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Kardas G, Daszyńska-Kardas A, Marynowski M, Brząkalska O, Kuna P, Panek M. Role of Platelet-Derived Growth Factor (PDGF) in Asthma as an Immunoregulatory Factor Mediating Airway Remodeling and Possible Pharmacological Target. Front Pharmacol 2020; 11:47. [PMID: 32116722 PMCID: PMC7033439 DOI: 10.3389/fphar.2020.00047] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/14/2020] [Indexed: 12/22/2022] Open
Abstract
Asthma is a chronic and heterogenic disease of the respiratory system, one of the most common lung diseases worldwide. The underlying pathologies, which are chronic inflammatory process and airway remodeling (AR), are mediated by numerous cells and cytokines. Particularly interesting in this field is the platelet-derived growth factor (PDGF), one of the members of the human growth factor family. In this article, the authors analyze the available data on the role of PDGF in asthma in experimental models and in human research. PDGF is expressed in airway by various cells contributing to asthma pathogenesis—mast cells, eosinophils, and airway epithelial cells. Research confirms the thesis that this factor is also secreted by these cells in the course of asthma. The main effects of PDGF on bronchi are the proliferation of airway smooth muscle (ASM) cells, migration of ASM cells into the epithelium and enhanced collagen synthesis by lung fibroblasts. The importance of AR in asthma is well recognized and new therapies should also aim to manage it, possibly targeting PDGFRs. Further studies on new and already existing drugs, mediating the PDGF signaling and related to asthma are necessary. Several promising drugs from the tyrosine kinase inhibitors group, including nilotinib, imatinib masitinib, and sunitinib, are currently being clinically tested and other molecules are likely to emerge in this field.
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Affiliation(s)
- Grzegorz Kardas
- Clinic of Internal Diseases, Asthma and Allergy, Medical University of Lodz, Łódź, Poland
| | | | - Mateusz Marynowski
- Clinic of Internal Diseases, Asthma and Allergy, Medical University of Lodz, Łódź, Poland
| | - Oliwia Brząkalska
- Clinic of Internal Diseases, Asthma and Allergy, Medical University of Lodz, Łódź, Poland
| | - Piotr Kuna
- Clinic of Internal Diseases, Asthma and Allergy, Medical University of Lodz, Łódź, Poland
| | - Michał Panek
- Clinic of Internal Diseases, Asthma and Allergy, Medical University of Lodz, Łódź, Poland
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2
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Ariga T. Pathogenic role of ganglioside metabolism in neurodegenerative diseases. J Neurosci Res 2014; 92:1227-42. [PMID: 24903509 DOI: 10.1002/jnr.23411] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 04/09/2014] [Accepted: 04/09/2014] [Indexed: 12/13/2022]
Abstract
Ganglioside metabolism is altered in several neurodegenerative diseases, and this may participate in several events related to the pathogenesis of these diseases. Most changes occur in specific areas of the brain and their distinct membrane microdomains or lipid rafts. Antiganglioside antibodies may be involved in dysfunction of the blood-brain barrier and disease progression in these diseases. In lipid rafts, interactions of glycosphingolipids, including ganglioside, with proteins may be responsible for the misfolding events that cause the fibril and/or aggregate processing of disease-specific proteins, such as α-synuclein, in Parkinson's disease, huntingtin protein in Huntington's disease, and copper-zinc superoxide dismutase in amyotrophic lateral sclerosis. Targeting ganglioside metabolism may represent an underexploited opportunity to design novel therapeutic strategies for neurodegeneration in these diseases.
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Affiliation(s)
- Toshio Ariga
- Institute of Molecular Medicine and Genetics, Institute of Neuroscience, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
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3
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Weber AA, Schrör K. The significance of platelet-derived growth factors for proliferation of vascular smooth muscle cells. Platelets 2010. [DOI: 10.1080/09537109909169169] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Wan Nar Wong M, Lui WT, Chuen Fu S, Man Lee K. The effect of glucocorticoids on tendon cell viability in human tendon explants. Acta Orthop 2009; 80:363-7. [PMID: 19421908 PMCID: PMC2823211 DOI: 10.3109/17453670902988386] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND AND PURPOSE Previous studies on the culture of human tenocytes have shown that dexamethasone and triamcinolone reduce cell viability, suppress cell proliferation, and reduce collagen synthesis. However, such cell cultures lack the extracellular matrix and three-dimensional structure of normal tendons, which affects their response to stimuli. We established a human tendon explant culture system and tested the effects of dexamethasone and triamcinolone on cell viability. METHODS Primary human tendon explant cultures were prepared from healthy hamstring tendons. Tendon strips were harvested from hamstring tendons and cultured in 24-well plates in Dulbecco's modification of Eagle's Medium (DMEM) supplemented with 2% fetal calf serum. The tendon explants were treated with 0 microM (control), 10 microM, or 100 microM dexamethasone sodium phosphate or 0 microM (control), 10 microM, or 100 microM triamcinolone acetonide in DMEM for 96 h. Cell viability was measured by Alamar blue assay before and after glucocorticoid treatment. RESULTS Incubation with 10 microM and 100 microM dexamethasone reduced cell viability in human tendon explants by 35% and 45%, respectively, as compared to a 6% increase in the controls (p = 0.01, mixed-effects ANOVA). Triamcinolone at 10 microM and 100 microM reduced cell viability by 33% and 36%, respectively, as compared to a 9% increase in the controls (p = 0.07, mixed-effects ANOVA). INTERPRETATION Human tendon explant cultures can be used to study the effects of glucocorticoids on human tendon. Dexamethasone and triamcinolone suppress the cell viability of human tendon in its natural 3-dimensional environment with matrix anchorage. Human tendon explant cultures provide a species-specific model for further investigation of the effects of glucocorticoids on the metabolism of the extracellular matrix of human tendon, and on its mechanical properties.
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Affiliation(s)
| | - Wai Ting Lui
- 1Department of Orthopaedics, Traumatology Shatin,ShatinHong Kong
| | - Sai Chuen Fu
- 1Department of Orthopaedics, Traumatology Shatin,ShatinHong Kong
| | - Kwong Man Lee
- 2Lee Hysan Clinical Research Laboratories,, Chinese University of Hong KongShatinHong Kong
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5
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Hadoke PWF, Iqbal J, Walker BR. Therapeutic manipulation of glucocorticoid metabolism in cardiovascular disease. Br J Pharmacol 2009; 156:689-712. [PMID: 19239478 DOI: 10.1111/j.1476-5381.2008.00047.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The therapeutic potential for manipulation of glucocorticoid metabolism in cardiovascular disease was revolutionized by the recognition that access of glucocorticoids to their receptors is regulated in a tissue-specific manner by the isozymes of 11beta-hydroxysteroid dehydrogenase. Selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 have been shown recently to ameliorate cardiovascular risk factors and inhibit the development of atherosclerosis. This article addresses the possibility that inhibition of 11beta-hydroxsteroid dehydrogenase type 1 activity in cells of the cardiovascular system contributes to this beneficial action. The link between glucocorticoids and cardiovascular disease is complex as glucocorticoid excess is linked with increased cardiovascular events but glucocorticoid administration can reduce atherogenesis and restenosis in animal models. There is considerable evidence that glucocorticoids can interact directly with cells of the cardiovascular system to alter their function and structure and the inflammatory response to injury. These actions may be regulated by glucocorticoid and/or mineralocorticoid receptors but are also dependent on the 11beta-hydroxysteroid dehydrogenases which may be expressed in cardiac, vascular (endothelial, smooth muscle) and inflammatory (macrophages, neutrophils) cells. The activity of 11beta-hydroxysteroid dehydrogenases in these cells is dependent upon differentiation state, the action of pro-inflammaotory cytokines and the influence of endogenous inhibitors (oxysterols, bile acids). Further investigations are required to clarify the link between glucocorticoid excess and cardiovascular events and to determine the mechanism through which glucocorticoid treatment inhibits atherosclerosis/restenosis. This will provide greater insights into the potential benefit of selective 11beta-hydroxysteroid dehydrogenase inhibitors in treatment of cardiovascular disease.
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Affiliation(s)
- Patrick W F Hadoke
- Centre for Cardiovascular Sciences, University of Edinburgh, The Queen's Medical Research Institute, Edinburgh, UK.
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6
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Ivey ME, Osman N, Little PJ. Endothelin-1 signalling in vascular smooth muscle: pathways controlling cellular functions associated with atherosclerosis. Atherosclerosis 2008; 199:237-47. [PMID: 18436225 DOI: 10.1016/j.atherosclerosis.2008.03.006] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 03/04/2008] [Accepted: 03/10/2008] [Indexed: 12/16/2022]
Abstract
Atherosclerosis is the primary ischaemic vascular condition underlying a majority of cardiovascular disease related deaths. Endothelin-1 is a vasoactive peptide agent upregulated in atherosclerosis and in conjunction with its G protein-coupled receptors exerts diverse actions on all cells of the vasculature in particular vascular smooth muscle cells (VSMC). The effects of endothelin-1 include cell proliferation, migration and contraction, and the induction of extracellular matrix components and growth factors. VSMC as the major component of the neointima in atherosclerotic plaques accordingly play a key role in atherogenesis. In this review we examine classic and novel signalling pathways activated by endothelin-1 in VSMC (including phospholipase C, adenylate cyclase, Rho kinase, transactivation of receptor tyrosine kinases, mitogen activated protein kinase cascades and beta-arrestin) and their likely impact on the development and progression of atherosclerosis.
