignancies have been reported previously. Viral pathogens exemplify the exploitation of host cell GFs and their signalling pathways contributing to viral entry, virulence, and evasion of anti-viral immune responses. Viruses can also perturb cellular metabolism and the cell cycle by manipulation of GF signaling. In some cases, this disturbance may promote oncogenesis. Viral pathogens can encode viral GF homologues and induce the endogenous biosynthesis of GFs and their corresponding receptors or manipulate their activity to infect the host cells. Close investigation of how viral strategies exploit and regulate GFs, a will shed light on how to improve anti-viral therapy and cancer treatment. In this review, we discuss and provide insights on how various viral pathogens exploit different GFs to promote viral survival and oncogenic transformation, and how this knowledge can be leveraged toward the design of more efficient therapeutics or novel drug delivery systems in the treatment of both viral infections and malignancies.
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Affiliation(s)
- Sarvenaz Sabourirad
- Department of Obstetrics and Gynaecology, The University of Melbourne, Parkville, VIC, Australia.
| | - Evdokia Dimitriadis
- Department of Obstetrics and Gynaecology, The University of Melbourne, Parkville, VIC, Australia
- Gynaecology Research Centre, Royal Women's Hospital, Parkville, VIC, Australia
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Theo Mantamadiotis
- Department of Surgery RMH, The University of Melbourne, Parkville, Australia
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Australia
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4
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Chesnokova LS, Mosher BS, Fulkerson HL, Nam HW, Shakya AK, Yurochko AD. Distinct early role of PTEN regulation during HCMV infection of monocytes. Proc Natl Acad Sci U S A 2024; 121:e2312290121. [PMID: 38483999 PMCID: PMC10962971 DOI: 10.1073/pnas.2312290121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 12/01/2023] [Indexed: 03/19/2024] Open
Abstract
Human cytomegalovirus (HCMV) infection of monocytes is essential for viral dissemination and persistence. We previously identified that HCMV entry/internalization and subsequent productive infection of this clinically relevant cell type is distinct when compared to other infected cells. We showed that internalization and productive infection required activation of epidermal growth factor receptor (EGFR) and integrin/c-Src, via binding of viral glycoprotein B to EGFR, and the pentamer complex to β1/β3 integrins. To understand how virus attachment drives entry, we compared infection of monocytes with viruses containing the pentamer vs. those without the pentamer and then used a phosphoproteomic screen to identify potential phosphorylated proteins that influence HCMV entry and trafficking. The screen revealed that the most prominent pentamer-biased phosphorylated protein was the lipid- and protein-phosphatase phosphatase and tensin homolog (PTEN). PTEN knockdown with siRNA or PTEN inhibition with a PTEN inhibitor decreased pentamer-mediated HCMV entry, without affecting trimer-mediated entry. Inhibition of PTEN activity affected lipid metabolism and interfered with the onset of the endocytic processes required for HCMV entry. PTEN inactivation was sufficient to rescue pentamer-null HCMV from lysosomal degradation. We next examined dephosphorylation of a PTEN substrate Rab7, a regulator of endosomal maturation. Inhibition of PTEN activity prevented dephosphorylation of Rab7. Phosphorylated Rab7, in turn, blocked early endosome to late endosome maturation and promoted nuclear localization of the virus and productive infection.
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Affiliation(s)
- Liudmila S. Chesnokova
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
- Center for Applied Immunology and Pathological Processes, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
| | - Bailey S. Mosher
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
- Center for Applied Immunology and Pathological Processes, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
| | - Heather L. Fulkerson
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
- Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
| | - Hyung W. Nam
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
| | - Akhalesh K. Shakya
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
| | - Andrew D. Yurochko
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
- Center for Applied Immunology and Pathological Processes, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
- Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
- Feist-Weller Cancer Center, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA 71103, Shreveport, LA71103
- Center for Excellence in Arthritis and Rheumatology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
- Center of Excellence for Emerging Viral Threats, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA71103
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Gerna G, Lilleri D, Fornara C, d'Angelo P, Baldanti F. Relationship of human cytomegalovirus-infected endothelial cells and circulating leukocytes in the pathogenesis of disseminated human cytomegalovirus infection: A narrative review. Rev Med Virol 2024; 34:e2496. [PMID: 38282408 DOI: 10.1002/rmv.2496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 10/12/2023] [Accepted: 11/26/2023] [Indexed: 01/30/2024]
Abstract
Among the leucocyte subpopulations circulating in peripheral blood of immune-compromised patients with disseminated Human cytomegalovirus (HCMV) infection, polymorphonuclear leuckocytes (PMNL) and M/M may carry infectious virus. While only in PMNL early HCMV replicative events do occur, monocytes are susceptible to complete virus replication when they enter human organs, where as macrophages become a site of active complete virus replication. In vivo leucocytes and endothelial cells interact continuously, as suggested by several in vitro experimental findings showing the bidirectional HCMV transmission from leucocytes to and from endothelial cells with the critical aid of adhesion molecules. Recently, the neutralising antibody response in sera from subjects with primary HCMV infection was reported to be much higher and earlier than in human embryonic lung fibroblasts (HELF) cells when measured in endothelial cells and epithelial cells, where virus entry is mediated mostly by the pentamer complex gH/gL/pUL128/pUL130/pUL131, whereas it was much lower and delayed when determined in HELF, where virus entry is mediated mostly by the trimer complex gH/gL/gO. Thus, these results suggested that products of UL128L were the molecules primary responsible for the differential neutralising antibody response. This conclusion was confirmed by a series of polyclonal and monoclonal antibodies directed to the components of pUL128L. Very recently, based on two sets of experiments including inhibition and immunoblotting assays, the pentamer complex/trimer complex ratio has been finally identified as the main factor of the neutralising antibody response. This ratio may change with the virus suspension producer and target cell system as well as number of cell culture passages.
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Affiliation(s)
- Giuseppe Gerna
- Centre for Inherited Cardiovascular Diseases, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Daniele Lilleri
- Microbiology and Virology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Chiara Fornara
- Laboratory Medicine Service, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| | - Piera d'Angelo
- Microbiology and Virology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Fausto Baldanti
- Microbiology and Virology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy
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6
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Narayanan KK, Amaya M, Tsang N, Yin R, Jays A, Broder CC, Shukla D, Procko E. Sequence basis for selectivity of ephrin-B2 ligand for Eph receptors and pathogenic henipavirus G glycoproteins. J Virol 2023; 97:e0062123. [PMID: 37931130 PMCID: PMC10688352 DOI: 10.1128/jvi.00621-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 09/13/2023] [Indexed: 11/08/2023] Open
Abstract
IMPORTANCE Ephrin-B2 (EFNB2) is a ligand for six Eph receptors in humans and regulates multiple cell developmental and signaling processes. It also functions as the cell entry receptor for Nipah virus and Hendra virus, zoonotic viruses that can cause respiratory and/or neurological symptoms in humans with high mortality. Here, we investigate the sequence basis of EFNB2 specificity for binding the Nipah virus attachment G glycoprotein over Eph receptors. We then use this information to engineer EFNB2 as a soluble decoy receptor that specifically binds the attachment glycoproteins of the Nipah virus and other related henipaviruses to neutralize infection. These findings further mechanistic understanding of protein selectivity and may facilitate the development of diagnostics or therapeutics against henipavirus infection.
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Affiliation(s)
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
| | - Natalie Tsang
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
| | - Randy Yin
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Alka Jays
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois, USA
- Cancer Center at Illinois, University of Illinois, Urbana, Illinois, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
- Cancer Center at Illinois, University of Illinois, Urbana, Illinois, USA
- Cyrus Biotechnology, Seattle, Washington, USA
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7
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Zehner M, Alt M, Ashurov A, Goldsmith JA, Spies R, Weiler N, Lerma J, Gieselmann L, Stöhr D, Gruell H, Schultz EP, Kreer C, Schlachter L, Janicki H, Laib Sampaio K, Stegmann C, Nemetchek MD, Dähling S, Ullrich L, Dittmer U, Witzke O, Koch M, Ryckman BJ, Lotfi R, McLellan JS, Krawczyk A, Sinzger C, Klein F. Single-cell analysis of memory B cells from top neutralizers reveals multiple sites of vulnerability within HCMV Trimer and Pentamer. Immunity 2023; 56:2602-2620.e10. [PMID: 37967532 DOI: 10.1016/j.immuni.2023.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/02/2023] [Accepted: 10/18/2023] [Indexed: 11/17/2023]
Abstract
Human cytomegalovirus (HCMV) can cause severe diseases in fetuses, newborns, and immunocompromised individuals. Currently, no vaccines are approved, and treatment options are limited. Here, we analyzed the human B cell response of four HCMV top neutralizers from a cohort of 9,000 individuals. By single-cell analyses of memory B cells targeting the pentameric and trimeric HCMV surface complexes, we identified vulnerable sites on the shared gH/gL subunits as well as complex-specific subunits UL128/130/131A and gO. Using high-resolution cryogenic electron microscopy, we revealed the structural basis of the neutralization mechanisms of antibodies targeting various binding sites. Moreover, we identified highly potent antibodies that neutralized a broad spectrum of HCMV strains, including primary clinical isolates, that outperform known antibodies used in clinical trials. Our study provides a deep understanding of the mechanisms of HCMV neutralization and identifies promising antibody candidates to prevent and treat HCMV infection.
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Affiliation(s)
- Matthias Zehner
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany.
| | - Mira Alt
- Department of Infectious Diseases, West German Centre of Infectious Diseases, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany
| | - Artem Ashurov
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Jory A Goldsmith
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Rebecca Spies
- Institute for Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Nina Weiler
- Institute for Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Justin Lerma
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Lutz Gieselmann
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; German Center for Infection Research, Partner Site Bonn-Cologne, 50931 Cologne, Germany
| | - Dagmar Stöhr
- Institute for Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Henning Gruell
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Eric P Schultz
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, USA
| | - Christoph Kreer
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Linda Schlachter
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Hanna Janicki
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | | | - Cora Stegmann
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, USA
| | - Michelle D Nemetchek
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, USA
| | - Sabrina Dähling
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Leon Ullrich
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Ulf Dittmer
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany
| | - Oliver Witzke
- Department of Infectious Diseases, West German Centre of Infectious Diseases, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany
| | - Manuel Koch
- Institute for Dental Research and Oral Musculoskeletal Biology, Center for Biochemistry, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Brent J Ryckman
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, USA
| | - Ramin Lotfi
- Institute for Transfusion Medicine, Ulm University Medical Center, 89081 Ulm, Germany
| | - Jason S McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Adalbert Krawczyk
- Department of Infectious Diseases, West German Centre of Infectious Diseases, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany; Institute for Virology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany
| | - Christian Sinzger
- Institute for Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Florian Klein
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; German Center for Infection Research, Partner Site Bonn-Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University Hospital of Cologne, 50931 Cologne, Germany.
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O'Brien BS, Mokry RL, Schumacher ML, Rosas-Rogers S, Terhune SS, Ebert AD. Neutralizing antibodies with neurotropic factor treatment maintain neurodevelopmental gene expression upon exposure to human cytomegalovirus. J Virol 2023; 97:e0069623. [PMID: 37796129 PMCID: PMC10653813 DOI: 10.1128/jvi.00696-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/23/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Human cytomegalovirus (HCMV) infection is the leading cause of non-heritable birth defects worldwide. HCMV readily infects the early progenitor cell population of the developing brain, and we have found that infection leads to significantly downregulated expression of key neurodevelopmental transcripts. Currently, there are no approved therapies to prevent or mitigate the effects of congenital HCMV infection. Therefore, we used human-induced pluripotent stem cell-derived organoids and neural progenitor cells to elucidate the glycoproteins and receptors used in the viral entry process and whether antibody neutralization was sufficient to block viral entry and prevent disruption of neurodevelopmental gene expression. We found that blocking viral entry alone was insufficient to maintain the expression of key neurodevelopmental genes, but neutralization combined with neurotrophic factor treatment provided robust protection. Together, these studies offer novel insight into mechanisms of HCMV infection in neural tissues, which may aid future therapeutic development.
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Affiliation(s)
- Benjamin S. O'Brien
- Department of Cell Biology, Neurobiology, and Anatomy, The Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Rebekah L. Mokry
- Department of Microbiology and Immunology, The Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Megan L. Schumacher
- Department of Microbiology and Immunology, The Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Suzette Rosas-Rogers
- Department of Microbiology and Immunology, The Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Scott S. Terhune
- Department of Microbiology and Immunology, The Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Marquette University and Medical College of Wisconsin Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Allison D. Ebert
- Department of Cell Biology, Neurobiology, and Anatomy, The Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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9
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Dunn DM, Pack LJ, Munger JC. Raf1 promotes successful Human Cytomegalovirus replication and is regulated by AMPK-mediated phosphorylation during infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.26.550702. [PMID: 37546879 PMCID: PMC10402018 DOI: 10.1101/2023.07.26.550702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Raf1 is a key player in growth factor receptor signaling, which has been linked to multiple viral infections, including Human Cytomegalovirus (HCMV) infection. Although HCMV remains latent in most individuals, it can cause acute infection in immunocompromised populations such as transplant recipients, neonates, and cancer patients. Current treatments are suboptimal, highlighting the need for novel treatments. Multiple points in the growth factor signaling pathway are important for HCMV infection, but the relationship between HCMV and Raf1, a component of the mitogen-activated protein kinase (MAPK) cascade, is not well understood. The AMP-activated protein kinase (AMPK) is a known regulator of Raf1, and AMPK activity is both induced by infection and important for HCMV replication. Our data indicate that HCMV infection induces AMPK-specific changes in Raf1 phosphorylation, including increasing phosphorylation at Raf1-Ser621, a known AMPK phospho-site, which results in increased binding to the 14-3-3 scaffolding protein, an important aspect of Raf1 activation. Inhibition of Raf1, either pharmacologically or via shRNA or CRISPR-mediated targeting, inhibits viral replication and spread in both fibroblasts and epithelial cells. Collectively, our data indicate that HCMV infection and AMPK activation modulate Raf1 activity, which are important for viral replication.
