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Deng Y, Wang J, Huang M, Xu G, Wei W, Qin H. Inhibition of miR-148a-3p resists hepatocellular carcinoma progress of hepatitis C virus infection through suppressing c-Jun and MAPK pathway. J Cell Mol Med 2018; 23:1415-1426. [PMID: 30565389 PMCID: PMC6349179 DOI: 10.1111/jcmm.14045] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 01/27/2023] Open
Abstract
Objectives The present study was committed to investigate the role of miR‐148a‐3p in HCC infected with hepatitis C virus (HCV) and the regulatory mechanism of miR‐148a‐3p/c‐Jun/MAPK signalling pathway. Methods Differential analysis and GSEA analysis were performed with R packages. QRT‐PCR and Western blot were used to detect RNA or protein level, respectively. The targeted relationship between miR‐148a‐3p and c‐Jun was predicted by TargetScan database and determined by double luciferase reporter assay. MTT assay and flow cytometry were used to evaluate cell proliferation, cell cycle and cell apoptosis, respectively. Results C‐Jun was up‐regulated, and MAPK signalling pathway was activated in HCV‐infected HCC cells. C‐Jun expression regulated inflammation‐related gene expression and had an influence on cell proliferation, cell cycle and cell apoptosis. MiR‐148a‐3p, down‐regulated in HCV‐infected HCC cells, could target c‐Jun mRNA to suppress c‐Jun protein expression. Conclusions MiR‐148a‐3p suppressed the proliferation of HCC cells infected with HCV through targeting c‐Jun mRNA.
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Affiliation(s)
- Yibin Deng
- Clinic Medicine Research Center of Hepatobiliary Diseases, The Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China.,Department of Infectious Diseases, The Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China.,Centre for Medical Laboratory Science, The Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China
| | - Jianchu Wang
- Clinic Medicine Research Center of Hepatobiliary Diseases, The Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China
| | - Meijin Huang
- Department of Infectious Diseases, The Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China
| | - Guidan Xu
- Centre for Medical Laboratory Science, The Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China
| | - Wujun Wei
- Centre for Medical Laboratory Science, The Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China
| | - Houji Qin
- Department of Infectious Diseases, The Affiliated Hospital of Youjiang Medical College for Nationalities, Baise, China
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2
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Rohatgi T, Sedehizade F, Reymann KG, Reiser G. Protease-Activated Receptors in Neuronal Development, Neurodegeneration, and Neuroprotection: Thrombin as Signaling Molecule in the Brain. Neuroscientist 2016; 10:501-12. [PMID: 15534036 DOI: 10.1177/1073858404269955] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Protease-activated receptors (PARs) belong to the superfamily of seven transmembrane domain G protein-coupled receptors. Four PAR subtypes are known, PAR-1 to -4. PARs are highly homologous between the species and are expressed in a wide variety of tissues and cell types. Of particular interest is the role which these receptors play in the brain, with regard to neuroprotection or degeneration under pathological conditions. The main agonist of PARs is thrombin, a multifunctional serine protease, known to be present not only in blood plasma but also in the brain. PARs possess an irreversible activation mechanism. Binding of agonist and subsequent cleavage of the extracellular N-terminus of the receptor results in exposure of a so-called tethered ligand domain, which then binds to extracellular loop 2 of the receptor leading to receptor activation. PARs exhibit an extensive expression pattern in both the central and the peripheral nervous system. PARs participate in several mechanisms important for normal cellular functioning and during critical situations involving cellular survival and death. In the last few years, research on Alzheimer’s disease and stroke has linked PARs to the pathophysiology of these neurodegenerative disorders. Actions of thrombin are concentration-dependent, and therefore, depending on cellular function and environment, serve as a double-edged sword. Thrombin can be neuroprotective during stress conditions, whereas under normal conditions high concentrations of thrombin are toxic to cells.
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Affiliation(s)
- Tanuja Rohatgi
- Institut für Neurobiochemie, Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Magdeburg, Germany
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3
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Yu OM, Brown JH. G Protein-Coupled Receptor and RhoA-Stimulated Transcriptional Responses: Links to Inflammation, Differentiation, and Cell Proliferation. Mol Pharmacol 2015; 88:171-80. [PMID: 25904553 DOI: 10.1124/mol.115.097857] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 04/22/2015] [Indexed: 01/06/2023] Open
Abstract
The low molecular weight G protein RhoA (rat sarcoma virus homolog family member A) serves as a node for transducing signals through G protein-coupled receptors (GPCRs). Activation of RhoA occurs through coupling of G proteins, most prominently, G12/13, to Rho guanine nucleotide exchange factors. The GPCR ligands that are most efficacious for RhoA activation include thrombin, lysophosphatidic acid, sphingosine-1-phosphate, and thromboxane A2. These ligands also stimulate proliferation, differentiation, and inflammation in a variety of cell and tissues types. The molecular events underlying these responses are the activation of transcription factors, transcriptional coactivators, and downstream gene programs. This review describes the pathways leading from GPCRs and RhoA to the regulation of activator protein-1, NFκB (nuclear factor κ-light-chain-enhancer of activated B cells), myocardin-related transcription factor A, and Yes-associated protein. We also focus on the importance of two prominent downstream transcriptional gene targets, the inflammatory mediator cyclooxygenase 2, and the matricellular protein cysteine-rich angiogenic inducer 61 (CCN1). Finally, we describe the importance of GPCR-induced activation of these pathways in the pathophysiology of cancer, fibrosis, and cardiovascular disease.
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Affiliation(s)
- Olivia M Yu
- Department of Pharmacology (O.Y., J.H.B.) and Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, California (O.Y.)
| | - Joan Heller Brown
- Department of Pharmacology (O.Y., J.H.B.) and Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, California (O.Y.)
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4
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Qin Q, Chen M, Yi B, You X, Yang P, Sun J. Orphan nuclear receptor Nur77 is a novel negative regulator of endothelin-1 expression in vascular endothelial cells. J Mol Cell Cardiol 2014; 77:20-8. [PMID: 25284689 DOI: 10.1016/j.yjmcc.2014.09.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/15/2014] [Accepted: 09/25/2014] [Indexed: 12/11/2022]
Abstract
Endothelin-1 (ET-1) produced by vascular endothelial cells plays essential roles in the regulation of vascular tone and development of cardiovascular diseases. The objective of this study is to identify novel regulators implicated in the regulation of ET-1 expression in vascular endothelial cells (ECs). By using quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA), we show that either ectopic expression of orphan nuclear receptor Nur77 or pharmacological activation of Nur77 by 6-mercaptopurine (6-MP) substantially inhibits ET-1 expression in human umbilical vein endothelial cells (HUVECs), under both basal and thrombin-stimulated conditions. Furthermore, thrombin-stimulated ET expression is significantly augmented in both Nur77 knockdown ECs and aort from Nur77 knockout mice, suggesting that Nur77 is a negative regulator of ET-1 expression. Inhibition of ET-1 expression by Nur77 occurs at gene transcriptional levels, since Nur77 potently inhibits ET-1 promoter activity, without affecting ET-1 mRNA stability. As shown in electrophoretic mobility shift assay (EMSA), Nur77 overexpression markedly inhibits both basal and thrombin-stimulated transcriptional activity of AP-1. Mechanistically, we demonstrate that Nur77 specially interacts with c-Jun and inhibits AP-1 dependent c-Jun promoter activity, which leads to a decreased expression of c-Jun, a critical component involved in both AP-1 transcriptional activity and ET-1 expression in ECs. These findings demonstrate that Nur77 is a novel negative regulator of ET-1 expression in vascular ECs through an inhibitory interaction with the c-Jun/AP-1 pathway. Activation of Nur77 may represent a useful therapeutic strategy for preventing certain cardiovascular diseases, such as atherosclerosis and pulmonary artery hypertension.
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Affiliation(s)
- Qing Qin
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA; Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Ming Chen
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Bing Yi
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Xiaohua You
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Ping Yang
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Jianxin Sun
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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5
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Keim A, Müller I, Thiel G. Efficient genetic manipulation of 1321N1 astrocytoma cells using lentiviral gene transfer. J Neurosci Methods 2012; 206:138-42. [DOI: 10.1016/j.jneumeth.2012.02.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 02/14/2012] [Accepted: 02/15/2012] [Indexed: 10/28/2022]
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Fabbro S, Seeds NW. Plasminogen activator activity is inhibited while neuroserpin is up-regulated in the Alzheimer disease brain. J Neurochem 2009; 109:303-15. [PMID: 19222708 DOI: 10.1111/j.1471-4159.2009.05894.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Amyloid-beta plaques are a pathological hallmark of Alzheimer's disease. Several proteases are known to cleave/remove amyloid-beta, including plasmin, the product of tissue plasminogen activator cleavage of the pro-enzyme plasminogen. Although plasmin levels are lower in Alzheimer brain, there has been little analysis of the plasminogen activator/plasmin system in the brains of Alzheimer patients. In this study, zymography, immunocapture, and ELISAs were utilized to show that tissue plasminogen activator activity in frontal cortex tissue of Alzheimer patients is dramatically reduced compared with age-matched controls, while tissue plasminogen activator and plasminogen protein levels are unchanged; suggesting that plasminogen activator activity is inhibited in the Alzheimer brain. Analysis of endogenous plasminogen activator inhibitors shows that while plasminogen activator inhibitor-1 and protease nexin-1 levels are unchanged, the neuroserpin levels are significantly elevated in brains of Alzheimer patients. Furthermore, elevated amounts of tissue plasminogen activator-neuroserpin complexes are seen in the Alzheimer brain, and immunohistochemical studies demonstrate that both tissue plasminogen activator and neuroserpin are associated with amyloid-beta plaques in Alzheimer brain tissue. Thus, neuroserpin inhibition of tissue plasminogen activator activity leads to reduced plasmin and may be responsible for reduced clearance of amyloid-beta in the Alzheimer disease brain. Furthermore, decreased tissue plasminogen activator activity in the Alzheimer brain may directly influence synaptic activity and impair cognitive function.
