1
|
Cho MJ, Lee DG, Lee JW, Hwang B, Yoon SJ, Lee SJ, Park YJ, Park SH, Lee HG, Kim YH, Lee CH, Lee J, Lee NK, Han TS, Cho HS, Moon JH, Lee GS, Bae KH, Hwang GS, Lee SH, Chung SJ, Shim S, Cho J, Oh GT, Kwon YG, Park JG, Min JK. Endothelial PTP4A1 mitigates vascular inflammation via USF1/A20 axis-mediated NF-κB inactivation. Cardiovasc Res 2023; 119:1265-1278. [PMID: 36534975 PMCID: PMC10411943 DOI: 10.1093/cvr/cvac193] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 09/08/2022] [Accepted: 11/08/2022] [Indexed: 12/23/2022] Open
Abstract
AIMS The nuclear factor-κB (NF-κB) signalling pathway plays a critical role in the pathogenesis of multiple vascular diseases. However, in endothelial cells (ECs), the molecular mechanisms responsible for the negative regulation of the NF-κB pathway are poorly understood. In this study, we investigated a novel role for protein tyrosine phosphatase type IVA1 (PTP4A1) in NF-κB signalling in ECs. METHODS AND RESULTS In human tissues, human umbilical artery ECs, and mouse models for loss of function and gain of function of PTP4A1, we conducted histological analysis, immunostaining, laser-captured microdissection assay, lentiviral infection, small interfering RNA transfection, quantitative real-time PCR and reverse transcription-PCR, as well as luciferase reporter gene and chromatin immunoprecipitation assays. Short hairpin RNA-mediated knockdown of PTP4A1 and overexpression of PTP4A1 in ECs indicated that PTP4A1 is critical for inhibiting the expression of cell adhesion molecules (CAMs). PTP4A1 increased the transcriptional activity of upstream stimulatory factor 1 (USF1) by dephosphorylating its S309 residue and subsequently inducing the transcription of tumour necrosis factor-alpha-induced protein 3 (TNFAIP3/A20) and the inhibition of NF-κB activity. Studies on Ptp4a1 knockout or transgenic mice demonstrated that PTP4A1 potently regulates the interleukin 1β-induced expression of CAMs in vivo. In addition, we verified that PTP4A1 deficiency in apolipoprotein E knockout mice exacerbated high-fat high-cholesterol diet-induced atherogenesis with upregulated expression of CAMs. CONCLUSION Our data indicate that PTP4A1 is a novel negative regulator of vascular inflammation by inducing USF1/A20 axis-mediated NF-κB inactivation. Therefore, the expression and/or activation of PTP4A1 in ECs might be useful for the treatment of vascular inflammatory diseases.
Collapse
Affiliation(s)
- Min Ji Cho
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Dong Gwang Lee
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jeong Woong Lee
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Byungtae Hwang
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sung-Jin Yoon
- Environmental Disease Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Seon-Jin Lee
- Environmental Disease Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Young-Jun Park
- Environmental Disease Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Seung-Ho Park
- Environmental Disease Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hee Gu Lee
- Immunotherapy Convergence Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Yong-Hoon Kim
- Laboratory Animal Resource Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Chul-Ho Lee
- Laboratory Animal Resource Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jangwook Lee
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Nam-Kyung Lee
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Tae-Su Han
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hyun-Soo Cho
- Stem Cell Convergence Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jeong Hee Moon
- Disease Target Structure Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Ga Seul Lee
- Disease Target Structure Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Kwang-Hee Bae
- Metabolic Regulation Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Geum-Sook Hwang
- Integrated Metabolomics Research Group, Western Seoul Centre, Korea Basic Science Institute, 150 Bugahyeon-ro, Seodaemun-gu, Seoul 03759, Republic of Korea
| | - Sang-Hak Lee
- Division of Cardiology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Sang J Chung
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Sungbo Shim
- Department of Biochemistry, Chungbuk National University, 1 Chungdae-ro, Seowon-gu, Cheongju 28644, Republic of Korea
| | - Jaehyung Cho
- Division of Haematology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Goo Taeg Oh
- Heart-Immune-Brain Network Research Centre, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 03760, Republic of Korea
| | - Young-Guen Kwon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Jong-Gil Park
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
- Department of Bioscience, KRIBB School of Bioscience, Korea University of Science and Technology (UST), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jeong-Ki Min
- Biotherapeutics Translational Research Centre, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
- Department of Bioscience, KRIBB School of Bioscience, Korea University of Science and Technology (UST), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| |
Collapse
|
2
|
Fischer A, Manske K, Seissler J, Wohlleber D, Simm N, Wolf-van Buerck L, Knolle P, Schnieke A, Fischer K. Cytokine-inducible promoters to drive dynamic transgene expression: The "Smart Graft" strategy. Xenotransplantation 2020; 27:e12634. [PMID: 32808410 DOI: 10.1111/xen.12634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/03/2020] [Accepted: 07/20/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Ubiquitous expression of T-cell regulatory transgenes such as the cytotoxic T lymphocyte-associated antigen 4 (CTLA4) or the high-affinity variant LEA29Y improves xeno graft survival. Such donor pigs are however immunocompromised and susceptible to infection. Continous high expression of CTLA4 or LEA29Y in the graft could also compromise the health status of recipients. The novel "Smart Graft" strategy is likely to avoid these problems by controlling the expression of T-cell regulatory transgenes as and when required. METHODS Candidate promoters inducible by inflammatory cytokines were identified by in silico screening for potential NF-κB binding sites. Basal promoter levels and responsiveness to TNFα and IL1ß were quantified by expression of secreted embryonic alkaline phosphatase in cultured cells. Promoters were modified to increase responsiveness by removing regulatory elements or adding SP-1 or NF-κB binding sites and again tested in vitro. The most promising promoters were then assessed in vivo. Porcine cells expressing inducible Renilla luciferase constructs were transplanted into immunodeficient NOD-Scid-IL2 receptor gammanull (NSG) mice. Following engraftment, the recipient's immune system was reconstituted by splenocyte transfer raising an immune response to the porcine xenograft. The