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Modulation of microRNome by Human Cytomegalovirus and Human Herpesvirus 6 Infection in Human Dermal Fibroblasts: Possible Significance in the Induction of Fibrosis in Systemic Sclerosis. Cells 2021; 10:cells10051060. [PMID: 33946985 PMCID: PMC8146000 DOI: 10.3390/cells10051060] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023] Open
Abstract
Human cytomegalovirus (HCMV) and Human herpesvirus 6 (HHV-6) have been reportedly suggested as triggers of the onset and/or progression of systemic sclerosis (SSc), a severe autoimmune disorder characterized by multi-organ fibrosis. The etiology and pathogenesis of SSc are still largely unknown but virological and immunological observations support a role for these beta-herpesviruses, and we recently observed a direct impact of HCMV and HHV-6 infection on the expression of cell factors associated with fibrosis at the cell level. Since miRNA expression has been found profoundly deregulated at the tissue level, here we aimed to investigate the impact on cell microRNome (miRNome) of HCMV and HHV-6 infection in in vitro infected primary human dermal fibroblasts, which represent one of the main SSc target cells. The analysis, performed by Taqman arrays detecting and quantifying 754 microRNAs (miRNAs), showed that both herpesviruses significantly modulated miRNA expression in infected cells, with evident early and late effects and deep modulation (>10 fold) of >40 miRNAs at each time post infection, including those previously recognized for their key function in fibrosis. The correlation between these in vitro results with in vivo observations is strongly suggestive of a role of HCMV and/or HHV-6 in the multistep pathogenesis of fibrosis in SSc and in the induction of fibrosis-signaling pathways finally leading to tissue fibrosis. The identification of specific miRNAs may open the way to their use as biomarkers for SSc diagnosis, assessment of disease progression and possible antifibrotic therapies.
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Human Cytomegalovirus Envelope Protein gpUL132 Regulates Infectious Virus Production through Formation of the Viral Assembly Compartment. mBio 2020; 11:mBio.02044-20. [PMID: 32994323 PMCID: PMC7527726 DOI: 10.1128/mbio.02044-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Following infection of permissive cells, human cytomegalovirus (HCMV) induces the reorganization of intracellular membranes resulting in the formation of a distinctive membranous compartment in the cytoplasm of infected cells. This compartment has been designated the viral assembly compartment (AC) and is thought to be a site for cytoplasmic virion assembly and envelopment. In this study, we have demonstrated that a single virion envelope glycoprotein is essential for AC formation in infected cells, and in its absence, there is a significant decrease in the production of infectious virions. These findings are consistent with those from other studies that have demonstrated the importance of host cell proteins in the formation of the AC and demonstrate a critical role of a single virion protein in AC formation and the efficient assembly of infectious virus. The human cytomegalovirus (HCMV) UL132 open reading frame encodes a 270-amino-acid type I envelope glycoprotein, gpUL132. The deletion of UL132 (ΔUL132) from the HCMV genome results in a pronounced deficit in virus yield, with an approximately 2-log decrease in the production of infectious virus compared to the wild-type (WT) virus. Characterization of the ΔUL132 mutant virus indicated that it was less infectious with a high particle-to-infectious unit ratio and an altered composition of virion proteins compared to the WT virus. In addition, the viral assembly compartment (AC) failed to form in cells infected with the ΔUL132 mutant virus. The expression of gpUL132 in trans rescued the defects in the morphogenesis of the AC in cells infected with the ΔUL132 mutant virus and in infectious virus production. Furthermore, using cell lines expressing chimeric proteins, we demonstrated that the cytosolic domain of gpUL132 was sufficient to rescue AC formation and WT levels of virus production. Progeny virions from ΔUL132-infected cells expressing the cytosolic domain of gpUL132 exhibited particle-to-infectious unit ratios similar to those of the WT virus. Together, our findings argue that gpUL132 is essential for HCMV AC formation and the efficient production of infectious particles, thus highlighting the importance of this envelope protein for the virus-induced reorganization of intracellular membranes and AC formation in the assembly of infectious virus.
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Arcangeletti MC, D’Accolti M, Maccari C, Soffritti I, Conto FD, Chezzi C, Calderaro A, Ferri C, Caselli E. Impact of Human Cytomegalovirus and Human Herpesvirus 6 Infection on the Expression of Factors Associated with Cell Fibrosis and Apoptosis: Clues for Implication in Systemic Sclerosis Development. Int J Mol Sci 2020; 21:E6397. [PMID: 32899126 PMCID: PMC7504027 DOI: 10.3390/ijms21176397] [Citation(s) in RCA: 12] [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: 07/29/2020] [Revised: 08/26/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023] Open
Abstract
Systemic sclerosis (SSc) is a severe autoimmune disorder characterized by vasculopathy and multi-organ fibrosis; its etiology and pathogenesis are still largely unknown. Herpesvirus infections, particularly by human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6), have been suggested among triggers of the disease based on virological and immunological observations. However, the direct impact of HCMV and/or HHV-6 infection on cell fibrosis and apoptosis at the cell microenvironment level has not yet been clarified. Thus, this study aimed to investigate the effects of HCMV and HHV-6 infection on the induction of pro-fibrosis or pro-apoptosis conditions in primary human dermal fibroblasts, one of the relevant SSc target cells. The analysis, performed by microarray in in vitro HCMV- or HHV-6-infected vs. uninfected cells, using specific panels for the detection of the main cellular factors associated with fibrosis or apoptosis, showed that both viruses significantly modified the expression of at least 30 pro-fibrotic and 20 pro-apoptotic factors. Notably, several recognized pro-fibrotic factors were highly induced, and most of them were reported to be involved in vivo in the multifactorial and multistep pathogenic process of SSc, thus suggesting a potential role of both HCMV and HHV-6.
