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Kountz TS, Jairaman A, Kountz CD, Stauderman KA, Schleimer RP, Prakriya M. Differential Regulation of ATP- and UTP-Evoked Prostaglandin E 2 and IL-6 Production from Human Airway Epithelial Cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2021; 207:1275-1287. [PMID: 34389624 PMCID: PMC8816324 DOI: 10.4049/jimmunol.2100127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 07/07/2021] [Indexed: 11/19/2022]
Abstract
The airway epithelial cells (AECs) lining the conducting passageways of the lung secrete a variety of immunomodulatory factors. Among these, PGE2 limits lung inflammation and promotes bronchodilation. By contrast, IL-6 drives intense airway inflammation, remodeling, and fibrosis. The signaling that differentiates the production of these opposing mediators is not understood. In this study, we find that the production of PGE2 and IL-6 following stimulation of human AECs by the damage-associated molecular pattern extracellular ATP shares a common requirement for Ca2+ release-activated Ca2+ (CRAC) channels. ATP-mediated synthesis of PGE2 required activation of metabotropic P2Y2 receptors and CRAC channel-mediated cytosolic phospholipase A2 signaling. By contrast, ATP-evoked synthesis of IL-6 occurred via activation of ionotropic P2X receptors and CRAC channel-mediated calcineurin/NFAT signaling. In contrast to ATP, which elicited the production of both PGE2 and IL-6, the uridine nucleotide, UTP, stimulated PGE2 but not IL-6 production. These results reveal that human AECs employ unique receptor-specific signaling mechanisms with CRAC channels as a signaling nexus to regulate release of opposing immunomodulatory mediators. Collectively, our results identify P2Y2 receptors, CRAC channels, and P2X receptors as potential intervention targets for airway diseases.
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Affiliation(s)
- Timothy S Kountz
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Amit Jairaman
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Candace D Kountz
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | | | - Robert P Schleimer
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL;
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
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2
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He RP, Jin Z, Ma RY, Hu FD, Dai JY. Network pharmacology unveils spleen-fortifying effect of Codonopsis Radix on different gastric diseases based on theory of “same treatment for different diseases” in traditional Chinese medicine. CHINESE HERBAL MEDICINES 2021; 13:189-201. [PMID: 36117498 PMCID: PMC9476800 DOI: 10.1016/j.chmed.2020.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/13/2020] [Accepted: 10/23/2020] [Indexed: 12/08/2022] Open
Abstract
Objective Methods Results Conclusion
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3
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Berhan A, Harris T, Jaffar J, Jativa F, Langenbach S, Lönnstedt I, Alhamdoosh M, Ng M, Lee P, Westall G, Wilson N, Wilson M, Stewart AG. Cellular Microenvironment Stiffness Regulates Eicosanoid Production and Signaling Pathways. Am J Respir Cell Mol Biol 2021; 63:819-830. [PMID: 32926636 DOI: 10.1165/rcmb.2020-0227oc] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Pathological changes in the biomechanical environment are implicated in the progression of idiopathic pulmonary fibrosis (IPF). Stiffened matrix augments fibroblast proliferation and differentiation and activates TGF-β1 (transforming growth factor-β1). Stiffened matrix impairs the synthesis of the antifibrogenic lipid mediator prostaglandin E2 (PGE2) and reduces the expression of the rate-limiting prostanoid biosynthetic enzyme cyclooxygenase-2 (COX-2). We now show that prostaglandin E synthase (PTGES), the final enzyme in the PGE2 biosynthetic pathway, is expressed at lower levels in the lungs of patients with IPF. We also show substantial induction of COX-2, PTGES, prostaglandin E receptor 4 (EP4), and cytosolic phospholipase A2 (cPLA2) expression in human lung fibroblasts cultured in soft collagen hydrogels or in spheroids compared with conventional culture on stiff plastic culture plates. Induction of COX-2, cPLA2, and PTGES expression in spheroid cultures was moderately inhibited by the p38 mitogen-activated protein kinase inhibitor SB203580. The induction of prostanoid biosynthetic enzyme expression was accompanied by an increase in PGE2 levels only in non-IPF-derived fibroblast spheroids. Our study reveals an extensive dysregulation of prostanoid biosynthesis and signaling pathways in IPF-derived fibroblasts, which are only partially abrogated by culture in soft microenvironments.
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Affiliation(s)
- Asres Berhan
- Department of Pharmacology and Therapeutics, and
| | - Trudi Harris
- Department of Pharmacology and Therapeutics, and
| | - Jade Jaffar
- Department of Allergy, Immunology, Respiratory Medicine, The Alfred Hospital/Monash University, Melbourne, Victoria, Australia
| | - Fernando Jativa
- Department of Pharmacology and Therapeutics, and.,Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | | | | | | | - Milica Ng
- CSL Ltd., Melbourne, Victoria, Australia; and
| | - Peter Lee
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Glen Westall
- Department of Allergy, Immunology, Respiratory Medicine, The Alfred Hospital/Monash University, Melbourne, Victoria, Australia
| | - Nick Wilson
- CSL Ltd., Melbourne, Victoria, Australia; and
| | | | - Alastair G Stewart
- Department of Pharmacology and Therapeutics, and.,ARC Centre for Personalised Therapeutics Technologies, Melbourne, Victoria, Australia
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4
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Ansarey SH. Inflammation and JNK's Role in Niacin-GPR109A Diminished Flushed Effect in Microglial and Neuronal Cells With Relevance to Schizophrenia. Front Psychiatry 2021; 12:771144. [PMID: 34916973 PMCID: PMC8668869 DOI: 10.3389/fpsyt.2021.771144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 11/02/2021] [Indexed: 12/28/2022] Open
Abstract
Schizophrenia is a neuropsychiatric illness with no single definitive aetiology, making its treatment difficult. Antipsychotics are not fully effective because they treat psychosis rather than the cognitive or negative symptoms. Antipsychotics fail to alleviate symptoms when patients enter the chronic stage of illness. Topical application of niacin showed diminished skin flush in the majority of patients with schizophrenia compared to the general population who showed flushing. The niacin skin flush test is useful for identifying patients with schizophrenia at their ultra-high-risk stage, and understanding this pathology may introduce an effective treatment. This review aims to understand the pathology behind the diminished skin flush response, while linking it back to neurons and microglia. First, it suggests that there are altered proteins in the GPR109A-COX-prostaglandin pathway, inflammatory imbalance, and kinase signalling pathway, c-Jun N-terminal kinase (JNK), which are associated with diminished flush. Second, genes from the GPR109A-COX-prostaglandin pathway were matched against the 128-loci genome wide association study (GWAS) for schizophrenia using GeneCards, suggesting that G-coupled receptor-109A (GPR109A) may have a genetic mutation, resulting in diminished flush. This review also suggests that there may be increased pro-inflammatory mediators in the GPR109A-COX-prostaglandin pathway, which contributes to the diminished flush pathology. Increased levels of pro-inflammatory markers may induce microglial-activated neuronal death. Lastly, this review explores the role of JNK on pro-inflammatory mediators, proteins in the GPR109A-COX-prostaglandin pathway, microglial activation, and neuronal death. Inhibiting JNK may reverse the changes observed in the diminished flush response, which might make it a good therapeutic target.
