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Remesal A, De Luca D, San Feliciano L, Isidoro-Garcia M, Minucci A, Pocino K, Casas J, Fabrias G, Capoluongo ED, de la Cruz DL. Effect of prenatal steroidal inhibition of sPLA2 in a rat model of preterm lung. Pulm Pharmacol Ther 2016; 36:31-6. [DOI: 10.1016/j.pupt.2015.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/01/2015] [Accepted: 12/07/2015] [Indexed: 10/22/2022]
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Menschikowski M, Hagelgans A, Heyne B, Hempel U, Neumeister V, Goez P, Jaross W, Siegert G. Statins potentiate the IFN-γ-induced upregulation of group IIA phospholipase A2 in human aortic smooth muscle cells and HepG2 hepatoma cells. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1733:157-71. [PMID: 15863363 DOI: 10.1016/j.bbalip.2005.01.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Revised: 12/20/2004] [Accepted: 01/10/2005] [Indexed: 01/06/2023]
Abstract
The present study shows that the incubation of human aortic smooth muscle cells (HASMC) and HepG2 cells with atorvastatin and mevastatin as HMG-CoA reductase inhibitors potentiated the interferon-gamma (INF-gamma)-induced group IIA phospholipase A(2) (sPLA(2)-IIA) expression in a dose- and time-dependent manner. The effect of statins on sPLA(2)-IIA expression was reduced by mevalonate, farnesyl pyrophosphate and geranylgeranyl pyrophosphate. Inversely, inhibitors of the farnesyl transferase and geranylgeranyl transferase-I mimicked the effects of statins. Clostridium difficile toxin B (TcdB), Y-27632 and H-1152, functioning as inhibitors of Rho proteins and Rho-associated kinase, also augmented the sPLA(2)-IIA expression in combination with IFN-gamma. The same effects were observed when inhibitors of mitogen-activated/extracellular response protein kinase kinase (MEK), PD98059 or U0126 were used. Further, the Janus kinase-2 (Jak2)-specific inhibitor, AG-490 and inhibitors of nuclear factor-kappaB (NFkappaB) abrogated the sPLA(2)-IIA elevating effects of statins, TcdB and PD98059 in the presence of IFN-gamma. This cytokine alone increased the NFkappaB p65 and CAAT-enhancer-binding protein-beta (C/EBP-beta) activity in HASMC nuclear extract, but only C/EBP-beta was further augmented when the cells were incubated in addition to IFN-gamma with atorvastatin, H-1152, PD98059 or U0126. Moreover, after the incubation of cells with atorvastatin and IFN-gamma the stability of sPLA-(2)IIA mRNA significantly increased in comparison to those after incubation with IFN-gamma alone. In conclusion, the obtained data suggest that (i) the expression of sPLA(2)-IIA is negatively regulated by RhoA/Rho-associated kinase and MEK/ERK signaling pathways and (ii) statins, because of their ability to down-regulate these pathways, can potentiate the IFN-gamma-induced sPLA(2)-II expression at transcriptional and post-transcriptional levels.
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Affiliation(s)
- Mario Menschikowski
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Institut für Klinische Chemie und Laboratoriumsmedizin, Germany.
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Vance DE, Spener F. Henk van den Bosch: chemist and biochemist. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1636:77-81. [PMID: 15164754 DOI: 10.1016/j.bbalip.2003.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Accepted: 12/05/2003] [Indexed: 11/19/2022]
Abstract
Henk van den Bosch is a native of The Netherlands and recently retired from his position as Professor at Utrecht University. This article summarizes the many scientific achievements of Dr. van den Bosch. He enjoys an international reputation for his research on phospholipases A, cardiolipin biosynthesis in eukaryotes, lysophospholipases, phosphatidylcholine biosynthesis for lung surfactant, plasmalogen biosynthesis in peroxisomes, diagnosis of peroxisomal disorders and most recently his work on alkyl-dihydroxyacetone phosphate synthase. During his research career Henk van den Bosch published approximately 280 articles and presented 110 invited lectures.
