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Romero N, Van Waesberghe C, Favoreel HW. Pseudorabies Virus Infection of Epithelial Cells Leads to Persistent but Aberrant Activation of the NF-κB Pathway, Inhibiting Hallmark NF-κB-Induced Proinflammatory Gene Expression. J Virol 2020; 94:e00196-20. [PMID: 32132236 PMCID: PMC7199412 DOI: 10.1128/jvi.00196-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 02/27/2020] [Indexed: 02/03/2023] Open
Abstract
The nuclear factor kappa B (NF-κB) is a potent transcription factor, activation of which typically results in robust proinflammatory signaling and triggering of fast negative feedback modulators to avoid excessive inflammatory responses. Here, we report that infection of epithelial cells, including primary porcine respiratory epithelial cells, with the porcine alphaherpesvirus pseudorabies virus (PRV) results in the gradual and persistent activation of NF-κB, illustrated by proteasome-dependent degradation of the inhibitory NF-κB regulator IκB and nuclear translocation and phosphorylation of the NF-κB subunit p65. PRV-induced persistent activation of NF-κB does not result in expression of negative feedback loop genes, like the gene for IκBα or A20, and does not trigger expression of prototypical proinflammatory genes, like the gene for tumor necrosis factor alpha (TNF-α) or interleukin-6 (IL-6). In addition, PRV infection inhibits TNF-α-induced canonical NF-κB activation. Hence, PRV infection triggers persistent NF-κB activation in an unorthodox way and dramatically modulates the NF-κB signaling axis, preventing typical proinflammatory gene expression and the responsiveness of cells to canonical NF-κB signaling, which may aid the virus in modulating early proinflammatory responses in the infected host.IMPORTANCE The NF-κB transcription factor is activated via different key inflammatory pathways and typically results in the fast expression of several proinflammatory genes as well as negative feedback loop genes to prevent excessive inflammation. In the current report, we describe that infection of cells with the porcine alphaherpesvirus pseudorabies virus (PRV) triggers a gradual and persistent aberrant activation of NF-κB, which does not result in expression of hallmark proinflammatory or negative feedback loop genes. In addition, although PRV-induced NF-κB activation shares some mechanistic features with canonical NF-κB activation, it also shows remarkable differences; e.g., it is largely independent of the canonical IκB kinase (IKK) and even renders infected cells resistant to canonical NF-κB activation by the inflammatory cytokine TNF-α. Aberrant PRV-induced NF-κB activation may therefore paradoxically serve as a viral immune evasion strategy and may represent an important tool to unravel currently unknown mechanisms and consequences of NF-κB activation.
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Affiliation(s)
- Nicolás Romero
- Department of Virology, Parasitology, Immunology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Cliff Van Waesberghe
- Department of Virology, Parasitology, Immunology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Herman W Favoreel
- Department of Virology, Parasitology, Immunology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
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2
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Alternate NF-κB-Independent Signaling Reactivation of Latent HIV-1 Provirus. J Virol 2019; 93:JVI.00495-19. [PMID: 31243131 DOI: 10.1128/jvi.00495-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/16/2019] [Indexed: 12/22/2022] Open
Abstract
Current combination antiretroviral therapies (cART) are unable to eradicate HIV-1 from infected individuals because of the establishment of proviral latency in long-lived cellular reservoirs. The shock-and-kill approach aims to reactivate viral replication from the latent state (shock) using latency-reversing agents (LRAs), followed by the elimination of reactivated virus-producing cells (kill) by specific therapeutics. The NF-κB RelA/p50 heterodimer has been characterized as an essential component of reactivation of the latent HIV-1 long terminal repeat (LTR). Nevertheless, prolonged NF-κB activation contributes to the development of various autoimmune, inflammatory, and malignant disorders. In the present study, we established a cellular model of HIV-1 latency in J-Lat CD4+ T cells that stably expressed the NF-κB superrepressor IκB-α 2NΔ4 and demonstrate that conventional treatments with bryostatin-1 and hexamethylenebisacetamide (HMBA) or ionomycin synergistically reactivated HIV-1 from latency, even under conditions where NF-κB activation was repressed. Using specific calcineurin phosphatase, p38, and MEK1/MEK2 kinase inhibitors or specific short hairpin RNAs, c-Jun was identified to be an essential factor binding to the LTR enhancer κB sites and mediating the combined synergistic reactivation effect. Furthermore, acetylsalicylic acid (ASA), a potent inhibitor of the NF-κB activator kinase IκB kinase β (IKK-β), did not significantly diminish reactivation in a primary CD4+ T central memory (TCM) cell latency model. The present work demonstrates that the shock phase of the shock-and-kill approach to reverse HIV-1 latency may be achieved in the absence of NF-κB, with the potential to avoid unwanted autoimmune- and or inflammation-related side effects associated with latency-reversing strategies.IMPORTANCE The shock-and-kill approach consists of the reactivation of HIV-1 replication from latency using latency-reversing agents (LRAs), followed by the elimination of reactivated virus-producing cells. The cellular transcription factor NF-κB is considered a master mediator of HIV-1 escape from latency induced by LRAs. Nevertheless, a systemic activation of NF-κB in HIV-1-infected patients resulting from the combined administration of different LRAs could represent a potential risk, especially in the case of a prolonged treatment. We demonstrate here that conventional treatments with bryostatin-1 and hexamethylenebisacetamide (HMBA) or ionomycin synergistically reactivate HIV-1 from latency, even under conditions where NF-κB activation is repressed. Our study provides a molecular proof of concept for the use of anti-inflammatory drugs, like aspirin, capable of inhibiting NF-κB in patients under combination antiretroviral therapy during the shock-and-kill approach, to avoid potential autoimmune and inflammatory disorders that can be elicited by combinations of LRAs.
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3
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Gonçales JP, Silva Júnior JVJ, Lopes TRR, Tozetto-Mendoza TR, de Farias Guimarães D, de Morais VMS, Coêlho MRCD. Association of polymorphisms in NFκB1 promoter and NFκBIA gene with the development of antibodies against HHV-8 in HIV-infected individuals. Virology 2019; 535:255-260. [PMID: 31344550 DOI: 10.1016/j.virol.2019.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 07/03/2019] [Accepted: 07/09/2019] [Indexed: 01/01/2023]
Abstract
Human gammaherpesvirus 8 (HHV-8) is the etiologic agent of Kaposi's sarcoma, multicentric Castleman's disease and primary effusion lymphoma. Like other herpesviruses, the HHV-8 may exhibit latent or lytic cycle, both regulated by viral and host factors. Regarding host factors, we analysed the association of polymorphisms in NFkB1 promoter (NFkB1-94 ins/del ATTG) and NFκBIA gene (NFκBIA 3'UTR A→G) with the development of antibodies against latent or lytic antigens from HHV-8. The ins/del [OR 7.9 (95% CI 3.3-19.1), p < 0.001], AG [OR 12.3 (95% CI 4.3-34.9) p < 0.001], GG [OR 9.4 (95% CI 3.2-27.9), p < 0.001], ins/del + AG [OR 94.5 (95% CI 9.6-924.4), <0.0001], ins/del + GG [OR 50.4 (95% CI 5.2-482.2, p < 0.0001] and G allele [OR 3.3 (95% CI 2.0-5.6), p < 0.001] were strongly related with the presence of antibodies to lytic antigens. This is the first association of polymorphisms in NFκB1 promoter and NFκBIA gene with the development of antibodies against HHV-8.
