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Tian B, Yang J, Zhao Y, Ivanciuc T, Sun H, Garofalo RP, Brasier AR. BRD4 Couples NF-κB/RelA with Airway Inflammation and the IRF-RIG-I Amplification Loop in Respiratory Syncytial Virus Infection. J Virol 2017; 91:e00007-17. [PMID: 28077651 PMCID: PMC5331805 DOI: 10.1128/jvi.00007-17] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 01/04/2017] [Indexed: 01/09/2023] Open
Abstract
The airway mucosa expresses protective interferon (IFN) and inflammatory cytokines in response to respiratory syncytial virus (RSV) infection. In this study, we examine the role of bromodomain containing 4 (BRD4) in mediating this innate immune response in human small airway epithelial cells. We observe that RSV induces BRD4 to complex with NF-κB/RelA. BRD4 is functionally required for expression of the NF-κB-dependent inflammatory gene regulatory network (GRN), including the IFN response factor 1 (IRF1) and IRF7, which mediate a cross talk pathway for RIG-I upregulation. Mechanistically, BRD4 is required for cyclin-dependent kinase 9 (CDK9) recruitment and phospho-Ser 2 carboxy-terminal domain (CTD) RNA polymerase (Pol) II formation on the promoters of IRF1, IRF7, and RIG-I, producing their enhanced expression by transcriptional elongation. We also find that BRD4 independently regulates CDK9/phospho-Ser 2 CTD RNA Pol II recruitment to the IRF3-dependent IFN-stimulated genes (ISGs). In vivo, poly(I·C)-induced neutrophilia and mucosal chemokine production are blocked by a small-molecule BRD4 bromodomain inhibitor. Similarly, BRD4 inhibition reduces RSV-induced neutrophilia, mucosal CXC chemokine expression, activation of the IRF7-RIG-I autoamplification loop, mucosal IFN expression, and airway obstruction. RSV infection activates BRD4 acetyltransferase activity on histone H3 Lys (K) 122, demonstrating that RSV infection activates BRD4 in vivo These data validate BRD4 as a major effector of RSV-induced inflammation and disease. BRD4 is required for coupling NF-κB to expression of inflammatory genes and the IRF-RIG-I autoamplification pathway and independently facilitates antiviral ISG expression. BRD4 inhibition may be a strategy to reduce exuberant virus-induced mucosal airway inflammation.IMPORTANCE In the United States, 2.1 million children annually require medical attention for RSV infections. A first line of defense is the expression of the innate gene network by infected epithelial cells. Expression of the innate response requires the recruitment of transcriptional elongation factors to rapidly induce innate response genes through an unknown mechanism. We discovered that RSV infection induces a complex of bromodomain containing 4 (BRD4) with NF-κB and cyclin-dependent kinase 9 (CDK9). BRD4 is required for stable CDK9 binding, phospho-Ser 2 RNA Pol II formation, and histone acetyltransferase activity. Inhibition of BRD4 blocks Toll-like receptor 3 (TLR3)-dependent neutrophilia and RSV-induced inflammation, demonstrating its importance in the mucosal innate response in vivo Our study shows that BRD4 plays a central role in inflammation and activation of the IRF7-RIG-I amplification loop vital for mucosal interferon expression. BRD4 inhibition may be a strategy for modulating exuberant mucosal airway inflammation.
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Affiliation(s)
- Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
- Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Jun Yang
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
- Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
- Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA
| | - Teodora Ivanciuc
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Hong Sun
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Roberto P Garofalo
- Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
- Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA
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Coordinate activities of BRD4 and CDK9 in the transcriptional elongation complex are required for TGFβ-induced Nox4 expression and myofibroblast transdifferentiation. Cell Death Dis 2017; 8:e2606. [PMID: 28182006 PMCID: PMC5386453 DOI: 10.1038/cddis.2016.434] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/15/2016] [Accepted: 11/22/2016] [Indexed: 12/19/2022]
Abstract
Transdifferentiation of quiescent dermal fibroblasts to secretory myofibroblasts has a central role in wound healing and pathological scar formation. This myofibroblast transdifferentiation process involves TGFβ-induced de novo synthesis of alpha smooth muscle cell actin (αSMA)+ fibers that enhance contractility as well as increased expression of extracellular matrix (ECM) proteins, including collagen and fibronectin. These processes are mediated upstream by the reactive oxygen species (ROS)-producing enzyme Nox4, whose induction by TGFβ is incompletely understood. In this study, we demonstrate that Nox4 is involved in αSMA+ fiber formation and collagen production in primary human dermal fibroblasts (hDFs) using a small-molecule inhibitor and siRNA-mediated silencing. Furthermore, TGFβ-induced signaling via Smad3 is required for myofibroblast transformation and Nox4 upregulation. Immunoprecipitation-selected reaction monitoring (IP-SRM) assays of the activated Smad3 complex suggest that it couples with the epigenetic reader and transcription co-activator bromodomain and extraterminal (BET) domain containing protein 4 (BRD4) to promote Nox4 transcription. In addition, cyclin-dependent kinase 9 (CDK9), a component of positive transcription elongation factor, binds to BRD4 after TGFβ stimulation and is also required for RNA polymerase II phosphorylation and Nox4 transcription regulation. Surprisingly, BRD4 depletion decreases myofibroblast differentiation but does not affect collagen or fibronectin expression in primary skin fibroblasts, whereas knockdown of CDK9 decreases all myofibroblast genes. We observe enhanced numbers and persistence of myofibroblast formation and TGFβ signaling in hypertrophic scars. BRD4 inhibition reverses hypertrophic skin fibroblast transdifferentiation to myofibroblasts. Our data indicate that BRD4 and CDK9 have independent, coordinated roles in promoting the myofibroblast transition and suggest that inhibition of the Smad3-BRD4 pathway may be a useful strategy to limit hypertrophic scar formation after burn injury.
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Targeting Chromatin Remodeling in Inflammation and Fibrosis. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2016; 107:1-36. [PMID: 28215221 DOI: 10.1016/bs.apcsb.2016.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Mucosal surfaces of the human body are lined by a contiguous epithelial cell surface that forms a barrier to aerosolized pathogens. Specialized pattern recognition receptors detect the presence of viral pathogens and initiate protective host responses by triggering activation of the nuclear factor κB (NFκB)/RelA transcription factor and formation of a complex with the positive transcription elongation factor (P-TEFb)/cyclin-dependent kinase (CDK)9 and Bromodomain-containing protein 4 (BRD4) epigenetic reader. The RelA·BRD4·P-TEFb complex produces acute inflammation by regulating transcriptional elongation, which produces a rapid genomic response by inactive genes maintained in an open chromatin configuration engaged with hypophosphorylated RNA polymerase II. We describe recent studies that have linked prolonged activation of the RelA-BRD4 pathway with the epithelial-mesenchymal transition (EMT) by inducing a core of EMT corepressors, stimulating secretion of growth factors promoting airway fibrosis. The mesenchymal state produces rewiring of the kinome and reprogramming of innate responses toward inflammation. In addition, the core regulator Zinc finger E-box homeodomain 1 (ZEB1) silences the expression of the interferon response factor 1 (IRF1), required for type III IFN expression. This epigenetic silencing is mediated by the Enhancer of Zeste 2 (EZH2) histone methyltransferase. Because of their potential applications in cancer and inflammation, small-molecule inhibitors of NFκB/RelA, CDK9, BRD4, and EZH2 have been the targets of medicinal chemistry efforts. We suggest that disruption of the RelA·BRD4·P-TEFb pathway and EZH2 methyltransferase has important implications for reversing fibrosis and restoring normal mucosal immunity in chronic inflammatory diseases.
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Tino AB, Chitcholtan K, Sykes PH, Garrill A. Resveratrol and acetyl-resveratrol modulate activity of VEGF and IL-8 in ovarian cancer cell aggregates via attenuation of the NF-κB protein. J Ovarian Res 2016; 9:84. [PMID: 27906095 PMCID: PMC5134119 DOI: 10.1186/s13048-016-0293-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/26/2016] [Indexed: 12/14/2022] Open
Abstract
Background Key features of advanced ovarian cancer include metastasis via cell clusters in the abdominal cavity and increased chemoresistance. Resveratrol and derivatives of resveratrol have been shown to have antitumour properties. The purpose of this study was to investigate the effect of resveratrol and acetyl-resveratrol on 3D cell aggregates of ovarian cancer, and establish if NF-κB signalling may be a potential target. Methods Poly-HEMA coated wells were used to produce 3D aggregates of two ovarian cancer cell lines, SKOV-3 and OVCAR-5. The aggregates were exposed to 10, 20 or 30 μM resveratrol or acetyl-resveratrol for 2, 4 or 6 days. Cell growth and metabolism were measured then ELISA, western blot and immunofluorescence were utilised to evaluate VEGF, IL-8 and NF-κB levels. Results Resveratrol and acetyl-resveratrol reduced cell growth and metabolism of SKOV-3 aggregates in a dose- and time-dependent manner. After 6 days all three doses of both compounds inhibited cell growth. This growth inhibition correlated with the attenuated secretion of VEGF and a decrease of NF-κB protein levels. Conversely, the secretion of IL-8 increased with treatment. The effects of the compounds were limited in OVCAR-5 cell clusters. Conclusions The results suggest that resveratrol and its derivative acetyl-resveratrol may inhibit in vitro 3D cell growth of certain subtypes of ovarian cancer, and growth restriction may be associated with the secretion of VEGF under the control of the NF-κB protein.
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Affiliation(s)
- Alexandria B Tino
- Department of Obstetrics and Gynaecology, University of Otago, Christchurch, 2 Riccarton Avenue, Christchurch, 8011, New Zealand
| | - Kenny Chitcholtan
- Obstetrics and Gynaecology Department Christchurch Women's Hospital, Private Bag 4711, Christchurch, 8140, New Zealand.
| | - Peter H Sykes
- Department of Obstetrics and Gynaecology, University of Otago, Christchurch, 2 Riccarton Avenue, Christchurch, 8011, New Zealand
| | - Ashley Garrill
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
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Tian B, Zhao Y, Sun H, Zhang Y, Yang J, Brasier AR. BRD4 mediates NF-κB-dependent epithelial-mesenchymal transition and pulmonary fibrosis via transcriptional elongation. Am J Physiol Lung Cell Mol Physiol 2016; 311:L1183-L1201. [PMID: 27793799 DOI: 10.1152/ajplung.00224.2016] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/25/2016] [Indexed: 02/08/2023] Open
Abstract
Chronic epithelial injury triggers a TGF-β-mediated cellular transition from normal epithelium into a mesenchymal-like state that produces subepithelial fibrosis and airway remodeling. Here we examined how TGF-β induces the mesenchymal cell state and determined its mechanism. We observed that TGF-β stimulation activates an inflammatory gene program controlled by the NF-κB/RelA signaling pathway. In the mesenchymal state, NF-κB-dependent immediate-early genes accumulate euchromatin marks and processive RNA polymerase. This program of immediate-early genes is activated by enhanced expression, nuclear translocation, and activating phosphorylation of the NF-κB/RelA transcription factor on Ser276, mediated by a paracrine signal. Phospho-Ser276 RelA binds to the BRD4/CDK9 transcriptional elongation complex, activating the paused RNA Pol II by phosphorylation on Ser2 in its carboxy-terminal domain. RelA-initiated transcriptional elongation is required for expression of the core epithelial-mesenchymal transition transcriptional regulators SNAI1, TWIST1, and ZEB1 and mesenchymal genes. Finally, we observed that pharmacological inhibition of BRD4 can attenuate experimental lung fibrosis induced by repetitive TGF-β challenge in a mouse model. These data provide a detailed mechanism for how activated NF-κB and BRD4 control epithelial-mesenchymal transition initiation and transcriptional elongation in model airway epithelial cells in vitro and in a murine pulmonary fibrosis model in vivo. Our data validate BRD4 as an in vivo target for the treatment of pulmonary fibrosis associated with inflammation-coupled remodeling in chronic lung diseases.
