1
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An Expanded Interplay Network between NF-κB p65 (RelA) and E2F1 Transcription Factors: Roles in Physiology and Pathology. Cancers (Basel) 2022; 14:cancers14205047. [PMID: 36291831 PMCID: PMC9600032 DOI: 10.3390/cancers14205047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/30/2022] [Accepted: 10/10/2022] [Indexed: 11/17/2022] Open
Abstract
Transcription Factors (TFs) are the main regulators of gene expression, controlling among others cell homeostasis, identity, and fate. TFs may either act synergistically or antagonistically on nearby regulatory elements and their interplay may activate or repress gene expression. The family of NF-κB TFs is among the most important TFs in the regulation of inflammation, immunity, and stress-like responses, while they also control cell growth and survival, and are involved in inflammatory diseases and cancer. The family of E2F TFs are major regulators of cell cycle progression in most cell types. Several studies have suggested the interplay between these two TFs in the regulation of numerous genes controlling several biological processes. In the present study, we compared the genomic binding landscape of NF-κB RelA/p65 subunit and E2F1 TFs, based on high throughput ChIP-seq and RNA-seq data in different cell types. We confirmed that RelA/p65 has a binding profile with a high preference for distal enhancers bearing active chromatin marks which is distinct to that of E2F1, which mostly generates promoter-specific binding. Moreover, the RelA/p65 subunit and E2F1 cistromes have limited overlap and tend to bind chromatin that is in an active state even prior to immunogenic stimulation. Finally, we found that a fraction of the E2F1 cistrome is recruited by NF-κΒ near pro-inflammatory genes following LPS stimulation in immune cell types.
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2
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Lim AL, Moos P, Pond CD, Larson EC, Martins LJ, Szaniawski MA, Planelles V, Barrows LR. HIV-1 provirus transcription and translation in macrophages differs from pre-integrated cDNA complexes and requires E2F transcriptional programs. Virulence 2022; 13:386-413. [PMID: 35166645 PMCID: PMC8855869 DOI: 10.1080/21505594.2022.2031583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
HIV-1 cDNA pre-integration complexes persist for weeks in macrophages and remain transcriptionally active. While previous work has focused on the transcription of HIV-1 genes; our understanding of the cellular milieu that accompanies viral production is incomplete. We have used an in vitro system to model HIV-1 infection of macrophages, and single-cell RNA sequencing (scRNA-seq) to compare the transcriptomes of uninfected cells, cells harboring pre-integration complexes (PIC), and those containing integrated provirus and making late HIV proteins. scRNA-seq can distinguish between provirus and PIC cells because their background transcriptomes vary dramatically. PIC cell transcriptomes are characterized by NFkB and AP-1 promoted transcription, while transcriptomes of cells transcribing from provirus are characterized by E2F family transcription products. We also find that the transcriptomes of PIC cells and Bystander cells (defined as cells not producing any HIV transcript and thus presumably not infected) are indistinguishable except for the presence of HIV-1 transcripts. Furthermore, the presence of pathogen alters the transcriptome of the uninfected Bystander cells, so that they are distinguishable from true control cells (cells not exposed to any pathogen). Therefore, a single cell comparison of transcriptomes from provirus and PIC cells provides a new understanding of the transcriptional changes that accompany HIV-1 integration.
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Affiliation(s)
- Albebson L Lim
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA.,Marine Science Institute, University of the Philippines Diliman, Quezon City, Philippines
| | - Philip Moos
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA
| | - Christopher D Pond
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA
| | - Erica C Larson
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA.,Department of Microbiology & Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Laura J Martins
- Department of Pathology, University of Utah, Salt Lake City, Utah, USA
| | | | - Vicente Planelles
- Department of Pathology, University of Utah, Salt Lake City, Utah, USA
| | - Louis R Barrows
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA
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3
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Lauer AN, Scholtysik R, Beineke A, Baums CG, Klose K, Valentin-Weigand P, Ishikawa H, Schroten H, Klein-Hitpass L, Schwerk C. A Comparative Transcriptome Analysis of Human and Porcine Choroid Plexus Cells in Response to Streptococcus suis Serotype 2 Infection Points to a Role of Hypoxia. Front Cell Infect Microbiol 2021; 11:639620. [PMID: 33763387 PMCID: PMC7982935 DOI: 10.3389/fcimb.2021.639620] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/01/2021] [Indexed: 11/14/2022] Open
Abstract
Streptococcus suis (S. suis) is an important opportunistic pathogen, which can cause septicemia and meningitis in pigs and humans. Previous in vivo observations in S. suis-infected pigs revealed lesions at the choroid plexus (CP). In vitro experiments with primary porcine CP epithelial cells (PCPEC) and human CP epithelial papilloma (HIBCPP) cells demonstrated that S. suis can invade and traverse the CP epithelium, and that the CP contributes to the inflammatory response via cytokine expression. Here, next generation sequencing (RNA-seq) was used to compare global transcriptome profiles of PCPEC and HIBCPP cells challenged with S. suis serotype (ST) 2 infected in vitro, and of pigs infected in vivo. Identified differentially expressed genes (DEGs) were, amongst others, involved in inflammatory responses and hypoxia. The RNA-seq data were validated via quantitative PCR of selected DEGs. Employing Gene Set Enrichment Analysis (GSEA), 18, 28, and 21 enriched hallmark gene sets (GSs) were identified for infected HIBCPP cells, PCPEC, and in the CP of pigs suffering from S. suis ST2 meningitis, respectively, of which eight GSs overlapped between the three different sample sets. The majority of these GSs are involved in cellular signaling and pathways, immune response, and development, including inflammatory response and hypoxia. In contrast, suppressed GSs observed during in vitro and in vivo S. suis ST2 infections included those, which were involved in cellular proliferation and metabolic processes. This study suggests that similar cellular processes occur in infected human and porcine CP epithelial cells, especially in terms of inflammatory response.
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Affiliation(s)
- Alexa N Lauer
- Pediatric Infectious Diseases, Department of Pediatrics, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Rene Scholtysik
- Institute for Cell Biology, University Hospital Essen, Essen, Germany
| | - Andreas Beineke
- Institute for Pathology, University of Veterinary Medicine, Hannover, Germany
| | - Christoph Georg Baums
- Faculty of Veterinary Medicine, Institute of Bacteriology and Mycology, Leipzig University, Leipzig, Germany
| | - Kristin Klose
- Faculty of Veterinary Medicine, Institute of Veterinary Pathology, Leipzig University, Leipzig, Germany
| | | | - Hiroshi Ishikawa
- Laboratory of Clinical Regenerative Medicine, Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Horst Schroten
- Pediatric Infectious Diseases, Department of Pediatrics, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | | | - Christian Schwerk
- Pediatric Infectious Diseases, Department of Pediatrics, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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4
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Ma D, Lian F, Wang X. PLCG2 promotes hepatocyte proliferation in vitro via NF-κB and ERK pathway by targeting bcl2, myc and ccnd1. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2020; 47:3786-3792. [PMID: 31549850 DOI: 10.1080/21691401.2019.1669616] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Phospholipase Cγ2 (PLCG2) has been implicated in the regulation of cell proliferation, transformation, and tumor growth. In this study, we investigate the mechanism of PLCG2 action using a short interference RNA (siRNA) method. The effects of PLCG2 on rat liver BRL-3A cells treated siRNA were studied by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT assay), bromodeoxyuridine (BrdU) labelling assay, flow cytometry method (FCM), quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. The results showed when PLCG2 was reduced, cell vitality and proliferation rate were significantly decreased (p < .05 vs. control). FCM analysis showed that the number of cell division phase (G2 + M) was declined (p < .05 vs. control). RT-PCR and western blot revealed that the expression of signalling related genes NF-κB, FOS, JUN and ELK, target genes BCL2, CCNB1 and CCND1 were remarkably down-regulated in cells treated with PLCG2 siRNAs. Based on these results, we conclude PLCG2 plays an important role in rat liver cell proliferation via ERK and NF-κB pathway by regulating the expression of BCl2, MYC and CCND1.
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Affiliation(s)
- Donghui Ma
- Department of Interventional Radiology and Vascular Surgery, The First Affiliated Hospital of Jinan University , Guangzhou , Guangdong , China
| | - Fang Lian
- Department of Clinical Laboratory, The Second Affiliated Hospital of Hainan Medical University , Haikou , Hainan , China
| | - Xiaobai Wang
- Department of Interventional Radiology and Vascular Surgery, The First Affiliated Hospital of Jinan University , Guangzhou , Guangdong , China
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5
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Polouliakh N, Horton P, Shibanai K, Takata K, Ludwig V, Ghosh S, Kitano H. Sequence homology in eukaryotes (SHOE): interactive visual tool for promoter analysis. BMC Genomics 2018; 19:715. [PMID: 30261835 PMCID: PMC6161448 DOI: 10.1186/s12864-018-5101-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/21/2018] [Indexed: 02/06/2023] Open
Abstract
Background Microarray and DNA-sequencing based technologies continue to produce enormous amounts of data on gene expression. This data has great potential to illuminate our understanding of biology and medicine, but the data alone is of limited value without computational tools to allow human investigators to visualize and interpret it in the context of their problem of interest. Results We created a web server called SHOE that provides an interactive, visual presentation of the available evidence of transcriptional regulation and gene co-expression to facilitate its exploration and interpretation. SHOE predicts the likely transcription factor binding sites in orthologous promoters of humans, mice, and rats using the combined information of 1) transcription factor binding preferences (position-specific scoring matrix (PSSM) libraries such as Transfac32, Jaspar, HOCOMOCO, ChIP-seq, SELEX, PBM, and iPS-reprogramming factor), 2) evolutionary conservation of putative binding sites in orthologous promoters, and 3) co-expression tendencies of gene pairs based on 1,714 normal human cells selected from the Gene Expression Omnibus Database. Conclusion SHOE enables users to explore potential interactions between transcription factors and target genes via multiple data views, discover transcription factor binding motifs on top of gene co-expression, and visualize genes as a network of gene and transcription factors on its native gadget GeneViz, the CellDesigner pathway analyzer, and the Reactome database to search the pathways involved. As we demonstrate here when using the CREB1 and Nf-κB datasets, SHOE can reliably identify experimentally verified interactions and predict plausible novel ones, yielding new biological insights into the gene regulatory mechanisms involved. SHOE comes with a manual describing how to run it on a local PC or via the Garuda platform (www.garuda-alliance.org), where it joins other popular gadgets such as the CellDesigner pathway analyzer and the Reactome database, as part of analysis workflows to meet the growing needs of molecular biologists and medical researchers. SHOE is available from the following URL http://ec2-54-150-223-65.ap-northeast-1.compute.amazonaws.com A video demonstration of SHOE can be found here: https://www.youtube.com/watch?v=qARinNb9NtE Electronic supplementary material The online version of this article (10.1186/s12864-018-5101-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Natalia Polouliakh
- Sony Computer Science Laboratories Inc., 3-14-13 Higashigotanda, Shinagawa-ku, Tokyo, 141-0022, Japan. .,Department of Ophthalmology and Visual Sciences, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama City, Yokohama, 236-0004, Japan. .,Systems Biology Institute, 5-6-9 Shirokanedai, Minato-ku, Tokyo, 108-0071, Japan.
