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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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Chen C, Chen S, Han Z, Xie W, Zhang T, Mao C, Zhang L, Sun X, Kwok T, Shen X, Xue X. Patients with Helicobacter pylori-positive gastric cancer with human cytomegalovirus infection have a low tendency of advanced lymphatic metastasis in a Chinese population. Oncol Lett 2021; 21:402. [PMID: 33777225 PMCID: PMC7988662 DOI: 10.3892/ol.2021.12663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 07/22/2020] [Indexed: 11/18/2022] Open
Abstract
Recognized as a group I carcinogen for gastric cancer (GC) and a factor involved in the development of GC, Helicobacter pylori serves a major part in GC research. However, most studies have focused on H. pylori itself, ignoring the complicated pathogenic microbiological environment of GC and neglecting the synergistic or antagonistic effects of H. pylori with other pathogenic microorganisms. Increasing evidence has revealed that the human cytomegalovirus (HCMV) is present in several types of tumors and serves an important role in the neoplastic process of certain human malignant tumors, including GC. The aim of the present study was to explore the role of HCMV and H. pylori co-infection in GC. HCMV and H. pylori infection was analyzed in paired gastric tumor and peri-tumoral tissues from 134 (98 male and 36 female) patients using PCR. The results revealed that a total of 74 (55.2%) patients had H. pylori infection, 58 patients (43.3%) had HCMV infection, and 34 (25.4%) patients had both HCMV and H. pylori infection. Univariate and multivariate analyses demonstrated that H. pylori infection was independently associated with advanced lymphatic metastasis [P=0.007; odds ratio (OR)=3.51]. Furthermore, compared with HCMV-/H. pylori -, neither HCMV+/H. pylori - nor HCMV+/H. pylori + were associated with metastasis, but HCMV-/H. pylori + co-infection status was an independent risk factor for advanced lymphatic metastasis (P=0.005; OR=6.00). In conclusion, GC co-infected with HCMV and H. pylori exhibited a low tendency of lymph node metastasis. HCMV may interact with H. pylori to inhibit the process of lymphatic metastasis, and the mechanism requires further investigation.
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Affiliation(s)
- Chao Chen
- Department of Oncology, Wenzhou Hospital of Integrated Traditional Chinese and Western Medicine Affiliated to Zhejiang Chinese Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Sian Chen
- Department of General Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Zheng Han
- Department of General Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Wangkai Xie
- Department of General Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Teming Zhang
- Department of General Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Chenchen Mao
- Department of General Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Liang Zhang
- Department of General Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Xiangwei Sun
- Department of General Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Terry Kwok
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Melbourne, Victoria 3800, Australia
- Cancer Program, Biomedicine Discovery Institute, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
- Department of Microbiology, Monash University, Melbourne, Victoria 3800, Australia
| | - Xian Shen
- Department of General Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Xiangyang Xue
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
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Zhang X, Zhang L, Bi Y, Xi T, Zhang Z, Huang Y, Lu YY, Liu X, Shu S, Fang F. Inhibition of autophagy by 3-methyladenine restricts murine cytomegalovirus replication. J Med Virol 2021; 93:5001-5016. [PMID: 33421149 DOI: 10.1002/jmv.26787] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 01/18/2023]
Abstract
Cytomegalovirus (CMV) induced autophagy affects virus replication and survival of the infected cells. The purpose of this study was to investigate the role of autophagy inhibition by 3-methyladenine (3-MA) on murine cytomegalovirus (MCMV) replication and whether it is associated with caspase-3 dependent apoptosis. The eyecup isolated from adult C57BL/6J mice (6-8 weeks old) and mouse embryo fibroblast cells (MEFs) were infected with MCMV K181 strain, followed by the treatment of 3-methyladenine (3-MA), chloroquine, or rapamycin to block or stimulate autophagy. In cultured MEFs, the ratio of LC3I/II was reduced at 24 hours post infection (hpi), but was increased at 48 hpi In the eyecup culture, LC3I/II ratio was also decreased at 4 and 7 days post infection (dpi). In addition, caspase-3 cleavage was increased at 48 hpi in MEFs and also elevated in MCMV infected eyecups at 4, 7, 10, and 14 dpi. 3-MA treatment significantly inhibited the virus replication in MEFs and eyecups. The expression of early antigen (EA) of MCMV was also decreased in MEFs and eyecups. Meanwhile, cleaved caspase-3 dependent cell death was promoted with the presence of 3-MA in MCMV infected MEFs and eyecups, while RIPK1/RIPK3/MLKL pathway was inhibited by 3-MA in eyecups. Inhibition of autophagy by 3-MA restricts virus replication and promotes caspase-3 dependent apoptosis in the eyecup and MEFs with MCMV infection. It can be explained that during the early period of MCMV infection, the suppressed autophagy process directly reduced virus release, but later caspase-3 dependent apoptosis dominated and resulted in decreased virus replication.
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Affiliation(s)
- Xinyan Zhang
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Linlin Zhang
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yidan Bi
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ting Xi
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhan Zhang
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yuan Huang
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yuan Yuan Lu
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xinglou Liu
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Sainan Shu
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Feng Fang
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
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Zhang W, Ellingson L, Frascoli F, Heffernan J. An investigation of tuberculosis progression revealing the role of macrophages apoptosis via sensitivity and bifurcation analysis. J Math Biol 2021; 83:31. [PMID: 34436682 PMCID: PMC8387667 DOI: 10.1007/s00285-021-01655-6] [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: 12/18/2020] [Revised: 05/25/2021] [Accepted: 08/16/2021] [Indexed: 02/07/2023]
Abstract
Mycobacterium tuberculosis infection features various disease outcomes: clearance, latency, active disease, and latent tuberculosis infection (LTBI) reactivation. Identifying the decisive factors for disease outcomes and progression is crucial to elucidate the macrophages-tuberculosis interaction and provide insights into therapeutic strategies. To achieve this goal, we first model the disease progression as a dynamical shift among different disease outcomes, which are characterized by various steady states of bacterial concentration. The causal mechanisms of steady-state transitions can be the occurrence of transcritical and saddle-node bifurcations, which are induced by slowly changing parameters. Transcritical bifurcation, occurring when the basic reproduction number equals to one, determines whether the infection clears or spreads. Saddle-node bifurcation is the key mechanism to create and destroy steady states. Based on these two steady-state transition mechanisms, we carry out two sample-based sensitivity analyses on transcritical bifurcation conditions and saddle-node bifurcation conditions. The sensitivity analysis results suggest that the macrophage apoptosis rate is the most significant factor affecting the transition in disease outcomes. This result agrees with the discovery that the programmed cell death (apoptosis) plays a unique role in the complex microorganism-host interplay. Sensitivity analysis narrows down the parameters of interest, but cannot answer how these parameters influence the model outcomes. To do this, we employ bifurcation analysis and numerical simulation to unfold various disease outcomes induced by the variation of macrophage apoptosis rate. Our findings support the hypothesis that the regulation mechanism of macrophage apoptosis affects the host immunity against tuberculosis infection and tuberculosis virulence. Moreover, our mathematical results suggest that new treatments and/or vaccines that regulate macrophage apoptosis in combination with weakening bacillary viability and/or promoting adaptive immunity could have therapeutic value.