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Affiliation(s)
- Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; .,Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas.,Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas; and.,Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Hong Sun
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Yueqing Zhang
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Jun Yang
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas.,Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas.,Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas; and.,Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas
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RelA-Mediated BECN1 Expression Is Required for Reactive Oxygen Species-Induced Autophagy in Oral Cancer Cells Exposed to Low-Power Laser Irradiation. PLoS One 2016; 11:e0160586. [PMID: 27632526 PMCID: PMC5025201 DOI: 10.1371/journal.pone.0160586] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 07/21/2016] [Indexed: 12/22/2022] Open
Abstract
Low-power laser irradiation (LPLI) is a non-invasive and safe method for cancer treatment that alters a variety of physiological processes in the cells. Autophagy can play either a cytoprotective role or a detrimental role in cancer cells exposed to stress. The detailed mechanisms of autophagy and its role on cytotoxicity in oral cancer cells exposed to LPLI remain unclear. In this study, we showed that LPLI at 810 nm with energy density 60 J/cm2 increased the number of microtubule associated protein 1 light chain 3 (MAP1LC3) puncta and increased autophagic flux in oral cancer cells. Moreover, reactive oxygen species (ROS) production was induced, which increased RelA transcriptional activity and beclin 1 (BECN1) expression in oral cancer cells irradiated with LPLI. Furthermore, ROS scavenger or knockdown of RelA diminished LPLI-induced BECN1 expression and MAP1LC3-II conversion. In addition, pharmacological and genetic ablation of autophagy significantly enhanced the effects of LPLI-induced apoptosis in oral cancer cells. These results suggest that autophagy may be a resistant mechanism for LPLI-induced apoptosis in oral cancer cells.
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Meng J, Jiang JJ, Atsumi T, Bando H, Okuyama Y, Sabharwal L, Nakagawa I, Higuchi H, Ota M, Okawara M, Ishitani R, Nureki O, Higo D, Arima Y, Ogura H, Kamimura D, Murakami M. Breakpoint Cluster Region–Mediated Inflammation Is Dependent on Casein Kinase II. THE JOURNAL OF IMMUNOLOGY 2016; 197:3111-3119. [DOI: 10.4049/jimmunol.1601082] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/14/2016] [Indexed: 12/25/2022]
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58
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Ajayi BO, Adedara IA, Farombi EO. Benzo(a)pyrene induces oxidative stress, pro-inflammatory cytokines, expression of nuclear factor-kappa B and deregulation of wnt/beta-catenin signaling in colons of BALB/c mice. Food Chem Toxicol 2016; 95:42-51. [DOI: 10.1016/j.fct.2016.06.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 06/14/2016] [Accepted: 06/17/2016] [Indexed: 12/17/2022]
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Zhao Y, Tian B, Sadygov RG, Zhang Y, Brasier AR. Integrative proteomic analysis reveals reprograming tumor necrosis factor signaling in epithelial mesenchymal transition. J Proteomics 2016; 148:126-38. [PMID: 27461979 DOI: 10.1016/j.jprot.2016.07.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/07/2016] [Accepted: 07/12/2016] [Indexed: 12/29/2022]
Abstract
UNLABELLED The airway epithelium is a semi-impermeable barrier whose disruption by growth factor reprogramming is associated with chronic airway diseases of humans. Transforming growth factor beta (TGFβ)-induced epithelial mesenchymal transition (EMT) plays important roles in airway remodeling characteristic of idiopathic lung fibrosis, asthma and chronic obstructive pulmonary disease (COPD). Inflammation of the airways leads to airway injury and tumor necrosis factor alpha (TNFα) plays an important pro-inflammatory role. Little systematic information about the effects of EMT on TNFα signaling is available. Using an in vitro model of TGFβ-induced EMT in primary human small airway epithelial cells (hSAECs), we applied quantitative proteomics and phosphoprotein profiling to understand the molecular mechanism of EMT and the impact of EMT on innate inflammatory responses. We quantified 7925 proteins and 1348 phosphorylation sites by stable isotope labeling with iTRAQ technology. We found that cellular response to TNFα is cell state dependent and the relative TNFα response in mesenchymal state is highly compressed. Combined bioinformatics analyses of proteome and phosphoproteome indicate that the EMT state is associated with reprogramming of kinome, signaling cascade of upstream transcription regulators, phosphor-networks, and NF-κB dependent cell signaling. BIOLOGICAL SIGNIFICANCE Epithelial mesenchymal transition and inflammation have important implications for clinical and physiologic manifestations of chronic airway diseases such as severe asthma, COPD, and lung fibrosis. Little systematic information on the interplay between EMT and innate inflammation is available. This study combined quantitative proteomics and phosphorproteomics approach to obtain systems-level insight into the upstream transcription regulators involved in the TGFβ-induced EMT in primary human small airway epithelial cells and to elucidate how EMT impacts on the TNFα signaling pathways. The proteomics and phosphoproteomics analysis indicates that many signaling pathways involved in TGFβ-induced EMT and EMT has profound reprogramming effects on innate inflammation response.
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Affiliation(s)
- Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, United States; Institute for Translational Sciences, UTMB, Galveston, TX, United States; Sealy Center for Molecular Medicine, UTMB, Galveston, TX, United States.
| | - Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, United States; Institute for Translational Sciences, UTMB, Galveston, TX, United States; Sealy Center for Molecular Medicine, UTMB, Galveston, TX, United States
| | - Rovshan G Sadygov
- Sealy Center for Molecular Medicine, UTMB, Galveston, TX, United States; Department of Biochemistry & Molecular Biology, UTMB, Galveston, TX, United States
| | - Yueqing Zhang
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, United States
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, United States; Institute for Translational Sciences, UTMB, Galveston, TX, United States; Sealy Center for Molecular Medicine, UTMB, Galveston, TX, United States.
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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.
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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
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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.
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Christian F, Smith EL, Carmody RJ. The Regulation of NF-κB Subunits by Phosphorylation. Cells 2016; 5:cells5010012. [PMID: 26999213 PMCID: PMC4810097 DOI: 10.3390/cells5010012] [Citation(s) in RCA: 501] [Impact Index Per Article: 62.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 03/09/2016] [Accepted: 03/14/2016] [Indexed: 12/31/2022] Open
Abstract
The NF-κB transcription factor is the master regulator of the inflammatory response and is essential for the homeostasis of the immune system. NF-κB regulates the transcription of genes that control inflammation, immune cell development, cell cycle, proliferation, and cell death. The fundamental role that NF-κB plays in key physiological processes makes it an important factor in determining health and disease. The importance of NF-κB in tissue homeostasis and immunity has frustrated therapeutic approaches aimed at inhibiting NF-κB activation. However, significant research efforts have revealed the crucial contribution of NF-κB phosphorylation to controlling NF-κB directed transactivation. Importantly, NF-κB phosphorylation controls transcription in a gene-specific manner, offering new opportunities to selectively target NF-κB for therapeutic benefit. This review will focus on the phosphorylation of the NF-κB subunits and the impact on NF-κB function.
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Affiliation(s)
- Frank Christian
- Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
| | - Emma L Smith
- Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
| | - Ruaidhrí J Carmody
- Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
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Choudhary S, Boldogh I, Brasier AR. Inside-Out Signaling Pathways from Nuclear Reactive Oxygen Species Control Pulmonary Innate Immunity. J Innate Immun 2016; 8:143-55. [PMID: 26756522 PMCID: PMC4801701 DOI: 10.1159/000442254] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 11/05/2015] [Accepted: 11/05/2015] [Indexed: 02/05/2023] Open
Abstract
The airway mucosa is responsible for mounting a robust innate immune response (IIR) upon encountering pathogen-associated molecular patterns. The IIR produces protective gene networks that stimulate neighboring epithelia and components of the immune system to trigger adaptive immunity. Little is currently known about how cellular reactive oxygen species (ROS) signaling is produced and cooperates in the IIR. We discuss recent discoveries about 2 nuclear ROS signaling pathways controlling innate immunity. Nuclear ROS oxidize guanine bases to produce mutagenic 8-oxoguanine, a lesion excised by 8-oxoguanine DNA glycosylase1/AP-lyase (OGG1). OGG1 forms a complex with the excised base, inducing its nuclear export. The cytoplasmic OGG1:8-oxoG complex functions as a guanine nucleotide exchange factor, triggering small GTPase signaling and activating phosphorylation of the nuclear factor (NF)x03BA;B/RelA transcription factor to induce immediate early gene expression. In parallel, nuclear ROS are detected by ataxia telangiectasia mutated (ATM), a PI3 kinase activated by ROS, triggering its nuclear export. ATM forms a scaffold with ribosomal S6 kinases, inducing RelA phosphorylation and resulting in transcription-coupled synthesis of type I and type III interferons and CC and CXC chemokines. We propose that ATM and OGG1 are endogenous nuclear ROS sensors that transmit nuclear signals that coordinate with outside-in pattern recognition receptor signaling, regulating the IIR.
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Affiliation(s)
- Sanjeev Choudhary
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Tex., USA
- Department of Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Tex., USA
- Department of Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Tex., USA
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Tex., USA
- Department of Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Tex., USA
- Department of Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Tex., USA
| | - Allan R. Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Tex., USA
- Department of Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Tex., USA
- Department of Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Tex., USA
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Schmitz ML, Kracht M. Cyclin-Dependent Kinases as Coregulators of Inflammatory Gene Expression. Trends Pharmacol Sci 2015; 37:101-113. [PMID: 26719217 DOI: 10.1016/j.tips.2015.10.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 12/22/2022]
Abstract
Cyclin-dependent kinases (CDKs) exert a variety of functions through regulation of the cell cycle and gene expression, thus implicating them in diverse biological processes. Recent studies have deciphered the molecular mechanisms employed by nuclear CDKs to support the expression of inflammatory mediators. Induced transcription of many proinflammatory genes is increased during the G1 phase of the cell cycle in a CDK-dependent manner. This process involves the cytokine-induced recruitment of CDK6 to the nuclear chromatin fraction where it associates with transcription factors of the NF-κB, STAT, and AP-1 families. The ability of CDK6 to trigger the expression of VEGF-A and p16(INK4A) and to recruit the NF-κB subunit p65 to its target sites is largely independent of its kinase function. The involvement of CDKs in proinflammatory gene expression also allows therapeutic targeting of their functions to interfere with tumor-promoting inflammation or chronic inflammatory diseases.
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Affiliation(s)
- M Lienhard Schmitz
- Institute of Biochemistry, Medical Faculty, Friedrichstrasse 24, Justus-Liebig-University, 35392 Giessen, Germany.
| | - Michael Kracht
- Rudolf-Buchheim-Institute for Pharmacology, Medical Faculty, Schubertstrasse 81, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
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Aguilera-Aguirre L, Hosoki K, Bacsi A, Radák Z, Sur S, Hegde ML, Tian B, Saavedra-Molina A, Brasier AR, Ba X, Boldogh I. Whole transcriptome analysis reveals a role for OGG1-initiated DNA repair signaling in airway remodeling. Free Radic Biol Med 2015; 89:20-33. [PMID: 26187872 PMCID: PMC4924473 DOI: 10.1016/j.freeradbiomed.2015.07.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 07/03/2015] [Accepted: 07/07/2015] [Indexed: 12/11/2022]
Abstract
Reactive oxygen species (ROS) generated by environmental exposures, and endogenously as by-products of respiration, oxidatively modify biomolecules including DNA. Accumulation of ROS-induced DNA damage has been implicated in various diseases that involve inflammatory processes, and efficient DNA repair is considered critical in preventing such diseases. One of the most abundant DNA base lesions is 7,8-dihydro-8-oxoguanine (8-oxoG), which is repaired by the 8-oxoguanine DNA glycosylase 1 (OGG1)-initiated base-excision repair (OGG1-BER) pathway. Recent studies have shown that the OGG1-BER by-product 8-oxoG base forms a complex with cytosolic OGG1, activating small GTPases and downstream cell signaling in cultured cells and lungs. This implies that persistent OGG1-BER could result in signaling leading to histological changes in airways. To test this, we mimicked OGG1-BER by repeatedly challenging airways with its repair product 8-oxoG base. Gene expression was analyzed by RNA sequencing (RNA-Seq) and qRT-PCR, and datasets were evaluated by gene ontology and statistical tools. RNA-Seq analysis identified 3252 differentially expressed transcripts (2435 up- and 817 downregulated, ≥ 3-fold change). Among the upregulated transcripts, 2080 mRNAs were identified whose encoded protein products were involved in modulation of the actin family cytoskeleton, extracellular matrix, cell adhesion, cadherin, and cell junctions, affecting biological processes such as tissue development, cell-to-cell adhesion, cell communication, and the immune system. These data are supported by histological observations showing epithelial alterations, subepithelial fibrosis, and collagen deposits in the lungs. These data imply that continuous challenge by the environment and consequent OGG1-BER-driven signaling trigger gene expression consistent with airway remodeling.