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Affiliation(s)
- Melanie E Ivey
- Cell Biology of Diabetes Laboratory, Baker Heart Research Institute, Melbourne, Victoria, Australia
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7
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Zhang W, Zhang Y, Edvinsson L, Xu CB. Up-regulation of thromboxane A2 receptor expression by lipid soluble smoking particles through post-transcriptional mechanisms. Atherosclerosis 2008; 196:608-16. [PMID: 17706224 DOI: 10.1016/j.atherosclerosis.2007.06.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 06/23/2007] [Accepted: 06/25/2007] [Indexed: 12/12/2022]
Abstract
Atherosclerosis is a key factor in vascular disease, and cigarette smoking is a well-known risk factor that may induce an inflammatory response and enhance plaque formation in arteries. Thromboxane (Tx) is one key inflammatory mediator involved in the pathogenesis of cardiovascular disease. The present study was designed to test if lipid soluble smoking particles (DSP) enhance TxA(2) receptor (TP) expression in rat mesenteric arteries, and if intracellular mitogen-activated protein kinase (MAPK) pathways play a role. Organ culture of rat mesenteric arteries in the presence of DSP (0.2 microl/ml for 24h) resulted in markedly elevated contractile responses to the Tx analog U46619, compared with the control DMSO. There was no increase in TP receptor mRNA expression, while the protein expression was significantly enhanced. This up-regulation was not affected by a general transcriptional inhibitor actinomycin D, but was almost completely abolished by cycloheximide, a general translational inhibitor. Dexamethasone, a glucocorticoid, manifested a potent inhibitory effect as well. These results suggest that the up-regulation of TP receptor occurs via post-transcriptional events, and mainly translation. This is supported by experiments with specific inhibitors for c-Jun-NH(2)-terminal kinase (SP600125), extracellular signal-regulated kinase 1 and 2 (PD98059 and U0126) and p38 (SB203580) that had no inhibitory effect on the up-regulation of TP receptors. Collectively, the results show that MAPK pathways are not involved in TP receptor up-regulation. Study on TP receptor mRNA stability showed that during organ culture, the TP receptor mRNA was stable in both DMSO and DSP group, but the latter elicited a tendency to stabilize the TP receptor mRNA at higher level. Thus, post-transcriptional mechanisms are responsible for the up-regulation of TP receptor by DSP, in which enhanced translation is the major cause of the elevated protein expression and the enhanced contraction.
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Affiliation(s)
- Wei Zhang
- Division of Experimental Vascular Research, Institute of Clinical Science in Lund, Lund University, Lund, Sweden
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8
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Lee JS, Suh JM, Park HG, Bak EJ, Yoo YJ, Cha JH. Heparin-binding epidermal growth factor-like growth factor inhibits adipocyte differentiation at commitment and early induction stages. Differentiation 2007; 76:478-87. [PMID: 18093224 DOI: 10.1111/j.1432-0436.2007.00250.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Adipocytokines, bioactive molecules secreted from adipose tissues, play important roles in physiology, development, and disease. Recently, heparin-binding epidermal growth factor-like growth factor (HB-EGF) was identified as an adipocytokine whose expression correlates with obesity. However, the biological role of fat-secreted HB-EGF is still unclear. In this study, we investigated the effects of HB-EGF on the adipocyte differentiation of C3H10T1/2 pluripotent mesenchymal cells. Upon adipogenic conversion of C3H10T1/2 cells, HB-EGF displayed dynamic changes in expression where an initial decrease was followed by increased levels of expression at later stages. HB-EGF treatment during adipogenic induction inhibited lipid accumulation and decreased the expression of adipocyte molecular markers (fatty acid-binding protein, peroxisome proliferator-activated receptor gamma, and CAAT enhancer-binding protein alpha) and lipogenic genes (glucose transporter, fatty acid synthetase, and lipoprotein lipase). Therefore, HB-EGF has an inhibitory effect on adipocyte differentiation. Administration of HB-EGF at various intervals during adipocyte differentiation revealed that HB-EGF acts during the early stages of adipocyte differentiation, but not at the later stages of differentiation. Furthermore, HB-EGF was able to block the commitment of pluripotent mesenchymal cells to the adipocyte lineage triggered by bone morphogenic protein 4 treatment. These data suggest that HB-EGF acts as a negative regulator of adipogenesis by inhibiting the commitment and early differentiation of the adipose lineage. The inhibitory role of HB-EGF on adipocyte differentiation of pluripotent mesenchymal cells sheds light on potential mechanisms that control adipose tissue homeostasis.
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Affiliation(s)
- Jeong Soon Lee
- Department of Oral Biology, BK21 Project, Oral Science Research Center, Yonsei University College of Dentistry, Seoul 120-752, Korea
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Muto A, Fitzgerald TN, Pimiento JM, Maloney S, Teso D, Paszkowiak JJ, Westvik TS, Kudo FA, Nishibe T, Dardik A. Smooth muscle cell signal transduction: implications of vascular biology for vascular surgeons. J Vasc Surg 2007; 45 Suppl A:A15-24. [PMID: 17544020 PMCID: PMC1939976 DOI: 10.1016/j.jvs.2007.02.061] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Accepted: 02/17/2007] [Indexed: 12/31/2022]
Abstract
Vascular smooth muscle cells exhibit varied responses after vessel injury and surgical interventions, including phenotypic switching, migration, proliferation, protein synthesis, and apoptosis. Although the source of the smooth muscle cells that accumulate in the vascular wall is controversial, possibly reflecting migration from the adventitia, from the circulating blood, or in situ differentiation, the intracellular signal transduction pathways that control these processes are being defined. Some of these pathways include the Ras-mitogen-activated protein kinase, phosphatidylinositol 3-kinase-Akt, Rho, death receptor-caspase, and nitric oxide pathways. Signal transduction pathways provide amplification, redundancy, and control points within the cell and culminate in biologic responses. We review some of the signaling pathways activated within smooth muscle cells that contribute to smooth muscle cell heterogeneity and development of pathology such as restenosis and neointimal hyperplasia.
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MESH Headings
- Animals
- Apoptosis
- Bone Marrow Cells/metabolism
- Cell Differentiation
- Cell Movement
- Cell Proliferation
- Constriction, Pathologic/metabolism
- Constriction, Pathologic/pathology
- Extracellular Matrix/metabolism
- Humans
- Hyperplasia/metabolism
- Hyperplasia/pathology
- Muscle, Smooth, Vascular/injuries
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- Muscle, Smooth, Vascular/surgery
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Phenotype
- Protein Kinases/metabolism
- Signal Transduction
- Stem Cells/metabolism
- Vascular Surgical Procedures/adverse effects
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Affiliation(s)
- Akihito Muto
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Department of Interdepartmental Program in Vascular Biology and Transplantation, Yale University School of Medicine, New Haven, CT, USA
| | - Tamara N Fitzgerald
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Department of Interdepartmental Program in Vascular Biology and Transplantation, Yale University School of Medicine, New Haven, CT, USA
| | - Jose M Pimiento
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Department of Interdepartmental Program in Vascular Biology and Transplantation, Yale University School of Medicine, New Haven, CT, USA
- Saint Mary’s Hospital, Waterbury, CT, USA
| | - Stephen Maloney
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Department of Interdepartmental Program in Vascular Biology and Transplantation, Yale University School of Medicine, New Haven, CT, USA
- Saint Mary’s Hospital, Waterbury, CT, USA
| | - Desarom Teso
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Saint Mary’s Hospital, Waterbury, CT, USA
| | - Jacek J Paszkowiak
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Saint Mary’s Hospital, Waterbury, CT, USA
| | - Tormod S Westvik
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Department of Interdepartmental Program in Vascular Biology and Transplantation, Yale University School of Medicine, New Haven, CT, USA
| | - Fabio A Kudo
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Department of Interdepartmental Program in Vascular Biology and Transplantation, Yale University School of Medicine, New Haven, CT, USA
| | | | - Alan Dardik
- Department of Surgery, Yale University School of Medicine, New Haven, CT, USA
- Department of Interdepartmental Program in Vascular Biology and Transplantation, Yale University School of Medicine, New Haven, CT, USA
- VA Connecticut Healthcare System, West Haven, CT, USA
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10
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Dreux AC, Lamb DJ, Modjtahedi H, Ferns GAA. The epidermal growth factor receptors and their family of ligands: their putative role in atherogenesis. Atherosclerosis 2005; 186:38-53. [PMID: 16076471 DOI: 10.1016/j.atherosclerosis.2005.06.038] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 06/21/2005] [Accepted: 06/23/2005] [Indexed: 12/12/2022]
Abstract
The epidermal growth factor receptor is a member of type-I growth factor receptor family with tyrosine kinase activity that is activated following the binding of multiple cognate ligands. Several members of the EGF family of ligands are expressed by cells involved in atherogenesis. EGF receptor mediated processes have been well characterised within epithelial, smooth muscle and tumour cell lines in vitro, and the EGF receptor has been identified immunocytochemically on intimal smooth muscle cells within atherosclerotic plaques. There is also limited evidence for the expression of the EGF receptor family on leukocytes, although their function has yet to be clarified. In this review, we will discuss the biological functions of this receptor and its ligands and their potential to modulate the function of cells involved in the atherosclerotic process.
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Affiliation(s)
- Alys C Dreux
- Centre for Clinical Science & Measurement, School of Biomedical & Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
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Wong MWN, Tang YN, Fu SC, Lee KM, Chan KM. Triamcinolone suppresses human tenocyte cellular activity and collagen synthesis. Clin Orthop Relat Res 2004:277-81. [PMID: 15123960 DOI: 10.1097/01.blo.0000118184.83983.65] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glucocorticoid injection is widely used in tendon disorders. Despite previous studies on the histologic and biomechanical changes in tendons after glucocorticoid injections, the role of glucocorticoid in tendon rupture still is controversial. It was hypothesized that glucocorticoid has a direct deleterious effect on human tenocytes, suppressing its cellular activity and collagen production. Primary cultures of human tenocytes were obtained from explants of healthy patellar tendon harvested during anterior cruciate ligament reconstructions. The effects on cell viability and cell proliferation were measured by [3-(4,5-demethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and 5-bromo-deoxyuridine incorporations. The effect on collagen synthesis was measured by H-proline incorporation assay. Triamcinolone acetonide at 10 to 10 mol/L decreased human tenocyte viability to 45% to 88% of control in a dose-dependent manner. Cell proliferation was suppressed to 87% +/- 8% at all doses. Treatment with 1 micromol/L triamcinolone acetonide reduced the amount of collagen synthesis as measured by H-proline incorporation from 40 +/- 2 cpm/1000 cells to 27 +/- 4 cpm/1000 cells. The suppressed human tenocyte cellular activity and reduced collagen production may lead to disturbed tendon structure and predispose the tendon to subsequent spontaneous rupture.