resulting induction of promoter activity was detected by in vivo bioimaging. RESULTS Three human (hTNFAIP1, hVCAM1 and hCCL2), and one porcine promoter (pA20) were chosen for in vitro tests. In all experiments, the semi-synthetic and inducible ELAM promoter as well as the CAG promoter were used as references. In contrast to hTNFAIP1 and hVCAM1 the ELAM, hCCL2 and pA20 promoters showed significant induction after cytokine challenge. The hCCL2 and pA20 promoters were further optimized, resulting in increased responsiveness to TNFα and IL1ß. Cytokine-dependent upregulation of promoter activity was tested in vivo, where the ELAM and the optimized hCCL2 promoters showed a 2-fold upregulation, while one of the improved A20 promoters showed almost 10-fold upregulation. Our results also revealed more than 4-fold cytokine inducibility of the CAG promoter. CONCLUSION This is the first in vivo comparison of existing and newly designed cytokine-inducible promoters. Optimization of promoter structure resulted in almost 10-fold inducibility of promoter activity. Such a rapid and dynamically regulated response to inflammation and cell damage could reduce initial graft rejection, making the "Smart Graft" approach a useful means of modulating the expression of immune regulatory transgenes to avoid deleterious effects on porcine and human health. Expressing transgenes in this fashion could provide a safer organ for transplantation.
Collapse
Affiliation(s)
- Andrea Fischer
- Livestock Biotechnology, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Katrin Manske
- Institute of Molecular Immunology and Experimental Oncology, Technische Universität München, Munich, Germany
| | - Jochen Seissler
- Diabetes Center, Medizinische Klinik und Polyklinik IV, Klinikum der Universität München, Munich, Germany
| | - Dirk Wohlleber
- Institute of Molecular Immunology and Experimental Oncology, Technische Universität München, Munich, Germany
| | - Nina Simm
- Livestock Biotechnology, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Lelia Wolf-van Buerck
- Diabetes Center, Medizinische Klinik und Polyklinik IV, Klinikum der Universität München, Munich, Germany
| | - Percy Knolle
- Institute of Molecular Immunology and Experimental Oncology, Technische Universität München, Munich, Germany
| | - Angelika Schnieke
- Livestock Biotechnology, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Konrad Fischer
- Livestock Biotechnology, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| |
Collapse
|
3
|
de Jesús TJ, Ramakrishnan P. NF-κB c-Rel Dictates the Inflammatory Threshold by Acting as a Transcriptional Repressor. iScience 2020; 23:100876. [PMID: 32062419 PMCID: PMC7031323 DOI: 10.1016/j.isci.2020.100876] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 01/11/2020] [Accepted: 01/28/2020] [Indexed: 12/14/2022] Open
Abstract
NF-κB/Rel family of transcription factors plays a central role in initiation and resolution of inflammatory responses. Here, we identified a function of the NF-κB subunit c-Rel as a transcriptional repressor of inflammatory genes. Genetic deletion of c-Rel substantially potentiates the expression of several TNF-α-induced RelA-dependent mediators of inflammation. v-Rel, the viral homologue of c-Rel, but not RelB, also possesses this repressive function. Mechanistically, we found that c-Rel selectively binds to the co-repressor HDAC1 and competitively binds to the DNA mediating HDAC1 recruitment to the promoters of inflammatory genes. A specific point mutation at tyrosine25 in c-Rel's DNA-binding domain, for which a missense single nucleotide variation (Y25H) exists in humans, completely abrogated its ability to bind DNA and repress TNF-α-induced, RelA-mediated transcription. Our findings reveal that the transactivator NF-κB subunit c-Rel also plays a role as a transcriptional repressor in the maintenance of inflammatory homeostasis.
Collapse
Affiliation(s)
- Tristan James de Jesús
- Department of Pathology, School of Medicine, Case Western Reserve University and University Hospitals Cleveland Medical Center, 6526, Wolstein Research Building, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Parameswaran Ramakrishnan
- Department of Pathology, School of Medicine, Case Western Reserve University and University Hospitals Cleveland Medical Center, 6526, Wolstein Research Building, 2103 Cornell Road, Cleveland, OH 44106, USA; Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; The Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| |
Collapse
|
4
|
Felwick RK, Dingley GJR, Martinez-Nunez R, Sanchez-Elsner T, Cummings JRF, Collins JE. MicroRNA23a Overexpression in Crohn's Disease Targets Tumour Necrosis Factor Alpha Inhibitor Protein 3, Increasing Sensitivity to TNF and Modifying the Epithelial Barrier. J Crohns Colitis 2020; 14:381-392. [PMID: 31626694 DOI: 10.1093/ecco-jcc/jjz145] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Mucosal healing is important in Crohn's disease therapies. Epithelial homeostasis becomes dysregulated in Crohn's, with increased permeability, inflammation, and diarrhoea. MicroRNAs are small non-coding RNAs that regulate gene expression and show changes in inflammatory bowel disease. Tumour necrosis factor alpha [TNFα] inhibitor protein 3 is raised in Crohn's and regulates TNFα-mediated activation of NFκB. We investigated TNFα regulation by microRNA in Crohn's disease [CD], and studied effects on epithelial permeability and inflammation. METHODS Colonic epithelium from CD and healthy donor biopsies was isolated using laser capture microdissection, and microRNA was quantified. Tumour necrosis factor alpha inhibitor protein 3 was characterised immunohistochemically on serial sections. Expression effect of microRNA was confirmed with luciferase reporter assays. Functional barrier permeability studies and innate cytokine release were investigated with cell and explant culture studies. RESULTS MicroRNA23a levels significantly increased in colonic Crohn's epithelium compared with healthy epithelium. Luciferase reporter assays in transfected epithelial cells confirmed that microRNA23a repressed expression via the 3' untranslated region of tumour necrosis factor alpha inhibitor protein 3 mRNA, coinciding with increased NFκB-mediated transcription. Immunohistochemical staining of TNFAIP3 protein in colonic biopsies was reduced or absent in adjacent Crohn's sections, correlating inversely with microRNA23a levels and encompassing some intercohort variation. Overexpression of microRNA23a increased epithelial barrier permeability in a colonic epithelial model and increased inflammatory cytokine release in cultured explant biopsies, mimicking Crohn's disease characteristics. CONCLUSIONS MicroRNA23a overexpression in colonic Crohn's epithelium represses tumour necrosis factor alpha inhibitor protein 3, enhancing sensitivity to TNFα, with increased intestinal permeability and cytokine release.