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Affiliation(s)
- Diana M. Dunn
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, NY, USA
| | - Ludia J. Pack
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, NY, USA
| | - Joshua C. Munger
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, NY, USA
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10
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Bošnjak B, Henze E, Lueder Y, Do KTH, Rezalotfi A, Čuvalo B, Ritter C, Schimrock A, Willenzon S, Georgiev H, Fritz L, Galla M, Wagner K, Messerle M, Förster R. MCK2-mediated MCMV infection of macrophages and virus dissemination to the salivary gland depends on MHC class I molecules. Cell Rep 2023; 42:112597. [PMID: 37289588 DOI: 10.1016/j.celrep.2023.112597] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 03/14/2023] [Accepted: 05/18/2023] [Indexed: 06/10/2023] Open
Abstract
Murine cytomegalovirus (MCMV) infection of macrophages relies on MCMV-encoded chemokine 2 (MCK2), while infection of fibroblasts occurs independently of MCK2. Recently, MCMV infection of both cell types was found to be dependent on cell-expressed neuropilin 1. Using a CRISPR screen, we now identify that MCK2-dependent infection requires MHC class Ia/β-2-microglobulin (B2m) expression. Further analyses reveal that macrophages expressing MHC class Ia haplotypes H-2b and H-2d, but not H-2k, are susceptible to MCK2-dependent infection with MCMV. The importance of MHC class I expression for MCK2-dependent primary infection and viral dissemination is highlighted by experiments with B2m-deficient mice, which lack surface expression of MHC class I molecules. In those mice, intranasally administered MCK2-proficient MCMV mimics infection patterns of MCK2-deficient MCMV in wild-type mice: it does not infect alveolar macrophages and subsequently fails to disseminate into the salivary glands. Together, these data provide essential knowledge for understanding MCMV-induced pathogenesis, tissue targeting, and virus dissemination.
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Affiliation(s)
- Berislav Bošnjak
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany.
| | - Elisa Henze
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Yvonne Lueder
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Kim Thi Hoang Do
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Alaleh Rezalotfi
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Berislav Čuvalo
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Christiane Ritter
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Anja Schimrock
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Stefanie Willenzon
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Hristo Georgiev
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Lea Fritz
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
| | - Melanie Galla
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - Karen Wagner
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Martin Messerle
- Institute of Virology, Hannover Medical School, Hannover, Germany; Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, 30625 Hannover, Germany
| | - Reinhold Förster
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany; Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, 30625 Hannover, Germany; German Centre for Infection Research (DZIF), Partner site Hannover, Hannover, Germany.
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11
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Narayanan KK, Amaya M, Tsang N, Yin R, Jays A, Broder CC, Shukla D, Procko E. The Sequence Basis for Selectivity of Ephrin-B2 Ligand for Eph Receptors and Pathogenic Henipavirus G Glycoproteins: Selective Ephrin-B2 Decoys for Nipah and Hendra Virus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.26.538420. [PMID: 37162958 PMCID: PMC10168364 DOI: 10.1101/2023.04.26.538420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Ephrin-B2 (EFNB2) is a ligand for six Eph receptors in humans and functions as a cell entry receptor for several henipaviruses including Nipah virus (NiV), a pathogenic zoonotic virus with pandemic potential. To understand the sequence basis of promiscuity for EFNB2 binding to the attachment glycoprotein of NiV (NiV-G) and Eph receptors, we performed deep mutagenesis on EFNB2 to identify mutations that enhance binding to NiV-G over EphB2, one of the highest affinity Eph receptors. The mutations highlight how different EFNB2 conformations are selected by NiV-G versus EphB2. Specificity mutations are enriched at the base of the G-H binding loop of EFNB2, especially surrounding a phenylalanine hinge upon which the G-H loop pivots, and at a phenylalanine hook that rotates away from the EFNB2 core to engage Eph receptors. One EFNB2 mutant, D62Q, possesses pan-specificity to the attachment glycoproteins of closely related henipaviruses and has markedly diminished binding to the six Eph receptors. However, EFNB2-D62Q has high residual binding to EphB3 and EphB4. A second deep mutational scan of EFNB2 identified combinatorial mutations to further enhance specificity to NiV-G. A triple mutant of soluble EFNB2, D62Q-Q130L-V167L, has minimal binding to Eph receptors but maintains binding, albeit reduced, to NiV-G. Soluble EFNB2 decoy receptors carrying the specificity mutations were potent neutralizers of chimeric henipaviruses. These findings demonstrate how specific residue changes at the shared binding interface of a promiscuous ligand (EFNB2) can influence selectivity for multiple receptors, and may also offer insight towards the development of henipavirus therapeutics and diagnostics.
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Affiliation(s)
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda MD, USA
| | - Natalie Tsang
- Department of Biochemistry, University of Illinois, Urbana IL, USA
| | - Randy Yin
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda MD, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda MD, USA
| | - Alka Jays
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda MD, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda MD, USA
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda MD, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL, USA
- Cancer Center at Illinois, University of Illinois, Urbana IL, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana IL, USA
- Cancer Center at Illinois, University of Illinois, Urbana IL, USA
- Cyrus Biotechnology, Seattle WA, USA
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12
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High-Risk Oncogenic Human Cytomegalovirus. Viruses 2022; 14:v14112462. [PMID: 36366560 PMCID: PMC9695668 DOI: 10.3390/v14112462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/04/2022] [Accepted: 11/05/2022] [Indexed: 11/09/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a herpesvirus that infects between 40% and 95% of the population worldwide, usually without symptoms. The host immune response keeps the virus in a latent stage, although HCMV can reactivate in an inflammatory context, which could result in sequential lytic/latent viral cycles during the lifetime and thereby participate in HCMV genomic diversity in humans. The high level of HCMV intra-host genomic variability could participate in the oncomodulatory role of HCMV where the virus will favor the development and spread of cancerous cells. Recently, an oncogenic role of HCMV has been highlighted in which the virus will directly transform primary cells; such HCMV strains are named high-risk (HR) HCMV strains. In light of these new findings, this review defines the criteria that characterize HR-HCMV strains and their molecular as well as the phenotypic impact on the infected cell and its tumor microenvironment.
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13
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Flomm FJ, Soh TK, Schneider C, Wedemann L, Britt HM, Thalassinos K, Pfitzner S, Reimer R, Grünewald K, Bosse JB. Intermittent bulk release of human cytomegalovirus. PLoS Pathog 2022; 18:e1010575. [PMID: 35925870 PMCID: PMC9352052 DOI: 10.1371/journal.ppat.1010575] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/06/2022] [Indexed: 01/24/2023] Open
Abstract
Human Cytomegalovirus (HCMV) can infect a variety of cell types by using virions of varying glycoprotein compositions. It is still unclear how this diversity is generated, but spatio-temporally separated envelopment and egress pathways might play a role. So far, one egress pathway has been described in which HCMV particles are individually enveloped into small vesicles and are subsequently exocytosed continuously. However, some studies have also found enveloped virus particles inside multivesicular structures but could not link them to productive egress or degradation pathways. We used a novel 3D-CLEM workflow allowing us to investigate these structures in HCMV morphogenesis and egress at high spatio-temporal resolution. We found that multiple envelopment events occurred at individual vesicles leading to multiviral bodies (MViBs), which subsequently traversed the cytoplasm to release virions as intermittent bulk pulses at the plasma membrane to form extracellular virus accumulations (EVAs). Our data support the existence of a novel bona fide HCMV egress pathway, which opens the gate to evaluate divergent egress pathways in generating virion diversity.
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Affiliation(s)
- Felix J. Flomm
- Centre for Structural Systems Biology, Hamburg, Germany
- Hannover Medical School, Institute of Virology, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
- Leibniz-Institute of Virology (LIV), Hamburg, Germany
| | - Timothy K. Soh
- Centre for Structural Systems Biology, Hamburg, Germany
- Hannover Medical School, Institute of Virology, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
- Leibniz-Institute of Virology (LIV), Hamburg, Germany
| | | | - Linda Wedemann
- Centre for Structural Systems Biology, Hamburg, Germany
- Hannover Medical School, Institute of Virology, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
- Leibniz-Institute of Virology (LIV), Hamburg, Germany
| | - Hannah M. Britt
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | | | | | - Kay Grünewald
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
- Leibniz-Institute of Virology (LIV), Hamburg, Germany
- University of Hamburg, Department of Chemistry, Hamburg, Germany
| | - Jens B. Bosse
- Centre for Structural Systems Biology, Hamburg, Germany
- Hannover Medical School, Institute of Virology, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
- Leibniz-Institute of Virology (LIV), Hamburg, Germany
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14
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Wines BD, Kurtovic L, Trist HM, Esparon S, Lopez E, Chappin K, Chan LJ, Mordant FL, Lee WS, Gherardin NA, Patel SK, Hartley GE, Pymm P, Cooney JP, Beeson JG, Godfrey DI, Burrell LM, van Zelm MC, Wheatley AK, Chung AW, Tham WH, Subbarao K, Kent SJ, Hogarth PM. Fc engineered ACE2-Fc is a potent multifunctional agent targeting SARS-CoV2. Front Immunol 2022; 13:889372. [PMID: 35967361 PMCID: PMC9369017 DOI: 10.3389/fimmu.2022.889372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/27/2022] [Indexed: 01/26/2023] Open
Abstract
Joining a function-enhanced Fc-portion of human IgG to the SARS-CoV-2 entry receptor ACE2 produces an antiviral decoy with strain transcending virus neutralizing activity. SARS-CoV-2 neutralization and Fc-effector functions of ACE2-Fc decoy proteins, formatted with or without the ACE2 collectrin domain, were optimized by Fc-modification. The different Fc-modifications resulted in distinct effects on neutralization and effector functions. H429Y, a point mutation outside the binding sites for FcγRs or complement caused non-covalent oligomerization of the ACE2-Fc decoy proteins, abrogated FcγR interaction and enhanced SARS-CoV-2 neutralization. Another Fc mutation, H429F did not improve virus neutralization but resulted in increased C5b-C9 fixation and transformed ACE2-Fc to a potent mediator of complement-dependent cytotoxicity (CDC) against SARS-CoV-2 spike (S) expressing cells. Furthermore, modification of the Fc-glycan enhanced cell activation via FcγRIIIa. These different immune profiles demonstrate the capacity of Fc-based agents to be engineered to optimize different mechanisms of protection for SARS-CoV-2 and potentially other viral pathogens.
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Affiliation(s)
- Bruce D. Wines
- Immune therapies Laboratory, Burnet Institute, Melbourne, VIC, Australia,Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia,Department of Clinical Pathology, The University of Melbourne, Parkville, VIC, Australia
| | - Liriye Kurtovic
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Halina M. Trist
- Immune therapies Laboratory, Burnet Institute, Melbourne, VIC, Australia
| | - Sandra Esparon
- Immune therapies Laboratory, Burnet Institute, Melbourne, VIC, Australia
| | - Ester Lopez
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Klasina Chappin
- Immune therapies Laboratory, Burnet Institute, Melbourne, VIC, Australia
| | - Li-Jin Chan
- Infectious Diseases and Immune Defence Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia,Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Francesca L. Mordant
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Wen Shi Lee
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Nicholas A. Gherardin
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Sheila K. Patel
- Department of Medicine, Austin Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Gemma E. Hartley
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Phillip Pymm
- Infectious Diseases and Immune Defence Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia,Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - James P. Cooney
- Infectious Diseases and Immune Defence Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia,Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - James G. Beeson
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia,Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia,Department of Microbiology, Monash University, Clayton VIC, Australia
| | - Dale I. Godfrey
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Louise M. Burrell
- Department of Medicine, Austin Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Menno C. van Zelm
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia,Department of Allergy, Immunology and Respiratory Medicine, Central Clinical School, Alfred Hospital, Melbourne, VIC, Australia
| | - Adam K. Wheatley
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia,Australian Research Council Centre for Excellence in Convergent Bio-Nano Science and Technology, The University of Melbourne, Melbourne, VIC, Australia
| | - Amy W. Chung
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Wai-Hong Tham
- Infectious Diseases and Immune Defence Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia,Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Kanta Subbarao
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia,World Health Organization (WHO) Collaborating Centre for Reference and Research on Influenza, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Stephen J. Kent
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia,Australian Research Council Centre for Excellence in Convergent Bio-Nano Science and Technology, The University of Melbourne, Melbourne, VIC, Australia,Melbourne Sexual Health Centre and Department of Infectious Diseases, Alfred Hospital and Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - P. Mark Hogarth
- Immune therapies Laboratory, Burnet Institute, Melbourne, VIC, Australia,Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia,*Correspondence: P. Mark Hogarth,
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15
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Braun B, Laib Sampaio K, Kuderna AK, Widmann M, Sinzger C. Viral and Cellular Factors Contributing to the Hematogenous Dissemination of Human Cytomegalovirus via Polymorphonuclear Leukocytes. Viruses 2022; 14:v14071561. [PMID: 35891541 PMCID: PMC9323586 DOI: 10.3390/v14071561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/12/2022] [Accepted: 07/16/2022] [Indexed: 02/06/2023] Open
Abstract
Polymorphonuclear leukocytes (PMNs) presumably transmit human cytomegalovirus (HCMV) between endothelial cells in blood vessels and thereby facilitate spread to peripheral organs. We aimed to identify viral components that contribute to PMN-mediated transmission and test the hypothesis that cellular adhesion molecules shield transmission sites from entry inhibitors. Stop codons were introduced into the genome of HCMV strain Merlin to delete pUL74 of the trimeric and pUL128 of the pentameric glycoprotein complex and the tegument proteins pp65 and pp71. Mutants were analyzed regarding virus uptake by PMNs and transfer of infection to endothelial cells. Cellular adhesion molecules were evaluated for their contribution to virus transmission using function-blocking antibodies, and hits were further analyzed regarding shielding against inhibitors of virus entry. The viral proteins pUL128, pp65, and pp71 were required for efficient PMN-mediated transmission, whereas pUL74 was dispensable. On the cellular side, the blocking of the αLβ2-integrin LFA-1 reduced virus transfer by 50% and allowed entry inhibitors to reduce it further by 30%. In conclusion, these data show that PMN-mediated transmission depends on the pentameric complex and an intact tegument and supports the idea of a virological synapse that promotes this dissemination mode both directly and via immune evasion.