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Affiliation(s)
- Sabrina H Ansarey
- Department of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom
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5
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Pěnčíková K, Svržková L, Strapáčová S, Neča J, Bartoňková I, Dvořák Z, Hýžďalová M, Pivnička J, Pálková L, Lehmler HJ, Li X, Vondráček J, Machala M. In vitro profiling of toxic effects of prominent environmental lower-chlorinated PCB congeners linked with endocrine disruption and tumor promotion. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:473-486. [PMID: 29518658 PMCID: PMC5908724 DOI: 10.1016/j.envpol.2018.02.067] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/20/2018] [Accepted: 02/20/2018] [Indexed: 05/18/2023]
Abstract
The mechanisms contributing to toxic effects of airborne lower-chlorinated PCB congeners (LC-PCBs) remain poorly characterized. We evaluated in vitro toxicities of environmental LC-PCBs found in both indoor and outdoor air (PCB 4, 8, 11, 18, 28 and 31), and selected hydroxylated metabolites of PCB 8, 11 and 18, using reporter gene assays, as well as other functional cellular bioassays. We focused on processes linked with endocrine disruption, tumor promotion and/or regulation of transcription factors controlling metabolism of both endogenous compounds and xenobiotics. The tested LC-PCBs were found to be mostly efficient anti-androgenic (within nanomolar - micromolar range) and estrogenic (at micromolar concentrations) compounds, as well as inhibitors of gap junctional intercellular communication (GJIC) at micromolar concentrations. PCB 8, 28 and 31 were found to partially inhibit the aryl hydrocarbon receptor (AhR)-mediated activity. The tested LC-PCBs were also partial constitutive androstane receptor (CAR) and pregnane X receptor (PXR) agonists, with PCB 4, 8 and 18 being the most active compounds. They were inactive towards other nuclear receptors, such as vitamin D receptor, thyroid receptor α, glucocorticoid receptor or peroxisome proliferator-activated receptor γ. We found that only PCB 8 contributed to generation of oxidative stress, while all tested LC-PCBs induced arachidonic acid release (albeit without further modulations of arachidonic acid metabolism) in human lung epithelial cells. Importantly, estrogenic effects of hydroxylated (OH-PCB) metabolites of LC-PCBs (4-OH-PCB 8, 4-OH-PCB 11 and 4'-OH-PCB 18) were higher than those of the parent PCBs, while their other toxic effects were only slightly altered or suppressed. This suggested that metabolism may alter toxicity profiles of LC-PCBs in a receptor-specific manner. In summary, anti-androgenic and estrogenic activities, acute inhibition of GJIC and suppression of the AhR-mediated activity were found to be the most relevant modes of action of airborne LC-PCBs, although they partially affected also additional cellular targets.
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Affiliation(s)
- Kateřina Pěnčíková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Lucie Svržková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Simona Strapáčová
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Jiří Neča
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Iveta Bartoňková
- Department of Cell Biology and Genetics, Faculty of Science, Šlechtitelů 11, Palacký University, 78371 Olomouc, Czech Republic
| | - Zdeněk Dvořák
- Department of Cell Biology and Genetics, Faculty of Science, Šlechtitelů 11, Palacký University, 78371 Olomouc, Czech Republic
| | - Martina Hýžďalová
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic; Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic
| | - Jakub Pivnička
- Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic
| | - Lenka Pálková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, 52242, IA, USA
| | - Xueshu Li
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, 52242, IA, USA
| | - Jan Vondráček
- Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic.
| | - Miroslav Machala
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic.
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6
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Zagryazhskaya A, Surova O, Akbar NS, Allavena G, Gyuraszova K, Zborovskaya IB, Tchevkina EM, Zhivotovsky B. Tudor staphylococcal nuclease drives chemoresistance of non-small cell lung carcinoma cells by regulating S100A11. Oncotarget 2016; 6:12156-73. [PMID: 25940438 PMCID: PMC4494929 DOI: 10.18632/oncotarget.3495] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/07/2015] [Indexed: 12/20/2022] Open
Abstract
Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC), the major lung cancer subtype, is characterized by high resistance to chemotherapy. Here we demonstrate that Tudor staphylococcal nuclease (SND1 or TSN) is overexpressed in NSCLC cell lines and tissues, and is important for maintaining NSCLC chemoresistance. Downregulation of TSN by RNAi in NSCLC cells led to strong potentiation of cell death in response to cisplatin. Silencing of TSN was accompanied by a significant decrease in S100A11 expression at both mRNA and protein level. Downregulation of S100A11 by RNAi resulted in enhanced sensitivity of NSCLC cells to cisplatin, oxaliplatin and 5-fluouracil. AACOCF3, a phospholipase A2 (PLA2) inhibitor, strongly abrogated chemosensitization upon silencing of S100A11 suggesting that PLA2 inhibition by S100A11 governs the chemoresistance of NSCLC. Moreover, silencing of S100A11 stimulated mitochondrial superoxide production, which was decreased by AACOCF3, as well as N-acetyl-L-cysteine, which also mimicked the effect of PLA2 inhibitor on NSCLC chemosensitization upon S100A11 silencing. Thus, we present the novel TSN-S100A11-PLA2 axis regulating superoxide-dependent apoptosis, triggered by platinum-based chemotherapeutic agents in NSCLC that may be targeted by innovative cancer therapies.