Collapse
Affiliation(s)
- Richard K Felwick
- Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton, UK.,Gastroenterology, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Geraint J R Dingley
- Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton, UK.,Wessex Renal and Transplant Unit, Queen Alexandra Hospital, Cosham, Portsmouth, UK
| | - Rocio Martinez-Nunez
- Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton, UK.,MRC-Asthma UK Centre, King's College London, London, UK
| | - Tilman Sanchez-Elsner
- Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton, UK
| | - J R Fraser Cummings
- Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton, UK.,Gastroenterology, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Jane E Collins
- Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton, UK
| |
Collapse
|
5
|
Martens A, van Loo G. A20 at the Crossroads of Cell Death, Inflammation, and Autoimmunity. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a036418. [PMID: 31427375 DOI: 10.1101/cshperspect.a036418] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A20 is a potent anti-inflammatory protein, acting by inhibiting nuclear factor κB (NF-κB) signaling and inflammatory gene expression and/or by preventing cell death. Mutations in the A20/TNFAIP3 gene have been associated with a plethora of inflammatory and autoimmune pathologies in humans and in mice. Although the anti-inflammatory role of A20 is well accepted, fundamental mechanistic questions regarding its mode of action remain unclear. Here, we review new findings that further clarify the molecular and cellular mechanisms by which A20 controls inflammatory signaling and cell death, and discuss new evidence for its involvement in inflammatory and autoimmune disease development.
Collapse
Affiliation(s)
- Arne Martens
- VIB Center for Inflammation Research, 9052 Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Geert van Loo
- VIB Center for Inflammation Research, 9052 Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| |
Collapse
|
6
|
Bahat A, Lahav O, Plotnikov A, Leshkowitz D, Dikstein R. Targeting Spt5-Pol II by Small-Molecule Inhibitors Uncouples Distinct Activities and Reveals Additional Regulatory Roles. Mol Cell 2019; 76:617-631.e4. [PMID: 31564557 DOI: 10.1016/j.molcel.2019.08.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 06/12/2019] [Accepted: 08/26/2019] [Indexed: 12/27/2022]
Abstract
Spt5 is a conserved and essential transcription elongation factor that promotes promoter-proximal pausing, promoter escape, elongation, and mRNA processing. Spt5 plays specific roles in the transcription of inflammation and stress-induced genes and tri-nucleotide expanded-repeat genes involved in inherited neurological pathologies. Here, we report the identification of Spt5-Pol II small-molecule inhibitors (SPIs). SPIs faithfully reproduced Spt5 knockdown effects on promoter-proximal pausing, NF-κB activation, and expanded-repeat huntingtin gene transcription. Using SPIs, we identified Spt5 target genes that responded with profoundly diverse kinetics. SPIs uncovered the regulatory role of Spt5 in metabolism via GDF15, a food intake- and body weight-inhibitory hormone. SPIs further unveiled a role for Spt5 in promoting the 3' end processing of histone genes. While several SPIs affect all Spt5 functions, a few inhibit a single one, implying uncoupling and selective targeting of Spt5 activities. SPIs expand the understanding of Spt5-Pol II functions and are potential drugs against metabolic and neurodegenerative diseases.