| | - Paul Horton
- AIST, Artificial Intelligence Research Center, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Kazuhiro Shibanai
- Department of Computer Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8552, Japan
| | - Kodai Takata
- Department of Computer Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8552, Japan
| | - Vanessa Ludwig
- Department of Biology, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich, Switzerland
| | - Samik Ghosh
- Systems Biology Institute, 5-6-9 Shirokanedai, Minato-ku, Tokyo, 108-0071, Japan
| | - Hiroaki Kitano
- Sony Computer Science Laboratories Inc., 3-14-13 Higashigotanda, Shinagawa-ku, Tokyo, 141-0022, Japan.,Systems Biology Institute, 5-6-9 Shirokanedai, Minato-ku, Tokyo, 108-0071, Japan
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6
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Multiple Inhibitory Factors Act in the Late Phase of HIV-1 Replication: a Systematic Review of the Literature. Microbiol Mol Biol Rev 2018; 82:82/1/e00051-17. [PMID: 29321222 DOI: 10.1128/mmbr.00051-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The use of lentiviral vectors for therapeutic purposes has shown promising results in clinical trials. The ability to produce a clinical-grade vector at high yields remains a critical issue. One possible obstacle could be cellular factors known to inhibit human immunodeficiency virus (HIV). To date, five HIV restriction factors have been identified, although it is likely that more factors are involved in the complex HIV-cell interaction. Inhibitory factors that have an adverse effect but do not abolish virus production are much less well described. Therefore, a gap exists in the knowledge of inhibitory factors acting late in the HIV life cycle (from transcription to infection of a new cell), which are relevant to the lentiviral vector production process. The objective was to review the HIV literature to identify cellular factors previously implicated as inhibitors of the late stages of lentivirus production. A search for publications was conducted on MEDLINE via the PubMed interface, using the keyword sequence "HIV restriction factor" or "HIV restriction" or "inhibit HIV" or "repress HIV" or "restrict HIV" or "suppress HIV" or "block HIV," with a publication date up to 31 December 2016. Cited papers from the identified records were investigated, and additional database searches were performed. A total of 260 candidate inhibitory factors were identified. These factors have been identified in the literature as having a negative impact on HIV replication. This study identified hundreds of candidate inhibitory factors for which the impact of modulating their expression in lentiviral vector production could be beneficial.
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7
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Abstract
In this chapter, we present an approach that allows a causal analysis of multiple "-omics" data with the help of an "upstream analysis" strategy. The goal of this approach is to identify master regulators in gene regulatory networks as potential drug targets for a pathological process. The data analysis strategy includes a state-of-the-art promoter analysis for potential transcription factor (TF)-binding sites using the TRANSFAC® database combined with an analysis of the upstream signal transduction pathways that control the activity of these TFs. When applied to genes that are associated with a switch to a pathological process, the approach identifies potential key molecules (master regulators) that may exert major control over and maintenance of transient stability of the pathological state. We demonstrate this approach on examples of analysis of multi-omics data sets that contain transcriptomics and epigenomics data in cancer. The results of this analysis helped us to better understand the molecular mechanisms of cancer development and cancer drug resistance. Such an approach promises to be very effective for rapid and accurate identification of cancer drug targets with true potential. The upstream analysis approach is implemented as an automatic workflow in the geneXplain platform ( www.genexplain.com ) using the open-source BioUML framework ( www.biouml.org ).
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Affiliation(s)
- Alexander E Kel
- Institute of Chemical Biology and Fundamental Medicine, SBRAN, Novosibirsk, Russia. .,Biosoft.ru, Ltd., Novosibirsk, Russia. .,geneXplain GmbH, Am Exer 10B, D-38302, Wolfenbüttel, Germany.
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8
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Wang J, Yang J, Yang Z, Lu X, Jin C, Cheng L, Wu N. RbAp48, a novel inhibitory factor that regulates the transcription of human immunodeficiency virus type 1. Int J Mol Med 2016; 38:267-74. [PMID: 27222146 DOI: 10.3892/ijmm.2016.2598] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 05/10/2016] [Indexed: 11/06/2022] Open
Abstract
Retinoblastoma binding protein 4 (RbAp48) is a histone chaperone which has been suggested to play a role in gene silencing. However, the role of RbAp48 in human immunodeficiency virus type 1 (HIV-1) infection and gene replication has not been determined to date, to the best of our knowledge. For this purpose, we demonstrated in the present study that RbAp48 expression was upregulated by HIV-1 infection, whereas the knockdown of RbAp48 promoted HIV infection and the production of virus particles. The ectopic expression of RbAp48 inhibited HIV-1 expression, and this inhibition correlated with a marked decrease in the expression of HIV-1 genomic RNA and various RNA transcripts. Further experiments to determine the mechanism responsible for the inhibitory effects of RbAp48 revealed that the ectopic expression of RbAp48 repressed HIV-1 long terminal repeat (LTR)-mediated basal transcription as well as TNF-α- and phorbol 12-myristate 13-acetate (PMA)‑activated transcription. Furthermore, the results of the electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) analysis revealed that RbAp48 binds to the HIV-1 LTR in vitro. Taken together, these findings demonstrate that, as a transcriptional cofactor, RbAp48 is likely to act as a potent antiretroviral defense.
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Affiliation(s)
- Juan Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
| | - Jin Yang
- Department of Medicine, Blood Center of Zhejiang Province, Hangzhou, Zhejiang 330100, P.R. China
| | - Zongxing Yang
- Xixi Hospital of Hangzhou, Hangzhou, Zhejiang 310023, P.R. China
| | - Xiangyun Lu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
| | - Changzhong Jin
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
| | - Linfang Cheng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
| | - Nanping Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
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9
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Ankers JM, Awais R, Jones NA, Boyd J, Ryan S, Adamson AD, Harper CV, Bridge L, Spiller DG, Jackson DA, Paszek P, Sée V, White MR. Dynamic NF-κB and E2F interactions control the priority and timing of inflammatory signalling and cell proliferation. eLife 2016; 5. [PMID: 27185527 PMCID: PMC4869934 DOI: 10.7554/elife.10473] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 04/13/2016] [Indexed: 01/07/2023] Open
Abstract
Dynamic cellular systems reprogram gene expression to ensure appropriate cellular fate responses to specific extracellular cues. Here we demonstrate that the dynamics of Nuclear Factor kappa B (NF-κB) signalling and the cell cycle are prioritised differently depending on the timing of an inflammatory signal. Using iterative experimental and computational analyses, we show physical and functional interactions between NF-κB and the E2 Factor 1 (E2F-1) and E2 Factor 4 (E2F-4) cell cycle regulators. These interactions modulate the NF-κB response. In S-phase, the NF-κB response was delayed or repressed, while cell cycle progression was unimpeded. By contrast, activation of NF-κB at the G1/S boundary resulted in a longer cell cycle and more synchronous initial NF-κB responses between cells. These data identify new mechanisms by which the cellular response to stress is differentially controlled at different stages of the cell cycle. DOI:http://dx.doi.org/10.7554/eLife.10473.001 Investigating how cells adapt to the constantly changing environment inside the body is vitally important for understanding how the body responds to an injury or infection. One of the ways in which human cells adapt is by dividing to produce new cells. This takes place in a repeating pattern of events, known as the cell cycle, through which a cell copies its DNA (in a stage known as S-phase) and then divides to make two daughter cells. Each stage of the cell cycle is tightly controlled; for example, a family of proteins called E2 factors control the entry of the cell into S phase. “Inflammatory” signals produced by a wound or during an infection can activate a protein called Nuclear Factor-kappaB (NF-κB), which controls the activity of genes that allow cells to adapt to the situation. Research shows that the activity of NF-κB is also regulated by the cell cycle, but it has not been clear how this works. Here, Ankers et al. investigated whether the stage of the cell cycle might affect how NF-κB responds to inflammatory signals. The experiments show that the NF-κB response was stronger in cells that were just about to enter S-phase than in cells that were already copying their DNA. An E2 factor called E2F-1 –which accumulates in the run up to S-phase – interacts with NF-κB and can alter the activity of certain genes. However, during S-phase, another E2 factor family member called E2F-4 binds to NF-κB and represses its activation. Next, Ankers et al. used a mathematical model to understand how these protein interactions can affect the response of cells to inflammatory signals. These findings suggest that direct interactions between E2 factor proteins and NF-κB enable cells to decide whether to divide or react in different ways to inflammatory signals. The research tools developed in this study, combined with other new experimental techniques, will allow researchers to accurately predict how cells will respond to inflammatory signals at different points in the cell cycle. DOI:http://dx.doi.org/10.7554/eLife.10473.002
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Affiliation(s)
- John M Ankers
- Centre for Cell Imaging, Institute of Integrative Biology, Liverpool, United Kingdom
| | - Raheela Awais
- Centre for Cell Imaging, Institute of Integrative Biology, Liverpool, United Kingdom.,Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - Nicholas A Jones
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - James Boyd
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - Sheila Ryan
- Centre for Cell Imaging, Institute of Integrative Biology, Liverpool, United Kingdom.,Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - Antony D Adamson
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - Claire V Harper
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - Lloyd Bridge
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom.,Department of Mathematics, University of Swansea, Swansea, United Kingdom
| | - David G Spiller
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - Dean A Jackson
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - Pawel Paszek
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
| | - Violaine Sée
- Centre for Cell Imaging, Institute of Integrative Biology, Liverpool, United Kingdom
| | - Michael Rh White
- Systems Microscopy Centre, Faculty of Life Sciences, Manchester, United Kingdom
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10
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Ertosun MG, Hapil FZ, Osman Nidai O. E2F1 transcription factor and its impact on growth factor and cytokine signaling. Cytokine Growth Factor Rev 2016; 31:17-25. [PMID: 26947516 DOI: 10.1016/j.cytogfr.2016.02.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 02/27/2016] [Indexed: 12/13/2022]
Abstract
E2F1 is a transcription factor involved in cell cycle regulation and apoptosis. The transactivation capacity of E2F1 is regulated by pRb. In its hypophosphorylated form, pRb binds and inactivates DNA binding and transactivating functions of E2F1. The growth factor stimulation of cells leads to activation of CDKs (cyclin dependent kinases), which in turn phosphorylate Rb and hyperphosphorylated Rb is released from E2F1 or E2F1/DP complex, and free E2F1 can induce transcription of several genes involved in cell cycle entry, induction or inhibition of apoptosis. Thus, growth factors and cytokines generally utilize E2F1 to direct cells to either fate. Furthermore, E2F1 regulates expressions of various cytokines and growth factor receptors, establishing positive or negative feedback mechanisms. This review focuses on the relationship between E2F1 transcription factor and cytokines (IL-1, IL-2, IL-3, IL-6, TGF-beta, G-CSF, LIF), growth factors (EGF, KGF, VEGF, IGF, FGF, PDGF, HGF, NGF), and interferons (IFN-α, IFN-β and IFN-γ).