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Affiliation(s)
- Anna Zagryazhskaya
- Institute of Environmental Medicine, Division of Toxicology, Stockholm, Sweden
| | - Olga Surova
- Institute of Environmental Medicine, Division of Toxicology, Stockholm, Sweden.,Ludwig Institute for Cancer Research Ltd, Karolinska Institutet, Stockholm, Sweden
| | - Nadeem S Akbar
- Institute of Environmental Medicine, Division of Toxicology, Stockholm, Sweden
| | - Giulia Allavena
- Institute of Environmental Medicine, Division of Toxicology, Stockholm, Sweden.,Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Katarina Gyuraszova
- Institute of Environmental Medicine, Division of Toxicology, Stockholm, Sweden.,Institute of Biology and Ecology, Faculty of Science, Pavol Jozef Šafárik University in Košice, Košice, Slovakia
| | - Irina B Zborovskaya
- NN Blokhin Russian Cancer Research Center, Moscow, Russia.,Faculty of Fundamental Medicine, ML Lomonosov State University, Moscow, Russia
| | - Elena M Tchevkina
- NN Blokhin Russian Cancer Research Center, Moscow, Russia.,Faculty of Fundamental Medicine, ML Lomonosov State University, Moscow, Russia
| | - Boris Zhivotovsky
- Institute of Environmental Medicine, Division of Toxicology, Stockholm, Sweden.,Faculty of Fundamental Medicine, ML Lomonosov State University, Moscow, Russia
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7
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Chronic neuroinflammation in Alzheimer's disease: new perspectives on animal models and promising candidate drugs. BIOMED RESEARCH INTERNATIONAL 2014; 2014:309129. [PMID: 25025046 PMCID: PMC4083880 DOI: 10.1155/2014/309129] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/14/2014] [Accepted: 05/14/2014] [Indexed: 12/03/2022]
Abstract
Chronic neuroinflammation is now considered one of the major factors in the pathogenesis of Alzheimer's disease (AD). However, the most widely used transgenic AD models (overexpressing mutated forms of amyloid precursor protein, presenilin, and/or tau) do not demonstrate the degree of inflammation, neurodegeneration (particularly of the cholinergic system), and cognitive decline that is comparable with the human disease. Hence a more suitable animal model is needed to more closely mimic the resulting cognitive decline and memory loss in humans in order to investigate the effects of neuroinflammation on neurodegeneration. One of these models is the glial fibrillary acidic protein-interleukin 6 (GFAP-IL6) mouse, in which chronic neuroinflammation triggered constitutive expression of the cytokine interleukin-6 (IL-6) in astrocytes. These transgenic mice show substantial and progressive neurodegeneration as well as a decline in motor skills and cognitive function, starting from 6 months of age. This animal model could serve as an excellent tool for drug discovery and validation in vivo. In this review, we have also selected three potential anti-inflammatory drugs, curcumin, apigenin, and tenilsetam, as candidate drugs, which could be tested in this model.
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8
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Matsuda T, Kondo A, Tsunashima Y, Togari A. Inhibitory Effect of Vitamin K2 on Interleukin-1.BETA.-Stimulated Proliferation of Human Osteoblasts. Biol Pharm Bull 2010; 33:804-8. [DOI: 10.1248/bpb.33.804] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Tomohiro Matsuda
- Department of Pharmacology, School of Dentistry, Aichi-Gakuin University
| | - Ayami Kondo
- Department of Pharmacology, School of Dentistry, Aichi-Gakuin University
| | | | - Akifumi Togari
- Department of Pharmacology, School of Dentistry, Aichi-Gakuin University
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9
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Ling H, Jia X, Zhang Y, Gapter LA, Lim YS, Agarwal R, Ng KY. Pachymic acid inhibits cell growth and modulates arachidonic acid metabolism in nonsmall cell lung cancer A549 cells. Mol Carcinog 2009; 49:271-82. [PMID: 19918789 DOI: 10.1002/mc.20597] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Hui Ling
- Department of Pharmacy, National University of Singapore, Singapore, Republic of Singapore
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10
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Matsuzawa Y, Kiuchi Y, Toyomura K, Matsumoto I, Nakamura H, Fujino H, Murayama T, Kawashima T. Activation of Cytosolic Phospholipase A2α by Epidermal Growth Factor (EGF) and Phorbol Ester in HeLa Cells: Different Effects of Inhibitors for EGF Receptor, Protein Kinase C, Src, and C-Raf. J Pharmacol Sci 2009; 111:182-92. [DOI: 10.1254/jphs.09201fp] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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11
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Hooks SB, Cummings BS. Role of Ca2+-independent phospholipase A2 in cell growth and signaling. Biochem Pharmacol 2008; 76:1059-67. [PMID: 18775417 DOI: 10.1016/j.bcp.2008.07.044] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 07/15/2008] [Accepted: 07/15/2008] [Indexed: 01/25/2023]
Abstract
Phospholipase A(2) (PLA(2)) are esterases that cleave glycerophospholipids to release fatty acids and lysophospholipids. Several studies demonstrate that PLA(2) regulate growth and signaling in several cell types. However, few of these studies have focused on Ca2+-independent phospholipase A(2) (iPLA(2) or Group VI PLA(2)). This class of PLA(2) was originally suggested to mediate phospholipid remodeling in several cell types including macrophages. As such, it was labeled as a housekeeping protein and thought not to play as significant of roles in cell growth as its older counterparts cytosolic PLA(2) (cPLA(2) or Group IV PLA(2)) and secretory PLA(2) (sPLA(2) or Groups I-III, V and IX-XIV PLA(2)). However, several recent studies demonstrate that iPLA(2) mediate cell growth, and do so by participating in signal transduction pathways that include epidermal growth factor receptors (EGFR), mitogen activated protein kinases (MAPK), mdm2, and even the tumor suppressor protein p53 and the cell cycle regulator p21. The exact mechanism by which iPLA(2) mediates these pathways are not known, but likely involve the generation of lipid signals such as arachidonic acid, lysophosphatidic acid (LPA) and lysophosphocholines (LPC). This review discusses the role of iPLA(2) in cell growth with special emphasis placed on their role in cell signaling. The putative lipid signals involved are also discussed.