Collapse
Affiliation(s)
- Anat Bahat
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Or Lahav
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Plotnikov
- The Nancy and Stephen Grand Israel National Center for Personalized Medicine, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dena Leshkowitz
- Bioinformatics Unit, Department of Life Sciences Core Facilities, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rivka Dikstein
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
| |
Collapse
|
7
|
Lee J, Chan ST, Kim JY, Ou JHJ. Hepatitis C Virus Induces the Ubiquitin-Editing Enzyme A20 via Depletion of the Transcription Factor Upstream Stimulatory Factor 1 To Support Its Replication. mBio 2019; 10:e01660-19. [PMID: 31337730 PMCID: PMC6650561 DOI: 10.1128/mbio.01660-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 06/28/2019] [Indexed: 12/27/2022] Open
Abstract
Tumor necrosis factor alpha-induced protein 3 (TNFAIP3), also known as A20, is a ubiquitin-editing enzyme capable of ubiquitination or deubiquitination of its target proteins. In this study, we show that hepatitis C virus (HCV) infection could induce the expression of A20 via the activation of the A20 promoter. The induction of A20 by HCV coincided with the loss of upstream stimulatory factor 1 (USF-1), a transcription factor known to suppress the A20 promoter. The role of USF-1 in the regulation of the A20 promoter in HCV-infected cells was confirmed by the chromatin immunoprecipitation (ChIP) assay, and its depletion was apparently mediated by proteasomes, as USF-1 could be stabilized by the proteasome inhibitor MG132 to suppress the A20 expression. As the overexpression of A20 enhanced the replication of HCV and the silencing of A20 had the opposite effect, A20 is a positive regulator of HCV replication. Our further studies indicated that A20 enhanced the activity of the HCV internal ribosome entry site (IRES). In conclusion, our results demonstrated that HCV could induce the expression of A20 via the depletion of USF-1 to enhance its replication. Our study provided important information for further understanding the interaction between HCV and its host cells.IMPORTANCE Hepatitis C virus establishes chronic infection in approximately 85% of the patients whom it infects. However, the mechanism of how HCV evades host immunity to establish persistence is unclear. In this report, we demonstrate that HCV could induce the expression of the ubiquitin-editing enzyme A20, an important negative regulator of the tumor necrosis factor alpha (TNF-α) and NF-κB signaling pathways. This induction of A20 enhanced HCV replication as it could stimulate the HCV IRES activity to enhance the translation of HCV proteins. The induction of A20 was mediated by the depletion of USF-1, a suppressor of the A20 promoter. Our study thus provides important information for further understanding the interaction between HCV and its host cells.
Collapse
Affiliation(s)
- Jiyoung Lee
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Stephanie T Chan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Ja Yeon Kim
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jing-Hsiung James Ou
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| |
Collapse
|
8
|
Mouton-Liger F, Rosazza T, Sepulveda-Diaz J, Ieang A, Hassoun SM, Claire E, Mangone G, Brice A, Michel PP, Corvol JC, Corti O. Parkin deficiency modulates NLRP3 inflammasome activation by attenuating an A20-dependent negative feedback loop. Glia 2018; 66:1736-1751. [PMID: 29665074 PMCID: PMC6190839 DOI: 10.1002/glia.23337] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/16/2018] [Accepted: 03/19/2018] [Indexed: 12/13/2022]
Abstract
Neuroinflammation and mitochondrial dysfunction, key mechanisms in the
pathogenesis of Parkinson's disease (PD), are usually explored independently.
Loss‐of‐function mutations of PARK2 and PARK6,
encoding the E3 ubiquitin protein ligase Parkin and the mitochondrial
serine/threonine kinase PINK1, account for a large proportion of cases of autosomal
recessive early‐onset PD. PINK1 and Parkin regulate mitochondrial quality control and
have been linked to the modulation of innate immunity pathways. We report here an
exacerbation of NLRP3 inflammasome activation by specific inducers in microglia and
bone marrow‐derived macrophages from Park2−/− and Pink1−/− mice. The caspase 1‐dependent release of IL‐1β and IL‐18 was, therefore,
enhanced in Park2−/− and Pink1−/− cells. This defect was confirmed in blood‐derived macrophages from patients
with PARK2 mutations and was reversed by MCC950, which specifically
inhibits NLRP3 inflammasome complex formation. Enhanced NLRP3 signaling in
Parkin‐deficient cells was accompanied by a lack of induction of A20, a well‐known
negative regulator of the NF‐κB pathway recently shown to attenuate NLRP3
inflammasome activity. We also found an inverse correlation between A20 abundance and
IL‐1β release, in human macrophages challenged with NLRP3 inflammasome inducers.
Overall, our observations suggest that the A20/NLRP3‐inflammasome axis participates
in the pathogenesis of PARK2‐linked PD, paving the way for the
exploration of its potential as a biomarker and treatment target.
Collapse
Affiliation(s)
- François Mouton-Liger
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| | - Thibault Rosazza
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| | - Julia Sepulveda-Diaz
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| | - Amélie Ieang
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| | - Sidi-Mohamed Hassoun
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| | - Emilie Claire
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| | - Graziella Mangone
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France.,AP-HP, Hôpital de la Pitié Salpêtrière, Clinical Investigation Center of Neurology (CIC-1422), Department of Neurology, Hôpital Pitié-Salpêtrière, Paris, F-75013, France
| | - Alexis Brice
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| | - Patrick P Michel
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| | - Jean-Christophe Corvol
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France.,AP-HP, Hôpital de la Pitié Salpêtrière, Clinical Investigation Center of Neurology (CIC-1422), Department of Neurology, Hôpital Pitié-Salpêtrière, Paris, F-75013, France
| | - Olga Corti
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France.,Inserm, U1127, Paris, F-75013, France.,CNRS, UMR 7225, Paris, F-75013, France.,Sorbonne Universités, Paris, F-75013, France
| |
Collapse
|
9
|
Diamant G, Bahat A, Dikstein R. The elongation factor Spt5 facilitates transcription initiation for rapid induction of inflammatory-response genes. Nat Commun 2016; 7:11547. [PMID: 27180651 PMCID: PMC4873663 DOI: 10.1038/ncomms11547] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 04/07/2016] [Indexed: 12/11/2022] Open
Abstract
A subset of inflammatory-response NF-κB target genes is activated immediately following pro-inflammatory signal. Here we followed the kinetics of primary transcript accumulation after NF-κB activation when the elongation factor Spt5 is knocked down. While elongation rate is unchanged, the transcript synthesis at the 5'-end and at the earliest time points is delayed and reduced, suggesting an unexpected role in early transcription. Investigating the underlying mechanism reveals that the induced TFIID-promoter association is practically abolished by Spt5 depletion. This effect is associated with a decrease in promoter-proximal H3K4me3 and H4K5Ac histone modifications that are differentially required for rapid transcriptional induction. In contrast, the displacement of TFIIE and Mediator, which occurs during promoter escape, is attenuated in the absence of Spt5. Our findings are consistent with a central role of Spt5 in maintenance of TFIID-promoter association and promoter escape to support rapid transcriptional induction and re-initiation of inflammatory-response genes.