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Affiliation(s)
- Dennis E Vance
- Department of Biochemistry, Canadian Institutes of Health Research Group on Molecular and Cell Biology of Lipids, Faculty of Medicine, University of Alberta, 328 Heritage Medical Research Centre, Edmonton, Alberta, Canada T6H 5S3.
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Eberhardt W, Engels C, Müller R, Pfeilschifter J. Mechanisms of dexamethasone-mediated inhibition of cAMP-induced tPA expression in rat mesangial cells. Kidney Int 2002; 62:809-21. [PMID: 12164863 DOI: 10.1046/j.1523-1755.2002.00538.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Glucocorticoids are efficiently used as antiinflammatory and immunosuppressive therapies of renal diseases. However, long-term treatment often is associated with net changes in the turnover of extracellular matrix (ECM) components. METHODS We examined the impact of glucocorticoids on cAMP-triggered expression of tissue plasminogen activator (tPA), a protease prominently involved in glomerular ECM turnover. RESULTS By ELISA, the db-cAMP-mediated increase in extracellular tPA activity secreted by mesangial cells (MC) was markedly reduced in the presence of 100 nmol/L dexamethasone. The decrease of enzymatic activity was accompanied by an attenuation of tPA expression, as shown by Northern blot analysis. Furthermore, dexamethasone increased the steady-state mRNA level of the tPA-inhibitor 1 (PAI-1), thereby providing an additional mode of regulation of tPA activity. Mutational analysis revealed that the inhibition of tPA expression was localized within the proximal 2.3 kb of the 5'-flanking region of the rat tPA gene and critically depended on a cAMP response element (CRE) at position -185. EMSA demonstrated that binding to this CRE was affected by dexamethasone, since the db-cAMP-caused DNA binding of CREB and C/EBPbeta-immunopositive complexes was substantially reduced by dexamethasone. In parallel, dexamethasone decreased the nuclear abundance of db-cAMP-induced C/EBPbeta and phosphorylated CREB protein without affecting the total level of either transcription factor. CONCLUSIONS Suppression of cAMP-stimulated tPA expression by glucocorticoids occurs by interference with CREB and C/EBPbeta, the major transcription factors mediating cAMP responses. These observations may provide the molecular basis for the sclerotic processes within the glomerulus often complicating chronic glucocorticoid treatment.
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Affiliation(s)
- Wolfgang Eberhardt
- Pharmazentrum Frankfurt, Klinikum der Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany.
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Tung JT, Venta PJ, Eberhart SW, Yuzbasiyan-Gurkan V, Alexander L, Caron JP. Effects of anti-arthritis preparations on gene expression and enzyme activity of cyclooxygenase-2 in cultured equine chondrocytes. Am J Vet Res 2002; 63:1134-9. [PMID: 12171167 DOI: 10.2460/ajvr.2002.63.1134] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effects of recombinant equine interleukin -1beta (reIL-1beta) and 4 anti-inflammatory compounds on the expression and activity of cyclooxygenase (COX)-2 in cultured equine chondrocytes. SAMPLE POPULATION Articular cartilage from 9 young adult horses. PROCEDURE Reverse transcriptase-polymerase chain reaction methods were used to amplify a portion of equine COX-2 to prepare a cDNA probe. Northern blot analysis was used to quantify the expression of COX-2 in first-passage cultures of equine articular chondrocytes propagated in media containing dexamethasone (DEX), phenylbutazone (PBZ), polysulfated glycosaminoglycan, and hyaluronan, each at concentrations of 10 and 100 microg/ml and each with or without reIL-1beta. A commercial immunoassay was used to determine prostaglandin E2 (PGE2) concentrations in conditioned medium of similarly treated cells to quantify COX-2 activity. RESULTS Addition of reIL-1beta increased the expression of COX-2 in a dose-dependent manner, which was paralleled by an increased concentration of PGE2 in culture medium. Concentration of PGE2 in spent medium from reIL-beta-treated chondrocytes was significantly reduced by DEX and PBZ; however, only DEX significantly reduced gene expression of COX-2. CONCLUSIONS AND CLINICAL RELEVANCE Prostaglandin E2 is considered to be an important mediator in the pathophysiologic processes of arthritis, and cultured chondrocytes respond to interleukin-1 with enhanced expression and activity of COX-2. Palliative relief in affected horses is probably attributable, in part, to inhibition of PGE2 synthesis; however, analysis of these data suggests that of the 4 compounds tested, only DEX affects pretranslational regulation of the COX-2 gene in cultured equine chondrocytes.