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Affiliation(s)
- Margaret Wan Nar Wong
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
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12
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Koo BH, Kim DS. Factor Xa induces mitogenesis of vascular smooth muscle cells via autocrine production of epiregulin. J Biol Chem 2003; 278:52578-86. [PMID: 14570897 DOI: 10.1074/jbc.m310007200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Factor Xa has been reported to elicit smooth muscle cell proliferation via autocrine release of platelet-derived growth factor. However, this study has shown that factor Xa-induced mitogenesis of rat aortic smooth muscle cell is independent of platelet-derived growth factor. We also could not observe any platelet-derived growth factor isoforms in the cultured medium of factor Xa-stimulated cells. Our finding that the cultured medium of factor Xa-stimulated cells strongly induces rat aortic smooth muscle cell mitogenesis in the absence of factor Xa activity led us to explore the existence of a novel autocrine pathway. The autocrine growth factor was purified from the cultured medium and was identified to be epiregulin. Recombinant epiregulin was also able to induce the mitogenesis. The secretion of epiregulin from factor Xa-stimulated rat aortic smooth muscle cell required mRNA expression and protein synthesis of the growth factor. The mitogenic effect of factor Xa on rat aortic smooth muscle cell was significantly reduced by anti-epiregulin antibody or by antisense oligodeoxynucleotide to epiregulin. Several lines of experimental evidence clearly indicate that the autocrine production of epiregulin, an epidermal growth factor-related ligand, is induced in the factor Xa-stimulated mitogenic process of rat aortic smooth muscle cell.
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Affiliation(s)
- Bon-Hun Koo
- Department of Biochemistry, College of Science, Yonsei University, Seoul 120-749, Korea
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13
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Wong MWN, Tang YYN, Lee SKM, Fu BSC, Chan BP, Chan CKM. Effect of dexamethasone on cultured human tenocytes and its reversibility by platelet-derived growth factor. J Bone Joint Surg Am 2003; 85:1914-20. [PMID: 14563798 DOI: 10.2106/00004623-200310000-00008] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Many cases of tendon rupture after glucocorticoid injections have been reported in the literature. Despite previous studies on the histological and biomechanical changes in tendons after glucocorticoid injections, the role of glucocorticoid in causing tendon rupture still remains controversial. The objective of this study was to determine whether glucocorticoid has deleterious effects on the cellular metabolism and collagen production of cultured human tenocytes and the reversibility of these effects by platelet-derived growth factor-BB (PDGFBB). METHODS Primary cultures of human tenocytes obtained from explants of healthy patellar tendon, harvested during anterior cruciate ligament reconstructions, were performed. The effects on cell viability, cell proliferation, and induction of apoptosis were measured by [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, 5-bromo-deoxyuridine incorporation, and DNA fragmentation assay, respectively. The effect on collagen synthesis was measured by (3) H-proline incorporation assay. RESULTS The number of viable cells was decreased, in a dose-dependent manner, by the administration of 10 (-9) to 10 (-4) -M dexamethasone. This dose range also suppressed cell proliferation. No apoptotic effect was detected. Treatment with 10 (-6) -M dexamethasone significantly reduced the amount of collagen synthesis. Co-incubation with 10 ng/mL of PDGFBB significantly reversed the effects caused by 10 (-6) -M dexamethasone. CONCLUSIONS Dexamethasone significantly decreased cell viability, suppressed cell proliferation, and reduced collagen synthesis in cultured human tenocytes. The effects were reversed by the simultaneous administration of PDGFBB.
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Affiliation(s)
- Margaret Wan Nar Wong
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin.
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14
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Abstract
Vascular smooth muscle cells (VSMC) exhibit several growth responses to agonists that regulate their function including proliferation (hyperplasia with an increase in cell number), hypertrophy (an increase in cell size without change in DNA content), endoreduplication (an increase in DNA content and usually size), and apoptosis. Both autocrine growth mechanisms (in which the individual cell synthesizes and/or secretes a substance that stimulates that same cell type to undergo a growth response) and paracrine growth mechanisms (in which the individual cells responding to the growth factor synthesize and/or secrete a substance that stimulates neighboring cells of another cell type) are important in VSMC growth. In this review I discuss the autocrine and paracrine growth factors important for VSMC growth in culture and in vessels. Four mechanisms by which individual agonists signal are described: direct effects of agonists on their receptors, transactivation of tyrosine kinase-coupled receptors, generation of reactive oxygen species, and induction/secretion of other growth and survival factors. Additional growth effects mediated by changes in cell matrix are discussed. The temporal and spatial coordination of these events are shown to modulate the environment in which other growth factors initiate cell cycle events. Finally, the heterogeneous nature of VSMC developmental origin provides another level of complexity in VSMC growth mechanisms.
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Affiliation(s)
- B C Berk
- Center for Cardiovascular Research, University of Rochester, School of Medicine and Dentistry, Rochester, New York 14642, USA.
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15
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Robey RB, Raval BJ, Ma J, Santos AV. Thrombin is a novel regulator of hexokinase activity in mesangial cells. Kidney Int 2000; 57:2308-18. [PMID: 10844601 DOI: 10.1046/j.1523-1755.2000.00091.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Hexokinase (HK) activity is fundamentally important to cellular glucose uptake and metabolism. Phorbol esters increase both HK activity and glucose utilization in cultured mesangial cells via a protein kinase C (PKC)- and extracellular signal-regulated kinases 1 and 2 (ERK1/2)-dependent mechanism. In adult kidneys, increased HK activity has been reported in both glomerular injury and in diabetes, but the mechanisms responsible for these changes are unknown. Thrombin, a known activator of both PKC and ERK1/2, is increased in the settings of renal injury and diabetes. Thus, thrombin may contribute to the observed changes in HK activity in vivo. METHODS Thrombin and thrombin receptor agonists were tested for the ability to increase HK activity and glucose metabolism in murine mesangial (SV40 MES 13) cells. ERK1/2 activation was also evaluated in parallel. Thrombin inhibition (hirudins), PKC depletion, Ser-Thr kinase inhibition (H-7), MEK1/2 inhibition (PD98059), pertussis toxin (PTX), and general inhibitors of transcription or translation were then tested for the ability to attenuate these effects. RESULTS Thrombin (>/=0.01 U/mL) mimicked the effect of phorbol esters, increasing HK activity> 50% within 12 to 24 hours (P < 0.05). This effect was inhibited by hirudins, mimicked by thrombin receptor agonists, and accompanied by increased Glc utilization. H-7, PD98059, and general inhibitors of transcription or translation-but not PTX-prevented thrombin-induced HK activity at 24 hours. PKC depletion and PD98059 also blocked the associated phosphorylation and activation of ERK1/2. CONCLUSIONS Thrombin increases mesangial cell HK activity via a PTX-insensitive mechanism involving thrombin receptor activation, PKC-dependent activation of ERK1/2, and both ongoing gene transcription and de novo protein synthesis. As such, thrombin is a novel regulator of HK activity in mesangial cells and may play a role in coupling renal injury to metabolism.
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Affiliation(s)
- R B Robey
- Department of Medicine, Section of Nephrology, University of Illinois at Chicago College of Medicine and VA Chicago Health Care System, West Side Division, Chicago, Illinois 60612-7315, USA.
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16
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Abstract
Platelet-derived growth factor (PDGF) is a major mitogen for connective tissue cells and certain other cell types. It is a dimeric molecule consisting of disulfide-bonded, structurally similar A- and B-polypeptide chains, which combine to homo- and heterodimers. The PDGF isoforms exert their cellular effects by binding to and activating two structurally related protein tyrosine kinase receptors, denoted the alpha-receptor and the beta-receptor. Activation of PDGF receptors leads to stimulation of cell growth, but also to changes in cell shape and motility; PDGF induces reorganization of the actin filament system and stimulates chemotaxis, i.e., a directed cell movement toward a gradient of PDGF. In vivo, PDGF has important roles during the embryonic development as well as during wound healing. Moreover, overactivity of PDGF has been implicated in several pathological conditions. The sis oncogene of simian sarcoma virus (SSV) is related to the B-chain of PDGF, and SSV transformation involves autocrine stimulation by a PDGF-like molecule. Similarly, overproduction of PDGF may be involved in autocrine and paracrine growth stimulation of human tumors. Overactivity of PDGF has, in addition, been implicated in nonmalignant conditions characterized by an increased cell proliferation, such as atherosclerosis and fibrotic conditions. This review discusses structural and functional properties of PDGF and PDGF receptors, the mechanism whereby PDGF exerts its cellular effects, and the role of PDGF in normal and diseased tissues.
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Affiliation(s)
- C H Heldin
- Ludwig Institute for Cancer Research, Biomedical Center, and Department of Pathology, University Hospital, Uppsala, Sweden.