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Affiliation(s)
- Juliana Prado Gonçales
- Virology Sector, Laboratory of Immunopathology Keizo Asami, Federal University of Pernambuco, Pernambuco, Brazil
| | - José Valter Joaquim Silva Júnior
- Virology Sector, Department of Preventive Veterinary Medicine, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Thaísa Regina Rocha Lopes
- Virology Sector, Laboratory of Immunopathology Keizo Asami, Federal University of Pernambuco, Pernambuco, Brazil
| | | | | | | | - Maria Rosangela Cunha Duarte Coêlho
- Virology Sector, Laboratory of Immunopathology Keizo Asami, Federal University of Pernambuco, Pernambuco, Brazil; Department of Physiology and Pharmacology, Center of Biosciences, Federal University of Pernambuco, Pernambuco, Brazil.
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4
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Santana AL, Oldenburg DG, Kirillov V, Malik L, Dong Q, Sinayev R, Marcu KB, White DW, Krug LT. RTA Occupancy of the Origin of Lytic Replication during Murine Gammaherpesvirus 68 Reactivation from B Cell Latency. Pathogens 2017; 6:pathogens6010009. [PMID: 28212352 PMCID: PMC5371897 DOI: 10.3390/pathogens6010009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 02/10/2017] [Indexed: 02/06/2023] Open
Abstract
RTA, the viral Replication and Transcription Activator, is essential for rhadinovirus lytic gene expression upon de novo infection and reactivation from latency. Lipopolysaccharide (LPS)/toll-like receptor (TLR)4 engagement enhances rhadinovirus reactivation. We developed two new systems to examine the interaction of RTA with host NF-kappaB (NF-κB) signaling during murine gammaherpesvirus 68 (MHV68) infection: a latent B cell line (HE-RIT) inducible for RTA-Flag expression and virus reactivation; and a recombinant virus (MHV68-RTA-Bio) that enabled in vivo biotinylation of RTA in BirA transgenic mice. LPS acted as a second stimulus to drive virus reactivation from latency in the context of induced expression of RTA-Flag. ORF6, the gene encoding the single-stranded DNA binding protein, was one of many viral genes that were directly responsive to RTA induction; expression was further increased upon treatment with LPS. However, NF-κB sites in the promoter of ORF6 did not influence RTA transactivation in response to LPS in HE-RIT cells. We found no evidence for RTA occupancy of the minimal RTA-responsive region of the ORF6 promoter, yet RTA was found to complex with a portion of the right origin of lytic replication (oriLyt-R) that contains predicted RTA recognition elements. RTA occupancy of select regions of the MHV-68 genome was also evaluated in our novel in vivo RTA biotinylation system. Streptavidin isolation of RTA-Bio confirmed complex formation with oriLyt-R in LPS-treated primary splenocytes from BirA mice infected with MHV68 RTA-Bio. We demonstrate the utility of reactivation-inducible B cells coupled with in vivo RTA biotinylation for mechanistic investigations of the interplay of host signaling with RTA.
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Affiliation(s)
- Alexis L Santana
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, NY 10016, USA.
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA.
| | | | - Varvara Kirillov
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Laraib Malik
- Department of Computer Science, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Qiwen Dong
- Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Roman Sinayev
- Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Kenneth B Marcu
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA.
- Biomedical Research Foundation Academy of Athens (BRFAA), Athens 115 27, Greece.
- Biochemistry and Cell Biology Dept., Stony Brook University, Stony Brook, NY 11794, USA.
- Department of Pathology, Health Sciences Center, Stony Brook University, Stony Brook, NY 11794, USA.
| | | | - Laurie T Krug
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA.
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Xue M, Yao S, Hu M, Li W, Hao T, Zhou F, Zhu X, Lu H, Qin D, Yan Q, Zhu J, Gao SJ, Lu C. HIV-1 Nef and KSHV oncogene K1 synergistically promote angiogenesis by inducing cellular miR-718 to regulate the PTEN/AKT/mTOR signaling pathway. Nucleic Acids Res 2014; 42:9862-79. [PMID: 25104021 PMCID: PMC4150761 DOI: 10.1093/nar/gku583] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/18/2014] [Accepted: 06/18/2014] [Indexed: 12/14/2022] Open
Abstract
Kaposi's sarcoma (KS) is an AIDS-defining cancer with aberrant neovascularization caused by KS-associated herpesvirus (KSHV). Although the interaction between HIV-1 and KSHV plays a pivotal role in promoting the aggressive manifestations of KS, the pathogenesis underlying AIDS-KS remains largely unknown. Here we examined HIV-1 Nef protein promotion of KSHV oncoprotein K1-induced angiogenesis. We showed that both internalized and ectopic expression of Nef in endothelial cells synergized with K1 to facilitate vascular tube formation and cell proliferation, and enhance angiogenesis in a chicken CAM model. In vivo experiments further indicated that Nef accelerated K1-induced angiogenesis and tumorigenesis in athymic nu/nu mice. Mechanistic studies revealed that Nef and K1 synergistically activated PI3K/AKT/mTOR signaling by downregulating PTEN. Furthermore, Nef and K1 induced cellular miR-718, which inhibited PTEN expression by directly targeting a seed sequence in the 3' UTR of its mRNA. Inhibition of miR-718 expression increased PTEN synthesis and suppressed the synergistic effect of Nef- and K1-induced angiogenesis and tumorigenesis. These results indicate that, by targeting PTEN, miR-718 mediates Nef- and K1-induced angiogenesis via activation of AKT/mTOR signaling. Our results demonstrate an essential role of miR-718/AKT/mTOR axis in AIDS-KS and thus may represent an attractive therapeutic target.
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Affiliation(s)
- Min Xue
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, P.R. China Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, P.R. China Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China Department of Physiology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, P.R. China
| | - Shuihong Yao
- Medical School, Quzhou College of Technology, Quzhou 324000, P.R. China
| | - Minmin Hu
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Wan Li
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Tingting Hao
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Feng Zhou
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Xiaofei Zhu
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Hongmei Lu
- Department of Obstetrics, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, P.R. China
| | - Di Qin
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Qin Yan
- Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
| | - Jianzhong Zhu
- Cancer Virology Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA
| | - Shou-Jiang Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Chun Lu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, P.R. China Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, P.R. China Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China
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6
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Blattman NN, Lagunoff M, Blattman JN, Corey L. Nuclear factor kappa B is required for the production of infectious human herpesvirus 8 virions. Front Microbiol 2014; 5:129. [PMID: 24795700 PMCID: PMC4006053 DOI: 10.3389/fmicb.2014.00129] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 03/13/2014] [Indexed: 01/10/2023] Open
Abstract
Human herpesvirus 8 (HHV8) infection leads to potent activation of nuclear factor kappa B (NFκB) in primary and transformed cells. We used recombinant HHV8 (rKSHV.219) expressing green fluorescent protein under the constitutive cellular promoter elongation factor 2α and red fluorescent protein under an early HHV8 lytic gene promoter T1.1 to monitor replication during infection of human foreskin fibroblasts (HF), noting changes in NFκB activity. In primary HF, NFκB levels do not affect the ability of HHV8 to establish infection or maintain latency. Furthermore, there was no effect on the percent of cells undergoing reactivation from latency, and there were similar numbers of released and cell-associated HHV8 viral particles following reactivation in the presence of inhibitors. Reactivation of HHV8 in latently infected HF in the presence of NFκB inhibitors resulted in production of viral particles that did not efficiently establish infection, due to deficiencies in binding and/or entry into normally permissive cells. Exogenous expression of glycoprotein M, an envelope protein involved in viral binding and entry, was able to partially overcome the deficiency induced by NFκB inhibitors. Our data indicate that in primary cells, NFκB is not required for infection, establishment of latency, or entry into the lytic cycle, but is required for the expression of virion associated genes involved in the initial steps of virion infectivity. These studies suggest that strategies to inhibit NFκB may prevent HHV8 spread and should be considered as a potential therapeutic target for preventing HHV8 associated diseases.