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Affiliation(s)
- Shay Fabbro
- Neuroscience Program and Department of Biochemistry and Molecular Genetics, University of Colorado Denver, Aurora, USA
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7
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Walsh CT, Radeff-Huang J, Matteo R, Hsiao A, Subramaniam S, Stupack D, Brown JH. Thrombin receptor and RhoA mediate cell proliferation through integrins and cysteine-rich protein 61. FASEB J 2008; 22:4011-21. [PMID: 18687805 DOI: 10.1096/fj.08-113266] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A subset of G-protein coupled receptors (GPCRs), including the thrombin receptor (PAR1), elicits mitogenic responses. Thrombin also activates Ras homolog gene family member A (RhoA) and activating protein (AP-1) -mediated gene expression in 1321N1 astrocytoma cells, whereas the nonmitogenic agonist carbachol does not. Transcriptomic analysis was used to explore differential gene induction by these agonists and revealed that the matricellular protein cysteine-rich 61 (Cyr61/CCN1) is selectively induced by thrombin. The ability of GPCR agonists to induce Cyr61 parallels their ability to activate RhoA; agonist-stimulated Cyr61 expression is inhibited by C3 toxin. When Cyr61 is down-regulated using short interfering RNA (siRNA) or short-hairpin RNA (shRNA), thrombin-induced DNA synthesis is significantly attenuated. When Cyr61 expression is induced, it appears in the extracellular compartment and on the cell surface. Extracellular Cyr61 interacts with alpha(5), alpha(6), and beta(1) integrins on these cells, and monoclonal antibodies directed against alpha(5) and beta(1) integrins inhibit thrombin-induced DNA synthesis. Functional blockade of Cyr61 with soluble heparin or anti-Cyr61 antibodies also inhibits thrombin-induced DNA synthesis. Thus Cyr61 is a highly inducible, secreted extracellular factor through which GPCR and RhoA signaling pathways engage integrins that contribute to GPCR-mediated proliferation.
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Affiliation(s)
- Colin T Walsh
- Joan Heller Brown, Department of Pharmacology, University of California San Diego, 9500 Gilman Dr.-0636, La Jolla, CA 92093, USA
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8
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Silvers AL, Bowden GT. UVA Irradiation-induced Activation of Activator Protein-1 is Correlated with Induced Expression of AP-1 Family Members in the Human Keratinocyte Cell Line HaCaT¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0750302uiiaoa2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Geller SF, Stone J. Quantitative PCR analysis of FosB mRNA expression after short duration oxygen and light stress. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 533:249-57. [PMID: 15180271 DOI: 10.1007/978-1-4615-0067-4_31] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Quantitative polymerase chain reaction (QPCR) was used to examine changes in FosB mRNA expression in models of oxygen and light stress to the retina. C57BL/6 mice or Sprague-Dawley (SD) albino rats were subjected to several experimental paradigms: short-term light or oxygen stress, extended hyperoxia (75% oxygen), or a model of oxygen-induced retinopathy (OIR). Control animals were subjected to room air and 5 lux cyclic light. FosB expression dramatically increases in response to light stress as well as in a model of OIR, but not in response to sustained 75% oxygen. These data suggest that both hypoxia and light stress induce expression of FosB in the retina.
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Affiliation(s)
- Scott F Geller
- School of Optometry, University of California, Berkeley, CA 94720-2020, USA.
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10
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Gangnuss S, Cowin AJ, Daehn IS, Hatzirodos N, Rothnagel JA, Varelias A, Rayner TE. Regulation of MAPK Activation, AP-1 Transcription Factor Expression and Keratinocyte Differentiation in Wounded Fetal Skin. J Invest Dermatol 2004; 122:791-804. [PMID: 15086567 DOI: 10.1111/j.0022-202x.2004.22319.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Fetal epithelium retains the ability to re-epithelialize a wound in organotypic culture in a manner not dependent on the presence of underlying dermal substrata. This capacity is lost late in the third trimester of gestation or after embryonic day 17 (E(17)) in the rat such that embryonic day 19 (E(19)) wounds do not re-epithelialize. Moreover, wounds created in E(17) fetuses in utero heal in a regenerative, scar-free fashion. To investigate the molecular events regulating re-epithelialization in fetal skin, the wound-induced expression profile and tissue localization of activator protein 1 (AP-1) transcription factors c-Fos and c-Jun was characterised in E(17) and E(19) skin using organotypic fetal cultures. The involvement of mitogen-activated protein kinase (MAPK) signaling in mediating wound-induced transcription factor expression and wound re-epithelialization was assessed, with the effect of wounding on the expression of keratinocyte differentiation markers determined. Our results show that expression of AP-1 transcription factors was induced immediately by wounding and localized predominantly to the epidermis in E(17) and E(19) skin. c-fos and c-jun induction was transient in E(17) skin with MAPK-dependent c-fos expression necessary for the re-epithelialization of an excisional wound in organotypic culture. In E(19) skin, AP-1 expression persisted beyond 12 h post-wounding, and marked upregulation of the keratinocyte differentiation markers keratin 10 and loricrin was observed. No such changes in the expression of keratin 10 or loricrin occurred in E(17) skin. These findings indicate that re-epithelialization in fetal skin is regulated by wound-induced AP-1 transcription factor expression via MAPK and the differentiation status of keratinocytes.
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Affiliation(s)
- Samantha Gangnuss
- Wound Healing and Injury Research Centre, The University of Adelaide Department of Surgery, The Queen Elizabeth Hospital, Woodville, South Australia
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11
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Marinissen MJ, Servitja JM, Offermanns S, Simon MI, Gutkind JS. Thrombin protease-activated receptor-1 signals through Gq- and G13-initiated MAPK cascades regulating c-Jun expression to induce cell transformation. J Biol Chem 2003; 278:46814-25. [PMID: 12954641 DOI: 10.1074/jbc.m305709200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although the ability of G protein-coupled receptors to stimulate normal and aberrant cell growth has been intensely investigated, the precise nature of the molecular mechanisms underlying their transforming potential are still not fully understood. In this study, we have taken advantage of the potent mitogenic effect of thrombin and the focus-forming activity of one of its receptors, protease-activated receptor-1, to dissect how this receptor coupled to Galphai, Galphaq/11, and Galpha12/13 transduces signals from the membrane to the nucleus to initiate transcriptional events involved in cell transformation. Using endogenous and transfected thrombin receptors in NIH 3T3 cells, ectopic expression of muscarinic receptors coupled to Galphaq and Galphai, and chimeric G protein alpha subunits and murine fibroblasts deficient in Galphaq/11, and Galpha12/13, we show here that, although coupling to Galphai is sufficient to induce ERK activation, the ability to couple to Galphaq and/or Galpha13 is necessary to induce c-jun expression and cell transformation. Furthermore, we show that Galphaq and Galpha13 can initiate the activation of MAPK cascades, including JNK, p38, and ERK5, which in turn regulate the activity of transcription factors controlling expression from the c-jun promoter. We also present evidence that c-Jun and the kinases regulating its expression are integral components of the transforming pathway initiated by protease-activated receptor-1.
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Affiliation(s)
- Maria Julia Marinissen
- Oral and Pharyngeal Cancer Branch, NIDCR/National Institutes of Health, Building 30, Room 211, 9000 Rockville Pike, Bethesda, MD 20892-4330, USA
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12
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Woodcock EA, Wang BH, Arthur JF, Lennard A, Matkovich SJ, Du XJ, Brown JH, Hannan RD. Inositol polyphosphate 1-phosphatase is a novel antihypertrophic factor. J Biol Chem 2002; 277:22734-42. [PMID: 11932254 DOI: 10.1074/jbc.m110405200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Activation of G(q)-coupled alpha(1)-adrenergic receptors leads to hypertrophic growth of neonatal rat ventricular cardiomyocytes that is associated with increased expression of hypertrophy-related genes, including atrial natriuretic peptide (ANP) and myosin light chain-2 (MLC), as well as increased ribosome synthesis. The role of inositol phosphates in signaling pathways involved in these changes in gene expression was examined by overexpressing inositol phosphate-metabolizing enzymes and determining effects on ANP, MLC, and 45 S ribosomal gene expression following co-transfection of appropriate reporter gene constructs. Overexpression of enzymes that metabolize inositol 1,4,5-trisphosphate did not reduce ANP or MLC responses, but overexpression of the enzyme primarily responsible for metabolism of inositol 4,5-bisphosphate (Ins(1,4)P(2)), inositol polyphosphate 1-phosphatase (INPP), reduced ANP and MLC responses associated with alpha(1)-adrenergic receptor-mediated hypertrophy. Similarly overexpressed INPP reduced ANP and MLC responses associated with contraction-induced hypertrophy. In addition, overexpression of INPP reduced the increase in ribosomal DNA transcription associated with both hypertrophic models. Hypertrophied cells from both cell models as well as ventricular tissue from mouse hearts hypertrophied by pressure overload in vivo contained heightened levels of Ins(1,4)P(2), suggesting reduced INPP activity in three different models of hypertrophy. These studies provide evidence for an involvement of Ins(1,4)P(2) in hypertrophic signaling pathways in ventricular myocytes.