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Affiliation(s)
- Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602, USA
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12
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Umannová L, Neča J, Andrysík Z, Vondráček J, Upham B, Trosko J, Hofmanová J, Kozubík A, Machala M. Non-dioxin-like polychlorinated biphenyls induce a release of arachidonic acid in liver epithelial cells: a partial role of cytosolic phospholipase A(2) and extracellular signal-regulated kinases 1/2 signalling. Toxicology 2008; 247:55-60. [PMID: 18367304 PMCID: PMC2577785 DOI: 10.1016/j.tox.2008.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 02/06/2008] [Accepted: 02/06/2008] [Indexed: 01/07/2023]
Abstract
Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) have been shown to act as tumor promoters in liver; however, the exact mechanisms of their action are still only partially understood. One of the interesting effects of NDL-PCBs is the acute inhibition of gap junctional intercellular communication (GJIC), an effect, which has been often found to be associated with tumor promotion. As previous studies have suggested that NDL-PCB-induced disruption of lipid signalling pathways might correspond with GJIC inhibition, we investigated effects of PCBs on the release of arachidonic acid (AA) in the rat liver epithelial WB-F344 cell line, a well-established model of liver progenitor cells. We found that both 2,2',4,4'-tetrachlorobiphenyl (PCB 47) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153), but not the dioxin-like, non-ortho-substituted, 3,3',4,4',5-pentachlorobiphenyl (PCB 126), induce a massive release of AA. The AA release, induced by PCB 153, was partially inhibited by extracellular signal-regulated kinases 1/2 (ERK1/2) signalling inhibitor, U0126, and by cytosolic phospholipase A(2) (cPLA(2)) inhibitor, AACOCF(3). Although PCB 153 induced both ERK1/2 and p38 activation, the specific p38 kinase inhibitor, SB203580, had no effect on AA release. Inhibitors of other phospholipases, including phosphatidylcholine-specific phospholipase C or phosphatidylinositol-specific phospholipase C, were also without effect. Taken together, our findings suggest that the AA release, induced by non-dioxin-like PCBs in liver progenitor cell line, is partially mediated by cytosolic PLA(2) and regulated by ERK1/2 kinases. Our results suggest that more attention should be paid to cell signalling pathways regulated by AA or eicosanoids after PCB exposure, which might be involved in their toxic effects.
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Affiliation(s)
- L. Umannová
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - J. Neča
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Z. Andrysík
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
| | - J. Vondráček
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - B.L. Upham
- National Food Safety & Toxicology Center, Michigan State University, East Lansing MI 48824, USA
| | - J.E. Trosko
- National Food Safety & Toxicology Center, Michigan State University, East Lansing MI 48824, USA
| | - J. Hofmanová
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
| | - A. Kozubík
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
| | - M. Machala
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
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13
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Babenko NA, Shakhova EG. Effects of flavonoids on sphingolipid turnover in the toxin-damaged liver and liver cells. Lipids Health Dis 2008; 7:1. [PMID: 18226198 PMCID: PMC2265705 DOI: 10.1186/1476-511x-7-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Accepted: 01/28/2008] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The ceramide generation is an early event in the apoptotic response to numerous stimuli including the oxidative stress and ceramide analogs mimic the stress effect and induce apoptosis. Flavonoids of German chamomile are reported to exhibit the hepatoprotective effect. Flavonoids affect sphingolipid metabolism and reduce the elevated ceramide level in the aged liver. In the present paper, the ceramide content and production in the CCl4- and ethanol-treated liver and hepatocytes as well as the correction of sphingolipid metabolism in the damaged liver using the mixture of German chamomile flavonoids (chamiloflan) or apigenin-7-glucoside (AP7Glu) have been investigated. RESULTS The experiments were performed in either the rat liver or hepatocytes of normal, CCl4- and ethanol-treated or flavonoid- and toxin plus flavonoid-treated animals. [14C]palmitic acid and [methyl-14C-phosphorylcholine]sphingomyelin were used to investigate the sphingolipid turnover. Addition of the CCl4 or ethanol to isolated hepatocyte suspensions caused loss of cell viability and increased the lactate dehydrogenase release from the cells into supernatant and ceramide level in the cells. CCl4 administration to the rats enlarged ceramide mass as well as neutral sphingomyelinase (SMase) activity and reduced ceramide degradation by the neutral ceramidase. Pretreatment of isolated hepatocytes with flavonoids abrogated the CCl4 effects on the cell membrane integrity and normalized the ceramide content. Flavonoid administration to the rats normalized the elevated ceramide content in the damaged liver via neutral SMase inhibition and ceramidase activation. CONCLUSION The data obtained have demonstrated that flavonoids affect sphingolipid metabolism in the CCl4- and ethanol-damaged liver and liver cells. Flavonoids normalized activities of key enzymes of sphingolipid turnover (neutral SMase and ceramidase) and ceramide contents in the damaged liver and liver cells, and stabilized the hepatocyte membranes.
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Affiliation(s)
- Nataliya A Babenko
- Department of Physiology of Ontogenesis, Institute of Biology, Kharkov Karazin National University, 4, Svobody pl., Kharkov, 61077, Ukraine
| | - Elena G Shakhova
- Department of Physiology of Ontogenesis, Institute of Biology, Kharkov Karazin National University, 4, Svobody pl., Kharkov, 61077, Ukraine
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14
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Choi SI, Jeong CS, Cho SY, Lee YS. Mechanism of apoptosis induced by apigenin in HepG2 human hepatoma cells: involvement of reactive oxygen species generated by NADPH oxidase. Arch Pharm Res 2007; 30:1328-35. [PMID: 18038912 DOI: 10.1007/bf02980274] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Although plant-derived flavonoids have been reported to have anti-cancer activities, the exact mechanism of these actions is not completely understood. In this study we investigated the role for reactive oxygen species (ROS) as a mediator of the apoptosis induced by apigenin, a widespread flavonoid in plant, in HepG2 human hepatoma cells. Apigenin reduced cell viability, and induced apoptotic cell death in a dose-dependent manner. In addition, it evoked a dose-related elevation of intracellular ROS level. Treatment with various inhibitors of the NADPH oxidase (diphenylene iodonium, apocynin, neopterine) significantly blunted both the generation of ROS and induction of apoptosis induced by apigenin. These results suggest that ROS generated through the activation of the NADPH oxidase may play an essential role in the apoptosis induced by apigenin in HepG2 cells. These results further suggest that apigenin may be valuable for the therapeutic management of human hepatomas.
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Affiliation(s)
- Soo Im Choi
- Plant Resources Research Institute, Duksung Women's University, Seoul 132-714, Korea
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15
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Saleh SM, Mann TS, Peters T, Betts RJ, Henry PJ. Influence of dexamethasone on protease-activated receptor 2-mediated responses in the airways. J Pharmacol Exp Ther 2007; 324:622-30. [PMID: 18003863 DOI: 10.1124/jpet.107.132753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stimulants of protease-activated receptor (PAR)(2) promote the generation of the bronchoprotective prostanoid prostaglandin (PG) E(2) by airway epithelial cells. In contrast, glucocorticoids reduce the levels of PGE(2) in airway epithelial cell cultures by concomitantly inhibiting pathways required for PGE(2) synthesis and facilitating pathways involved in PGE(2) inactivation. The aim of this study was to determine whether glucocorticoids inhibited PAR(2)-mediated, PGE(2)-dependent responses in epithelial cell cultures, in intact airway preparations, and in whole animals. In cultures of A549 cells, a PAR(2)-activating peptide SLI-GRL-NH(2) produced concentration and time-dependent increases in PGE(2) levels, which were significantly enhanced after exposure to lipopolysaccharide (LPS). However, SLIGRL-NH(2)-induced increases in PGE(2) levels were abolished by pretreatment of cells with the glucocorticoid, dexamethasone. In mouse isolated tracheal preparations, SLIGRL-NH(2) and PGE(2) induced concentration-dependent relaxation responses that were unaffected by dexamethasone, irrespective of whether dexamethasone exposure occurred in vitro or in vivo. Intranasal administration of LPS produced a pronounced increase in the numbers of neutrophils recovered from the bronchoalveolar lavage fluid of BALB/c mice. Numbers of recovered neutrophils were 40 to 60% lower in mice that received f-LIGRL-NH(2) (PAR(2)-activating peptide, 30 microg intranasally), PGE(2) (10 mugintranasally), or dexamethasone (1 mg/kg i.p.). In the combined presence of dexamethasone and f-LIGRL-NH(2) or dexamethasone and PGE(2), the number of neutrophils was suppressed further (80-83% lower). Thus, although dexamethasone abolished PAR(2)-mediated generation of PGE(2) in A549 cells, neither the smooth muscle relaxant nor the anti-inflammatory effects of PAR(2)-activating peptides (and PGE(2)) were diminished by in vitro or in vivo exposure to dexamethasone.