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16
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Chin A, Liu J, Jardetzky T, Johnson DC, Vanarsdall A. Identification of functionally important domains of human cytomegalovirus gO that act after trimer binding to receptors. PLoS Pathog 2022; 18:e1010452. [PMID: 35452493 PMCID: PMC9032346 DOI: 10.1371/journal.ppat.1010452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 03/17/2022] [Indexed: 11/18/2022] Open
Abstract
Human cytomegalovirus (HCMV) entry involves trimer (gH/gL/gO) that interacts with PDGFRα in fibroblasts. Entry into epithelial and endothelial cells requires trimer, which binds unidentified receptors, and pentamer (gH/gL/UL128-131), which binds neuropilin-2. To identify functionally important domains in trimer, we screened an overlapping 20-mer gO peptide library and identified two sets of peptides: 19/20 (a.a. 235–267) and 32/33 (a.a. 404–436) that could block virus entry. Soluble trimer containing wild type gO blocked HCMV entry, whereas soluble trimers with the 19/20 or 32/33 sequences mutated did not block entry. Interestingly, the mutant trimers retained the capacity to bind to cellular receptors including PDGFRα. Peptide 19/20 and 32/33 sequences formed a lobe extending from the surface of gO and an adjacent concave structure, respectively. Neither of these sets of sequences contacted PDGFRα. Instead, our data support a model in which the 19/20 and 32/33 trimer sequences function downstream of receptor binding, e.g. trafficking of HCMV into endosomes or binding to gB for entry fusion. We also screened for peptides that bound antibodies (Abs) in human sera, observing that peptides 20 and 26 bound Abs. These peptides engendered neutralizing Abs (NAbs) after immunization of rabbits and could pull out NAbs from human sera. Peptides 20 and 26 sequences represent the first NAb epitopes identified in trimer. These studies describe two important surfaces on gO defined by: i) peptides 19/20 and 32/33, which apparently act downstream of receptor binding and ii) peptide 26 that interacts with PDGFRα. Both these surfaces are targets of NAbs. Human cytomegalovirus (HCMV) infects 80% of the world population, causing severe morbidity and mortality in transplant patients and can be transmitted to the developing fetus leading to severe neurological defects. The current anti-viral agents used to treat HCMV are not very effective as viruses can develop resistance and there is no licensed HCMV vaccine available. Recently, there has been intense interest in the HCMV envelope glycoproteins involved in entry as a component of vaccines. One glycoprotein complex, the gH/gL/gO trimer is especially intriguing as it is required for infection of extracellular virus in all cell types. Here, we identify domains in the trimer that have an essential function in entry downstream of receptor binding and are also epitopes recognized by naturally induced neutralizing antibodies. These results will have implications for advancing the efforts to develop novel HCMV therapeutics.
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Affiliation(s)
- Andrea Chin
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jing Liu
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Theodore Jardetzky
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - David C. Johnson
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Adam Vanarsdall
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
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17
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Tumors and Cytomegalovirus: An Intimate Interplay. Viruses 2022; 14:v14040812. [PMID: 35458542 PMCID: PMC9028007 DOI: 10.3390/v14040812] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/19/2022] [Accepted: 04/12/2022] [Indexed: 12/12/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a herpesvirus that alternates lytic and latent infection, infecting between 40 and 95% of the population worldwide, usually without symptoms. During its lytic cycle, HCMV can result in fever, asthenia, and, in some cases, can lead to severe symptoms such as hepatitis, pneumonitis, meningitis, retinitis, and severe cytomegalovirus disease, especially in immunocompromised individuals. Usually, the host immune response keeps the virus in a latent stage, although HCMV can reactivate in an inflammatory context, which could result in sequential lytic/latent viral cycles during the lifetime and thereby participate in the HCMV genomic diversity in humans and the high level of HCMV intrahost genomic variability. The oncomodulatory role of HCMV has been reported, where the virus will favor the development and spread of cancerous cells. Recently, an oncogenic role of HCMV has been highlighted in which the virus will directly transform primary cells and might therefore be defined as the eighth human oncovirus. In light of these new findings, it is critical to understand the role of the immune landscape, including the tumor microenvironment present in HCMV-harboring tumors. Finally, the oncomodulatory/oncogenic potential of HCMV could lead to the development of novel adapted therapeutic approaches against HCMV, especially since immunotherapy has revolutionized cancer therapeutic strategies and new therapeutic approaches are actively needed, particularly to fight tumors of poor prognosis.
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18
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Li J, Wellnitz S, Chi XS, Yue Y, Schmidt KA, Nguyen N, Chen W, Yurgelonis I, Rojas E, Liu Y, Loschko J, Pollozi E, Matsuka YV, Needle E, Vidunas E, Donald RGK, Moran J, Jansen KU, Dormitzer PR, Barry PA, Yang X. Horizontal transmission of cytomegalovirus in a rhesus model despite high-level, vaccine-elicited neutralizing antibody and T cell responses. J Infect Dis 2022; 226:585-594. [PMID: 35413121 PMCID: PMC10147388 DOI: 10.1093/infdis/jiac129] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 04/07/2022] [Indexed: 11/14/2022] Open
Abstract
The development of a vaccine to prevent congenital human cytomegalovirus (HCMV) disease is a public health priority. We tested rhesus CMV (RhCMV) prototypes of HCMV vaccine candidates in a seronegative macaque oral challenge model. Immunogens included a recombinant pentameric complex (PC; gH/gL/pUL128/pUL130/pUL131A), a postfusion gB ectodomain, and a DNA plasmid that encodes pp65-2. Immunization with QS21-adjuvanted PC alone or with the other immunogens elicited neutralizing titers comparable to those elicited by RhCMV infection. Similarly, immunization with all three immunogens elicited pp65-specific cytotoxic T cell responses comparable to those elicited by RhCMV infection. RhCMV readily infected immunized animals and was detected in saliva, blood and urine after challenge in quantities similar to those in placebo-immunized animals. If HCMV evades vaccine-elicited immunity in humans as RhCMV evaded immunity in macaques, a HCMV vaccine must elicit immunity superior to, or different from, that elicited by the prototype RhCMV vaccine to block horizontal transmission.
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Affiliation(s)
- Julia Li
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Sabine Wellnitz
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Xiaoyuan S Chi
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Yujuan Yue
- Center for Comparative Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Kimberli A Schmidt
- Center for Comparative Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Nancy Nguyen
- Center for Comparative Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Wei Chen
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Irina Yurgelonis
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Eduardo Rojas
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Yuhang Liu
- Groton Center for Chemistry, Pfizer Inc., Groton, CT 06340, USA
| | - Jakob Loschko
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Eneida Pollozi
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Yury V Matsuka
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Elie Needle
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Eugene Vidunas
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Robert G K Donald
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Justin Moran
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Kathrin U Jansen
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Philip R Dormitzer
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
| | - Peter A Barry
- Center for Comparative Medicine, University of California, Davis, Davis, CA 95616, USA.,Department of Pathology and Laboratory Medicine, University of California, Davis, Davis, CA 95616, USA.,California National Primate Research Center, University of California, Davis, Davis, CA 95616, USA
| | - Xinzhen Yang
- Vaccine Research and Development, Pfizer Inc., Pearl River, New York 10965, USA
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19
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Zou L, Shi C, Wang D, Cheng J, Wang Q, Wang L, Yang G. Long non-coding RNA-non-coding RNA activated by DNA damage inhibition suppresses hepatic stellate cell activation via microRNA-495-3p/sphingosine 1-phosphate receptor 3 axis. Bioengineered 2022; 13:6150-6162. [PMID: 35200103 PMCID: PMC8973981 DOI: 10.1080/21655979.2022.2037841] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Hepatic fibrosis is a damage repair response caused by multiple factors. A growing body of research suggests that long non-coding RNAs (lncRNAs) are involved in a wide range of biological processes, and thus regulate disease progression, including hepatic fibrosis. In this study, we investigated the mechanisms of the long non-coding RNA-non-coding RNA activated by DNA damage (NORAD) in modulating hepatic fibrosis development. Platelet-derived growth factor-BB (PDGF-BB) was used to activate LX-2 hepatic stellate cells (HSCs). The expression of NORAD and microRNA (miR)-495-3p was determined by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The effects of PDGF-BB on LX-2 cell viability, migration, invasion, and apoptosis were evaluated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), Transwell, flow cytometry, and Western blot assays. The activation of HSCs was further verified by examining the expression of the typical markers, alpha smooth muscle actin (α-SMA) and collagen I (Col1α1), using qRT-PCR and Western blot assays. StarBase and dual-luciferase reporter assays were used to assess the binding relationship between miR-495-3p and NORAD. The NORAD levels remarkably increased, whereas the miR-495-3p levels decreased, in PDGF-BB-treated LX-2 cells. miR-495-3p was a putative downstream target of NORAD. NORAD silencing played an anti-fibrotic role by targeting miR-495-3p; this was accomplished by hindering PDGF-BB-treated LX-2 cell viability, migration, and invasion, decreasing the levels of α-SMA and Col1α1, and promoting apoptosis. miR-495-3p protected against hepatic fibrosis by inhibiting sphingosine 1-phosphate receptor 3 (S1PR3) expression. In summary, NORAD silencing inhibited hepatic fibrosis by suppressing HSC activation via the miR-495-3p/S1PR3 axis.
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Affiliation(s)
- Lei Zou
- Department of Infectious Diseases, Yancheng Second People's Hospital, Yancheng, China
| | - Cuifen Shi
- Department of Gastroenterology, Yancheng Second People's Hospital, Yancheng, China
| | - Dawei Wang
- Department of Infectious Diseases, Yancheng Second People's Hospital, Yancheng, China
| | - Juan Cheng
- Department of Infectious Diseases, Yancheng Second People's Hospital, Yancheng, China
| | - Qi Wang
- Department of Infectious Diseases, Yancheng Second People's Hospital, Yancheng, China
| | - Lei Wang
- Department of Infectious Diseases, Yancheng Second People's Hospital, Yancheng, China
| | - Guoya Yang
- Department of Infectious Diseases, Yancheng Second People's Hospital, Yancheng, China
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20
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Tyl MD, Betsinger CN, Cristea IM. Virus-host protein interactions as footprints of human cytomegalovirus replication. Curr Opin Virol 2022; 52:135-147. [PMID: 34923282 PMCID: PMC8844139 DOI: 10.1016/j.coviro.2021.11.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 11/24/2021] [Indexed: 02/03/2023]
Abstract
Human cytomegalovirus (HCMV) is a pervasive β-herpesvirus that causes lifelong infection. The lytic replication cycle of HCMV is characterized by global organelle remodeling and dynamic virus-host interactions, both of which are necessary for productive HCMV replication. With the advent of new technologies for investigating protein-protein and protein-nucleic acid interactions, numerous critical interfaces between HCMV and host cells have been identified. Here, we review temporal and spatial virus-host interactions that support different stages of the HCMV replication cycle. Understanding how HCMV interacts with host cells during entry, replication, and assembly, as well as how it interfaces with host cell metabolism and immune responses promises to illuminate processes that underlie the biology of infection and the resulting pathologies.
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Affiliation(s)
- Matthew D. Tyl
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Cora N. Betsinger
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Ileana M. Cristea
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA,Corresponding author and lead contact: Ileana M. Cristea, 210 Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, Tel: 6092589417, Fax: 6092584575,
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21
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Cryo-Electron Microscopy Structure and Interactions of the Human Cytomegalovirus gHgLgO Trimer with Platelet-Derived Growth Factor Receptor Alpha. mBio 2021; 12:e0262521. [PMID: 34700375 PMCID: PMC8546573 DOI: 10.1128/mbio.02625-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a herpesvirus that produces disease in transplant patients and newborn children. Entry of HCMV into cells relies on gH/gL trimer (gHgLgO) and pentamer (gHgLUL128–131) complexes that bind cellular receptors. Here, we studied the structure and interactions of the HCMV trimer, formed by AD169 strain gH and gL and TR strain gO proteins, with the human platelet-derived growth factor receptor alpha (PDGFRα). Three trimer surfaces make extensive contacts with three PDGFRα N-terminal domains, causing PDGFRα to wrap around gO in a structure similar to a human hand, explaining the high-affinity interaction. gO is among the least conserved HCMV proteins, with 8 distinct genotypes. We observed high conservation of residues mediating gO-gL interactions but more extensive gO variability in the PDGFRα interface. Comparisons between our trimer structure and a previously determined structure composed of different subunit genotypes indicate that gO variability is accommodated by adjustments in the gO-PDGFRα interface. We identified two loops within gO that were disordered and apparently glycosylated, which could be deleted without disrupting PDGFRα binding. We also identified four gO residues that contact PDGFRα, which when mutated produced markedly reduced receptor binding. These residues fall within conserved contact sites of gO with PDGFRα and may represent key targets for anti-trimer neutralizing antibodies and HCMV vaccines. Finally, we observe that gO mutations distant from the gL interaction site impact trimer expression, suggesting that the intrinsic folding or stability of gO can impact the efficiency of trimer assembly.
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22
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Peptide Derivatives of Platelet-Derived Growth Factor Receptor Alpha Inhibit Cell-Associated Spread of Human Cytomegalovirus. Viruses 2021; 13:v13091780. [PMID: 34578361 PMCID: PMC8473290 DOI: 10.3390/v13091780] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/26/2021] [Accepted: 09/01/2021] [Indexed: 12/27/2022] Open
Abstract
Cell-free human cytomegalovirus (HCMV) can be inhibited by a soluble form of the cellular HCMV-receptor PDGFRα, resembling neutralization by antibodies. The cell-associated growth of recent HCMV isolates, however, is resistant against antibodies. We investigated whether PDGFRα-derivatives can inhibit this transmission mode. A protein containing the extracellular PDGFRα-domain and 40-mer peptides derived therefrom were tested regarding the inhibition of the cell-associated HCMV strain Merlin-pAL1502, hits were validated with recent isolates, and the most effective peptide was modified to increase its potency. The modified peptide was further analyzed regarding its mode of action on the virion level. While full-length PDGFRα failed to inhibit HCMV isolates, three peptides significantly reduced virus growth. A 30-mer version of the lead peptide (GD30) proved even more effective against the cell-free virus, and this effect was HCMV-specific and depended on the viral glycoprotein O. In cell-associated spread, GD30 reduced both the number of transferred particles and their penetration. This effect was reversible after peptide removal, which allowed the synchronized analysis of particle transfer, showing that two virions per hour were transferred to neighboring cells and one virion was sufficient for infection. In conclusion, PDGFRα-derived peptides are novel inhibitors of the cell-associated spread of HCMV and facilitate the investigation of this transmission mode.