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Affiliation(s)
- Mustafa Gokhan Ertosun
- Akdeniz University, Faculty of Medicine, Department of Medical Biology and Genetic, Kampus, Antalya 07070, Turkey
| | - Fatma Zehra Hapil
- Akdeniz University, Faculty of Medicine, Department of Medical Biology and Genetic, Kampus, Antalya 07070, Turkey
| | - Ozes Osman Nidai
- Akdeniz University, Faculty of Medicine, Department of Medical Biology and Genetic, Kampus, Antalya 07070, Turkey.
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11
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Hagenbuchner J, Ausserlechner MJ. Targeting transcription factors by small compounds--Current strategies and future implications. Biochem Pharmacol 2015; 107:1-13. [PMID: 26686579 DOI: 10.1016/j.bcp.2015.12.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 12/08/2015] [Indexed: 12/16/2022]
Abstract
Transcription factors are central regulators of gene expression and critically steer development, differentiation and death. Except for ligand-activated nuclear receptors, direct modulation of transcription factor function by small molecules is still widely regarded as "impossible". This "un-druggability" of non-ligand transcription factors is due to the fact that the interacting surface between transcription factor and DNA is huge and subject to significant changes during DNA-binding. Besides some "success studies" with compounds that directly interfere with DNA binding, drug targeting approaches mostly address protein-protein interfaces with essential co-factors, transcription factor dimerization partners, chaperone proteins or proteins that regulate subcellular shuttling. An alternative strategy represent DNA-intercalating, alkylating or DNA-groove-binding compounds that either block transcription factor-binding or change the 3D-conformation of the consensus DNA-strand. Recently, much interest has been focused on chromatin reader proteins that steer the recruitment and activity of transcription factors to a gene transcription start site. Several small compounds demonstrate that these epigenetic reader proteins are exciting new drug targets for inhibiting lineage-specific transcription in cancer therapy. In this research update we will discuss recent advances in targeting transcription factors with small compounds, the challenges that are related to the complex function and regulation of these proteins and also the possible future directions and applications of transcription factor drug targeting.
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Affiliation(s)
- Judith Hagenbuchner
- Department of Pediatrics II, Medical University Innsbruck, Innrain 66, A-6020 Innsbruck, Austria
| | - Michael J Ausserlechner
- Department of Pediatrics I, Medical University Innsbruck, Innrain 66, A-6020 Innsbruck, Austria.
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12
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Beyond receptors and signaling: epigenetic factors in the regulation of innate immunity. Immunol Cell Biol 2015; 93:233-44. [PMID: 25559622 PMCID: PMC4885213 DOI: 10.1038/icb.2014.101] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 10/31/2014] [Indexed: 12/14/2022]
Abstract
The interaction of innate immune cells with pathogens leads to changes in gene expression that elicit our body's first line of defense against infection. Although signaling pathways and transcription factors have a central role, it is becoming increasingly clear that epigenetic factors, in the form of DNA or histone modifications, as well as noncoding RNAs, are critical for generating the necessary cell lineage as well as context‐specific gene expression in diverse innate immune cell types. Much of the epigenetic landscape is set during cellular differentiation; however, pathogens and other environmental triggers also induce changes in histone modifications that can either promote tolerance or ‘train’ innate immune cells for a more robust antigen‐independent secondary response. Here we review the important contribution of epigenetic factors to the initiation, maintenance and training of innate immune responses. In addition, we explore how pathogens have hijacked these mechanisms for their benefit and the potential of small molecules targeting chromatin machinery as a way to boost or subdue the innate immune response in disease. The March 2015 issue contains a Special Feature on the epigenetic mechanisms underlying health and disease. Epigenetic modifications to chromatin influence the transcriptional status of our genes. Thus, understanding the epigenetic mechanisms that regulate immune cell fate are of great importance as they will provide insight into not only how to boost immune responses but also alter harmful ones such as autoimmunity and cancer. Immunology and Cell Biology thanks the coordinators of this Special Feature ‐ Rhys Allan ‐ for his planning and input.
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13
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Abstract
Lysine acetylation is a key mechanism that regulates chromatin structure; aberrant acetylation levels have been linked to the development of several diseases. Acetyl-lysine modifications create docking sites for bromodomains, which are small interaction modules found on diverse proteins, some of which have a key role in the acetylation-dependent assembly of transcriptional regulator complexes. These complexes can then initiate transcriptional programmes that result in phenotypic changes. The recent discovery of potent and highly specific inhibitors for the BET (bromodomain and extra-terminal) family of bromodomains has stimulated intensive research activity in diverse therapeutic areas, particularly in oncology, where BET proteins regulate the expression of key oncogenes and anti-apoptotic proteins. In addition, targeting BET bromodomains could hold potential for the treatment of inflammation and viral infection. Here, we highlight recent progress in the development of bromodomain inhibitors, and their potential applications in drug discovery.
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14
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Mbonye U, Karn J. Transcriptional control of HIV latency: cellular signaling pathways, epigenetics, happenstance and the hope for a cure. Virology 2014; 454-455:328-39. [PMID: 24565118 DOI: 10.1016/j.virol.2014.02.008] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 01/23/2014] [Accepted: 02/07/2014] [Indexed: 02/06/2023]
Abstract
Replication-competent latent HIV-1 proviruses that persist in the genomes of a very small subset of resting memory T cells in infected individuals under life-long antiretroviral therapy present a major barrier towards viral eradication. Multiple molecular mechanisms are required to repress the viral trans-activating factor Tat and disrupt the regulatory Tat feedback circuit leading to the establishment of the latent viral reservoir. In particular, latency is due to a combination of transcriptional silencing of proviruses via host epigenetic mechanisms and restrictions on the expression of P-TEFb, an essential co-factor for Tat. Induction of latent proviruses in the presence of antiretroviral therapy is expected to enable clearance of latently infected cells by viral cytopathic effects and host antiviral immune responses. An in-depth comprehensive understanding of the molecular control of HIV-1 transcription should inform the development of optimal combinatorial reactivation strategies that are intended to purge the latent viral reservoir.
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Affiliation(s)
- Uri Mbonye
- Department of Molecular Biology and Microbiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, United States
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, United States.
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15
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Wang J, Lv H, Xu L, Yang J, Yang Z, Wu N. Generation of Human Immunodeficiency Virus–1 Long Terminal Repeat Reporter Genes by Rapid Polymerase Chain Reaction–Mediated Mutagenesis. Lab Med 2013. [DOI: 10.1309/lmb66mq8jixdccqj] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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16
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Affiliation(s)
- Jonathan Karn
- Department of Molecular Biology and Microbiology, Case School of Medicine, Cleveland, OH, USA.