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Affiliation(s)
- Leopoldo Aguilera-Aguirre
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Koa Hosoki
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Attila Bacsi
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Zsolt Radák
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Sanjiv Sur
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Center for Molecular Medicine, and, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Muralidhar L Hegde
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Center for Molecular Medicine, and, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alfredo Saavedra-Molina
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Center for Molecular Medicine, and, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Xueqing Ba
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Center for Molecular Medicine, and, University of Texas Medical Branch, Galveston, TX 77555, USA.
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Zeng F, Qin HQ, Xu WJ, Zheng MD, Hu HT, Shui H. Mycophenolic acid inhibits the phosphorylation of nuclear factor‑κB and Akt in renal tubular epithelial cells. Mol Med Rep 2015; 13:560-4. [PMID: 26548367 DOI: 10.3892/mmr.2015.4526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 09/25/2015] [Indexed: 11/06/2022] Open
Abstract
Renal tubulointerstitial injury induced by albumin overload is a critical stage during the progression of renal interstitial fibrosis and progression of chronic renal diseases. Inosine‑5'‑monophosphate dehydrogenase inhibitor mycophenolate mofetil (MMF), a pro‑drug of mycophenolic acid (MPA), is known to attenuate the progression of renal interstitial fibrosis; however, the underlying molecular mechanisms of the anti‑fibrotic effects of derivatives of MMF have not yet been studied. The present study assessed the effects of the MPA on renal tubular epithelial cells. Transforming growth factor beta 1 (TGF‑β1) has been indicated to have a central role in the underlying molecular mechanisms of renal fibrosis; furthermore, nuclear transcription factor‑κB (NF‑κB) is a transcription factor associated with the production of inflammatory cytokines, cell proliferation and apoptosis. In addition, the Akt signaling pathway has important roles in cell proliferation, differentiation, metabolism and apoptosis. The present study subjected the NRK52E rat kidney epithelial‑derived cell line to albumin overload, which resulted in an increase in TGF‑β1 production as well as phosphorylation of Akt and the binding activity of NF‑κB to the promoter region of the TGF‑β1 gene, which was, however, reduced following pre‑incubation of the cells with MPA. In addition, the effects of albumin were partially blocked by Ly294002, a specific inhibitor of Akt. In conclusion, the results of the present study suggested that MPA may exert its anti‑fibrotic effects by inhibiting the upregulation of TGF‑β1 and the activation of NF‑κB following albumin overload, which may be partly dependent on the Akt pathway.
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Affiliation(s)
- Fang Zeng
- Department of Nephrology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Hui-Qun Qin
- Department of Nephrology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Wei-Jia Xu
- Department of Nephrology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Ming-Dan Zheng
- Department of Nephrology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Hong-Tao Hu
- Department of Nephrology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Hua Shui
- Department of Nephrology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430071, P.R. China
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Yang J, Zhao Y, Kalita M, Li X, Jamaluddin M, Tian B, Edeh CB, Wiktorowicz JE, Kudlicki A, Brasier AR. Systematic Determination of Human Cyclin Dependent Kinase (CDK)-9 Interactome Identifies Novel Functions in RNA Splicing Mediated by the DEAD Box (DDX)-5/17 RNA Helicases. Mol Cell Proteomics 2015. [PMID: 26209609 DOI: 10.1074/mcp.m115.049221] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Inducible transcriptional elongation is a rapid, stereotypic mechanism for activating immediate early immune defense genes by the epithelium in response to viral pathogens. Here, the recruitment of a multifunctional complex containing the cyclin dependent kinase 9 (CDK9) triggers the process of transcriptional elongation activating resting RNA polymerase engaged with innate immune response (IIR) genes. To identify additional functional activity of the CDK9 complex, we conducted immunoprecipitation (IP) enrichment-stable isotope labeling LC-MS/MS of the CDK9 complex in unstimulated cells and from cells activated by a synthetic dsRNA, polyinosinic/polycytidylic acid [poly (I:C)]. 245 CDK9 interacting proteins were identified with high confidence in the basal state and 20 proteins in four functional classes were validated by IP-SRM-MS. These data identified that CDK9 interacts with DDX 5/17, a family of ATP-dependent RNA helicases, important in alternative RNA splicing of NFAT5, and mH2A1 mRNA two proteins controlling redox signaling. A direct comparison of the basal versus activated state was performed using stable isotope labeling and validated by IP-SRM-MS. Recruited into the CDK9 interactome in response to poly(I:C) stimulation are HSPB1, DNA dependent kinases, and cytoskeletal myosin proteins that exchange with 60S ribosomal structural proteins. An integrated human CDK9 interactome map was developed containing all known human CDK9- interacting proteins. These data were used to develop a probabilistic global map of CDK9-dependent target genes that predicted two functional states controlling distinct cellular functions, one important in immune and stress responses. The CDK9-DDX5/17 complex was shown to be functionally important by shRNA-mediated knockdown, where differential accumulation of alternatively spliced NFAT5 and mH2A1 transcripts and alterations in downstream redox signaling were seen. The requirement of CDK9 for DDX5 recruitment to NFAT5 and mH2A1 chromatin target was further demonstrated using chromatin immunoprecipitation (ChIP). These data indicate that CDK9 is a dynamic multifunctional enzyme complex mediating not only transcriptional elongation, but also alternative RNA splicing and potentially translational control.
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Affiliation(s)
- Jun Yang
- From the ‡Department of Internal Medicine; §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences
| | - Yingxin Zhao
- From the ‡Department of Internal Medicine; §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences
| | - Mridul Kalita
- §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences
| | - Xueling Li
- ¶Institute for Translational Sciences; ‖Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Mohammad Jamaluddin
- From the ‡Department of Internal Medicine; ¶Institute for Translational Sciences
| | - Bing Tian
- From the ‡Department of Internal Medicine; §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences
| | | | - John E Wiktorowicz
- §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences; ‖Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Andrzej Kudlicki
- §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences; ‖Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Allan R Brasier
- From the ‡Department of Internal Medicine; §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences;
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68
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Tian B, Li X, Kalita M, Widen SG, Yang J, Bhavnani SK, Dang B, Kudlicki A, Sinha M, Kong F, Wood TG, Luxon BA, Brasier AR. Analysis of the TGFβ-induced program in primary airway epithelial cells shows essential role of NF-κB/RelA signaling network in type II epithelial mesenchymal transition. BMC Genomics 2015; 16:529. [PMID: 26187636 PMCID: PMC4506436 DOI: 10.1186/s12864-015-1707-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 06/17/2015] [Indexed: 12/21/2022] Open
Abstract
Background The airway epithelial cell plays a central role in coordinating the pulmonary response to injury and inflammation. Here, transforming growth factor-β (TGFβ) activates gene expression programs to induce stem cell-like properties, inhibit expression of differentiated epithelial adhesion proteins and express mesenchymal contractile proteins. This process is known as epithelial mesenchymal transition (EMT); although much is known about the role of EMT in cellular metastasis in an oncogene-transformed cell, less is known about Type II EMT, that occurring in normal epithelial cells. In this study, we applied next generation sequencing (RNA-Seq) in primary human airway epithelial cells to understand the gene program controlling Type II EMT and how cytokine-induced inflammation modifies it. Results Generalized linear modeling was performed on a two-factor RNA-Seq experiment of 6 treatments of telomerase immortalized human small airway epithelial cells (3 replicates). Using a stringent cut-off, we identified 3,478 differentially expressed genes (DEGs) in response to EMT. Unbiased transcription factor enrichment analysis identified three clusters of EMT regulators, one including SMADs/TP63 and another NF-κB/RelA. Surprisingly, we also observed 527 of the EMT DEGs were also regulated by the TNF-NF-κB/RelA pathway. This Type II EMT program was compared to Type III EMT in TGFβ stimulated A549 alveolar lung cancer cells, revealing significant functional differences. Moreover, we observe that Type II EMT modifies the outcome of the TNF program, reducing IFN signaling and enhancing integrin signaling. We confirmed experimentally that TGFβ-induced the NF-κB/RelA pathway by observing a 2-fold change in NF-κB/RelA nuclear translocation. A small molecule IKK inhibitor blocked TGFβ-induced core transcription factor (SNAIL1, ZEB1 and Twist1) and mesenchymal gene (FN1 and VIM) expression. Conclusions These data indicate that NF-κB/RelA controls a SMAD-independent gene network whose regulation is required for initiation of Type II EMT. Type II EMT dramatically affects the induction and kinetics of TNF-dependent gene networks. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1707-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, USA. .,Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA.
| | - Xueling Li
- Institute for Translational Sciences, UTMB, Galveston, TX, USA. .,Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX, USA.
| | - Mridul Kalita
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, USA.
| | - Steven G Widen
- Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA.
| | - Jun Yang
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, USA.
| | - Suresh K Bhavnani
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, USA. .,Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA. .,Institute for Translational Sciences, UTMB, Galveston, TX, USA.
| | - Bryant Dang
- Institute for Translational Sciences, UTMB, Galveston, TX, USA.
| | - Andrzej Kudlicki
- Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA. .,Institute for Translational Sciences, UTMB, Galveston, TX, USA. .,Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX, USA.
| | - Mala Sinha
- Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA. .,Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX, USA. .,Bioinformatics Program, UTMB, Galveston, TX, USA.
| | - Fanping Kong
- Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA. .,Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX, USA. .,Bioinformatics Program, UTMB, Galveston, TX, USA.
| | - Thomas G Wood
- Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA. .,Institute for Translational Sciences, UTMB, Galveston, TX, USA. .,Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX, USA.
| | - Bruce A Luxon
- Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA. .,Institute for Translational Sciences, UTMB, Galveston, TX, USA. .,Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX, USA. .,Bioinformatics Program, UTMB, Galveston, TX, USA.
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, TX, USA. .,Sealy Center for Molecular Medicine, UTMB, Galveston, TX, USA. .,Institute for Translational Sciences, UTMB, Galveston, TX, USA.
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Singh V, Gupta D, Arora R. NF-kB as a key player in regulation of cellular radiation responses and identification of radiation countermeasures. Discoveries (Craiova) 2015; 3:e35. [PMID: 32309561 PMCID: PMC7159829 DOI: 10.15190/d.2015.27] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Nuclear factor (NF)-κB is a transcription factor that plays significant role in immunity, cellular survival and inhibition of apoptosis, through the induction of genetic networks. Depending on the stimulus and the cell type, the members of NF-κB related family (RelA, c-Rel, RelB, p50, and p52), forms different combinations of homo and hetero-dimers. The activated complexes (Es) translocate into the nucleus and bind to the 10bp κB site of promoter region of target genes in stimulus specific manner. In response to radiation, NF-κB is known to reduce cell death by promoting the expression of anti-apoptotic proteins and activation of cellular antioxidant defense system. Constitutive activation of NF-κB associated genes in tumour cells are known to enhance radiation resistance, whereas deletion in mice results in hypersensitivity to IR-induced GI damage. NF-κB is also known to regulate the production of a wide variety of cytokines and chemokines, which contribute in enhancing cell proliferation and tissue regeneration in various organs, such as the GI crypts stem cells, bone marrow etc., following exposure to IR. Several other cytokines are also known to exert potent pro-inflammatory effects that may contribute to the increase of tissue damage following exposure to ionizing radiation. Till date there are a series of molecules or group of compounds that have been evaluated for their radio-protective potential, and very few have reached clinical trials. The failure or less success of identified agents in humans could be due to their reduced radiation protection efficacy.