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Affiliation(s)
- Sham Mohd Saleh
- School of Medicine and Pharmacology, University of Western Australia, Stirling Highway, Nedlands, Australia
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16
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Herbert SP, Walker JH. Group VIA Calcium-independent Phospholipase A2 Mediates Endothelial Cell S Phase Progression. J Biol Chem 2006; 281:35709-16. [PMID: 16966332 DOI: 10.1074/jbc.m600699200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Arachidonic acid and its metabolites have been previously implicated in the regulation of endothelial cell proliferation. Arachidonic acid may be liberated from cellular phospholipids by the action of group VIA calcium-independent phospholipase A2 (iPLA2-VIA). Consequently, we tested the hypothesis that iPLA2-VIA activity is linked to the regulation of endothelial cell proliferation. Inhibition of iPLA2 activity by bromoenol lactone (BEL) was sufficient to entirely block endothelial cell growth. BEL dose-dependently inhibited endothelial cell DNA synthesis in a manner that was reversed upon the exogenous addition of arachidonic acid. DNA synthesis was inhibited by the S-isomer and not by the R-isomer of BEL, demonstrating that endothelial cell proliferation is mediated specifically by iPLA2-VIA. iPLA2-VIA activity was critical to the progression of endothelial cells through S phase and is required for the expression of the cyclin A/cdk2 complex. Thus, inhibition of iPLA2-VIA blocks S phase progression and results in exit from the cell cycle. Inhibition of iPLA2-VIA-mediated endothelial cell proliferation is sufficient to block angiogenic tubule formation in co-culture assays. Consequently, iPLA2-VIA is a novel regulator of endothelial cell S phase progression, cell cycle residence, and angiogenesis.
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Affiliation(s)
- Shane P Herbert
- Faculty of Biological Sciences, Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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17
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Saavedra G, Zhang W, Peterson B, Cummings BS. Differential Roles for Cytosolic and Microsomal Ca2+-Independent Phospholipase A2in Cell Growth and Maintenance of Phospholipids. J Pharmacol Exp Ther 2006; 318:1211-9. [PMID: 16763094 DOI: 10.1124/jpet.106.105650] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Physiological roles of microsomal (iPLA(2)gamma) and cytosolic (iPLA(2)beta)Ca(2+)-independent phospholipase A(2) were determined in two different epithelial cell models. R- and S-enantiomers of the iPLA(2) inhibitor bromoenol lactone (BEL) were isolated and shown to selectively inhibit iPLA(2gamma) and iPLA(2beta), respectively. The effect of these enantiomers on cell growth was assessed in human embryonic kidney 293 and Caki-1 cells using 3-(4-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT). S-BEL (0-5.0 microM) decreased MTT staining 35% after 24 h compared with control cells, whereas treatment with either R-BEL or R/S-BEL induced 15% decreases. Neither R-BEL nor S-BEL induced cell death as determined by annexin V and propidium iodide staining. Transfection of cells with iPLA(2)beta siRNA reduced MTT staining approximately 35%, whereas transfection of cells with iPLA(2)gamma siRNA only decreased MTT staining 10 to 15% compared with control cells. The effect of iPLA(2)beta and iPLA(2)gamma siRNA on cell number and protein was also determined, and iPLA(2)beta siRNA decreased cell number and protein 25% compared with control cells. In contrast, iPLA(2)gamma siRNA decreased cell number, but not cellular protein, compared with control cells. Selective inhibition of iPLA(2)beta, but not iPLA(2)gamma, decreased several arachidonic acid-containing phospholipids, including 16:1-20:4, 16:0-20:4, 18:1-20:4, and 18:0-20:4 phosphatidylcholine, showing that the ability of iPLA(2)beta inhibitors to decrease cell growth correlates with their ability to decrease arachidonic acid-containing phospholipids. These data show that iPLA(2)beta inhibition results in greater decreases in cell growth and proliferation than iPLA(2)gamma, identifies specific phospholipids whose expressions are differentially regulated by iPLA(2)beta and iPLA(2)gamma, and suggests novel roles for iPLA(2)beta in cell growth.
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Affiliation(s)
- Geraldine Saavedra
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, USA
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18
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Duan W, Zhang L. Cyclooxygenase inhibitors not inhibit resting lung cancer A549 cell proliferation. Prostaglandins Leukot Essent Fatty Acids 2006; 74:317-21. [PMID: 16618538 DOI: 10.1016/j.plefa.2006.02.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Accepted: 02/28/2006] [Indexed: 01/09/2023]
Abstract
Cyclooxygenase (COX) inhibitors were regarded as anticarcinogenic agents for lung cancer at least partly via PGE2; but these were based on cytokin stimulation experiment on A549 cell. In order to clarify whether COX inhibitors directly inhibit A549 cell, three COX inhibitors, NS398 (selective COX-2 inhibitor), SC560 (selective COX-1 inhibitor), and acetyl salicylic acid (ASA, non-selective COX inhibitor), were studied. NS398, and ASA, can inhibit PGE2 generation via COX-2 inhibition. The viability of A549 cell was assayed by MTT. However, without cytokin stimulation, all the three inhibitors (NS398 0.2-20 microM; SC560 1.0-100 nM; ASA 0.01-1.0 mM) were not able to inhibit A549 cell proliferation, in the other way round, NS398 promoted cell growth. And arachidonic acid (AA) and lipopolysaccharide (LPS) did not disturb the property of its growth. These data suggested that without cytokin stimulation, COX and PGE2 may not be the kernel molecules involved in A549 cell proliferation, and COX inhibitors could not inhibit A549 cell growth directly.