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Affiliation(s)
- Maria-Cristina Arcangeletti
- Department of Medicine and Surgery, Unit of Virology, University-Hospital of Parma, University of Parma, 43126 Parma, Italy; (C.M.); (F.D.C.); (C.C.); (A.C.)
| | - Maria D’Accolti
- Department of Chemical and Pharmaceutical Sciences, Section of Microbiology and Medical Genetics, University of Ferrara, 44121 Ferrara, Italy; (M.D.); (I.S.); (E.C.)
| | - Clara Maccari
- Department of Medicine and Surgery, Unit of Virology, University-Hospital of Parma, University of Parma, 43126 Parma, Italy; (C.M.); (F.D.C.); (C.C.); (A.C.)
| | - Irene Soffritti
- Department of Chemical and Pharmaceutical Sciences, Section of Microbiology and Medical Genetics, University of Ferrara, 44121 Ferrara, Italy; (M.D.); (I.S.); (E.C.)
| | - Flora De Conto
- Department of Medicine and Surgery, Unit of Virology, University-Hospital of Parma, University of Parma, 43126 Parma, Italy; (C.M.); (F.D.C.); (C.C.); (A.C.)
| | - Carlo Chezzi
- Department of Medicine and Surgery, Unit of Virology, University-Hospital of Parma, University of Parma, 43126 Parma, Italy; (C.M.); (F.D.C.); (C.C.); (A.C.)
| | - Adriana Calderaro
- Department of Medicine and Surgery, Unit of Virology, University-Hospital of Parma, University of Parma, 43126 Parma, Italy; (C.M.); (F.D.C.); (C.C.); (A.C.)
| | - Clodoveo Ferri
- Department of Medical and Surgical Sciences for Children and Adults, Rheumatology Unit, University-Hospital Policlinico of Modena, University of Modena and Reggio Emilia, 41121 Modena, Italy;
| | - Elisabetta Caselli
- Department of Chemical and Pharmaceutical Sciences, Section of Microbiology and Medical Genetics, University of Ferrara, 44121 Ferrara, Italy; (M.D.); (I.S.); (E.C.)
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Abstract
The nucleolus is a prominent subnuclear compartment, where ribosome biosynthesis takes place. Recently, the nucleolus has gained attention for its novel role in the regulation of cellular stress. Nucleolar stress is emerging as a new concept, which is characterized by diverse cellular insult-induced abnormalities in nucleolar structure and function, ultimately leading to activation of p53 or other stress signaling pathways and alterations in cell behavior. Despite a number of comprehensive reviews on this concept, straightforward and clear-cut way criteria for a nucleolar stress state, regarding the factors that elicit this state, the morphological and functional alterations as well as the rationale for p53 activation are still missing. Based on literature of the past two decades, we herein summarize the evolution of the concept and provide hallmarks of nucleolar stress. Along with updated information and thorough discussion of existing confusions in the field, we pay particular attention to the current understanding of the sensing mechanisms, i.e., how stress is integrated by p53. In addition, we propose our own emphasis regarding the role of nucleolar protein NPM1 in the hallmarks of nucleolar stress and sensing mechanisms. Finally, the links of nucleolar stress to human diseases are briefly and selectively introduced.
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Affiliation(s)
- Kai Yang
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China.,Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
| | - Jie Yang
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China
| | - Jing Yi
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China
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Kostopoulou ON, Wilhelmi V, Raiss S, Ananthaseshan S, Lindström MS, Bartek J, Söderberg-Naucler C. Human cytomegalovirus and Herpes Simplex type I virus can engage RNA polymerase I for transcription of immediate early genes. Oncotarget 2017; 8:96536-96552. [PMID: 29228551 PMCID: PMC5722503 DOI: 10.18632/oncotarget.22106] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 10/13/2017] [Indexed: 12/22/2022] Open
Abstract
Human cytomegalovirus (HCMV) utilizes RNA polymerase II to transcribe viral genes and produce viral mRNAs. It can specifically target the nucleolus to facilitate viral transcription and translation. As RNA polymerase I (Pol I)-mediated transcription is active in the nucleolus, we investigated the role of Pol I, along with relative contributions of the human Pol II and Pol III, to early phases of viral transcription in HCMV infected cells, compared with Herpes Simplex Virus-1 (HSV-1) and Murine cytomegalovirus (MCMV). Inhibition of Pol I with siRNA or the Pol I inhibitors CX-5461 or Actinomycin D (5nM) resulted in significantly decreased IE and pp65 mRNA and protein levels in human fibroblasts at early times post infection. This initially delayed replication was compensated for later during the replication process, at which stage it didn't significantly affect virus production. Pol I inhibition also reduced HSV-1 ICP0 and gB transcripts, suggesting that some herpesviruses engage Pol I for their early transcription. In contrast, inhibition of Pol I failed to affect MCMV transcription. Collectively, our results contribute to better understanding of the functional interplay between RNA Pol I-mediated nucleolar events and the Herpes viruses, particularly HCMV whose pathogenic impact ranges from congenital malformations and potentially deadly infections among immunosuppressed patients, up to HCMV's emerging oncomodulatory role in human tumors.