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Affiliation(s)
- Wenjing Zhang
- Department of Mathematics and Statistics, Texas Tech University, Broadway and Boston, Lubbock, 79409-1042 TX USA
| | - Leif Ellingson
- Department of Mathematics and Statistics, Texas Tech University, Broadway and Boston, Lubbock, 79409-1042 TX USA
| | - Federico Frascoli
- Department of Mathematics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, 3122, Hawthorne, VIC Australia
| | - Jane Heffernan
- Department of Mathematics and Statistics, Centre for Disease Modelling, York University, 4700 Keele St, Toronto, ON M3J 1P3 Canada
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TNF Signaling Dictates Myeloid and Non-Myeloid Cell Crosstalk to Execute MCMV-Induced Extrinsic Apoptosis. Viruses 2020; 12:v12111221. [PMID: 33126536 PMCID: PMC7693317 DOI: 10.3390/v12111221] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/21/2020] [Accepted: 10/24/2020] [Indexed: 12/13/2022] Open
Abstract
Cytomegaloviruses all encode the viral inhibitor of caspase-8-induced apoptosis (vICA). After binding to this initiator caspase, vICA blocks caspase-8 proteolytic activity and ability to activate caspase-3 and/or caspase-7. In this manner, vICA has long been known to prevent apoptosis triggered via tumor necrosis factor (TNF) family death receptor-dependent extrinsic signaling. Here, we employ fully wild-type murine cytomegalovirus (MCMV) and vICA-deficient MCMV (∆M36) to investigate the contribution of TNF signaling to apoptosis during infection of different cell types. ∆M36 shows the expected ability to kill mouse splenic hematopoietic cells, bone marrow-derived macrophages (BMDM), and dendritic cells (BMDC). Antibody blockade or genetic elimination of TNF protects myeloid cells from death, and caspase-8 activation accompanies cell death. Interferons, necroptosis, and pyroptotic gasdermin D (GSDMD) do not contribute to myeloid cell death. Human and murine fibroblasts or murine endothelial cells (SVEC4-10) normally insensitive to TNF become sensitized to ∆M36-induced apoptosis when treated with TNF or TNF-containing BMDM-conditioned medium. We demonstrate that myeloid cells are the natural source of TNF that triggers apoptosis in either myeloid (autocrine) or non-myeloid cells (paracrine) during ∆M36 infection of mice. Caspase-8 suppression by vICA emerges as key to subverting innate immune elimination of a wide variety of infected cell types.
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Noguchi K, Majima R, Takahashi K, Iwase Y, Yamada S, Satoh K, Koshizuka T, Inoue N. Identification and functional analyses of a cell-death inhibitor encoded by guinea pig cytomegalovirus gp38.1 in cell culture and in animals. J Gen Virol 2020; 101:1270-1279. [PMID: 32915127 DOI: 10.1099/jgv.0.001493] [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: 11/18/2022] Open
Abstract
Cytomegaloviruses (CMVs) employ an array of strategies designed to interfere with host defence responses against pathogens. Studies on such evasion mechanisms are important for understanding the pathogenesis of CMV diseases. Although guinea pig CMV (GPCMV) provides a useful animal model for congenital CMV infection, its evasion strategies are not fully elucidated. Here, we analysed a genome locus that may encode gene products for the GPCMV evasion mechanisms and found the following. (1) RACE analyses identified five transcripts in the GP38-gp38.4 locus, one of which was a spliced product encoding gp38.1. Similarities in the splicing pattern and gene position of gp38.1 to human CMV UL37 and its exon 1 encoding vMIA (viral mitochondria-localized inhibitor of apoptosis) suggest that the gp38.1 gene encodes an apoptosis inhibitor. (2) In a transient transfection assay, gp38.1 localized in the mitochondria and relocated BAX from the cytoplasm to the mitochondria, although its co-localization with BAK was not evident. Further, the expression of gp38.1 partially reduced staurosporine-induced apoptosis. (3) GPCMV defective in the gp38.1 ORF (Δ38.1) and the virus that rescues the defect (r38.1) were generated. Guinea pig fibroblast cells infected with Δ38.1 died earlier than r38.1-infected cells, which resulted in the lower yields of Δ38.1. (4) In animals, viral loads in the spleens of r38.1-infected guinea pigs were higher than those in the spleens of Δ38.1-infected animals. In conclusion, although GPCMV gp38.1 exerts a vMIA-like function, its inhibitory effect was not robust, suggesting the presence of additional inhibitory molecule(s), such as a BAK-specific inhibitor.
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Affiliation(s)
- Kazuma Noguchi
- Present address: Kaken Pharmaceutical, Tokyo, Japan
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Ryuichi Majima
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Keita Takahashi
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Yoshihiko Iwase
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Souichi Yamada
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Keisuke Satoh
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Tetsuo Koshizuka
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Naoki Inoue
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
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Shan L, Li S, Meeldijk J, Blijenberg B, Hendriks A, van Boxtel KJWM, van den Berg SPH, Groves IJ, Potts M, Svrlanska A, Stamminger T, Wills MR, Bovenschen N. Killer cell proteases can target viral immediate-early proteins to control human cytomegalovirus infection in a noncytotoxic manner. PLoS Pathog 2020; 16:e1008426. [PMID: 32282833 PMCID: PMC7179929 DOI: 10.1371/journal.ppat.1008426] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 04/23/2020] [Accepted: 02/21/2020] [Indexed: 12/17/2022] Open
Abstract
Human cytomegalovirus (HCMV) is the most frequent viral cause of congenital defects and can trigger devastating disease in immune-suppressed patients. Cytotoxic lymphocytes (CD8+ T cells and NK cells) control HCMV infection by releasing interferon-γ and five granzymes (GrA, GrB, GrH, GrK, GrM), which are believed to kill infected host cells through cleavage of intracellular death substrates. However, it has recently been demonstrated that the in vivo killing capacity of cytotoxic T cells is limited and multiple T cell hits are required to kill a single virus-infected cell. This raises the question whether cytotoxic lymphocytes can use granzymes to control HCMV infection in a noncytotoxic manner. Here, we demonstrate that (primary) cytotoxic lymphocytes can block HCMV dissemination independent of host cell death, and interferon-α/β/γ. Prior to killing, cytotoxic lymphocytes induce the degradation of viral immediate-early (IE) proteins IE1 and IE2 in HCMV-infected cells. Intriguingly, both IE1 and/or IE2 are directly proteolyzed by all human granzymes, with GrB and GrM being most efficient. GrB and GrM cleave IE1 after Asp398 and Leu414, respectively, likely resulting in IE1 aberrant cellular localization, IE1 instability, and functional impairment of IE1 to interfere with the JAK-STAT signaling pathway. Furthermore, GrB and GrM cleave IE2 after Asp184 and Leu173, respectively, resulting in IE2 aberrant cellular localization and functional abolishment of IE2 to transactivate the HCMV UL112 early promoter. Taken together, our data indicate that cytotoxic lymphocytes can also employ noncytotoxic ways to control HCMV infection, which may be explained by granzyme-mediated targeting of indispensable viral proteins during lytic infection. Human cytomegalovirus (HCMV) is the leading viral cause of congenital defects, can trigger disease in immune-compromised patients, and plays roles in cancer development. Cytotoxic lymphocytes kill HCMV-infected cells via releasing a set of five cytotoxic serine proteases called granzymes. However, the killing capacity of cytotoxic cells is limited and multiple T cell hits are required to kill a single virus-infected cell. This raises the question whether cytotoxic lymphocytes can use granzymes to control HCMV infection in a noncytotoxic manner. Here, we show that cytotoxic lymphocytes can also use granzymes to inhibit HCMV replication in absence of cell death. All five granzymes cleave and inactivate both viral immediate-early (IE1/2) proteins, which are essential players for initiating HCMV infection. Our data support the model that cytotoxic cells employ granzymes to dampen HCMV replication prior to accumulation of sufficient hits to kill the infected cell.