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Affiliation(s)
- Negin N Blattman
- Molecular and Cellular Biology Program, University of Washington School of Medicine Seattle, WA, USA ; Infectious Diseases and Vaccinology, Arizona State University Tempe, AZ, USA
| | - Michael Lagunoff
- Departments of Microbiology, University of Washington School of Medicine Seattle, WA, USA
| | - Joseph N Blattman
- Infectious Diseases and Vaccinology, Arizona State University Tempe, AZ, USA
| | - Lawrence Corey
- Molecular and Cellular Biology Program, University of Washington School of Medicine Seattle, WA, USA ; Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Seattle, WA, USA ; Departments of Medicine, University of Washington School of Medicine Seattle, WA, USA ; Departments of Laboratory Medicine, University of Washington School of Medicine Seattle, WA, USA
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7
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Ehrlich ES, Chmura JC, Smith JC, Kalu NN, Hayward GS. KSHV RTA abolishes NFκB responsive gene expression during lytic reactivation by targeting vFLIP for degradation via the proteasome. PLoS One 2014; 9:e91359. [PMID: 24614587 PMCID: PMC3948842 DOI: 10.1371/journal.pone.0091359] [Citation(s) in RCA: 31] [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: 06/17/2013] [Accepted: 02/12/2014] [Indexed: 01/08/2023] Open
Abstract
Kaposi's sarcoma herpesvirus (KSHV) is a gamma-2 herpesvirus present in all cases of Kaposi's sarcoma, primary effusion lymphoma (PEL), and some cases of multicentric Castleman's disease. Viral FLICE inhibitory protein (vFLIP) is a latently expressed gene that has been shown to be essential for survival of latently infected PEL cells by activating the NFκB pathway. Inhibitors of either vFLIP expression or the NFĸB pathway result in enhanced lytic reactivation and apoptosis. We have observed a decrease in vFLIP protein levels and of NFκB activation in the presence of the KSHV lytic switch protein RTA. Whereas vFLIP alone induced expression of the NFĸB responsive genes ICAM1 and TNFα, inclusion of RTA decreased vFLIP induced ICAM1 and TNFα expression in both co-transfected 293T cells and in doxycycline induced TREx BCBL1 cells. RTA expression resulted in proteasome dependent destabilization of vFLIP. Neither RTA ubiquitin E3 ligase domain mutants nor a dominant-negative RAUL mutant abrogated this effect, while RTA truncation mutants did, suggesting that RTA recruits a novel cellular ubiquitin E3 ligase to target vFLIP for proteasomal degradation, allowing for inhibition of NFĸB responsive gene expression early during lytic reactivation.
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Affiliation(s)
- Elana S. Ehrlich
- Viral Oncology Program, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (ESE); (GSH)
| | - Jennifer C. Chmura
- Department of Biological Sciences, Towson University, Towson, Maryland, United States of America
| | - John C. Smith
- Department of Biological Sciences, Towson University, Towson, Maryland, United States of America
| | - Nene N. Kalu
- Viral Oncology Program, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Gary S. Hayward
- Viral Oncology Program, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (ESE); (GSH)
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8
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IκB kinase ε targets interferon regulatory factor 1 in activated T lymphocytes. Mol Cell Biol 2014; 34:1054-65. [PMID: 24396068 DOI: 10.1128/mcb.01161-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
IκB kinase ε (IKK-ε) has an essential role as a regulator of innate immunity, functioning downstream of pattern recognition receptors to modulate NF-κB and interferon (IFN) signaling. In the present study, we investigated IKK-ε activation following T cell receptor (TCR)/CD28 stimulation of primary CD4(+) T cells and its role in the stimulation of a type I IFN response. IKK-ε was activated following TCR/CD28 stimulation of primary CD4(+) T cells; however, in T cells treated with poly(I·C), TCR/CD28 costimulation blocked induction of IFN-β transcription. We demonstrated that IKK-ε phosphorylated the transcription factor IFN regulatory factor 1 (IRF-1) at amino acid (aa) 215/219/221 in primary CD4(+) T cells and blocked its transcriptional activity. At the mechanistic level, IRF-1 phosphorylation impaired the physical interaction between IRF-1 and the NF-κB RelA subunit and interfered with PCAF-mediated acetylation of NF-κB RelA. These results demonstrate that TCR/CD28 stimulation of primary T cells stimulates IKK-ε activation, which in turn contributes to suppression of IFN-β production.
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9
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Xue M, Guo Y, Yan Q, Qin D, Lu C. Preparation and application of polyclonal antibodiesagainst KSHV v-cyclin. J Biomed Res 2013; 27:421-9. [PMID: 24086175 PMCID: PMC3783827 DOI: 10.7555/jbr.27.20120085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 11/20/2012] [Accepted: 12/04/2012] [Indexed: 12/12/2022] Open
Abstract
We prepared rabbit polyclonal antibodies against Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded v-cyclin (ORF 72) and detected the natural viral protein using these polyclonal antibodies. Three antigenic polypeptides of v-cyclin were designed and synthesized. A fragment of the v-cyclin gene was cloned into a eukaryotic expression vector pEF-MCS-Flag-IRES/Puro to construct a recombinant vector, pEF v-cyclin. Then, pEF v-cyclin was transfected into 293T and EA.hy926 cells to obtain v-cyclin-Flag fusion proteins. Six New Zealand white rabbits were immunized with KLH-conjugated peptides to generate polyclonal antibodies against v-cyclin. The polyclonal antibodies were then characterized by ELISA and Western blotting assays. Finally, the polyclonal antibodies against v-cyclin were used to detect natural viral protein expressed in BCBL-1, BC-3, and JSC-1 cells. The results showed that using the Flag antibody, v-cyclin-Flag fusion protein was detected in 293T and EA.hy926 cells transfected with pEF-v-cyclin. Furthermore, ELISA showed that the titer of the induced polyclonal rabbit anti-v-cyclin antibodies was higher than 1:8,000. In Western blotting assays, the antibodies reacted specifically with the v-cyclin-Flag fusion protein as well as the natural viral protein. The recombinant expression vector pEF-v-cyclin was constructed successfully, and the polyclonal antibodies prepared can be used for various biological tests including ELISA and Western blotting assays.