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Affiliation(s)
- Ourania N Kostopoulou
- Department of Medicine, Center for Molecular Medicine L8:03, Karolinska University Hospital, Stockholm, Sweden
| | - Vanessa Wilhelmi
- Department of Medicine, Center for Molecular Medicine L8:03, Karolinska University Hospital, Stockholm, Sweden
| | - Sina Raiss
- Department of Medicine, Center for Molecular Medicine L8:03, Karolinska University Hospital, Stockholm, Sweden
| | - Sharan Ananthaseshan
- Department of Medicine, Center for Molecular Medicine L8:03, Karolinska University Hospital, Stockholm, Sweden
| | - Mikael S Lindström
- Department of Medical Biochemistry and Biophysics, Science For Life Laboratory, Division of Genome Biology, Karolinska Institute, Solna, Sweden
| | - Jiri Bartek
- Department of Medical Biochemistry and Biophysics, Science For Life Laboratory, Division of Genome Biology, Karolinska Institute, Solna, Sweden
| | - Cecilia Söderberg-Naucler
- Department of Medicine, Center for Molecular Medicine L8:03, Karolinska University Hospital, Stockholm, Sweden
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Cytomegalovirus Late Protein pUL31 Alters Pre-rRNA Expression and Nuclear Organization during Infection. J Virol 2017; 91:JVI.00593-17. [PMID: 28659485 DOI: 10.1128/jvi.00593-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/24/2017] [Indexed: 02/01/2023] Open
Abstract
The replication cycle of human cytomegalovirus (CMV) leads to drastic reorganization of domains in the host cell nucleus. However, the mechanisms involved and how these domains contribute to infection are not well understood. Our recent studies defining the CMV-induced nuclear proteome identified several viral proteins of unknown functions, including a protein encoded by the UL31 gene. We set out to define the role of UL31 in CMV replication. UL31 is predicted to encode a 74-kDa protein, referred to as pUL31, containing a bipartite nuclear localization signal, an intrinsically disordered region overlapping arginine-rich motifs, and a C-terminal dUTPase-like structure. We observed that pUL31 is expressed with true late kinetics and is localized to nucleolin-containing nuclear domains. However, pUL31 is excluded from the viral nuclear replication center. Nucleolin is a marker of nucleoli, which are membrane-less regions involved in regulating ribosome biosynthesis and cellular stress responses. Other CMV proteins associate with nucleoli, and we demonstrate that pUL31 specifically interacts with the viral protein, pUL76. Coexpression of both proteins altered pUL31 localization and nucleolar organization. During infection, pUL31 colocalizes with nucleolin but not the transcriptional activator, UBF. In the absence of pUL31, CMV fails to reorganize nucleolin and UBF and exhibits a replication defect at a low multiplicity of infection. Finally, we observed that pUL31 is necessary and sufficient to reduce pre-rRNA levels, and this was dependent on the dUTPase-like motif in pUL31. Our studies demonstrate that CMV pUL31 functions in regulating nucleolar biology and contributes to the reorganization of nucleoli during infection.IMPORTANCE Nucleolar biology is important during CMV infection with the nucleolar protein, with nucleolin playing a role in maintaining the architecture of the viral nuclear replication center. However, the extent of CMV-mediated regulation of nucleolar biology is not well established. Proteins within nucleoli regulate ribosome biosynthesis and p53-dependent cellular stress responses that are capable of inducing cell cycle arrest and/or apoptosis, and they are proposed targets for cancer therapies. This study establishes that CMV protein pUL31 is necessary and sufficient to regulate nucleolar biology involving the reorganization of nucleolar proteins. Understanding these processes will help define approaches to stimulate cellular intrinsic stress responses that are capable of inhibiting CMV infection.
