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Ma J, Bruce K, Stevenson PG, Farrell HE. Mouse cytomegalovirus lacking sgg1 shows reduced import into the salivary glands. J Gen Virol 2024; 105:002013. [PMID: 39093048 PMCID: PMC11296724 DOI: 10.1099/jgv.0.002013] [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: 05/16/2024] [Accepted: 07/22/2024] [Indexed: 08/04/2024] Open
Abstract
Cytomegaloviruses (CMVs) transmit via chronic shedding from the salivary glands. How this relates to the broad cell tropism they exhibit in vitro is unclear. Human CMV (HCMV) infection presents only after salivary gland infection is established. Murine CMV (MCMV) is therefore useful to analyse early infection events. It reaches the salivary glands via infected myeloid cells. Three adjacent spliced genes designated as m131/129 (MCK-2), sgg1 and sgg1.1, positional homologues of the HCMV UL128/130/131 tropism determinants, are implicated. We show that a sgg1 null mutant is defective in infected myeloid cell entry into the salivary glands, a phenotype distinct from MCMV lacking MCK-2. These data point to a complex, multi-step process of salivary gland colonization.
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Affiliation(s)
- Jiawei Ma
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
| | - Kimberley Bruce
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
| | - Philip G. Stevenson
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
| | - Helen E. Farrell
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
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2
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Xie W, Bruce K, Stevenson PG, Farrell HE. Indirect CD4 + T cell protection against persistent MCMV infection by NK cells requires IFNγ. J Gen Virol 2024; 105. [PMID: 38271001 DOI: 10.1099/jgv.0.001956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024] Open
Abstract
Host control of mouse cytomegalovirus (MCMV) infection of MHCII- salivary gland acinar cells is mediated by CD4+ T cells, but how they protect is unclear. Here, we show CD4+ T cells control MCMV indirectly in the salivary gland, via IFNγ engagement with uninfected, but antigen+ MHCII+ APC and recruitment of NK cells to infected cell foci. This immune mechanism renders direct contact of CD4+ T cells with infected cells unnecessary and may represent a host strategy to overcome viral immune evasion.
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Affiliation(s)
- Wanxiaojie Xie
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
| | - Kimberley Bruce
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
| | - Philip G Stevenson
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
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Eletreby M, Thiessen L, Prager A, Brizic I, Materljan J, Kubic L, Jäger K, Jurinović K, Jerak J, Krey K, Adler B. Dissecting the cytomegalovirus CC chemokine: Chemokine activity and gHgLchemokine-dependent cell tropism are independent players in CMV infection. PLoS Pathog 2023; 19:e1011793. [PMID: 38064525 PMCID: PMC10732436 DOI: 10.1371/journal.ppat.1011793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/20/2023] [Accepted: 11/01/2023] [Indexed: 12/21/2023] Open
Abstract
Like all herpesviruses, cytomegaloviruses (CMVs) code for many immunomodulatory proteins including chemokines. The human cytomegalovirus (HCMV) CC chemokine pUL128 has a dual role in the infection cycle. On one hand, it forms the pentameric receptor-binding complex gHgLpUL(128,130,131A), which is crucial for the broad cell tropism of HCMV. On the other hand, it is an active chemokine that attracts leukocytes and shapes their activation. All animal CMVs studied so far have functionally homologous CC chemokines. In murine cytomegalovirus (MCMV), the CC chemokine is encoded by the m131/m129 reading frames. The MCMV CC chemokine is called MCK2 and forms a trimeric gHgLMCK2 entry complex. Here, we have generated MCK2 mutant viruses either unable to form gHgLMCK2 complexes, lacking the chemokine function or lacking both functions. By using these viruses, we could demonstrate that gHgLMCK2-dependent entry and MCK2 chemokine activity are independent functions of MCK2 in vitro and in vivo. The gHgLMCK2 complex promotes the tropism for leukocytes like macrophages and dendritic cells and secures high titers in salivary glands in MCMV-infected mice independent of the chemokine activity of MCK2. In contrast, reduced early antiviral T cell responses in MCMV-infected mice are dependent on MCK2 being an active chemokine and do not require the formation of gHgLMCK2 complexes. High levels of CCL2 and IFN-γ in spleens of infected mice and MCMV virulence depend on both, the formation of gHgLMCK2 complexes and the MCK2 chemokine activity. Thus, independent and concerted functions of MCK2 serving as chemokine and part of a gHgL entry complex shape antiviral immunity and virus dissemination.