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17
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Poon M, Liu B, Taubman MB. Identification of a novel dexamethasone-sensitive RNA-destabilizing region on rat monocyte chemoattractant protein 1 mRNA. Mol Cell Biol 1999; 19:6471-8. [PMID: 10490587 PMCID: PMC84617 DOI: 10.1128/mcb.19.10.6471] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/1999] [Accepted: 07/09/1999] [Indexed: 11/20/2022] Open
Abstract
Glucocorticoids are potent anti-inflammatory agents widely used in the treatment of human disease. We have previously shown that the inflammatory cytokine monocyte chemoattractant protein 1 (MCP-1) is regulated posttranscriptionally by glucocorticoids in arterial smooth muscle cells (SMC). To elucidate the mechanism mediating this effect, in vitro-transcribed radiolabeled MCP-1 mRNA was incubated with cytoplasmic extracts from SMC and analyzed by gel electrophoresis. Extracts from SMC treated with platelet-derived growth factor (PDGF) did not degrade the transcripts for up to 3 h. In contrast, extracts from cells treated with 1 microM dexamethasone (Dex) alone or in combination with PDGF degraded the probe with a half-life of approximately 15 min. Dex had maximal effect at concentrations above 0.01 microM and was effective on both rat and human MCP-1 transcripts. By deletion analysis, the Dex-sensitive region of the MCP-1 mRNA was localized to the initial 224 nucleotides (nt) at the 5' end and did not involve an AU-rich sequence in the 3' untranslated end. The 224-nt region conferred Dex sensitivity to heterologous mRNA. These studies provide new insights into the molecular mechanisms underlying the effect of glucocorticoids on gene expression.
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Affiliation(s)
- M Poon
- The Zena and Michael A. Wiener Cardiovascular Institute and Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA.
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18
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Dixon ER, Weinberg JA, Lew DB. Effect of dexamethasone on bovine airway smooth muscle cell proliferation. J Asthma 1999; 36:519-25. [PMID: 10498047 DOI: 10.3109/02770909909054558] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Airway smooth muscle proliferation is a key component of airway wall remodelling that occurs as a consequence of inflammation in asthma. Studies were conducted to examine the effect of dexamethasone on airway smooth muscle cell (ASMC) proliferation in vitro. Dexamethasone (25-250 nM) significantly inhibited DNA synthesis and cell division induced by beta-hexosaminidase A (Hex A, 50 nM) in bovine ASMC. The inhibitory effect of dexamethasone on DNA synthesis was variable depending on the growth factors: significant effect was observed on Hex A and insulin; no significant effect was observed on epidermal growth factor and fetal bovine serum.
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Affiliation(s)
- E R Dixon
- The Crippled Children's Foundation Research Center at LeBonheur Children's Medical Center, Memphis, Tennessee, USA
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19
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Mori K, Shioi A, Jono S, Nishizawa Y, Morii H. Dexamethasone enhances In vitro vascular calcification by promoting osteoblastic differentiation of vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 1999; 19:2112-8. [PMID: 10479652 DOI: 10.1161/01.atv.19.9.2112] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular calcification is often associated with atherosclerotic lesions. Moreover, the process of atherosclerotic calcification has several features similar to the mineralization of skeletal tissue. Therefore, we hypothesized that vascular smooth muscle cells might acquire osteoblastic characteristics during the development of atherosclerotic lesions. In the present study, we investigated the effect of dexamethasone (Dex), which is well known to be a potent stimulator of osteoblastic differentiation in vitro, on vascular calcification by using an in vitro calcification model. We demonstrated that Dex increased bovine vascular smooth muscle cell (BVSMC) calcification in a dose- and time-dependent manner. Dex also enhanced several phenotypic markers of osteoblasts, such as alkaline phosphatase activity, procollagen type I carboxy-terminal peptide production, and cAMP responses to parathyroid hormone in BVSMCs. We also examined the effects of Dex on human osteoblast-like (Saos-2) cells and compared its effects on BVSMCs and Saos-2 cells. The effects of Dex on alkaline phosphatase activity and the cAMP response to parathyroid hormone in BVSMCs were less prominent than those in Saos-2 cells. Interestingly, we detected that Osf2/Cbfa1, a key transcription factor in osteoblastic differentiation, was expressed in both BVSMCs and Saos-2 cells and that Dex increased the gene expression of both transcription factors. These findings suggest that Dex may enhance osteoblastic differentiation of BVSMCs in vitro.
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Affiliation(s)
- K Mori
- Second Department of Internal Medicine, Osaka City University Medical School, Osaka, Japan
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20
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Sakai M, Biwa T, Matsumura T, Takemura T, Matsuda H, Anami Y, Sasahara T, Kobori S, Shichiri M. Glucocorticoid inhibits oxidized LDL-induced macrophage growth by suppressing the expression of granulocyte/macrophage colony-stimulating factor. Arterioscler Thromb Vasc Biol 1999; 19:1726-33. [PMID: 10397691 DOI: 10.1161/01.atv.19.7.1726] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Glucocorticoid, an anti-inflammatory agent, inhibits the development of atherosclerosis in various experimental animal models. This is partially explained by its ability to inhibit smooth muscle cell migration and proliferation in the intima and to reduce chemotaxis of circulating monocytes and leukocytes into the subendothelial spaces. We have recently demonstrated that oxidized LDL (Ox-LDL) has a mitogenic activity for macrophages in vitro in which Ox-LDL-induced granulocyte/macrophage colony-stimulating factor (GM-CSF) production plays an important role. Proliferation of cellular components is one of the characteristic events in the development and progression of atherosclerotic lesions. In the present study, we investigated the effects of glucocorticoids on Ox-LDL-induced macrophage growth. Dexamethasone, prednisolone, and cortisol inhibited Ox-LDL-induced thymidine incorporation into macrophages by 85%, 70%, and 50%, respectively. Ox-LDL induced a significant production of GM-CSF by macrophages, which was effectively inhibited by dexamethasone, prednisolone, and cortisol by 80%, 65%, and 50%, respectively. Dexamethasone-mediated inhibition of Ox-LDL-induced GM-CSF mRNA expression and macrophage growth was significantly abrogated by RU-486, a glucocorticoid receptor antagonist. Our results suggest that the inhibitory effects of glucocorticoids on macrophage growth may be due to the inhibition of Ox-LDL-induced GM-CSF production through transactivation of the glucocorticoid receptor.
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Affiliation(s)
- M Sakai
- Department of Metabolic Medicine, Kumamoto University School of Medicine, Division of Cardiology, Kumamoto National Hospital, Kumamoto, Japan
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21
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Kayanoki Y, Higashiyama S, Suzuki K, Asahi M, Kawata S, Matsuzawa Y, Taniguchi N. The requirement of both intracellular reactive oxygen species and intracellular calcium elevation for the induction of heparin-binding EGF-like growth factor in vascular endothelial cells and smooth muscle cells. Biochem Biophys Res Commun 1999; 259:50-5. [PMID: 10334914 DOI: 10.1006/bbrc.1999.0723] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heparin-binding EGF-like growth factor (HB-EGF), which is a potent mitogen for vascular smooth muscle cells (SMC) and fibroblasts, has been reported to be strongly implicated in atherosclerosis and wound healing. HB-EGF mRNA is known to be induced by thrombin, angiotensin-II, basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), and HB-EGF itself in SMC. In vascular endothelial cells (EC), its mRNA is induced by tumor necrosis factor-alpha and interleukin-1beta. Only phorbol 12-myristate 13-acetate is a common inducer for HB-EGF mRNA. The present study shows that calcium ionophore A23187 also induced HB-EGF mRNA in both SMC and in EC and that both intracellular reactive oxygen species (ROS) and an increase in calcium levels were essential for the induction of this growth factor mRNA. While HB-EGF caused an increase in both intracellular ROS and calcium in SMC, it increased only calcium, but not the intracellular ROS in EC. When the intracellular ROS was elevated by treatment with hydrogen peroxide (H2O2) or by depletion of glutathione by buthionine sulfoxamine, both HB-EGF and thrombin were observed to upregulate HB-EGF mRNA in EC. These data suggest that H2O2, produced by activated leukocytes in inflammatory lesions, upregulates HB-EGF mRNA by cooperating with thrombin, angiotensin-II, and the above growth factors. Since activated macrophages under the EC are thought to elevate the ROS in neighboring EC, this mechanism might play a major role in the progression of atherosclerosis and for wound healing.
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Affiliation(s)
- Y Kayanoki
- Department of Biochemistry, Second Department of Internal Medicine, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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22
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Cucina A, Borrelli V, Di Carlo A, Pagliei S, Corvino V, Santoro-D'Angelo L, Cavallaro A, Sterpetti AV. Thrombin induces production of growth factors from aortic smooth muscle cells. J Surg Res 1999; 82:61-6. [PMID: 10068527 DOI: 10.1006/jsre.1998.5514] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Myointimal hyperplasia is a common complication of arterial recontructive surgery. The serine protease thrombin has a major role in vessel wall healing and eventual myointimal hyperplasia formation. The aim of this study was to determine the effect of thrombin on the production of PDGF AA and bFGF by arterial smooth muscle cells. MATERIALS AND METHODS Bovine smooth muscle cells were stimulated with thrombin in a serum-free culture. The release of PDGF AA and bFGF was assessed by ELISA. The effect of thrombin on the proliferation of confluent monolayers of bovine smooth muscle cells was determined by tritiated thymidine uptake. RESULTS Smooth muscle cells stimulated with thrombin released more PDGF AA (P < 0.001) and bFGF (P < 0.001) than the control. Addition of anti-PDGF AA and anti-bFGF antibodies to the medium of smooth muscle cell cultures neutralized the mitogenic effect of thrombin (P < 0.001). CONCLUSIONS The findings of our study suggest that thrombin may lead to myointimal hyperplasia formation through induction of PDGF and bFGF production by smooth muscle cells.