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Affiliation(s)
- Jayne T Tung
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824, USA
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van der Helm HA, Buijtenhuijs P, van den Bosch H. Group IIA and group V secretory phospholipase A(2): quantitative analysis of expression and secretion and determination of the localization and routing in rat mesangial cells. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1530:86-96. [PMID: 11341961 DOI: 10.1016/s1388-1981(00)00171-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mesangial cells can be induced to express group IIA and group V secretory phospholipase A(2) (sPLA(2)) at the mRNA level and at the protein level. In this report we quantitatively analyze the expression of both proteins in stimulated cells by Western blot techniques. We found that 75-80% of the total amount of synthesized group IIA sPLA(2) was secreted. The synthesized group V sPLA(2), however, was present almost exclusively intracellularly. The amount of group V present in the cell was comparable to the intracellular amount of group IIA sPLA(2). We furthermore studied the localization and routing of both proteins. Using fusion proteins of the group IIA or group V pre-sPLA(2) with green fluorescent protein it was established that both presequences are able to direct the proteins to the Golgi system. In immunofluorescence studies group V sPLA(2) expressed by rat mesangial cells was located in a punctate pattern in the cytosol with an enrichment near the nucleus. Immunofluorescent confocal laser scanning microscopy revealed that the group V and IIA sPLA(2) show partial colocalization in a Golgi-like structure in the inner part in the cell, but no colocalization was seen in the vesicles in the cytoplasm. The images also showed that group IIA sPLA(2) was located throughout the cell while group V was mainly present in the inner part of the cell. After treatment of the cells with brefeldin A or monensin the group IIA enzyme could no longer be detected, while group V sPLA(2) was still present although its localization was somewhat dependent on the treatment. Collectively, these results indicate that the two enzymes differ in both localization and routing in the cell, which underscores the hypothesis that the enzymes might have different functions.
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Affiliation(s)
- H A van der Helm
- Centre for Biomembranes and Lipid Enzymology, Department Biochemistry of Lipids, Institute of Biomembranes, Utrecht University, The Netherlands
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Andreani M, Olivier JL, Berenbaum F, Raymondjean M, Béréziat G. Transcriptional regulation of inflammatory secreted phospholipases A(2). BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1488:149-58. [PMID: 11080684 DOI: 10.1016/s1388-1981(00)00117-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Secreted phospholipases A(2) is a family of small molecular weight and calcium-dependent enzymes of which the members list is presently growing. Among these enzymes, the synovial type IIA and the type V phospholipases A(2) are involved in inflammation. Although their actual mechanism is still a subject of debate, new therapeutic strategies can result from the knowledge of the regulations of their gene expression. The human genes of the type IIA and type V phospholipases A(2) are located on the chromosome 1 at close positions and transcribed in reverse orientations. These genes can therefore be regulated by common elements but only the regulation of the type IIA phospholipase A(2) gene expression has been extensively studied. Pro-inflammatory cytokines upregulate while the growth factors downregulate the type IIA phospholipase A(2) gene expression. Interleukin-6 and interleukin-1beta exert their effects at least partially at the transcriptional level. The transcriptional regulation of the type IIA phospholipase A(2) gene is cell- and species-specific. The activity of the human promoter is controlled by the CAAT-enhancer binding protein (C/EBP) factors while that of the rat promoter is regulated by nuclear factor kappaB (NF-kappaB) and C/EBPs. Furthermore, the human promoter is constitutively repressed in hepatocytes by single strand DNA binding proteins whose effects are relieved by C/EBP factors while the glucocorticoid receptor interacts with C/EBPs in chondrocytes to achieve full basal and interleukin-1beta-stimulated transcription activity. Other factors like CTF/NF1 and Sp1 might be involved in the regulation of both the rat and human promoter. Peroxisome proliferator-activated receptors could contribute to the stimulation of the rat promoter by NF-kappaB in vascular smooth muscle cells. The study of the coactivators and coinhibitors associated to these transcription factors will give a better understanding of the diversity and complexity of the transcriptional regulations of the type IIA phospholipase A(2) gene.