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17
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Su LH, Pan YJ, Huang YC, Cho CC, Chen CW, Huang SW, Chuang SF, Sun CH. A novel E2F-like protein involved in transcriptional activation of cyst wall protein genes in Giardia lamblia. J Biol Chem 2011; 286:34101-20. [PMID: 21835923 PMCID: PMC3190776 DOI: 10.1074/jbc.m111.280206] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 08/09/2011] [Indexed: 01/01/2023] Open
Abstract
Giardia lamblia differentiates into resistant walled cysts for survival outside the host and transmission. During encystation, synthesis of cyst wall proteins is coordinately induced. The E2F family of transcription factors in higher eukaryotes is involved in cell cycle progression and cell differentiation. We asked whether Giardia has E2F-like genes and whether they influence gene expression during Giardia encystation. Blast searches of the Giardia genome database identified one gene (e2f1) encoding a putative E2F protein with two putative DNA-binding domains. We found that the e2f1 gene expression levels increased significantly during encystation. Epitope-tagged E2F1 was found to localize to nuclei. Recombinant E2F1 specifically bound to the thymidine kinase and cwp1-3 gene promoters. E2F1 contains several key residues for DNA binding, and mutation analysis revealed that its binding sequence is similar to those of the known E2F family proteins. The E2F1-binding sequences were positive cis-acting elements of the thymidine kinase and cwp1 promoters. We also found that E2F1 transactivated the thymidine kinase and cwp1 promoters through its binding sequences in vivo. Interestingly, E2F1 overexpression resulted in a significant increase of the levels of CWP1 protein, cwp1-3 gene mRNA, and cyst formation. We also found E2F1 can interact with Myb2, a transcription factor that coordinate up-regulates the cwp1-3 genes during encystation. Our results suggest that E2F family has been conserved during evolution and that E2F1 is an important transcription factor in regulation of the Giardia cwp genes, which are key to Giardia differentiation into cysts.
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Affiliation(s)
- Li-Hsin Su
- From the Department of Parasitology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Yu-Jiao Pan
- From the Department of Parasitology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Yu-Chang Huang
- From the Department of Parasitology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chao-Cheng Cho
- From the Department of Parasitology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chia-Wei Chen
- From the Department of Parasitology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Shao-Wei Huang
- From the Department of Parasitology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Sheng-Fung Chuang
- From the Department of Parasitology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chin-Hung Sun
- From the Department of Parasitology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
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18
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Kamčeva T, Flemmig J, Damnjanović B, Arnhold J, Mijatović A, Petković M. Inhibitory effect of platinum and ruthenium bipyridyl complexes on porcine pancreatic phospholipase A2. Metallomics 2011; 3:1056-63. [PMID: 21909579 DOI: 10.1039/c1mt00088h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Pancreatic phospholipase A(2) (PLA(2)) plays an important role in cellular homeostasis as well as in the process of carcinogenesis. Effects of metallo-drugs used as chemotherapeutics on the activity of this enzyme are unknown. In this work, the interaction between porcine pancreatic PLA(2) and two selected transition metal complexes--tetrachloro(bipyridine) platinum(IV) ([PtCl(4)(bipy)]) and dichloro (bipyridine) ruthenium(III)chloride ([RuCl(2)(bipy)(2)]Cl)--was studied. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and fluorescence spectroscopy have been used to analyse the enzyme activity in the absence and presence of metal complexes and to verify potential binding of these drugs to the enzyme. The tested metal complexes decreased the activity of phospholipase A(2) in an uncompetitive inhibition mode. A binding of the ruthenium complex near the active site of the enzyme could be evidenced and possible modes of interaction are discussed.
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Affiliation(s)
- Tina Kamčeva
- Laboratory of Physical Chemistry, Institute of Nuclear Sciences Vinča, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, Serbia.
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19
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Activation of NF-kB pathway by virus infection requires Rb expression. PLoS One 2009; 4:e6422. [PMID: 19649275 PMCID: PMC2713421 DOI: 10.1371/journal.pone.0006422] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 06/08/2009] [Indexed: 12/02/2022] Open
Abstract
The retinoblastoma protein Rb is a tumor suppressor involved in cell cycle control, differentiation, and inhibition of oncogenic transformation. Besides these roles, additional functions in the control of immune response have been suggested. In the present study we investigated the consequences of loss of Rb in viral infection. Here we show that virus replication is increased by the absence of Rb, and that Rb is required for the activation of the NF-kB pathway in response to virus infection. These results reveal a novel role for tumor suppressor Rb in viral infection surveillance and further extend the concept of a link between tumor suppressors and antiviral activity.
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20
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Jhou RS, Sun KH, Sun GH, Wang HH, Chang CI, Huang HC, Lu SY, Tang SJ. Inhibition of cyclin-dependent kinases by olomoucine and roscovitine reduces lipopolysaccharide-induced inflammatory responses via down-regulation of nuclear factor kappaB. Cell Prolif 2009; 42:141-9. [PMID: 19250292 DOI: 10.1111/j.1365-2184.2009.00584.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVES Initiation and maintenance of pro-inflammatory reactions elicited by bacterial lipopolysaccharide and/or cytokines in the macrophage lineage have been reported to play a crucial role in acute and chronic pathogenic effects. Whether pro-inflammatory responses triggered by lipopolysaccharide in growth arrested cells differ from those in proliferating cells remains unanswered. MATERIALS AND METHODS Olomoucine and roscovitine are cyclin-dependent kinase (CDK) inhibitors that prevent progression through the cell cycle. After treatment with CDK inhibitors, expression of pro-inflammatory genes was analysed by reverse transcriptase-polymerase chain reaction. Protein levels of inducible nitric oxide synthase (iNOS) and nuclear factor kappaB (NF-kappaB) were determined by Western blotting. Promoter activity of iNOS was measured by the luciferase activity assay. RESULTS In this study we have demonstrated that both olomoucine and roscovitine inhibit cell proliferation and diminish nitric oxide production and cytokine gene expression, in lipopolysaccharide-stimulated murine RAW264.7 macrophages. In addition, olomoucine reduces iNOS promoter activity and alleviates NF-kappaB transcription activation. After co-transfection with E2F1 interference RNA, suppression of lipopolysaccharide-mediated iNOS promoter activity and NF-kappaB activation was observed. Furthermore, we demonstrated that olomoucine-induced growth arrested cells reduce expression of the p65 subunit of NF-kappaB. CONCLUSIONS The findings of this study suggest that inhibition of cell-cycle progression is capable of reducing pro-inflammatory responses via down-regulation of NF-kappaB.
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Affiliation(s)
- R-S Jhou
- Section of Urology, Cheng-Hsin Rehabilitation Medical Center, Taipei, Taiwan
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21
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Tzang BS, Chiu CC, Tsai CC, Lee YJ, Lu IJ, Shi JY, Hsu TC. Effects of human parvovirus B19 VP1 unique region protein on macrophage responses. J Biomed Sci 2009; 16:13. [PMID: 19272185 PMCID: PMC2653524 DOI: 10.1186/1423-0127-16-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 01/24/2009] [Indexed: 12/14/2022] Open
Abstract
Background Activity of secreted phospholipase A (sPLA2) has been implicated in a wide range of cellular responses. However, little is known about the function of human parvovirus B19-VP1 unique region (VP1u) with sPLA2 activity on macrophage. Methods To investigate the roles of B19-VP1u in response to macrophage, phospholipase A2 activity, cell migration assay, phagocytosis activity, metalloproteinase assay, RT-PCR and immunoblotting were performed. Results In the present study, we report that migration, phagocytosis, IL-6, IL-1β mRNA, and MMP9 activity are significantly increased in RAW264.7 cells by B19-VP1u protein with sPLA2 activity, but not by B19-VP1uD175A protein that is mutated and lacks sPLA2 activity. Additionally, significant increases of phosphorylated ERK1/2 and JNK proteins were detected in macrophages that were treated with B19-VP1u protein, but not when they were treated with B19-VP1uD175A protein. Conclusion Taken together, our experimental results suggest that B19-VP1u with sPLA2 activity affects production of IL-6, IL-1β mRNA, and MMP9 activity, possibly through the involvement of ERK1/2 and JNK signaling pathways. These findings could provide clues in understanding the role of B19-VP1u and its sPLA2 enzymatic activity in B19 infection and B19-related diseases.
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Affiliation(s)
- Bor-Show Tzang
- Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung, Taiwan.
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22
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Lim CA, Yao F, Wong JJY, George J, Xu H, Chiu KP, Sung WK, Lipovich L, Vega VB, Chen J, Shahab A, Zhao XD, Hibberd M, Wei CL, Lim B, Ng HH, Ruan Y, Chin KC. Genome-wide mapping of RELA(p65) binding identifies E2F1 as a transcriptional activator recruited by NF-kappaB upon TLR4 activation. Mol Cell 2007; 27:622-35. [PMID: 17707233 DOI: 10.1016/j.molcel.2007.06.038] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 05/04/2007] [Accepted: 06/25/2007] [Indexed: 12/18/2022]
Abstract
NF-kappaB is a key mediator of inflammation. Here, we mapped the genome-wide loci bound by the RELA subunit of NF-kappaB in lipopolysaccharide (LPS)-stimulated human monocytic cells, and together with global gene expression profiling, found an overrepresentation of the E2F1-binding motif among RELA-bound loci associated with NF-kappaB target genes. Knockdown of endogenous E2F1 impaired the LPS inducibility of the proinflammatory cytokines CCL3(MIP-1alpha), IL23A(p19), TNF-alpha, and IL1-beta. Upon LPS stimulation, E2F1 is rapidly recruited to the promoters of these genes along with p50/RELA heterodimer via a mechanism that is dependent on NF-kappaB activation. Together with the observation that E2F1 physically interacts with p50/RELA in LPS-stimulated cells, our findings suggest that NF-kappaB recruits E2F1 to fully activate the transcription of NF-kappaB target genes. Global gene expression profiling subsequently revealed a spectrum of NF-kappaB target genes that are positively regulated by E2F1, further demonstrating the critical role of E2F1 in the Toll-like receptor 4 pathway.