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MESH Headings
- Animals
- Antibodies, Monoclonal
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Arteries/injuries
- Arteries/pathology
- Arteries/surgery
- Cattle
- Cell Division/drug effects
- Cells, Cultured
- Culture Media, Conditioned
- DNA/biosynthesis
- Fibroblast Growth Factor 2/biosynthesis
- Fibroblast Growth Factor 2/immunology
- Humans
- Hyperplasia
- Kinetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Platelet-Derived Growth Factor/biosynthesis
- Platelet-Derived Growth Factor/immunology
- Thrombin/pharmacology
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Affiliation(s)
- A Cucina
- Dipartimento di Istologia & Embriologia Medica, University of Rome, La Sapienza, Italy
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23
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Park JM, Borer JG, Freeman MR, Peters CA. Stretch activates heparin-binding EGF-like growth factor expression in bladder smooth muscle cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:C1247-54. [PMID: 9814973 DOI: 10.1152/ajpcell.1998.275.5.c1247] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cultured rat bladder smooth muscle cells (SMC) were grown on collagen-coated silicone membranes and subjected to continuous cycles of stretch-relaxation. Semiquantitative RT-PCR analysis revealed a time-dependent increase in heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) mRNA levels after stretch, with maximal levels appearing after 4 h. Immunostaining for proHB-EGF revealed higher levels of HB-EGF protein in the stretched than in the nonstretched SMC. The ANG II receptor type 1 antagonist losartan markedly suppressed stretch-activated HB-EGF expression. ANG II levels were 3.3-fold higher in the stretch- than in the non-stretch-conditioned media. Stretch stimulation of bladder SMC that had been transiently transfected with an HB-EGF promoter-luciferase expression construct resulted in an 11-fold increase in reporter activity. Mechanical stretch induced a 4.7-fold increase in tritiated thymidine incorporation rate, and this was reduced by 25% in the presence of losartan. We conclude that mechanical stretch activates HB-EGF gene expression in bladder SMC and that this is mediated in part by autocrine ANG II secretion.
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Affiliation(s)
- J M Park
- Urologic Laboratory, Department of Urology, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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24
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Kawai Y, Hayashi T, Eguchi K, Asazuma K, Masamura K, Iwamuro A, Takano Y, Tada H, Matsukawa S, Miyamori I. Effects of brief glucocorticoid exposure on growth of vascular smooth muscle cells in culture. Biochem Biophys Res Commun 1998; 245:493-6. [PMID: 9571182 DOI: 10.1006/bbrc.1998.8462] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
While prolonged exposure of vascular smooth muscle cells (VSMC) to glucocorticoid has been shown to inhibit cell proliferation, the effect of a brief pulse exposure is not known. We studied the short-term effects of pulse exposure to dexamethasone (DEX) on DNA synthesis in cultured VSMC. VSMC were pulsed with DEx for varying time intervals and [3H]thymidine incorporation into cells after 24 h was measured. Exposure to DEX for 24 h decreased [3H]thymidine incorporation, while pulse treatments with DEX from 2 min to 6 h significantly increased [3H]thymidine incorporation. Maximal proliferative effect was observed with a 20-min exposure. The effect of a 20-min pulse was dose-dependent, with the half-maximal dose of DEX being approximately 10(-7) M. A selective glucocorticoid receptor antagonist, RU486, inhibited the proliferative effect of DEx. Concentrated conditioned medium from cells exposed to 10(-6) M DEX increased [3H]thymidine incorporation by other VSMC in a dose-dependent manner. These results suggest that short-term pulse DEX exposure is capable of producing one or more autocrine growth factors in VSMC via a glucocorticoid receptor action. This effect of glucocorticoid pulses may contribute to the pathogenesis of arteriosclerosis and hypertension.
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Affiliation(s)
- Y Kawai
- Third Department of Internal Medicine, Fukui Medical University, Matsuokacho, Japan.
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25
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Warshamana GS, Martinez S, Lasky JA, Corti M, Brody AR. Dexamethasone activates expression of the PDGF-alpha receptor and induces lung fibroblast proliferation. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:L499-507. [PMID: 9575867 DOI: 10.1152/ajplung.1998.274.4.l499] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Corticosteroids (CSs) are commonly used for anti-inflammatory therapy in asthma and in interstitial lung diseases. In attempting to understand the mechanisms through which CSs control cell proliferation, we have carried out experiments to test the effects of dexamethasone (Dex) on the growth of lung fibroblasts. Using mouse 3T3 fibroblasts as well as early-passage rat lung fibroblasts (RLFs), we show that the quiescent cells in 1% serum or in serum-free media proliferate significantly in response to the addition of 10(-7) to 10(-9) M Dex. Increases as high as fourfold in cell numbers were recorded for the RLFs after 48 h in culture. A polyclonal antibody to the AB isoform of human platelet-derived growth factor (PDGF) blocked the proliferative response. As expected, the fibroblasts produced primarily PDGF-A chain, and the RLFs exhibited few PDGF-alpha receptors (PDGF-R alpha), the receptor type necessary for binding the AA isoform. Accordingly, we determined that Dex upregulated PDGF-R alpha mRNA and protein. Therefore, we can postulate that Dex-induced fibroblast proliferation is mediated, at least in part, by PDGF-AA, which binds to the PDGF-R alpha.
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Affiliation(s)
- G S Warshamana
- Lung Biology Program, Tulane University Medical Center, New Orleans, Louisiana 70112, USA
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26
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Abstract
HB-EGF is a heparin-binding member of the EGF family that was initially identified in the conditioned medium of human macrophages. Soluble mature HB-EGF is proteolytically processed from a larger membrane-anchored precursor and is a potent mitogen and chemotactic factor for fibroblasts, smooth muscle cells but not endothelial cells. HB-EGF activates two EGF receptor subtypes, HER1 and HER4 and binds to cell surface HSPG. The transmembrane form of HB-EGF is a juxtacrine growth and adhesion factor and is uniquely the receptor for diphtheria toxin. HB-EGF gene expression is highly regulated, for example by cytokines, growth factors, and transcription factors such as MyoD. HB-EGF has been implicated as a participant in a variety of normal physiological processes such as blastocyst implantation and wound healing, and in pathological processes such as tumor growth, SMC hyperplasia and atherosclerosis.
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Affiliation(s)
- G Raab
- Department of Surgery, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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27
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Höper MM, Voelkel NF, Bates TO, Allard JD, Horan M, Shepherd D, Tuder RM. Prostaglandins induce vascular endothelial growth factor in a human monocytic cell line and rat lungs via cAMP. Am J Respir Cell Mol Biol 1997; 17:748-56. [PMID: 9409562 DOI: 10.1165/ajrcmb.17.6.2888] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Prostaglandins have emerged as a therapeutic option for patients with peripheral vascular disease as well as pulmonary hypertension as a means to increase blood flow. We tested the hypothesis that prostaglandins regulate vascular endothelial growth factor (VEGF) expression in the human monocytic THP-1 cell line and in isolated perfused rat lungs. Our data show that the stable PGI2-analogue iloprost induces VEGF gene expression (predominantly VEGF121, but also VEGF165 isoforms) and VEGF protein synthesis in THP-1 cells. This effect is abolished by dexamethasone and by Rp-cAMP, a specific inhibitor of cAMP-dependent protein kinase (PKA) activation. The calcium channel blocker diltiazem has no effect on the iloprost-induced VEGF gene expression, and depletion of intracellular Ca2+ stores by long-term exposure (16 h) of THP-1 cells to thapsigargin does not inhibit iloprost-induced VEGF gene expression, suggesting that an increase in intracellular Ca2+ is not essential for VEGF gene induction by iloprost. However, an increase of intracellular Ca2+ by a short-term (2 h) exposure of THP-1 cells to thapsigargin or to the calcium-ionophore A23187 increases VEGF mRNA levels, indicating that a change in intracellular Ca2+ by itself can alter VEGF gene expression. The effects of thapsigargin or A23187 on VEGF gene expression are also mediated via cAMP-PKA since they are inhibited by Rp-cAMP. In isolated perfused rat lungs, PGI2 and PGE2 increases VEGF mRNA abundance whereas Rp-cAMP inhibits the prostaglandin-induced VEGF gene activation. Thus, our data suggest that prostaglandins stimulate VEGF gene expression in monocytic cells and in rat lungs via a cAMP-dependent mechanism.
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Affiliation(s)
- M M Höper
- Department of Pathology, Pulmonary Hypertension Center, and University of Colorado Health Sciences Center, Denver 80262, USA
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28
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Che W, Asahi M, Takahashi M, Kaneto H, Okado A, Higashiyama S, Taniguchi N. Selective induction of heparin-binding epidermal growth factor-like growth factor by methylglyoxal and 3-deoxyglucosone in rat aortic smooth muscle cells. The involvement of reactive oxygen species formation and a possible implication for atherogenesis in diabetes. J Biol Chem 1997; 272:18453-9. [PMID: 9218489 DOI: 10.1074/jbc.272.29.18453] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Methylglyoxal (MG) and 3-deoxyglucosone (3-DG), reactive dicarbonyl metabolites in the glyoxalase system and glycation reaction, respectively, selectively induced heparin-binding epidermal growth factor (HB-EGF)-like growth factor mRNA in a dose- and time-dependent manner in rat aortic smooth muscle cells (RASMC). A nuclear run-on assay revealed that the dicarbonyl may regulate expression of HB-EGF at the transcription level. The dicarbonyl also increased the secretion of HB-EGF from RASMC. However, platelet-derived growth factor, another known growth factor of smooth muscle cells (SMC), was not induced by both dicarbonyls. The dicarbonyl augmented intracellular peroxides prior to the induction of HB-EGF mRNA as judged by flow cytometric analysis using 2',7'-dichlorofluorescin diacetate. N-Acetyl-L-cysteine and aminoguanidine suppressed both dicarbonyl-increased HB-EGF mRNA and intracellular peroxide levels in RASMC. DL-Buthionine-(S, R)-sulfoximine increased the levels of 3-DG-induced HB-EGF mRNA. Furthermore, hydrogen peroxide alone also induced HB-EGF mRNA in RASMC. These results indicate that MG and 3-DG induce HB-EGF by increasing the intracellular peroxide levels. In addition, the pretreatment with 12-O-tetra-decanoylphorbol-13-acetate failed to alter dicarbonyl-induced HB-EGF mRNA expression in RASMC, suggesting that the signal transducing mechanism is not mediated by protein kinase C. Since HB-EGF is known as a potent mitogen for smooth muscle cells and is abundant in atherosclerotic plaques, the induction of HB-EGF by MG and 3-DG, as well as the concomitant increment of intracellular peroxides, may trigger atherogenesis during diabetes.