In this review we have considered activation of NF-κB as a potential marker in screening of radiation countermeasure agents (RCAs) and cellular radiation responses. Moreover, we have also focused on associated mechanisms of activation of NF-κB signaling and their specified family member activation with respect to stimuli. Furthermore, we have categorized their regulated gene expressions and their function in radiation response or modulation. In addition, we have discussed some recently developed radiation countermeasures in relation to NF-κB activation
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Affiliation(s)
- Vijay Singh
- Division of Radiation Biosciences, Institute of Nuclear Medicine & Allied Sciences, Brig SK Mazumdar Marg, Timarpur, Delhi, India
| | - Damodar Gupta
- Division of Radiation Biosciences, Institute of Nuclear Medicine & Allied Sciences, Brig SK Mazumdar Marg, Timarpur, Delhi, India
| | - Rajesh Arora
- Division of Radiation Biosciences, Institute of Nuclear Medicine & Allied Sciences, Brig SK Mazumdar Marg, Timarpur, Delhi, India
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Jonkers I, Lis JT. Getting up to speed with transcription elongation by RNA polymerase II. Nat Rev Mol Cell Biol 2015; 16:167-77. [PMID: 25693130 PMCID: PMC4782187 DOI: 10.1038/nrm3953] [Citation(s) in RCA: 587] [Impact Index Per Article: 65.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent advances in sequencing techniques that measure nascent transcripts and that reveal the positioning of RNA polymerase II (Pol II) have shown that the pausing of Pol II in promoter-proximal regions and its release to initiate a phase of productive elongation are key steps in transcription regulation. Moreover, after the release of Pol II from the promoter-proximal region, elongation rates are highly dynamic throughout the transcription of a gene, and vary on a gene-by-gene basis. Interestingly, Pol II elongation rates affect co-transcriptional processes such as splicing, termination and genome stability. Increasing numbers of factors and regulatory mechanisms have been associated with the steps of transcription elongation by Pol II, revealing that elongation is a highly complex process. Elongation is thus now recognized as a key phase in the regulation of transcription by Pol II.
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Affiliation(s)
- Iris Jonkers
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, the Netherlands
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, 416 Biotechnology Building, 14853, Ithaca, New York, USA
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Fang L, Choudhary S, Tian B, Boldogh I, Yang C, Ivanciuc T, Ma Y, Garofalo RP, Brasier AR. Ataxia telangiectasia mutated kinase mediates NF-κB serine 276 phosphorylation and interferon expression via the IRF7-RIG-I amplification loop in paramyxovirus infection. J Virol 2015; 89:2628-42. [PMID: 25520509 PMCID: PMC4325710 DOI: 10.1128/jvi.02458-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 12/09/2014] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Respiratory syncytial virus (RSV) is a primary etiological agent of childhood lower respiratory tract disease. Molecular patterns induced by active infection trigger a coordinated retinoic acid-inducible gene I (RIG-I)-Toll-like receptor (TLR) signaling response to induce inflammatory cytokines and antiviral mucosal interferons. Recently, we discovered a nuclear oxidative stress-sensitive pathway mediated by the DNA damage response protein, ataxia telangiectasia mutated (ATM), in cytokine-induced NF-κB/RelA Ser 276 phosphorylation. Here we observe that ATM silencing results in enhanced single-strand RNA (ssRNA) replication of RSVand Sendai virus, due to decreased expression and secretion of type I and III interferons (IFNs), despite maintenance of IFN regulatory factor 3 (IRF3)-dependent IFN-stimulated genes (ISGs). In addition to enhanced oxidative stress, RSV replication enhances foci of phosphorylated histone 2AX variant (γH2AX), Ser 1981 phosphorylation of ATM, and IKKγ/NEMO-dependent ATM nuclear export, indicating activation of the DNA damage response. ATM-deficient cells show defective RSV-induced mitogen and stress-activated kinase 1 (MSK-1) Ser 376 phosphorylation and reduced RelA Ser 276 phosphorylation, whose formation is required for IRF7 expression. We observe that RelA inducibly binds the native IFN regulatory factor 7 (IRF7) promoter in an ATM-dependent manner, and IRF7 inducibly binds to the endogenous retinoic acid-inducible gene I (RIG-I) promoter. Ectopic IRF7 expression restores RIG-I expression and type I/III IFN expression in ATM-silenced cells. We conclude that paramyxoviruses trigger the DNA damage response, a pathway required for MSK1 activation of phospho Ser 276 RelA formation to trigger the IRF7-RIG-I amplification loop necessary for mucosal IFN production. These data provide the molecular pathogenesis for defects in the cellular innate immunity of patients with homozygous ATM mutations. IMPORTANCE RNA virus infections trigger cellular response pathways to limit spread to adjacent tissues. This "innate immune response" is mediated by germ line-encoded pattern recognition receptors that trigger activation of two, largely independent, intracellular NF-κB and IRF3 transcription factors. Downstream, expression of protective antiviral interferons is amplified by positive-feedback loops mediated by inducible interferon regulatory factors (IRFs) and retinoic acid inducible gene (RIG-I). Our results indicate that a nuclear oxidative stress- and DNA damage-sensing factor, ATM, is required to mediate a cross talk pathway between NF-κB and IRF7 through mediating phosphorylation of NF-κB. Our studies provide further information about the defects in cellular and innate immunity in patients with inherited ATM mutations.
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Affiliation(s)
- Ling Fang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Sanjeev Choudhary
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA
| | - Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA
| | - Istvan Boldogh
- Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Chunying Yang
- Department of Radiation Oncology, Houston Methodist Research Institute, Weill Cornell University, Houston, Texas, USA
| | - Teodora Ivanciuc
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Yinghong Ma
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Roberto P Garofalo
- Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA
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Reversal of radiocontrast medium toxicity in human renal proximal tubular cells by white grape juice extract. Chem Biol Interact 2015; 229:17-25. [PMID: 25603236 DOI: 10.1016/j.cbi.2014.12.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/16/2014] [Accepted: 12/22/2014] [Indexed: 01/18/2023]
Abstract
Radiocontrast media (RCM)-induced nephrotoxicity (CIN) is a major clinical problem accounting for 12% of all hospital-acquired cases of acute kidney injury. The pathophysiology of CIN is not well understood, but direct toxic effects on renal cells have been postulated as contributing to CIN. We have investigated the effect of a white grape (Vitis vinifera) juice extract (WGJe) on human renal proximal tubular (HK-2) cells treated with the radiocontrast medium (RCM) sodium diatrizoate. WGJe caused an increase in phosphorylation of the prosurvival kinases Akt and ERK1/2 in HK-2 cells. Treatment of HK-2 cells with 75 mgI/ml sodium diatrizoate for 2.5h and then further incubation (for 27.5h) after removal of the RCM caused a drastic decrease in cell viability. However, pre-treatment with WGJe, prior to incubation with diatrizoate, dramatically improved cell viability. Analysis of key signaling molecules by Western blotting showed that diatrizoate caused a drastic decrease in phosphorylation of Akt (Ser473), FOXO1 (Thr24) and FOXO3a (Thr32) during the initial 2.5h incubation period, and WGJe pre-treatment caused a reversal of these effects. Further analysis by Western blotting of samples from HK-2 cells cultured for longer periods of time (for up to 27.5h after an initial 2.5h exposure to diatrizoate with or without WGJe pre-treatment) showed that WGJe pre-treatment caused a negative effect on phosphorylation of p38, NF-κB (Ser276) and pERK1/2 whilst having a positive effect on the phosphorylation of Akt, FOXO1/FOXO3a and maintained levels of Pim-1 kinase. WGJe may alleviate RCM toxicity through modulation of signaling molecules that are known to be involved in cell death and cell survival and its possible beneficial effects should be further investigated.
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Fu W, Farache J, Clardy SM, Hattori K, Mander P, Lee K, Rioja I, Weissleder R, Prinjha RK, Benoist C, Mathis D. Epigenetic modulation of type-1 diabetes via a dual effect on pancreatic macrophages and β cells. eLife 2014; 3:e04631. [PMID: 25407682 PMCID: PMC4270084 DOI: 10.7554/elife.04631] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 11/19/2014] [Indexed: 12/13/2022] Open
Abstract
Epigenetic modifiers are an emerging class of anti-tumor drugs, potent in multiple cancer contexts. Their effect on spontaneously developing autoimmune diseases has been little explored. We report that a short treatment with I-BET151, a small-molecule inhibitor of a family of bromodomain-containing transcriptional regulators, irreversibly suppressed development of type-1 diabetes in NOD mice. The inhibitor could prevent or clear insulitis, but had minimal influence on the transcriptomes of infiltrating and circulating T cells. Rather, it induced pancreatic macrophages to adopt an anti-inflammatory phenotype, impacting the NF-κB pathway in particular. I-BET151 also elicited regeneration of islet β-cells, inducing proliferation and expression of genes encoding transcription factors key to β-cell differentiation/function. The effect on β cells did not require T cell infiltration of the islets. Thus, treatment with I-BET151 achieves a 'combination therapy' currently advocated by many diabetes investigators, operating by a novel mechanism that coincidentally dampens islet inflammation and enhances β-cell regeneration.
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Affiliation(s)
- Wenxian Fu
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
| | - Julia Farache
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
| | - Susan M Clardy
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, United States
| | - Kimie Hattori
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
| | - Palwinder Mander
- Epinova DPU, Immuno-Inflammation Therapy Area, Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
| | - Kevin Lee
- Epinova DPU, Immuno-Inflammation Therapy Area, Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
| | - Inmaculada Rioja
- Epinova DPU, Immuno-Inflammation Therapy Area, Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
| | - Ralph Weissleder
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, United States
| | - Rab K Prinjha
- Epinova DPU, Immuno-Inflammation Therapy Area, Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
| | - Christophe Benoist
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
| | - Diane Mathis
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
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Rojo AI, McBean G, Cindric M, Egea J, López MG, Rada P, Zarkovic N, Cuadrado A. Redox control of microglial function: molecular mechanisms and functional significance. Antioxid Redox Signal 2014; 21:1766-801. [PMID: 24597893 PMCID: PMC4186766 DOI: 10.1089/ars.2013.5745] [Citation(s) in RCA: 234] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neurodegenerative diseases are characterized by chronic microglial over-activation and oxidative stress. It is now beginning to be recognized that reactive oxygen species (ROS) produced by either microglia or the surrounding environment not only impact neurons but also modulate microglial activity. In this review, we first analyze the hallmarks of pro-inflammatory and anti-inflammatory phenotypes of microglia and their regulation by ROS. Then, we consider the production of reactive oxygen and nitrogen species by NADPH oxidases and nitric oxide synthases and the new findings that also indicate an essential role of glutathione (γ-glutamyl-l-cysteinylglycine) in redox homeostasis of microglia. The effect of oxidant modification of macromolecules on signaling is analyzed at the level of oxidized lipid by-products and sulfhydryl modification of microglial proteins. Redox signaling has a profound impact on two transcription factors that modulate microglial fate, nuclear factor kappa-light-chain-enhancer of activated B cells, and nuclear factor (erythroid-derived 2)-like 2, master regulators of the pro-inflammatory and antioxidant responses of microglia, respectively. The relevance of these proteins in the modulation of microglial activity and the interplay between them will be evaluated. Finally, the relevance of ROS in altering blood brain barrier permeability is discussed. Recent examples of the importance of these findings in the onset or progression of neurodegenerative diseases are also discussed. This review should provide a profound insight into the role of redox homeostasis in microglial activity and help in the identification of new promising targets to control neuroinflammation through redox control of the brain.
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Affiliation(s)
- Ana I Rojo
- 1 Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Madrid, Spain
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75
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Aguilera-Aguirre L, Bacsi A, Radak Z, Hazra TK, Mitra S, Sur S, Brasier AR, Ba X, Boldogh I. Innate inflammation induced by the 8-oxoguanine DNA glycosylase-1-KRAS-NF-κB pathway. THE JOURNAL OF IMMUNOLOGY 2014; 193:4643-53. [PMID: 25267977 DOI: 10.4049/jimmunol.1401625] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
8-Oxoguanine-DNA glycosylase-1 (OGG1) is the primary enzyme for repairing 7,8-dihydro-8-oxoguanine (8-oxoG) via the DNA base excision repair pathway (OGG1-BER). Accumulation of 8-oxoG in the genomic DNA leads to genetic instability and carcinogenesis and is thought to contribute to the worsening of various inflammatory and disease processes. However, the disease mechanism is unknown. In this study, we proposed that the mechanistic link between OGG1-BER and proinflammatory gene expression is OGG1's guanine nucleotide exchange factor activity, acquired after interaction with the 8-oxoG base and consequent activation of the small GTPase RAS. To test this hypothesis, we used BALB/c mice expressing or deficient in OGG1 in their airway epithelium and various molecular biological approaches, including active RAS pulldown, reporter and Comet assays, small interfering RNA-mediated depletion of gene expression, quantitative RT-PCR, and immunoblotting. We report that the OGG1-initiated repair of oxidatively damaged DNA is a prerequisite for GDP → GTP exchange, KRAS-GTP-driven signaling via MAP kinases and PI3 kinases and mitogen-stress-related kinase-1 for NF-κB activation, proinflammatory chemokine/cytokine expression, and inflammatory cell recruitment to the airways. Mice deficient in OGG1-BER showed significantly decreased immune responses, whereas a lack of other Nei-like DNA glycosylases (i.e., NEIL1 and NEIL2) had no significant effect. These data unveil a previously unidentified role of OGG1-driven DNA BER in the generation of endogenous signals for inflammation in the innate signaling pathway.