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Affiliation(s)
- Ching-Aeng Lim
- Laboratory of Immunology and Virology, Genome Institute of Singapore, 138672 Singapore
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23
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Darnell GA, Schroder WA, Gardner J, Harrich D, Yu H, Medcalf RL, Warrilow D, Antalis TM, Sonza S, Suhrbier A. SerpinB2 Is an Inducible Host Factor Involved in Enhancing HIV-1 Transcription and Replication. J Biol Chem 2006. [DOI: 10.1016/s0021-9258(19)84047-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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24
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Darnell GA, Schroder WA, Gardner J, Harrich D, Yu H, Medcalf RL, Warrilow D, Antalis TM, Sonza S, Suhrbier A. SerpinB2 Is an Inducible Host Factor Involved in Enhancing HIV-1 Transcription and Replication. J Biol Chem 2006; 281:31348-58. [PMID: 16923810 DOI: 10.1074/jbc.m604220200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serine protease inhibitor SerpinB2 (plasminogen activator inhibitor-2) is a major product of activated monocytes and macrophages and is substantially induced during most inflammatory processes. Distinct from its widely described extracellular role as an inhibitor of urokinase plasminogen activator, SerpinB2 has recently been shown to have an intracellular role as a retinoblastoma protein (Rb)-binding protein that inhibits Rb degradation. Here we show that HIV-1 infection and gp120 treatment of human peripheral blood mononuclear cells resulted in induction of SerpinB2. Furthermore, SerpinB2 expression in THP-1 monocyte/macrophage, Jurkat T, and HeLa cell lines increased replication of HIV-1 and enhanced transcription from the HIV-1 long terminal repeat (LTR) promoter by 3-10-fold. Increased HIV-1 gene expression and transcription was also observed in activated macrophages from SerpinB2+/+ mice compared with macrophages from SerpinB2-/- mice. The SerpinB2-mediated elevation of Rb protein levels appeared to be responsible for enhancing transcription from the core promoter region of the LTR by relieving HDM2-mediated inhibition of Sp1 and/or by increasing the Sp1/Sp3 expression ratios. This is the first report associating HIV-1 replication with SerpinB2 expression and illustrates that SerpinB2 is a potentially important inducible host factor that significantly promotes HIV-1 replication.
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Affiliation(s)
- Grant A Darnell
- Queensland Institute of Medical Research, Brisbane, Queensland 4029, Australia
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25
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Marwaha V, Chen YH, Helms E, Arad S, Inoue H, Bord E, Kishore R, Sarkissian RD, Gilchrest BA, Goukassian DA. T-oligo treatment decreases constitutive and UVB-induced COX-2 levels through p53- and NFkappaB-dependent repression of the COX-2 promoter. J Biol Chem 2005; 280:32379-88. [PMID: 16046401 DOI: 10.1074/jbc.m503245200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chronically irradiated murine skin and UV light-induced squamous cell carcinomas overexpress the inducible isoform of cyclooxygenase (COX-2), and COX-2 inhibition reduces photocarcinogenesis in mice. We have reported previously that DNA oligonucleotides substantially homologous to the telomere 3'-overhang (T-oligos) induce DNA repair capacity and multiple other cancer prevention responses, in part through up-regulation and activation of p53. To determine whether T-oligos affect COX-2 expression, human newborn keratinocytes and fibroblasts were pretreated with T-oligos or diluent alone for 24 h, UV-irradiated, and processed for Western blotting. In both cell types, T-oligos transcriptionally down-regulated base-line and UV light-induced COX-2 expression, coincident with p53 activation. In fibroblasts with wild type versus dominant negative p53 (p53(WT) versus p53(DN)), T-oligos decreased constitutive expression of a COX-2 reporter plasmid by >50%. We then examined NFkappaB, a known positive regulator of COX-2 transcription. In p53(WT) but not in p53(DN) fibroblasts and in human keratinocytes, T-oligos decreased readout of an NFkappaB promoter-driven reporter plasmid and decreased NFkappaB binding to DNA. After T-oligo treatment and subsequent UV irradiation, binding of the transcriptional co-activator protein p300 to NFkappaB was decreased, whereas binding of p300 to p53 was increased. Human skin explants provided with T-oligos had markedly decreased COX-2 immunostaining both at base-line and post-UV light, coincident with increased p53 immunostaining. We conclude that T-oligos transcriptionally down-regulate COX-2 expression in human skin via activation and up-regulation of p53, at least in part by inhibiting NFkappaB transcriptional activation. Decreased COX-2 expression may contribute to the observed ability of T-oligos to reduce photocarcinogenesis.
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Affiliation(s)
- Vaneeta Marwaha
- Department of Dermatology, Boston University School of Medicine, Massachusetts 02118, USA
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26
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De Falco G, Bellan C, Lazzi S, Claudio P, La Sala D, Cinti C, Tosi P, Giordano A, Leoncini L. Interaction between HIV-1 Tat and pRb2/p130: a possible mechanism in the pathogenesis of AIDS-related neoplasms. Oncogene 2003; 22:6214-9. [PMID: 13679860 DOI: 10.1038/sj.onc.1206637] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tat protein is an early nonstructural protein necessary for virus replication, which is secreted by infected cells and taken up by uninfected cells. Extensive evidence indicates that Tat may be a cofactor in the development of AIDS-related neoplasms. The molecular mechanism underlying Tat's oncogenic activity may include deregulation of cellular genes. Among these genes, it has recently been shown that pRb2/p130 oncosuppressor protein is one of the targets in the interaction between HIV gene product Tat and host proteins. However, whether the HIV-1 gene product Tat may inactivate the oncosuppressive function of pRb2/p130 has not yet been elucidated. Here, we show that mRNA levels of pRb2/p130 increase in the presence of Tat, whereas no change in the phosphorylation status of pRb2/p130 is observed. In addition, Tat can inhibit the growth control activity exerted by pRb2/p130 in the T98G cell line. Finally, Tat does not compete with E2F-4 in binding to pRb2/p130. The interaction between Tat and pRb2/p130 seems to result in the deregulation of the control exerted by pRb2/p130 on the cell cycle. Taken together, these results open a window on the role of pRb2/p130 in AIDS-related oncogenesis.
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Affiliation(s)
- Giulia De Falco
- Department of Human Pathology and Oncology, University of Siena, Siena, Italy
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27
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Abstract
Since the emergence of the HIV pandemic, a close association between HIV infection and the development of a selected group of cancers has been acknowledged. The introduction of highly active antiretroviral therapy, however, has had a dramatic impact on the incidences of several AIDS-defining malignancies. This suggests the possibility of a direct and indirect role of HIV in HIV-related tumor genesis. The aim of this paper is to review the pathology of AIDS-related malignancies, taking into account the pathogenetic mechanisms and their potential for improving the treatment of these tumors.
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Affiliation(s)
- C Bellan
- Department of Human Pathology and Oncology, University of Siena, Siena, Italy
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28
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Goukassian DA, Kishore R, Krasinski K, Dolan C, Luedemann C, Yoon YS, Kearney M, Hanley A, Ma H, Asahara T, Isner JM, Losordo DW. Engineering the response to vascular injury: divergent effects of deregulated E2F1 expression on vascular smooth muscle cells and endothelial cells result in endothelial recovery and inhibition of neointimal growth. Circ Res 2003; 93:162-9. [PMID: 12829616 DOI: 10.1161/01.res.0000082980.94211.3a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) is expressed locally in the vessel wall after angioplasty and induces growth arrest and apoptosis in endothelial cells (ECs), thereby delaying reendothelialization. Prior studies have shown that direct antagonism of TNF-alpha, using a systemically administered soluble receptor, can enhance endothelial recovery and reduce neointimal thickening. These studies have also shown that downregulation of the transcription factor E2F1 was a key mechanism of TNF's effect on ECs. We now show that Ad-E2F1 overexpression at sites of balloon injury accelerates functional endothelial recovery, consistent with the prior in vitro findings. Moreover these studies also reveal divergent effects of TNF-alpha and overexpression of E2F1 on ECs versus VSMCs. TNF-alpha exposure of VSMCs had no affect on proliferation or apoptosis, in contrast to the effect seen in ECs. In Ad-E2F1-transduced VSMCs, however, TNF-alpha-induced marked apoptosis in contrast to the survival effect seen in ECs. Finally, these studies suggest that differential activation of NF-kappaB may play a key role in mediating these opposing effects. Nuclear translocation and transcriptional activity of NF-kappaB was markedly attenuated in Ad-E2F1-transduced VSMCs, whereas it remained active in similarly treated ECs when the cells were exposed to TNF-alpha. These studies reveal that overexpression of Ad-E2F1 primes VSMCs to TNF-alpha-induced apoptosis. Furthermore, E2F1 potentiates VSMC death by blocking antiapoptotic signaling pathway through inhibition of NF-kappaB activation. The divergent responses of VSMCs and ECs to E2F1 overexpression provide unique therapeutic possibilities: simultaneously targeting the cell cycle of two different cell types, within same tissue microenvironment resulting in opposite and biologically complimentary effects.