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MESH Headings
- Animals
- Atrial Natriuretic Factor/metabolism
- Blotting, Western
- CHO Cells
- Cardiac Myosins/metabolism
- Cells, Cultured
- Cloning, Molecular
- Cricetinae
- DNA, Complementary/metabolism
- DNA, Ribosomal/metabolism
- Electrophoresis, Polyacrylamide Gel
- Gene Library
- Genes, Reporter
- Humans
- Hypertrophy/drug therapy
- Inositol Phosphates/metabolism
- Mice
- Mice, Inbred C57BL
- Models, Chemical
- Myocardium/metabolism
- Myocardium/pathology
- Myosin Light Chains/metabolism
- Phosphoric Monoester Hydrolases/chemistry
- Phosphoric Monoester Hydrolases/pharmacology
- Promoter Regions, Genetic
- Protein Binding
- Protein Kinase C/metabolism
- Rats
- Signal Transduction
- Time Factors
- Transcription, Genetic
- Transfection
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Affiliation(s)
- Elizabeth A Woodcock
- Cellular Biochemistry Laboratory, Baker Medical Research Institute, PO Box 6492, St. Kilda Road Central, Melbourne, 8008, Victoria, Australia.
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13
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Silvers AL, Bowden GT. UVA irradiation-induced activation of activator protein-1 is correlated with induced expression of AP-1 family members in the human keratinocyte cell line HaCaT. Photochem Photobiol 2002; 75:302-10. [PMID: 11950097 DOI: 10.1562/0031-8655(2002)075<0302:uiiaoa>2.0.co;2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To determine whether the transcription factor activator protein-1 (AP-1) could be modulated by ultraviolet A (UVA) exposure, we examined AP-1 DNA-binding activity and transactivation after exposure to UVA in the human immortalized keratinocyte cell line HaCaT. Maximal AP-1 transactivation was observed with 250 kJ/m2 UVA between 3 and 4 h after irradiation. DNA binding of AP-1 to the target 12-O-tetradecanoylphorbol-13-acetate response element sequence was maximally induced 1-3 h after irradiation. Both de novo transcription and translation contributed to the UVA-induced AP-1 DNA binding. c-Fos was implicated as a primary component of the AP-1 DNA-binding complex. Other components of the complex included Fra-2, c-Jun, JunB and JunD. UVA irradiation induced protein expression of c-Fos, c-Jun, Fra-1 and Fra-2. Phosphorylated forms of these induced proteins were determined at specific time points. A strong correlation existed between UVA-induced AP-1 activity and accumulation of c-Fos, c-Jun and Fra-1 proteins. UVA irradiation also induced c-fos and c-jun mRNA expression and transcriptional activation of the c-fos gene promoter. These results demonstrate that UVA irradiation activates AP-1 and that c-fos induction may play a critical role in the response of these human keratinocytes to UVA irradiation.
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Affiliation(s)
- Amy L Silvers
- Department of Radiation Oncology, Arizona Cancer Center, The University of Arizona, Tucson 85724, USA
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14
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Kataoka K, Handa H, Nishizawa M. Induction of cellular antioxidative stress genes through heterodimeric transcription factor Nrf2/small Maf by antirheumatic gold(I) compounds. J Biol Chem 2001; 276:34074-81. [PMID: 11429414 DOI: 10.1074/jbc.m105383200] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gold(I)-containing compounds have long been used in the treatment of rheumatoid arthritis (RA), but the molecular mechanism of their action has remained largely unknown. In this paper we have demonstrated that gold(I) drugs selectively activate the DNA binding of a heterodimer consisting of the basic-leucine zipper transcription factors Nrf2 and small Maf. Once bound to its recognition DNA sequence termed antioxidant-responsive element or Maf-recognition element, Nrf2/small Maf induces a set of antioxidative stress genes, including heme oxygenase-1 and gamma-glutamylcysteine synthetase, whose products have been demonstrated to contribute to the scavenging of reactive oxygen species and to exhibit anti-inflammatory effects. Our findings suggest that stimulation of antioxidative stress response through activation of Nrf2/small Maf may be a pharmacologically important part of the actions of gold(I) drugs for the treatment of rheumatoid arthritis. Alternatively, activation of Nrf2/small Maf may be a protective response of cells against toxic effects of the drugs.
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Affiliation(s)
- K Kataoka
- Frontier Collaborative Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, 226-8503 Yokohama, Japan.
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15
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van der Fits L, Memelink J. The jasmonate-inducible AP2/ERF-domain transcription factor ORCA3 activates gene expression via interaction with a jasmonate-responsive promoter element. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2001; 25:43-53. [PMID: 11169181 DOI: 10.1111/j.1365-313x.2001.00932.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The AP2/ERF-domain transcription factor ORCA3 is a master regulator of primary and secondary metabolism in Catharanthus roseus (periwinkle). Here we demonstrate that ORCA3 specifically binds to and activates gene expression via a previously characterized jasmonate- and elicitor-responsive element (JERE) in the promoter of the terpenoid indole alkaloid biosynthetic gene Strictosidine synthase (Str). Functional characterization of different domains in the ORCA3 protein in yeast and plant cells revealed the presence of an N-terminal acidic activation domain and a serine-rich C-terminal domain with a negative regulatory function. Orca3 mRNA accumulation was rapidly induced by the plant stress hormone methyljasmonate with biphasic kinetics. A precursor and an intermediate of the jasmonate biosynthetic pathway also induced Orca3 gene expression, further substantiating the role for ORCA3 in jasmonate signaling. The protein synthesis inhibitor cycloheximide did not inhibit jasmonate-responsive expression of Orca3, nor of its target genes Str and Tryptophan decarboxylase (Tdc). In conclusion, ORCA3 regulates jasmonate-responsive expression of the Str gene via direct interaction with the JERE. The activating activities of ORCA proteins do not seem to depend on jasmonate-induced de novo protein synthesis, but presumably occur via modification of pre-existing ORCA protein.
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Affiliation(s)
- L van der Fits
- Institute of Molecular Plant Sciences, Clusius Laboratory, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
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16
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Bortnick AE, Rothblat GH, Stoudt G, Hoppe KL, Royer LJ, McNeish J, Francone OL. The correlation of ATP-binding cassette 1 mRNA levels with cholesterol efflux from various cell lines. J Biol Chem 2000; 275:28634-40. [PMID: 10893411 DOI: 10.1074/jbc.m003407200] [Citation(s) in RCA: 250] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Studies show that lipid-free apoA-I stimulates release of cholesterol and phospholipid from fibroblasts and macrophages. ATP-binding cassette 1 (ABC1) is implicated in this release and has been identified as the genetic defect in Tangier disease, evidence that ABC1 is critical to the biogenesis of high density lipoprotein. We quantified levels of ABC1 mRNA, protein, and cholesterol efflux from J774 mouse macrophages +/- exposure to a cAMP analog. Up-regulating ABC1 mRNA correlated to increased cholesterol efflux in a dose- and time-dependent manner. mRNA levels rose after 15 min of exposure while protein levels rose after 1 h, with increased efflux 2-4 h post-treatment. In contrast to cells from wild-type mice, peritoneal macrophages from the Abc1 -/- mouse showed a lower level of basal efflux and no increase with cAMP treatment. The stimulation of efflux exhibits specificity for apoA-I, high density lipoprotein, and other apolipoproteins as cholesterol acceptors, but not for small unilamellar vesicles, bile acid micelles, or cyclodextrin. We have studied a number of cell types and found that while other cell lines express ABC1 constitutively, only J774 and elicited mouse macrophages show a substantial increase of mRNA and efflux with cAMP treatment. ApoA-I-stimulated efflux was detected from the majority of cell lines examined, independent of treatment.
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Affiliation(s)
- A E Bortnick
- MCP Hahnemann University, Department of Biochemistry, Philadelphia, Pennsylvania 19129, USA
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17
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Affiliation(s)
- V L Turgeon
- Furman University, Department of Biology, Greenville, SC 29613, USA.