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23
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Human Immunodeficiency Virus (HIV) and Human Cytomegalovirus (HCMV) Coinfection of Infant Tonsil Epithelium May Synergistically Promote both HIV-1 and HCMV Spread and Infection. J Virol 2021; 95:e0092121. [PMID: 34232730 DOI: 10.1128/jvi.00921-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1) and human cytomegalovirus (HCMV) may occur during pregnancy, labor, or breastfeeding. These viruses from amniotic fluid, cervicovaginal secretions, and breast milk may simultaneously interact with oropharyngeal and tonsil epithelia; however, the molecular mechanism of HIV-1 and HCMV cotransmission through the oral mucosa and its role in MTCT are poorly understood. To study the molecular mechanism of HIV-1 and HCMV MTCT via oral epithelium, we established polarized infant tonsil epithelial cells and polarized-oriented ex vivo tonsil tissue explants. Using these models, we showed that cell-free HIV-1 and its proteins gp120 and tat induce the disruption of tonsil epithelial tight junctions and increase paracellular permeability, which facilitates HCMV spread within the tonsil mucosa. Inhibition of HIV-1 gp120-induced upregulation of mitogen-activated protein kinase (MAPK) and NF-κB signaling in tonsil epithelial cells, reduces HCMV infection, indicating that HIV-1-activated MAPK and NF-κB signaling may play a critical role in HCMV infection of tonsil epithelium. HCMV infection of tonsil epithelial cells also leads to the disruption of tight junctions and increases paracellular permeability, facilitating HIV-1 paracellular spread into tonsil mucosa. HCMV-promoted paracellular spread of HIV-1 increases its accessibility to tonsil CD4 T lymphocytes, macrophages, and dendritic cells. HIV-1-enhanced HCMV paracellular spread and infection of epithelial cells subsequently leads to the spread of HCMV to tonsil macrophages and dendritic cells. Our findings revealed that HIV-1- and HCMV-induced disruption of infant tonsil epithelial tight junctions promotes MTCT of these viruses through tonsil mucosal epithelium, and therapeutic intervention for both HIV-1 and HCMV infection may substantially reduce their MTCT. IMPORTANCE Most HIV-1 and HCMV MTCT occurs in infancy, and the cotransmission of these viruses may occur via infant oropharyngeal and tonsil epithelia, which are the first biological barriers for viral pathogens. We have shown that HIV-1 and HCMV disrupt epithelial junctions, reducing the barrier functions of epithelia and thus allowing paracellular penetration of both viruses via mucosal epithelia. Subsequently, HCMV infects epithelial cells, macrophages, and dendritic cells, and HIV-1 infects CD4+ lymphocytes, macrophages, and dendritic cells. Infection of these cells in HCMV- and HIV-1-coinfected tonsil tissues is much higher than that by HCMV or HIV-1 infection alone, promoting their MTCT at its initial stages via infant oropharyngeal and tonsil epithelia.
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24
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Pavišić V, Mahmutefendić Lučin H, Blagojević Zagorac G, Lučin P. Arf GTPases Are Required for the Establishment of the Pre-Assembly Compartment in the Early Phase of Cytomegalovirus Infection. Life (Basel) 2021; 11:867. [PMID: 34440611 PMCID: PMC8399710 DOI: 10.3390/life11080867] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/31/2022] Open
Abstract
Shortly after entering the cells, cytomegaloviruses (CMVs) initiate massive reorganization of cellular endocytic and secretory pathways, which results in the forming of the cytoplasmic virion assembly compartment (AC). We have previously shown that the formation of AC in murine CMV- (MCMV) infected cells begins in the early phase of infection (at 4-6 hpi) with the pre-AC establishment. Pre-AC comprises membranes derived from the endosomal recycling compartment, early endosomes, and the trans-Golgi network, which is surrounded by fragmented Golgi cisterns. To explore the importance of Arf GTPases in the biogenesis of the pre-AC, we infected Balb 3T3 cells with MCMV and analyzed the expression and intracellular localization of Arf proteins in the early phases (up to 16 hpi) of infection and the development of pre-AC in cells with a knockdown of Arf protein expression by small interfering RNAs (siRNAs). Herein, we show that even in the early phase, MCMVs cause massive reorganization of the Arf system of the host cells and induce the over-recruitment of Arf proteins onto the membranes of pre-AC. Knockdown of Arf1, Arf3, Arf4, or Arf6 impaired the establishment of pre-AC. However, the knockdown of Arf1 and Arf6 also abolished the establishment of infection. Our study demonstrates that Arf GTPases are required for different steps of early cytomegalovirus infection, including the establishment of the pre-AC.
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Affiliation(s)
- Valentino Pavišić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
| | - Hana Mahmutefendić Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Gordana Blagojević Zagorac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Pero Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
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25
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Schultz EP, Yu Q, Stegmann C, Day LZ, Lanchy JM, Ryckman BJ. Mutagenesis of Human Cytomegalovirus Glycoprotein L Disproportionately Disrupts gH/gL/gO over gH/gL/pUL128-131. J Virol 2021; 95:e0061221. [PMID: 34132577 PMCID: PMC8354327 DOI: 10.1128/jvi.00612-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/04/2021] [Indexed: 01/14/2023] Open
Abstract
Cell-free and cell-to-cell spread of herpesviruses involves a core fusion apparatus comprised of the fusion protein glycoprotein B (gB) and the regulatory factor gH/gL. The human cytomegalovirus (HCMV) gH/gL/gO and gH/gL/pUL128-131 facilitate spread in different cell types. The gO and pUL128-131 components bind distinct receptors, but how the gH/gL portions of the complexes functionally compare is not understood. We previously characterized a panel of gL mutants by transient expression and showed that many were impaired for gH/gL-gB-dependent cell-cell fusion but were still able to form gH/gL/pUL128-131 and induce receptor interference. Here, the gL mutants were engineered into the HCMV BAC clones TB40/e-BAC4 (TB), TR, and Merlin (ME), which differ in their utilization of the two complexes for entry and spread. Several of the gL mutations disproportionately impacted gH/gL/gO-dependent entry and spread over gH/gL/pUL128-131 processes. The effects of some mutants could be explained by impaired gH/gL/gO assembly, but other mutants impacted gH/gL/gO function. Soluble gH/gL/gO containing the L201 mutant failed to block HCMV infection despite unimpaired binding to PDGFRα, indicating the existence of other important gH/gL/gO receptors. Another mutant (L139) enhanced the gH/gL/gO-dependent cell-free spread of TR, suggesting a "hyperactive" gH/gL/gO. Recently published crystallography and cryo-electron microscopy studies suggest structural conservation of the gH/gL underlying gH/gL/gO and gH/gL/pUL128-131. However, our data suggest important differences in the gH/gL of the two complexes and support a model in which gH/gL/gO can provide an activation signal for gB. IMPORTANCE The endemic betaherpesvirus HCMV circulates in human populations as a complex mixture of genetically distinct variants, establishes lifelong persistent infections, and causes significant disease in neonates and immunocompromised adults. This study capitalizes on our recent characterizations of three genetically distinct HCMV BAC clones to discern the functions of the envelope glycoprotein complexes gH/gL/gO and gH/gL/pUL128-13, which are promising vaccine targets that share the herpesvirus core fusion apparatus component, gH/gL. Mutations in the shared gL subunit disproportionally affected gH/gL/gO, demonstrating mechanistic differences between the two complexes, and may provide a basis for more refined evaluations of neutralizing antibodies.
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Affiliation(s)
- Eric P. Schultz
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana, USA
| | - Qin Yu
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Cora Stegmann
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Le Zhang Day
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
- Biochemistry and Biophysics Program, University of Montana, Missoula, Montana, USA
| | - Jean-Marc Lanchy
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Brent J. Ryckman
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana, USA
- Biochemistry and Biophysics Program, University of Montana, Missoula, Montana, USA
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26
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The Human Cytomegalovirus Protein UL116 Interacts with the Viral Endoplasmic-Reticulum-Resident Glycoprotein UL148 and Promotes the Incorporation of gH/gL Complexes into Virions. J Virol 2021; 95:e0220720. [PMID: 34011552 DOI: 10.1128/jvi.02207-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Heterodimers of glycoproteins H (gH) and L (gL) comprise a basal element of the viral membrane fusion machinery conserved across herpesviruses. In human cytomegalovirus (HCMV), the glycoprotein UL116 assembles onto gH at a position similar to that occupied by gL, forming a heterodimer that is incorporated into virions. Here, we show that UL116 promotes the expression of gH/gL complexes and is required for the efficient production of infectious cell-free virions. UL116-null mutants show a 10-fold defect in production of infectious cell-free virions from infected fibroblasts and epithelial cells. This defect is accompanied by reduced expression of two disulfide-linked gH/gL complexes that play crucial roles in viral entry: the heterotrimer of gH/gL with glycoprotein O (gO) and the pentameric complex of gH/gL with UL128, UL130, and UL131. Kifunensine, a mannosidase inhibitor that interferes with endoplasmic reticulum (ER)-associated degradation (ERAD) of terminally misfolded glycoproteins, restored levels of gH, gL, and gO in UL116-null-infected cells, indicating that constituents of HCMV gH complexes are unstable in the absence of UL116. Further, we find that gH/UL116 complexes are abundant in virions, since a major gH species not covalently linked to other glycoproteins, which has long been observed in the literature, is detected from wild-type but not UL116-null virions. Interestingly, UL116 coimmunoprecipitates with UL148, a viral ER-resident glycoprotein that attenuates ERAD of gO, and we observe elevated levels of UL116 in UL148-null virions. Collectively, our findings argue that UL116 is a chaperone for gH that supports the assembly, maturation, and incorporation of gH/gL complexes into virions. IMPORTANCE HCMV is a betaherpesvirus that causes dangerous opportunistic infections in immunocompromised patients as well as in the immune-naive fetus and preterm infants. The potential of the virus to enter new host cells is governed in large part by two alternative viral glycoprotein H (gH)/glycoprotein L (gL) complexes that play important roles in entry: gH/gL/gO and gH/gL/UL128-131. A recently identified virion gH complex, comprised of gH bound to UL116, adds a new layer of complexity to the mechanisms that contribute to HCMV infectivity. Here, we show that UL116 promotes the expression of gH/gL complexes and that UL116 interacts with the viral ER-resident glycoprotein UL148, a factor that supports the expression of gH/gL/gO. Overall, our results suggest that UL116 is a chaperone for gH. These findings have important implications for understanding HCMV cell tropism as well as for the development of vaccines against the virus.
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27
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Laib Sampaio K, Lutz C, Engels R, Stöhr D, Sinzger C. Selection of Human Cytomegalovirus Mutants with Resistance against PDGFRα-Derived Entry Inhibitors. Viruses 2021; 13:v13061094. [PMID: 34201364 PMCID: PMC8229732 DOI: 10.3390/v13061094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 12/25/2022] Open
Abstract
The human cytomegalovirus (HCMV) infects fibroblasts via an interaction of its envelope glycoprotein gO with the cellular platelet-derived growth factor receptor alpha (PDGFRα), and soluble derivatives of this receptor can inhibit viral entry. We aimed to select mutants with resistance against PDGFRα-Fc and the PDGFRα-derived peptides GT40 and IK40 to gain insight into the underlying mechanisms and determine the genetic barrier to resistance. An error-prone variant of strain AD169 was propagated in the presence of inhibitors, cell cultures were monitored weekly for signs of increased viral growth, and selected viruses were tested regarding their sensitivity to the inhibitor. Resistant virus was analyzed by DNA sequencing, candidate mutations were transferred into AD169 clone pHB5 by seamless mutagenesis, and reconstituted virus was again tested for loss of sensitivity by dose-response analyses. An S48Y mutation in gO was identified that conferred a three-fold loss of sensitivity against PDGFRα-Fc, a combination of mutations in gO, gH, gB and gN reduced sensitivity to GT40 by factor 4, and no loss of sensitivity occurred with IK40. The resistance-conferring mutations support the notion that PDGFRα-Fc and GT40 perturb the interaction of gO with its receptor, but the relatively weak effect indicates a high genetic barrier to resistance.
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28
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Braun B, Sinzger C. Transmission of cell-associated human cytomegalovirus isolates between various cell types using polymorphonuclear leukocytes as a vehicle. Med Microbiol Immunol 2021; 210:197-209. [PMID: 34091753 PMCID: PMC8286230 DOI: 10.1007/s00430-021-00713-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/15/2021] [Indexed: 12/25/2022]
Abstract
Polymorphonuclear leukocytes (PMNs) are regarded as vehicles for the hematogenous dissemination of human cytomegalovirus (HCMV). In cell culture, this concept has been validated with cell-free laboratory strains but not yet with clinical HCMV isolates that grow strictly cell-associated. We, therefore, aimed to evaluate whether PMNs can also transmit such isolates from initially infected fibroblasts to other cell types, which might further clarify the role of PMNs in HCMV dissemination and provide a model to search for potential inhibitors. PMNs, which have been isolated from HCMV-seronegative individuals, were added for 3 h to fibroblasts infected with recent cell-associated HCMV isolates, then removed and transferred to various recipient cell cultures. The transfer efficiency in the recipient cultures was evaluated by immunofluorescence staining of viral immediate early antigens. Soluble derivatives of the cellular HCMV entry receptor PDGFRα were analyzed for their potential to interfere with this transfer. All of five tested HCMV isolates could be transferred to fibroblasts, endothelial and epithelial cells with transfer rates ranging from 2 to 9%, and the transferred viruses could spread focally in these recipient cells within 1 week. The PDGFRα-derived peptides IK40 and GT40 reduced transfer by 40 and 70% when added during the uptake step. However, when added during the transfer step, only IK40 was effective, inhibiting transmission by 20% on endothelial cells and 50–60% on epithelial cells and fibroblasts. These findings further corroborate the assumption of cell-associated HCMV dissemination by PMNs and demonstrate that it is possible to inhibit this transmission mode.