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Affiliation(s)
- Min Xue
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing 210029, P. R. China; ; Department of Physiology, Xuzhou Medical College, Xuzhou, Jiangsu, 221000, P. R. China; Jiangsu 223300, China
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10
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Zhou F, Xue M, Qin D, Zhu X, Wang C, Zhu J, Hao T, Cheng L, Chen X, Bai Z, Feng N, Gao SJ, Lu C. HIV-1 Tat promotes Kaposi's sarcoma-associated herpesvirus (KSHV) vIL-6-induced angiogenesis and tumorigenesis by regulating PI3K/PTEN/AKT/GSK-3β signaling pathway. PLoS One 2013; 8:e53145. [PMID: 23301033 PMCID: PMC3534639 DOI: 10.1371/journal.pone.0053145] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 11/23/2012] [Indexed: 12/22/2022] Open
Abstract
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is etiologically associated with KS, the most common AIDS-related malignancy. KS is characterized by vast angiogenesis and hyperproliferative spindle cells. We have previously reported that HIV-1 Tat can trigger KSHV reactivation and accelerate Kaposin A-induced tumorigenesis. Here, we explored Tat promotion of KSHV vIL-6-induced angiogenesis and tumorigenesis. Tat promotes vIL-6-induced cell proliferation, cellular transformation, vascular tube formation and VEGF production in culture. Tat enhances vIL-6-induced angiogenesis and tumorigenesis of fibroblasts and human endothelial cells in a chicken chorioallantoic membrane (CAM) model. In an allograft model, Tat promotes vIL-6-induced tumorigenesis and expression of CD31, CD34, SMA, VEGF, b-FGF, and cyclin D1. Mechanistic studies indicated Tat activates PI3K and AKT, and inactivates PTEN and GSK-3β in vIL-6 expressing cells. LY294002, a specific inhibitor of PI3K, effectively impaired Tat's promotion of vIL-6-induced tumorigenesis. Together, these results provide the first evidence that Tat might contribute to KS pathogenesis by synergizing with vIL-6, and identify PI3K/AKT pathway as a potential therapeutic target in AIDS-related KS patients.
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Affiliation(s)
- Feng Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, People’s Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People’s Republic of China
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
- Department of Pathogenic Biology and Immunology, Xuzhou Medical College, Xuzhou, Jiangsu, People’s Republic of China
| | - Min Xue
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
- Department of Physiology, Xuzhou Medical College, Xuzhou, Jiangsu, People’s Republic of China
| | - Di Qin
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Xiaofei Zhu
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Cong Wang
- Pathology of Department, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
| | - Jianzhong Zhu
- Cancer Virology Program, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, United States of America
| | - Tingting Hao
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Lin Cheng
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Xiuying Chen
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Zhiqiang Bai
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Ninghan Feng
- Department of Urology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
| | - Shou-Jiang Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Chun Lu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, People’s Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People’s Republic of China
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People’s Republic of China
- * E-mail:
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Narayanan A, Kehn-Hall K, Senina S, Lundberg L, Van Duyne R, Guendel I, Das R, Baer A, Bethel L, Turell M, Hartman AL, Das B, Bailey C, Kashanchi F. Curcumin inhibits Rift Valley fever virus replication in human cells. J Biol Chem 2012; 287:33198-214. [PMID: 22847000 DOI: 10.1074/jbc.m112.356535] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Rift Valley fever virus (RVFV) is an arbovirus that is classified as a select agent, an emerging infectious virus, and an agricultural pathogen. Understanding RVFV-host interactions is imperative to the design of novel therapeutics. Here, we report that an infection by the MP-12 strain of RVFV induces phosphorylation of the p65 component of the NFκB cascade. We demonstrate that phosphorylation of p65 (serine 536) involves phosphorylation of IκBα and occurs through the classical NFκB cascade. A unique, low molecular weight complex of the IKK-β subunit can be observed in MP-12-infected cells, which we have labeled IKK-β2. The IKK-β2 complex retains kinase activity and phosphorylates an IκBα substrate. Inhibition of the IKK complex using inhibitors impairs viral replication, thus alluding to the requirement of an active IKK complex to the viral life cycle. Curcumin strongly down-regulates levels of extracellular infectious virus. Our data demonstrated that curcumin binds to and inhibits kinase activity of the IKK-β2 complex in infected cells. Curcumin partially exerts its inhibitory influence on RVFV replication by interfering with IKK-β2-mediated phosphorylation of the viral protein NSs and by altering the cell cycle of treated cells. Curcumin also demonstrated efficacy against ZH501, the fully virulent version of RVFV. Curcumin treatment down-regulated viral replication in the liver of infected animals. Our data point to the possibility that RVFV infection may result in the generation of novel versions of host components (such as IKK-β2) that, by virtue of altered protein interaction and function, qualify as unique therapeutic targets.
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Affiliation(s)
- Aarthi Narayanan
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110, USA
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12
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Tang Q, Qin D, Lv Z, Zhu X, Ma X, Yan Q, Zeng Y, Guo Y, Feng N, Lu C. Herpes simplex virus type 2 triggers reactivation of Kaposi's sarcoma-associated herpesvirus from latency and collaborates with HIV-1 Tat. PLoS One 2012; 7:e31652. [PMID: 22347501 PMCID: PMC3276581 DOI: 10.1371/journal.pone.0031652] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 01/16/2012] [Indexed: 01/23/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) infection was necessary but not sufficient for Kaposi's sarcoma (KS) development without other cofactors. Previously, we identified that both human immunodeficiency type 1 (HIV-1) Tat and herpes simplex virus 1 (HSV-1) were important cofactors reactivating KSHV from latency. Here, we further investigated the potential of herpes simplex virus 2 (HSV-2) to influence KSHV replication and examined the role of Tat in this procedure. We demonstrated that HSV-2 was a potentially important factor in the pathogenesis of KS, as determined by production of lytic phase mRNA transcripts, viral proteins and infectious viral particles in BCBL-1 cells. These results were further confirmed by an RNA interference experiment using small interfering RNA targeting KSHV Rta and a luciferase reporter assay testing Rta promoter-driven luciferase activity. Mechanistic studies showed that HSV-2 infection activated nuclear factor-kappa B (NF-κB) signaling pathway. Inhibition of NF-κB pathway enhanced HSV-2-mediated KSHV activation, whereas activation of NF-κB pathway suppressed KSHV replication in HSV-2-infected BCBL-1 cells. Additionally, ectopic expression of Tat enhanced HSV-2-induced KSHV replication. These novel findings suggest a role of HSV-2 in the pathogenesis of KS and provide the first laboratory evidence that Tat may participate HSV-2-mediated KSHV activation, implying the complicated pathogenesis of acquired immunodeficiency syndrome (AIDS)-related KS (AIDS-KS) patients.