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Affiliation(s)
| | - Attila Bacsi
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555
| | - Zsolt Radak
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555
| | - Tapas K Hazra
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555; Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555; and
| | - Sankar Mitra
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
| | - Sanjiv Sur
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555; and Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, TX 77555
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555; and Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, TX 77555
| | - Xueqing Ba
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555; Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, TX 77555
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76
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Phenyl-1-Pyridin-2yl-ethanone-based iron chelators increase IκB-α expression, modulate CDK2 and CDK9 activities, and inhibit HIV-1 transcription. Antimicrob Agents Chemother 2014; 58:6558-71. [PMID: 25155598 DOI: 10.1128/aac.02918-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
HIV-1 transcription is activated by the Tat protein, which recruits CDK9/cyclin T1 to the HIV-1 promoter. CDK9 is phosphorylated by CDK2, which facilitates formation of the high-molecular-weight positive transcription elongation factor b (P-TEFb) complex. We previously showed that chelation of intracellular iron inhibits CDK2 and CDK9 activities and suppresses HIV-1 transcription, but the mechanism of the inhibition was not understood. In the present study, we tested a set of novel iron chelators for the ability to inhibit HIV-1 transcription and elucidated their mechanism of action. Novel phenyl-1-pyridin-2yl-ethanone (PPY)-based iron chelators were synthesized and examined for their effects on cellular iron, HIV-1 inhibition, and cytotoxicity. Activities of CDK2 and CDK9, expression of CDK9-dependent and CDK2-inhibitory mRNAs, NF-κB expression, and HIV-1- and NF-κB-dependent transcription were determined. PPY-based iron chelators significantly inhibited HIV-1, with minimal cytotoxicity, in cultured and primary cells chronically or acutely infected with HIV-1 subtype B, but they had less of an effect on HIV-1 subtype C. Iron chelators upregulated the expression of IκB-α, with increased accumulation of cytoplasmic NF-κB. The iron chelators inhibited CDK2 activity and reduced the amount of CDK9/cyclin T1 in the large P-TEFb complex. Iron chelators reduced HIV-1 Gag and Env mRNA synthesis but had no effect on HIV-1 reverse transcription. In addition, iron chelators moderately inhibited basal HIV-1 transcription, equally affecting HIV-1 and Sp1- or NF-κB-driven transcription. By virtue of their involvement in targeting several key steps in HIV-1 transcription, these novel iron chelators have the potential for the development of new therapeutics for the treatment of HIV-1 infection.
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77
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Tumor necrosis factor-α-induced nuclear factor-kappaB activation in human cardiomyocytes is mediated by NADPH oxidase. J Physiol Biochem 2014; 70:769-79. [PMID: 25059721 DOI: 10.1007/s13105-014-0345-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 07/01/2014] [Indexed: 12/18/2022]
Abstract
An elevated level of tumor necrosis factor (TNF)-α is implicated in several cardiovascular diseases including heart failure. Numerous reports have demonstrated that TNF-α activates nuclear factor (NF)-kappaB, resulting in the upregulation of several genes that regulate inflammation, proliferation, and apoptosis of cardiomyocytes. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, a major source of reactive oxygen species (ROS), is also activated by TNF-α and plays a crucial role in redox-sensitive signaling pathways. The present study investigated whether NADPH oxidase mediates TNF-α-induced NF-kappaB activation and NF-kappaB-mediated gene expression. Human cardiomyocytes were treated with recombinant TNF-α with or without pretreatment with diphenyleneiodonium (DPI) and apocynin, inhibitors of NADPH oxidase. TNF-α-induced ROS production was measured using 5-(and-6)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate assay. TNF-α-induced NF-kappaB activation was also examined using immunoblot; NF-kappaB binding to its binding motif was determined using a Cignal reporter luciferase assay and an electrophoretic mobility shift assay. TNF-α-induced upregulation of interleukin (IL)-1β and vascular cell adhesion molecule (VCAM)-1 was investigated using real-time PCR and immunoblot. TNF-α-induced ROS production in cardiomyocytes was mediated by NADPH oxidase. Phosphorylation of IKK-α/β and p65, degradation of IkappaBα, binding of NF-kappaB to its binding motif, and upregulation of IL-1β and VCAM-1 induced by TNF-α were significantly attenuated by treatment with DPI and apocynin. Collectively, these findings demonstrate that NADPH oxidase plays a role in regulation of TNF-α-induced NF-kappaB activation and upregulation of proinflammatory cytokines, IL-1β and VCAM-1, in human cardiomyocytes.
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78
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Andreucci M, Faga T, Russo D, Bertucci B, Tamburrini O, Pisani A, Sabbatini M, Fuiano G, Michael A. Differential activation of signaling pathways by low-osmolar and iso-osmolar radiocontrast agents in human renal tubular cells. J Cell Biochem 2014; 115:281-9. [PMID: 24023012 DOI: 10.1002/jcb.24662] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 08/19/2013] [Indexed: 11/10/2022]
Abstract
Radiocontrast media (RCM)-induced nephrotoxicity (CIN) is a major clinical problem accounting for 12% of all hospital-acquired cases of acute kidney injury (AKI). The pathophysiology of AKI due to RCM is not well understood, but direct toxic effects on renal cells have been postulated as contributing to CIN. It is believed that iso-osmolar RCM (IOCM) are less nephrotoxic than low-osmolar RCM (LOCM) but clinical data have been controversial. We have investigated the intracellular signaling pathways that may be affected by the LOCM iomeprol (IOM) and the IOCM iodixanol (IOD). Both IOM and IOD caused a dramatic decrease in phosphorylation of the kinase Akt at Ser473 and Thr308 in human renal tubular (HK-2) cells, with IOM having a greater effect; IOM also caused a greater decrease in cell viability. IOM also had a greater effect on phosphorylation of p38 MAP kinases, JNKs, and NF-kB (Ser276), and caused a marked decrease in the phosphorylation of forkhead box O3a (FOXO3a) and signal transducer and activator of transcription 3 (STAT3). However, IOD caused a greater decrease in the phosphorylation of mTOR (Ser2448) and phospho-ERK 1/2 while both RCM caused a similar decrease in the phosphorylation of phospho-p70S6 kinase (Ser371). In vivo studies showed that both IOM and IOD caused a significant decrease in both pAkt (Ser473) and pERK 1/2 in rat kidneys. Our study gives an insight into the possible mechanism of toxicity of RCM via their action on intracellular signaling pathways and may help in developing pharmacological interventions for their side-effects.
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Affiliation(s)
- Michele Andreucci
- Chair of Nephrology, Department of Health Sciences, "Magna Graecia" University, Catanzaro, I-88100, Italy
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79
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Fang L, Choudhary S, Zhao Y, Edeh CB, Yang C, Boldogh I, Brasier AR. ATM regulates NF-κB-dependent immediate-early genes via RelA Ser 276 phosphorylation coupled to CDK9 promoter recruitment. Nucleic Acids Res 2014; 42:8416-32. [PMID: 24957606 PMCID: PMC4117761 DOI: 10.1093/nar/gku529] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ataxia-telangiectasia mutated (ATM), a member of the phosphatidylinositol 3 kinase-like kinase family, is a master regulator of the double strand DNA break-repair pathway after genotoxic stress. Here, we found ATM serves as an essential regulator of TNF-induced NF-kB pathway. We observed that TNF exposure of cells rapidly induced DNA double strand breaks and activates ATM. TNF-induced ROS promote nuclear IKKγ association with ubiquitin and its complex formation with ATM for nuclear export. Activated cytoplasmic ATM is involved in the selective recruitment of the E3-ubiquitin ligase β-TrCP to phospho-IκBα proteosomal degradation. Importantly, ATM binds and activates the catalytic subunit of protein kinase A (PKAc), ribosmal S6 kinase that controls RelA Ser 276 phosphorylation. In ATM knockdown cells, TNF-induced RelA Ser 276 phosphorylation is significantly decreased. We further observed decreased binding and recruitment of the transcriptional elongation complex containing cyclin dependent kinase-9 (CDK9; a kinase necessary for triggering transcriptional elongation) to promoters of NF-κB-dependent immediate-early cytokine genes, in ATM knockdown cells. We conclude that ATM is a nuclear damage-response signal modulator of TNF-induced NF-κB activation that plays a key scaffolding role in IκBα degradation and RelA Ser 276 phosphorylation. Our study provides a mechanistic explanation of decreased innate immune response associated with A-T mutation.
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Affiliation(s)
- Ling Fang
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX 77555, USA
| | - Sanjeev Choudhary
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Chukwudi B Edeh
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA
| | - Chunying Yang
- Department of Radiation Oncology, Houston Methodist Research Institute, Weill Cornell University, Houston, TX 77030, USA
| | - Istvan Boldogh
- Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Department of Microbiology and Immunology, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
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80
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Bertolusso R, Tian B, Zhao Y, Vergara L, Sabree A, Iwanaszko M, Lipniacki T, Brasier AR, Kimmel M. Dynamic cross talk model of the epithelial innate immune response to double-stranded RNA stimulation: coordinated dynamics emerging from cell-level noise. PLoS One 2014; 9:e93396. [PMID: 24710104 PMCID: PMC3977818 DOI: 10.1371/journal.pone.0093396] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 03/04/2014] [Indexed: 01/01/2023] Open
Abstract
We present an integrated dynamical cross-talk model of the epithelial innate immune response (IIR) incorporating RIG-I and TLR3 as the two major pattern recognition receptors (PRR) converging on the RelA and IRF3 transcriptional effectors. bioPN simulations reproduce biologically relevant gene-and protein abundance measurements in response to time course, gene silencing and dose-response perturbations both at the population and single cell level. Our computational predictions suggest that RelA and IRF3 are under auto- and cross-regulation. We predict, and confirm experimentally, that RIG-I mRNA expression is controlled by IRF7. We also predict the existence of a TLR3-dependent, IRF3-independent transcription factor (or factors) that control(s) expression of MAVS, IRF3 and members of the IKK family. Our model confirms the observed dsRNA dose-dependence of oscillatory patterns in single cells, with periods of 1-3 hr. Model fitting to time series, matched by knockdown data suggests that the NF-κB module operates in a different regime (with different coefficient values) than in the TNFα-stimulation experiments. In future studies, this model will serve as a foundation for identification of virus-encoded IIR antagonists and examination of stochastic effects of viral replication. Our model generates simulated time series, which reproduce the noisy oscillatory patterns of activity (with 1-3 hour period) observed in individual cells. Our work supports the hypothesis that the IIR is a phenomenon that emerged by evolution despite highly variable responses at an individual cell level.
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Affiliation(s)
- Roberto Bertolusso
- Department of Statistics, Rice University, Houston, Texas, United States of America
| | - Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, Texas, United States of America
| | - Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, Texas, United States of America
- Sealy Center for Molecular Medicine, UTMB, Galveston, Texas, United States of America
- Institute for Translational Sciences, UTMB, Galveston, Texas, United States of America
| | - Leoncio Vergara
- Center for Biomedical Engineering, UTMB, Galveston, Texas, United States of America
| | - Aqeeb Sabree
- Department of Statistics, Rice University, Houston, Texas, United States of America
| | - Marta Iwanaszko
- Systems Engineering Group, Silesian University of Technology, Gliwice, Poland
| | - Tomasz Lipniacki
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Allan R. Brasier
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), Galveston, Texas, United States of America
- Sealy Center for Molecular Medicine, UTMB, Galveston, Texas, United States of America
- Institute for Translational Sciences, UTMB, Galveston, Texas, United States of America
| | - Marek Kimmel
- Department of Statistics, Rice University, Houston, Texas, United States of America
- Systems Engineering Group, Silesian University of Technology, Gliwice, Poland
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81
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Michael A, Faga T, Pisani A, Riccio E, Bramanti P, Sabbatini M, Navarra M, Andreucci M. Molecular mechanisms of renal cellular nephrotoxicity due to radiocontrast media. BIOMED RESEARCH INTERNATIONAL 2014; 2014:249810. [PMID: 24745009 PMCID: PMC3976916 DOI: 10.1155/2014/249810] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/09/2013] [Accepted: 12/24/2013] [Indexed: 11/29/2022]
Abstract
Modern iodinated radiocontrast media are all based on the triiodinated benzene ring with various chemical modifications having been made over the last few decades in order to reduce their toxicity. However, CIN remains a problem especially in patients with pre-existing renal failure. In vitro studies have demonstrated that all RCM are cytotoxic. RCM administration in vivo may lead to a decrease in renal medullary oxygenation leading to the generation of reactive oxygen species that may cause harmful effects to renal tissue. In addition, endothelin and adenosine release and decreased nitric oxide levels may worsen the hypoxic milieu. In vitro cell culture studies together with sparse in vivo rat model data have shown that important cell signalling pathways are affected by RCM. In particular, the prosurvival and proproliferative kinases Akt and ERK1/2 have been shown to be dephosphorylated (deactivated), whilst proinflammatory/cell death molecules such as the p38 and JNK kinases and the transcription factor NF- κ B may be activated by RCM, accompanied by activation of apoptotic mediators such as caspases. Increasing our knowledge of the mechanisms of RCM action may help to develop future therapies for CIN.