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Affiliation(s)
- Berenike Braun
- Institute for Virology, Ulm University Medical Center, Ulm, Germany.
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29
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Lee BJ, Min CK, Hancock M, Streblow DN, Caposio P, Goodrum FD, Yurochko AD. Human Cytomegalovirus Host Interactions: EGFR and Host Cell Signaling Is a Point of Convergence Between Viral Infection and Functional Changes in Infected Cells. Front Microbiol 2021; 12:660901. [PMID: 34025614 PMCID: PMC8138183 DOI: 10.3389/fmicb.2021.660901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/07/2021] [Indexed: 12/22/2022] Open
Abstract
Viruses have evolved diverse strategies to manipulate cellular signaling pathways in order to promote infection and/or persistence. Human cytomegalovirus (HCMV) possesses a number of unique properties that allow the virus to alter cellular events required for infection of a diverse array of host cell types and long-term persistence. Of specific importance is infection of bone marrow derived and myeloid lineage cells, such as peripheral blood monocytes and CD34+ hematopoietic progenitor cells (HPCs) because of their essential role in dissemination of the virus and for the establishment of latency. Viral induced signaling through the Epidermal Growth Factor Receptor (EGFR) and other receptors such as integrins are key control points for viral-induced cellular changes and productive and latent infection in host organ systems. This review will explore the current understanding of HCMV strategies utilized to hijack cellular signaling pathways, such as EGFR, to promote the wide-spread dissemination and the classic life-long herpesvirus persistence.
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Affiliation(s)
- Byeong-Jae Lee
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States.,Center for Applied Immunology and Pathological Processes, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States.,Center of Excellence for Emerging Viral Threats, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States
| | - Chan-Ki Min
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States.,Center for Applied Immunology and Pathological Processes, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States.,Center of Excellence for Emerging Viral Threats, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States
| | - Meaghan Hancock
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, OR, United States
| | - Daniel N Streblow
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, OR, United States
| | - Patrizia Caposio
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, OR, United States
| | | | - Andrew D Yurochko
- Department of Microbiology & Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States.,Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States.,Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States.,Center of Excellence in Arthritis and Rheumatology, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, United States
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30
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Narayanan KK, Procko E. Deep Mutational Scanning of Viral Glycoproteins and Their Host Receptors. Front Mol Biosci 2021; 8:636660. [PMID: 33898517 PMCID: PMC8062978 DOI: 10.3389/fmolb.2021.636660] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
Deep mutational scanning or deep mutagenesis is a powerful tool for understanding the sequence diversity available to viruses for adaptation in a laboratory setting. It generally involves tracking an in vitro selection of protein sequence variants with deep sequencing to map mutational effects based on changes in sequence abundance. Coupled with any of a number of selection strategies, deep mutagenesis can explore the mutational diversity available to viral glycoproteins, which mediate critical roles in cell entry and are exposed to the humoral arm of the host immune response. Mutational landscapes of viral glycoproteins for host cell attachment and membrane fusion reveal extensive epistasis and potential escape mutations to neutralizing antibodies or other therapeutics, as well as aiding in the design of optimized immunogens for eliciting broadly protective immunity. While less explored, deep mutational scans of host receptors further assist in understanding virus-host protein interactions. Critical residues on the host receptors for engaging with viral spikes are readily identified and may help with structural modeling. Furthermore, mutations may be found for engineering soluble decoy receptors as neutralizing agents that specifically bind viral targets with tight affinity and limited potential for viral escape. By untangling the complexities of how sequence contributes to viral glycoprotein and host receptor interactions, deep mutational scanning is impacting ideas and strategies at multiple levels for combatting circulating and emergent virus strains.
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Affiliation(s)
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, United States
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31
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Weiler N, Paal C, Adams K, Calcaterra C, Fischer D, Stanton RJ, Stöhr D, Laib Sampaio K, Sinzger C. Role of Envelope Glycoprotein Complexes in Cell-Associated Spread of Human Cytomegalovirus. Viruses 2021; 13:v13040614. [PMID: 33918406 PMCID: PMC8066785 DOI: 10.3390/v13040614] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/26/2021] [Indexed: 12/15/2022] Open
Abstract
The role of viral envelope glycoproteins, particularly the accessory proteins of trimeric and pentameric gH/gL-complexes, in cell-associated spread of human cytomegalovirus (HCMV) is unclear. We aimed to investigate their contribution in the context of HCMV variants that grow in a strictly cell-associated manner. In the genome of Merlin pAL1502, the glycoproteins gB, gH, gL, gM, and gN were deleted by introducing stop codons, and the mutants were analyzed for viral growth. Merlin and recent HCMV isolates were compared by quantitative immunoblotting for expression of accessory proteins of the trimeric and pentameric gH/gL-complexes, gO and pUL128. Isolates were treated with siRNAs against gO and pUL128 and analyzed regarding focal growth and release of infectious virus. All five tested glycoproteins were essential for growth of Merlin pAL1502. Compared with this model virus, higher gO levels were measured in recent isolates of HCMV, and its knockdown decreased viral growth. Knockdown of pUL128 abrogated the strict cell-association and led to release of infectivity, which allowed cell-free transfer to epithelial cells where the virus grew again strictly cell-associated. We conclude that both trimer and pentamer contribute to cell-associated spread of recent clinical HCMV isolates and downregulation of pentamer can release infectious virus into the supernatant.
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Affiliation(s)
- Nina Weiler
- Institute for Virology, Ulm University Medical Center, 89089 Ulm, Germany; (N.W.); (C.P.); (K.A.); (C.C.); (D.F.); (D.S.); (K.L.S.)
| | - Caroline Paal
- Institute for Virology, Ulm University Medical Center, 89089 Ulm, Germany; (N.W.); (C.P.); (K.A.); (C.C.); (D.F.); (D.S.); (K.L.S.)
| | - Kerstin Adams
- Institute for Virology, Ulm University Medical Center, 89089 Ulm, Germany; (N.W.); (C.P.); (K.A.); (C.C.); (D.F.); (D.S.); (K.L.S.)
| | - Christopher Calcaterra
- Institute for Virology, Ulm University Medical Center, 89089 Ulm, Germany; (N.W.); (C.P.); (K.A.); (C.C.); (D.F.); (D.S.); (K.L.S.)
| | - Dina Fischer
- Institute for Virology, Ulm University Medical Center, 89089 Ulm, Germany; (N.W.); (C.P.); (K.A.); (C.C.); (D.F.); (D.S.); (K.L.S.)
| | - Richard James Stanton
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff CF14 4XN, UK;
| | - Dagmar Stöhr
- Institute for Virology, Ulm University Medical Center, 89089 Ulm, Germany; (N.W.); (C.P.); (K.A.); (C.C.); (D.F.); (D.S.); (K.L.S.)
| | - Kerstin Laib Sampaio
- Institute for Virology, Ulm University Medical Center, 89089 Ulm, Germany; (N.W.); (C.P.); (K.A.); (C.C.); (D.F.); (D.S.); (K.L.S.)
| | - Christian Sinzger
- Institute for Virology, Ulm University Medical Center, 89089 Ulm, Germany; (N.W.); (C.P.); (K.A.); (C.C.); (D.F.); (D.S.); (K.L.S.)
- Correspondence:
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Feldmann S, Grimm I, Stöhr D, Antonini C, Lischka P, Sinzger C, Stegmann C. Targeted mutagenesis on PDGFRα-Fc identifies amino acid modifications that allow efficient inhibition of HCMV infection while abolishing PDGF sequestration. PLoS Pathog 2021; 17:e1009471. [PMID: 33780515 PMCID: PMC8031885 DOI: 10.1371/journal.ppat.1009471] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 04/08/2021] [Accepted: 03/12/2021] [Indexed: 12/15/2022] Open
Abstract
Platelet-derived growth factor receptor alpha (PDGFRα) serves as an entry receptor for the human cytomegalovirus (HCMV), and soluble PDGFRα-Fc can neutralize HCMV at a half-maximal effective concentration (EC50) of about 10 ng/ml. While this indicates a potential for usage as an HCMV entry inhibitor PDGFRα-Fc can also bind the physiological ligands of PDGFRα (PDGFs), which likely interferes with the respective signaling pathways and represents a potential source of side effects. Therefore, we tested the hypothesis that interference with PDGF signaling can be prevented by mutations in PDGFRα-Fc or combinations thereof, without losing the inhibitory potential for HCMV. To this aim, a targeted mutagenesis approach was chosen. The mutations were quantitatively tested in biological assays for interference with PDGF-dependent signaling as well as inhibition of HCMV infection and biochemically for reduced affinity to PDGF-BB, facilitating quantification of PDGFRα-Fc selectivity for HCMV inhibition. Mutation of Ile 139 to Glu and Tyr 206 to Ser strongly reduced the affinity for PDGF-BB and hence interference with PDGF-dependent signaling. Inhibition of HCMV infection was less affected, thus increasing the selectivity by factor 4 and 8, respectively. Surprisingly, the combination of these mutations had an additive effect on binding of PDGF-BB but not on inhibition of HCMV, resulting in a synergistic 260fold increase of selectivity. In addition, a recently reported mutation, Val 242 to Lys, was included in the analysis. PDGFRα-Fc with this mutation was fully effective at blocking HCMV entry and had a drastically reduced affinity for PDGF-BB. Combining Val 242 to Lys with Ile 139 to Glu and/or Tyr 206 to Ser further reduced PDGF ligand binding beyond detection. In conclusion, this targeted mutagenesis approach identified combinations of mutations in PDGFRα-Fc that prevent interference with PDGF-BB but maintain inhibition of HCMV, which qualifies such mutants as candidates for the development of HCMV entry inhibitors.
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Affiliation(s)
- Svenja Feldmann
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
| | | | - Dagmar Stöhr
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
| | - Chiara Antonini
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Peter Lischka
- AiCuris Anti-infective Cures GmbH, Wuppertal, Germany
| | - Christian Sinzger
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
- * E-mail: (CSi); (CSt)
| | - Cora Stegmann
- Institute of Virology, Ulm University Medical Center, Ulm, Germany
- * E-mail: (CSi); (CSt)
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33
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Singh K, Hamilton ST, Shand AW, Hannan NJ, Rawlinson WD. Receptors in host pathogen interactions between human cytomegalovirus and the placenta during congenital infection. Rev Med Virol 2021; 31:e2233. [PMID: 33709529 DOI: 10.1002/rmv.2233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 02/26/2021] [Accepted: 02/26/2021] [Indexed: 11/09/2022]
Abstract
Cellular receptors in human cytomegalovirus (HCMV) mother to child transmission play an important role in congenital infection. Placental trophoblast cells are a significant cell type in placental development, placental functional processes, and in HCMV transmission. Different cells within the placental floating and chorionic villi present alternate receptors for HCMV cell entry. Syncytiotrophoblasts present neonatal Fc receptors that bind and transport circulating maternal immunoglobulin G across the placental interface which can also be bound to HCMV virions, facilitating viral entry into the placenta and foetal circulation. Cytotrophoblast express HCMV receptors including integrin-α1β1, integrin-αVβ3, epidermal growth factor receptor and platelet-derived growth factor receptor alpha. The latter interacts with HCMV glycoprotein-H, glycoprotein-L and glycoprotein-O (gH/gL/gO) trimers (predominantly in placental fibroblasts) and the gH/gL/pUL128, UL130-UL131A pentameric complex in other placental cell types. The pentameric complex allows viral tropism of placental trophoblasts, endothelial cells, epithelial cells, leukocytes and monocytes. This review outlines HCMV ligands and target receptor proteins in congenital HCMV infection.
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Affiliation(s)
- Krishneel Singh
- Serology and Virology Division, NSW Health Pathology, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Stuart T Hamilton
- Serology and Virology Division, NSW Health Pathology, Prince of Wales Hospital, Sydney, New South Wales, Australia.,School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Antonia W Shand
- School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,Children's Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Natalie J Hannan
- Therapeutics Discovery and Vascular Function in Pregnancy Group, Department of Obstetrics and Gynaecology, University of Melbourne, Victoria, Australia.,Mercy Perinatal, Mercy Hospital for Women Heidelberg, Victoria, Australia
| | - William D Rawlinson
- Serology and Virology Division, NSW Health Pathology, Prince of Wales Hospital, Sydney, New South Wales, Australia.,School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, New South Wales, Australia
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Kschonsak M, Rougé L, Arthur CP, Hoangdung H, Patel N, Kim I, Johnson MC, Kraft E, Rohou AL, Gill A, Martinez-Martin N, Payandeh J, Ciferri C. Structures of HCMV Trimer reveal the basis for receptor recognition and cell entry. Cell 2021; 184:1232-1244.e16. [PMID: 33626330 DOI: 10.1016/j.cell.2021.01.036] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/10/2021] [Accepted: 01/21/2021] [Indexed: 01/19/2023]
Abstract
Human cytomegalovirus (HCMV) infects the majority of the human population and represents the leading viral cause of congenital birth defects. HCMV utilizes the glycoproteins gHgLgO (Trimer) to bind to platelet-derived growth factor receptor alpha (PDGFRα) and transforming growth factor beta receptor 3 (TGFβR3) to gain entry into multiple cell types. This complex is targeted by potent neutralizing antibodies and represents an important candidate for therapeutics against HCMV. Here, we determine three cryogenic electron microscopy (cryo-EM) structures of the trimer and the details of its interactions with four binding partners: the receptor proteins PDGFRα and TGFβR3 as well as two broadly neutralizing antibodies. Trimer binding to PDGFRα and TGFβR3 is mutually exclusive, suggesting that they function as independent entry receptors. In addition, Trimer-PDGFRα interaction has an inhibitory effect on PDGFRα signaling. Our results provide a framework for understanding HCMV receptor engagement, neutralization, and the development of anti-viral strategies against HCMV.