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MESH Headings
- Active Transport, Cell Nucleus
- Animals
- Apoptosis
- Carotid Artery Injuries/metabolism
- Carotid Artery Injuries/pathology
- Caspases/metabolism
- Cattle
- Cell Cycle Proteins
- Cell Division/drug effects
- Cell Division/genetics
- Cells, Cultured
- DNA-Binding Proteins
- Disease Models, Animal
- E2F Transcription Factors
- E2F1 Transcription Factor
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Gene Expression Regulation
- Genes, Reporter
- Humans
- Hyperplasia/pathology
- I-kappa B Proteins/metabolism
- Mice
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- NF-KappaB Inhibitor alpha
- NF-kappa B/genetics
- NF-kappa B/metabolism
- Rats
- Rats, Sprague-Dawley
- Recovery of Function
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transfection
- Tumor Necrosis Factor-alpha/pharmacology
- Tunica Intima/growth & development
- Tunica Intima/injuries
- Tunica Intima/pathology
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Affiliation(s)
- David A Goukassian
- Department of Medicine, Division of Cardiovascular Research, St Elizabeth's Medical Center, Boston, Mass, USA
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29
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Tanaka J, Ishida T, Choi BI, Yasuda J, Watanabe T, Iwakura Y. Latent HIV-1 reactivation in transgenic mice requires cell cycle -dependent demethylation of CREB/ATF sites in the LTR. AIDS 2003; 17:167-75. [PMID: 12545075 DOI: 10.1097/00002030-200301240-00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We previously produced a line of transgenic mice that carried the HIV-1 genome deficient in the gene. Although the HIV-1 genome in the lymphocytes was dormant under normal physiological conditions, it could be reactivated by lipopolysaccharide (LPS) administration via induction of interleukin-1alpha/beta and tumour necrosis factor-alpha. In this report, we analysed further the reactivation mechanism of the latent HIV-1 using this transgenic mouse model. DESIGN and methods: Possible involvement of CpG methylation in HIV-1 latency was examined by treating transgenic lymphocytes with a demethylating agent, 5'-azacytidine. CpG methylation in the HIV-1 long terminal repeat (LTR) was analysed using the bisulfite genomic sequencing method. As previous studies suggested that CpG demethylation depended on the cell cycle progression, we analysed the relation between cell cycle progression and LPS-induced reactivation of HIV-1 by labelling lymphocytes with an intracellular fluorescein, carboxyfluorescein diacetate succinimidyl ester. RESULTS We found that 5'-azacytidine enhanced HIV-1 expression ninefold compared to treatment with LPS alone. Furthermore, HIV-1 p24 induction by LPS was observed only in cells that had undergone cell division, while induction was prevented in cells in which cell cycle progression was blocked either by mimosine, aphidicolin, or nocodazole. LPS-induced HIV-1 reactivation was associated with demethylation of two CpG sites located in the CREB/ATF binding sites in the HIV-1 LTR in a cell cycle-dependent manner. CONCLUSIONS These observations indicate that cell cycle progression-dependent demethylation of the CREB/ATF sites in the LTR is crucial for the reactivation of latent HIV-1 genome in transgenic mice.
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Affiliation(s)
- J Tanaka
- Center for Experimental Medicine and the Department of Cancer Research, Institute of Medical Science, University of Tokyo, Japan
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Ambrosino C, Palmieri C, Puca A, Trimboli F, Schiavone M, Olimpico F, Ruocco MR, di Leva F, Toriello M, Quinto I, Venuta S, Scala G. Physical and functional interaction of HIV-1 Tat with E2F-4, a transcriptional regulator of mammalian cell cycle. J Biol Chem 2002; 277:31448-58. [PMID: 12055184 DOI: 10.1074/jbc.m112398200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tat protein of the human immunodeficiency virus type-1 (HIV-1) plays a critical role in the regulation of viral transcription and replication. In addition, Tat regulates the expression of a variety of cellular genes and could account for AIDS-associated diseases including Kaposi's Sarcoma and non-Hodgkin's lymphoma by interfering with cellular processes such as proliferation, differentiation, and apoptosis. The molecular mechanisms underlying the pleiotropic activities of Tat may include the generation of functional heterodimers of Tat with cellular proteins. By screening a human B-lymphoblastoid cDNA library in the yeast two-hybrid system, we identified E2F-4, a member of E2F family of transcription factors, as a Tat-binding protein. The interaction between Tat and E2F-4 was confirmed by GST pull-down experiments performed with cellular extracts as well as with in vitro translated E2F-4. The physical association of Tat and E2F-4 was confirmed by in vivo binding experiments where Tat.E2F-4 heterodimers were recovered from Jurkat cells by immunoprecipitation and immunoblotting. By using plasmids expressing mutant forms of Tat and E2F-4, the domains involved in Tat.E2F-4 interaction were identified as the regions encompassing amino acids 1-49 of Tat and amino acids 1-184 of E2F-4. Tat x E2F-4 complexes were shown to bind to E2F cis-regions with increased efficiency compared with E2F-4 alone and to mediate the activity of E2F-dependent promoters including HIV-1 long terminal repeat and cyclin A. The data point to Tat as an adaptor protein that recruits cellular factors such as E2F-4 to exert its multiple biological activities.
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Affiliation(s)
- Concetta Ambrosino
- Department of Clinical and Experimental Medicine, Medical School, University of Catanzaro, 88100 Catanzaro, Italy
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31
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Cook JL, Walker TA, Worthen GS, Radke JR. Role of the E1A Rb-binding domain in repression of the NF-kappa B-dependent defense against tumor necrosis factor-alpha. Proc Natl Acad Sci U S A 2002; 99:9966-71. [PMID: 12119420 PMCID: PMC126608 DOI: 10.1073/pnas.162082999] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The adenoviral E1A oncogene sensitizes mammalian cells to tumor necrosis factor-alpha (TNF-alpha), in part by repressing the nuclear factor-kappa B (NF-kappa B)-dependent defense against this cytokine. Other E1A activities involve binding to either p300/cyclic AMP response element-binding protein (CBP) or retinoblastoma (Rb)-family proteins, but the roles of E1A interactions with these transcriptional regulators in sensitizing cells to TNF-alpha are unclear. E1A expression did not block upstream events in TNF-alpha-induced activation of NF-kappa B in NIH 3T3 cells, including degradation of I kappa B-alpha, nuclear translocation of NF-kappa B subunits, and their dimeric binding to kappa B sequences in the nucleus. However, E1A markedly repressed NF-kappa B-dependent transcription and sensitized cells to TNF-alpha induced apoptosis. These E1A effects were selective for kappa B-dependent transcription and for the function of the NF-kappa B p65/RelA subunit. A four amino acid E1A deletion that eliminates binding to Rb-family proteins blocked both repression of TNF-alpha-induced transcription and sensitization to apoptosis. In contrast, mutations that eliminate E1A binding to p300/CBP (coactivators of p65/RelA) did not affect either E1A activity. These data suggest that E1A-Rb-binding blocks the NF-kappa B-dependent activation response to TNF-alpha by altering the function of p65/RelA at a stage after formation of the transcription factor-enhancer complex. These observations also open questions about the general role of Rb-family proteins in modulation of NF-kappa B-dependent transcription.
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Affiliation(s)
- James L Cook
- Department of Medicine and the Cancer Center, University of Illinois College of Medicine, MC-735, Chicago, IL 60612, USA.
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32
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Chen WM, Soria J, Soria C, Krimsky M, Yedgar S. Control of capillary formation by membrane-anchored extracellular inhibitor of phospholipase A(2). FEBS Lett 2002; 522:113-8. [PMID: 12095629 DOI: 10.1016/s0014-5793(02)02907-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Secretory phospholipase A(2) (sPLA(2)) has been reported to be involved in cell proliferation in general and in endothelial cell migration, processes required for capillary formation. Subsequently, we examined the potential control of angiogenesis by sPLA(2) inhibition, using a cell-impermeable sPLA(2) inhibitor composed of N-derivatized phosphatidyl-ethanolamine linked to hyaluronic acid. This inhibitor effectively inhibits the proliferation and migration of human bone marrow endothelial cells in a dose-dependent manner, and suppresses capillary formation induced by growth factors involved in vascularization of tumors and of atherosclerotic plaques. It is proposed that sPLA(2) inhibition introduces a novel approach in the control of cancer development and atherosclerosis.
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Affiliation(s)
- W M Chen
- INSERM - EMI 99-12, Hôtel Dieu, Paris, France
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33
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Lazzi S, Bellan C, De Falco G, Cinti C, Ferrari F, Nyongo A, Claudio PP, Tosi GM, Vatti R, Gloghini A, Carbone A, Giordano A, Leoncini L, Tosi P. Expression of RB2/p130 tumor-suppressor gene in AIDS-related non-Hodgkin's lymphomas: implications for disease pathogenesis. Hum Pathol 2002; 33:723-31. [PMID: 12196924 DOI: 10.1053/hupa.2002.125372] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this study we examined 21 cases of AIDS-related lymphomas for genomic organization and expression of RB2/p130 oncosuppressor gene and compared the results with the proliferative features of these neoplasms. We found no mutations in the RB2/p130 gene and unusually high percentages of cells expressing nuclear pRb2/p130 in tumors with a high proliferative activity, such as AIDS-related lymphomas. These findings might suggest that a molecular mechanism usually observed in viral-linked oncogenesis could be involved. We performed in vitro and in vivo binding assays to investigate whether the human immunodeficiency virus (HIV) gene product Tat and Rb2/p130 could interact. The results of these assays revealed that the HIV-1 Tat protein binds specifically to pRb2/p130. This may result in the inactivation of its oncosuppressive properties and the induction of genes needed to proceed through the cell cycle including p107, cyclin A, and cyclin B. Using single-cell polymerase chain reaction (PCR) assay, we found HIV-1 DNA in the neoplastic cells of only 2 of the 21 cases examined, whereas PCR on whole tissue revealed HIV-1 DNA in all of the cases. Furthermore, a diffuse and nuclear stain was observed in tissue sections with anti-Tat monoclonal antibody. These findings are in accordance with the notion that soluble Tat protein could function as a biologically active extracellular protein released by infected cells and taken up readily by uninfected B cells. In conclusion, our results seem to suggest that pRb2/p130 oncosuppressor protein may be a target in the interaction between the HIV-1 gene products and host proteins.