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Affiliation(s)
- Ashour Michael
- Department of Health Sciences, Nephrology Unit, “Magna Graecia” University, I-88100 Catanzaro, Italy
| | - Teresa Faga
- Department of Health Sciences, Nephrology Unit, “Magna Graecia” University, I-88100 Catanzaro, Italy
| | - Antonio Pisani
- Department of Nephrology, “Federico II” University, I-80131 Naples, Italy
| | - Eleonora Riccio
- Department of Nephrology, “Federico II” University, I-80131 Naples, Italy
| | | | - Massimo Sabbatini
- Department of Nephrology, “Federico II” University, I-80131 Naples, Italy
| | - Michele Navarra
- Department of Drug Sciences and Health Products, University of Messina, I-98168 Messina, Italy
| | - Michele Andreucci
- Department of Health Sciences, Nephrology Unit, “Magna Graecia” University, I-88100 Catanzaro, Italy
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82
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Johnson J, Shi Z, Liu Y, Stack MS. Inhibitors of NF-kappaB reverse cellular invasion and target gene upregulation in an experimental model of aggressive oral squamous cell carcinoma. Oral Oncol 2014; 50:468-77. [PMID: 24582884 DOI: 10.1016/j.oraloncology.2014.02.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 01/28/2014] [Accepted: 02/05/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND Oral squamous cell carcinoma (OSCC) is diagnosed in 640,000 patients yearly with a poor (50%) 5-year survival rate that has not changed appreciably in decades. PAITENTS AND METHODS To investigate molecular changes that drive OSCC progression, cDNA microarray analysis was performed using human OSCC cells that form aggressive poorly differentiated tumors (SCC25-PD) in a murine orthotopic xenograft model compared to cells that produce well-differentiated tumors (SCC25-WD). RESULTS As this analysis revealed that 59 upregulated genes were NF-κB target genes, the role of NF-κB activation in alteration of the transcriptional profile was evaluated. The mRNA and protein upregulation of a panel NF-κB target genes was validated by real-time qPCR and immunohistochemistry. Additionally, nuclear translocation of RelA was greatly increased in SCC25-PD, increased nuclear RelA was observed in oral tumors initiated with SCC25-PD compared with tumors initiated by SCC25-WD, and nuclear RelA correlated with stage of disease on two human OSCC tissue microarrays. Treatment of SCC25-PD cells with the IKKβ-inhibitor sc-514, that effectively prevents RelA phosphorylation on Ser 536, reversed nuclear-translocation of RelA and strongly inhibited NF-κB gene activation. Furthermore, blocking the phosphorylation of RelA using the MSK1/2 inhibitor SB 747651A significantly reduced the mRNA upregulation of a subset of target genes. Treatment with sc-514 or SB747651A markedly diminished cellular invasiveness. CONCLUSIONS These studies support a model wherein NF-κB is constitutively active in aggressive OSCC, while blocking the NF-κB pathway reduces NF-κB target gene upregulation and cellular invasiveness.
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Affiliation(s)
- Jeff Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, South Bend, IN 46617, United States; Harper Cancer Research Institute, University of Notre Dame, South Bend, IN 46617, United States
| | - Zonggao Shi
- Department of Chemistry and Biochemistry, University of Notre Dame, South Bend, IN 46617, United States; Harper Cancer Research Institute, University of Notre Dame, South Bend, IN 46617, United States
| | - Yueying Liu
- Department of Chemistry and Biochemistry, University of Notre Dame, South Bend, IN 46617, United States; Harper Cancer Research Institute, University of Notre Dame, South Bend, IN 46617, United States
| | - M Sharon Stack
- Department of Chemistry and Biochemistry, University of Notre Dame, South Bend, IN 46617, United States; Harper Cancer Research Institute, University of Notre Dame, South Bend, IN 46617, United States.
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83
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Ba X, Bacsi A, Luo J, Aguilera-Aguirre L, Zeng X, Radak Z, Brasier AR, Boldogh I. 8-oxoguanine DNA glycosylase-1 augments proinflammatory gene expression by facilitating the recruitment of site-specific transcription factors. THE JOURNAL OF IMMUNOLOGY 2014; 192:2384-94. [PMID: 24489103 DOI: 10.4049/jimmunol.1302472] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Among the insidious DNA base lesions, 8-oxo-7,8-dihydroguanine (8-oxoG) is one of the most abundant, a lesion that arises through the attack by reactive oxygen species on guanine, especially when located in cis-regulatory elements. 8-oxoG is repaired by the 8-oxoguanine glycosylase 1 (OGG1)-initiated DNA base excision repair pathway. In this study, we investigated whether 8-oxoG repair by OGG1 in promoter regions is compatible with a prompt gene expression and a host innate immune response. For this purpose, we used a mouse model of airway inflammation, supplemented with cell cultures, chromatin immunoprecipitation, small interfering RNA knockdown, real-time PCR, and comet and reporter transcription assays. Our data show that exposure of cells to TNF-α altered cellular redox, increased the 8-oxoG level in DNA, recruited OGG1 to promoter sequences, and transiently inhibited base excision repair of 8-oxoG. Promoter-associated OGG1 then enhanced NF-κB/RelA binding to cis-elements and facilitated recruitment of specificity protein 1, transcription initiation factor II-D, and p-RNA polymerase II, resulting in the rapid expression of chemokines/cytokines and inflammatory cell accumulation in mouse airways. Small interfering RNA depletion of OGG1 or prevention of guanine oxidation significantly decreased TNF-α-induced inflammatory responses. Taken together, these results show that nonproductive binding of OGG1 to 8-oxoG in promoter sequences could be an epigenetic mechanism to modulate gene expression for a prompt innate immune response.
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Affiliation(s)
- Xueqing Ba
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555
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84
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Kalita M, Tian B, Gao B, Choudhary S, Wood TG, Carmical JR, Boldogh I, Mitra S, Minna JD, Brasier AR. Systems approaches to modeling chronic mucosal inflammation. BIOMED RESEARCH INTERNATIONAL 2013; 2013:505864. [PMID: 24228254 PMCID: PMC3818818 DOI: 10.1155/2013/505864] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/08/2013] [Accepted: 08/09/2013] [Indexed: 12/27/2022]
Abstract
The respiratory mucosa is a major coordinator of the inflammatory response in chronic airway diseases, including asthma and chronic obstructive pulmonary disease (COPD). Signals produced by the chronic inflammatory process induce epithelial mesenchymal transition (EMT) that dramatically alters the epithelial cell phenotype. The effects of EMT on epigenetic reprogramming and the activation of transcriptional networks are known, its effects on the innate inflammatory response are underexplored. We used a multiplex gene expression profiling platform to investigate the perturbations of the innate pathways induced by TGF β in a primary airway epithelial cell model of EMT. EMT had dramatic effects on the induction of the innate pathway and the coupling interval of the canonical and noncanonical NF- κ B pathways. Simulation experiments demonstrate that rapid, coordinated cap-independent translation of TRAF-1 and NF- κ B2 is required to reduce the noncanonical pathway coupling interval. Experiments using amantadine confirmed the prediction that TRAF-1 and NF- κ B2/p100 production is mediated by an IRES-dependent mechanism. These data indicate that the epigenetic changes produced by EMT induce dynamic state changes of the innate signaling pathway. Further applications of systems approaches will provide understanding of this complex phenotype through deterministic modeling and multidimensional (genomic and proteomic) profiling.
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Affiliation(s)
- Mridul Kalita
- Sealy Center for Molecular Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Bing Tian
- Department of Internal Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Boning Gao
- Hamon Center for Therapeutic Oncology Research, Department of Internal Medicine Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sanjeev Choudhary
- Sealy Center for Molecular Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Department of Internal Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Institute for Translational Sciences, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Thomas G. Wood
- Sealy Center for Molecular Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Institute for Translational Sciences, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Departments of Biochemistry and Molecular Biology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Joseph R. Carmical
- Departments of Biochemistry and Molecular Biology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Istvan Boldogh
- Sealy Center for Molecular Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Microbiology and Immunology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Sankar Mitra
- Sealy Center for Molecular Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Departments of Biochemistry and Molecular Biology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - John D. Minna
- Hamon Center for Therapeutic Oncology Research, Department of Internal Medicine Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Allan R. Brasier
- Sealy Center for Molecular Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Department of Internal Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Institute for Translational Sciences, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
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85
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Abstract
At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.
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Affiliation(s)
- Paul N Hopkins
- Cardiovascular Genetics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.
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86
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Brasier AR. Identification of innate immune response endotypes in asthma: implications for personalized medicine. Curr Allergy Asthma Rep 2013; 13:462-8. [PMID: 23793609 PMCID: PMC3778047 DOI: 10.1007/s11882-013-0363-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Asthma is an idiopathic disease characterized by episodic inflammation and reversible airway obstruction triggered by exposure to environmental agents. Because this disease is heterogeneous in onset, exacerbations, inflammatory states, and response to therapy, there is intense interest in developing personalized approaches to its management. Of focus in this review, the recognition that a component of the pathophysiology of asthma is mediated by inflammation has implications for understanding its etiology and individualizing its therapy. Despite understanding how Th2 polarization mediates asthma exacerbations by aeroallergen exposure, we do not yet fully understand how RNA virus infections produce asthmatic exacerbations. This review will summarize the explosion of information that has revealed how patterns produced by RNA virus infection trigger the innate immune response (IIR) in sentinel airway cells. When the IIR is triggered, these cells elaborate inflammatory cytokines and protective mucosal interferons whose actions activate long-lived adaptive immunity and limit organismal replication. Recent work has shown the multifaceted way that dysregulation of the IIR is linked to viral-induced exacerbation, steroid insensitivity, and T helper polarization of adaptive immunity. New developments in quantitative proteomics now enable accurate identification of subgroups of individuals that demonstrate activation of IIR ("innate endotype"). Potential applications to clinical research are proposed. Together, these developments open realistic prospects for how identification of the IIR endotype may inform asthma therapy in the future.
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Affiliation(s)
- Allan R Brasier
- Institute for Translational Sciences, Department of Internal Medicine, Sealy Center for Molecular Medicine, 8.128 Medical Research Building, University of Texas Medical Branch, 301 University Blvd, Galveston, TX, 77555-1060, USA,
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87
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Izzedine H, Mangier M, Ory V, Zhang SY, Sendeyo K, Bouachi K, Audard V, Péchoux C, Soria JC, Massard C, Bahleda R, Bourry E, Khayat D, Baumelou A, Lang P, Ollero M, Pawlak A, Sahali D. Expression patterns of RelA and c-mip are associated with different glomerular diseases following anti-VEGF therapy. Kidney Int 2013; 85:457-70. [PMID: 24067439 DOI: 10.1038/ki.2013.344] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 05/25/2013] [Accepted: 07/12/2013] [Indexed: 12/14/2022]
Abstract
Renal toxicity constitutes a dose-limiting side effect of anticancer therapies targeting vascular endothelial growth factor (VEGF). In order to study this further, we followed up 29 patients receiving this treatment, who experienced proteinuria, hypertension, and/or renal insufficiency. Eight developed minimal change nephropathy/focal segmental glomerulopathy (MCN/FSG)-like lesions and 13 developed thrombotic microangiopathy (TMA). Patients receiving receptor tyrosine kinase inhibitors (RTKIs) mainly developed MCN/FSG-like lesions, whereas TMA complicated anti-VEGF therapy. There were no mutations in factor H, factor I, or membrane cofactor protein of the complement alternative pathway, while plasma ADAMTS13 activity persisted and anti-ADAMTS13 antibodies were undetectable in patients with TMA. Glomerular VEGF expression was undetectable in TMA and decreased in MCN/FSG. Glomeruli from patients with TMA displayed a high abundance of RelA in endothelial cells and in the podocyte nuclei, but c-mip was not detected. Conversely, MCN/FSG-like lesions exhibited a high abundance of c-mip, whereas RelA was scarcely detected. RelA binds in vivo to the c-mip promoter and prevents its transcriptional activation, whereas RelA knockdown releases c-mip activation. The RTKI sorafenib inhibited RelA activity, which then promoted c-mip expression. Thus, our results suggest that c-mip and RelA define two distinct types of renal damage associated with VEGF-targeted therapies.