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Affiliation(s)
- Weigang Duan
- Jiangsu Center for Drug screening, China Pharmaceutical University, 1, Shennong Road, Nanjing 210038, PR China
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19
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Henry PJ. The protease-activated receptor2 (PAR2)-prostaglandin E2-prostanoid EP receptor axis: a potential bronchoprotective unit in the respiratory tract? Eur J Pharmacol 2006; 533:156-70. [PMID: 16483565 DOI: 10.1016/j.ejphar.2005.12.051] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2005] [Indexed: 01/12/2023]
Abstract
Protease-activated receptor2 (PAR2) is a subtype of G protein-coupled receptor that is widely expressed within the respiratory tract. Stimulation of PAR2 by proteases such as trypsin and tryptase, or by small peptidic activators induces a complex array of effects within the airways. One such PAR2-mediated effect by basal airway epithelial cells is the generation of prostaglandin E2. Prostaglandin E2 produces a raft of anti-inflammatory effects within the airways, principally through the activation of the prostanoid EP2 and EP3 receptor subtypes. This article reviews the PAR2-prostaglandin E2-prostanoid EP receptor axis and discusses approaches through which its activation may provide beneficial effects in respiratory disease.
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MESH Headings
- Animals
- Anti-Inflammatory Agents/pharmacology
- Anti-Inflammatory Agents/therapeutic use
- Dinoprostone/metabolism
- Disease Models, Animal
- Humans
- Ligands
- Pneumonia/metabolism
- Pneumonia/prevention & control
- Receptor, PAR-2/drug effects
- Receptor, PAR-2/metabolism
- Receptors, Prostaglandin E/drug effects
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E, EP1 Subtype
- Receptors, Prostaglandin E, EP2 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Respiratory Mucosa/drug effects
- Respiratory Mucosa/metabolism
- Respiratory System/drug effects
- Respiratory System/metabolism
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Affiliation(s)
- Peter J Henry
- School of Medicine and Pharmacology, University of Western Australia, Stirling Highway, Nedlands, Western Australia, 6009, Australia.
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20
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Knowles HJ, te Poele RH, Te Poole R, Workman P, Harris AL. Niacin induces PPARgamma expression and transcriptional activation in macrophages via HM74 and HM74a-mediated induction of prostaglandin synthesis pathways. Biochem Pharmacol 2006; 71:646-56. [PMID: 16386710 DOI: 10.1016/j.bcp.2005.11.019] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 11/21/2005] [Accepted: 11/22/2005] [Indexed: 01/11/2023]
Abstract
HM74 and HM74a have been identified as receptors for niacin. HM74a mediates the pharmacological anti-lipolytic effects of niacin in adipocytes by reducing intracellular cyclic AMP (cAMP) and inhibiting release of free fatty acids into the circulation. In macrophages, niacin induces peroxisome proliferator-activated receptor gamma (PPARgamma)-dependent and cAMP-dependent expression of genes mediating reverse cholesterol transport, although via an unidentified receptor. We describe constitutive expression of HM74a mRNA and hypoxia- and IFNgamma-inducible expression of HM74 and HM74a in human monocytic cell lines and primary cells in culture. In U937 cells niacin-induced expression of 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), the most potent endogenous ligand of PPARgamma. Both niacin and the structurally distinct HM74/HM74a ligand acifran-induced nuclear expression of PPARgamma protein and enhanced PPARgamma transcriptional activity. Niacin-induced PPARgamma transcriptional activity was pertussis toxin sensitive and required activity of phospholipase A(2) (EC 3.1.1.4), cyclo-oxygenase (EC 1.14.99.1) and prostaglandin D(2) synthase (EC 5.3.99.2). Niacin also induced PPARgamma transcriptional activity in HM74 and HM74a CHO cell transfectants, although not in vector-only control cells. This was sensitive to pertussis toxin and to inhibition of phoshoplipase A(2) and cyclo-oxygenase activity. Additionally, niacin increased intracellular cAMP in U937 via a pertussis toxin and cyclo-oxygenase-sensitive mechanism. These results indicate that HM74 and HM74a can mediate macrophage responses to niacin via activation of the prostaglandin synthesis pathway and induction and activation of PPARgamma. This suggests a novel mechanism(s) mediating the clinical effects of pharmacological doses of niacin.
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Affiliation(s)
- Helen J Knowles
- Cancer Research UK Molecular Oncology Laboratory, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, UK
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21
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Kawabata A, Kubo S, Ishiki T, Kawao N, Sekiguchi F, Kuroda R, Hollenberg MD, Kanke T, Saito N. Proteinase-activated receptor-2-mediated relaxation in mouse tracheal and bronchial smooth muscle: signal transduction mechanisms and distinct agonist sensitivity. J Pharmacol Exp Ther 2004; 311:402-10. [PMID: 15199093 DOI: 10.1124/jpet.104.068387] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We characterized the tracheal and bronchial relaxation caused by proteinase-activated receptor-2 (PAR-2) activation in ddY mice and/or in wild-type and PAR-2-knockout mice of C57BL/6 background. Ser-Leu-Ile-Gly-Arg-Leu-amide (SLIGRL-NH(2)) and Thr-Phe-Leu-Leu-Arg-amide, PAR-2- and PAR-1-activating peptides, respectively, caused relaxation in the isolated ddY mouse trachea and main bronchus. The relaxation was abolished by specific inhibitors of cyclooxygenase (COX)-1, COX-2, mitogen-activated protein kinase kinase (MEK), and p38 MAP kinase. The MEK and p38 MAP kinase inhibitors did not affect prostaglandin E(2)-induced relaxation. Inhibitors of cytosolic Ca(2+)-dependent phospholipase A(2) (PLA), Ca(2+)-independent PLA(2), diacylglycerol lipase, tyrosine kinase, and protein kinase C exhibited no or only minor inhibitory effects on the PAR-mediated relaxation. Trypsin, a PAR-2 activator, and 2-furoyl-Leu-Ile-Gly-Arg-Leu-amide, a potent PAR-2-activating peptide, in addition to SLIGRL-NH(2), caused airway relaxation in wild-type C57BL/6 mice, as in ddY mice. In PAR-2-knockout mice, the peptide effects were absent and the potency of trypsin decreased. Desensitization of PAR-2 and/or PAR-1 greatly suppressed the relaxant effect of trypsin. The bronchial and tracheal tissues displayed distinct sensitivities toward trypsin and the PAR-2-activating peptides. Our data indicate an involvement of both COX-1 and COX-2, and the MEK-extracellular signal-regulated kinase and p38 MAP kinase signaling pathways in the PAR-2- and PAR-1-triggered relaxation of mouse airway tissue, and substantiate a role for PAR-2 in regulating both the trachea and bronchial responsiveness in the mouse lung.