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MESH Headings
- Adult
- Cell Line
- Child, Preschool
- DNA Mutational Analysis
- DNA Primers/chemistry
- DNA, Neoplasm/analysis
- DNA, Viral/analysis
- Embryo, Mammalian
- Female
- Gene Expression Regulation, Viral
- Gene Products, tat/immunology
- Gene Products, tat/metabolism
- HIV-1/genetics
- HIV-1/metabolism
- Humans
- In Situ Hybridization
- Kidney
- Lymphoma, AIDS-Related/genetics
- Lymphoma, AIDS-Related/metabolism
- Lymphoma, AIDS-Related/pathology
- Male
- Middle Aged
- Phosphoproteins/genetics
- Phosphoproteins/metabolism
- Protein Binding
- Proteins
- Retinoblastoma-Like Protein p130
- Transfection
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Stefano Lazzi
- Institute of Pathological Anatomy and Histology, University of Siena, Siena, Italy
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Varela LM, Stangle-Castor NC, Shoemaker SF, Shea-Eaton WK, Ip MM. TNFalpha induces NFkappaB/p50 in association with the growth and morphogenesis of normal and transformed rat mammary epithelial cells. J Cell Physiol 2001; 188:120-31. [PMID: 11382928 DOI: 10.1002/jcp.1103] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In contrast to the cytotoxic or cytostatic effect of TNFalpha on many breast cancer cell lines, TNFalpha stimulates growth and morphogenesis of normal rat mammary epithelial cells (MEC). The present studies were carried out to determine whether there are intrinsic differences between normal and malignant MEC which may explain the differing responsiveness to TNFalpha. Freshly isolated rat MEC organoids from normal mammary gland or 1-methyl-1-nitrosourea-induced mammary tumors were treated with TNFalpha for 21 days. Unexpectedly, TNFalpha stimulated growth and morphogenesis of both normal and transformed MEC in primary culture, although in transformed cells its effects were delayed and the majority of the colonies were histologically abnormal, with multiple cell layers and no lumen. Since NFkappaB is a key mediator of TNFalpha action and has been implicated in carcinogenesis, the expression of the p50, p52, p65, and c-rel NFkappaB proteins in normal and transformed MEC was determined. Expression of p52 was significantly reduced in tumor cells, and p50 was absent, although its putative precursor, p105 was abundant. There were no changes in the levels of p65 or c-rel. TNFalpha induced a pronounced and sustained increase of a p50 homodimeric NFkappaB/DNA complex in both normal and transformed MEC. However, in transformed MEC, NFkappaB binding was initially undetectable but then increased in response to TNFalpha. Thus, NFkappaB expression and DNA binding activity are altered during mammary carcinogenesis. In addition, the significant increase in NFkappaB/p50 DNA-binding was temporally coincident with TNFalpha-induced growth and morphogenesis, suggesting that it may play a significant role in both normal development and carcinogenesis.
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Affiliation(s)
- L M Varela
- Department of Pharmacology and Therapeutics, Grace Cancer Drug Center, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
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35
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Ansari SA, Safak M, Del Valle L, Enam S, Amini S, Khalili K. Cell cycle regulation of NF-kappa b-binding activity in cells from human glioblastomas. Exp Cell Res 2001; 265:221-33. [PMID: 11302687 DOI: 10.1006/excr.2001.5168] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Glioblastoma multiforme is a highly malignant and anaplastic tumor of the central nervous system representing more than 50% of all malignant gliomas. The cell origin of this highly undifferentiated tumor remains obscure, although it is postulated that glioblastomas are developed from astrocytes. The rapid growth of the glioma and the state of its undifferentiation are attributed to the deregulation of several signal transduction pathways and cell cycle events. Recent studies showed diverse functions for the NF-kappa B/Rel family of inducible transcription factors including differentiation, apoptosis, oncogenesis, and cell cycle regulation. We sought to examine the level of NF-kappa B activity throughout the glioma's cell cycle. Results from band-shift studies indicated a biphasic NF-kappa B DNA-binding activity in the nuclei of cycling glioblastoma cells. We showed that NF-kappa B-binding activity maximizes in nuclear extracts at specific cell cycle stages including G0/G1, mid-late G1, and S phase. Results from Northern blotting studies revealed that the differential expression of the NF-kappa B subunits, p50 and p65, may not be responsible for cell cycle stage-specific association of NF-kappa B subunits with DNA. However, results from Western blotting analysis utilizing nuclear extracts from glioma cells throughout the cell cycle demonstrated that the nuclear accumulation of p50 and p65 perfectly correlates with their DNA-binding activity. These observations suggest that the nuclear translocation of the p50/p65 subunit of NF-kappa B in glioma cells is cell cycle stage-dependent and that is distinct from the differential mRNA expression of these genes during glioma cell cycling. The possible role of NF-kappa B in glioma cell formation and regulation of cellular genes by NF-kappa B in these tumor cells is discussed.
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Affiliation(s)
- S A Ansari
- Center for Neurovirology and Cancer Biology, College of Science and Technology, Temple University, 1900 North 12th Street, 015-96, Philadelphia, Pennsylvania 19122, USA
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36
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Mandal AK, Zhang Z, Chou JY, Zimonjic D, Keck CL, Popescu N, Mukherjee AB. Molecular characterization of murine pancreatic phospholipase A(2). DNA Cell Biol 2001; 20:149-57. [PMID: 11313018 DOI: 10.1089/104454901300068988] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The pancreatic secretory phospholipase A(2) (sPLA(2)IB) is considered to be a digestive enzyme, although it has several important receptor-mediated functions. In this study, using the newly isolated murine sPLA(2)IB cDNA clone as a probe, we demonstrate that in addition to the pancreas, the sPLA(2)IB mRNA was expressed in extrapancreatic organs such as the liver, spleen, duodenum, colon, and lungs. We also demonstrate that sPLA(2)IB mRNA expression was detectable from the 17(th) day of gestation in the developing mouse fetus, coinciding with the time of completion of differentiation of the pancreas. Furthermore, the mRNA expression pattern of sPLA(2)IB was distinct from those of sPLA(2)IIA and cPLA(2) in various tissues examined. The murine sPLA(2)IB gene structure is well conserved, consistent with findings in other mammalian species, and this gene mapped to the region of mouse chromosome 5F1-G1.1. Taken together, our results suggest that sPLA(2)IB plays important roles both in the pancreas and in extrapancreatic tissues and that in the mouse, its expression is developmentally regulated.
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Affiliation(s)
- A K Mandal
- Section on Developmental Genetics, Heritable Disorders Branch, The National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892, USA
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Machado J, Fernandez PC, Baumann I, Dobbelaere DA. Characterisation of NF-kappa B complexes in Theileria parva-transformedT cells. Microbes Infect 2000; 2:1311-20. [PMID: 11018447 DOI: 10.1016/s1286-4579(00)01284-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Transformation of T cells by the intracellular parasite Theileria parva is accompanied by constitutive I-kappa B degradation and NF-kappa B activation, a process which is essential to prevent the spontaneous apoptosis of these parasite-transformed cells. NF-kappa B-mediated responses are regulated by selective combinations of NF-kappa B proteins as homo- or heterodimers and by distinct kappa B motifs. We characterised the NF-kappa B complexes induced by T. parva infection in TpM(803) T cells. By western blot, we demonstrated that all members of the NF-kappa B/Rel family of proteins translocate to the nucleus of infected cells. Using two different kappa B oligonucleotides (kappa B-1 and kappa B-2), both containing the decameric consensus kappa B motif (GGGACTTTCC), clearly distinct patterns of DNA binding activities could be demonstrated in electrophoretic mobility shift assays. Supershift analysis and UV cross-linking assays showed that complexes binding to kappa B-1 consisted of p50, p65 and RelB homo and/or heterodimers. We could also detect an association of ATF-2 and c-Fos with one of the complexes. The HIV-derived kappa B-2 oligo only bound p50 and p65. Additionally, several agents known to inhibit a wide range of NF-kappa B activation pathways had no inhibitory effect on the activation of NF-kappa B DNA binding in TpM(803) T cells.
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Affiliation(s)
- J Machado
- Laboratory of Molecular Pathology, Institute of Animal Pathology, University of Berne, Länggass-Strasse 122, 3012, Berne, Switzerland
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38
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Yokota Y, Ikeda M, Higashino K, Nakano K, Fujii N, Arita H, Hanasaki K. Enhanced tissue expression and elevated circulating level of phospholipase A(2) receptor during murine endotoxic shock. Arch Biochem Biophys 2000; 379:7-17. [PMID: 10864436 DOI: 10.1006/abbi.2000.1849] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phospholipase A(2) receptor (PLA(2)R) mediates a variety of biological responses elicited by mammalian secretory phospholipase A(2) (sPLA(2)). In mice, group IB sPLA(2) (sPLA(2)-IB) acts as an endogenous ligand of PLA(2)R, and analysis of PLA(2)R-deficient mice has demonstrated a critical role of the sPLA(2)-IB/PLA(2)R system in the production of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) in the development of endotoxic shock. Here, we generated specific antibodies against a recombinant soluble form of PLA(2)R and examined its expression in the lung and spleen where a remarkable elevation of TNF-alpha expression has been observed during endotoxemia. Immunohistochemical analysis revealed the expression of PLA(2)R in type II alveolar epithelial cells and a subset of splenic lymphocytes, and its expression levels were markedly enhanced at 1 h after endotoxin challenge. Analysis with a newly developed sandwich enzyme-linked immunosorbent assay system revealed the presence of a soluble form of PLA(2)R in plasma of wild-type mice compared with its absence in plasma of PLA(2)R-deficient mice. After exposure to endotoxin, its circulating level was significantly elevated to the maximum level at 2-3 h after the treatment. These results suggest that tissue expression and the circulating level of PLA(2)R are elevated during murine endotoxemia, which might be relevant to its potential roles in the production of proinflammatory mediators during the development of inflammatory conditions.
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Affiliation(s)
- Y Yokota
- Shionogi Research Laboratories, Shionogi & Co., Ltd., Fukushima-ku, Osaka, 553-0002, Japan
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39
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Calzado MA, MacHo A, Lucena C, Muñoz E. Hydroxyurea inhibits the transactivation of the HIV-long-terminal repeat (LTR) promoter. Clin Exp Immunol 2000; 120:317-23. [PMID: 10792382 PMCID: PMC1905657 DOI: 10.1046/j.1365-2249.2000.01203.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
HIV-1 gene expression is regulated by the promoter/enhancer located within the U3 region of the proviral 5' LTR that contains multiple potential cis-acting regulatory sites. Here we describe that the inhibitor of the cellular ribonucleoside reductase, hydroxyurea (HU), inhibited phorbol myristate acetate- or tumour necrosis factor-alpha-induced HIV-1-LTR transactivation in both lymphoid and non-lymphoid cells in a dose-dependent manner within the first 6 h of treatment, with a 50% inhibitory concentration of 0.5 mM. This inhibition was found to be specific for the HIV-1-LTR since transactivation of either an AP-1-dependent promoter or the CD69 gene promoter was not affected by the presence of HU. Moreover, gel-shift assays in 5.1 cells showed that HU prevented the binding of the NF-kappaB to the kappaB sites located in the HIV-1-LTR region, but it did not affect the binding of both the AP-1 and the Sp-1 transcription factors. By Western blots and cell cycle analyses we detected that HU induced a rapid dephosphorylation of the pRB, the product of the retinoblastoma tumour suppressor gene, and the cell cycle arrest was evident after 24 h of treatment. Thus, HU inhibits HIV-1 promoter activity by a novel pathway that implies an inhibition of the NF-kappaB binding to the LTR promoter. The present study suggests that HU may be useful as a potential therapeutic approach for inhibition of HIV-1 replication through different pathways.