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MESH Headings
- Acetylcysteine/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Arteriosclerosis
- Cell Nucleus/metabolism
- Cells, Cultured
- Cycloheximide/pharmacology
- Dactinomycin/pharmacology
- Deoxyglucose/analogs & derivatives
- Deoxyglucose/pharmacology
- Diabetic Angiopathies
- Epidermal Growth Factor/biosynthesis
- Gene Expression/drug effects
- Guanidines/pharmacology
- Heparin/metabolism
- Heparin-binding EGF-like Growth Factor
- Intercellular Signaling Peptides and Proteins
- Kinetics
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Peroxides/metabolism
- Pyruvaldehyde/pharmacology
- RNA, Messenger/biosynthesis
- Rats
- Rats, Wistar
- Reactive Oxygen Species/metabolism
- Transcription, Genetic/drug effects
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Affiliation(s)
- W Che
- Department of Biochemistry, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565, Japan
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29
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Nishi E, Kume N, Ochi H, Moriwaki H, Wakatsuki Y, Higashiyama S, Taniguchi N, Kita T. Lysophosphatidylcholine increases expression of heparin-binding epidermal growth factor-like growth factor in human T lymphocytes. Circ Res 1997; 80:638-44. [PMID: 9130444 DOI: 10.1161/01.res.80.5.638] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Atherosclerotic lesions contain substantial numbers of activated T lymphocytes in addition to monocytes/macrophages. T cell-derived cytokines and growth factors may play a role in atherogenesis; however, stimuli responsible for T-cell activation in atherogenesis have not been fully elucidated. In this study, we provide evidence that lysophosphatidylcholine (lyso-PC), a polar phospholipid component increased in atherogenic lipoproteins and atherosclerotic lesions, can upregulate gene expression and secretion of heparin-binding epidermal growth factor-like growth factor (HB-EGF) in cultured T lymphocytes isolated from human peripheral blood. Effects of lyso-PC on T lymphocytes appear to be selective and specific, since lyso-PC also increases interleukin (IL)-2 receptor expression but does not affect mRNA levels for IL-2 or IL-4. Lyso-PC-induced upregulation of HB-EGF and IL-2 receptor mRNA in peripheral T cells is mostly dependent on exogenous IL-2 in conditioned medium. The effect of lyso-PC on HB-EGF induction was more potent in CD4+ cells than in CD8+ cells, although lyso-PC increases IL-2 receptor expression dramatically in both CD4+ cells and CD8+ cells. Lyso-PC similarly increased HB-EGF expression in Jurkat cells, a cell line for human CD4+ T lymphocytes. These results in vitro suggest that lyso-PC may be an important stimulus for T cells in atherogenesis in vivo to upregulate HB-EGF and that T cell-derived smooth muscle growth factors may modulate atherosclerotic progression.
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Affiliation(s)
- E Nishi
- Department of Geriatric Medicine, Graduate School of Medicine, Kyoto University, Sakyo-ku, Japan
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30
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Yoneyama A, Kamiya Y, Kawaguchi M, Fujinami T. Effects of dehydroepiandrosterone on proliferation of human aortic smooth muscle cells. Life Sci 1997; 60:833-8. [PMID: 9076322 DOI: 10.1016/s0024-3205(97)00011-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) have been shown to be associated with the progression of coronary atherosclerosis in clinical and in vivo studies. However, the mechanisms responsible for the association have not been determined. In the present study, we found that DHEA influences the in vitro growth of vascular smooth muscle cells obtained from the human aorta (hASMC). The concentrations of DHEA ranging from 10(-8) M to 10(-6) M significantly stimulated the mitogenesis of hASMC in serum-free culture. On the other hand, 4 hrs of pretreatment with DHEA attenuated the fetal calf serum induced proliferative effect in a dose-dependent manner. However, the in vitro effects of DHEA on the mitogenesis observed in hASMC were not seen in rat-derived aortic smooth muscle cell lines (A10 cells). With respect to DHEAS, the hormone, at concentrations up to 10(-5) M did not affect the growth of either hASMC or A10 cells in vitro. The growth response of hASMC to DHEA in vitro was markedly affected by the culture conditions. The differential proliferative effects of DHEA on smooth muscle cells between rat and human are of interest. We conclude that the effects of DHEA on mitogenesis of hASMC may, at least in part, explain the association between DHEA and atherosclerosis.
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Affiliation(s)
- A Yoneyama
- Third Department of Internal Medicine, Nagoya City University Medical School, Japan
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31
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Igura T, Kawata S, Miyagawa J, Inui Y, Tamura S, Fukuda K, Isozaki K, Yamamori K, Taniguchi N, Higashiyama S, Matsuzawa Y. Expression of heparin-binding epidermal growth factor-like growth factor in neointimal cells induced by balloon injury in rat carotid arteries. Arterioscler Thromb Vasc Biol 1996; 16:1524-31. [PMID: 8977458 DOI: 10.1161/01.atv.16.12.1524] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Balloon catheter injury of rat carotid arteries induces migration and proliferation of smooth muscle cells (SMCs), with subsequent neointimal formation. Several growth factors, such as platelet-derived growth factor and basic fibroblast growth factor, have been shown to be involved in this process, but the mechanisms that modulate the growth and/or migratory properties of SMCs remain unclear. In this study, we investigated whether heparin-binding epidermal growth factor-like growth factor (HB-EGF), which is known to be a potent SMC stimulator from in vitro study, is associated with the proliferative response of SMCs to arterial injury. Northern blot analysis showed that the transcript levels of HB-EGF increased rapidly approximately 12-fold within 2 hours after injury and declined by 2 days but remained 3-fold at 14 days. In situ hybridization analysis demonstrated that the transcript of HB-EGF remained strongly expressed in the neointima, especially near the luminal surface, at 14 days after injury. Immunohistochemical staining showed that HB-EGF protein was positive in the endothelium and only faintly visible in medial SMCs in uninjured vessels. In contrast, 2 days after injury, positive HB-EGF immunostaining was detected in the medial SMCs along the luminal surface. At 7 days, the neointimal SMCs exhibited strong immunostaining for HB-EGF, and at 14 days, they exhibited a gradient of HB-EGF expression with strong immunoreactivity in the most luminal cells. SMCs labeled with 5-bromo-2'-deoxyuridine in their nuclei showed strong immunostaining for HB-EGF protein. Furthermore, the epidermal growth factor receptor to which HB-EGF can bind was also immunostained positively in neointimal SMCs. These data suggest that HB-EGF may play an important role of the proliferation and migration of SMCs in the process of neointimal accumulation induced by arterial injury, probably in an autocrine, paracrine, and/or juxtacrine manner.
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Affiliation(s)
- T Igura
- Second Department of Internal Medicine, Osaka University Medical School, Japan.
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32
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Hughes AD, Clunn GF, Refson J, Demoliou-Mason C. Platelet-derived growth factor (PDGF): actions and mechanisms in vascular smooth muscle. GENERAL PHARMACOLOGY 1996; 27:1079-89. [PMID: 8981052 DOI: 10.1016/s0306-3623(96)00060-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
1. PDGF is a highly hydrophilic cationic glycoprotein (M(r) 28-35kDa) produced by platelets, monocyte/macrophages, endothelial cells and vascular smooth muscle cells under some conditions. 2. Since its original description, PDGF has attracted much attention and it is currently believed to play a role in atherosclerosis and other vascular pathologies. 3. This review describes the vascular biology of PDGF. It particularly focuses on recent findings regarding the intracellular signals activated by PDGF in the context of vascular smooth muscle cell proliferation, migration and, contraction.
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Affiliation(s)
- A D Hughes
- Department of Clinical Pharmacology, St. Mary's Hospital Medical School, Imperial College of Science Technology and Medicine, London, UK.
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33
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Peifley KA, Alberts GF, Hsu DK, Feng SL, Winkles JA. Heparin-binding epidermal growth factor-like growth factor regulates fibroblast growth factor-2 expression in aortic smooth muscle cells. Circ Res 1996; 79:263-70. [PMID: 8756003 DOI: 10.1161/01.res.79.2.263] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a vascular smooth muscle cell (SMC) mitogen and chemotactic factor that is expressed by endothelial cells, SMCs, monocytes/macrophages, and T lymphocytes. Both the membrane-anchored HB-EGF precursor and the secreted mature HB-EGF protein are biologically active; thus, HB-EGF may stimulate SMC growth via autocrine, paracrine, and juxtacrine mechanisms. In the present study, we report that HB-EGF treatment of serum-starved at aortic SMCs can induce fibroblast growth factor (FGF)-2 (basic FGF) gene expression but not FGF-1 (acidic FGF) gene expression. Increased FGF-2 mRNA expression is first detectable at 1 hour after HB-EGF addition, and maximal FGF-2 mRNA levels, corresponding to an approximately 46-fold level of induction, are present at 4 hours. The effect of HB-EGF on FGF-2 mRNA levels appears to be mediated primarily by a transcriptional mechanism and requires de novo synthesized proteins. HB-EGF induction of FGF-2 mRNA levels can be inhibited by treating cells with the anti-inflammatory glucocorticoid dexamethasone or the glycosaminoglycan heparin. Finally, Western blot analyses indicate that HB-EGF-treated SMCs also produce an increased amount of FGF-2 protein. These results indicate that HB-EGF expressed at sites of vascular injury or inflammation in vivo may upregulate FGF-2 production by SMCs.