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Affiliation(s)
- Marc Kschonsak
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
| | - Lionel Rougé
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | | | - Ho Hoangdung
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Nidhi Patel
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Ingrid Kim
- Department of Antibody Engineering, Genentech, South San Francisco, CA 94080, USA
| | - Matthew C Johnson
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Edward Kraft
- Department of BioMolecular Resources, Genentech, South San Francisco, CA 94080, USA
| | - Alexis L Rohou
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Avinash Gill
- Department of Antibody Engineering, Genentech, South San Francisco, CA 94080, USA
| | - Nadia Martinez-Martin
- Department of Microchemistry, Proteomics and Lipidomics Department, Genentech, South San Francisco, CA 94080, USA.
| | - Jian Payandeh
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA; Department of Antibody Engineering, Genentech, South San Francisco, CA 94080, USA.
| | - Claudio Ciferri
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
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35
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Jones IKA, Haese NN, Gatault P, Streblow ZJ, Andoh TF, Denton M, Streblow CE, Bonin K, Kreklywich CN, Burg JM, Orloff SL, Streblow DN. Rat Cytomegalovirus Virion-Associated Proteins R131 and R129 Are Necessary for Infection of Macrophages and Dendritic Cells. Pathogens 2020; 9:E963. [PMID: 33228102 PMCID: PMC7699341 DOI: 10.3390/pathogens9110963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/05/2020] [Accepted: 11/17/2020] [Indexed: 12/15/2022] Open
Abstract
Cytomegalovirus (CMV) establishes persistent, latent infection in hosts, causing diseases in immunocompromised patients, transplant recipients, and neonates. CMV infection modifies the host chemokine axis by modulating chemokine and chemokine receptor expression and by encoding putative chemokine and chemokine receptor homologues. The viral proteins have roles in cellular signaling, migration, and transformation, as well as viral dissemination, tropism, latency and reactivation. Herein, we review the contribution of CMV-encoded chemokines and chemokine receptors to these processes, and further elucidate the viral tropism role of rat CMV (RCMV) R129 and R131. These homologues of the human CMV (HCMV)-encoded chemokines UL128 and UL130 are of particular interest because of their dual role as chemokines and members of the pentameric entry complex, which is required for entry into cell types that are essential for viral transmission and dissemination. The contributions of UL128 and UL130 to acceleration of solid organ transplant chronic rejection are poorly understood, and are in need of an effective in vivo model system to elucidate the phenomenon. We demonstrated similar molecular entry requirements for R129 and R131 in the rat cells, as observed for HCMV, and provided evidence that R129 and R131 are part of the viral entry complex required for entry into macrophages, dendritic cells, and bone marrow cells.
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Affiliation(s)
- Iris K. A. Jones
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
| | - Nicole N. Haese
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
| | - Philippe Gatault
- Renal Transplant Unit, 10 Boulevard Tonnellé, University Hospital of Tours, 37032 Tours, France;
| | - Zachary J. Streblow
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
| | - Takeshi F. Andoh
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
- Department of Surgery, Oregon Health & Science University, Portland, OR 97239, USA; (J.M.B.); (S.L.O.)
| | - Michael Denton
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
| | - Cassilyn E. Streblow
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
| | - Kiley Bonin
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
| | - Craig N. Kreklywich
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
| | - Jennifer M. Burg
- Department of Surgery, Oregon Health & Science University, Portland, OR 97239, USA; (J.M.B.); (S.L.O.)
| | - Susan L. Orloff
- Department of Surgery, Oregon Health & Science University, Portland, OR 97239, USA; (J.M.B.); (S.L.O.)
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Daniel N. Streblow
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, Portland, OR 97239, USA; (I.K.A.J.); (N.N.H.); (Z.J.S.); (T.F.A.); (M.D.); (C.E.S.); (K.B.); (C.N.K.)
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Single-Point Mutations within the Coxsackie B Virus Receptor-Binding Site Promote Resistance against Soluble Virus Receptor Traps. J Virol 2020; 94:JVI.00952-20. [PMID: 32669334 PMCID: PMC7495374 DOI: 10.1128/jvi.00952-20] [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: 05/18/2020] [Accepted: 06/18/2020] [Indexed: 12/28/2022] Open
Abstract
Coxsackie B viruses (CVB) cause a wide spectrum of diseases, ranging from mild respiratory syndromes and hand, foot, and mouth disease to life-threatening conditions, such as pancreatitis, myocarditis, and encephalitis. Previously, we and others found that the soluble virus receptor trap sCAR-Fc strongly attenuates CVB3 infection in mice. In this study, we investigated whether treatment with sCAR-Fc results in development of resistance by CVB3. Two CVB3 strains (CVB3-H3 and CVB3 Nancy) were passaged in HeLa cells in the presence of sCAR-Fc. The CVB3-H3 strain did not develop resistance, whereas two populations of CVB3 Nancy mutants emerged, one with complete (CVB3M) and one with partial (CVB3K) resistance. DNA sequence alignment of the resistant virus variant CVB3M with CVB3 Nancy revealed an amino acid exchange from Asn(N) to Ser(S) at position 139 of the CVB3 capsid protein VP2 (N2139S), an amino acid predicted to be involved in the virus's interaction with its cognate receptor CAR. Insertion of the N2139S mutation into CVB3-H3 by site-directed mutagenesis promoted resistance of the engineered CVB3-H3N2139S to sCAR-Fc. Interestingly, development of resistance by CVB3-H3N2139S and the exemplarily investigated CVB3M-clone 2 (CVB3M2) against soluble CAR did not compromise the use of cellular CAR for viral infection. Infection of HeLa cells showed that sCAR-Fc resistance, however, negatively affected both virus stability and viral replication compared to that of the parental strains. These data demonstrate that during sCAR-Fc exposure, CVB3 can develop resistance against sCAR-Fc by single-amino-acid exchanges within the virus-receptor binding site, which, however, come at the expense of viral fitness.IMPORTANCE The emergence of resistant viruses is one of the most frequent obstacles preventing successful therapy of viral infections, representing a significant threat to human health. We investigated the emergence of resistant viruses during treatment with sCAR-Fc, a well-studied, highly effective antiviral molecule against CVB infections. Our data show the molecular aspects of resistant CVB3 mutants that arise during repetitive sCAR-Fc usage. However, drug resistance comes at the price of lower viral fitness. These results extend our knowledge of the development of resistance by coxsackieviruses and indicate potential limitations of antiviral therapy using soluble receptor molecules.
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Brait N, Stögerer T, Kalser J, Adler B, Kunz I, Benesch M, Kropff B, Mach M, Puchhammer-Stöckl E, Görzer I. Influence of Human Cytomegalovirus Glycoprotein O Polymorphism on the Inhibitory Effect of Soluble Forms of Trimer- and Pentamer-Specific Entry Receptors. J Virol 2020; 94:e00107-20. [PMID: 32350071 PMCID: PMC7343208 DOI: 10.1128/jvi.00107-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/21/2020] [Indexed: 01/24/2023] Open
Abstract
Human cytomegalovirus (HCMV) envelope glycoprotein complexes, gH/gL/gO trimer and gH/gL/UL128-131 pentamer, are important for cell-free HCMV entry. While soluble NRP2-Fc (sNRP2-Fc) interferes with epithelial/endothelial cell entry through UL128, soluble platelet-derived growth factor receptor α-Fc (sPDGFRα-Fc) interacts with gO, thereby inhibiting infection of all cell types. Since gO is the most variable subunit, we investigated the influence of gO polymorphism on the inhibitory capacities of sPDGFRα-Fc and sNRP2-Fc. Accordingly, gO genotype 1c (GT1c) sequence was fully or partially replaced by gO GT2b, GT3, and GT5 sequences in the bacterial artificial chromosome (BAC) TB40-BAC4-luc background (where luc is luciferase). All mutants were tested for fibroblast and epithelial cell infectivity, for virion content of gB, gH, and gO, and for infection inhibition by sPDGFRα-Fc and sNRP2-Fc. Full-length and partial gO GT swapping may increase epithelial-to-fibroblast ratios due to subtle alterations in fibroblast and/or epithelial infectivity but without substantial changes in gB and gH levels in mutant virions. All gO GT mutants except recombinant gO GT1c/3 displayed a nearly complete inhibition at 1.25 μg/ml sPDGFRα-Fc on epithelial cells (98% versus 91%), and all experienced complete inhibition on fibroblasts (≥99%). While gO GT replacement did not influence sNRP2-Fc inhibition at 1.25 μg/ml on epithelial cells (97% to 99%), it rendered recombinant mutant GT1c/3 moderately accessible to fibroblast inhibition (40%). In contrast to the steep sPDGFRα-Fc inhibition curves (slope of >1.0), sNRP2-Fc dose-response curves on epithelial cells displayed slopes of ∼1.0, suggesting functional differences between these entry inhibitors. Our findings demonstrate that artificially generated gO recombinants rather than the major gO genotypic forms may affect the inhibitory capacities of sPDGFRα and sNRP2 in a cell type-dependent manner.IMPORTANCE Human cytomegalovirus (HCMV) is known for its broad cell tropism, as reflected by the different organs and tissues affected by HCMV infection. Hence, inhibition of HCMV entry into distinct cell types could be considered a promising therapeutic option to limit cell-free HCMV infection. Soluble forms of cellular entry receptor PDGFRα rather than those of entry receptor neuropilin-2 inhibit infection of multiple cell types. sPDGFRα specifically interacts with gO of the trimeric gH/gL/gO envelope glycoprotein complex. HCMV strains may differ with respect to the amounts of trimer in virions and the highly polymorphic gO sequence. In this study, we show that the major gO genotypes of HCMV that are also found in vivo are similarly well inhibited by sPDGFRα. Novel gO genotypic forms potentially emerging through recombination, however, may evade sPDGFRα inhibition on epithelial cells. These findings provide useful additional information for the future development of anti-HCMV therapeutic compounds based on sPDGFRα.
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Affiliation(s)
- Nadja Brait
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Tanja Stögerer
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Julia Kalser
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Barbara Adler
- Max von Pettenkofer Institute for Virology, Ludwig Maximilians University Munich, Munich, Germany
| | - Ines Kunz
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Max Benesch
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Barbara Kropff
- Virologisches Institut, Klinische und Molekulare Virologie, Friedrich Alexander Universität Erlangen Nürnberg, Erlangen, Germany
| | - Michael Mach
- Virologisches Institut, Klinische und Molekulare Virologie, Friedrich Alexander Universität Erlangen Nürnberg, Erlangen, Germany
| | | | - Irene Görzer
- Center for Virology, Medical University of Vienna, Vienna, Austria
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Park J, Gill KS, Aghajani AA, Heredia JD, Choi H, Oberstein A, Procko E. Engineered receptors for human cytomegalovirus that are orthogonal to normal human biology. PLoS Pathog 2020; 16:e1008647. [PMID: 32559251 PMCID: PMC7329128 DOI: 10.1371/journal.ppat.1008647] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 07/01/2020] [Accepted: 05/20/2020] [Indexed: 12/12/2022] Open
Abstract
A trimeric glycoprotein complex on the surface of human cytomegalovirus (HCMV) binds to platelet-derived growth factor (PDGF) receptor α (PDGFRα) to mediate host cell recognition and fusion of the viral and cellular membranes. Soluble PDGFRα potently neutralizes HCMV in tissue culture, and its potential use as an antiviral therapeutic has the benefit that any escape mutants will likely be attenuated. However, PDGFRα binds multiple PDGF ligands in the human body as part of developmental programs in embryogenesis and continuing through adulthood. Any therapies with soluble receptor therefore come with serious efficacy and safety concerns, especially for the treatment of congenital HCMV. Soluble virus receptors that are orthogonal to human biology might resolve these concerns. This engineering problem is solved by deep mutational scanning on the D2-D3 domains of PDGFRα to identify variants that maintain interactions with the HCMV glycoprotein trimer in the presence of competing PDGF ligands. Competition by PDGFs is conformation-dependent, whereas HCMV trimer binding is independent of proper D2-D3 conformation, and many mutations at the receptor-PDGF interface are suitable for functionally separating trimer from PDGF interactions. Purified soluble PDGFRα carrying a targeted mutation succeeded in displaying wild type affinity for HCMV trimer with a simultaneous loss of PDGF binding, and neutralizes trimer-only and trimer/pentamer-expressing HCMV strains infecting fibroblasts or epithelial cells. Overall, this work makes important progress in the realization of soluble HCMV receptors for clinical application. Human cytomegalovirus (HCMV) causes severe disease in transplant recipients and immunocompromised patients, and infections in a fetus or neonate are responsible for life-long neurological defects. Cell entry is in part mediated by a trimeric glycoprotein complex on the viral surface, which binds tightly to the host receptor PDGFRα. The soluble extracellular region of PDGFRα can be used as an antiviral agent to potently neutralize the virus in vitro. However, PDGFRα ordinarily binds growth factors in the human body to regulate developmental programs, which will limit the in vivo efficacy and safety of soluble PDGFRα. Using saturation mutagenesis and selections in human cell culture, mutations in PDGFRα are identified that eliminate off-target growth factor interactions while preserving HCMV binding and neutralization.