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Arcangeletti MC, Vasile Simone R, Rodighiero I, De Conto F, Medici MC, Maccari C, Chezzi C, Calderaro A. Human cytomegalovirus reactivation from latency: validation of a "switch" model in vitro. Virol J 2016; 13:179. [PMID: 27770817 PMCID: PMC5075216 DOI: 10.1186/s12985-016-0634-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 10/10/2016] [Indexed: 02/07/2023] Open
Abstract
Background Human cytomegalovirus (HCMV) is an opportunistic pathogen leading to severe and even fatal diseases in ‘at-risk’ categories of individuals upon primary infection or the symptomatic reactivation of the endogenous virus. The mechanisms which make the virus able to reactivate from latency are still matter of intense study. However, the very low number of peripheral blood monocytes (an important latent virus reservoir) harbouring HCMV DNA makes it very difficult to obtain adequate viral quantities to use in such studies. Thus, the aim of the present study was to demonstrate the usefulness of human THP-1 monocytes, mostly employed as HCMV latent or lytic infection system, as a reactivation model. Methods THP-1 monocytes were infected with HCMV TB40E strain (latency model) at multiplicities of infection (MOI) of 0.5, 0.25 or 0.125. After infection, THP-1 aliquots were differentiated into macrophages (reactivation model). Infections were carried out for 30 h, 4, 6 and 7 days. Viral DNA evaluation was performed with viable and UV-inactivated virus by q-Real-Time PCR. RNA extracted from latency and reactivation models at 7 days post-infection (p.i.) was subjected to RT-PCR to analyse viral latency and lytic transcripts. To perform viral progeny analysis and titration, the culture medium from infected THP-1 latency and reactivation models (7 days p.i.) was used to infect human fibroblasts; it was also checked for the presence of exosomes. For viral progeny analysis experiments, the Towne strain was also used. Results Our results showed that, while comparable TB40E DNA amounts were present in both latent and reactivation models at 30 h p.i., gradually increased quantities of viral DNA were only evident in the latter model at 4, 6, 7 days p.i.. The completion of the lytic cycle upon reactivation was also proved by the presence of HCMV lytic transcripts and an infectious viral yield at 7 days p.i. Conclusions Our data demonstrate the effectiveness of THP-1 cells as a “switch” model for studying the mechanisms that regulate HCMV reactivation from latency. This system is able to provide adequate quantities of cells harbouring latent/reactivated virus, thereby overcoming the intrinsic difficulties connected to the ex vivo system. Electronic supplementary material The online version of this article (doi:10.1186/s12985-016-0634-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maria-Cristina Arcangeletti
- Department of Clinical and Experimental Medicine, Unit of Microbiology and Virology, University of Parma, Viale A. Gramsci, 14, Parma, 43126, Italy.
| | - Rosita Vasile Simone
- Department of Clinical and Experimental Medicine, Unit of Microbiology and Virology, University of Parma, Viale A. Gramsci, 14, Parma, 43126, Italy
| | - Isabella Rodighiero
- Department of Clinical and Experimental Medicine, Unit of Microbiology and Virology, University of Parma, Viale A. Gramsci, 14, Parma, 43126, Italy
| | - Flora De Conto
- Department of Clinical and Experimental Medicine, Unit of Microbiology and Virology, University of Parma, Viale A. Gramsci, 14, Parma, 43126, Italy
| | - Maria-Cristina Medici
- Department of Clinical and Experimental Medicine, Unit of Microbiology and Virology, University of Parma, Viale A. Gramsci, 14, Parma, 43126, Italy
| | - Clara Maccari
- Department of Clinical and Experimental Medicine, Unit of Microbiology and Virology, University of Parma, Viale A. Gramsci, 14, Parma, 43126, Italy
| | - Carlo Chezzi
- Department of Clinical and Experimental Medicine, Unit of Microbiology and Virology, University of Parma, Viale A. Gramsci, 14, Parma, 43126, Italy
| | - Adriana Calderaro
- Department of Clinical and Experimental Medicine, Unit of Microbiology and Virology, University of Parma, Viale A. Gramsci, 14, Parma, 43126, Italy
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Soroceanu L, Matlaf L, Khan S, Akhavan A, Singer E, Bezrookove V, Decker S, Ghanny S, Hadaczek P, Bengtsson H, Ohlfest J, Luciani-Torres MG, Harkins L, Perry A, Guo H, Soteropoulos P, Cobbs CS. Cytomegalovirus Immediate-Early Proteins Promote Stemness Properties in Glioblastoma. Cancer Res 2015; 75:3065-76. [PMID: 26239477 DOI: 10.1158/0008-5472.can-14-3307] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glioblastoma (GBM) is the most common and aggressive human brain tumor. Human cytomegalovirus (HCMV) immediate-early (IE) proteins that are endogenously expressed in GBM cells are strong viral transactivators with oncogenic properties. Here, we show how HCMV IEs are preferentially expressed in glioma stem-like cells (GSC), where they colocalize with the other GBM stemness markers, CD133, Nestin, and Sox2. In patient-derived GSCs that are endogenously infected with HCMV, attenuating IE expression by an RNAi-based strategy was sufficient to inhibit tumorsphere formation, Sox2 expression, cell-cycle progression, and cell survival. Conversely, HCMV infection of HMCV-negative GSCs elicited robust self-renewal and proliferation of cells that could be partially reversed by IE attenuation. In HCMV-positive GSCs, IE attenuation induced a molecular program characterized by enhanced expression of mesenchymal markers and proinflammatory cytokines, resembling the therapeutically resistant GBM phenotype. Mechanistically, HCMV/IE regulation of Sox2 occurred via inhibition of miR-145, a negative regulator of Sox2 protein expression. In a spontaneous mouse model of glioma, ectopic expression of the IE1 gene (UL123) specifically increased Sox2 and Nestin levels in the IE1-positive tumors, upregulating stemness and proliferation markers in vivo. Similarly, human GSCs infected with the HCMV strain Towne but not the IE1-deficient strain CR208 showed enhanced growth as tumorspheres and intracranial tumor xenografts, compared with mock-infected human GSCs. Overall, our findings offer new mechanistic insights into how HCMV/IE control stemness properties in GBM cells.