Collapse
Affiliation(s)
- Gil Diamant
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7600, Israel
| | - Anat Bahat
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7600, Israel
| | - Rivka Dikstein
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7600, Israel
| |
Collapse
|
10
|
Analysis of Subcellular RNA Fractions Revealed a Transcription-Independent Effect of Tumor Necrosis Factor Alpha on Splicing, Mediated by Spt5. Mol Cell Biol 2016; 36:1342-53. [PMID: 26903558 DOI: 10.1128/mcb.01117-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/16/2016] [Indexed: 12/21/2022] Open
Abstract
The proinflammatory cytokine tumor necrosis factor alpha (TNF-α) modulates the expression of many genes, primarily through activation of NF-κB. Here, we examined the global effects of the elongation factor Spt5 on nascent and mature mRNAs of TNF-α-induced cells using chromatin and cytosolic subcellular fractions. We identified several classes of TNF-α-induced genes controlled at the level of transcription, splicing, and chromatin retention. Spt5 was found to facilitate splicing and chromatin release in genes displaying high induction rates. Further analysis revealed striking effects of TNF-α on the splicing of 25% of expressed genes; the vast majority were not transcriptionally induced. Splicing enhancement of noninduced genes by TNF-α was transient and independent of NF-κB. Investigating the underlying basis, we found that Spt5 is required for the splicing facilitation of the noninduced genes. In line with this, Spt5 interacts with Sm core protein splicing factors. Furthermore, following TNF-α treatment, levels of RNA polymerase II (Pol II) but not Spt5 are reduced from the splicing-induced genes, suggesting that these genes become enriched with a Pol II-Spt5 form. Our findings revealed the Pol II-Spt5 complex as a highly competent coordinator of cotranscriptional splicing.
Collapse
|
11
|
Tiruppathi C, Soni D, Wang DM, Xue J, Singh V, Thippegowda PB, Cheppudira BP, Mishra RK, Debroy A, Qian Z, Bachmaier K, Zhao YY, Christman JW, Vogel SM, Ma A, Malik AB. The transcription factor DREAM represses the deubiquitinase A20 and mediates inflammation. Nat Immunol 2014; 15:239-47. [PMID: 24487321 PMCID: PMC4005385 DOI: 10.1038/ni.2823] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/02/2014] [Indexed: 12/14/2022]
Abstract
Here we show that the transcription-repressor DREAM binds to the A20 promoter to repress the expression of A20, the deubiquitinase suppressing inflammatory NF-κB signaling. DREAM-deficient (Dream−/−) mice displayed persistent and unchecked A20 expression in response to endotoxin. DREAM functioned by transcriptionally repressing A20 through binding to downstream regulatory elements (DREs). In contrast, USF1 binding to the DRE-associated E-box domain activated A20 expression in response to inflammatory stimuli. These studies define the critical opposing functions of DREAM and USF1 in inhibiting and inducing A20 expression, respectively, and thereby the strength of NF-κB signaling. Targeting of DREAM to induce USF1-mediated A20 expression is therefore a potential anti-inflammatory strategy in diseases such as acute lung injury associated with unconstrained NF-κB activity.
Collapse
Affiliation(s)
- Chinnaswamy Tiruppathi
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Dheeraj Soni
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Dong-Mei Wang
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Jiaping Xue
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Vandana Singh
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Prabhakar B Thippegowda
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Bopaiah P Cheppudira
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Rakesh K Mishra
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Auditi Debroy
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Zhijian Qian
- Department of Hematology/Oncology, College of Medicine, University of Illinois, Chicago, Illinois, USA
| | - Kurt Bachmaier
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - You-Yang Zhao
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - John W Christman
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Stephen M Vogel
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Averil Ma
- Department of Medicine, School of Medicine, University of California at San Francisco, San Francisco, California, USA
| | - Asrar B Malik
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| |
Collapse
|
12
|
Diamant G, Dikstein R. Transcriptional control by NF-κB: elongation in focus. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:937-45. [PMID: 23624258 DOI: 10.1016/j.bbagrm.2013.04.007] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/15/2013] [Accepted: 04/17/2013] [Indexed: 01/01/2023]
Abstract
The NF-κB family of transcription factors governs the cellular reaction to a variety of extracellular signals. Following stimulation, NF-κB activates genes involved in inflammation, cell survival, cell cycle, immune cell homeostasis and more. This review focuses on studies of the past decade that uncover the transcription elongation process as a key regulatory stage in the activation pathway of NF-κB. Of interest are studies that point to the elongation phase as central to the selectivity of target gene activation by NF-κB. Particularly, the cascade leading to phosphorylation and acetylation of the NF-κB subunit p65 on serine 276 and lysine 310, respectively, was shown to mediate the recruitment of Brd4 and P-TEFb to many pro-inflammatory target genes, which in turn facilitate elongation and mRNA processing. On the other hand, some anti-inflammatory genes are refractory to this pathway and are dependent on the elongation factor DSIF for efficient elongation and mRNA processing. While these studies have advanced our knowledge of NF-κB transcriptional activity, they have also raised unresolved issues regarding the specific genomic and physiological contexts by which NF-κB utilizes different mechanisms for activation.