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18
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Delerive P, Martin-Nizard F, Chinetti G, Trottein F, Fruchart JC, Najib J, Duriez P, Staels B. Peroxisome proliferator-activated receptor activators inhibit thrombin-induced endothelin-1 production in human vascular endothelial cells by inhibiting the activator protein-1 signaling pathway. Circ Res 1999; 85:394-402. [PMID: 10473669 DOI: 10.1161/01.res.85.5.394] [Citation(s) in RCA: 341] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Endothelin-1 (ET-1), a 21-amino acid vasoactive peptide mainly produced by vascular endothelial cells, is involved in the regulation of vascular tone and smooth muscle cell proliferation. Peroxisome proliferator-activated receptors (PPARs), key players in lipid and glucose metabolism, have been implicated in metabolic disorders that are predisposing to atherosclerosis. Because of the potential role of ET-1 in vascular disorders such as hypertension and atherosclerosis, we investigated the regulation of ET-1 expression by PPAR activators. Western blot and reverse transcription-polymerase chain reaction analyses demonstrated that both PPARalpha and PPARgamma are expressed in human coronary artery endothelial cells as well as in endothelial cell lines such as HMEC-1 and ECV304. In bovine aortic endothelial cells and HMEC-1 cells, both PPARalpha and PPARgamma ligands inhibited thrombin-induced ET-1 secretion, whereas basal ET-1 secretion was only slightly suppressed. Reverse transcription-polymerase chain reaction experiments showed that this inhibition of ET-1 production occurs at the gene expression level. Using transient transfection assays, we demonstrated that PPARs downregulate thrombin-activated transcription of the human ET-1 promoter. Transactivation studies with c-Jun and c-Fos expression plasmids indicated that PPARs negatively interfere with the activator protein-1 signaling pathway, which mediates thrombin activation of ET-1 gene transcription. Furthermore, electrophoretic mobility shift assays demonstrated that PPAR activators reduce the thrombin-stimulated binding activity of bovine aortic endothelial cell nuclear extracts as well as c-Jun binding to an activator protein-1 consensus site. Taken together, these data indicate that (1) both PPARalpha and PPARgamma are expressed in human vascular endothelial cells and (2) PPAR activators inhibit thrombin-induced ET-1 biosynthesis, indicating a novel role for PPARs in vascular endothelial function.
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Affiliation(s)
- P Delerive
- U.325 INSERM, Département d'Athérosclérose, Institut Pasteur de Lille, Lille, France
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19
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Shaw PA, Chaparro O. The 5'-flanking sequence and regulatory elements of the cystatin S gene. Biochem Biophys Res Commun 1999; 261:705-11. [PMID: 10441490 DOI: 10.1006/bbrc.1999.1072] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The gene encoding rat cystatin S (Cys S), a salivary gland-specific secretory protein, has CAAT and TATA boxes upstream of the inititation codon (Cox and Shaw, 1992), and contains regions that resemble those of other hormonally responsive eukaryotic genes. The 5'-flanking sequence of the rat Cys S gene has a potential CREB/AP-1 binding site (Rupp et al., 1990; Trejo et al., 1992), two potential glucocorticoid responsive elements (GREs, Drouin et al., 1989), and a possible GR/PR (glucocorticoid/progesterone) responsive element (Forman and Samuels, 1990). One of these potential GREs is adjacent to a potential AP-2 binding site, and another is typical of the glucocorticoid and progesterone receptor binding site. In this report, we have identified three regions in the 5'-flanking region of the Cys S gene that are found in salivary gland-specific genes (Ting et al., 1992) with a GT-rich region located between conserved elements II and III. Transfection experiments described in this paper suggest that a 281-bp DNA fragment from the Cys S gene promoter region with conserved elements II and III, the GT-rich region, and a possible GR/PR responsive element contains a negative regulatory element. In addition, our experiments suggest that the GT-rich region by itself is acting as a positive regulatory element.
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Affiliation(s)
- P A Shaw
- Department of Cell Biology and Anatomy, Mount Sinai School of Medicine, New York, New York, 10029, USA.
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20
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Rahman A, Anwar KN, True AL, Malik AB. Thrombin-Induced p65 Homodimer Binding to Downstream NF-κB Site of the Promoter Mediates Endothelial ICAM-1 Expression and Neutrophil Adhesion. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.9.5466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
We investigated the mechanisms by which proinflammatory mediator, thrombin, released during intravascular coagulation and tissue injury, induces ICAM-1 (CD54) expression in endothelial cells. Stimulation of HUVEC with thrombin resulted in dose- and time-dependent increases in ICAM-1 mRNA and cell surface expression and in ICAM-1-dependent endothelial adhesivity toward polymorphonuclear leukocytes. Transient transfection of endothelial cells with ICAM-1 promoter luciferase reporter gene (ICAM-1LUC) constructs indicated that deletion of upstream NF-κB site (−533 bases from translation start site) had no effect on thrombin responsiveness, whereas mutation/deletion of downstream NF-κB site (−223 bases from the translation start site) prevented the activation of ICAM-1 promoter, indicating that the downstream NF-κB site is critical for thrombin inducibility. NF-κB-directed luciferase activity increased ∼3-fold when cells transfected with the plasmid pNF-κBLUC containing five copies of consensus NF-κB site linked to a minimal adenovirus E1B promoter-luciferase gene were exposed to thrombin, indicating that activation of NF-κB was essential for thrombin response. Gel supershift assays demonstrated that thrombin induced binding of NF-κBp65 (Rel A) to downstream NF-κB site of the ICAM-1 promoter. Thrombin receptor activation peptide, a 14-amino-acid peptide representing the new NH2 terminus of proteolytically activated receptor-1, mimicked thrombin’s action in inducing ICAM-1 expression. These data indicate that thrombin activates endothelial ICAM-1 expression and polymorphonuclear leukocyte adhesion by NF-κBp65 binding to the downstream NF-κB site of ICAM-1 promoter after proteolytically activated receptor-1 activation.
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Affiliation(s)
- Arshad Rahman
- Department of Pharmacology, College of Medicine, University of Illinois, Chicago, IL 60612
| | - Khandaker N. Anwar
- Department of Pharmacology, College of Medicine, University of Illinois, Chicago, IL 60612
| | - Andrea L. True
- Department of Pharmacology, College of Medicine, University of Illinois, Chicago, IL 60612
| | - Asrar B. Malik
- Department of Pharmacology, College of Medicine, University of Illinois, Chicago, IL 60612
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21
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Herdegen T, Leah JD. Inducible and constitutive transcription factors in the mammalian nervous system: control of gene expression by Jun, Fos and Krox, and CREB/ATF proteins. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1998; 28:370-490. [PMID: 9858769 DOI: 10.1016/s0165-0173(98)00018-6] [Citation(s) in RCA: 1056] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article reviews findings up to the end of 1997 about the inducible transcription factors (ITFs) c-Jun, JunB, JunD, c-Fos, FosB, Fra-1, Fra-2, Krox-20 (Egr-2) and Krox-24 (NGFI-A, Egr-1, Zif268); and the constitutive transcription factors (CTFs) CREB, CREM, ATF-2 and SRF as they pertain to gene expression in the mammalian nervous system. In the first part we consider basic facts about the expression and activity of these transcription factors: the organization of the encoding genes and their promoters, the second messenger cascades converging on their regulatory promoter sites, the control of their transcription, the binding to dimeric partners and to specific DNA sequences, their trans-activation potential, and their posttranslational modifications. In the second part we describe the expression and possible roles of these transcription factors in neural tissue: in the quiescent brain, during pre- and postnatal development, following sensory stimulation, nerve transection (axotomy), neurodegeneration and apoptosis, hypoxia-ischemia, generalized and limbic seizures, long-term potentiation and learning, drug dependence and withdrawal, and following stimulation by neurotransmitters, hormones and neurotrophins. We also describe their expression and possible roles in glial cells. Finally, we discuss the relevance of their expression for nervous system functioning under normal and patho-physiological conditions.
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Affiliation(s)
- T Herdegen
- Institute of Pharmacology, University of Kiel, Hospitalstrasse 4, 24105, Kiel,
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22
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Protease-Activated Receptor 1 (PAR-1) Is Required and Rate-Limiting for Thrombin-Enhanced Experimental Pulmonary Metastasis. Blood 1998. [DOI: 10.1182/blood.v92.10.3694] [Citation(s) in RCA: 145] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThrombin-treated tumor cells induce a metastatic phenotype in experimental pulmonary murine metastasis. Thrombin binds to a unique protease-activated receptor (PAR-1) that requires N-terminal proteolytic cleavage for activation by its tethered end. A 14-mer thrombin receptor activation peptide (TRAP) of the tethered end induces the same cellular changes as thrombin. Four murine tumor cells (Lewis lung, CT26 colon CA, B16F10 melanoma, and CCL163 fibroblasts) contain PAR-1, as detected by reverse transcriptase-polymerase chain reaction (RT-PCR). B16F10 cells did not contain the two other thrombin receptors, PAR-3 and glycoprotein Ib. TRAP-treated B16F10 tumor cells enhance pulmonary metastasis 41- to 48-fold (n = 17). Thrombin-treated B16F10 cells transfected with full-length murine PAR-1 sense cDNA (S6, S7, S14, and S22) enhanced their adhesion to fibronectin 1.5- to 2.4-fold (n = 5, P < .04), whereas thrombin-treated wild-type cells do not. S6 (adhesion index, 1.5-fold) and S14 (index, 2.4-fold) when examined by RT-PCR and Northern analysis showed minimal expression of PAR-1 for S6 over wild-type and considerable expression for S14. Immunohistochemistry showed greater expression of PAR-1 for S14 compared with wild-type or empty-plasmid transfected cells. In vivo experiments with the thrombin-treated S14 transfectant showed a fivefold to sixfold increase in metastases compared with empty-plasmid transfected thrombin-treated naive cells or S6 cells (n = 20, P = .0001 to .02). Antisense had no effect on thrombin-stimulated tumor mass. Thus, PAR-1 ligation and expression enhances and regulates tumor metastasis.