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Affiliation(s)
- Liliana Soroceanu
- Department of Neurosciences, California Pacific Medical Center Research Institute, San Francisco, California.
| | - Lisa Matlaf
- Department of Neurosciences, California Pacific Medical Center Research Institute, San Francisco, California
| | - Sabeena Khan
- Department of Neurosciences, California Pacific Medical Center Research Institute, San Francisco, California
| | - Armin Akhavan
- Department of Neurosciences, California Pacific Medical Center Research Institute, San Francisco, California
| | - Eric Singer
- Department of Neurosciences, California Pacific Medical Center Research Institute, San Francisco, California
| | - Vladimir Bezrookove
- Department of Neurosciences, California Pacific Medical Center Research Institute, San Francisco, California
| | - Stacy Decker
- Department of Pediatrics and Neurosurgery, University of Minnesota Masonic Cancer Center, Minneapolis, Minnesota
| | - Saleena Ghanny
- Center for Applied Genomics, Institute of Genomic Medicine, University of Medicine and Dentistry of New Jersey, Newark, New Jersey
| | - Piotr Hadaczek
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
| | - Henrik Bengtsson
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California
| | - John Ohlfest
- Department of Pediatrics and Neurosurgery, University of Minnesota Masonic Cancer Center, Minneapolis, Minnesota
| | - Maria-Gloria Luciani-Torres
- Department of Neurosciences, California Pacific Medical Center Research Institute, San Francisco, California
| | - Lualhati Harkins
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Arie Perry
- Department of Pathology, University of California, San Francisco, California
| | - Hong Guo
- Center for Applied Genomics, Institute of Genomic Medicine, University of Medicine and Dentistry of New Jersey, Newark, New Jersey
| | - Patricia Soteropoulos
- Center for Applied Genomics, Institute of Genomic Medicine, University of Medicine and Dentistry of New Jersey, Newark, New Jersey
| | - Charles S Cobbs
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California. Ben and Catherine Ivy Center for Advanced Brain Tumor Treatment, Seattle, Washington.
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Dynamic and nucleolin-dependent localization of human cytomegalovirus UL84 to the periphery of viral replication compartments and nucleoli. J Virol 2014; 88:11738-47. [PMID: 25078694 DOI: 10.1128/jvi.01889-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protein-protein and protein-nucleic acid interactions within subcellular compartments are required for viral genome replication. To understand the localization of the human cytomegalovirus viral replication factor UL84 relative to other proteins involved in viral DNA synthesis and to replicating viral DNA in infected cells, we created a recombinant virus expressing a FLAG-tagged version of UL84 (UL84FLAG) and used this virus in immunofluorescence assays. UL84FLAG localization differed at early and late times of infection, transitioning from diffuse distribution throughout the nucleus to exclusion from the interior of replication compartments, with some concentration at the periphery of replication compartments with newly labeled DNA and the viral DNA polymerase subunit UL44. Early in infection, UL84FLAG colocalized with the viral single-stranded DNA binding protein UL57, but colocalization became less prominent as infection progressed. A portion of UL84FLAG also colocalized with the host nucleolar protein nucleolin at the peripheries of both replication compartments and nucleoli. Small interfering RNA (siRNA)-mediated knockdown of nucleolin resulted in a dramatic elimination of UL84FLAG from replication compartments and other parts of the nucleus and its accumulation in the cytoplasm. Reciprocal coimmunoprecipitation of viral proteins from infected cell lysates revealed association of UL84, UL44, and nucleolin. These results indicate that UL84 localization during infection is dynamic, which is likely relevant to its functions, and suggest that its nuclear and subnuclear localization is highly dependent on direct or indirect interactions with nucleolin. Importance: The protein-protein interactions among viral and cellular proteins required for replication of the human cytomegalovirus (HCMV) DNA genome are poorly understood. We sought to understand how an enigmatic HCMV protein critical for virus replication, UL84, localizes relative to other viral and cellular proteins required for HCMV genome replication and replicating viral DNA. We found that UL84 localizes with viral proteins, viral DNA, and the cellular nucleolar protein nucleolin in the subnuclear replication compartments in which viral DNA replication occurs. Unexpectedly, we also found localization of UL84 with nucleolin in nucleoli and showed that the presence of nucleolin is involved in localization of UL84 to the nucleus. These results add to previous work showing the importance of nucleolin in replication compartment architecture and viral DNA synthesis and are relevant to understanding UL84 function.