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Affiliation(s)
- Jihye Park
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Kevin Sean Gill
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Ali Asghar Aghajani
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Jeremiah Dallas Heredia
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Hannah Choi
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Adam Oberstein
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
- Cancer Center at Illinois (CCIL), University of Illinois, Urbana, Illinois, United States of America
- * E-mail:
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39
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Specialization for Cell-Free or Cell-to-Cell Spread of BAC-Cloned Human Cytomegalovirus Strains Is Determined by Factors beyond the UL128-131 and RL13 Loci. J Virol 2020; 94:JVI.00034-20. [PMID: 32321807 DOI: 10.1128/jvi.00034-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/13/2020] [Indexed: 12/17/2022] Open
Abstract
It is widely held that clinical isolates of human cytomegalovirus (HCMV) are highly cell associated, and mutations affecting the UL128-131 and RL13 loci that arise in culture lead to the appearance of a cell-free spread phenotype. The bacterial artificial chromosome (BAC) clone Merlin (ME) expresses abundant UL128-131, is RL13 impaired, and produces low infectivity virions in fibroblasts, whereas TB40/e (TB) and TR are low in UL128-131, are RL13 intact, and produce virions of much higher infectivity. Despite these differences, quantification of spread by flow cytometry revealed remarkably similar spread efficiencies in fibroblasts. In epithelial cells, ME spread more efficiently, consistent with robust UL128-131 expression. Strikingly, ME spread far better than did TB or TR in the presence of neutralizing antibodies on both cell types, indicating that ME is not simply deficient at cell-free spread but is particularly efficient at cell-to-cell spread, whereas TB and TR cell-to-cell spread is poor. Sonically disrupted ME-infected cells contained scant infectivity, suggesting that the efficient cell-to-cell spread mechanism of ME depends on features of the intact cells such as junctions or intracellular trafficking processes. Even when UL128-131 was transcriptionally repressed, cell-to-cell spread of ME was still more efficient than that of TB or TR. Moreover, RL13 expression comparably reduced both cell-free and cell-to-cell spread of all three strains, suggesting that it acts at a stage of assembly and/or egress common to both routes of spread. Thus, HCMV strains can be highly specialized for either for cell-free or cell-to-cell spread, and these phenotypes are determined by factors beyond the UL128-131 or RL13 loci.IMPORTANCE Both cell-free and cell-to-cell spread are likely important for the natural biology of HCMV. In culture, strains clearly differ in their capacity for cell-free spread as a result of differences in the quantity and infectivity of extracellular released progeny. However, it has been unclear whether "cell-associated" phenotypes are simply the result of poor cell-free spread or are indicative of particularly efficient cell-to-cell spread mechanisms. By measuring the kinetics of spread at early time points, we were able to show that HCMV strains can be highly specialized to either cell-free or cell-to-cell mechanisms, and this was not strictly linked the efficiency of cell-free spread. Our results provide a conceptual approach to evaluating intervention strategies for their ability to limit cell-free or cell-to-cell spread as independent processes.
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Guinea pig cytomegalovirus trimer complex gH/gL/gO uses PDGFRA as universal receptor for cell fusion and entry. Virology 2020; 548:236-249. [PMID: 32791352 DOI: 10.1016/j.virol.2020.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/14/2022]
Abstract
Species-specific guinea pig cytomegalovirus (GPCMV) causes congenital CMV and the virus encodes homolog glycoprotein complexes to human CMV, including gH-based trimer (gH/gL/gO) and pentamer-complex (PC). Platelet-derived growth factor receptor alpha (gpPDGFRA), only present on fibroblast cells, was identified via CRISPR as the putative receptor for PC-independent GPCMV infection. Immunoprecipitation assays demonstrated direct interaction of gH/gL/gO with gpPDGFRA but not in absence of gO. Expression of viral gB also resulted in precipitation of gB/gH/gL/gO/gpPDGFRA complex. Cell-cell fusion assays determined that expression of gpPDGFRA and gH/gL/gO in adjacent cells enabled cell fusion, which was not enhanced by gB. N-linked gpPDGFRA glycosylation inhibition had limited effect and blocking tyrosine kinase (TK) transduction had no impact on infection. Ectopically expressed gpPDGFRA or TK-domain mutant in trophoblast or epithelial cells previously non-susceptible to GPCMV(PC-) enabled viral infection. In contrast, transient human PDGFRA expression did not complement GPCMV(PC-) infection, a potential basis for viral species specificity.
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Sandonís V, García-Ríos E, McConnell MJ, Pérez-Romero P. Role of Neutralizing Antibodies in CMV Infection: Implications for New Therapeutic Approaches. Trends Microbiol 2020; 28:900-912. [PMID: 32448762 DOI: 10.1016/j.tim.2020.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 02/06/2023]
Abstract
Cytomegalovirus (CMV) infection elicits a potent immune response that includes the stimulation of antibodies with neutralizing activity. Recent studies have focused on elucidating the role of neutralizing antibodies in protecting against CMV infection and disease and characterizing viral antigens against which neutralizing antibodies are directed. Here, we provide a synthesis of recent data regarding the role of neutralizing antibodies in protection against CMV infection/disease. We consider the role of humoral immunity in the context of the global CMV-specific immune response, and the implications that recent findings have for vaccine and antibody-based therapy design.
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Affiliation(s)
- Virginia Sandonís
- Unit of Infectious Diseases, Hospital Universitario '12 de Octubre', Instituto de Investigación Hospital '12 de Octubre' (i+12), Madrid, Spain
| | - Estéfani García-Ríos
- National Center for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Michael J McConnell
- National Center for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Pilar Pérez-Romero
- National Center for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
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Cui X, Cao Z, Wang S, Adler SP, McVoy MA, Snapper CM. Immunization with Human Cytomegalovirus Core Fusion Machinery and Accessory Envelope Proteins Elicit Strong Synergistic Neutralizing Activities. Vaccines (Basel) 2020; 8:vaccines8020179. [PMID: 32294946 PMCID: PMC7348949 DOI: 10.3390/vaccines8020179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/04/2020] [Accepted: 04/10/2020] [Indexed: 12/15/2022] Open
Abstract
Human cytomegalovirus (HCMV) core fusion machinery proteins gB and gH/gL, and accessory proteins UL128/UL130/UL131A, are the key envelope proteins that mediate HCMV entry into and infection of host cells. To determine whether these HCMV envelope proteins could elicit neutralizing activities synergistically, we immunized rabbits with individual or various combinations of these proteins adsorbed to aluminum hydroxide mixed with CpG-ODN. We then analyzed serum neutralizing activities with multiple HCMV laboratory strains and clinical isolates. HCMV trimeric gB and gH/gL elicited high and moderate titers of HCMV neutralizing activity, respectively. HCMV gB in combination with gH/gL elicited up to 17-fold higher HCMV neutralizing activities compared to the sum of neutralizing activity elicited by the individual proteins analyzed with both fibroblasts and epithelial cells. HCMV gB+gH/gL+UL128/UL130/UL131A in combination increased the neutralizing activity up to 32-fold compared to the sum of neutralizing activities elicited by the individual proteins analyzed with epithelial cells. Adding UL128/UL130/UL131A to gB and gH/gL combination did not increase further the HCMV neutralizing activity analyzed with fibroblasts. These data suggest that the combination of HCMV core fusion machinery envelope proteins gB+gH/gL or the combination of gB and pentameric complex could be ideal vaccine candidates that would induce optimal immune responses against HCMV infection.
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Affiliation(s)
- Xinle Cui
- The Institute for Vaccine Research and Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Correspondence: ; Tel.: +1-301-295-3498
| | - Zhouhong Cao
- The Institute for Vaccine Research and Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Shuishu Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Michael A. McVoy
- Department of Pediatrics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Clifford M. Snapper
- The Institute for Vaccine Research and Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Polymorphisms in Human Cytomegalovirus Glycoprotein O (gO) Exert Epistatic Influences on Cell-Free and Cell-to-Cell Spread and Antibody Neutralization on gH Epitopes. J Virol 2020; 94:JVI.02051-19. [PMID: 31996433 DOI: 10.1128/jvi.02051-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 01/24/2020] [Indexed: 02/06/2023] Open
Abstract
Human cytomegalovirus (HCMV) glycoproteins H and L (gH/gL) can be bound by either gO or the UL128 to UL131 proteins (referred to here as UL128-131) to form complexes that facilitate entry and spread, and the complexes formed are important targets of neutralizing antibodies. Strains of HCMV vary considerably in the levels of gH/gL/gO and gH/gL/UL128-131, and this can impact infectivity and cell tropism. In this study, we investigated how natural interstrain variation in the amino acid sequence of gO influences the biology of HCMV. Heterologous gO recombinants were constructed in which 6 of the 8 alleles or genotypes (GT) of gO were analyzed in the backgrounds of strains TR and Merlin (ME). The levels of gH/gL complexes were not affected, but there were impacts on entry, spread, and neutralization by anti-gH antibodies. AD169 (AD) gO (GT1a) [referred to here as ADgO(GT1a)] drastically reduced cell-free infectivity of both strains on fibroblasts and epithelial cells. PHgO(GT2a) increased cell-free infectivity of TR in both cell types, but spread in fibroblasts was impaired. In contrast, spread of ME in both cell types was enhanced by Towne (TN) gO (GT4), despite similar cell-free infectivity. TR expressing TNgO(GT4) was resistant to neutralization by anti-gH antibodies AP86 and 14-4b, whereas ADgO(GT1a) conferred resistance to 14-4b but enhanced neutralization by AP86. Conversely, ME expressing ADgO(GT1a) was more resistant to 14-4b. These results suggest that (i) there are mechanistically distinct roles for gH/gL/gO in cell-free and cell-to-cell spread, (ii) gO isoforms can differentially shield the virus from neutralizing antibodies, and (iii) effects of gO polymorphisms are epistatically dependent on other variable loci.IMPORTANCE Advances in HCMV population genetics have greatly outpaced understanding of the links between genetic diversity and phenotypic variation. Moreover, recombination between genotypes may shuffle variable loci into various combinations with unknown outcomes. UL74(gO) is an important determinant of HCMV infectivity and one of the most diverse loci in the viral genome. By analyzing interstrain heterologous UL74(gO) recombinants, we showed that gO diversity can have dramatic impacts on cell-free and cell-to-cell spread as well as on antibody neutralization and that the manifestation of these impacts can be subject to epistatic influences of the global genetic background. These results highlight the potential limitations of laboratory studies of HCMV biology that use single, isolated genotypes or strains.
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Böffert R, Businger R, Preiß H, Ehmann D, Truffault V, Simon C, Ruetalo N, Hamprecht K, Müller P, Wehkamp J, Schindler M. The human α-defensin-derived peptide HD5(1-9) inhibits cellular attachment and entry of human cytomegalovirus. Antiviral Res 2020; 177:104779. [PMID: 32209394 DOI: 10.1016/j.antiviral.2020.104779] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 10/24/2022]
Abstract
Human cytomegalovirus (HCMV) infection causes severe illness in newborns and immunocompromised patients. Since treatment options are limited there is an unmet need for new therapeutic approaches. Defensins are cationic peptides, produced by various human tissues, which serve as antimicrobial effectors of the immune system. Furthermore, some defensins are proteolytically cleaved, resulting in the generation of smaller fragments with increased activity. Together, this led us to hypothesize that defensin-derived peptides are natural human inhibitors of virus infection with low toxicity. We screened several human defensin HNP4- and HD5-derived peptides and found HD5(1-9) to be antiviral without toxicity at high concentrations. HD5(1-9) inhibited HCMV cellular attachment and thereby entry and was active against primary as well as a multiresistant HCMV isolate. Moreover, cysteine and arginine residues were identified to mediate the antiviral activity of HD5(1-9). Altogether, defensin-derived peptides, in particular HD5(1-9), qualify as promising candidates for further development as a novel class of HCMV entry inhibitors.
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Affiliation(s)
- Rebecca Böffert
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Ramona Businger
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Hannes Preiß
- Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany
| | - Dirk Ehmann
- Department for Internal Medicine I, University Hospital Tübingen, Tübingen, Germany
| | | | - Claudia Simon
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Natalia Ruetalo
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Klaus Hamprecht
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Patrick Müller
- Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany; Translational Oncology Division, University Hospital Tübingen, Tübingen, Germany
| | - Jan Wehkamp
- Department for Internal Medicine I, University Hospital Tübingen, Tübingen, Germany
| | - Michael Schindler
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany.
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Rahbar A, AlKharusi A, Costa H, Pantalone MR, Kostopoulou ON, Cui HL, Carlsson J, Rådestad AF, Söderberg-Naucler C, Norstedt G. Human Cytomegalovirus Infection Induces High Expression of Prolactin and Prolactin Receptors in Ovarian Cancer. BIOLOGY 2020; 9:biology9030044. [PMID: 32121009 PMCID: PMC7150842 DOI: 10.3390/biology9030044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/07/2020] [Accepted: 02/09/2020] [Indexed: 11/30/2022]
Abstract
One of the potential biomarkers for ovarian cancer patients is high serum level of prolactin (PRL), which is a growth factor that may promote tumor cell growth. The prolactin receptor (PRLR) and human cytomegalovirus (HCMV) proteins are frequently detected in ovarian tumor tissue specimens, but the potential impact of HCMV infection on the PRL system have so far not been investigated. In this study, HCMV’s effects on PRL and PRLR expression were assessed in infected ovarian cancer cells (SKOV3) by PCR and Western blot techniques. The levels of both PRL and PRLR transcripts as well as the corresponding proteins were highly increased in HCMV-infected SKOV3 cells. Tissue specimens obtained from 10 patients with ovarian cancer demonstrated high expression of PRLR, HCMV-IE, and pp65 proteins. Extensive expression of PRLR was detected in all examined ovarian tumor tissue specimens except for one from a patient who had focal expression of PRLR and this patient was HCMV-negative in her tumor. In conclusion, PRL and PRLR were induced to high levels in HCMV-infected ovarian cancer cells and PRLR expression was extensively detected in HCMV-infected ovarian tissue specimens. Highly induced PRL and PRLR by HCMV infection may be of relevance for the oncomodulatory role of this virus in ovarian cancer.
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Affiliation(s)
- Afsar Rahbar
- Department of Medicine, Solna, Division of Microbial Pathogenesis, BioClinicum, Karolinska Institutet, 171 64 Solna, Sweden; (H.C.); (M.R.P.); (O.N.K.); (H.L.C.); (C.S.-N.)
- Division of Neurosurgery, Karolinska University Hospital, 171 64 Stockholm, Sweden
- Correspondence: (A.R.); (A.K.)
| | - Amira AlKharusi
- Department of Physiology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 135, Oman
- Correspondence: (A.R.); (A.K.)
| | - Helena Costa
- Department of Medicine, Solna, Division of Microbial Pathogenesis, BioClinicum, Karolinska Institutet, 171 64 Solna, Sweden; (H.C.); (M.R.P.); (O.N.K.); (H.L.C.); (C.S.-N.)
- Division of Neurosurgery, Karolinska University Hospital, 171 64 Stockholm, Sweden
| | - Mattia Russel Pantalone
- Department of Medicine, Solna, Division of Microbial Pathogenesis, BioClinicum, Karolinska Institutet, 171 64 Solna, Sweden; (H.C.); (M.R.P.); (O.N.K.); (H.L.C.); (C.S.-N.)
- Division of Neurosurgery, Karolinska University Hospital, 171 64 Stockholm, Sweden
| | - Ourania N. Kostopoulou
- Department of Medicine, Solna, Division of Microbial Pathogenesis, BioClinicum, Karolinska Institutet, 171 64 Solna, Sweden; (H.C.); (M.R.P.); (O.N.K.); (H.L.C.); (C.S.-N.)