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Affiliation(s)
- Liling Shan
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Shuang Li
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jan Meeldijk
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bernadet Blijenberg
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Astrid Hendriks
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | - Ian J. Groves
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Martin Potts
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Adriana Svrlanska
- Institute of Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany
| | | | - Mark R. Wills
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Niels Bovenschen
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
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Xi Y, Harwood S, Wise LM, Purdy JG. Human Cytomegalovirus pUL37x1 Is Important for Remodeling of Host Lipid Metabolism. J Virol 2019; 93:e00843-19. [PMID: 31391267 PMCID: PMC6803270 DOI: 10.1128/jvi.00843-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/19/2019] [Indexed: 12/11/2022] Open
Abstract
Human cytomegalovirus (HCMV) replication requires host metabolism. Infection alters the activity in multiple metabolic pathways, including increasing fatty acid elongation and lipid synthesis. The virus-host interactions regulating the metabolic changes associated with replication are essential for infection. While multiple host factors, including kinases and transcription factors, important for metabolic changes that occur following HCMV infection have been identified, little is known about the viral factors required to alter metabolism. In this study, we tested the hypothesis that pUL37x1 is important for the metabolic remodeling that is necessary for HCMV replication using a combination of metabolomics, lipidomics, and metabolic tracers to measure fatty acid elongation. We observed that fibroblast cells infected with wild-type (WT) HCMV had levels of metabolites similar to those in cells infected with a mutant virus lacking the UL37x1 gene, subUL37x1. However, we found that relative to WT-infected cells, subUL37x1-infected cells had reduced levels of two host proteins that were previously demonstrated to be important for lipid metabolism during HCMV infection: fatty acid elongase 7 (ELOVL7) and the endoplasmic reticulum (ER) stress-related kinase PERK. Moreover, we observed that HCMV infection results in an increase in phospholipids with very-long-chain fatty acid tails (PL-VLCFAs) that contain 26 or more carbons in one of their two tails. The levels of many PL-VLCFAs were lower in subUL37x1-infected cells than in WT-infected cells. Overall, we conclude that although pUL37x1 is not necessary for network-wide metabolic changes associated with HCMV infection, it is important for the remodeling of a subset of metabolic changes that occur during infection.IMPORTANCE Human cytomegalovirus (HCMV) is a common pathogen that asymptomatically infects most people and establishes a lifelong infection. However, HCMV can cause end-organ disease that results in death in the immunosuppressed and is a leading cause of birth defects. HCMV infection depends on host metabolism, including lipid metabolism. However, the viral mechanisms for remodeling of metabolism are poorly understood. In this study, we demonstrate that the viral UL37x1 protein (pUL37x1) is important for infection-associated increases in lipid metabolism, including fatty acid elongation to produce very-long-chain fatty acids (VLCFAs). Furthermore, we found that HCMV infection results in a significant increase in phospholipids, particularly those with VLCFA tails (PL-VLCFAs). We found that pUL37x1 was important for the high levels of fatty acid elongation and PL-VLCFA accumulation that occur in HCMV-infected cells. Our findings identify a viral protein that is important for changes in lipid metabolism that occur following HCMV infection.
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Affiliation(s)
- Yuecheng Xi
- Department of Immunobiology, University of Arizona, Tucson, Arizona, USA
| | - Samuel Harwood
- Department of Immunobiology, University of Arizona, Tucson, Arizona, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Lisa M Wise
- Department of Immunobiology, University of Arizona, Tucson, Arizona, USA
| | - John G Purdy
- Department of Immunobiology, University of Arizona, Tucson, Arizona, USA
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
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Wajant H, Siegmund D. TNFR1 and TNFR2 in the Control of the Life and Death Balance of Macrophages. Front Cell Dev Biol 2019; 7:91. [PMID: 31192209 PMCID: PMC6548990 DOI: 10.3389/fcell.2019.00091] [Citation(s) in RCA: 213] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/14/2019] [Indexed: 12/18/2022] Open
Abstract
Macrophages stand in the first line of defense against a variety of pathogens but are also involved in the maintenance of tissue homeostasis. To fulfill their functions macrophages sense a broad range of pathogen- and damage-associated molecular patterns (PAMPs/DAMPs) by plasma membrane and intracellular pattern recognition receptors (PRRs). Intriguingly, the overwhelming majority of PPRs trigger the production of the pleiotropic cytokine tumor necrosis factor-alpha (TNF). TNF affects almost any type of cell including macrophages themselves. TNF promotes the inflammatory activity of macrophages but also controls macrophage survival and death. TNF exerts its activities by stimulation of two different types of receptors, TNF receptor-1 (TNFR1) and TNFR2, which are both expressed by macrophages. The two TNF receptor types trigger distinct and common signaling pathways that can work in an interconnected manner. Based on a brief general description of major TNF receptor-associated signaling pathways, we focus in this review on research of recent years that revealed insights into the molecular mechanisms how the TNFR1-TNFR2 signaling network controls the life and death balance of macrophages. In particular, we discuss how the TNFR1-TNFR2 signaling network is integrated into PRR signaling.
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Affiliation(s)
- Harald Wajant
- Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Würzburg, Würzburg, Germany
| | - Daniela Siegmund
- Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Würzburg, Würzburg, Germany
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Marín D, Marín N, del Corral H, López L, Ramirez-Agudelo ME, Rojas CA, Arbeláez MP, García LF, Rojas M. PPD-induced monocyte mitochondrial damage is associated with a protective effect to develop tuberculosis in BCG vaccinated individuals: A cohort study. PLoS One 2017; 12:e0171930. [PMID: 28222109 PMCID: PMC5319776 DOI: 10.1371/journal.pone.0171930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 01/29/2017] [Indexed: 12/04/2022] Open
Abstract
Introduction The mechanisms of mononuclear phagocyte death have been associated with the permissiveness and resistance to mycobacterial replication, but it remains unknown whether or not they help predict the risk of developing TB. Objective To describe the factors associated with the induction of monocyte mitochondrial and membrane damage in response to PPD as well as determine if this type of damage might predict the susceptibility of developing active tuberculosis in a cohort of household contacts (HHCs) from Medellin, Colombia from 2005 to 2008. Methods The prospective cohort study contains 2060 HHCs patients with pulmonary tuberculosis who were meticulously followed for two years. A survey of the socio-demographic, clinical, epidemiological factors and blood samples were collected. Mononuclear cell cultures were stimulated with or without PPD and the type of monocyte death was determined by the flow of cytometry, an indicator was also used for its analysis. Logistic regression was adjusted by the Generalized Estimations Equations and the survival was estimated with the Kaplan-Meier and Cox regression. Confidence intervals were used for estimating the association. Results 1,859 out of 2,060 blood samples of the HHCs patients analyzed showed monocyte death. In response to PPD, 83.4% underwent mitochondrial damage while 50.9% had membrane damage. The membrane damage in response to PPD was higher in children under 4 years (OR: 1.57; (95% CI: 1.1 to 2.4) and the HHCs who slept regularly in the same household has an index case of (OR: 1.54; 95% CI: 1.0 to 2.3). After adjustment by age, comorbidities, nutritional status, proximity to index case and overcrowding, the risk of developing active TB among BCG vaccinated HHCs individuals with induction of mitochondrial damage was HR = 0.19 (95% CI: 0.1 to 0.5). Conclusions The induction of monocytes mitochondrial damage by PPD stimulation correlates with protection of TB disease development in BCG-vaccinated HHCs. This represents a potential tool to predict susceptibility of developing active disease in this population.