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Affiliation(s)
- M A Calzado
- Departamento de Biología Celular, Fisiología e Inmunología, Facultad de Medicina, Universidad de Córdoba, Córdoba, Spain
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Pereira LA, Bentley K, Peeters A, Churchill MJ, Deacon NJ. A compilation of cellular transcription factor interactions with the HIV-1 LTR promoter. Nucleic Acids Res 2000; 28:663-8. [PMID: 10637316 PMCID: PMC102541 DOI: 10.1093/nar/28.3.663] [Citation(s) in RCA: 272] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) represents a model promoter system and the identification and characterisation of cellular proteins that interact with this region has provided a basic understanding about both general eukaryotic and HIV-1 proviral transcriptional regulation. To date a large number of sequence-specific DNA-protein interactions have been described for the HIV-1 LTR. The aim of this report is to provide a comprehensive, updated listing of these HIV-1 LTR interactions. It is intended as a reference point to facilitate on-going studies characterising the identity of cellular proteins interacting with the HIV-1 LTR and the functional role(s) of specific regions of the LTR for HIV-1 replication.
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Affiliation(s)
- L A Pereira
- AIDS Molecular Biology Unit, National Centre for HIV Virology Research, The Macfarlane Burnet Centre for Medical Research, PO Box 254, Fairfield, Victoria 3078, Australia
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41
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Hanasaki K, Arita H. Biological and pathological functions of phospholipase A(2) receptor. Arch Biochem Biophys 1999; 372:215-23. [PMID: 10600158 DOI: 10.1006/abbi.1999.1511] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- K Hanasaki
- Shionogi Research Laboratories, Shionogi and Co., Ltd., Sagisu 5-12-4, Fukushima-ku, Osaka, 553-0002, Japan
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42
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Darbinian N, Gallia GL, Kundu M, Shcherbik N, Tretiakova A, Giordano A, Khalili K. Association of Pur alpha and E2F-1 suppresses transcriptional activity of E2F-1. Oncogene 1999; 18:6398-402. [PMID: 10597240 DOI: 10.1038/sj.onc.1203011] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Protein-protein interaction can play an important role in the control of several biological events including gene transcription, replication and cell proliferation. E2F-1 is a DNA-binding transcription factor which, upon interaction with its target DNA sequence, induces expression of several S phase specific genes allowing progression of the cell cycle. Evidently, the activity of this protein is modulated by its cellular partner, pRb, which in the hypophosphorylated form, binds to E2F-1 and inactivates its transcriptional ability. In this study, we have demonstrated that expression of a sequence-specific single-stranded DNA binding protein, Pur alpha, in cells decreases the ability of E2F-1 to exert its transcriptional activity upon the responsive promoter derived from DHFR. Results from band shift experiments revealed that while Pur alpha does not recognize the double-stranded DNA fragment containing the E2F-1 binding site, it has the ability to inhibit E2F-1 interaction with its target DNA sequence. Results from GST pull-down assays and the combined immunoprecipitation/Western blot analysis of nuclear extracts revealed a direct association of E2F-1 with Pur alpha in the absence of the DNA molecule containing the E2F-1 binding site. The association of Pur alpha with E2F-1 may increase the stability of E2F-1, as a higher level of E2F-1 was detected in cells coexpressing Pur alpha and E2F-1. The importance of these observations with respect to the role of Pur alpha in the control of cell cycle progression is discussed.
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Affiliation(s)
- N Darbinian
- Center for NeuroVirology and NeuroOncology, MCP Hahnemann University School of Medicine, Philadelphia, PA 19102, USA
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43
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Hinz M, Krappmann D, Eichten A, Heder A, Scheidereit C, Strauss M. NF-kappaB function in growth control: regulation of cyclin D1 expression and G0/G1-to-S-phase transition. Mol Cell Biol 1999; 19:2690-8. [PMID: 10082535 PMCID: PMC84062 DOI: 10.1128/mcb.19.4.2690] [Citation(s) in RCA: 622] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nuclear factor kappa B (NF-kappaB) has been implicated in the regulation of cell proliferation, transformation, and tumor development. We provide evidence for a direct link between NF-kappaB activity and cell cycle regulation. NF-kappaB was found to stimulate transcription of cyclin D1, a key regulator of G1 checkpoint control. Two NF-kappaB binding sites in the human cyclin D1 promoter conferred activation by NF-kappaB as well as by growth factors. Both levels and kinetics of cyclin D1 expression during G1 phase were controlled by NF-kappaB. Moreover, inhibition of NF-kappaB caused a pronounced reduction of serum-induced cyclin D1-associated kinase activity and resulted in delayed phosphorylation of the retinoblastoma protein. Furthermore, NF-kappaB promotes G1-to-S-phase transition in mouse embryonal fibroblasts and in T47D mammary carcinoma cells. Impaired cell cycle progression of T47D cells expressing an NF-kappaB superrepressor (IkappaBalphaDeltaN) could be rescued by ectopic expression of cyclin D1. Thus, NF-kappaB contributes to cell cycle progression, and one of its targets might be cyclin D1.
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Affiliation(s)
- M Hinz
- Molekulare Zellbiologie, Humboldt Universität zu Berlin, Max-Delbrück-Haus, 13122 Berlin, Germany
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Verhoef K, Sanders RW, Fontaine V, Kitajima S, Berkhout B. Evolution of the human immunodeficiency virus type 1 long terminal repeat promoter by conversion of an NF-kappaB enhancer element into a GABP binding site. J Virol 1999; 73:1331-40. [PMID: 9882338 PMCID: PMC103957 DOI: 10.1128/jvi.73.2.1331-1340.1999] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) transcription is regulated by the viral Tat protein and cellular factors, of which the concentration and activity may depend on the cell type. Viral long terminal repeat (LTR) promoter sequences are therefore optimized to suit the specific nuclear environment of the target host cell. In long-term cultures of a Tat-defective, poorly replicating HIV-1 mutant, we selected for a faster-replicating virus with a 1-nucleotide deletion in the upstream copy of two highly conserved NF-kappaB binding sites. The variant enhancer sequence demonstrated a severe loss of NF-kappaB binding in protein binding assays. Interestingly, we observed a new binding activity that is specific for the variant NF-kappaB sequence and is present in the nuclear extract of unstimulated cells that lack NF-kappaB. These results suggest that inactivation of the NF-kappaB site coincides with binding of another transcription factor. Fine mapping of the sequence requirements for binding of this factor revealed a core sequence similar to that of Ets binding sites, and supershift assays with antibodies demonstrated the involvement of the GABP transcription factor. Transient transfection experiments with LTR-chloramphenicol acetyltransferase constructs indicated that the variant LTR promoter is specifically inhibited by GABP in the absence of Tat, but this promoter was dramatically more responsive to Tat than the wild-type LTR. Introduction of this GABP site into the LAI virus yielded a specific gain of fitness in SupT1 cells, which contain little NF-kappaB protein. These results suggest that GABP potentiates Tat-mediated activation of LTR transcription and viral replication in some cell types. Conversion of an NF-kappaB into a GABP binding site is likely to have occurred also during the worldwide spread of HIV-1, as we noticed the same LTR modification in subtype E isolates from Thailand. This typical LTR promoter configuration may provide these viruses with unique biological properties.
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Affiliation(s)
- K Verhoef
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
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Sawaya BE, Khalili K, Mercer WE, Denisova L, Amini S. Cooperative actions of HIV-1 Vpr and p53 modulate viral gene transcription. J Biol Chem 1998; 273:20052-7. [PMID: 9685344 DOI: 10.1074/jbc.273.32.20052] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription of the human immunodeficiency virus type-1 (HIV-1) genome is controlled by cooperative interaction of viral encoded proteins and host regulatory proteins. In this study, we have examined the capacity of the viral auxiliary protein, Vpr, to modulate transcriptional activity of the HIV-1 promoter sequence located within the long terminal repeat (LTR). We demonstrate that ectopic expression of Vpr in human astrocytic cells, U-87MG, enhances the basal activity of the viral promoter in transfected cells and that the GC-rich sequences, spanning nucleotides -80 to -43, are important for this activity. Since this region serves as the target for p53-induced suppression of LTR activity and interacts with the ubiquitous transcription factor, Sp1, we examined the cooperative activity of Vpr, p53, and Sp1 upon LTR transcription. Results from co-transfection studies indicated that overexpression of wild type p53, but not mutant p53, decreases the level of activation of the LTR by Vpr. Transcriptional activation of the LTR by Vpr required the presence of Sp1 since overexpression of Vpr in cells with no endogenous Sp1 failed to augment LTR activity. Results from protein-protein interaction studies indicated that Vpr is associated with both p53 and Sp1 in cells with ectopic expression of these proteins. Moreover, it was evident that p53 and Sp1 interact with each other in these cells. These functional and structural studies provided a working model on the cooperative interaction of Vpr with cellular proteins Sp1 and p53 and control of viral gene transcription at immediate early stage of infection prior to the participation of other viral regulatory proteins.
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Affiliation(s)
- B E Sawaya
- Center for NeuroVirology and NeuroOncology, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania 19102, USA
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