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MESH Headings
- Animals
- Aorta/cytology
- Aorta/metabolism
- Blotting, Northern
- Blotting, Western
- Cells, Cultured
- Cycloheximide/pharmacology
- Dactinomycin/pharmacology
- Dexamethasone/pharmacology
- Epidermal Growth Factor/pharmacology
- Fibroblast Growth Factor 2/genetics
- Fibroblast Growth Factor 2/metabolism
- Heparin/pharmacology
- Heparin-binding EGF-like Growth Factor
- Intercellular Signaling Peptides and Proteins
- Kinetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Osmolar Concentration
- Protein Synthesis Inhibitors/pharmacology
- RNA, Messenger/metabolism
- Rats
- Rats, Inbred WKY
- Transcription, Genetic/drug effects
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Affiliation(s)
- K A Peifley
- Department of Molecular Biology, Holland Laboratory, American Red Cross, Rockville, Md 20855, USA
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34
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Nakano T, Kawamoto K, Higashino K, Arita H. Prevention of growth arrest-induced cell death of vascular smooth muscle cells by a product of growth arrest-specific gene, gas6. FEBS Lett 1996; 387:78-80. [PMID: 8654572 DOI: 10.1016/0014-5793(96)00395-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have purified Gas6 as a growth-potentiating factor for vascular smooth muscle cells (VSMCs) [Nakano, T. et al. (1995) J. Biol. Chem. 270, 5702-5705]. However, specific production of Gas6 in growth-arrested cells raises an intriguing question as to the physiological function of Gas6. In this study, we found that serum-starved VSMCs secreted some survival factors and depletion of the factors induced cell death of VSMCs. Finally, we demonstrated that cell death was prevented by the addition of Gas6, suggesting that one of the major biological activities of Gas6 is protection of growth-arrested VSMCs from death.
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Affiliation(s)
- T Nakano
- Discovery Research Laboratories II, Shionogi & Co., Ltd., Osaka, Japan
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35
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Billett MA, Adbeish IS, Alrokayan SA, Bennett AJ, Marenah CB, White DA. Increased expression of genes for platelet-derived growth factor in circulating mononuclear cells of hypercholesterolemic patients. Arterioscler Thromb Vasc Biol 1996; 16:399-406. [PMID: 8630666 DOI: 10.1161/01.atv.16.3.399] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Platelet-derived growth factor (PDGF) is implicated in the accumulation of smooth muscle cells in atherosclerotic lesions following monocyte migration through the vascular endothelium. We show here a 15- to 20-fold increase in expression of PDGF-A and -B genes (as measured by a quantitative reverse transcription-polymerase chain reaction assay of mRNA concentration) in circulating monocytes of hypercholesterolemic and hyperlipidemic patients compared with normocholesterolemic individuals. Strong positive correlations between PDGF-A and -B mRNA concentrations indicate that the two genes are coordinately regulated in mononuclear cells in both normal and hypercholesterolemic individuals. PDGF gene expression in patients correlates with concentrations of plasma total cholesterol and low-density lipoprotein cholesterol, a proven risk factor for atherosclerosis. Activation of monocyte PDGF expression may be an important component of the atherosclerotic risk associated with raised cholesterol levels and may represent an essential step in the early stages of atherogenesis. However, the marked increases in PDGF mRNA levels in patients with modest hypercholesterolemia compared with normal subjects suggest that other factors are involved. The relationship of monocyte PDGF expression to other atherosclerotic risk factors and to the different stages of atherosclerosis needs to be carefully evaluated.
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Affiliation(s)
- M A Billett
- Department of Biochemistry, University of Nottingham Medical School, Queen's Medical Centre, UK
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36
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Thyberg J. Differentiated properties and proliferation of arterial smooth muscle cells in culture. INTERNATIONAL REVIEW OF CYTOLOGY 1996; 169:183-265. [PMID: 8843655 DOI: 10.1016/s0074-7696(08)61987-7] [Citation(s) in RCA: 190] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The smooth muscle cell is the sole cell type normally found in the media of mammalian arteries. In the adult, it is a terminally differentiated cell that expresses cytoskeletal marker proteins like smooth muscle alpha-actin and smooth muscle myosin heavy chains, and contracts in response to chemical and mechanical stimuli. However, it is able to revert to a proliferative and secretory active state equivalent to that seen during vasculogenesis in the fetus, and this is a prerequisite for the involvement of the smooth muscle cell in the formation of atherosclerotic and restenotic lesions. A similar transition from a contractile to a synthetic phenotype occurs when smooth muscle cells are established in culture. Accordingly, an in vitro system has been used extensively to study the regulation of differentiated properties and proliferation of these cells. During the first few days after seeding, the cells are reorganized structurally with a loss of myofilaments and formation of a widespread endoplasmic reticulum and a prominent Golgi complex. In parallel, they lose their contractility and instead become competent to divide in response to a large variety of mitogens, including platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF). After entering the cell cycle, they start to produce these and other mitogens on their own, and continue to replicate in the absence of exogenous stimuli for a restricted number of generations. Furthermore, they start to secrete extracellular matrix components such as collagen, elastin, and proteoglycans. The mechanisms that control this change in morphology and function of the smooth muscle cells are still poorly understood. Adhesive proteins such as fibronectin and laminin apparently have an important role in determining the basic phenotypic state of the cells and exert their effects via integrin receptors. The proliferative and secretory activities of the cells are influenced by a multitude of growth factors, cytokines, and other molecules. Although much work remains before an integrated view of this regulatory machinery can be achieved, there is no doubt that the cell culture technique has contributed substantially to our knowledge of smooth muscle differentiation and growth. At the same time, it has been crucial in exploring the role of these cells in vascular disease and developing new therapeutic strategies to cope with major causes of human death and disability.
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Affiliation(s)
- J Thyberg
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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37
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Geley S, Fiegl M, Hartmann BL, Kofler R. Genes mediating glucocorticoid effects and mechanisms of their regulation. Rev Physiol Biochem Pharmacol 1996; 128:1-97. [PMID: 8791720 DOI: 10.1007/3-540-61343-9_7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- S Geley
- Institute for General and Experimental Pathology, University of Innsbruck Medical School, Austria
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38
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Abstract
PDGF is an important polypeptide growth factor that plays an essential role during early vertebrate development and is associated with tissue repair and wound healing in the adult vertebrate. Moreover, PDGF is thought to play a role in a variety of pathological phenomena, such as cancer, fibrosis and atherosclerosis. PDGF is expressed as a dimer of A and/or B chains, the precursors of which are encoded by two single copy genes. Although the PDGF genes are expressed coordinately in a number of cell types, they are independently expressed in a majority of cell types. The expression of either PDGF gene can be affected by very diverse extracellular stimuli and the type of response is dependent on the cell type that is exposed to the stimulus. Expression of the PDGF chains can be modulated at every imaginable level: by regulating accessibility of the transcription start site, by varying the transcription initiation rate, by using alternative transcription start sites, by alternative splicing, by using alternative polyadenylation signals, by varying mRNA decay rates, by regulating efficiency of translation, by protein modification, and by regulating secretion. Even upon secretion, the activity of PDGF can be modulated by non-specific or specific PDGF-binding proteins. This review provides an overview of the cell types in which the PDGF genes are expressed, of the factors that are known to affect the expression of PDGF, and of the various levels at which the expression of PDGF genes can be regulated.
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Affiliation(s)
- R P Dirks
- Department of Molecular Biology, University of Nijmegen, The Netherlands
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39
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Stewart AG, Fernandes D, Tomlinson PR. The effect of glucocorticoids on proliferation of human cultured airway smooth muscle. Br J Pharmacol 1995; 116:3219-26. [PMID: 8719799 PMCID: PMC1909167 DOI: 10.1111/j.1476-5381.1995.tb15127.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
1. Airway smooth muscle proliferation is a significant component of the airway wall remodelling that occurs in asthma. In this study, the effects of glucocorticoids on mitogenic responses of human airway smooth muscle have been examined. 2. Pretreatment of smooth muscle cells with dexamethasone (100 nM, 60 min) inhibited thrombin-induced increases in [3H]-thymidine incorporation (DNA synthesis) and cell number. 3. Inhibition of thrombin-induced [3H]-thymidine incorporation was also observed with hydrocortisone (0.01-1 microM) and methylprednisolone (0.001-0.1 microM) pretreatment. In contrast, pretreatment with either testosterone (0.001-1 microM) progesterone (0.001-1 microM), 17 beta-oestradiol (0.001-1 microM), or aldosterone (0.001-1 microM) had no effect on the response to thrombin. 4. Responses to a range of mitogens including thrombin (0.01-. 10 u ml-1), epidermal growth factor (EGF, 3-3000 pM), basic fibroblast growth factor (bFGF, 0.3-300 pM) and foetal calf serum (FCS, 0.1-10% v/v) were inhibited by dexamethasone (100 nM) pretreatment. However, the magnitude of the inhibitory effect was dependent on the mitogen, with EGF being the least, and thrombin being the most sensitive to the inhibitory effect. 5. The potency of hydrocortisone as an inhibitor of [3H]-thymidine incorporation was reduced when FCS (10% v/v, which caused a 40 fold increase in [3H]-thymidine incorporation) was used as the mitogen in place of thrombin (0.3 u ml-1, which caused a 10 fold increase in [3H]-thymidine incorporation). 6. The effect of post-treatment with dexamethasone (100 nM) indicated that addition of the glucocorticoid up to 17-19 h after thrombin (0.3 u ml-1) produced similar degrees of inhibition to those obtained when it was added as a pretreatment. Dexamethasone no longer produced an inhibitory effect if added 21 h or more after the addition of thrombin. 7. These results suggest that glucocorticoids regulate airway smooth muscle proliferation initiated by a range of stimuli. This effect may be of importance in the therapeutic actions of these compounds in asthma, particularly when they are used for prolonged periods of time.