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Arcangeletti MC, Germini D, Rodighiero I, Mirandola P, De Conto F, Medici MC, Gatti R, Chezzi C, Calderaro A. Toll-like receptor 4 is involved in the cell cycle modulation and required for effective human cytomegalovirus infection in THP-1 macrophages. Virology 2013; 440:19-30. [PMID: 23497941 DOI: 10.1016/j.virol.2013.01.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 11/06/2012] [Accepted: 01/28/2013] [Indexed: 11/30/2022]
Abstract
Suitable host cell metabolic conditions are fundamental for the effective development of the human cytomegalovirus (HCMV) lytic cycle. Indeed, several studies have demonstrated the ability of this virus to interfere with cell cycle regulation, mainly by blocking proliferating cells in G1 or G1/S. In the present study, we demonstrate that HCMV deregulates the cell cycle of THP-1 macrophages (a cell line irreversibly arrested in G0) by pushing them into S and G2 phases. Moreover, we show that HCMV infection of THP-1 macrophages leads to Toll-like receptor 4 (TLR4) activation. Since various studies have indicated TLR4 to be involved in promoting cell proliferation, here we investigate the possible role of TLR4 in the observed HCMV-induced cell cycle perturbation. Our data strongly support TLR4 as a mediator of HCMV-triggered cell cycle activation in THP-1 macrophages favouring, in turn, the development of an efficient viral lytic cycle.
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11
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Gill RB, James SH, Prichard MN. Human cytomegalovirus UL97 kinase alters the accumulation of CDK1. J Gen Virol 2012; 93:1743-1755. [PMID: 22552942 PMCID: PMC3541764 DOI: 10.1099/vir.0.039214-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 04/30/2012] [Indexed: 12/14/2022] Open
Abstract
The UL97 protein kinase is a serine/threonine kinase expressed by human cytomegalovirus (CMV) that phosphorylates ganciclovir. An investigation of the subcellular localization of pUL97 in infected cells indicated that, early in infection, pUL97 localized to focal sites in the nucleus that transitioned to subnuclear compartments and eventually throughout the entire nucleus. When UL97 kinase activity was eliminated with a K355M mutation or pharmacologically inhibited with maribavir, the expansion and redistribution of pUL97 foci within the nucleus was delayed, nuclear reorganization did not occur and assembly complexes in the cytoplasm failed to form normally. As UL97 kinase and its homologues appear to be functionally related to CDK1, a known regulator of nuclear structural organization, the effects of the UL97 kinase on CDK1 were investigated. Expression of CDK1 in infected cells appeared to be induced by UL97 kinase activity at the level of transcription and was not tied to other virus life-cycle events, such as viral DNA replication or virion assembly. These results suggest that, in addition to phosphorylating CDK1 targets, the UL97 kinase modifies G₂/M cell-cycle checkpoint regulators, specifically CDK1, to promote virus replication.
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Affiliation(s)
- Rachel B. Gill
- Department of Cell Biology, 1900 University Blvd, Birmingham, AL 35294, USA
| | - Scott H. James
- Department of Pediatrics, University of Alabama at Birmingham, 1600 6th Avenue South, Birmingham, AL 35233, USA
| | - Mark N. Prichard
- Department of Cell Biology, 1900 University Blvd, Birmingham, AL 35294, USA
- Department of Pediatrics, University of Alabama at Birmingham, 1600 6th Avenue South, Birmingham, AL 35233, USA
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12
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Affiliation(s)
- Mark O. J. Olson
- Dept. Biochemistry, University of Mississippi Medical Center, North State St. 2500, Jackson, 39216 Mississippi USA
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Arcangeletti MC, Rodighiero I, Mirandola P, De Conto F, Covan S, Germini D, Razin S, Dettori G, Chezzi C. Cell-cycle-dependent localization of human cytomegalovirus UL83 phosphoprotein in the nucleolus and modulation of viral gene expression in human embryo fibroblasts in vitro. J Cell Biochem 2011; 112:307-17. [PMID: 21053310 DOI: 10.1002/jcb.22928] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The nucleolus is a multifunctional nuclear compartment widely known to be involved in several cellular processes, including mRNA maturation and shuttling to cytoplasmic sites, control of the cell cycle, cell proliferation, and apoptosis; thus, it is logical that many viruses, including herpesvirus, target the nucleolus in order to exploit at least one of the above-mentioned functions. Recent studies from our group demonstrated the early accumulation of the incoming ppUL83 (pp65), the major tegument protein of human cytomegalovirus (HCMV), in the nucleolus. The obtained results also suggested that a functional relationship might exist between the nucleolar localization of pp65, rRNA synthesis, and the development of the lytic program of viral gene expression. Here we present new data which support the hypothesis of a potentially relevant role of HCMV pp65 and its nucleolar localization for the control of the cell cycle by HCMV (arrest of cell proliferation in G1-G1/S), and for the promotion of viral infection. We demonstrated that, although the incoming pp65 amount in the infected cells appears to be constant irrespective of the cell-cycle phase, its nucleolar accumulation is prominent in G1 and G1/S, but very poor in S or G2/M. This correlates with the observation that only cells in G1 and G1/S support an efficient development of the HCMV lytic cycle. We propose that HCMV pp65 might be involved in regulatory/signaling pathways related to nucleolar functions, such as the cell-cycle control. Co-immunoprecipitation experiments have permitted to identify nucleolin as one of the nucleolar partners of pp65.