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Affiliation(s)
- Marwa Eletreby
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
| | - Lena Thiessen
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
| | - Adrian Prager
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
| | - Ilija Brizic
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jelena Materljan
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Lucie Kubic
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
| | - Katharina Jäger
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
| | - Križan Jurinović
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
| | - Josipa Jerak
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
| | - Karsten Krey
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
| | - Barbara Adler
- Max von Pettenkofer Institute & Gene Center, Virology, Faculty of Medicine, Ludwig- Maximilians-University Munich, Munich, Germany
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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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Bošnjak B, Lueder Y, Messerle M, Förster R. Imaging cytomegalovirus infection and ensuing immune responses. Curr Opin Immunol 2023; 82:102307. [PMID: 36996701 DOI: 10.1016/j.coi.2023.102307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/30/2023]
Abstract
Cytomegaloviruses (CMVs) possess exquisite mechanisms enabling colonization, replication, and release allowing spread to new hosts. Moreover, they developed ways to escape the control of the host immune responses and hide latently within the host cells. Here, we outline studies that visualized individual CMV-infected cells using reporter viruses. These investigations provided crucial insights into all steps of CMV infection and mechanisms the host's immune response struggles to control it. Uncovering complex viral and cellular interactions and underlying molecular as well as immunological mechanisms are a prerequisite for the development of novel therapeutic interventions for successful treatment of CMV-related pathologies in neonates and transplant patients.
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Bruce K, Ma J, Lawler C, Xie W, Stevenson PG, Farrell HE. Recent Advancements in Understanding Primary Cytomegalovirus Infection in a Mouse Model. Viruses 2022; 14:v14091934. [PMID: 36146741 PMCID: PMC9505653 DOI: 10.3390/v14091934] [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: 08/16/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
Animal models that mimic human infections provide insights in virus–host interplay; knowledge that in vitro approaches cannot readily predict, nor easily reproduce. Human cytomegalovirus (HCMV) infections are acquired asymptomatically, and primary infections are difficult to capture. The gap in our knowledge of the early events of HCMV colonization and spread limits rational design of HCMV antivirals and vaccines. Studies of natural infection with mouse cytomegalovirus (MCMV) have demonstrated the olfactory epithelium as the site of natural colonization. Systemic spread from the olfactory epithelium is facilitated by infected dendritic cells (DC); tracking dissemination uncovered previously unappreciated DC trafficking pathways. The olfactory epithelium also provides a unique niche that supports efficient MCMV superinfection and virus recombination. In this review, we summarize recent advances to our understanding of MCMV infection and spread and the tissue-specific mechanisms utilized by MCMV to modulate DC trafficking. As these mechanisms are likely conserved with HCMV, they may inform new approaches for preventing HCMV infections in humans.
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Abstract
CD4+ T cells are key to controlling cytomegalovirus infections. Salivary gland infection by murine cytomegalovirus (MCMV) provides a way to identify mechanisms. CD11c+ dendritic cells (DC) disseminate MCMV to the salivary glands, where they transfer infection to acinar cells. Antiviral CD4+ T cells are often considered to be directly cytotoxic for cells expressing major histocompatibility complex class II (MHCII). However, persistently infected salivary gland acinar cells are MHCII- and are presumably inaccessible to direct CD4 T cell recognition. Here, we show that CD4+ T cell depletion amplified infection of MHCII- acinar cells but not MHCII+ cells. MCMV-infected mice with disrupted MHCII on CD11c+ cells showed increased MHCII- acinar infection; antiviral CD4+ T cells were still primed, but their recruitment to the salivary glands was reduced, suggesting that engagement with local MHCII+ DC is important for antiviral protection. As MCMV downregulates MHCII on infected DC, the DC participating in CD4 protection may thus be uninfected. NK cells and gamma interferon (IFN-γ) may also contribute to CD4+ T cell-dependent virus control: CD4 T cell depletion reduced NK cell recruitment to the salivary glands, and both NK cell and IFN-γ depletion equalized infection between MHCII-disrupted and control mice. Taken together, these results suggest that CD4+ T cells protect indirectly against infected acinar cells in the salivary gland via DC engagement, requiring the recruitment of NK cells and the action of IFN-γ. Congruence of these results with an established CD4+ T cell/NK cell axis of gammaherpesvirus infection control suggests a common mode of defense against evasive viruses. IMPORTANCE Cytomegalovirus infections commonly cause problems in immunocompromised patients and in pregnancy. We lack effective vaccines. CD4+ T cells play an important role in normal infection control, yet how they act has been unknown. Using murine cytomegalovirus as an accessible model, we show that CD4+ T cells are unlikely to recognize infected cells directly. We propose that CD4+ T cells interact with uninfected cells that present viral antigens and recruit other immune cells to attack infected targets. These data present a new outlook on understanding how CD4+ T cell-directed control protects against persistent cytomegalovirus infection.