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Affiliation(s)
- Qiao Tang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, People's Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Clinical Laboratory, the Affiliated Nanjing First Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Di Qin
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Zhigang Lv
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Clinical Laboratory, Jiangsu Province Official Hospital, Nanjing, People's Republic of China
| | - Xiaolei Zhu
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Xinting Ma
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qin Yan
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yi Zeng
- Department of Microbiology and Immunology, Youjiang Medical College for Nationalities, Bose, People's Republic of China
| | - Yuanyuan Guo
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Ninghan Feng
- Department of Urology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Chun Lu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, People's Republic of China
- Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, People's Republic of China
- * E-mail:
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13
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Do viral infections mimic bacterial sepsis? The role of microvascular permeability: A review of mechanisms and methods. Antiviral Res 2011; 93:2-15. [PMID: 22068147 DOI: 10.1016/j.antiviral.2011.10.019] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 10/12/2011] [Accepted: 10/22/2011] [Indexed: 12/13/2022]
Abstract
A dysregulated immune response and functional immunosuppression have been considered the major mechanisms of the bacterial sepsis syndrome. More recently, the loss of endothelial barrier function and resultant microvascular leak have been found to be a key determinant of the pathogenesis of bacterial sepsis. Whether a similar paradigm applies to systemic viral syndromes is not known. Answering this question has far-reaching implications for the development of future anti-viral therapeutic strategies. In this review, we provide an overview of the structure and function of the endothelium and how its barrier integrity is compromised in bacterial sepsis. The various in vitro and in vivo methodologies available to investigate vascular leak are reviewed. Emphasis is placed on the advantages and limitations of cell culture techniques, which represent the most commonly used methods. Within this context, we appraise recent studies of three viruses - hantavirus, human herpes virus 8 and dengue virus - that suggest microvascular leak may play a role in the pathogenesis of these viral infections. We conclude with a discussion of how endothelial barrier breakdown may occur in other viral infections such as H5N1 avian influenza virus.
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14
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Saji C, Higashi C, Niinaka Y, Yamada K, Noguchi K, Fujimuro M. Proteasome inhibitors induce apoptosis and reduce viral replication in primary effusion lymphoma cells. Biochem Biophys Res Commun 2011; 415:573-8. [PMID: 22074820 DOI: 10.1016/j.bbrc.2011.10.107] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 10/25/2011] [Indexed: 11/29/2022]
Abstract
Primary effusion lymphoma (PEL) is an aggressive neoplasm caused by Kaposi's sarcoma-associated herpesvirus (KSHV). This study provides evidence that proteasomal activity is required for both survival of PEL cells stably harboring the KSHV genome and viral replication of KSHV. We evaluated the cytotoxic effects of proteasome inhibitors on PEL cells. The proteasome inhibitors MG132, lactacystin, and proteasome inhibitor I dramatically inhibited cell proliferation and induced apoptosis of PEL cells through the accumulation of p21 and p27. Furthermore, proteasome inhibitors induced the stabilization of NF-κB inhibitory molecule (IκBα) and suppressed the transcriptional activity of NF-κB in PEL cells. The NF-κB specific inhibitor BAY11-7082 also induced apoptosis in PEL cells. The constitutive activation of NF-κB signaling is essential for the survival and growth of B cell lymphoma cells, including PEL cells. NF-κB signaling is upregulated by proteasome-dependent degradation of IκBα. The suppression of NF-κB signaling by proteasome inhibitors may contribute to the induction of apoptosis in PEL cells. In addition, proteasome activity is required for KSHV replication in KSHV latently infected PEL cells. MG132 reduced the production of progeny virus from PEL cells at low concentrations, which do not affect PEL cell growth. These findings suggest that proteasome inhibitors may represent a novel strategy for the treatment of KSHV infection and KSHV-associated lymphomas.
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Affiliation(s)
- Chiaki Saji
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan
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15
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Zhu X, Zhou F, Qin D, Zeng Y, Lv Z, Yao S, Lu C. Human immunodeficiency virus type 1 induces lytic cycle replication of Kaposi's-sarcoma-associated herpesvirus: role of Ras/c-Raf/MEK1/2, PI3K/AKT, and NF-κB signaling pathways. J Mol Biol 2011; 410:1035-51. [PMID: 21763505 DOI: 10.1016/j.jmb.2011.03.055] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Revised: 03/20/2011] [Accepted: 03/24/2011] [Indexed: 01/13/2023]
Abstract
Human immunodeficiency virus type 1 (HIV-1) infection significantly increases the risk and development of Kaposi's sarcoma (KS) in individuals infected with KS-associated herpesvirus (KSHV). Previously, we reported that HIV-1 Tat protein induced KSHV replication by modulating the Janus kinase/signal transducers and activators of transcription signaling pathway. Here, we further investigated the possible signaling pathways involved in HIV-1-induced reactivation of KSHV. We showed that HIV-1 infection of primary effusion lymphoma cell lines triggered the reactivation of KSHV, as demonstrated by the expression of KSHV replication and transcription activator, the early viral lytic protein vIL-6 and ORF59 and the production of progeny virions. By utilizing microarray gene expression analyses, transfecting a series of dominant negative mutants, and adding pharmacologic inhibitors, we identified a group of diverse cellular signaling proteins and found that HIV-1 infection of BCBL-1 cells activated phosphatidylinositol 3-kinase/AKT (also called protein kinase B, PKB) pathway and inactivated phosphatase and tensin homolog deleted on chromosome ten and glycogen synthase kinase-3β, which partially modulated HIV-1-induced KSHV reactivation. Furthermore, activation of Ras/c-Raf/MAPK/ERK kinase1/2 pathway contributed to HIV-1-induced KSHV replication. Finally, we discovered that HIV-1 infection activated nuclear factor κB signaling, which exhibits an inhibitory effect on KSHV reactivation in BCBL-1 cells. Collectively, our data demonstrated that HIV-1 infection stimulated these cell signaling pathways that, in turn, contributed to KSHV reactivation, which may be of therapeutic value in acquired immunodeficiency syndrome-related KS patients.
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Affiliation(s)
- Xiaolei Zhu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, People's Republic of China
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16
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Abstract
NF-κB is a pivotal transcription factor that controls cell survival and proliferation in diverse physiological processes. The activity of NF-κB is tightly controlled through its cytoplasmic sequestration by specific inhibitors, IκBs. Various cellular stimuli induce the activation of an IκB kinase, which phosphorylates IκBs and triggers their proteasomal degradation, causing nuclear translocation of activated NF-κB. Under normal conditions, the activation of NF-κB occurs transiently, thus ensuring rapid but temporary induction of target genes. Deregulated NF-κB activation contributes to the development of various diseases, including cancers and immunological disorders. Accumulated studies demonstrate that the NF-κB signaling pathway is a target of several human oncogenic viruses, including the human T cell leukemia virus type 1, the Kaposi sarcoma-associated herpesvirus, and the Epstein-Bar virus. These viruses encode specific oncoproteins that target different signaling components of the NF-κB pathway, leading to persistent activation of NF-κB. This chapter will discuss the molecular mechanisms by which NF-κB is activated by the viral oncoproteins.
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Affiliation(s)
- Shao-Cong Sun
- Department of Immunology, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
| | - Ethel Cesarman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065
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17
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Abstract
The life cycle of Kaposi's sarcoma-associated herpesvirus (KSHV) consists of latent and lytic replication phases. During latent infection, only a limited number of KSHV genes are expressed. However, this phase of replication is essential for persistent infection, evasion of host immune response, and induction of KSHV-related malignancies. KSHV reactivation from latency produces a wide range of viral products and infectious virions. The resulting de novo infection and viral lytic products modulate diverse cellular pathways and stromal microenvironment, which promote the development of Kaposi's sarcoma (KS). The mechanisms controlling KSHV latency and reactivation are complex, involving both viral and host factors, and are modulated by diverse environmental factors. Here, we review the cellular and molecular basis of KSHV latency and reactivation with a focus on the most recent advancements in the field.