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Affiliation(s)
- Diana Marín
- Grupo de Epidemiología, Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
- * E-mail: (DM); (MR)
| | - Nancy Marín
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
- Grupo de Inmunología Celular e Inmunogenética, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Helena del Corral
- Grupo de Epidemiología, Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
| | - Lucelly López
- Grupo de Epidemiología, Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
| | - María Elena Ramirez-Agudelo
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
- Grupo de Inmunología Celular e Inmunogenética, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Carlos A. Rojas
- Grupo de Epidemiología, Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
| | - María P. Arbeláez
- Grupo de Epidemiología, Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
| | - Luis F. García
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
- Grupo de Inmunología Celular e Inmunogenética, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Mauricio Rojas
- Centro Colombiano de Investigación en Tuberculosis (CCITB), Colciencias, Medellín, Colombia
- Grupo de Inmunología Celular e Inmunogenética, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
- Unidad de Citometría de Flujo, Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia
- * E-mail: (DM); (MR)
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The cytomegalovirus protein UL138 induces apoptosis of gastric cancer cells by binding to heat shock protein 70. Oncotarget 2016; 7:5630-45. [PMID: 26735338 PMCID: PMC4868710 DOI: 10.18632/oncotarget.6800] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 12/05/2015] [Indexed: 01/16/2023] Open
Abstract
It has been hypothesized that human cytomegalovirus (HCMV) could act as a tumor promoter and play an “oncomodulatory” role in the neoplastic process of several human malignancies. However, we demonstrate for the first time that UL138, a HCMV latency-associated gene, could act as a tumor inhibitor in gastric cancer (GC). The expression of UL138 is down-regulated in HCMV positive gastric adenocarcinoma tissues, especially in poorly or none differentiated tumors. Overexpression of UL138 in several human GC cell lines inhibits cell viability and induces apoptosis, in association with the reduction of an anti-apoptotic Bcl-2 protein and the induction of cleaved caspase-3 and caspase-9. Moreover, protein array analysis reveals that UL138 interacts with a chaperone protein, heat shock protein 70 (HSP70). This interaction is confirmed by immunoprecipitation and immunostaining in situ in GC cell lines. In addition, this UL138-mediated cancer cell death could efficiently lead to suppression of human tumor growth in a xenograft animal model of GC. In conclusion, these results uncover a previously unknown role of the cytomegalovirus protein UL138 in inducing GC cells apoptosis, which might imply a general mechanism that viral proteins inhibit cancer growth in interactions with both chaperones and apoptosis-related proteins. Our findings might provide a potential target for new therapeutic strategies of GC treatment.
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Omoto S, Guo H, Talekar GR, Roback L, Kaiser WJ, Mocarski ES. Suppression of RIP3-dependent necroptosis by human cytomegalovirus. J Biol Chem 2015; 290:11635-48. [PMID: 25778401 DOI: 10.1074/jbc.m115.646042] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Indexed: 12/23/2022] Open
Abstract
Necroptosis is an alternate programmed cell death pathway that is unleashed by caspase-8 compromise and mediated by receptor-interacting protein kinase 3 (RIP3). Murine cytomegalovirus (CMV) and herpes simplex virus (HSV) encode caspase-8 inhibitors that prevent apoptosis together with competitors of RIP homotypic interaction motif (RHIM)-dependent signal transduction to interrupt the necroptosis. Here, we show that pro-necrotic murine CMV M45 mutant virus drives virus-induced necroptosis during nonproductive infection of RIP3-expressing human fibroblasts, whereas WT virus does not. Thus, M45-encoded RHIM competitor, viral inhibitor of RIP activation, sustains viability of human cells like it is known to function in infected mouse cells. Importantly, human CMV is shown to block necroptosis induced by either TNF or M45 mutant murine CMV in RIP3-expressing human cells. Human CMV blocks TNF-induced necroptosis after RIP3 activation and phosphorylation of the mixed lineage kinase domain-like (MLKL) pseudokinase. An early, IE1-regulated viral gene product acts on a necroptosis step that follows MLKL phosphorylation prior to membrane leakage. This suppression strategy is distinct from RHIM signaling competition by murine CMV or HSV and interrupts an execution process that has not yet been fully elaborated.
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Affiliation(s)
- Shinya Omoto
- From the Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Hongyan Guo
- From the Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Ganesh R Talekar
- From the Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Linda Roback
- From the Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322
| | - William J Kaiser
- From the Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Edward S Mocarski
- From the Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322
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13
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Alibek K, Irving S, Sautbayeva Z, Kakpenova A, Bekmurzayeva A, Baiken Y, Imangali N, Shaimerdenova M, Mektepbayeva D, Balabiyev A, Chinybayeva A. Disruption of Bcl-2 and Bcl-xL by viral proteins as a possible cause of cancer. Infect Agent Cancer 2014; 9:44. [PMID: 25699089 PMCID: PMC4333878 DOI: 10.1186/1750-9378-9-44] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 11/25/2014] [Indexed: 01/01/2023] Open
Abstract
The Bcl proteins play a critical role in apoptosis, as mutations in family members interfere with normal programmed cell death. Such events can cause cell transformation, potentially leading to cancer. Recent discoveries indicate that some viral proteins interfere with Bcl proteins either directly or indirectly; however, these data have not been systematically described. Some viruses encode proteins that reprogramme host cellular signalling pathways controlling cell differentiation, proliferation, genomic integrity, cell death, and immune system recognition. This review analyses and summarises the existing data and discusses how viral proteins interfere with normal pro- and anti-apoptotic functions of Bcl-2 and Bcl-xL. Particularly, this article focuses on how viral proteins, such as Herpesviruses, HTLV-1, HPV and HCV, block apoptosis and how accumulation of such interference predisposes cancer development. Finally, we discuss possible ways to prevent and treat cancers using a combination of traditional therapies and antiviral preparations that are effective against these viruses.