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The mouse cytomegalovirus G protein-coupled receptor homolog, M33, coordinates key features of in vivo infection via distinct components of its signalling repertoire. J Virol 2021; 96:e0186721. [PMID: 34878888 DOI: 10.1128/jvi.01867-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Common to all cytomegalovirus (CMV) genomes analysed to date is the presence of G protein-coupled receptors (GPCR). Animal models of CMV provide insights into their role in viral fitness. The mouse cytomegalovirus (MCMV) GPCR, M33, facilitates dendritic cell (DC)-dependent viremia, the extravasation of blood-borne infected DC to the salivary gland and the frequency of reactivation events from latently-infected tissue explants. Constitutive G protein-coupled M33 signalling is required for these phenotypes, although the contribution of distinct biochemical pathways activated by M33 is unknown. M33 engages Gq/11 to constitutively activate phospholipase C β (PLCβ) and downstream cyclic AMP response-element binding protein (CREB) in vitro. Identification of a MCMV M33 mutant (M33ΔC38) for which CREB signalling was disabled, but PLCβ activation was preserved, provided the opportunity to investigate their relevance in vivo. Following intranasal infection with MCMV M33ΔC38, the absence of M33 CREB Gq/11-dependent signalling correlated with reduced mobilisation of lytically-infected DC to draining lymph node high endothelial venules (HEVs) and reduced viremia compared with wild type MCMV. In contrast, M33ΔC38-infected DC within the vascular compartment extravasated to the salivary glands via a pertussis toxin-sensitive, Gi/o-dependent and CREB-independent mechanism. In the context of MCMV latency, spleen explants from M33ΔC38-infected mice were markedly attenuated for reactivation. Taken together, these data demonstrate that key features of the MCMV lifecycle are coordinated in diverse tissues by distinct pathways of the M33 signalling repertoire. IMPORTANCE G protein-coupled receptors (GPCRs) act as cell surface molecular "switches" which regulate the cellular response to environmental stimuli. All cytomegalovirus (CMV) genomes analysed to date possess GPCR homologs with phylogenetic evidence for independent gene capture events, signifying important in vivo roles. The mouse CMV (MCMV) GPCR homolog, designated M33, is important for cell-associated virus spread and for the establishment and/or reactivation of latent MCMV infection. The signalling repertoire of M33 is distinct from cellular GPCRs and little is known of the relevance of component signalling pathways for in vivo M33 function. In this report, we show temporal and tissue-specific M33 signalling is required facilitating in vivo infection. Understanding the relevance of the viral GPCR signalling profiles for in vivo function will provide opportunities for future targeted interventions.
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Mandal P, Nagrani LN, Hernandez L, McCormick AL, Dillon CP, Koehler HS, Roback L, Alnemri ES, Green DR, Mocarski ES. Multiple Autonomous Cell Death Suppression Strategies Ensure Cytomegalovirus Fitness. Viruses 2021; 13:v13091707. [PMID: 34578288 PMCID: PMC8473406 DOI: 10.3390/v13091707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/13/2021] [Accepted: 08/20/2021] [Indexed: 12/31/2022] Open
Abstract
Programmed cell death pathways eliminate infected cells and regulate infection-associated inflammation during pathogen invasion. Cytomegaloviruses encode several distinct suppressors that block intrinsic apoptosis, extrinsic apoptosis, and necroptosis, pathways that impact pathogenesis of this ubiquitous herpesvirus. Here, we expanded the understanding of three cell autonomous suppression mechanisms on which murine cytomegalovirus relies: (i) M38.5-encoded viral mitochondrial inhibitor of apoptosis (vMIA), a BAX suppressor that functions in concert with M41.1-encoded viral inhibitor of BAK oligomerization (vIBO), (ii) M36-encoded viral inhibitor of caspase-8 activation (vICA), and (iii) M45-encoded viral inhibitor of RIP/RHIM activation (vIRA). Following infection of bone marrow-derived macrophages, the virus initially deflected receptor-interacting protein kinase (RIPK)3-dependent necroptosis, the most potent of the three cell death pathways. This process remained independent of caspase-8, although suppression of this apoptotic protease enhances necroptosis in most cell types. Second, the virus deflected TNF-mediated extrinsic apoptosis, a pathway dependent on autocrine TNF production by macrophages that proceeds independently of mitochondrial death machinery or RIPK3. Third, cytomegalovirus deflected BCL-2 family protein-dependent mitochondrial cell death through combined TNF-dependent and -independent signaling even in the absence of RIPK1, RIPK3, and caspase-8. Furthermore, each of these cell death pathways dictated a distinct pattern of cytokine and chemokine activation. Therefore, cytomegalovirus employs sequential, non-redundant suppression strategies to specifically modulate the timing and execution of necroptosis, extrinsic apoptosis, and intrinsic apoptosis within infected cells to orchestrate virus control and infection-dependent inflammation. Virus-encoded death suppressors together hold control over an intricate network that upends host defense and supports pathogenesis in the intact mammalian host.
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Affiliation(s)
- Pratyusha Mandal
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
- Correspondence: (P.M.); (E.S.M.); Tel.: +404-727-0563 (P.M.); +404-727-4273 (E.S.M.)
| | | | - Liliana Hernandez
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
| | | | | | - Heather S. Koehler
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
| | - Linda Roback
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
| | - Emad S. Alnemri
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA;
| | - Douglas R. Green
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA;
| | - Edward S. Mocarski
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
- Correspondence: (P.M.); (E.S.M.); Tel.: +404-727-0563 (P.M.); +404-727-4273 (E.S.M.)
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