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Protease-Activated Receptor 1 (PAR-1) Is Required and Rate-Limiting for Thrombin-Enhanced Experimental Pulmonary Metastasis. Blood 1998. [DOI: 10.1182/blood.v92.10.3694.422k40_3694_3700] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thrombin-treated tumor cells induce a metastatic phenotype in experimental pulmonary murine metastasis. Thrombin binds to a unique protease-activated receptor (PAR-1) that requires N-terminal proteolytic cleavage for activation by its tethered end. A 14-mer thrombin receptor activation peptide (TRAP) of the tethered end induces the same cellular changes as thrombin. Four murine tumor cells (Lewis lung, CT26 colon CA, B16F10 melanoma, and CCL163 fibroblasts) contain PAR-1, as detected by reverse transcriptase-polymerase chain reaction (RT-PCR). B16F10 cells did not contain the two other thrombin receptors, PAR-3 and glycoprotein Ib. TRAP-treated B16F10 tumor cells enhance pulmonary metastasis 41- to 48-fold (n = 17). Thrombin-treated B16F10 cells transfected with full-length murine PAR-1 sense cDNA (S6, S7, S14, and S22) enhanced their adhesion to fibronectin 1.5- to 2.4-fold (n = 5, P < .04), whereas thrombin-treated wild-type cells do not. S6 (adhesion index, 1.5-fold) and S14 (index, 2.4-fold) when examined by RT-PCR and Northern analysis showed minimal expression of PAR-1 for S6 over wild-type and considerable expression for S14. Immunohistochemistry showed greater expression of PAR-1 for S14 compared with wild-type or empty-plasmid transfected cells. In vivo experiments with the thrombin-treated S14 transfectant showed a fivefold to sixfold increase in metastases compared with empty-plasmid transfected thrombin-treated naive cells or S6 cells (n = 20, P = .0001 to .02). Antisense had no effect on thrombin-stimulated tumor mass. Thus, PAR-1 ligation and expression enhances and regulates tumor metastasis.
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24
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Majumdar M, Seasholtz TM, Goldstein D, de Lanerolle P, Brown JH. Requirement for Rho-mediated myosin light chain phosphorylation in thrombin-stimulated cell rounding and its dissociation from mitogenesis. J Biol Chem 1998; 273:10099-106. [PMID: 9553056 DOI: 10.1074/jbc.273.17.10099] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombin treatment causes a dose-dependent rounding of 1321N1 astrocytoma cells. This cytoskeletal response is rapid, peaking 2 h after thrombin stimulation, and reverses by 50% after 24 h. The thrombin receptor peptide SFLLRNP also induces cell rounding, whereas other G protein-linked receptor agonists such as carbachol, lysophosphatidic acid, or bradykinin fail to do so. Results of studies using pharmacological inhibitors do not support a requirement for phosphatidylinositol 3-kinase, mitogen-activated protein kinase, or Ca2+ mobilization in this response. Inhibition of protein kinase C or tyrosine kinase produces minimal blockade. Pertussis toxin treatment is also without effect. However, thrombin-induced rounding is fully blocked by the C3 toxin from Clostridium botulinum, which specifically ADP-ribosylates and inactivates the small G protein Rho. Thrombin also leads to a rapid, 2.4-fold increase in 32P incorporation into myosin light chain while carbachol does not. Myosin phosphorylation, like cell rounding is inhibited by inactivation of Rho with C3 exoenzyme, suggesting that myosin phosphorylation is necessary for this cytoskeletal response. This is supported by the observation that thrombin-induced rounding is also blocked by the myosin light chain kinase inhibitor KT5926. However, treatment with KT5926 fails to inhibit mitogenesis. Thus, cell rounding is not prerequisite to thrombin-induced DNA synthesis. We conclude that stimulation of the heterotrimeric G protein-coupled thrombin receptor in 1321N1 cells activates Rho-dependent pathways for both DNA synthesis and cell rounding, the cytoskeletal response being mediated in part through increases in myosin phosphorylation.
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Affiliation(s)
- M Majumdar
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0636, USA
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25
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Zheng JS, O'Neill L, Long X, Webb TE, Barnard EA, Lakatta EG, Boluyt MO. Stimulation of P2Y receptors activates c-fos gene expression and inhibits DNA synthesis in cultured cardiac fibroblasts. Cardiovasc Res 1998; 37:718-28. [PMID: 9659456 DOI: 10.1016/s0008-6363(97)00245-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVES The aims of this study were to determine (1) whether neonatal rat cardiac fibroblasts (CAFB) express P2Y receptors; (2) whether CAFB respond to extracellular ATP by inducing expression of c-fos mRNA; and (3) whether extracellular ATP modulates norepinephrine (NE)-stimulated cell growth in CAFB. METHODS Expression of P2Y1 and P2Y2 receptors and induction of c-fos were examined by Northern blot analysis. CAFB growth was assessed by measuring [3H]thymidine incorporation and DNA content. P2Y receptor pharmacology was studied using various ATP analogues. RESULTS Northern blot analysis of polyA enriched RNA confirmed that at least 2 subtypes of P2Y receptors (P2Y1 and P2Y2) are expressed in cultured CAFB. Extracellular ATP induced the expression of c-fos mRNA through a pathway that was sensitive to inhibitors of protein kinase C (PKC), but not to inhibitors of intracellular Ca2+ signaling. Extracellular ATP inhibited the NE-stimulated increases in DNA content and in [3H]thymidine incorporation into DNA. Whereas the potency order for stimulation of c-fos expression was ATP = UTP > ADP > adenosine, the potency order to inhibit the NE-induced increase of [3H]thymidine incorporation into DNA was ATP > ADP > UTP > adenosine. CONCLUSIONS These data demonstrate that CAFB express both P2Y1 and P2Y2 receptor mRNA and that CAFB respond to P2Y receptor stimulation by induction of c-fos and inhibition of DNA synthesis. These findings suggest that the effects of ATP on [3H]thymidine incorporation into DNA and on expression of c-fos mRNA are exerted via distinct P2Y receptor subtypes.
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Affiliation(s)
- J S Zheng
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institute of Health, Baltimore, MD 21224, USA
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26
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El-Hefnawy T, Huhtaniemi I. Progesterone can participate in down-regulation of the luteinizing hormone receptor gene expression and function in cultured murine Leydig cells. Mol Cell Endocrinol 1998; 137:127-38. [PMID: 9605514 DOI: 10.1016/s0303-7207(98)00002-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The intratesticular concentration of progesterone (P) rises up to the micromolar range during high-dose luteinizing hormone (LH)/hCG stimulation. The aim of this study was to examine whether P is involved in the concomitant down-regulation of the LH receptor (R) function. The effects were tested in a mouse Leydig tumor cell line (mLTC-1) and in Percoll-purified adult mouse Leydig cells. Pre-incubation of the mLTC-1 cells for 48 h with P (1-10 micromol/l) decreased in dose-dependent fashion their specific binding of [125I]iodo-hCG as well as the hCG-induced cAMP production (down to 65 and 40% respectively, of controls, P < 0.01). Similar effect of P on hCG-induced cAMP production was observed in adult mouse Leydig cells following a 24 h incubation in the presence of P (0.3-10 micromol/l). In addition, P treatment significantly inhibited the expression of a transiently transfected murine LHR promoter (715 or 950 bp of the 5' untranslated region)-luciferase fusion constructs in mLTC-1 cells (down to 50% of control, P < 0.01). In accordance, a 6-12 h culture in the presence of 5-10 micromol/l of P showed significant down-regulatory effects on the steady state levels of LHR-mRNA in mLTC-1 cells. These inhibitory effects of P on the LHR expression and function were mimicked by similar concentrations of cortisol, but not by testosterone or estradiol. Blocking the steroid synthesis of mLTC-1 cells with 86 micromol/l of aminoglutethimide (AMG) partially reversed the down-regulating effect of hCG on the LHR-mRNA. Moreover, a 24 h culture in the presence of AMG showed an up-regulating effect on expression of the LHR promoter-luciferase constructs, and including hCG (50 microg/l) in the culture medium enhanced this effect. Hence, in the absence of steroidogenesis, hCG up-regulates the LHR promoter expression. In conclusion, we present here a novel short-loop regulatory mechanism in murine Leydig cells where P exerts a negative effect on LHR expression and function. Since Leydig cell P production is dramatically increased during high-dose stimulation with LH/hCG, due to blockade of C21 steroid side chain cleavage, the present findings offer a function for this steroid in the LHR down-regulation.
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Affiliation(s)
- T El-Hefnawy
- Department of Physiology, University of Turku, Finland
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27
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Redburn JL, Leah JD. Accelerated breakdown and enhanced expression of c-Fos in the rat brain after noxious stimulation. Neurosci Lett 1997; 237:97-100. [PMID: 9453224 DOI: 10.1016/s0304-3940(97)00820-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
c-Fos expression was examined in rat brains at increasing times after a single noxious stimulus to one hindpaw. In some nuclei the expression peaked at 1 h and was gone by 6 h; in others it was biphasic with a larger peak appearing 6 h after the first. In other rats a second, contralateral stimulus was given at increasing times after the first, and c-Fos examined after a further 1.5 h. In some nuclei the first stimulus potentiated c-Fos expression caused by the second stimulus; in others the second stimulus erased any c-Fos still present from the first. Thus two similar stimuli can interact in very different ways in effecting c-Fos expression in different central nervous system nuclei, and rapid down-regulation might represent a novel type of interaction.