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Human cytomegalovirus pUL83 stimulates activity of the viral immediate-early promoter through its interaction with the cellular IFI16 protein. J Virol 2010; 84:7803-14. [PMID: 20504932 DOI: 10.1128/jvi.00139-10] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The human cytomegalovirus (HCMV) virion protein pUL83 (also termed pp65) inhibits the expression of interferon-inducible cellular genes. In this work we demonstrate that pUL83 is also important for efficient induction of transcription from the viral major immediate-early promoter. Infection with a mutant virus containing a premature translation termination codon in the UL83 open reading frame (ORF) (UL83Stop) resulted in decreased transcription from the major immediate-early promoter in a time- and multiplicity-dependent manner. Expression of pUL83 alone is capable of transactivating the promoter in a reporter assay, and pUL83 associates with the promoter in infected cells. To investigate the mechanism by which the protein regulates the major immediate-early promoter, we utilized a mutant virus expressing an epitope-tagged pUL83 from its own promoter to identify protein binding partners for pUL83 during infection. We identified and confirmed the interaction of pUL83 with cellular IFI16 family members throughout the course of HCMV infection. pUL83 recruits IFI16 to the major immediate-early promoter, and IFI16 binding at the promoter is dependent upon the presence of pUL83. Consistent with the results obtained with the UL83Stop virus, infection of IFI16 knockdown cells with wild-type virus resulted in decreased levels of immediate-early transcripts compared to those of control cells. These data identify a previously unknown role for pUL83 in the initiation of the human cytomegalovirus gene expression cascade.
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Arcangeletti MC, Rodighiero I, De Conto F, Gatti R, Orlandini G, Ferraglia F, Motta F, Covan S, Razin SV, Dettori G, Chezzi C. Modulatory effect of rRNA synthesis and ppUL83 nucleolar compartmentalization on human cytomegalovirus gene expression in vitro. J Cell Biochem 2009; 108:415-23. [PMID: 19585527 PMCID: PMC7167110 DOI: 10.1002/jcb.22268] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The nucleolus is a nuclear domain involved in the biogenesis of ribosomes, as well as in many other important cellular regulatory activities, such as cell cycle control and mRNA processing. Many viruses, including herpesviruses, are known to exploit the nucleolar compartment during their replication cycle. In a previous study, we demonstrated the preferential targeting and accumulation of the human cytomegalovirus (HCMV) UL83 phosphoprotein (pp65) to the nucleolar compartment and, in particular, to the nucleolar matrix of lytically infected fibroblasts; such targeting was already evident at very early times after infection. Here we have investigated the possible effects of rRNA synthesis inhibition upon the development of HCMV lytic infection, by using either actinomycin D or cisplatin at low concentrations, that are known to selectively inhibit RNA polymerase I activity, whilst leaving RNA polymerase II function unaffected. Following the inhibition of rRNA synthesis by either of the agents used, we observed a significant redistribution of nucleolar proteins within the nucleoplasm and a simultaneous depletion of viral pp65 from the nucleolus; this effect was highly evident in both unextracted cells and in nuclear matrices in situ. Of particular interest, even a brief suppression of rRNA synthesis resulted in a very strong inhibition of the progression of HCMV infection, as was concluded from the absence of accumulation of HCMV major immediate‐early proteins within the nucleus of infected cells. These data suggest that a functional relationship might exist between rRNA synthesis, pp65 localization to the nucleolar matrix and the normal development of HCMV lytic infection. J. Cell. Biochem. 108: 415–423, 2009. © 2009 Wiley‐Liss, Inc.
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Abstract
Viruses are intracellular pathogens that have to usurp some of the cellular machineries to provide an optimal environment for their own replication. An increasing number of reports reveal that many viruses induce modifications of nuclear substructures including nucleoli, whether they replicate or not in the nucleus of infected cells. Indeed, during infection of cells with various types of human viruses, nucleoli undergo important morphological modifications. A large number of viral components traffic to and from the nucleolus where they interact with different cellular and/or viral factors, numerous host nucleolar proteins are redistributed in other cell compartments or are modified and some cellular proteins are delocalised in the nucleolus of infected cells. Well‐documented studies have established that several of these nucleolar modifications play a role in some steps of the viral cycle, and also in fundamental cellular pathways. The nucleolus itself is the place where several essential steps of the viral cycle take place. In other cases, viruses divert host nucleolar proteins from their known functions in order to exert new unexpected role(s). Copyright © 2009 John Wiley & Sons, Ltd.