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Affiliation(s)
- Atsufumi Kawabata
- Division of Physiology and Pathophysiology, School of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan.
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22
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Gilroy DW, Newson J, Sawmynaden P, Willoughby DA, Croxtall JD. A novel role for phospholipase A2 isoforms in the checkpoint control of acute inflammation. FASEB J 2004; 18:489-98. [PMID: 15003994 DOI: 10.1096/fj.03-0837com] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Acute inflammation can be considered in terms of a series of checkpoints where each phase of cellular influx, persistence, and clearance is controlled by endogenous stop and go signals. It is becoming increasingly apparent that in addition to initiating the inflammatory response, eicosanoids may also mediate resolution. This suggests there are two phases of arachidonic acid release: one at onset for the generation of proinflammatory eicosanoids and one at resolution for the synthesis of proresolving eicosanoids. What is unclear is the identity of the phospholipase (PLA2) isoforms involved in this biphasic release of arachidonic acid. We show here that type VI iPLA2 drives the onset of acute pleurisy through the synthesis of PGE2, LTB4, PAF, and IL-1beta. However, during resolution there is a switch to a sequential induction of first sPLA2 (types IIa and V) that mediates the release of PAF and lipoxin A4, which, in turn, are responsible for the subsequent induction of type IV cPLA2 that mediates the release of arachidonic acid for the synthesis of proresolving prostaglandins. This study is the first of its kind to address the respective roles of PLA2 isoforms in acute resolving inflammation and to identify type VI iPLA2 as a potentially selective target for the treatment of inflammatory diseases.
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Affiliation(s)
- Derek W Gilroy
- Department of Experimental Pathology, William Harvey Research Institute, St. Bartholomew's & The Royal London School of Medicine and Dentistry, London.
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23
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Jae Han H, Yeong Park J, Jung Lee Y, Taub M. Epidermal growth factor inhibits14C-?-methyl-d-glucopyranoside uptake in renal proximal tubule cells: Involvement of PLC/PKC, p44/42 MAPK, and cPLA2. J Cell Physiol 2004; 199:206-16. [PMID: 15040003 DOI: 10.1002/jcp.10438] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The effect of EGF on (14)C-alpha-methyl-D-glucopyranoside (alpha-MG) uptake and its related signaling pathways were examined in primary cultured rabbit renal proximal tubule cells (PTCs). Epidermal growth factor (EGF) (50 ng/ml) was found to inhibit alpha-MG uptake, a distinctive proximal tubule marker. The EGF effect was blocked by AG1478 (an EGF receptor antagonist) or genistein and herbimycin (tyrosine kinase inhibitors), respectively. In addition, the EGF-induced inhibition of alpha-MG uptake was blocked by neomycin and U73122 (phospholipase C inhibitors) as well as staurosporine, H-7, and bisindolylmaleimide I (protein kinase C inhibitors). EGF was also observed to increase inositol phosphate formation. Furthermore, both the EGF-induced inhibition of alpha-MG uptake and increase of arachidonic acid (AA) release were blocked by AACOCF(3) (a cytosolic phospholipase A(2) inhibitor), indomethacin (a cyclooxygenase inhibitor), and econazole (a cytochrome P-450 epoxygenase inhibitor). We examined the involvement of mitogen-activated protein kinases (MAPKs) in mediating the effect of EGF on alpha-MG uptake. Indeed, EGF increased phosphorylation of p44/p42 MAPK and the EGF-induced inhibition of alpha-MG uptake as well as the stimulatory effect of EGF on AA release was blocked by PD 98059 (a p44/42 MAPK inhibitor), suggesting a causal relationship. However, inhibitors of PKC also prevented the EGF-induced increase of AA release. In conclusion, EGF partially inhibited alpha-MG uptake via PLC/PKC, p44/42 MAPK, and PLA(2) signaling pathways.
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Affiliation(s)
- Ho Jae Han
- Department of Veterinary Physiology, College of Veterinary Medicine, Hormone Research Center, Chonnam National University, Gwangju, Korea.
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24
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Sweeney FJ, Wachtmann TS, Eskra JD, Verdries KA, Lambalot RH, Carty TJ, Perez JR, Audoly LP. Inhibition of IL-1beta-dependent prostaglandin E2 release by antisense microsomal prostaglandin E synthase 1 oligonucleotides in A549 cells. Mol Cell Endocrinol 2003; 205:151-7. [PMID: 12890577 DOI: 10.1016/s0303-7207(03)00091-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The metabolism of arachidonic acid through the cyclooxygenase pathway is a highly regulated cellular process that results in the formation of PGH2. This unstable intermediate can be enzymatically metabolized to PGE2 by the actions of a microsomal 17 kDa PGE synthase (mPGES1). Treatment of A549 cells with IL-1beta for 24 h resulted in a twofold increase in mPGES1 mRNA, protein expression, and PGES specific activity. To understand the relationship between expression of mPGES1 and PGE2 formation, IL-1beta treated cells were incubated with increasing concentrations of antisense oligonucleotides (ASO) and their effects compared to cells treated with reverse sense oligonucleotides (RSO) designed against the ATG translation initiation codon of mPGES1. Incubation with ASO resulted in a 44% reduction in mRNA expression level as compared to RSO-treated cells. Microsomal preparations isolated from ASO- and RSO-treated cells were analyzed for their ability to convert PGH2 to PGE2 in the presence 2.5 mM reduced glutathione. An approximate 50% reduction (ASO: 1.8 nmol/min/mg, RSO: 3.7 nmol/min/mg) in PGES activity, protein expression by immunodetection, and extracellular PGE2 release was detected in these samples. As a control in these studies, the protein levels of COX2 and secreted IL-8 were quantified; no change in these levels was observed. These results demonstrate the direct association between mPGES1 expression, its enzymatic activity, and total PGE2 production following an inflammatory stimulus.