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Affiliation(s)
- J L Redburn
- School of Biomolecular and Biomedical Sciences, Griffith University, Nathan, Australia
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Estus S, Tucker HM, van Rooyen C, Wright S, Brigham EF, Wogulis M, Rydel RE. Aggregated amyloid-beta protein induces cortical neuronal apoptosis and concomitant "apoptotic" pattern of gene induction. J Neurosci 1997; 17:7736-45. [PMID: 9315895 PMCID: PMC6793913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
To gain a molecular understanding of neuronal responses to amyloid-beta peptide (Abeta), we have analyzed the effects of Abeta treatment on neuronal gene expression in vitro by quantitative reverse transcription-PCR and in situ hybridization. Treatment of cultured rat cortical neurons with Abeta1-40 results in a widespread apoptotic neuronal death. Associated with death is an induction of several members of the immediate early gene family. Specifically, we (1) report the time-dependent and robust induction of c-jun, junB, c-fos, and fosB, as well as transin, which is induced by c-Jun/c-Fos heterodimers and encodes an extracellular matrix protease; these gene inductions appear to be selective because other Jun and Fos family members, i.e., junD and fra-1, are induced only marginally; (2) show that the c-jun induction is widespread, whereas c-fos expression is restricted to a subset of neurons, typically those with condensed chromatin, which is a hallmark of apoptosis; (3) correlate gene induction and neuronal death by showing that each has a similar dose-response to Abeta; and (4) demonstrate that both cell death and immediate early gene induction are dependent on Abeta aggregation state. This overall gene expression pattern during this "physiologically inappropriate" apoptotic stimulus is markedly similar to the pattern we previously identified after a "physiologically appropriate" stimulus, i.e., the NGF deprivation-induced death of sympathetic neurons. Hence, the parallels identified here further our understanding of the genetic alterations that may lead neurons to apoptosis in response to markedly different insults.
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Affiliation(s)
- S Estus
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky 40536, USA
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29
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Duhamel-Clérin E, Orvain C, Lanza F, Cazenave JP, Klein-Soyer C. Thrombin receptor-mediated increase of two matrix metalloproteinases, MMP-1 and MMP-3, in human endothelial cells. Arterioscler Thromb Vasc Biol 1997; 17:1931-8. [PMID: 9351356 DOI: 10.1161/01.atv.17.10.1931] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Matrix metalloproteinases (MMPs) are responsible for the degradation of extracellular matrix components and are secreted by a variety of cells including human endothelial cells. Because alpha-thrombin is known to interact with matrix components and has been shown to activate latent MMP-2 in human umbilical vein endothelial cells, we investigated whether human alpha-thrombin could also regulate other MMPs secreted by the human saphenous vein or mammary artery endothelial cells (EC). After treatment of EC with increasing concentrations of thrombin for different periods of time, a significantly higher gelatinolytic activity of both MMP-1 and MMP-3 was observed in addition to MMP-2 activation. The effect of thrombin was time and dose-dependent, reaching a maximum at 24 hours. After treatment with 5 NIH U/ml thrombin for 24 hours, Western blotting revealed 9.5- and 4.4-fold increases over control values for MMP-3 and MMP-1, respectively. The synthetic thrombin receptor agonist peptide SFLLRNPNDKYEPF fully reproduced the action of thrombin, whereas chemical inactivation of the catalytic site of thrombin abolished its effect on MMP-1 and MMP-3. Thrombin and SFLLRNPNDKYEPF both induced MMP-3 mRNA synthesis but had no significant influence on constitutive MMP-1 mRNA levels. These results demonstrate that thrombin not only activates latent MMP-2 but also modulates MMP-1 and MMP-3 production in EC, this latter effect being mediated by the G-protein-coupled thrombin receptor. Hence, our present data provide evidence to support the suspected role of thrombin in tissue remodeling and angiogenesis.
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Affiliation(s)
- E Duhamel-Clérin
- INSERM U. 311, Establissement de Transfusion Sanguine de Strasbourg, France
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30
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Heller Brown J, Sah V, Moskowitz S, Ramirez T, Collins L, Post G, Goldstein D. Pathways and roadblocks in muscarinic receptor-mediated growth regulation. Life Sci 1997. [DOI: 10.1016/s0024-3205(97)00050-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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31
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Cohen RI, Molina-Holgado E, Almazan G. Carbachol stimulates c-fos expression and proliferation in oligodendrocyte progenitors. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1996; 43:193-201. [PMID: 9037533 DOI: 10.1016/s0169-328x(96)00176-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To determine if muscarinic receptor-activation plays a role in oligodendrocyte development, the effect of carbachol a stable acetylcholine analog, on gene expression and proliferation was investigated. Using Northern blot analysis we showed that carbachol caused a time and concentration-dependent increase in c-fos mRNA. This effect was blocked by atropine, a non-selective muscarinic antagonist. In addition, the muscarinic-stimulated c-fos increase was inhibited by 1-(5-isoquinoline-sulfonyl)-2-methylpiperazine (H-7), a potent inhibitor of protein kinase C (PKC), but not by N-2-(p-bromocinnamylamino)-ethyl-5-isoquinoline-sulfonamide (H-89), a potent inhibitor of protein kinase A, suggesting the involvement of PKC in mediating the response. Down-regulation of PKC by overnight pre-treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) blocked only the phorbol ester-stimulated c-fos accumulation while no effect was observed in the carbachol-induced response. These results suggested that carbachol stimulated an H-7 sensitive PKC pathway which may be different than that activated by TPA. Further evidence for two separate mechanisms of proto-oncogene induction was provided by the additive effect of carbachol and TPA. Induction of c-fos mRNA by carbachol was dependent on both influx of extracellular Ca2+ and release from intracellular stores, as both EDTA and BAPTA blocked the response. Since activation of muscarinic receptors can affect cell division in other cellular systems, the effect of carbachol on [3H]thymidine and bromodeoxyuridine incorporation into oligodendrocyte DNA was measured. Carbachol stimulated DNA synthesis in oligodendrocyte progenitors. This effect was mediated by muscarinic receptors as [3H]thymidine incorporation was prevented or significantly reduced by the addition of atropine. In conclusion, the present findings suggest that, the neurotransmitter, acetylcholine may act as a trophic factor in developing oligodendrocytes, regulating their growth and development in the central nervous system.
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Affiliation(s)
- R I Cohen
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Que., Canada
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32
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Geimonen E, Jiang W, Ali M, Fishman GI, Garfield RE, Andersen J. Activation of protein kinase C in human uterine smooth muscle induces connexin-43 gene transcription through an AP-1 site in the promoter sequence. J Biol Chem 1996; 271:23667-74. [PMID: 8798588 DOI: 10.1074/jbc.271.39.23667] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Myometrial connexin-43 gap junctions are scarce throughout gestation but appear in large numbers at term to facilitate contractions during labor. The mechanisms that regulate this process are incompletely characterized. This report investigates the effects of protein kinase C activation on the regulation of connexin-43 gene transcription in human uterine smooth muscle cells. In primary myometrial cells treated with phorbol ester, transient increases in c-Fos and c-Jun protein levels were observed at 2-4 h, followed by significant increases in connexin-43 protein levels at 6-8 h. Nuclear run-on transcription analysis showed an increase in connexin-43 transcription 3 h after phorbol ester treatment. AP-1 sites were identified in the sequence of the 5'-flanking promoter region of the human connexin-43 gene at 44 and 1000 base pairs upstream of transcription start. Transcription from a reporter plasmid containing the proximal human connexin-43 promoter was increased in transfected primary cultures treated with phorbol ester. Mutation of the proximal AP-1 site in the promoter abolished the phorbol ester-dependent transactivation. This work provides evidence that transcription of the human connexin-43 gene is induced through protein kinase C activation in uterine smooth muscle cells, and that the induction involves up-regulation and activation of c-Jun and c-Fos.
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Affiliation(s)
- E Geimonen
- Department of Obstetrics, Gynecology and Reproductive Medicine, School of Medicine, State University of New York, Stony Brook, New York 11794-8091, USA
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Collins LR, Minden A, Karin M, Brown JH. Galpha12 stimulates c-Jun NH2-terminal kinase through the small G proteins Ras and Rac. J Biol Chem 1996; 271:17349-53. [PMID: 8663428 DOI: 10.1074/jbc.271.29.17349] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The pertussis toxin (PTX) insensitive heterotrimeric G protein G12 has been implicated in mitogenesis and transformation, but its direct effectors remain unknown. To define potential signaling pathways utilized by G12, we expressed an activated mutant of its alpha subunit, Galpha12(Q229L), in HEK293 cells and examined its effects on Ras and mitogen-activated protein kinases (MAPKs). Transient expression of activated Galpha12 increased the percentage of Ras in the active, GTP-bound state, stimulated c-Jun NH2-terminal kinase (JNK) activity, and enhanced the transcriptional activity of c-Jun. Dominant negative Ras (N17Ras) inhibited Galpha12-mediated JNK activation in NIH3T3 cells but failed to do so in HEK293 cells. In contrast, dominant negative Rac (N17Rac1) inhibited JNK activation by Galpha12 in HEK293 cells as well as three other cell lines. In 1321N1 cells, where thrombin stimulates G12-dependent mitogenesis, coexpression of N17Rac1 or a dominant negative mutant of MEKK1 (MEKKDelta(K432M)) inhibits c-Jun/AP-1 sensitive reporter gene expression stimulated by thrombin or Galpha12. These data demonstrate that the alpha subunit of the heterotrimeric G protein G12, like tyrosine kinase growth factor receptors, activates Ras and recruits a signal transduction pathway involving the small GTP-binding protein Rac that leads to JNK activation.