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Affiliation(s)
- M Andreani
- CNRS-associated research unit of Pierre and Marie Curie University (Paris VI), ESA 7079, 7 quai Saint Bernard, 75005, Paris, France
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Scholz-Pedretti K, Eberhardt W, Rupprecht G, Beck KF, Spitzer S, Pfeilschifter J, Kaszkin M. Inhibition of NFkappaB-mediated pro-inflammatory gene expression in rat mesangial cells by the enolized 1,3-dioxane-4, 6-dione-5-carboxamide, CGP-43182. Br J Pharmacol 2000; 130:1183-90. [PMID: 10882405 PMCID: PMC1572174 DOI: 10.1038/sj.bjp.0703419] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
1. CGP-43182 has been described as a potent inhibitor of group IIA secreted phospholipase A(2) (group IIA sPLA(2)) activity in vitro. In rat mesangial cells, inhibition of group IIA sPLA(2) activity by CGP-43182 results in a 70% reduction of cytokine-stimulated prostaglandin E(2) biosynthesis, suggesting that group IIA sPLA(2) participates in arachidonic acid release and eicosanoid formation. Under these conditions the cytosolic phospholipase A(2) is not affected. 2. In mesangial cells, in addition to inhibition of catalytic activity, the membrane-permeant CGP-43182 completely blocked interleukin 1beta (IL1beta)-stimulated group IIA sPLA(2) gene expression. 3. A further action of CGP-43182 was a complete inhibition of cyclo-oxygenase-2 gene expression, resulting in a drastic reduction of prostaglandin formation in mesangial cells. 4. Moreover, CGP-43182 completely blocked IL1beta-induced gene expression of the inducible nitric oxide synthase, leading to an inhibition of cytokine-stimulated nitric oxide formation. 5. In contrast, the stimulatory effect of the cell-permeant cyclic AMP-analogue, dibutyryl-cAMP, on the induction of these enzymes was not inhibited by CGP-43182. These data indicate that CGP-43182 interferes with IL1beta- but not cyclic AMP-activated transcriptional regulation. 6. By studying components of the upstream transcription machinery, we observed an inhibition of NFkappaB activation by CGP-43182 in IL1beta-treated cells. Moreover, we observed that CGP-43182 prevented the phosphorylation and proteolytic degradation of the endogenous NFkappaB inhibitor, IkappaB, a process necessary for NFkappaB activation. 7. From our data, we propose that CGP-43182 is a potent anti-inflammatory drug useful for preventing the consequences of a concerted action of cytokine-stimulated pro-inflammatory genes mediated by NFkappaB.
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Affiliation(s)
- Kirsten Scholz-Pedretti
- Zentrum der Pharmakologie, Klinikum der Johann Wolfgang Goethe-Universität, D-60590 Frankfurt-am-Main, Germany
| | - Wolfgang Eberhardt
- Zentrum der Pharmakologie, Klinikum der Johann Wolfgang Goethe-Universität, D-60590 Frankfurt-am-Main, Germany
| | - Gerhard Rupprecht
- Medizinische Klinik IV, Funktionsbereich Nephrologie, Klinikum der Johann Wolfgang Goethe-Universität, D-60590 Frankfurt-am-Main, Germany
| | - Karl-Friedrich Beck
- Zentrum der Pharmakologie, Klinikum der Johann Wolfgang Goethe-Universität, D-60590 Frankfurt-am-Main, Germany
| | - Silke Spitzer
- Zentrum der Pharmakologie, Klinikum der Johann Wolfgang Goethe-Universität, D-60590 Frankfurt-am-Main, Germany
| | - Josef Pfeilschifter
- Zentrum der Pharmakologie, Klinikum der Johann Wolfgang Goethe-Universität, D-60590 Frankfurt-am-Main, Germany
| | - Marietta Kaszkin
- Zentrum der Pharmakologie, Klinikum der Johann Wolfgang Goethe-Universität, D-60590 Frankfurt-am-Main, Germany
- Author for correspondence:
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van der Helm HA, Aarsman AJ, Janssen MJ, Neys FW, van den Bosch H. Regulation of the expression of group IIA and group V secretory phospholipases A(2) in rat mesangial cells. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1484:215-24. [PMID: 10760471 DOI: 10.1016/s1388-1981(00)00021-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rat mesangial cells synthesize and secrete a secretory phospholipase A(2) upon stimulation of the cells with cytokines, like IL-1beta and TNF and with cAMP elevating agents like forskolin. This enzyme was previously characterized to belong to group IIA sPLA(2). The discovery of several other low molecular weight phospholipases, like group IIC in murine testis and group V in human and rat heart, prompted investigations on the presence of group IIC and group V sPLA(2) in rat mesangial cells. This was done by isolating the RNA from stimulated cells and performing RT-PCR, using primers specific for group IIC and V sPLA(2). The results indicate that rat mesangial cells upon stimulation express next to group IIA also group V sPLA(2). No indications were obtained for the expression of group IIC sPLA(2). The regulation of the expression of group V sPLA(2) at the mRNA level was further investigated by examining the time-dependent expression, the influence of dexamethasone and the signaling route of the IL-1beta stimulation. The results show that the IL-1beta induced expression of group V sPLA(2) mRNA was time dependent and, similar to that of group IIA sPLA(2) mRNA, involves activation of NF-kappaB. However, in contrast to the group IIA sPLA(2), the expression of group V sPLA(2) was not influenced by the presence of dexamethasone. The expression of both phospholipases was also examined at the protein level in stimulated mesangial cells. Western blot analysis shows that stimulated mesangial cells synthesize both group IIA and group V sPLA(2) protein but the expression of group V is lower compared to that of group IIA sPLA(2). In addition, the extent of secretion into the medium appears to be considerably higher for group IIA than for group V sPLA(2).
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Affiliation(s)
- H A van der Helm
- Biochemistry Laboratory, Centre for Biomembranes and Lipid Enzymology, Institute for Biomembranes, University of Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
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Yao XL, Cowan MJ, Gladwin MT, Lawrence MM, Angus CW, Shelhamer JH. Dexamethasone alters arachidonate release from human epithelial cells by induction of p11 protein synthesis and inhibition of phospholipase A2 activity. J Biol Chem 1999; 274:17202-8. [PMID: 10358078 DOI: 10.1074/jbc.274.24.17202] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The effect of the glucocorticosteroid, dexamethasone, on arachidonic acid (AA) release and on protein levels of p11 and cytosolic phospholipase A2 (cPLA2) was studied in two epithelial cell lines, HeLa cells and BEAS-2B cells. Dexamethasone treatment of HeLa cells and BEAS-2B cells increased cellular p11 protein and mRNA levels in a time- and dose-dependent manner. It had little effect on levels of cPLA2 protein. In order to determine if increased p11 protein expression resulted in increased interaction between p11 and cPLA2, anti-cPLA2 antibodies were used to immunoprecipitate p11.cPLA2 complexes and Western blots of the immunoprecipitate were used to detect p11. In cells treated with dexamethasone, more p11 was detected in the anti-cPLA2 immunoprecipitate compared with control cells. Dexamethasone treatment of HeLa cells prelabeled with [3H]AA decreased the release of [3H]AA under basal conditions and after stimulation with the calcium ionophore A23187 (10(-6) M). In order to determine if altering the p11 protein levels in HeLa cells independent of glucocorticosteroid treatment could also produce an effect on [3H]AA release, cells were stably transfected with plasmids expressing either p11 antisense mRNA or p11 mRNA. Cloned HeLa cells expressing p11 antisense mRNA exhibited less cellular p11 protein compared with control cells and greater [3H]AA release compared with cells transfected with a control vector. Cloned HeLa cells stably transfected with a p11 expression vector exhibited increased p11 cellular protein and diminished [3H]AA release under basal conditions and in response to A23187. Therefore, dexamethasone alteration of epithelial cell AA release may be due in part to induction of p11 protein expression.