- Division of Neurosurgery, Karolinska University Hospital, 171 64 Stockholm, Sweden
| | - Huanhuan L. Cui
- Department of Medicine, Solna, Division of Microbial Pathogenesis, BioClinicum, Karolinska Institutet, 171 64 Solna, Sweden; (H.C.); (M.R.P.); (O.N.K.); (H.L.C.); (C.S.-N.)
- Division of Neurosurgery, Karolinska University Hospital, 171 64 Stockholm, Sweden
| | - Joseph Carlsson
- Division of Pathology and Cytology, Karolinska University Hospital, 171 77 Stockholm, Sweden;
- Department of Oncology and Pathology, BioClinicum, Karolinska Institutet, 171 64 Solna, Sweden
| | - Angelique Flöter Rådestad
- Department of Women’s and Children’s Health, Karolinska Institutet, 171 77 Stockholm, Sweden;
- Division of Obstetrics and Gynecology, Karolinska University Hospital, 171 77 Stockholm, Sweden
| | - Cecilia Söderberg-Naucler
- Department of Medicine, Solna, Division of Microbial Pathogenesis, BioClinicum, Karolinska Institutet, 171 64 Solna, Sweden; (H.C.); (M.R.P.); (O.N.K.); (H.L.C.); (C.S.-N.)
- Division of Neurosurgery, Karolinska University Hospital, 171 64 Stockholm, Sweden
| | - Gunnar Norstedt
- Department of Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 135, Oman;
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Endoplasmic Reticulum (ER) Reorganization and Intracellular Retention of CD58 Are Functionally Independent Properties of the Human Cytomegalovirus ER-Resident Glycoprotein UL148. J Virol 2020; 94:JVI.01435-19. [PMID: 31801856 DOI: 10.1128/jvi.01435-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 11/26/2019] [Indexed: 12/27/2022] Open
Abstract
The human cytomegalovirus (HCMV) endoplasmic reticulum (ER)-resident glycoprotein UL148 is posited to play roles in immune evasion and regulation of viral cell tropism. UL148 prevents cell surface presentation of the immune cell costimulatory ligand CD58 while promoting maturation and virion incorporation of glycoprotein O, a receptor binding subunit for an envelope glycoprotein complex involved in entry. Meanwhile, UL148 activates the unfolded protein response (UPR) and causes large-scale reorganization of the ER. In order to determine whether the seemingly disparate effects of UL148 are related or discrete, we generated six charged cluster-to-alanine (CCTA) mutants within the UL148 ectodomain and compared them to wild-type UL148, both in the context of infection studies using recombinant viruses and in ectopic expression experiments, assaying for effects on ER remodeling and CD58 surface presentation. Two mutants, targeting charged clusters spanning residues 79 to 83 (CC3) and 133 to 136 (CC4), retained the potential to impede CD58 surface presentation. Of the six mutants, only CC3 retained the capacity to reorganize the ER, but it showed a partial phenotype. Wild-type UL148 accumulates in a detergent-insoluble form during infection. However, all six CCTA mutants were fully soluble, which implies a relationship between insolubility and organelle remodeling. Additionally, we found that the chimpanzee cytomegalovirus UL148 homolog suppresses surface presentation of CD58 but fails to reorganize the ER, while the homolog from rhesus cytomegalovirus shows neither activity. Collectively, our findings illustrate various degrees of functional divergence between homologous primate cytomegalovirus immunevasins and suggest that the capacity to cause ER reorganization is unique to HCMV UL148.IMPORTANCE In myriad examples, viral gene products cause striking effects on cells, such as activation of stress responses. It can be challenging to decipher how such effects contribute to the biological roles of the proteins. The HCMV glycoprotein UL148 retains CD58 within the ER, thereby preventing it from reaching the cell surface, where it functions to stimulate cell-mediated antiviral responses. Intriguingly, UL148 also triggers the formation of large, ER-derived membranous structures and activates the UPR, a set of signaling pathways involved in adaptation to ER stress. We demonstrate that the potential of UL148 to reorganize the ER and to retain CD58 are separable by mutagenesis and, possibly, by evolution, since chimpanzee cytomegalovirus UL148 retains CD58 but does not remodel the ER. Our findings imply that ER reorganization contributes to other roles of UL148, such as modulation of alternative viral glycoprotein complexes that govern the virus' ability to infect different cell types.
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Paradowska E, Jabłońska A, Studzińska M, Kasztelewicz B, Wiśniewska-Ligier M, Dzierżanowska-Fangrat K, Woźniakowska-Gęsicka T, Czech-Kowalska J. Distribution of the CMV glycoprotein gH/gL/gO and gH/gL/pUL128/pUL130/pUL131A complex variants and associated clinical manifestations in infants infected congenitally or postnatally. Sci Rep 2019; 9:16352. [PMID: 31705022 PMCID: PMC6841705 DOI: 10.1038/s41598-019-52906-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 10/22/2019] [Indexed: 11/09/2022] Open
Abstract
Human cytomegalovirus (CMV) is a major cause of morbidity in fetuses following intrauterine infection. The glycoprotein (g) envelope trimeric gH/gL/gO and pentameric gH/gL/pUL128/pUL130/pUL131A complexes are required for CMV entry into fibroblasts and endothelial/epithelial cells, respectively, and both are targets for neutralizing antibodies. The role of sequence variability among viral strains in the outcome of congenital CMV infection is controversial. Variation in the CMV UL75 gene encoding glycoprotein H (gH), the UL115 (gL), the UL74 (gO), and the UL128 locus (UL128L) encoding three structural proteins (pUL128, pUL130, and pUL131A) was determined in 82 newborns with congenital CMV infection and 113 infants with postnatal or unproven congenital CMV infection. Genotyping was performed by sequencing analysis of PCR-amplified fragments and the PCR-restriction fragment length polymorphism (RFLP) method, and the viral load was measured by quantitative real-time PCR. The obtained results demonstrated that (1) different CMV variants and mixed CMV infections can be detected in newborns infected congenitally; (2) the gH1 genotype, UL130 variant 6, and UL131A variant 1 were associated with some signs/symptoms within cohort of pediatric patients, mainly consisting of infants with symptomatic CMV infection. The results revealed that pUL130, pUL131A, and gH polymorphisms seemed to be associated with the outcome of CMV infection in infants.
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Affiliation(s)
- Edyta Paradowska
- Laboratory of Virology, Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland.
| | - Agnieszka Jabłońska
- Laboratory of Virology, Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Mirosława Studzińska
- Laboratory of Virology, Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Beata Kasztelewicz
- Department of Clinical Microbiology and Immunology, The Children's Memorial Health Institute, Warsaw, Poland
| | - Małgorzata Wiśniewska-Ligier
- Department of Pediatrics, Immunology, and Nephrology, Polish Mother's Memorial Hospital Research Institute, Lodz, Poland
- 3rd Department of Pediatrics, Polish Mother's Memorial Hospital Research Institute, Lodz, Poland
| | | | | | - Justyna Czech-Kowalska
- Department of Neonatology and Neonatal Intensive Care, The Children's Memorial Health Institute, Warsaw, Poland
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Ye X, Gui X, Freed DC, Ku Z, Li L, Chen Y, Xiong W, Fan X, Su H, He X, Rustandi RR, Loughney JW, Ma N, Espeseth AS, Liu J, Zhu H, Wang D, Zhang N, Fu TM, An Z. Identification of adipocyte plasma membrane-associated protein as a novel modulator of human cytomegalovirus infection. PLoS Pathog 2019; 15:e1007914. [PMID: 31356650 PMCID: PMC6687193 DOI: 10.1371/journal.ppat.1007914] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 08/08/2019] [Accepted: 06/13/2019] [Indexed: 12/17/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous pathogen that can cause disability in newborns and serious clinical diseases in immunocompromised patients. HCMV has a large genome with enormous coding potential; its viral particles are equipped with complicated glycoprotein complexes and can infect a wide range of human cells. Although multiple host cellular receptors interacting with viral glycoproteins have been reported, the mechanism of HCMV infection remains a mystery. Here we report identification of adipocyte plasma membrane-associated protein (APMAP) as a novel modulator active in the early stage of HCMV infection. APMAP is necessary for HCMV infection in both epithelial cells and fibroblasts; knockdown of APMAP expression significantly reduced HCMV infection of these cells. Interestingly, ectopic expression of human APMAP in cells refractory to HCMV infection, such as canine MDCK and murine NIH/3T3 cells, promoted HCMV infection. Furthermore, reduction in viral immediate early (IE) gene transcription at 6 h post infection and delayed nucleus translocation of tegument delivered pp65 at 4 h post infection were detected in APMAP-deficient cells but not in the wildtype cells. These results suggest that APMAP plays a role in the early stage of HCMV infection. Results from biochemical studies of APMAP and HCMV proteins suggest that APMAP could participate in HCMV infection through interaction with gH/gL containing glycoprotein complexes at low pH and mediate nucleus translocation of tegument pp65. Taken together, our results suggest that APMAP functions as a modulator promoting HCMV infection in multiple cell types and is an important player in the complex HCMV infection mechanism.
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Affiliation(s)
- Xiaohua Ye
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
| | - Xun Gui
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
| | - Daniel C. Freed
- MRL, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Zhiqiang Ku
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
| | - Leike Li
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
| | - Yuanzhi Chen
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
| | - Wei Xiong
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
| | - Xuejun Fan
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
| | - Hang Su
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, China
| | - Xi He
- MRL, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | | | - John W. Loughney
- MRL, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Ningning Ma
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, China
| | - Amy S. Espeseth
- MRL, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Jian Liu
- Rutgers Medical School of New Jersey, Newark, NJ, United States of America
| | - Hua Zhu
- Rutgers Medical School of New Jersey, Newark, NJ, United States of America
| | - Dai Wang
- MRL, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Ningyan Zhang
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
- * E-mail: (NZ); (TMF); (ZN)
| | - Tong-Ming Fu
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
- MRL, Merck & Co., Inc., Kenilworth, NJ, United States of America
- * E-mail: (NZ); (TMF); (ZN)
| | - Zhiqiang An
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Texas, United States of America
- * E-mail: (NZ); (TMF); (ZN)
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Cui X, Cao Z, Wang S, Flora M, Adler SP, McVoy MA, Snapper CM. Immunization of Rabbits with Recombinant Human Cytomegalovirus Trimeric versus Monomeric gH/gL Protein Elicits Markedly Higher Titers of Antibody and Neutralization Activity. Int J Mol Sci 2019; 20:ijms20133158. [PMID: 31261659 PMCID: PMC6651862 DOI: 10.3390/ijms20133158] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 06/21/2019] [Accepted: 06/24/2019] [Indexed: 11/30/2022] Open
Abstract
Congenital human cytomegalovirus (HCMV) infection and HCMV infection of immunosuppressed patients cause significant morbidity and mortality, and vaccine development against HCMV is a major public health priority. HCMV envelope glycoproteins gB, gH, and gL, which constitute the core fusion machinery, play critical roles in HCMV fusion and entry into host cells. HCMV gB and gH/gL have been reported to elicit potent neutralizing antibodies. Recently, the gB/gH/gL complex was identified in the envelope of HCMV virions, and 16–50% of the total gH/gL bound to gB, forming the gB/gH/gL complex. These findings make the gB/gH/gL a unique HCMV vaccine candidate. We previously reported the production of HCMV trimeric gB and gH/gL heterodimers, and immunization with a combination of trimeric gB and gH/gL heterodimers elicited strong synergistic HCMV-neutralizing activity. To further improve the immunogenicity of gH/gL, we produced trimeric gH/gL. Rabbits immunized with HCMV trimeric gH/gL induced up to 38-fold higher serum titers of gH/gL-specific IgG relative to HCMV monomeric gH/gL, and elicited ~10-fold higher titers of complement-dependent and complement-independent HCMV-neutralizing activity for both epithelial cells and fibroblasts. HCMV trimeric gH/gL in combination with HCMV trimeric gB would be a novel promising HCMV vaccine candidate that could induce highly potent neutralizing activities.
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Affiliation(s)
- Xinle Cui
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
| | - Zhouhong Cao
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Shuishu Wang
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Michael Flora
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | | | - Michael A McVoy
- Department of Pediatrics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Clifford M Snapper
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Abstract
In this chapter, we present an overview on betaherpesvirus entry, with a focus on human cytomegalovirus, human herpesvirus 6A and human herpesvirus 6B. Human cytomegalovirus (HCMV) is a complex human pathogen with a genome of 235kb encoding more than 200 genes. It infects a broad range of cell types by switching its viral ligand on the virion, using the trimer gH/gL/gO for infection of fibroblasts and the pentamer gH/gL/UL128/UL130/UL131 for infection of other cells such as epithelial and endothelial cells, leading to membrane fusion mediated by the fusion protein gB. Adding to this scenario, however, accumulating data reveal the actual complexity in the viral entry process of HCMV with an intricate interplay among viral and host factors. Key novel findings include the identification of entry receptors platelet-derived growth factor-α receptor (PDGFRα) and Netropilin-2 (Nrp2) for trimer and pentamer, respectively, the determination of atomic structures of the fusion protein gB and the pentamer, and the in situ visualization of the state and arrangement of functional glycoproteins on virion. This is covered in the first part of this review. The second part focusses on HHV-6 which is a T lymphotropic virus categorized as two distinct virus species, HHV-6A and HHV-6B based on differences in epidemiological, biological, and immunological aspects, although homology of their entire genome sequences is nearly 90%. HHV-6B is a causative agent of exanthema subitum (ES), but the role of HHV-6A is unknown. HHV-6B reactivation occasionally causes encephalitis in patients with hematopoietic stem cell transplant. The HHV-6 specific envelope glycoprotein complex, gH/gL/gQ1/gQ2 is a viral ligand for the entry receptor. Recently, each virus has been found to recognize a different cellular receptor, CD46 for HHV 6A amd CD134 for HHV 6B. These findings show that distinct receptor recognition differing between both viruses could explain their different pathogenesis.
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Affiliation(s)
- Mitsuhiro Nishimura
- Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yasuko Mori
- Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan.
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