Collapse
Affiliation(s)
- Gil Diamant
- Dept. of Biological Chemistry, The Weizmann Institute of Science, Rehovot , Israel
| | | |
Collapse
|
13
|
Kang MS, Yu SL, Kim HY, Lim HS, Lee SK. SPT4 increases UV-induced mutagenesis in yeast through impaired nucleotide excision repair. Mol Cell Toxicol 2013. [DOI: 10.1007/s13273-013-0006-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
14
|
Hartzog GA, Fu J. The Spt4-Spt5 complex: a multi-faceted regulator of transcription elongation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:105-15. [PMID: 22982195 DOI: 10.1016/j.bbagrm.2012.08.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/21/2012] [Accepted: 08/29/2012] [Indexed: 10/27/2022]
Abstract
In all domains of life, elongating RNA polymerases require the assistance of accessory factors to maintain their processivity and regulate their rate. Among these elongation factors, the Spt5/NusG factors stand out. Members of this protein family appear to be the only transcription accessory proteins that are universally conserved across all domains of life. In archaea and eukaryotes, Spt5 associates with a second protein, Spt4. In addition to regulating elongation, the eukaryotic Spt4-Spt5 complex appears to couple chromatin modification states and RNA processing to transcription elongation. This review discusses the experimental bases for our current understanding of Spt4-Spt5 function and recent studies that are beginning to elucidate the structure of Spt4-Spt5/RNA polymerase complexes and mechanism of Spt4-Spt5 action. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
Collapse
Affiliation(s)
- Grant A Hartzog
- Department of MCD Biology, University of California, Santa Cruz, CA 95064, USA.
| | | |
Collapse
|
15
|
Context-Dependent Regulation of Autophagy by IKK-NF-κB Signaling: Impact on the Aging Process. Int J Cell Biol 2012; 2012:849541. [PMID: 22899934 PMCID: PMC3412117 DOI: 10.1155/2012/849541] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/21/2012] [Indexed: 12/19/2022] Open
Abstract
The NF-κB signaling system and the autophagic degradation pathway are crucial cellular survival mechanisms, both being well conserved during evolution. Emerging studies have indicated that the IKK/NF-κB signaling axis regulates autophagy in a context-dependent manner. IKK complex and NF-κB can enhance the expression of Beclin 1 and other autophagy-related proteins and stimulate autophagy whereas as a feedback response, autophagy can degrade IKK components. Moreover, NF-κB signaling activates the expression of autophagy inhibitors (e.g., A20 and Bcl-2/xL) and represses the activators of autophagy (BNIP3, JNK1, and ROS). Several studies have indicated that NF-κB signaling is enhanced both during aging and cellular senescence, inducing a proinflammatory phenotype. The aging process is also associated with a decline in autophagic degradation. It seems that the activity of Beclin 1 initiation complex could be impaired with aging, since the expression of Beclin 1 decreases as does the activity of type III PI3K. On the other hand, the expression of inhibitory Bcl-2/xL proteins increases with aging. We will review the recent literature on the control mechanisms of autophagy through IKK/NF-κB signaling and emphasize that NF-κB signaling could be a potent repressor of autophagy with ageing.
Collapse
|
16
|
Abstract
The core promoter of eukaryotic coding and non-coding genes that are transcribed by RNA polymerase II (RNAP II) is composed of DNA elements surrounding the transcription start site. These elements serve as the docking site of the basal transcription machinery and have an important role in determining the position and directing the rate of transcription initiation. This review summarizes the current knowledge about core promoter elements and focuses on several unexpected links between core promoter structure and certain gene features. These include the association between the presence or absence of a TATA-box and gene length, gene structure, gene function, evolution rate and transcription elongation.
Collapse
Affiliation(s)
- Rivka Dikstein
- Department of Biological Chemistry, The Weizmann Institute of Science; Rehovot, Israel.
| |
Collapse
|
17
|
Golan-Mashiach M, Grunspan M, Emmanuel R, Gibbs-Bar L, Dikstein R, Shapiro E. Identification of CTCF as a master regulator of the clustered protocadherin genes. Nucleic Acids Res 2011; 40:3378-91. [PMID: 22210889 PMCID: PMC3333863 DOI: 10.1093/nar/gkr1260] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The brain is a large and complex network of neurons. Specific neuronal connectivity is thought to be based on the combinatorial expression of the 52 protocadherins (Pcdh) membrane adhesion proteins, whereby each neuron expresses only a specific subset. Pcdh genes are arranged in tandem, in a cluster of three families: Pcdhα, Pcdhβ and Pcdhγ. The expression of each Pcdh gene is regulated by a promoter that has a regulatory conserved sequence element (CSE), common to all 52 genes. The mechanism and factors controlling individual Pcdh gene expression are currently unknown. Here we show that the promoter of each Pcdh gene contains a gene-specific conserved control region, termed specific sequence element (SSE), located adjacent and upstream to the CSE and activates transcription together with the CSE. We purified the complex that specifically binds the SSE-CSE region and identified the CCTC binding-factor (CTCF) as a key molecule that binds and activates Pcdh promoters. Our findings point to CTCF as a factor essential for Pcdh expression and probably governing neuronal connectivity.