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Affiliation(s)
- Anna Greco
- Université de Lyon, Lyon F-69003, France.
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Cui Z, Zhang K, Zhang Z, Liu Y, Zhou Y, Wei H, Zhang XE. Visualization of the dynamic multimerization of human Cytomegalovirus pp65 in punctuate nuclear foci. Virology 2009; 392:169-77. [DOI: 10.1016/j.virol.2009.06.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 04/06/2009] [Accepted: 06/11/2009] [Indexed: 11/24/2022]
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18
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Ioudinkova E, Arcangeletti MC, Rynditch A, De Conto F, Motta F, Covan S, Pinardi F, Razin SV, Chezzi C. Control of human cytomegalovirus gene expression by differential histone modifications during lytic and latent infection of a monocytic cell line. Gene 2006; 384:120-8. [PMID: 16989963 DOI: 10.1016/j.gene.2006.07.021] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 06/23/2006] [Accepted: 07/04/2006] [Indexed: 01/28/2023]
Abstract
Non-differentiated THP-1 cells can be infected by human cytomegalovirus (HCMV) Towne strain, which persists in these cells in a non-active (latent) form without undergoing a productive cycle. The same cells become permissive for HCMV lytic infection after induction of cell differentiation by treatment with 12-O-tetradecanoylphorbol-13-acetate. We used this cellular model to study the possible role of histone modifications in the control of HCMV latency. Using chromatin immunoprecipitation with antibodies against histone H3 acetylated or dimethylated in position K9, we demonstrated that in lytically infected cells the HCMV enhancer was associated with heavy acetylated but not dimethylated H3. In the case of latent infection, the HCMV enhancer was associated with neither acetylated nor dimethylated H3. HCMV genes encoding DNA polymerase (early), pp65 (early-late) and pp150 (late) proteins were associated preferentially with acetylated H3 in lytically infected cells and with dimethylated H3 in latently infected cells. These data strongly suggest that K9 methylation of H3 is involved in HCMV gene repression, while association of the above genes with acetylated histones is likely to be necessary for active transcription. It can be postulated that the same histone modifications are used to mark active and repressed genes in both cellular and viral chromatin.
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Affiliation(s)
- Elena Ioudinkova
- Microbiology Section, Department of Pathology and Laboratory Medicine, University of Parma, Viale Antonio Gramsci, 14, 43100 Parma, Italy
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Yue Y, Kaur A, Zhou SS, Barry PA. Characterization and immunological analysis of the rhesus cytomegalovirus homologue (Rh112) of the human cytomegalovirus UL83 lower matrix phosphoprotein (pp65). J Gen Virol 2006; 87:777-787. [PMID: 16528025 DOI: 10.1099/vir.0.81516-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rhesus cytomegalovirus (RhCMV) contains two open reading frames (Rh111 and Rh112) that encode proteins homologous to the phosphoprotein 65 (pp65) of the human cytomegalovirus (HCMV) UL83 gene. As HCMV pp65 elicits protective immune responses in infected humans and represents an important vaccination target, one RhCMV homologue of HCMV pp65, pp65-2 (Rh112), was characterized and analysed for its ability to induce host immune responses. Similar to its HCMV counterpart, RhCMV pp65-2 was expressed as a late gene, localized to the nucleus within pp65-2-expressing cells and was present within infectious virions. Longitudinal and cross-sectional studies of pp65-2 immunity in naturally infected rhesus macaques showed that humoral responses to pp65-2 were elicited early during infection, but were not always sustained over time. In contrast, pp65-2-specific T-cell responses, examined by gamma interferon ELISPOT, were broadly detectable in all of the animals studied during primary infection and persisted in the vast majority of RhCMV-seropositive monkeys. Moreover, there was considerable inter-animal variability in the pattern of the immune responses to pp65-2. Together, these results demonstrated that RhCMV pp65-2 exhibited biological and immunological homology to HCMV pp65. Thus, the rhesus macaque model of HCMV persistence and pathogenesis should be relevant for addressing pp65-based vaccine modalities.
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Affiliation(s)
- Yujuan Yue
- Center for Comparative Medicine, University of California, Davis, County Road 98 and Hutchison Drive, Davis, CA 95616, USA
| | - Amitinder Kaur
- Department of Immunology, New England Primate Research Center, Harvard Medical School, Southborough, MA 02129, USA
| | - Shan Shan Zhou
- Center for Comparative Medicine, University of California, Davis, County Road 98 and Hutchison Drive, Davis, CA 95616, USA
| | - Peter A Barry
- California National Primate Research Center, University of California, Davis, County Road 98 and Hutchison Drive, Davis, CA 95616, USA
- Department of Pathology and Laboratory Medicine, University of California, Davis, County Road 98 and Hutchison Drive, Davis, CA 95616, USA
- Center for Comparative Medicine, University of California, Davis, County Road 98 and Hutchison Drive, Davis, CA 95616, USA
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