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Affiliation(s)
- Kenneth Alibek
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan ; National Medical Holding, 2 Syganak Street, Astana, 010000 Kazakhstan
| | - Stephanie Irving
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Zarina Sautbayeva
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Ainur Kakpenova
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Aliya Bekmurzayeva
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Yeldar Baiken
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Nurgul Imangali
- School of Science and Technology, Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Madina Shaimerdenova
- School of Science and Technology, Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Damel Mektepbayeva
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Arnat Balabiyev
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
| | - Aizada Chinybayeva
- Nazarbayev University Research and Innovation System (NURIS), Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana, 010000 Kazakhstan
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14
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The carboxy terminal region of the human cytomegalovirus immediate early 1 (IE1) protein disrupts type II inteferon signaling. Viruses 2014; 6:1502-24. [PMID: 24699362 PMCID: PMC4014707 DOI: 10.3390/v6041502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/07/2014] [Accepted: 03/07/2014] [Indexed: 12/21/2022] Open
Abstract
Interferons (IFNs) activate the first lines of defense against viruses, and promote innate and adaptive immune responses to viruses. We report that the immediate early 1 (IE1) protein of human cytomegalovirus (HCMV) disrupts signaling by IFNγ. The carboxyl-terminal region of IE1 is required for this function. We found no defect in the initial events in IFNγ signaling or in nuclear accumulation of signal transducer and activator of transcription 1 (STAT1) in IE1-expressing cells. Moreover, we did not observe an association between disruption of IFNγ signaling and nuclear domain 10 (ND10) disruption. However, there is reduced binding of STAT1 homodimers to target gamma activated sequence (GAS) elements in the presence of IE1. Co-immunoprecipitation studies failed to support a direct interaction between IE1 and STAT1, although these studies revealed that the C-terminal region of IE1 was required for interaction with STAT2. Together, these results indicate that IE1 disrupts IFNγ signaling by interfering with signaling events in the nucleus through a novel mechanism.
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15
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Human cytomegalovirus pUL37x1-induced calcium flux activates PKCα, inducing altered cell shape and accumulation of cytoplasmic vesicles. Proc Natl Acad Sci U S A 2014; 111:E1140-8. [PMID: 24616524 DOI: 10.1073/pnas.1402515111] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The human cytomegalovirus immediate-early protein pUL37x1 induces the release of Ca(2+) stores from the endoplasmic reticulum into the cytosol. This release causes reorganization of the cellular actin cytoskeleton with concomitant cell rounding. Here we demonstrate that pUL37x1 activates Ca(2+)-dependent protein kinase Cα (PKCα). Both PKCα and Rho-associated protein kinases are required for actin reorganization and cell rounding; however, only PKCα is required for the efficient production of virus progeny, arguing that HCMV depends on the kinase for a second function. PKCα activation is also needed for the production of large (1-5 μm) cytoplasmic vesicles late after infection. The production of these vesicles is blocked by inhibition of fatty acid or phosphatidylinositol-3-phosphate biosynthesis, and the failure to produce vesicles is correlated with substantially reduced production of enveloped virus capsids. These results connect earlier work identifying a requirement for lipid synthesis with specific morphological changes, and support the argument that the PKCα-induced large vesicles are either required for the efficient production of mature virus particles or serve as a marker for the process.
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16
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Valle Oseguera CA, Spencer JV. cmvIL-10 stimulates the invasive potential of MDA-MB-231 breast cancer cells. PLoS One 2014; 9:e88708. [PMID: 24520416 PMCID: PMC3919807 DOI: 10.1371/journal.pone.0088708] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/10/2014] [Indexed: 01/05/2023] Open
Abstract
Cancer is the result of unregulated cell growth that leads to tumor formation, and in many cases, metastases. Although there are several risk factors associated with cancer, one area that remains poorly understood is the impact of infectious disease. Human cytomegalovirus (HCMV) is a member of the herpesvirus family that is highly prevalent in the population. HCMV usually causes clinical disease only in immune compromised individuals, but recent evidence suggests that HCMV may be strongly associated with some forms of cancer, particularly glioblastoma and breast cancer. We investigated the possibility that cmvIL-10, a viral cytokine with homology to human IL-10 that is secreted from infected cells, could act in a paracrine manner to alter the tumor microenvironment, induce cell signaling, and increase the invasive potential of cancer cells. We found that human MDA-MB-231 breast cancer cells express the IL-10 receptor and that exposure to cmvIL-10 results in activation of Stat3, a transcription factor strongly associated with enhanced metastatic potential and chemo-resistance. In addition, cmvIL-10 stimulated an increase in DNA synthesis and cell proliferation, protected MDA-MB-231 cells from etoposide-induced apoptosis, and also greatly enhanced chemotaxis toward epidermal growth factor (EGF). These results suggest a significant and wide-ranging role for cmvIL-10 in the progression of breast cancer and could have broad implications for the diagnosis and treatment of cancer in HCMV-positive patients.
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Affiliation(s)
- Cendy A. Valle Oseguera
- Department of Biology, University of San Francisco, San Francisco, California, United States of America
| | - Juliet V. Spencer
- Department of Biology, University of San Francisco, San Francisco, California, United States of America
- * E-mail:
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17
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Sinclair JH, Reeves MB. Human cytomegalovirus manipulation of latently infected cells. Viruses 2013; 5:2803-24. [PMID: 24284875 PMCID: PMC3856416 DOI: 10.3390/v5112803] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/11/2013] [Accepted: 11/13/2013] [Indexed: 12/28/2022] Open
Abstract
Primary infection with human cytomegalovirus (HCMV) results in the establishment of a lifelong infection of the host which is aided by the ability of HCMV to undergo a latent infection. One site of HCMV latency in vivo is in haematopoietic progenitor cells, resident in the bone marrow, with genome carriage and reactivation being restricted to the cells of the myeloid lineage. Until recently, HCMV latency has been considered to be relatively quiescent with the virus being maintained essentially as a “silent partner” until conditions are met that trigger reactivation. However, advances in techniques to study global changes in gene expression have begun to show that HCMV latency is a highly active process which involves expression of specific latency-associated viral gene products which orchestrate major changes in the latently infected cell. These changes are argued to help maintain latent infection and to modulate the cellular environment to the benefit of latent virus. In this review, we will discuss these new findings and how they impact not only on our understanding of the biology of HCMV latency but also how they could provide tantalising glimpses into mechanisms that could become targets for the clearance of latent HCMV.
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Affiliation(s)
- John H. Sinclair
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Hills Road, Cambridge, CB2 0QQ, UK; E-Mail:
| | - Matthew B. Reeves
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College London, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44-(0)207-794-0500 (ext. 33109)
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18
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Kaiser WJ, Upton JW, Mocarski ES. Viral modulation of programmed necrosis. Curr Opin Virol 2013; 3:296-306. [PMID: 23773332 DOI: 10.1016/j.coviro.2013.05.019] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 05/21/2013] [Accepted: 05/22/2013] [Indexed: 01/16/2023]
Abstract
Apoptosis and programmed necrosis balance each other as alternate first line host defense pathways against which viruses have evolved countermeasures. Intrinsic apoptosis, the critical programmed cell death pathway that removes excess cells during embryonic development and tissue homeostasis, follows a caspase cascade triggered at mitochondria and modulated by virus-encoded anti-apoptotic B cell leukemia (BCL)2-like suppressors. Extrinsic apoptosis controlled by caspase 8 arose during evolution to trigger executioner caspases directly, circumventing viral suppressors of intrinsic (mitochondrial) apoptosis and providing the selective pressure for viruses to acquire caspase 8 suppressors. Programmed necrosis likely evolved most recently as a 'trap door' adaptation to extrinsic apoptosis. Receptor interacting protein (RIP)3 kinase (also called RIPK3) becomes active when either caspase 8 activity or polyubiquitylation of RIP1 is compromised. This evolutionary dialog implicates caspase 8 as a 'supersensor' alternatively activating and suppressing cell death pathways.