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Affiliation(s)
- Hassan Izzedine
- Department of Nephrology, Pitie-Salpetriere Hospital, Paris, France
| | - Melanie Mangier
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France
| | - Virginie Ory
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France
| | - Shao-Yu Zhang
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France
| | - Kelhia Sendeyo
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France
| | - Khedidja Bouachi
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France [3] Service de Néphrologie, AP-HP, Groupe Hospitalier Henri Mondor-Albert Chenevier, Créteil, France
| | - Vincent Audard
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France [3] Service de Néphrologie, AP-HP, Groupe Hospitalier Henri Mondor-Albert Chenevier, Créteil, France
| | - Christine Péchoux
- INRA, UR1196 Génomique et Physiologie de la Lactation, Plateforme MIMA2, Jouy-en-Josas, France
| | | | | | | | - Edward Bourry
- Department of Nephrology, Pitie-Salpetriere Hospital, Paris, France
| | - David Khayat
- Department of Medical Oncology, Pitie-Salpetriere Hospital, Paris, France
| | - Alain Baumelou
- Department of Nephrology, Pitie-Salpetriere Hospital, Paris, France
| | - Philippe Lang
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France [3] Service de Néphrologie, AP-HP, Groupe Hospitalier Henri Mondor-Albert Chenevier, Créteil, France
| | - Mario Ollero
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France
| | - Andre Pawlak
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France
| | - Djillali Sahali
- 1] INSERM U 955, Equipe 21, Créteil, France [2] Université Paris-Est Creteil, Créteil, France [3] Service de Néphrologie, AP-HP, Groupe Hospitalier Henri Mondor-Albert Chenevier, Créteil, France
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88
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Freaney JE, Kim R, Mandhana R, Horvath CM. Extensive cooperation of immune master regulators IRF3 and NFκB in RNA Pol II recruitment and pause release in human innate antiviral transcription. Cell Rep 2013; 4:959-73. [PMID: 23994473 PMCID: PMC3792498 DOI: 10.1016/j.celrep.2013.07.043] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 07/16/2013] [Accepted: 07/29/2013] [Indexed: 11/29/2022] Open
Abstract
Transcription factors interferon regulatory factor 3 (IRF3) and nuclear factor κB (NFκB) are activated by external stimuli, including virus infection, to translocate to the nucleus and bind genomic targets important for immunity and inflammation. To investigate RNA polymerase II (Pol II) recruitment and elongation in the human antiviral gene regulatory network, a comprehensive genome-wide analysis was conducted during the initial phase of virus infection. Results reveal extensive integration of IRF3 and NFκB with Pol II and associated machinery and implicate partners for antiviral transcription. Analysis indicates that both de novo polymerase recruitment and stimulated release of paused polymerase work together to control virus-induced gene activation. In addition to known messenger-RNA-encoding loci, IRF3 and NFκB stimulate transcription at regions not previously associated with antiviral transcription, including abundant unannotated loci that encode novel virus-inducible RNAs (nviRNAs). These nviRNAs are widely induced by virus infections in diverse cell types and represent a previously overlooked cellular response to virus infection.
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Affiliation(s)
- Jonathan E. Freaney
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201, USA
| | - Rebecca Kim
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201, USA
| | - Roli Mandhana
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201, USA
| | - Curt M. Horvath
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201, USA
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89
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Yang J, Mitra A, Dojer N, Fu S, Rowicka M, Brasier AR. A probabilistic approach to learn chromatin architecture and accurate inference of the NF-κB/RelA regulatory network using ChIP-Seq. Nucleic Acids Res 2013; 41:7240-59. [PMID: 23771139 PMCID: PMC3753626 DOI: 10.1093/nar/gkt493] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Using nuclear factor-κB (NF-κB) ChIP-Seq data, we present a framework for iterative learning of regulatory networks. For every possible transcription factor-binding site (TFBS)-putatively regulated gene pair, the relative distance and orientation are calculated to learn which TFBSs are most likely to regulate a given gene. Weighted TFBS contributions to putative gene regulation are integrated to derive an NF-κB gene network. A de novo motif enrichment analysis uncovers secondary TFBSs (AP1, SP1) at characteristic distances from NF-κB/RelA TFBSs. Comparison with experimental ENCODE ChIP-Seq data indicates that experimental TFBSs highly correlate with predicted sites. We observe that RelA-SP1-enriched promoters have distinct expression profiles from that of RelA-AP1 and are enriched in introns, CpG islands and DNase accessible sites. Sixteen novel NF-κB/RelA-regulated genes and TFBSs were experimentally validated, including TANK, a negative feedback gene whose expression is NF-κB/RelA dependent and requires a functional interaction with the AP1 TFBSs. Our probabilistic method yields more accurate NF-κB/RelA-regulated networks than a traditional, distance-based approach, confirmed by both analysis of gene expression and increased informativity of Genome Ontology annotations. Our analysis provides new insights into how co-occurring TFBSs and local chromatin context orchestrate activation of NF-κB/RelA sub-pathways differing in biological function and temporal expression patterns.
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Affiliation(s)
- Jun Yang
- Department of Internal Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1060, USA, Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1060, USA, Institute for Translational Sciences, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1060, USA, Institute of Informatics, University of Warsaw, Banacha 2, 02-097, Warsaw, Poland and Sealy Center for Molecular Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1060, USA
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90
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Tian B, Zhao Y, Kalita M, Edeh CB, Paessler S, Casola A, Teng MN, Garofalo RP, Brasier AR. CDK9-dependent transcriptional elongation in the innate interferon-stimulated gene response to respiratory syncytial virus infection in airway epithelial cells. J Virol 2013; 87:7075-92. [PMID: 23596302 PMCID: PMC3676079 DOI: 10.1128/jvi.03399-12] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 04/08/2013] [Indexed: 12/20/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a negative-sense single-stranded RNA virus responsible for lower respiratory tract infections. During infection, the presence of double-stranded RNA (dsRNA) activates the interferon (IFN) regulatory factor 3 (IRF3) transcription factor, an event triggering expression of immediate early, IFN-stimulated genes (ISGs). We examine the role of transcriptional elongation in control of IRF3-dependent ISG expression. RSV infection induces ISG54, ISG56, and CIG5 gene expression in an IRF3-dependent manner demonstrated by IRF3 small interfering RNA (siRNA) silencing in both A549 epithelial cells and IRF3(-/-) MEFs. ISG expression was mediated by the recruitment of IRF3, CDK9, polymerase II (Pol II), and phospho-Ser(2) carboxy-terminal domain (CTD) Pol II to the IFN-stimulated response element (ISRE) binding sites of the IRF3-dependent ISG promoters in native chromatin. We find that RSV infection enhances the activated fraction of cyclin-dependent kinase 9 (CDK9) by promoting its association with bromodomain 4 (BRD4) and disrupting its association with the inhibitory 7SK small nuclear RNA. The requirement of CDK9 activity for ISG expression was shown by siRNA-mediated silencing of CDK9 and by a selective CDK9 inhibitor in A549 cells. In contrast, RSV-induced beta interferon (IFN-β) expression is not influenced by CDK9 inhibition. Using transcript-selective quantitative real-time reverse transcription-PCR (Q-RT-PCR) assays for the ISG54 gene, we observed that RSV induces transition from short to fully spliced mRNA transcripts and that this transition is blocked by CDK9 inhibition in both A549 and primary human small airway epithelial cells. These data indicate that transcription elongation plays a major role in RSV-induced ISG expression and is mediated by IRF3-dependent recruitment of activated CDK9. CDK9 activity may be a target for immunomodulation in RSV-induced lung disease.
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Affiliation(s)
| | - Yingxin Zhao
- Department of Internal Medicine,
- Institute for Translational Sciences,
- Sealy Center for Molecular Medicine,
| | | | | | | | - Antonella Casola
- Institute for Translational Sciences,
- Sealy Center for Molecular Medicine,
- Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Michael N. Teng
- Joy McCann Culverhouse Airway Disease Research Center, Department of Internal Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Roberto P. Garofalo
- Institute for Translational Sciences,
- Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Allan R. Brasier
- Department of Internal Medicine,
- Institute for Translational Sciences,
- Sealy Center for Molecular Medicine,
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91
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Kang Y, Wang F, Lu Z, Ying H, Zhang H, Ding W, Wang C, Shi L. MAPK kinase 3 potentiates Chlamydia HSP60-induced inflammatory response through distinct activation of NF-κB. THE JOURNAL OF IMMUNOLOGY 2013; 191:386-94. [PMID: 23729445 DOI: 10.4049/jimmunol.1300481] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Chlamydia pneumonia (C. pneumonia) remains one of the leading causes of bacterial pneumonia and has been implicated in the pathogenesis of some inflammation-related diseases, such as asthma, chronic obstructive pulmonary disease, and vascular diseases. Heat shock protein 60 is one of the pathogenic components of C. pneumonia that is closely associated with the inflammatory disorders. However, the molecular basis for the immunopathologic property of chlamydial heat shock protein (cHSP60) has not been elucidated. In this article, we report that MAPK kinase 3 (MKK3) is essential for cHSP60-induced lung inflammation, because MKK3-knockout mice displayed significantly reduced lung neutrophil accumulation and decreased production of proinflammatory mediators, correlating with the alleviated inflammatory response in lung tissues. Mechanistically, p38 kinase was selectively activated by MKK3 in response to cHSP60 and activated NF-κB by stimulating the nuclear kinase, mitogen- and stress-activated protein kinase 1. The specific knockdown of mitogen- and stress-activated protein kinase 1 in macrophages resulted in a defective phosphorylation of NF-κB/RelA at Ser(276) but had no apparent effect on RelA translocation. Furthermore, TGF-β-activated kinase 1 was found to relay the signal to MKK3 from TLR4, the major receptor that sensed cHSP60 in the initiation of the inflammatory response. Thus, we establish a critical role for MKK3 signaling in cHSP60 pathology and suggest a novel mechanism underlying C. pneumonia-associated inflammatory disorders.
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Affiliation(s)
- Yanhua Kang
- Department of Basic Medical Science, Key Laboratory of Immunology and Molecular Medicine, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China
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92
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Choudhary S, Kalita M, Fang L, Patel KV, Tian B, Zhao Y, Edeh CB, Brasier AR. Inducible tumor necrosis factor (TNF) receptor-associated factor-1 expression couples the canonical to the non-canonical NF-κB pathway in TNF stimulation. J Biol Chem 2013; 288:14612-14623. [PMID: 23543740 PMCID: PMC3656313 DOI: 10.1074/jbc.m113.464081] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 03/28/2013] [Indexed: 11/06/2022] Open
Abstract
The NF-κB transcription factor mediates the inflammatory response through distinct (canonical and non-canonical) signaling pathways. The mechanisms controlling utilization of either of these pathways are largely unknown. Here we observe that TNF stimulation induces delayed NF-κB2/p100 processing and investigate the coupling mechanism. TNF stimulation induces TNF-associated factor-1 (TRAF-1) that directly binds NF-κB-inducing kinase (NIK) and stabilizes it from degradation by disrupting its interaction with TRAF2·cIAP2 ubiquitin ligase complex. We show that TRAF1 depletion prevents TNF-induced NIK stabilization and reduces p52 production. To further examine the interactions of TRAF1 and NIK with NF-κB2/p100 processing, we mathematically modeled TRAF1·NIK as a coupling signaling complex and validated computational inference by siRNA knockdown to show non-canonical pathway activation is dependent not only on TRAF1 induction but also NIK stabilization by forming TRAF1·NIK complex. Thus, these integrated computational-experimental studies of TNF-induced TRAF1 expression identified TRAF1·NIK as a central complex linking canonical and non-canonical pathways by disrupting the TRAF2-cIAP2 ubiquitin ligase complex. This feed-forward kinase pathway is essential for the activation of non-canonical pathway.