Collapse
Affiliation(s)
- Michal Golan-Mashiach
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | | | | | | | |
Collapse
|
18
|
Matta H, Gopalakrishnan R, Punj V, Yi H, Suo Y, Chaudhary PM. A20 is induced by Kaposi sarcoma-associated herpesvirus-encoded viral FLICE inhibitory protein (vFLIP) K13 and blocks K13-induced nuclear factor-kappaB in a negative feedback manner. J Biol Chem 2011; 286:21555-64. [PMID: 21531730 DOI: 10.1074/jbc.m111.224048] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of A20, a negative regulator of the NF-κB pathway, is frequently lost in several subtypes of Hodgkin and non-Hodgkin lymphoma. We report that A20 is expressed in Kaposi sarcoma-associated herpesvirus (KSHV)-infected primary effusion lymphoma cell lines, and its expression correlates closely with the expression of KSHV-encoded viral FLICE inhibitory protein K13. Ectopic expression of K13 induced A20 expression through NF-κB-mediated activation of A20 promoter. In turn, A20 blocked K13-induced NF-κB activity and up-regulation of proinflammatory cytokines CCL20 and IL-8 in a negative feedback fashion. Both the N-terminal deubiquitinating domain and the C-terminal zinc finger domain of A20 were involved in the inhibition of K13-induced NF-κB activity. Overexpression of A20 blocked K13-induced IκBα phosphorylation, NF-κB nuclear translocation, and cellular transformation. Consistent with the above, K13-induced IκBα phosphorylation and NF-κB transcriptional activation were enhanced in A20-deficient cells. Finally, A20 was found to interact physically with K13. Taken collectively, these results demonstrate that K13 is a key determinant of A20 expression in KSHV-infected cells, and A20 is a key negative regulator of K13-induced NF-κB activity. A20 might serve to control the inflammatory response to KSHV infection and protect KSHV-infected cells from apoptosis.
Collapse
Affiliation(s)
- Hittu Matta
- Jane Ann Nohl Division of Hematology and Center for the Study of Blood Diseases, University of Southern California Keck School of Medicine, Los Angeles, California 90033, USA
| | | | | | | | | | | |
Collapse
|
19
|
Pavri R, Gazumyan A, Jankovic M, Di Virgilio M, Klein I, Ansarah-Sobrinho C, Resch W, Yamane A, Reina San-Martin B, Barreto V, Nieland TJ, Root DE, Casellas R, Nussenzweig MC. Activation-induced cytidine deaminase targets DNA at sites of RNA polymerase II stalling by interaction with Spt5. Cell 2010; 143:122-33. [PMID: 20887897 DOI: 10.1016/j.cell.2010.09.017] [Citation(s) in RCA: 283] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 08/02/2010] [Accepted: 09/13/2010] [Indexed: 11/30/2022]
Abstract
Activation-induced cytidine deaminase (AID) initiates antibody gene diversification by creating U:G mismatches. However, AID is not specific for antibody genes; Off-target lesions can activate oncogenes or cause chromosome translocations. Despite its importance in these transactions little is known about how AID finds its targets. We performed an shRNA screen to identify factors required for class switch recombination (CSR) of antibody loci. We found that Spt5, a factor associated with stalled RNA polymerase II (Pol II) and single stranded DNA (ssDNA), is required for CSR. Spt5 interacts with AID, it facilitates association between AID and Pol II, and AID recruitment to its Ig and non-Ig targets. ChIP-seq experiments reveal that Spt5 colocalizes with AID and stalled Pol II. Further, Spt5 accumulation at sites of Pol II stalling is predictive of AID-induced mutation. We propose that AID is targeted to sites of Pol II stalling in part via its association with Spt5.
Collapse
Affiliation(s)
- Rushad Pavri
- Laboratory of Molecular Immunology, The Rockefeller University, New York, New York 10065, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Verstrepen L, Verhelst K, van Loo G, Carpentier I, Ley SC, Beyaert R. Expression, biological activities and mechanisms of action of A20 (TNFAIP3). Biochem Pharmacol 2010; 80:2009-20. [PMID: 20599425 DOI: 10.1016/j.bcp.2010.06.044] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 06/22/2010] [Accepted: 06/25/2010] [Indexed: 12/17/2022]
Abstract
A20 (also known as TNFAIP3) is a cytoplasmic protein that plays a key role in the negative regulation of inflammation and immunity. Polymorphisms in the A20 gene locus have been identified as risk alleles for multiple human autoimmune diseases, and A20 has also been proposed to function as a tumor suppressor in several human B-cell lymphomas. A20 expression is strongly induced by multiple stimuli, including the proinflammatory cytokines TNF and IL-1, and microbial products that trigger pathogen recognition receptors, such as Toll-like receptors. A20 functions in a negative feedback loop, which mediates its inhibitory functions by downregulating key proinflammatory signaling pathways, including those controlling NF-κB- and IRF3-dependent gene expression. Activation of these transcription factors is controlled by both K48- and K63- polyubiquitination of upstream signaling proteins, respectively triggering proteasome-mediated degradation or interaction with other signaling proteins. A20 turns off NF-κB and IRF3 activation by modulating both types of ubiquitination. Induction of K48-polyubiquitination by A20 involves its C-terminal zinc-finger ubiquitin-binding domain, which may promote interaction with E3 ligases, such as Itch and RNF11 that are involved in mediating A20 inhibitory functions. A20 is thought to promote de-ubiquitination of K63-polyubiquitin chains either directly, due to its N-terminal deubiquitinase domain, or by disrupting the interaction between E3 and E2 enzymes that catalyze K63-polyubiquitination. A20 is subject to different mechanisms of regulation, including phosphorylation, proteolytic processing, and association with ubiquitin binding proteins. Here we review the expression and biological activities of A20, as well as the underlying molecular mechanisms.