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Affiliation(s)
- X L Yao
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA
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Abstract
The balance between local offense factors and defense machinery determines the fate of tissue injury: progression or resolution. In glomerular research, the most interest has been on the offensive side, for example, the roles of leukocytes, platelets, complement, cytokines, eicosanoids, and oxygen radical intermediates. There has been little focus on the defensive side, which is responsible for the attenuation and resolution of disease. The aim of this review is to address possible mechanisms of local defense that may be exerted during glomerular injury. Cytokine inhibitors, proteinase inhibitors, complement regulatory proteins, anti-inflammatory cytokines, anti-inflammatory eicosanoids, antithrombotic molecules, and extracellular matrix proteins can participate in the extracellular and/or cell surface defense. Heat shock proteins, antioxidants, protein phosphatases, and cyclin kinase inhibitors may contribute to the intracellular defense. This article outlines how the glomerulus, when faced with injurious cells or exposed to pathogenic mediators, defends itself via the intrinsic machinery that is brought into play in resident glomerular cells.
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Affiliation(s)
- M Kitamura
- Department of Medicine, University College London Medical School, England, United Kingdom.
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Marshall LA, Roshak AK. Utility of oligonucleotides as tools to study the function and regulation of 85 kDa phospholipase A2. ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT 1998; 8:153-7. [PMID: 9593056 DOI: 10.1089/oli.1.1998.8.153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- L A Marshall
- Department of Immunopharmacology, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406, USA
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Walker G, Kunz D, Pignat W, Pfeilschifter J. Platelet-derived growth factor and fibroblast growth factor differentially regulate interleukin 1beta- and cAMP-induced group II phospholipase A2 expression in rat renal mesangial cells. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1391:213-22. [PMID: 9555020 DOI: 10.1016/s0005-2760(97)00204-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Expression of group II phospholipase A2 (PLA2; EC 3.1.1.4) in rat renal mesangial cells is triggered in response to two principal classes of activating signals. These two groups of activators comprise inflammatory cytokines such as interleukin 1beta (IL-1beta) or tumor necrosis factor alpha and agents that elevate cellular levels of cyclic AMP (cAMP) such as forskolin, an activator of adenylate cyclase. Treatment of mesangial cells with IL-1beta or forskolin for 24 h induces group II PLA2 activity secreted into cell culture supernatants by about 15-fold and 11-fold, respectively. Platelet-derived growth factor (PDGF)-BB potently inhibits secretion of IL-1beta- and forskolin-induced group II PLA2 activity. By Western and Northern blot analyses, we demonstrate that this is due to a reduction of PLA2 protein levels and the corresponding PLA2 mRNA steady-state levels. Basic fibroblast growth factor (bFGF) virtually does not inhibit IL-1beta-stimulated group II PLA2 activity, but markedly inhibits forskolin-induced expression of group II PLA2 activity. These effects are caused by changes in the corresponding PLA2 protein and PLA2 mRNA steady-state levels. Inhibition of protein kinase C (PKC) by the potent and selective PKC inhibitor calphostin C converted the inhibitory action of PDGF into a bFGF-type of response thus suggesting that PKC is a major effector in PDGF-induced inhibition of IL-1beta-stimulated group II sPLA2 expression. In summary, our data suggest that PDGF and bFGF differentially modulate in a stimulus-specific manner the expression of group II PLA2 in mesangial cells.