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Affiliation(s)
- Sanjeev Choudhary
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas 77555.
| | - Mridul Kalita
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Ling Fang
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Kershaw V Patel
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas 77555
| | - Chukwudi B Edeh
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas 77555
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93
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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.
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Affiliation(s)
- Gil Diamant
- Dept. of Biological Chemistry, The Weizmann Institute of Science, Rehovot , Israel
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94
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Okuyama E, Suzuki A, Murata M, Ando Y, Kato I, Takagi Y, Takagi A, Murate T, Saito H, Kojima T. Molecular mechanisms of syndecan-4 upregulation by TNF-α in the endothelium-like EAhy926 cells. J Biochem 2013; 154:41-50. [PMID: 23576453 DOI: 10.1093/jb/mvt024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Syndecan-4, a cell-surface heparan sulfate proteoglycan, can participate in inflammation and wound healing as a host defense molecule. Tumour necrosis factor (TNF)-α, one of the most potent proinflammatory cytokines, is known to upregulate syndecan-4 expression, but the precise mechanisms are unclear. To elucidate these mechanisms in detail, we examined syndecan-4 upregulation by TNF-α in the endothelium-like EAhy926 cell. Of the two putative nuclear factor kappa-B (NF-κB) binding sites in the syndecan-4 gene (SDC4) promoter, deletion or mutation of one or both sites significantly diminished the effects of TNF-α. Electrophoretic mobility shift assays showed that p65 and c-Rel, but not p50, bound to these NF-κB binding sites, whereas pull-down assays showed binding of all three NF-κB components. Chromatin immunoprecipitation assays clearly showed that p65 and phosphorylated p65, but not p50 or c-Rel, bound to the SDC4 promoter. An NF-κB inhibitor, p65 knockdown and a transcriptional elongation inhibitor completely blocked the effect of TNF-α on SDC4 promoter activity and significantly, but not completely, blocked that on SDC4 mRNA expression. These data suggest that NF-κB p65 could be a key mediator of syndecan-4 upregulation by TNF-α through two binding sites in the SDC4 promoter, but other NF-κB-p65 independent pathways might also be involved through transcriptional elongation.
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Affiliation(s)
- Eriko Okuyama
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Japan
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95
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Macrophage glucose-6-phosphate dehydrogenase stimulates proinflammatory responses with oxidative stress. Mol Cell Biol 2013; 33:2425-35. [PMID: 23572562 DOI: 10.1128/mcb.01260-12] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) is a key enzyme that regulates cellular redox potential. In this study, we demonstrate that macrophage G6PD plays an important role in the modulation of proinflammatory responses and oxidative stress. The G6PD levels in macrophages in the adipose tissue of obese animals were elevated, and G6PD mRNA levels positively correlated with those of proinflammatory genes. Lipopolysaccharide (LPS) and free fatty acids, which initiate proinflammatory signals, stimulated macrophage G6PD. Overexpression of macrophage G6PD potentiated the expression of proinflammatory and pro-oxidative genes responsible for the aggravation of insulin sensitivity in adipocytes. In contrast, when macrophage G6PD was inhibited or suppressed via chemical inhibitors or small interfering RNA (siRNA), respectively, basal and LPS-induced proinflammatory gene expression was attenuated. Furthermore, macrophage G6PD increased activation of the p38 mitogen-activated protein kinase (MAPK) and NF-κB pathways, which may lead to a vicious cycle of oxidative stress and proinflammatory cascade. Together, these data suggest that an abnormal increase of G6PD in macrophages promotes oxidative stress and inflammatory responses in the adipose tissue of obese animals.
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96
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Cosimo E, McCaig AM, Carter-Brzezinski LJM, Wheadon H, Leach MT, Le Ster K, Berthou C, Durieu E, Oumata N, Galons H, Meijer L, Michie AM. Inhibition of NF-κB-mediated signaling by the cyclin-dependent kinase inhibitor CR8 overcomes prosurvival stimuli to induce apoptosis in chronic lymphocytic leukemia cells. Clin Cancer Res 2013; 19:2393-405. [PMID: 23532892 DOI: 10.1158/1078-0432.ccr-12-2170] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Chronic lymphocytic leukemia (CLL) is currently incurable with standard chemotherapeutic agents, highlighting the need for novel therapies. Overcoming proliferative and cytoprotective signals generated within the microenvironment of lymphoid organs is essential for limiting CLL progression and ultimately developing a cure. EXPERIMENTAL DESIGN We assessed the potency of cyclin-dependent kinase (CDK) inhibitor CR8, a roscovitine analog, to induce apoptosis in primary CLL from distinct prognostic subsets using flow cytometry-based assays. CLL cells were cultured in in vitro prosurvival and proproliferative conditions to mimic microenvironmental signals in the lymphoid organs, to elucidate the mechanism of action of CR8 in quiescent and proliferating CLL cells using flow cytometry, Western blotting, and quantitative real-time PCR. RESULTS CR8 was 100-fold more potent at inducing apoptosis in primary CLL cells than roscovitine, both in isolated culture and stromal-coculture conditions. Importantly, CR8 induced apoptosis in CD40-ligated CLL cells and preferentially targeted actively proliferating cells within these cultures. CR8 treatment induced downregulation of the antiapoptotic proteins Mcl-1 and XIAP, through inhibition of RNA polymerase II, and inhibition of NF-κB signaling at the transcriptional level and through inhibition of the inhibitor of IκB kinase (IKK) complex, resulting in stabilization of IκBα expression. CONCLUSIONS CR8 is a potent CDK inhibitor that subverts pivotal prosurvival and proproliferative signals present in the tumor microenvironment of CLL patient lymphoid organs. Our data support the clinical development of selective CDK inhibitors as novel therapies for CLL.
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Affiliation(s)
- Emilio Cosimo
- Institute of Cancer Sciences, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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97
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Abstract
The gene expression programs that establish and maintain specific cell states in humans are controlled by thousands of transcription factors, cofactors, and chromatin regulators. Misregulation of these gene expression programs can cause a broad range of diseases. Here, we review recent advances in our understanding of transcriptional regulation and discuss how these have provided new insights into transcriptional misregulation in disease.
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Affiliation(s)
- Tong Ihn Lee
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Richard A. Young
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts
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98
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Frank CG, Reguerio V, Rother M, Moranta D, Maeurer AP, Garmendia J, Meyer TF, Bengoechea JA. Klebsiella pneumoniae targets an EGF receptor-dependent pathway to subvert inflammation. Cell Microbiol 2013; 15:1212-33. [PMID: 23347154 DOI: 10.1111/cmi.12110] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 12/21/2012] [Accepted: 01/12/2013] [Indexed: 12/24/2022]
Abstract
The NF-κB transcriptional factor plays a key role governing the activation of immune responses. Klebsiella pneumoniae is an important cause of community-acquired and nosocomial pneumonia. Evidence indicates that K. pneumoniae infections are characterized by lacking an early inflammatory response. Recently, we have demonstrated that Klebsiella antagonizes the activation of NF-κB via the deubiquitinase CYLD. In this work, by applying a high-throughput siRNA gain-of-function screen interrogating the human kinome, we identified 17 kinases that when targeted by siRNA restored IL-1β-dependent NF-κB translocation in infected cells. Further characterization revealed that K. pneumoniae activates an EGF receptor (EGFR)-phosphatidylinositol 3-OH kinase (PI3K)-AKT-PAK4-ERK-GSK3β signalling pathway to attenuate the cytokine-dependent nuclear translocation of NF-κB. Our data also revealed that CYLD is a downstream effector of K. pneumoniae-induced EGFR-PI3K-AKT-PAK4-ERK-GSK3β signalling pathway. Our efforts to identify the bacterial factor(s)responsible for EGFR activation demonstrate that a capsule (CPS) mutant did not activate EGFR hence suggesting that CPS could mediate the activation of EGFR. Supporting this notion, purified CPS did activate EGFR as well as the EGFR-dependent PI3K-AKT-PAK4-ERK-GSK3β signalling pathway. CPS-mediated EGFR activation was dependent on a TLR4-MyD88-c-SRC-dependent pathway. Several promising drugs have been developed to antagonize this cascade. We propose that agents targeting this signalling pathway might provide selective alternatives for the management of K. pneumoniae pneumonias.
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Affiliation(s)
- Christian G Frank
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Recinto Hospital Joan March, 07110, Bunyola, Spain
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99
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Moles A, Sanchez AM, Banks PS, Murphy LB, Luli S, Borthwick L, Fisher A, O’Reilly S, van Laar JM, White SA, Perkins ND, Burt AD, Mann DA, Oakley F. Inhibition of RelA-Ser536 phosphorylation by a competing peptide reduces mouse liver fibrosis without blocking the innate immune response. Hepatology 2013; 57:817-28. [PMID: 22996371 PMCID: PMC3807604 DOI: 10.1002/hep.26068] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 05/24/2012] [Accepted: 08/29/2012] [Indexed: 12/15/2022]
Abstract
UNLABELLED Phosphorylation of the RelA subunit at serine 536 (RelA-P-Ser536) is important for hepatic myofibroblast survival and is mechanistically implicated in liver fibrosis. Here, we show that a cell-permeable competing peptide (P6) functions as a specific targeted inhibitor of RelA-P-Ser536 in vivo and exerts an antifibrogenic effect in two progressive liver disease models, but does not impair hepatic inflammation or innate immune responses after lipopolysaccharide challenge. Using kinase assays and western blotting, we confirm that P6 is a substrate for the inhibitory kappa B kinases (IKKs), IKKα and IKKβ, and, in human hepatic myofibroblasts, P6 prevents RelA-P-Ser536, but does not affect IKK activation of IκBα. We demonstrate that RelA-P-Ser536 is a feature of human lung and skin fibroblasts, but not lung epithelial cells, in vitro and is present in sclerotic skin and diseased lungs of patients suffering from idiopathic pulmonary fibrosis. CONCLUSION RelA-P-Ser536 may be a core fibrogenic regulator of fibroblast phenotype.
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Affiliation(s)
- Anna Moles
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Ana M Sanchez
- Institute for Cell and Molecular Biosciences, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Paul S Banks
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Lindsay B Murphy
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Saimir Luli
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Lee Borthwick
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Andrew Fisher
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Steven O’Reilly
- Musculoskeletal Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Jacob M van Laar
- Musculoskeletal Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Steven A White
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Neil D Perkins
- Institute for Cell and Molecular Biosciences, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Alastair D Burt
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Derek A Mann
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Fiona Oakley
- Fibrosis Research Group, Institute of Cellular Medicine, Newcastle UniversityNewcastle upon Tyne, United Kingdom,Address reprint requests to: Fiona Oakley, Ph.D., Fibrosis Research Group, Institute of cellular Medicine, Newcastle University, Room M4.158, 4th Floor Leech Building, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom. E-mail: ; fax: +44 191 222 5455
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Cyclin-dependent kinase 6 phosphorylates NF-κB P65 at serine 536 and contributes to the regulation of inflammatory gene expression. PLoS One 2012; 7:e51847. [PMID: 23300567 PMCID: PMC3530474 DOI: 10.1371/journal.pone.0051847] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 11/07/2012] [Indexed: 11/20/2022] Open
Abstract
Nuclear factor kappa-B (NF-κB) activates multiple genes with overlapping roles in cell proliferation, inflammation and cancer. Using an unbiased approach we identified human CDK6 as a novel kinase phosphorylating NF-κB p65 at serine 536. Purified and reconstituted CDK6/cyclin complexes phosphorylated p65 in vitro and in transfected cells. The physiological role of CDK6 for basal as well as cytokine-induced p65 phosphorylation or NF-κB activation was revealed upon RNAi-mediated suppression of CDK6. Inhibition of CDK6 catalytic activity by PD332991 suppressed activation of NF-κB and TNF-induced gene expression. In complex with a constitutively active viral cyclin CDK6 stimulated NF-κB p65-mediated transcription in a target gene specific manner and this effect was partially dependent on its ability to phosphorylate p65 at serine 536. Tumor formation in thymi and spleens of v-cyclin transgenic mice correlated with increased levels of p65 Ser536 phosphorylation, increased expression of CDK6 and upregulaton of the NF-κB target cyclin D3. These results suggest that aberrant CDK6 expression or activation that is frequently observed in human tumors can contribute through NF-κB to chronic inflammation and neoplasia.
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