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Affiliation(s)
- William J Kaiser
- Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322, USA
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19
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Arnolds KL, Lares AP, Spencer JV. The US27 gene product of human cytomegalovirus enhances signaling of host chemokine receptor CXCR4. Virology 2013; 439:122-31. [PMID: 23490053 DOI: 10.1016/j.virol.2013.02.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 12/12/2012] [Accepted: 02/12/2013] [Indexed: 01/09/2023]
Abstract
Human cytomegalovirus (HCMV) is a member of the Herpesviridae family that manipulates host immune responses and establishes life-long latent infection, in part through mimicry of cytokines, chemokines, and chemokine receptors. The HCMV US27 gene product is a putative chemokine receptor with no known ligands. We generated a stable US27 cell line to screen for chemokine ligands but unexpectedly found that US27 potentiated the activity of an endogenous human chemokine receptor, CXCR4. Cells expressing both US27 and CXCR4 exhibited greater calcium mobilization and enhanced chemotaxis in response to CXCL12/SDF-1α than controls. Quantitative RT-PCR revealed a significant increase in CXCR4 expression when US27 was present, and elevated CXCR4 receptor levels were detected via flow cytometry, western blot, and immunofluorescence microscopy. Potentiation of CXCR4 signaling by US27 could represent a novel strategy by which HCMV targets virus-infected cells to the bone marrow in order to expand the reservoir of latently infected cells.
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Affiliation(s)
- Kathleen L Arnolds
- Department of Biology, University of San Francisco, San Francisco, California 94117, USA
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20
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McCormick AL, Roback L, Wynn G, Mocarski ES. Multiplicity-dependent activation of a serine protease-dependent cytomegalovirus-associated programmed cell death pathway. Virology 2012; 435:250-7. [PMID: 23159167 DOI: 10.1016/j.virol.2012.08.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 01/11/2012] [Accepted: 08/26/2012] [Indexed: 01/25/2023]
Abstract
At a low MOI (≤0.01), cytomegalovirus-associated programmed cell death terminates productive infection via a pathway triggered by the mitochondrial serine protease HtrA2/Omi. This infected cell death is associated with late phase replication events naturally suppressed by the viral mitochondrial inhibitor of apoptosis (vMIA). Here, higher MOI (ranging from 0.1-3.0) triggers cell death earlier during infection independent of viral DNA synthesis. Thus, MOI-dependent activating signals early, at high MOI, or late, at low MOI, during replication promote serine protease-dependent death that is suppressed by vMIA. Treatment with an antioxidant targeting reactive oxygen species (ROS) or the serine protease inhibitor N-alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK) delays cell death, and the combination has an additive impact. These studies identify serine proteases and ROS as important factors triggering programmed cell death induced by vMIA-deficient virus, and show that this death pathway occurs earlier and reduces viral yields as the MOI is increased.
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Affiliation(s)
- A Louise McCormick
- Department of Microbiology and Immunology and Emory Vaccine Center, Emory University School of Medicine, 1462 Clifton Rd NE, Atlanta, GA 30322, USA.
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21
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Al-Ali A, Timoshenko O, Martin BA, Sweet C. Role of mutations identified in ORFs M27, M36, m139, m141, and m143 in the temperature-sensitive phenotype of murine cytomegalovirus mutanttsm5. J Med Virol 2012; 84:912-22. [DOI: 10.1002/jmv.23273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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22
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Human cytomegalovirus activation of ERK and myeloid cell leukemia-1 protein correlates with survival of latently infected cells. Proc Natl Acad Sci U S A 2011; 109:588-93. [PMID: 22203987 DOI: 10.1073/pnas.1114966108] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The ability of human CMV (HCMV) to enter and establish a latent infection in myeloid cells is crucial for survival and transmission in the human population. Initial pathogen binding and entry triggers a number of antiviral responses, including the activation of proapoptotic cell death pathways, which must be countered during latency establishment. However, mechanisms responsible for a prosurvival state in myeloid cells upon latent HCMV infection remain completely undefined. We hypothesized that the cellular antiapoptotic machinery must be initially activated by HCMV to promote early survival events upon entry. Here we show that HCMV transiently protects nonpermissive myeloid cells from chemical and virus entry induced cell death by up-regulating a key myeloid cell survival gene, myeloid cell leukemia (MCL)-1 protein. The induction of MCL-1 expression was independent of viral gene expression but dependent on activation of the ERK-MAPK pathway by viral glycoprotein B. Inhibition of ERK-MAPK signaling, inhibition of HCMV fusion, antibody-mediated neutralization of glycoprotein B signaling or expression of a shRNA against MCL-1 all correlated with increased cell death in response to virus infection or chemical stimulation. Finally we show that activation of ERK-MAPK signaling impacts on long-term latency and reactivation in hematopoietic cells. Thus, HCMV primes myeloid cells for from the initial virus-cell encounter. Given the importance of ERK and MCL-1 for myeloid cell survival, the successful establishment of HCMV latency in myeloid progenitors begins at the point of virus entry.
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Mocarski ES, Upton JW, Kaiser WJ. Viral infection and the evolution of caspase 8-regulated apoptotic and necrotic death pathways. Nat Rev Immunol 2011; 12:79-88. [PMID: 22193709 PMCID: PMC4515451 DOI: 10.1038/nri3131] [Citation(s) in RCA: 327] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pathogens specifically target both the caspase 8-dependent apoptotic cell death pathway and the necrotic cell death pathway that is dependent on receptor-interacting protein 1 (RIP1; also known as RIPK1) and RIP3 (also known as RIPK3). The fundamental co-regulation of these two cell death pathways emerged when the midgestational death of mice deficient in FAS-associated death domain protein (FADD) or caspase 8 was reversed by elimination of RIP1 or RIP3, indicating a far more entwined relationship than previously appreciated. Thus, mammals require caspase 8 activity during embryogenesis to suppress the kinases RIP1 and RIP3 as part of the dialogue between two distinct cell death processes that together fulfil reinforcing roles in the host defence against intracellular pathogens such as herpesviruses.
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Affiliation(s)
- Edward S Mocarski
- Department of Microbiology and Immunology, Emory Vaccine Center, 1462 Clifton Rd. NE, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Jason W Upton
- Section of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin 78712, USA
| | - William J Kaiser
- Department of Microbiology and Immunology, Emory Vaccine Center, 1462 Clifton Rd. NE, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Abstract
Cytomegalovirus (CMV) infection is the most common opportunistic infection in immunosuppressed individuals, such as transplant recipients or people living with HIV/AIDS, and congenital CMV is the leading viral cause of developmental disabilities in infants. Due to the highly species-specific nature of CMV, animal models that closely recapitulate human CMV (HCMV) are of growing importance for vaccine development. Here we present the genomic sequence of a novel nonhuman primate CMV from cynomolgus macaques (Macaca fascicularis; CyCMV). CyCMV (Ottawa strain) was isolated from the urine of a healthy, captive-bred, 4-year-old cynomolgus macaque of Philippine origin, and the viral genome was sequenced using next-generation Illumina sequencing to an average of 516-fold coverage. The CyCMV genome is 218,041 bp in length, with 49.5% G+C content and 84% protein-coding density. We have identified 262 putative open reading frames (ORFs) with an average coding length of 789 bp. The genomic organization of CyCMV is largely colinear with that of rhesus macaque CMV (RhCMV). Of the 262 CyCMV ORFs, 137 are homologous to HCMV genes, 243 are homologous to RhCMV 68.1, and 200 are homologous to RhCMV 180.92. CyCMV encodes four ORFs that are not present in RhCMV strain 68.1 or 180.92 but have homologies with HCMV (UL30, UL74A, UL126, and UL146). Similar to HCMV, CyCMV does not produce the RhCMV-specific viral homologue of cyclooxygenase-2. This newly characterized CMV may provide a novel model in which to study CMV biology and HCMV vaccine development.