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18
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The lytic activation of KSHV during keratinocyte differentiation is dependent upon a suprabasal position, the loss of integrin engagement, and calcium, but not the interaction of cadherins. Virology 2010; 410:17-29. [PMID: 21084105 DOI: 10.1016/j.virol.2010.10.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 08/04/2010] [Accepted: 10/13/2010] [Indexed: 12/15/2022]
Abstract
We previously found that KSHV (HHV-8) lytic activation occurs during differentiation of oral keratinocytes in organotypic raft cultures. To further investigate the spatial and temporal aspects of KSHV lytic activation and the roles of integrins, cadherins, and calcium, we used rKSHV.219-infected primary oral keratinocytes in submerged, suspension, and direct suprabasal plating, models of differentiation. We found that early keratinocyte differentiation did not activate lytic KSHV in cells attached to a substratum, with activation only occurring in suprabasal cells. Temporally, KSHV lytic expression occurred between the expression of early and late differentiation markers. Keratinocytes differentiated in suspension culture, which mimics substratum loss that occurs with stratification, activated lytic KSHV. This lytic activation was inhibited by integrin engagement, showing that integrins are a control point for KSHV reactivation. A role for cadherins was not found. Elevated extracellular calcium was necessary, but not sufficient, for lytic activation.
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Abstract
Latency is a state of cryptic viral infection associated with genomic persistence and highly restricted gene expression. Its hallmark is reversibility: under appropriate circumstances, expression of the entire viral genome can be induced, resulting in the production of infectious progeny. Among the small number of virus families capable of authentic latency, the herpesviruses stand out for their ability to produce such infections in every infected individual and for being completely dependent upon latency as a mode of persistence. Here, we review the molecular basis of latency, with special attention to the gamma-herpesviruses, in which the understanding of this process is most advanced.
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Affiliation(s)
- Samuel H Speck
- Emory Vaccine Center, Emory University, Atlanta, GA 30322, USA
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20
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NF-κB signaling modulation by EBV and KSHV. Trends Microbiol 2010; 18:248-57. [DOI: 10.1016/j.tim.2010.04.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 03/24/2010] [Accepted: 04/02/2010] [Indexed: 12/12/2022]
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21
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Dabaghmanesh N, Matsubara A, Miyake A, Nakano K, Ishida T, Katano H, Horie R, Umezawa K, Watanabe T. Transient inhibition of NF-kappaB by DHMEQ induces cell death of primary effusion lymphoma without HHV-8 reactivation. Cancer Sci 2009; 100:737-46. [PMID: 19469019 PMCID: PMC11159611 DOI: 10.1111/j.1349-7006.2009.01083.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2008] [Revised: 11/07/2008] [Accepted: 12/03/2008] [Indexed: 11/28/2022] Open
Abstract
Primary effusion lymphoma (PEL) is a refractory malignancy caused by human herpes virus 8 (HHV-8) in immunocompromised individuals. The tumor cells of PEL are characterized by constitutive NF-kappaB activation. Dehydroxymethylepoxyquinomicin (DHMEQ) is a new NF-kappaB inhibitor and is effective on various tumor cells with constitutively activated NF-kappaB. Thus, in search for a new therapeutic modality of PEL, we examined the effect of DHMEQ on PEL cells. We confirmed constitutive activation of NF-kappaB with subcomponents of p50 and p65 in PEL cell lines. DHMEQ quickly and transiently abrogated NF-kappaB activation and reduced the cell viability in dose- and time-dependent manners, inducing apoptosis through activation of both mitochondrial and membrane pathways. Array analysis revealed that DHMEQ down-regulated expression levels of NF-kappaB target genes, such as interleukin-6 (IL6), Myc, chemokine (C-C motif) receptor 5 (CCR5) and NF-kappaB1, whereas it up-regulated expression levels of some genes involved in apoptosis, and cell cycle arrest. DHMEQ did not reactivate HHV-8 lytic genes, indicating that NF-kappaB inhibition by DHMEQ did not induce virus replication. DHEMQ rescued CB-17 SCID mice xenografted with PEL cells, reducing the gross appearance of effusion. Thus, DHMEQ transiently abrogated the NF-kappaB activation, irreversibly triggering the apoptosis cascade without HHV-8 reactivation. In addition, DHMEQ could rescue the PEL-xenograft mice. Therefore, we suggest DHMEQ as a promising candidate for molecular target therapy of the PEL.
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Affiliation(s)
- Nazanin Dabaghmanesh
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
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22
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A systems biology approach to identify the combination effects of human herpesvirus 8 genes on NF-kappaB activation. J Virol 2009; 83:2563-74. [PMID: 19129458 DOI: 10.1128/jvi.01512-08] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Human herpesvirus 8 (HHV-8) is the etiologic agent of Kaposi's sarcoma and primary effusion lymphoma. Activation of the cellular transcription factor nuclear factor-kappa B (NF-kappaB) is essential for latent persistence of HHV-8, survival of HHV-8-infected cells, and disease progression. We used reverse-transfected cell microarrays (RTCM) as an unbiased systems biology approach to systematically analyze the effects of HHV-8 genes on the NF-kappaB signaling pathway. All HHV-8 genes individually (n = 86) and, additionally, all K and latent genes in pairwise combinations (n = 231) were investigated. Statistical analyses of more than 14,000 transfections identified ORF75 as a novel and confirmed K13 as a known HHV-8 activator of NF-kappaB. K13 and ORF75 showed cooperative NF-kappaB activation. Small interfering RNA-mediated knockdown of ORF75 expression demonstrated that this gene contributes significantly to NF-kappaB activation in HHV-8-infected cells. Furthermore, our approach confirmed K10.5 as an NF-kappaB inhibitor and newly identified K1 as an inhibitor of both K13- and ORF75-mediated NF-kappaB activation. All results obtained with RTCM were confirmed with classical transfection experiments. Our work describes the first successful application of RTCM for the systematic analysis of pathofunctions of genes of an infectious agent. With this approach, ORF75 and K1 were identified as novel HHV-8 regulatory molecules on the NF-kappaB signal transduction pathway. The genes identified may be involved in fine-tuning of the balance between latency and lytic replication, since this depends critically on the state of NF-kappaB activity.