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Affiliation(s)
- G Walker
- Department of Pharmacology, Biozentrum, University of Basel, Klingelbergstr. 70, CH-4056 Basel, Switzerland
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Goppelt-Struebe M, Schaefer D, Habenicht AJ. Differential regulation of cyclo-oxygenase-2 and 5-lipoxygenase-activating protein (FLAP) expression by glucocorticoids in monocytic cells. Br J Pharmacol 1997; 122:619-24. [PMID: 9375956 PMCID: PMC1564983 DOI: 10.1038/sj.bjp.0701425] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. The objective of the present study was to determine the effects of dexamethasone on key constituents of prostaglandin and leukotriene biosynthesis, cyclo-oxygenase-2 (COX-2) and 5-lipoxygenase activating protein (FLAP). The human monocytic cell line THP-1 was used as a model system. mRNA and protein levels of COX-2 and FLAP were determined by Northern and Western blot analyses, respectively. 2. Low levels of COX-2 and FLAP mRNA were expressed in undifferentiated THP-1 cells, but were induced upon differentiation of the cells along the monocytic pathway by treatment with phorbol ester (TPA, 5 nM). Maximal expression was observed after two days. 3. Coincubation of the undifferentiated cells with dexamethasone (10(-9) - 10(-6) M) and phorbol ester prevented induction of COX-2 mRNA, but did not affect the induction of FLAP mRNA. 4. Dexamethasone downregulated COX-2 mRNA and protein in differentiated, monocyte-like THP-1 cells. In contrast, FLAP mRNA and protein were upregulated by dexamethasone in differentiated THP-1 cells. After 24 h, FLAP mRNA levels were increased more than 2 fold. Dexamethasone did not change 5-lipoxygenase mRNA expression. 5. Release of prostaglandin E2 (PGE2) and peptidoleukotrienes was determined in cell culture supernatants of differentiated THP-1 cells by ELISA. Calcium ionophore-dependent PGE2 synthesis was associated with COX-2 expression, whereas COX-1 and COX-2 seemed to participate in arachidonic acid-dependent PGE2 synthesis. Very low levels of peptidoleukotrienes were released from differentiated THP-1 cells upon incubation with ionophore. Treatment with dexamethasone did not significantly affect leukotriene release. 6. These data provide evidence that prostaglandin synthesis is consistently downregulated by glucocorticoids. However, the glucocorticoid-mediated induction of FLAP may provide a mechanism to maintain leukotriene biosynthesis through more efficient transfer of arachidonic acid to the 5-lipoxygenase reaction, in spite of inhibitory effects on other enzymes of the biosynthetic pathway.
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Affiliation(s)
- M Goppelt-Struebe
- Department of Internal Medicine IV, University of Erlangen-Nürnberg, Erlangen, Germany
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Goppelt-Struebe M. Molecular mechanisms involved in the regulation of prostaglandin biosynthesis by glucocorticoids. Biochem Pharmacol 1997; 53:1389-95. [PMID: 9260864 DOI: 10.1016/s0006-2952(97)00018-x] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The anti-inflammatory properties of glucocorticoids are attributed in part, to their interference with prostaglandin synthesis. Phospholipases A2 and cyclooxygenases, the key enzymes of prostaglandin biosynthesis, are targets of glucocorticoid action; the molecular mechanisms, however, are not yet understood in detail. Obviously, glucocorticoids can act at different levels of gene regulation depending on cell type and inducing stimulus. The current knowledge of glucocorticoid interference with phospholipase A2 and cyclooxygenase expression is summarized. In comparison with other nonsteroidal anti-inflammatory drugs, glucocorticoids are unique inasmuch as they also inhibit cytokine synthesis and expression of other inflammation-related enzymes. Based on a more detailed understanding of glucocorticoid action, it may be possible to therapeutically exploit the anti-inflammatory effects and at the same time avoid the unwanted metabolic actions of these steroids.
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Wada A, Tojo H, Sugiura T, Fujiwara Y, Kamada T, Ueda N, Okamoto M. Group II phospholipase A2 as an autocrine growth factor mediating interleukin-1 action on mesangial cells. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1345:99-108. [PMID: 9084507 DOI: 10.1016/s0005-2760(96)00158-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The proliferation of mesangial cells plays a central role in the progression of glomerulonephritis. We studied the role of group II phospholipase A2 in interleukin-1-stimulated proliferation of mesangial cells. Cultured rat mesangial cells secreted 5.3 units group II phospholipase A2/24 h per 10(5) cells in response to stimulation of 200 U/ml of interleukin-1. Northern hybridization analysis showed that mRNA for group II phospholipase A2 was induced by exogenously added group II phospholipase A2 (15 U/ml) as well as interleukin-1. The pretreatment of quiescent mesangial cells with interleukin-1 augmented [3H]thymidine incorporation caused by platelet derived growth factor. Exogenous group II phospholipase A2 (5-36 U/ml) purified homogeneously from rat spleen also increased [3H]thymidine incorporation by platelet derived growth factor-stimulated mesangial cells in a dose dependent manner (36 U/ml phospholipase A2; 1.9-fold). The stimulatory effect of interleukin-1 on DNA synthesis of mesangial cells was specifically blunted by immunoglobulin raised against group II phospholipase A2. Group II phospholipase A2 (16 U/ml) amplified a platelet derived growth factor-stimulated increase in the mesangial cell number by 1.5-fold. Among the products of the phospholipase A2-catalyzed reaction, lysophospholipids including lysophosphatidylcholine, lysophosphatidylethanolamine and lysophosphatidic acid, but not fatty acids, mimicked the stimulatory effect of interleukin-1 and phospholipase A2. These results suggest that group II phospholipase A2 acts as a signaling molecule that mediates interleukin-1-induced growth of rat mesangial cells through yielding lysophospholipids.