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Weinlich R, Dillon CP, Green DR. Ripped to death. Trends Cell Biol 2011; 21:630-7. [PMID: 21978761 DOI: 10.1016/j.tcb.2011.09.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 09/04/2011] [Accepted: 09/06/2011] [Indexed: 11/16/2022]
Abstract
An old puzzle in the field of cell death was solved recently: the mysterious embryonic lethality of animals deficient in caspase-8 or Fas-associated death domain (FADD), proteins involved in a pathway of apoptosis. This lethality is caused by a failure to develop the yolk sac vasculature rather than a lack of apoptosis. Remarkably, development is rescued by ablation of either of two receptor interacting serine-threonine kinases (RIPKs). Despite being well known cell killers, caspase-8 and FADD act together to block RIPK-mediated necrosis. To manifest this newly elucidated pro-survival function, FADD and caspase-8 depend on FLIP(Long), a catalytically inactive caspase-8 homolog. In this review, the mechanism by which RIPK necrotic death is inhibited by this trio is discussed, as well as how RIPKs might themselves mediate cell death.
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Affiliation(s)
- Ricardo Weinlich
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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26
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Abstract
Human cytomegalovirus (CMV), one of the eight herpesviruses that commonly infect humans, is best known for its propensity to cause disease in immunocompromised patients, especially transplant recipients, patients with advanced AIDS, and congenitally infected newborns. Advances in molecular virology coupled with improvements in diagnostic methods and treatment options have vastly improved our understanding of and ability to manage CMV, but many uncertainties remain, including the mechanisms of persistence and pathogenesis and its hypothesized roles in a variety of human illnesses. Here we review recent advances that are reshaping our view and approach to this fascinating virus.
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Affiliation(s)
- Michael Boeckh
- Division of Vaccine and Infectious Disease and
Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
Department of Medicine, University of Washington, Seattle, Washington, USA.
Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Adam P. Geballe
- Division of Vaccine and Infectious Disease and
Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
Department of Medicine, University of Washington, Seattle, Washington, USA.
Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
Department of Microbiology, University of Washington, Seattle, Washington, USA
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Upton JW, Kaiser WJ, Mocarski ES. Virus inhibition of RIP3-dependent necrosis. Cell Host Microbe 2010; 7:302-313. [PMID: 20413098 DOI: 10.1016/j.chom.2010.03.006] [Citation(s) in RCA: 449] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 01/27/2010] [Accepted: 03/12/2010] [Indexed: 12/15/2022]
Abstract
Viral infection activates cytokine expression and triggers cell death, the modulation of which is important for successful pathogenesis. Necroptosis is a form of programmed necrosis dependent on two related RIP homotypic interaction motif (RHIM)-containing signaling adaptors, receptor-interacting protein kinases (RIP) 1 and 3. We find that murine cytomegalovirus infection induces RIP3-dependent necrosis. Whereas RIP3 kinase activity and RHIM-dependent interactions control virus-associated necrosis, virus-induced death proceeds independently of RIP1 and is therefore distinct from TNFalpha-dependent necroptosis. Viral M45-encoded inhibitor of RIP activation (vIRA) targets RIP3 during infection and disrupts RIP3-RIP1 interactions characteristic of TNFalpha-induced necroptosis, thereby suppressing both death pathways. Importantly, attenuation of vIRA mutant virus in wild-type mice is normalized in RIP3-deficient mice. Thus, vIRA function validates necrosis as central to host defense against viral infections and highlights the benefit of multiple virus-encoded cell-death suppressors that inhibit not only apoptotic, but also necrotic mechanisms of virus clearance.
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Affiliation(s)
- Jason W Upton
- Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - William J Kaiser
- Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Edward S Mocarski
- Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322, USA
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Loewendorf A, Benedict CA. Modulation of host innate and adaptive immune defenses by cytomegalovirus: timing is everything. J Intern Med 2010; 267:483-501. [PMID: 20433576 PMCID: PMC2902254 DOI: 10.1111/j.1365-2796.2010.02220.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Human cytomegalovirus (HCMV) (HHV-5, a beta-herpesvirus) causes the vast majority of infection-related congenital birth defects, and can trigger severe disease in immune suppressed individuals. The high prevalence of societal infection, the establishment of lifelong persistence and the growing number of immune-related diseases where HCMV is touted as a potential promoter is slowly heightening public awareness to this virus. The millions of years of co-evolution between CMV and the immune system of its host provides for a unique opportunity to study immune defense strategies, and pathogen counterstrategies. Dissecting the timing of the cellular and molecular processes that regulate innate and adaptive immunity to this persistent virus has revealed a complex defense network that is shaped by CMV immune modulation, resulting in a finely tuned host-pathogen relationship.
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Affiliation(s)
- A Loewendorf
- Division of Molecular Immunology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
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29
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Dou J, Li X, Cai Y, Chen H, Zhu S, Wang Q, Zou X, Mei Y, Yang Q, Li W, Han Y. Human cytomegalovirus induces caspase-dependent apoptosis of megakaryocytic CHRF-288-11 cells by activating the JNK pathway. Int J Hematol 2010; 91:620-9. [PMID: 20376580 DOI: 10.1007/s12185-010-0560-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/14/2010] [Accepted: 03/16/2010] [Indexed: 11/30/2022]
Abstract
Human cytomegalovirus (HCMV) infection is usually implicated in thrombocytopenia occurring in newborns and immunocompromised patients. However, the underlying mechanisms remain elusive. This study was conducted to investigate the effects of HCMV infection on the viability of megakaryocytic CHRF-288-11 cells and the underlying mechanisms involved. RT-PCR for determining mRNA expression of HCMV immediate early gene 1 and Western blot for measuring protein expression of late HCMV gene pp65 showed that CHRF-288-11 cells were susceptible to HCMV infection. HCMV infection reduced the viability of CHRF-288-11 cells via apoptosis in a dose- and time-dependent manner. Both caspase 3 and c-Jun terminal kinase (JNK) signaling pathway were activated in the HCMV-treated CHRF-288-11 cells. z-DEVD-fmk (a caspase inhibitor) and SP600125 (a JNK inhibitor) significantly prevented the death of CHRF-288-11 cells induced by HCMV, respectively. Furthermore, inhibition of JNK activity could reduce the formation of active caspase 3 induced by HCMV. Interestingly, the co-application of antivirus drug ganciclovir and SP600125 synergistically prevented the death of CHRF-288-11 cells induced by HCMV. Collectively, these findings suggest that HCMV infection may induce the caspase-dependent apoptosis of megakaryocytic CHRF-288-11 cells by the activation of JNK signaling pathway.