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Affiliation(s)
- A G Stewart
- Bernard O'Brien Institute of Microsurgery, St Vincent's Hospital, Fitzroy, Victoria, Australia
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40
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Affiliation(s)
- G Fager
- Wallenberg Laboratory for Cardiovascular Research, Sahlgren's Hospital, Göteborg, Sweden
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41
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McCarthy SA, Samuels ML, Pritchard CA, Abraham JA, McMahon M. Rapid induction of heparin-binding epidermal growth factor/diphtheria toxin receptor expression by Raf and Ras oncogenes. Genes Dev 1995; 9:1953-64. [PMID: 7649477 DOI: 10.1101/gad.9.16.1953] [Citation(s) in RCA: 154] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have used differential display PCR to search for mRNAs induced by delta Raf-1:ER, an estradiol-dependent form of Raf-1 kinase. Through this approach the gene encoding heparin-binding epidermal growth factor (HB-EGF) was identified as an immediate-early transcriptional target of oncogenic Raf kinases. Activation of delta Raf-1:ER and a conditional oncogenic form of B-Raf, delta B-RAF:ER, resulted in rapid and sustained induction of HB-EGF mRNA expression and secretion of mature HB-EGF from cells. Neutralizing anti-HB-EGF antisera prevented the delayed activation of the c-Jun amino-terminal kinases that is observed in cells transformed by delta Raf-1:ER. These results demonstrate that distinct signaling pathways can cross talk via the secretion of polypeptide growth factors. Furthermore, cells transformed by oncogenic Ras, which also induced HB-EGF expression, demonstrated a marked increase in sensitivity to the cytotoxic action of diphtheria toxin, for which the membrane anchored HB-EGF precursor acts as a cell-surface receptor.
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Affiliation(s)
- S A McCarthy
- DNAX Research Institute, Palo Alto, California 94304, USA
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42
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Chen X, Raab G, Deutsch U, Zhang J, Ezzell RM, Klagsbrun M. Induction of heparin-binding EGF-like growth factor expression during myogenesis. Activation of the gene by MyoD and localization of the transmembrane form of the protein on the myotube surface. J Biol Chem 1995; 270:18285-94. [PMID: 7629148 DOI: 10.1074/jbc.270.31.18285] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Heparin-binding epidermal growth factor-like growth factor (HB-EGF) gene expression and protein localization were analyzed during the process of myogenic differentiation. The mouse HB-EGF gene was isolated, and a 1.8-kilobase genomic fragment flanking the 5' end of the cDNA was cloned. This fragment contains two sequences which match the consensus CANNTG sequence for E-boxes, binding sites for the MyoD family of DNA-binding transcription factors that regulate myogenesis. Accordingly, HB-EGF synthesis was analyzed in 10T1/2 cells and C2C12 cells which are used commonly for the study of myogenesis. HB-EGF gene expression was upregulated in both cell types during myogenesis. In 10T1/2 cells, direct activation of HB-EGF gene expression by MyoD was shown in that: i) transient transfection of these cells with a plasmid expressing MyoD resulted in a 10-20-fold increase in endogenous HB-EGF mRNA levels; ii) co-transfection of MyoD and an HB-EGF promoter-reporter plasmid resulted in a 5-10-fold increase in reporter activity, an increase that was abrogated by deletion of a putative HB-EGF proximal E-box sequence; and iii) incubation of MyoD protein with a 25-base pair double-stranded oligonucleotide corresponding to the HB-EGF proximal E-box sequence resulted in retarded electrophoretic mobility of the oligonucleotide. In C2C12 cells, differentiation of myoblasts into myotubes resulted in a 40-50-fold increase in HB-EGF promoter activity. In addition, immunostaining and laser confocal microscopy detected HB-EGF protein in C2C12 myotubes but not in myoblasts. The HB-EGF produced was in its transmembrane form and localized to the myotube surface. Taken together, it was concluded that during skeletal muscle cell differentiation, MyoD plays a direct role in activating HB-EGF gene expression and that HB-EGF protein is expressed preferentially in myotubes and in its membrane-anchored form.
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Affiliation(s)
- X Chen
- Department of Surgery, Children's Hospital, Boston, Massachusetts 02115, USA
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43
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Pan Z, Kravchenko VV, Ye RD. Platelet-activating factor stimulates transcription of the heparin-binding epidermal growth factor-like growth factor in monocytes. Correlation with an increased kappa B binding activity. J Biol Chem 1995; 270:7787-90. [PMID: 7713868 DOI: 10.1074/jbc.270.14.7787] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Human peripheral blood monocytes responded to stimulation of platelet-activating factor (PAF) with up-regulation of the transcript for heparin-binding epidermal growth factor-like growth factor (HB-EGF), a potent mitogen for vascular smooth muscle cells. This function of PAF was observed at nanomolar concentrations of the ligand, starting at 30 min after stimulation. The PAF-induced up-regulation of HB-EGF mRNA was accompanied by an increase in kappa B binding activity. These functions of PAF appeared to be mediated through the cell surface PAF receptors, as two PAF receptor antagonists, WEB 2086 and L-659,989, blocked both the up-regulation of HB-EGF mRNA and kappa B binding activity induced by PAF. The antagonists, however, had no effect on phorbol ester-induced up-regulation of HB-EGF mRNA and kappa B binding activity. Pretreatment of monocytes with pertussis toxin inhibited these functions of PAF, whereas cholera toxin had no inhibitory effect. Pyrrolidine dithiocarbamate, an inhibitor for NF-kappa B activation, markedly reduced PAF-stimulated kappa B binding activity as well as up-regulation of HB-EGF mRNA. These results suggest a potential role of PAF in HB-EGF expression and provide evidence that this stimulation may occur through increased kappa B binding activity.
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Affiliation(s)
- Z Pan
- Department of Immunology, Scripps Research Institute, La Jolla, California 92037, USA
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44
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Nakano T, Higashino K, Kikuchi N, Kishino J, Nomura K, Fujita H, Ohara O, Arita H. Vascular smooth muscle cell-derived, Gla-containing growth-potentiating factor for Ca(2+)-mobilizing growth factors. J Biol Chem 1995; 270:5702-5. [PMID: 7890695 DOI: 10.1074/jbc.270.11.5702] [Citation(s) in RCA: 143] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Proliferation of vascular smooth muscle cells (VSMC) is triggered by two types of growth factors. One activates tyrosine kinase-type receptors and the other activates G-protein-coupled receptors. We found that a conditioned medium of rat VSMC contained a growth-potentiating activity for the latter type of growth factor, and we purified a 70-kDa growth-potentiating factor (GPF) from the conditioned medium. Analyses of GPF and its cDNA revealed GPF to be a gamma-carboxyglutamic acid-containing protein encoded by a growth arrest-specific gene, gas6, which related to protein S. GPF specifically potentiated cell proliferation mediated by Ca(2+)-mobilizing receptors. The presence of a specific binding site suggests that the effect of GPF is mediated by a receptor. Thus, GPF may be a new type of extracellular factor regulating VSMC proliferation.
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MESH Headings
- Amino Acid Sequence
- Animals
- Calcium/metabolism
- Cell Division/drug effects
- Cells, Cultured
- Chromatography, Gel
- Chromatography, Ion Exchange
- Culture Media, Conditioned
- DNA/biosynthesis
- Epidermal Growth Factor/pharmacology
- Humans
- Intercellular Signaling Peptides and Proteins
- Kinetics
- Mice
- Molecular Sequence Data
- Molecular Weight
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Protein Biosynthesis
- Proteins/isolation & purification
- Proteins/metabolism
- Rats
- Receptors, Cell Surface/metabolism
- Sequence Homology, Amino Acid
- Thrombin/pharmacology
- Ultrafiltration
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Affiliation(s)
- T Nakano
- Shionogi Research Laboratories, Shionogi & Co., Ltd., Osaka, Japan
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45
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Moses MA, Klagsbrun M, Shing Y. The role of growth factors in vascular cell development and differentiation. INTERNATIONAL REVIEW OF CYTOLOGY 1995; 161:1-48. [PMID: 7558689 DOI: 10.1016/s0074-7696(08)62495-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The control of vascular growth and differentiation is a complex system of activity and interaction between positive and negative modulators of these processes. A number of important stimulators and inhibitors of both smooth muscle cells and endothelial cells have now been purified and biochemically characterized. Imbalances in the activity of these factors can result in serious pathologies. In this chapter, we briefly discuss the biology of blood vessel development and growth, review the current literature which describes these stimulators and inhibitors, and discuss current therapeutic strategies designed around these growth modulators.
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Affiliation(s)
- M A Moses
- Department of Surgery, Harvard Medical School, Boston, Massachusetts 02115, USA
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46
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Abstract
Glucocorticoids play an important role in the normal regulation of bone remodeling; however continued exposure of bone to glucocorticoid excess results in osteoporosis. In vivo, glucocorticoids stimulate bone resorption and decrease bone formation, and in vitro studies have shown that while glucocorticoids stimulate osteoblastic differentiation, they have important inhibitory actions on bone formation. Glucocorticoids have many effects on osteoblast gene expression, including down-regulation of type I collagen and osteocalcin, and up-regulation of interstitial collagenase. The synthesis and activity of osteoblast growth factors can be modulated by glucocorticoids as well. For example, insulin-like growth factor I (IGF-I) is an important stimulator of osteoblast function, and expression of IGF-I is decreased by glucocorticoids. The activity of IGF I can be modified by IGF binding proteins (IGFBPs), and their synthesis is also regulated by glucocorticoids. Thus, glucocorticoid action on osteoblasts can be direct, by activating or repressing osteoblast gene expression, or indirect by altering the expression or activity of osteoblast growth factors. Further investigation of the mechanisms by which glucocorticoids modulate gene expression in bone cells will contribute to our understanding of steroid hormone biology and will provide a basis for the design of effective treatments for glucocorticoid-induced osteoporosis.
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Affiliation(s)
- A M Delany
- Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105
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