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Affiliation(s)
- A Wada
- First Department of Medicine, Osaka University School of Medicine, Japan
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Vervoordeldonk MJ, van Rossum GS, Sanchez RM, Neys FW, van den Bosch H. Half-life of interleukin-1 beta-induced group II phospholipase A2 in rat mesangial cells. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1355:315-22. [PMID: 9061002 DOI: 10.1016/s0167-4889(96)00142-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Group II phospholipase A2 (sPLA2) has been implicated as an important agent involved in a number of inflammatory processes. Potent pro-inflammatory cytokines, such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor (TNF) have been found to induce sPLA2 synthesis and release from many cell types among which mesangial cells. Although considerable research has been devoted to unravelling the mechanisms underlying the induction of sPLA2 not much is known about the time scale at which the cytokine elicited signals for sPLA2 induction persist in target cells. In this study we addressed that question by using rat renal mesangial cells as a model target cell. We found that after removal of IL-1 beta from the culture medium, the induced-sPLA2 synthesis continues at gradually decreasing rates for approximately 8 h. This is accompanied by a decrease in sPLA2 mRNA levels. Furthermore, with pulse-chase experiments we investigated the half-life of sPLA2 disappearance from the cells. This disappearance was found to be biphasic. A rapidly disappearing pool, constituting approx. 74% of the total, exhibited a half-life of 1.6 +/- 0.2 h. The remaining pool of the induced enzyme was much more stable and its level remained constant for at least 24 h. Analysis of the appearance of newly synthesized enzyme in the culture medium indicated this process to be completed in an hour.
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Vervoordeldonk MJ, Pineda Torra IM, Aarsman AJ, van den Bosch H. Aspirin inhibits expression of the interleukin-1beta-inducible group II phospholipase A2. FEBS Lett 1996; 397:108-12. [PMID: 8941724 DOI: 10.1016/s0014-5793(96)01148-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) clearly inhibit the synthesis and release of prostaglandins. However, these actions are not sufficient to explain all the anti-inflammatory effects of these drugs. Recently, it has been shown that aspirin and sodium salicylate inhibit the activation of the transcription factor NF-kappaB. Group II phospholipase A2 (sPLA2) is expressed in rat glomerular mesangial cells upon exposure to the inflammatory cytokine interleukin-1beta (IL-1beta) and this induction is attenuated by the NF-kappaB inhibitor pyrrolidine dithiocarbamate (PDTC). We now report that aspirin inhibits the IL-1beta-induced sPLA2 activity in rat mesangial cells in a dose-dependent manner. The IC50 value of aspirin for sPLA2 inhibition was 6.5 mM. This decrease in sPLA2 activity was not due to direct inhibition of enzymatic activity but rather to the fact that aspirin inhibits the expression of IL-1beta-induced sPLA2 protein and mRNA. Furthermore, by electrophoretic mobility shift analysis we demonstrate reduced DNA binding of the nuclear factor kappaB, an essential component of the IL-1beta-dependent upregulation of sPLA2 gene transcription, after treatment of the cells with aspirin. The study described in this report indicates that the inhibition of sPLA2 expression as induced by pro-inflammatory cytokines potentially represents an additional mechanism of action for aspirin.
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Affiliation(s)
- M J Vervoordeldonk
- Centre for Biomembranes and Lipid Enzymology, Institute for Biomembranes, Utrecht, The Netherlands
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