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Affiliation(s)
- L R Collins
- Department of Pharmacology, University of California at San Diego, La Jolla, California 92093-0636, USA
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34
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Winking M, Heldt RM, Simmet T. Thrombin stimulates activation of the cerebral 5-lipoxygenase pathway during blood-brain cell contact. J Cereb Blood Flow Metab 1996; 16:737-45. [PMID: 8964815 DOI: 10.1097/00004647-199607000-00026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The purpose of this study was to identity the trigger mechanism activating the 5-lipoxygenase pathway during blood-brain cell contact and to estimate the contribution of blood and brain cells to the cysteinyl-leukotriene (LT) biosynthesis observed under these conditions. Incubation of dissociated rat brain cells in Krebs-Henseleit solution for up to 60 min did not stimulate any detectable cysteinyl-LT biosynthesis. Incubation of recalcified rat whole blood in vitro for up to 60 min led to release of only small amounts of cysteinyl-LT into the serum samples. However, coincubation of dissociated rat brain cells with physiologically recalcified autologous whole blood triggered a time-dependent release of large amounts of immunoreactive cysteinyl-LT into the serum samples. By reverse-phase HPLC, immunoreactive cysteinyl-LT was identified as a mixture of LTC4, LTD4, and LTE4. The extent of the 5-lipoxygenase stimulation depended on the amount of autologous blood coincubated with the dissociated brain cells. Activation of the 5-lipoxygenase pathway also occurred with coincubation of dissociated rat brain cells with recalcified autologous plasma. Stimulation of cysteinyl-LT biosynthesis during blood-brain cell contact remained unaffected by aprotinin, but concentration-dependent inhibition by the structurally and functionally unrelated thrombin inhibitors D-Phe-Pro-Arg-CH2Cl and recombinant hirudin was seen. Finally, when dissociated rat brain cells were incubated in Krebs-Henseleit solution in the presence of human alpha-thrombin, a concentration-dependent release of cysteinyl-LT into the buffer samples was observed. These data demonstrate that, in rats, during blood-brain cell contact, stimulation of the 5-lipoxygenase pathway in brain cells proceeds via alpha-thrombin as effector molecule.
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Affiliation(s)
- M Winking
- Division of Neurosurgery, Justus-Liebig University, Giessen, Germany
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35
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Zheng JS, Boluyt MO, Long X, O'Neill L, Lakatta EG, Crow MT. Extracellular ATP inhibits adrenergic agonist-induced hypertrophy of neonatal cardiac myocytes. Circ Res 1996; 78:525-35. [PMID: 8635209 DOI: 10.1161/01.res.78.4.525] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have previously shown that extracellular ATP, like norepinephrine (NE) and many other hypertrophy-inducing agents, increases expression of the immediate-early genes c-fos and junB in cultured neonatal cardiac myocytes but that the intracellular signaling pathways activated by ATP and responsible for these changes differ from those stimulated by NE. Furthermore, whereas NE increases incorporation of [14C]phenylalanine (14C-Phe) and cell size in neonatal cardiomyocytes, ATP does not. Since ATP is coreleased with NE from sympathetic nerve endings in the heart, we investigated whether ATP could modulate cardiac hypertrophy induced by adrenergic agonists, such as NE. We report in the present study that extracellular ATP inhibited the increase in incorporation of 14C-Phe into cellular protein and the increase in cell size in neonatal rat cardiac myocytes that was induced by NE, phenylephrine (PE), basic fibroblast growth factor, or endothelin-1. This inhibition was dose dependent, occurred predominantly through P2 purinergic receptors, and was observed even when cells were treated with ATP for as little as 1 hour before the addition of the hypertrophy-inducing agent. ATP also selectively affected changes in gene expression associated with hypertrophy. It prevented PE-stimulated increases in atrial natriuretic factor and myosin light chain-2 mRNA levels, while appearing to augment basal and PE-stimulated skeletal alpha-actin mRNA levels. ATP alone increased sarcoplasmic reticulum Ca2+-ATPase mRNA levels but had no effect when added with PE. ATP did not significantly affect the level of the constitutively expressed mRNA for GAPDH. Neither the PE-stimulated increase in immediate-early gene expression nor the initial induction of mitogen-activated protein kinase activity by PE was inhibited by ATP. These results demonstrate that extracellular ATP can inhibit hypertrophic growth of neonatal cardiac myocytes and differentially alter the changes in gene expression that accompany hypertrophy.
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Affiliation(s)
- J S Zheng
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
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36
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Jiang T, Kuznetsov V, Pak E, Zhang H, Robinson RB, Steinberg SF. Thrombin receptor actions in neonatal rat ventricular myocytes. Circ Res 1996; 78:553-63. [PMID: 8635212 DOI: 10.1161/01.res.78.4.553] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Previous studies established that thrombin stimulates phosphoinositide hydrolysis and modulates contractile function in neonatal rat ventricular myocytes. The present study further defines the signaling pathways activated by the thrombin receptor and their role in thrombin's actions in cardiac myocytes. The thrombin receptor-derived agonist peptide (TRAP, a portion of the tethered ligand created by thrombin's proteolytic activity) stimulates the rapid and transient accumulation of inositol bis- and tris-phosphates (IP2 and IP3, respectively), which is followed by the more gradual and sustained accumulation of inositol monophosphate (IP1). TRAP elicits a larger and more sustained accumulation of IP1 than does thrombin. Thrombin and TRAP also activate mitogen-activated protein kinase (MAPK) in cultured neonatal rat ventricular myocytes. Differences in the kinetics and magnitude of thrombin- and TRAP-dependent inositol phosphate (IP) accumulation are paralleled by differences in the kinetics and magnitude of thrombin- and TRAP-dependent activation of MAPK. Pretreatment with phorbol 12-myristate 13-acetate (PMA) to downregulate protein kinase C (PKC) attenuates thrombin- and TRAP-dependent activation of MAPK, although small and equivalent effects of thrombin and TRAP to stimulate MAPK persist in PMA-pretreated cells. These results support the notion that the thrombin receptor activates MAPK through PKC-dependent pathways and that the incremental activation of MAPK by TRAP over that induced by thrombin is the consequence of enhanced activation through the PKC limb of the phosphoinositide lipid pathway. TRAP also increases the beating rate of spontaneously contracting ventricular myocytes and elevates cytosolic calcium in myocytes electrically driven at a constant basic cycle length. The effects of TRAP to modulate contractile function and elevate intracellular calcium are not inhibited by tricyclodecan-9-yl-xanthogenate (D609, to block TRAP-dependent IP accumulation) or pretreatment with PMA (to downregulate PKC). The TRAP-dependent rise in intracellular calcium also is not inhibited by verapamil or removal of extracellular calcium but is markedly attenuated by depletion of sarcoplasmic reticular calcium stores by caffeine. Patch-clamp experiments demonstrate that TRAP elevates intracellular calcium in cells held at a membrane potential of -70 mV. Taken together, these results support the conclusion that the thrombin receptor modulates contractile function by mobilizing intracellular calcium through an IP3-independent mechanism and that this response does not require activation of voltage-gated ion channels.
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Affiliation(s)
- T Jiang
- Department of Medicine, Columbia University, New York 10032, USA
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37
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Dewji NN, Do C, Bayney RM. Transcriptional activation of Alzheimer's beta-amyloid precursor protein gene by stress. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1995; 33:245-53. [PMID: 8750883 DOI: 10.1016/0169-328x(95)00131-b] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A neuropathological hallmark of Alzheimer's disease (AD) is the neuritic plaque, composed of an extracellular cluster of degenerating nerve terminals with a central core that is in part composed of deposits of a 4 kDa beta-amyloid peptide. Over-expression of the amyloid precursor protein (beta-APP) gene could be a contributing factor in the aberrant processing of the precursor protein, possibly leading to the formation of beta-amyloid. In AD the brain exhibits several features which indicate that neurons affected by AD exist under conditions of stress. Although the heat shock consensus sequence (CTCGACTTTTCTAG) located at position -317 bp is among the regulatory elements of the beta-APP gene, suggesting that this may act in the regulation of the beta-APP gene in response to stress, an induction of beta-APP as a result of interaction of this element with a heat shock factor has so far not been demonstrated. Moreover, there are conflicting reports in the literature regarding the up-regulation of beta-APP with stress. In this study we have used a fragment of the beta-APP promoter which includes the heat shock element, cloned into a luciferase expression vector pxP2 to transiently transfect cultured human NT2 and HeLa cells. Our findings directly demonstrate that transcription of the beta-APP gene is stimulated by various stresses--increase in temperature, treatment with ethanol and sodium arsenite. Gel mobility shift assays confirm the interaction of the heat shock element with a heat shock factor, induced as a result of stress.