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23
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Grossmann C, Ganem D. Effects of NFkappaB activation on KSHV latency and lytic reactivation are complex and context-dependent. Virology 2008; 375:94-102. [PMID: 18321555 DOI: 10.1016/j.virol.2007.12.044] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2007] [Revised: 11/19/2007] [Accepted: 12/20/2007] [Indexed: 11/16/2022]
Abstract
Like all herpesviruses, Kaposi's sarcoma-associated herpesvirus (KSHV) can produce either latent or lytic infection. The latent v-FLIP gene is a strong activator of NFkappaB, and in primary effusion lymphoma (PEL) cells, blockade of NFkappaB activation is associated with enhanced lytic gene expression, while overexpression of p65 impairs expression of reporter genes driven by lytic promoters. This has led to the suggestion that NFkappaB activation may promote latency by suppressing lytic reactivation. Here we examine in detail the effects of NFkappaB activation on KSHV replication in several cell types. In accord with earlier work, we find that inhibition of NFkappaB signaling in PEL cells is associated with enhanced lytic reactivation of KSHV. Similarly, in de novo KSHV infection of primary endothelial cells, inhibition of NFkappaB signaling leads to an increase in lytic gene expression and enhanced virion production. By contrast, KSHV-infected human foreskin fibroblasts (HFF) show no increase in spontaneous lytic reactivation when NFkappaB is inhibited. Moreover, if NFkappaB activation is always inhibitory to lytic gene expression, one might expect its activation to be suppressed during the lytic cycle. However, we find that NFkappaB signaling is strongly and consistently activated in lytically infected cells of all lineages. Together these data indicate that (i) the relationship of NFkappaB activation to latency and lytic reactivation is not uniform, but is dependent on the cellular context; and (ii) even though NFkappaB activation is inhibitory to lytic gene expression in some contexts, such inhibition is at least partially bypassed or overridden during lytic growth.
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Affiliation(s)
- Claudia Grossmann
- Howard Hughes Medical Institute, San Francisco 94143, USA; Department of Medicine, University of California, San Francisco 94143, USA; Department of Microbiology, University of California, San Francisco 94143, USA
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24
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Kaposi's sarcoma-associated herpesvirus latent gene vFLIP inhibits viral lytic replication through NF-kappaB-mediated suppression of the AP-1 pathway: a novel mechanism of virus control of latency. J Virol 2008; 82:4235-49. [PMID: 18305042 DOI: 10.1128/jvi.02370-07] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) latency is central to the evasion of host immune surveillances and induction of KSHV-related malignancies. The mechanism of KSHV latency remains unclear. Here, we show that the KSHV latent gene vFLIP promotes viral latency by inhibiting viral lytic replication. vFLIP suppresses the AP-1 pathway, which is essential for KSHV lytic replication, by activating the NF-kappaB pathway. Thus, by manipulating two convergent cellular pathways, vFLIP regulates both cell survival and KSHV lytic replication to promote viral latency. These results also indicate that the effect of the NF-kappaB pathway on KSHV replication is determined by the status of the AP-1 pathway and hence provide a mechanistic explanation for the contradictory role of the NF-kappaB pathway in KSHV replication. Since the NF-kappaB pathway is commonly activated during infection of gammaherpesviruses, these findings might have general implications for the control of gammaherpesviral latency.
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25
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Kaposi's sarcoma-associated herpesvirus transactivator RTA promotes degradation of the repressors to regulate viral lytic replication. J Virol 2008; 82:3590-603. [PMID: 18216089 DOI: 10.1128/jvi.02229-07] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV-8) RTA is an important protein involved in the induction of KSHV lytic replication from latency through activation of the lytic cascade. A number of cellular and viral proteins, including K-RBP, have been found to repress RTA-mediated transactivation and KSHV lytic replication. However, it is unclear as to how RTA overcomes the suppression during lytic reactivation. In this study, we found that RTA can induce K-RBP degradation through the ubiquitin-proteasome pathway and that two regions in RTA are responsible. Moreover, we found that RTA can promote the degradation of several other RTA repressors. RTA mutants that are defective in inducing K-RBP degradation cannot activate RTA responsive promoter as efficiently as wild-type RTA. Interference of the ubiquitin-proteasome pathway affected RTA-mediated transactivation and KSHV reactivation from latency. Our results suggest that KSHV RTA can stimulate the turnover of repressors to modulate viral reactivation. Since herpes simplex virus type 1 transactivator ICP0 and human cytomegalovirus transactivator pp71 also stimulate the degradation of cellular silencers, it is possible that the promotion of silencer degradation by viral transactivators may be a common mechanism for regulating the lytic replication of herpesviruses.
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26
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Xie J, Ajibade AO, Ye F, Kuhne K, Gao SJ. Reactivation of Kaposi's sarcoma-associated herpesvirus from latency requires MEK/ERK, JNK and p38 multiple mitogen-activated protein kinase pathways. Virology 2007; 371:139-54. [PMID: 17964626 DOI: 10.1016/j.virol.2007.09.040] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Revised: 08/17/2007] [Accepted: 09/27/2007] [Indexed: 12/22/2022]
Abstract
Lytic replication of Kaposi's sarcoma-associated herpesvirus (KSHV) promotes the progression of Kaposi's sarcoma (KS), a dominant malignancy in patients with AIDS. While 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced KSHV reactivation from latency is mediated by the protein kinase C delta and MEK/ERK mitogen-activated protein kinase (MAPK) pathways, we have recently shown that the MEK/ERK, JNK and p38 MAPK pathways modulate KSHV lytic replication during productive primary infection of human umbilical vein endothelial cells [Pan, H., Xie, J., Ye, F., Gao, S.J., 2006. Modulation of Kaposi's sarcoma-associated herpesvirus infection and replication by MEK/ERK, JNK, and p38 multiple mitogen-activated protein kinase pathways during primary infection. J. Virol. 80 (11), 5371-5382]. Here, we report that, besides the MEK/ERK pathway, the JNK and p38 MAPK pathways also mediate TPA-induced KSHV reactivation from latency. The MEK/ERK, JNK and p38 MAPK pathways were constitutively activated in latent KSHV-infected BCBL-1 cells. TPA treatment enhanced the levels of activated ERK and p38 but not those of activated JNK. Inhibitors of all three MAPK pathways reduced TPA-induced production of KSHV infectious virions in BCBL-1 cells in a dose-dependent fashion. The inhibitors blocked KSHV lytic replication at the early stage(s) of reactivation, and reduced the expression of viral lytic genes including RTA, a key immediate-early transactivator of viral lytic replication. Activation of MAPK pathways was necessary and sufficient for activating the promoter of RTA. Furthermore, we showed that the activation of RTA promoter by MAPK pathways was mediated by their downstream target AP-1. Together, these findings suggest that MAPK pathways might have general roles in regulating the life cycle of KSHV by mediating both viral infection and switch from viral latency to lytic replication.
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Affiliation(s)
- Jianping Xie
- Tumor Virology Program, Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, 8403 Floyd Curl Drive, San Antonio, TX 78229, USA
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27
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Caselli E, Fiorentini S, Amici C, Di Luca D, Caruso A, Santoro MG. Human herpesvirus 8 acute infection of endothelial cells induces monocyte chemoattractant protein 1-dependent capillary-like structure formation: role of the IKK/NF-kappaB pathway. Blood 2007; 109:2718-26. [PMID: 17138827 DOI: 10.1182/blood-2006-03-012500] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human herpesvirus 8 (HHV-8) is considered the causative agent of Kaposi sarcoma, a highly vascularized neoplasm characterized by spindle-shaped cells of endothelial origin and inflammatory cell infiltration. The cell transforming ability of HHV-8 has been associated with the activation of NF-kappaB, a nuclear factor playing a pivotal role in promoting inflammation and cell proliferation; however, little is known about NF-kappaB activation during acute HHV-8 infection. In the present study, we used a recently established in vitro model of HHV-8 acute productive infection in endothelial cells to investigate the effect of HHV-8 on NF-kappaB activity and function. HHV-8 rapidly and potently induced NF-kappaB activity in endothelial cells via stimulation of the IkappaB kinase (IKK). Following IKK activation, HHV-8 selectively triggered the production of high levels of monocyte chemoattractant protein 1 (MCP-1), whereas it did not affect the expression of other NF-kappaB-dependent proinflammatory proteins, including TNF-alpha, IL-8, and RANTES. Deletion of NF-kappaB-binding sites in the MCP-1 enhancer resulted in significant inhibition of HHV-8-induced transcription. Furthermore, MCP-1 production was accompanied by virus-induced capillary-like structure formation at early stages of infection. The results suggest that HHV-8-induced MCP-1 may play an important role in promoting inflammation and pathogenic angiogenesis typical of HHV-8-associated lesions.