Collapse
Affiliation(s)
- Lynn Verstrepen
- Unit of Molecular Signal Transduction in Inflammation, Department for Molecular Biomedical Research, VIB, Technologiepark 927, 9000 Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
21
|
Valentine R, Dawson CW, Hu C, Shah KM, Owen TJ, Date KL, Maia SP, Shao J, Arrand JR, Young LS, O'Neil JD. Epstein-Barr virus-encoded EBNA1 inhibits the canonical NF-kappaB pathway in carcinoma cells by inhibiting IKK phosphorylation. Mol Cancer 2010; 9:1. [PMID: 20051109 PMCID: PMC2818691 DOI: 10.1186/1476-4598-9-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 01/05/2010] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The Epstein-Barr virus (EBV)-encoded EBNA1 protein is expressed in all EBV-associated tumours, including undifferentiated nasopharyngeal carcinoma (NPC), where it is indispensable for viral replication, genome maintenance and viral gene expression. EBNA1's transcription factor-like functions also extend to influencing the expression of cellular genes involved in pathways commonly dysregulated during oncogenesis, including elevation of AP-1 activity in NPC cell lines resulting in enhancement of angiogenesis in vitro. In this study we sought to extend these observations by examining the role of EBNA1 upon another pathway commonly deregulated during carcinogenesis; namely NF-kappaB. RESULTS In this report we demonstrate that EBNA1 inhibits the canonical NF-kappaB pathway in carcinoma lines by inhibiting the phosphorylation of IKKalpha/beta. In agreement with this observation we find a reduction in the phosphorylation of IkappaBalpha and reduced phosphorylation and nuclear translocation of p65, resulting in a reduction in the amount of p65 in nuclear NF-kappaB complexes. Similar effects were also found in carcinoma lines infected with recombinant EBV and in the EBV-positive NPC-derived cell line C666-1. Inhibition of NF-kappaB was dependent upon regions of EBNA1 essential for gene transactivation whilst the interaction with the deubiquitinating enzyme, USP7, was entirely dispensable. Furthermore, in agreement with EBNA1 inhibiting p65 NF-kappaB we demonstrate that p65 was exclusively cytoplasmic in 11 out of 11 NPC tumours studied. CONCLUSIONS Inhibition of p65 NF-kappaB in murine and human epidermis results in tissue hyperplasia and the development of squamous cell carcinoma. In line with this, p65 knockout fibroblasts have a transformed phenotype. Inhibition of p65 NF-kappaB by EBNA1 may therefore contribute to the development of NPC by inducing tissue hyperplasia. Furthermore, inhibition of NF-kappaB is employed by viruses as an immune evasion strategy which is also closely linked to oncogenesis during persistent viral infection. Our findings therefore further implicate EBNA1 in playing an important role in the pathogenesis of NPC.
Collapse
Affiliation(s)
- Robert Valentine
- Cancer Research UK Cancer Centre, School of Cancer Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Yarden G, Elfakess R, Gazit K, Dikstein R. Characterization of sINR, a strict version of the Initiator core promoter element. Nucleic Acids Res 2009; 37:4234-46. [PMID: 19443449 PMCID: PMC2715227 DOI: 10.1093/nar/gkp315] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The proximal promoter consists of binding sites for transcription regulators and a core promoter. We identified an overrepresented motif in the proximal promoter of human genes with an Initiator (INR) positional bias. The core of the motif fits the INR consensus but its sequence is more strict and flanked by additional conserved sequences. This strict INR (sINR) is enriched in TATA-less genes that belong to specific functional categories. Analysis of the sINR-containing DHX9 and ATP5F1 genes showed that the entire sINR sequence, including the strict core and the conserved flanking sequences, is important for transcription. A conventional INR sequence could not substitute for DHX9 sINR whereas, sINR could replace a conventional INR. The minimal region required to create the major TSS of the DHX9 promoter includes the sINR and an upstream Sp1 site. In a heterologous context, sINR substituted for the TATA box when positioned downstream to several Sp1 sites. Consistent with that the majority of sINR promoters contain at least one Sp1 site. Thus, sINR is a TATA-less-specific INR that functions in cooperation with Sp1. These findings support the idea that the INR is a family of related core promoter motifs.
Collapse
Affiliation(s)
- Ganit Yarden
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | | | |
Collapse
|
23
|
A translation initiation element specific to mRNAs with very short 5'UTR that also regulates transcription. PLoS One 2008; 3:e3094. [PMID: 18769482 PMCID: PMC2518114 DOI: 10.1371/journal.pone.0003094] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 08/07/2008] [Indexed: 12/18/2022] Open
Abstract
Transcription is controlled by cis regulatory elements, which if localized downstream to the transcriptional start site (TSS), in the 5′UTR, could influence translation as well. However presently there is little evidence for such composite regulatory elements. We have identified by computational analysis an abundant element located downstream to the TSS up to position +30, which controls both transcription and translation. This element has an invariable ATG sequence, which serves as the translation initiation codon in 64% of the genes bearing it. In these genes the initiating AUG is preceded by an extremely short 5′UTR. We show that translation in vitro and in vivo is initiated exclusively from the AUG of this motif, and that the AUG flanking sequences create a strong translation initiation context. This motif is distinguished from the well-known Kozak in its unique ability to direct efficient and accurate translation initiation from mRNAs with a very short 5′UTR. We therefore named it TISU for Translation Initiator of Short 5′UTR. Interestingly, this translation initiation element is also an essential transcription regulatory element of Yin Yang 1. Our characterization of a common transcription and translation element points to a link between mammalian transcription and translation initiation.
Collapse
|