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Affiliation(s)
- N N Dewji
- Department of Medicine, University of California at San Diego, La Jolla 92093, USA
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38
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Aragay AM, Collins LR, Post GR, Watson AJ, Feramisco JR, Brown JH, Simon MI. G12 requirement for thrombin-stimulated gene expression and DNA synthesis in 1321N1 astrocytoma cells. J Biol Chem 1995; 270:20073-7. [PMID: 7650024 DOI: 10.1074/jbc.270.34.20073] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Thrombin stimulation of 1321N1 astrocytoma cells leads to Ras-dependent AP-1-mediated transcriptional activation and to DNA replication. In contrast to what has been observed in most cell systems, in 1321N1 cells these responses are pertussis toxin-insensitive. The pertussis toxin-insensitive G-protein G12 has been implicated in cell growth and transformation in different cell systems. We have examined the potential role of this protein in AP-1-mediated transcriptional activation and DNA synthesis in 1321N1 cells. Transient expression of an activated (GTPase-deficient) mutant of G alpha 12 increased AP-1-dependent gene expression. This response was inhibited by co-expression of a dominant negative Ala-15 Ras protein. To determine whether the pertussis toxin-insensitive G12 protein is involved in the thrombin-stimulated DNA synthesis, an inhibitory antibody against the C-terminal sequence of G alpha 12 subunit was microinjected into 1321N1 cells. Microinjection of the anti-G alpha 12 resulted in a concentration-dependent inhibition of thrombin-stimulated DNA synthesis. In contrast, microinjection of nonimmune IgG or an antibody directed against the C terminus of G alpha o did not reduce the mitogenic response to thrombin. Furthermore, microinjection of the anti-G alpha 12 antibody had no effect on fibroblast growth factor-stimulated DNA synthesis. These results demonstrate a specific role for G alpha 12 in the mitogenic response to thrombin in human astroglial cells.
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Affiliation(s)
- A M Aragay
- Division of Biology, California Institute of Technology, Pasadena 91125, USA
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39
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Dragunow M, Preston K. The role of inducible transcription factors in apoptotic nerve cell death. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1995; 21:1-28. [PMID: 8547952 DOI: 10.1016/0165-0173(95)00003-l] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Recent studies have shown that certain types of nerve cell death in the brain occur by an apoptotic mechanism. Researchers have demonstrated that moderate hypoxic-ischemic (HI) episodes and status epilepticus (SE) can cause DNA fragmentation as well as other morphological features of apoptosis in neurons destined to die, whereas more severe HI episodes lead to neuronal necrosis and infarction. Although somewhat controversial, some studies have demonstrated that protein synthesis inhibition prevents HI-and SE-induced nerve cell death in the brain, suggesting that apoptotic nerve cell death in the adult brain is de novo protein synthesis-dependent (i.e., programmed). The identity of the proteins involved in HI-and SE-induced apoptosis in the adult brain is unclear, although based upon studies in cell culture, a number of potential cell death and anti-apoptosis genes have been identified. In addition, a number of studies have demonstrated that inducible transcription factors (ITFs) are expressed for prolonged periods in neurons undergoing apoptotic death following HI and SE. These results suggest that prolonged expression of ITFs (in particular c-jun) may form part of the biological cascade that induces apoptosis in adult neurons. These various studies are critically discussed and in particular the role of inducible transcription factors in neuronal apoptosis is evaluated.
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Affiliation(s)
- M Dragunow
- Department of Pharmacology and Clinical Pharmacology, School of Medicine, University of Auckland, New Zealand
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40
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Rezzonico R, Ponzio G, Loubat A, Lallemand D, Proudfoot A, Rossi B. Two distinct signalling pathways are involved in the control of the biphasic junB transcription induced by interleukin-6 in the B cell hybridoma 7TD1. J Biol Chem 1995; 270:1261-8. [PMID: 7836389 DOI: 10.1074/jbc.270.3.1261] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have measured the level of junB mRNA in the B hybridoma cell line 7TD1, under interleukin-6 (IL-6) stimulation. IL-6 increases junB mRNA in a biphasic fashion. The first early-induced peak was transient and likely corresponds to the well documented typical junB mRNA, stimulated in response to numerous growth factors, including IL-6. At variance, the second peak which has never been reported previously, lasted several hours. As a consequence of its effect on junB mRNA, IL-6 stimulated, in a biphasic fashion, the nuclear accumulation of the JunB protein. In this study, we demonstrated that IL-6 regulation occurred exclusively at the transcriptional level and that the bimodal increase of junB mRNA and JunB protein can be accounted for by a biphasic stimulation of junB transcription. Furthermore, our data point to two major differences between the mechanism of control of the early and the late IL-6-induced junB transcription waves. First, cycloheximide strongly potentiated the transcription of the second wave, whereas it failed to affect the early-induced burst. Second, tyrphostin, a tyrosine kinase inhibitor, impaired the expression of the first but not the second junB mRNA peak. Conversely, genistein, another tyrosine kinase inhibitor, totally abolished the expression of the second peak of junB mRNA whereas it did not affect the expression of the first peak. Altogether these data indicate that, in 7TD1 cells, IL-6 controls junB transcription in a biphasic fashion by means of two separate transduction pathways.
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Affiliation(s)
- R Rezzonico
- INSERM U364, Faculté de Médecine, Nice, France
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41
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Stratowa C, Himmler A, Czernilofsky AP. Use of a luciferase reporter system for characterizing G-protein-linked receptors. Curr Opin Biotechnol 1995. [DOI: 10.1016/0958-1669(95)80095-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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42
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A direct role for protein kinase C and the transcription factor Jun/AP-1 in the regulation of the Alzheimer's beta-amyloid precursor protein gene. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31860-4] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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43
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Hughes P, Dragunow M. Activation of pirenzepine-sensitive muscarinic receptors induces a specific pattern of immediate-early gene expression in rat brain neurons. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1994; 24:166-78. [PMID: 7968354 DOI: 10.1016/0169-328x(94)90129-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Accumulating evidence suggests that immediate-early gene transcription factors such as c-Fos, form part of an intracellular signalling pathway linking the activation of neuronal receptors by neurotransmitters to changes in neuronal gene expression. Recently it has been demonstrated that the centrally active muscarinic receptor agonist pilocarpine induces both c-fos mRNA and protein in rat brain. In this report using immunocytochemical and in situ hybridization techniques we demonstrate for the first time that in addition to c-fos, pilocarpine administration increases the neuronal expression of jun-B, krox-20 and krox-24 (zif-268) but not related c-jun and jun-D genes in rat cortex and hippocampus. Pretreatment of animals with atropine or pirenzepine significantly reduced induction of c-fos, jun-B, krox-20 and krox-24 genes in both hippocampus and cortex. These results show that activation of pirenzepine-sensitive muscarinic receptors results in a specific pattern of immediate-early gene expression in rat brain neurons. We suggest that the combinatorial complexity of immediate-early gene induction may allow receptor-specific control of gene expression in vivo.
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Affiliation(s)
- P Hughes
- Department of Pharmacology and Clinical Pharmacology, School of Medicine, University of Auckland, New Zealand
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44
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Identification of a TPA-responsive element mediating preferential transactivation of the galanin gene promoter in chromaffin cells. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37450-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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45
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Mari B, Imbert V, Belhacene N, Far D, Peyron J, Pouysségur J, Van Obberghen-Schilling E, Rossi B, Auberger P. Thrombin and thrombin receptor agonist peptide induce early events of T cell activation and synergize with TCR cross-linking for CD69 expression and interleukin 2 production. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37225-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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46
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Rosenzweig SA, Oemar BS, Law NM, Shankavaram UT, Miller BS. Insulin like growth factor 1 receptor signal transduction to the nucleus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1994; 343:159-68. [PMID: 8184736 DOI: 10.1007/978-1-4615-2988-0_16] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The mechanism by which IGF-1Rs regulate the growth and maintenance of cells in normal and disease states provides an important setting for studies addressing signal transduction events at the nuclear level. With the identification of c-Jun/AP-1 as a nuclear target of IGF-1 action we are provided with a model system for pursuing the molecular mechanisms triggered by IGF-1 action.
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Affiliation(s)
- S A Rosenzweig
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston 29425
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47
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LaMorte V, Kennedy E, Collins L, Goldstein D, Harootunian A, Brown J, Feramisco J. A requirement for Ras protein function in thrombin-stimulated mitogenesis in astrocytoma cells. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)36530-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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48
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Kitazumi K, Tasaka K. The role of c-Jun protein in thrombin-stimulated expression of preproendothelin-1 mRNA in porcine aortic endothelial cells. Biochem Pharmacol 1993; 46:455-64. [PMID: 8347169 DOI: 10.1016/0006-2952(93)90522-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Treatment of porcine aortic endothelial cells with thrombin induced a time- and dose-dependent expression of preproendothelin-1 (PPET-1) mRNA. The thrombin-induced expression of PPET-1 mRNA was markedly inhibited by calphostin C, a specific inhibitor of protein kinase C, and phorbol 12-myristate 13-acetate (TPA) induced the expression of PPET-1 mRNA dose-dependently, but 4 alpha-phorbol 12, 13-didecanoate, an inactive enantiomer of phorbol ester, had no effect on the expression of PPET-1 mRNA. On the other hand, challenge of the endothelial cells with thrombin induced a marked and time-dependent increase in the binding activity of nuclear extract to the TPA-responsive element. Furthermore, thrombin elicits synthesis of c-Jun protein as well as triggering its dephosphorylation. From these results, it is concluded that thrombin-stimulated expression of PPET-1 mRNA in porcine aortic endothelial cells can be induced not only by c-Jun protein synthesis but also by initial dephosphorylation in response to activation of protein kinase C.
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Affiliation(s)
- K Kitazumi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Okayama University, Japan
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