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Affiliation(s)
- Elisabetta Caselli
- Section of Microbiology, Department of Experimental and Diagnostic Medicine, University of Ferrara, Italy
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28
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Sahni SK. Endothelial cell infection and hemostasis. Thromb Res 2007; 119:531-49. [PMID: 16875715 DOI: 10.1016/j.thromres.2006.06.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 06/09/2006] [Accepted: 06/09/2006] [Indexed: 01/24/2023]
Abstract
As an important component of the vasculature, endothelial cell lining covers the inner surface of blood vessels and provides an active barrier interface between the vascular and perivascular compartments. In addition to maintaining vasomotor equilibrium and organ homeostasis and communicating with circulating blood cells, the vascular endothelium also serves as the preferred target for a number of infectious agents. This review article focuses on the roles of interactions between vascular endothelial cells and invading pathogens and resultant endothelial activation in the pathogenesis of important human diseases with viral and bacterial etiologies. In this perspective, the signal transduction events that regulate vascular inflammation and basis for endothelial cell tropism exhibited by certain specific viruses and pathogenic bacteria are also discussed.
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Affiliation(s)
- Sanjeev K Sahni
- Department of Medicine, Hematology-Oncology Unit, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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29
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Greene W, Kuhne K, Ye F, Chen J, Zhou F, Lei X, Gao SJ. Molecular biology of KSHV in relation to AIDS-associated oncogenesis. Cancer Treat Res 2007; 133:69-127. [PMID: 17672038 PMCID: PMC2798888 DOI: 10.1007/978-0-387-46816-7_3] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
KSHV has been established as the causative agent of KS, PEL, and MCD, malignancies occurring more frequently in AIDS patients. The aggressive nature of KSHV in the context of HIV infection suggests that interactions between the two viruses enhance pathogenesis. KSHV latent infection and lytic reactivation are characterized by distinct gene expression profiles, and both latency and lytic reactivation seem to be required for malignant progression. As a sophisticated oncogenic virus, KSHV has evolved to possess a formidable repertoire of potent mechanisms that enable it to target and manipulate host cell pathways, leading to increased cell proliferation, increased cell survival, dysregulated angiogenesis, evasion of immunity, and malignant progression in the immunocompromised host. Worldwide, approximately 40.3 million people are currently living with HIV infection. Of these, a significant number are coinfected with KSHV. The complex interplay between the two viruses dramatically elevates the risk for development of KSHV-induced malignancies, KS, PEL, and MCD. Although HAART significantly reduces HIV viral load, the entire T-cell repertoire and immune function may not be completely restored. In fact, clinically significant immune deficiency is not necessary for the induction of KSHV-related malignancy. Because of variables such as lack of access to therapy noncompliance with prescribed treatment, failure to respond to treatment and the development of drug-resistant strains of HIV, KSHV-induced malignancies will continue to present as major health concerns.
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Affiliation(s)
- Whitney Greene
- Tiumor Virology Program, Children's Cancer Research Institute, Department of Pediatrics, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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30
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Hiscott J, Nguyen TLA, Arguello M, Nakhaei P, Paz S. Manipulation of the nuclear factor-kappaB pathway and the innate immune response by viruses. Oncogene 2006; 25:6844-67. [PMID: 17072332 PMCID: PMC7100320 DOI: 10.1038/sj.onc.1209941] [Citation(s) in RCA: 207] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Viral and microbial constituents contain specific motifs or pathogen-associated molecular patterns (PAMPs) that are recognized by cell surface- and endosome-associated Toll-like receptors (TLRs). In addition, intracellular viral double-stranded RNA is detected by two recently characterized DExD/H box RNA helicases, RIG-I and Mda-5. Both TLR-dependent and -independent pathways engage the IkappaB kinase (IKK) complex and related kinases TBK-1 and IKKvarepsilon. Activation of the nuclear factor kappaB (NF-kappaB) and interferon regulatory factor (IRF) transcription factor pathways are essential immediate early steps of immune activation; as a result, both pathways represent prime candidates for viral interference. Many viruses have developed strategies to manipulate NF-kappaB signaling through the use of multifunctional viral proteins that target the host innate immune response pathways. This review discusses three rapidly evolving areas of research on viral pathogenesis: the recognition and signaling in response to virus infection through TLR-dependent and -independent mechanisms, the involvement of NF-kappaB in the host innate immune response and the multitude of strategies used by different viruses to short circuit the NF-kappaB pathway.
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Affiliation(s)
- J Hiscott
- Terry Fox Molecular Oncology Group, Lady Davis Institute for Medical Research, McGill University, Montreal, Canada.
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31
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Bernal-Mizrachi L, Lovly CM, Ratner L. The role of NF-{kappa}B-1 and NF-{kappa}B-2-mediated resistance to apoptosis in lymphomas. Proc Natl Acad Sci U S A 2006; 103:9220-5. [PMID: 16751281 PMCID: PMC1482593 DOI: 10.1073/pnas.0507809103] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The NF-kappaB pathways have been implicated in tumorigenesis in several lymphoid malignancies, including non-Hodgkin's and Hodgkin's lymphomas. However, the antiapoptotic functions and the mechanism responsible for signaling through each NF-kappaB pathway remain to be elucidated. In the current study, lymphoma cell lines with constitutively active NF-kappaB were found to be resistant to inducers of the extrinsic and intrinsic apoptosis pathways. Resistance to cell death resulted from blocks early and late in the apoptosis cascade. Several NF-kappaB target genes were overexpressed in these cell lines, including Bcl-xL, Fas-associated death domain-like IL-1beta-converting enzyme inhibitor protein, cellular inhibitor of apoptosis, and X inhibitor of apoptosis. Inhibition of the canonical or noncanonical NF-kappaB pathways with small interfering RNAs or adenovirus expressing a stable form of inhibitor of NF-kappaB (IkappaB) enhanced sensitivity to apoptosis inducers and resulted in lower levels of Bcl-xL or Fas-associated death domain-like IL-1beta-converting enzyme inhibitor protein, cellular inhibitor of apoptosis, and X inhibitor of apoptosis. These findings demonstrate an important role of both NF-kappaB pathways in mediating resistance to apoptosis and distinctive antiapoptotic downstream target gene profiles responsible for this effect.
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Affiliation(s)
- Leon Bernal-Mizrachi
- *Division of Molecular Oncology, Departments of
- Medicine
- Division of Hematology and Oncology, Department of Medicine, Emory University, Atlanta, GA 30322
| | | | - Lee Ratner
- *Division of Molecular Oncology, Departments of
- Medicine
- Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110; and
- To whom correspondence should be addressed. E-mail:
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