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Affiliation(s)
- Francis J Sweeney
- Department of Inflammation, Pfizer Global Research and Development, Eastern Point Road, Groton, CT 06340, USA
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25
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Grewal S, Ponnambalam S, Walker JH. Association of cPLA2-alpha and COX-1 with the Golgi apparatus of A549 human lung epithelial cells. J Cell Sci 2003; 116:2303-10. [PMID: 12711701 DOI: 10.1242/jcs.00446] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cytosolic phospholipase A2-alpha (cPLA2-alpha) is an 85 kDa, Ca2+-sensitive enzyme involved in receptor-mediated prostaglandin synthesis. In airway epithelial cells, the release of prostaglandins is crucial in regulating the inflammatory response. Although prostaglandin release has been studied in various epithelial cell models, the subcellular location of cPLA2-alpha in these cells is unknown. Using high-resolution confocal microscopy of the human A549 lung epithelial cell line, we show that cPLA2-alpha relocates from the cytosol and nuclei to a juxtanuclear region following stimulation with the Ca2+ ionophore A23187. Double staining with rhodamine-conjugated wheat germ agglutinin confirmed this region to be the Golgi apparatus. Markers specific for Golgi subcompartments revealed that cPLA2-alpha is predominantly located at the trans-Golgi stack and the trans-Golgi network following elevation of cytosolic Ca2+. Furthermore, treatment of cells with the Golgi-disrupting agent brefeldin A caused a redistribution of cPLA2-alpha, confirming that cPLA2-alpha associates with Golgi-derived membranes. Finally, a specific co-localization of cPLA2-alpha with cyclooxygenase-1 but not cyclooxygenase-2 was evident at the Golgi apparatus. These results, combined with recent data on the role of PLA2 activity in maintaining Golgi structure and function, suggest that Golgi localization of cPLA2-alpha may be involved in membrane trafficking in epithelial cells.
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Affiliation(s)
- Seema Grewal
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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26
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Lindenmeyer F, Li H, Menashi S, Soria C, Lu H. Apigenin acts on the tumor cell invasion process and regulates protease production. Nutr Cancer 2002; 39:139-47. [PMID: 11588896 DOI: 10.1207/s15327914nc391_19] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Apigenin is a widely distributed plant flavonoid and was proposed as an antitumor agent. In this study, we investigated the apigenin effects on the protease-mediated invasiveness in an estrogen-insensitive breast tumor cell line MDA-MB231. The results show that apigenin at 22.8-45.5 microM (2.5-10 micrograms/ml) strongly inhibited, in a dose-dependent manner, tumor cell invasion through Matrigel, cell migration, and cell proliferation. We show that apigenin treatment from 22.8 microM (2.5 micrograms/ml) led to a partial decrease in urokinase-plasminogen activator expression and to a total inhibition of phorbol 12-myristate 13-acetate-induced matrix metalloproteinase-9 secretion. We also demonstrate in the apigenin-treated cells a defective adhesion to Matrigel and a G2-M cell cycle arrest. Taken together, our results demonstrate that apigenin is a pleiotropic effector affecting protease-dependent invasiveness and associated processes and proliferation of tumor cells.
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Affiliation(s)
- F Lindenmeyer
- Institut National de la Santé et de la Recherche Médicale, U553, Bât. INSERM, Institut d'Hématologie, Hôpital Saint-Louis, Université Paris 7, 75475 Paris, France
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27
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Croxtall JD, van Hal PTW, Choudhury Q, Gilroy DW, Flower RJ. Different glucocorticoids vary in their genomic and non-genomic mechanism of action in A549 cells. Br J Pharmacol 2002; 135:511-9. [PMID: 11815387 PMCID: PMC1573139 DOI: 10.1038/sj.bjp.0704474] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2001] [Revised: 10/30/2001] [Accepted: 10/31/2001] [Indexed: 12/26/2022] Open
Abstract
We have examined the effects of 12 glucocorticoids as inhibitors of A549 cell growth. Other than cortisone and prednisone, all the glucocorticoids inhibited cell growth and this was strongly correlated (r=0.91) with inhibition of prostaglandin (PG)E(2) formation. The molecular mechanism by which the active steroids prevented PGE(2) synthesis was examined and three groups were identified. Group A drugs did not inhibit arachidonic acid release but inhibited the induction of COX2. Group B drugs were not able to inhibit the induction of COX2 but inhibited arachidonic acid release through suppression of cPLA(2) activation. Group C drugs were apparently able to bring about both effects. The inhibitory actions of all steroids was dependent upon glucocorticoid receptor occupation since RU486 reversed their effects. However, group A acted through the NF-kappaB pathway to inhibit COX2 as the response was blocked by the inhibitor geldanamycin which prevents dissociation of GR and the effect was blocked by APDC, the NF-kappaB inhibitor. On the other hand, the group B drugs were not inhibited by NF-kappaB inhibitors or geldanamycin but their effect was abolished by the src inhibitor PP2. Group C drugs depended on both pathways. In terms of PGE(2) generation, there is clear evidence of two entirely separate mechanisms of glucocorticoid action, one of which correlates with NF-kappaB mediated genomic actions whilst the other, depends upon rapid effects on a cell signalling system which does not require dissociation of GR. The implications for these findings are discussed.
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Affiliation(s)
- Jamie D Croxtall
- Department of Biochemical Pharmacology, The William Harvey Research Institute, St. Bartholomew's and the Royal London School of Medicine & Dentistry (Queen Mary and Westfield College), Charterhouse Square, London EC1M 6BQ.
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Humphries JE, Elizondo L, Yoshino TP. Protein kinase C regulation of cell spreading in the molluscan Biomphalaria glabrata embryonic (Bge) cell line. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1540:243-52. [PMID: 11583819 DOI: 10.1016/s0167-4889(01)00136-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cellular adhesion and spreading are critical components involved in the processes of cell and tissue development, and immune responses in molluscs, but at present, little is known regarding the signaling pathways involved in these basic cellular functions. In the present study, the molluscan Biomphalaria glabrata embryonic (Bge) cell line was used as an in vitro model to study the signal transduction pathways regulating molluscan cell adhesion and spreading behavior. Western blot analysis using antibodies specific to mitogen-activated protein kinase (MAPK) revealed the presence of an MAPK-like immunoreactive protein in Bge cells, that was phosphorylated upon exposure to phorbol myristate acetate (PMA). Moreover, Bge cell treatment with inhibitors of protein kinase C (PKC), Ras and MAPK kinase (Mek) suppressed PMA-induced expression of activated MAPK, suggesting that PKC-, Ras- and Mek-like molecules may be acting upstream of MAPK. Similarly, in vitro Bge cell-spreading assays were performed in conjunction with the same panel of inhibitors to determine the potential involvement of PKC, Ras and Mek in cellular adhesion/spreading. Results revealed a similar pattern of inhibition of cell-spreading behavior strongly implying that the Bge cell spreading also may be regulated through a MAPK-associated signal transduction pathway(s) involving proteins similar to PKC, Ras and Mek.
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Affiliation(s)
- J E Humphries
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, 53706, USA.
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