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Affiliation(s)
- Juan Dou
- Department of Pediatrics, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
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The human cytomegalovirus UL36 gene controls caspase-dependent and -independent cell death programs activated by infection of monocytes differentiating to macrophages. J Virol 2010; 84:5108-23. [PMID: 20219915 DOI: 10.1128/jvi.01345-09] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The cellular protease caspase-8 activates extrinsic apoptosis and also functions to promote monocyte-to-macrophage differentiation. Differentiation-induced alterations to antiviral caspase-8-dependent cell death pathways are unclear. Here, we show THP-1 monocyte-to-macrophage differentiation alters the specific cell death pathways activated in response to human cytomegalovirus (HCMV) infection. Employing viruses with mutations in UL36, the gene that encodes the viral inhibitor of caspase-8 activation (vICA), our data indicate that both caspase-dependent and -independent death pathways are activated in response to infection. Activation of caspase-dependent and -independent cell death responses restricted growth of vICA-deficient viruses, and vICA/pUL36 inhibited either response. Thus, these studies also reveal that the UL36 gene controls a caspase-independent cell death pathway. The impact of caspases on control of antiviral responses differed at early and late stages of macrophage differentiation. Early in differentiation, vICA-deficient virus-induced cell death was dependent on caspases and inhibited by the pan-caspase inhibitor z-VAD(OMe)-fluoromethyl ketone. In contrast, virus-induced death at late times of differentiation was caspase independent. Additional unlabeled and fluorescent inhibitors indicated that caspase-8 promoted death from within infected cells at early but not late stages of differentiation. These data highlight the multifunctional role of vICA/pUL36 as HCMV encounters various antiviral responses during macrophage differentiation.
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Herpesviruses and autophagy: catch me if you can! Viruses 2010; 2:314-333. [PMID: 21994613 PMCID: PMC3185561 DOI: 10.3390/v2010314] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/19/2010] [Accepted: 01/22/2010] [Indexed: 02/07/2023] Open
Abstract
Autophagy is an evolutionarily conserved cellular degradation pathway involving the digestion of intracellular components via the lysosomal pathway. The autophagic pathway constitutively maintains cellular homeostasis by recycling cytoplasmic organelles and proteins, but it is also stimulated by environmental stress conditions, such as starvation, oxidative stress, and the accumulation of misfolded proteins. It also acts as a cellular defense mechanism against microorganisms by contributing to both the innate and adaptive immunity, and by eliminating intracellular pathogens (xenophagy). There is growing evidence that host cells try to control Herpesvirus infections by activating the autophagic machinery. However, it is well-known that Herpesviruses are smart pathogens and several, such as HSV-1, HCMV and HHV-8, are known to have developed numerous defense strategies for evading the host’s immune response. Inhibition of the antiviral autophagic mechanism has also been reported. Autophagy has also been shown to enhance the major histocompatibility complex presentation of at least two viral proteins, the EBV-encoded EBNA-1 and the HSV-1 encoded gB. In this review, we present an overview of recent advances in our understanding of the complex interplay between autophagy and Herpesviruses.
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Paulus C, Nevels M. The human cytomegalovirus major immediate-early proteins as antagonists of intrinsic and innate antiviral host responses. Viruses 2009; 1:760-79. [PMID: 21994568 PMCID: PMC3185523 DOI: 10.3390/v1030760] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 11/04/2009] [Accepted: 11/05/2009] [Indexed: 12/21/2022] Open
Abstract
The major immediate-early (IE) gene of human cytomegalovirus (CMV) is believed to have a decisive role in acute infection and its activity is an important indicator of viral reactivation from latency. Although a variety of gene products are expressed from this region, the 72-kDa IE1 and the 86-kDa IE2 nuclear phosphoproteins are the most abundant and important. Both proteins have long been recognized as promiscuous transcriptional regulators. More recently, a critical role of the IE1 and IE2 proteins in counteracting non-adaptive host cell defense mechanisms has been revealed. In this review we will briefly summarize the available literature on IE1- and IE2-dependent mechanisms contributing to CMV evasion from intrinsic and innate immune responses.
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Affiliation(s)
- Christina Paulus
- Institute for Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany; E-Mail:
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Abstract
Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that infects alveolar macrophages following aerosol transmission. Lung macrophages provide a critical intracellular niche that is required for Mtb to establish infection in the human host. This parasitic relationship is made possible by the capacity of Mtb to block phagosome maturation following entry into the host macrophage, creating an environment that supports bacillary replication. Apoptosis is increasingly understood to play a role in host defense against intracellular pathogens including viruses, fungi, protozoa and bacteria. In the last 15 years an understanding of the role that macrophage apoptosis plays in TB has begun to emerge. Here we review the history and current state of the art of this topic and we offer a model of the macrophage-pathogen interaction that takes into the account the complexities of programmed cell death and the relationship between various death signaling pathways and host defense in TB.
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Affiliation(s)
- Jinhee Lee
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Michelle Hartman
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Hardy Kornfeld
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
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The story of human cytomegalovirus and cancer: increasing evidence and open questions. Neoplasia 2009; 11:1-9. [PMID: 19107226 DOI: 10.1593/neo.81178] [Citation(s) in RCA: 211] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 10/16/2008] [Accepted: 10/16/2008] [Indexed: 02/08/2023] Open
Abstract
Although human cytomegalovirus (HCMV) is generally not regarded to be an oncogenic virus, HCMV infection has been implicated in malignant diseases from different cancer entities. On the basis of our experimental findings, we developed the concept of "oncomodulation" to better explain the role of HCMV in cancer. Oncomodulation means that HCMV infects tumor cells and increases their malignancy. By this concept, HCMV was proposed to be a therapeutic target in a fraction of cancer patients. However, the clinical relevance of HCMV-induced oncomodulation remains to be clarified. One central question that has to be definitively answered is if HCMV establishes persistent virus replication in tumor cells or not. In our eyes, recent clinical findings from different groups in glioblastoma patients and especially the detection of a correlation between the numbers of HCMV-infected glioblastoma cells and tumor stage (malignancy) strongly increase the evidence that HCMV may exert oncomodulatory effects. Here, we summarize the currently available knowledge about the molecular mechanisms that may contribute to oncomodulation by HCMV as well as the clinical findings that suggest that a fraction of tumors from different entities is indeed infected with HCMV.
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Miller-Kittrell M, Sparer TE. Feeling manipulated: cytomegalovirus immune manipulation. Virol J 2009; 6:4. [PMID: 19134204 PMCID: PMC2636769 DOI: 10.1186/1743-422x-6-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 01/09/2009] [Indexed: 02/03/2023] Open
Abstract
No one likes to feel like they have been manipulated, but in the case of cytomegalovirus (CMV) immune manipulation, we do not really have much choice. Whether you call it CMV immune modulation, manipulation, or evasion, the bottom line is that CMV alters the immune response in such a way to allow the establishment of latency with lifelong shedding. With millions of years of coevolution within their hosts, CMVs, like other herpesviruses, encode numerous proteins that can broadly influence the magnitude and quality of both innate and adaptive immune responses. These viral proteins include both homologues of host proteins, such as MHC class I or chemokine homologues, and proteins with little similarity to any other known proteins, such as the chemokine binding protein. Although a strong immune response is launched against CMV, these virally encoded proteins can interfere with the host's ability to efficiently recognize and clear virus, while others induce or alter specific immune responses to benefit viral replication or spread within the host. Modulation of host immunity allows survival of both the virus and the host. One way of describing it would be a kind of "mutually assured survival" (as opposed to MAD, Mutually Assured Destruction). Evaluation of this relationship provides important insights into the life cycle of CMV as well as a greater understanding of the complexity of the immune response to pathogens in general.
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Affiliation(s)
- Mindy Miller-Kittrell
- Department of Microbiology, University of Tennessee, 1414 Cumberland Ave, Knoxville, TN, USA.
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