151
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Morelli A, Ferrari D, Bolognesi G, Rizzuto R, Virgilio FD. Proapoptotic plasma membrane pore: P2X7 receptor. Drug Dev Res 2001. [DOI: 10.1002/ddr.1160] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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152
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Braun N, Sévigny J, Robson SC, Enjyoji K, Guckelberger O, Hammer K, Di Virgilio F, Zimmermann H. Assignment of ecto-nucleoside triphosphate diphosphohydrolase-1/cd39 expression to microglia and vasculature of the brain. Eur J Neurosci 2000. [DOI: 10.1111/j.1460-9568.2000.01342.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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153
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Braun N, Sevigny J, Robson SC, Enjyoji K, Guckelberger O, Hammer K, Di Virgilio F, Zimmermann H. Assignment of ecto-nucleoside triphosphate diphosphohydrolase-1/cd39 expression to microglia and vasculature of the brain. Eur J Neurosci 2000. [DOI: 10.1046/j.1460-9568.2000.01342.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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154
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Hide I, Tanaka M, Inoue A, Nakajima K, Kohsaka S, Inoue K, Nakata Y. Extracellular ATP triggers tumor necrosis factor-alpha release from rat microglia. J Neurochem 2000; 75:965-72. [PMID: 10936177 DOI: 10.1046/j.1471-4159.2000.0750965.x] [Citation(s) in RCA: 347] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Brain microglia are a major source of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), which have been implicated in the progression of neurodegenerative diseases. Recently, microglia were revealed to be highly responsive to ATP, which is released from nerve terminals, activated immune cells, or damaged cells. It is not clear, however, whether released ATP can regulate TNF-alpha secretion from microglia. Here we demonstrate that ATP potently stimulates TNF-alpha release, resulting from TNF-alpha mRNA expression in rat cultured brain microglia. The TNF-alpha release was maximally elicited by 1 mM ATP and also induced by a P2X(7) receptor-selective agonist, 2'- and 3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate, suggesting the involvement of P2X(7) receptor. ATP-induced TNF-alpha release was Ca(2+)-dependent, and a sustained Ca(2+) influx correlated with the TNF-alpha release in ATP-stimulated microglia. ATP-induced TNF-alpha release was inhibited by PD 098059, an inhibitor of extracellular signal-regulated protein kinase (ERK) kinase 1 (MEK1), which activates ERK, and also by SB 203580, an inhibitor of p38 mitogen-activated protein kinase. ATP rapidly activated both ERK and p38 even in the absence of extracellular Ca(2+). These results indicate that extracellular ATP triggers TNF-alpha release in rat microglia via a P2 receptor, likely to be the P2X(7) subtype, by a mechanism that is dependent on both the sustained Ca(2+) influx and ERK/p38 cascade, regulated independently of Ca(2+) influx.
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Affiliation(s)
- I Hide
- Department of Pharmacology, Institute of Pharmaceutical Sciences, Hiroshima University School of Medicine, Japan.
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155
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Liu JS, John GR, Sikora A, Lee SC, Brosnan CF. Modulation of interleukin-1beta and tumor necrosis factor alpha signaling by P2 purinergic receptors in human fetal astrocytes. J Neurosci 2000; 20:5292-9. [PMID: 10884313 PMCID: PMC6772323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
In human astrocytes, interleukin-1beta (IL-1beta) is a potent inducer of genes associated with inflammation. In this study, we tested the hypothesis that in primary cultures of human fetal astrocytes signaling by the P2 purinergic nucleotide receptor pathway contributes to, or modulates, cytokine-mediated signal transduction. Calcium imaging studies indicated that most cells in culture responded to ATP, whereas only a subpopulation responded to UTP. Pretreatment of astrocytes with P2 receptor antagonists, including suramin and periodate oxidized ATP (oATP), resulted in a significant downregulation of IL-1beta-stimulated expression of nitric oxide, tumor necrosis factor (TNFalpha), and IL-6 at both the protein and mRNA levels, without affecting cell viability. In cells transiently transfected with reporter constructs, IL-1beta demonstrated more potent activation of the transcription factors nuclear factor -kappaB (NF-kappaB) and activator protein-1 (AP-1) than TNFalpha. However, pretreatment with oATP downregulated activation of NF-kappaB and AP-1 by IL-1beta or TNFalpha. Electromobility shift assays using oligonucleotides containing specific NF-kappaB binding sequences confirmed that pretreatment with oATP or apyrase attenuated cytokine-mediated induction of this transcription factor. From these data, we conclude that P2 receptor-mediated signaling intersects with that of IL-1beta and TNFalpha to regulate responses to cytokines in the CNS. Because inflammation, trauma, and stress all lead to the release of high levels of extracellular nucleotides, such as ATP and UTP, signaling via P2 receptors may provide a mechanism whereby cells can sense and respond to events occurring in the extracellular environment and can fine tune the transcription of genes involved in the inflammatory response.
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Affiliation(s)
- J S Liu
- Departments of Pathology, Microbiology and Immunology, and Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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156
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Di Virgilio F. Dr. Jekyll/Mr. Hyde: the dual role of extracellular ATP. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 2000; 81:59-63. [PMID: 10869701 DOI: 10.1016/s0165-1838(00)00114-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- F Di Virgilio
- Department of Experimental and Diagnostic Medicine, Section of General Pathology and Biotechnology Center, University of Ferrara, Via Borsari 46, I-44100, Ferrara, Italy.
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157
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Neary JT. Trophic actions of extracellular ATP: gene expression profiling by DNA array analysis. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 2000; 81:200-4. [PMID: 10869721 DOI: 10.1016/s0165-1838(00)00154-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In addition to Professor Burnstock's work on the short-term signaling actions of extracellular nucleotides and nucleosides, Geoff has had a long-standing interest in trophic actions of purines in development and in pathophysiological conditions which has been instrumental in encouraging my work in this area. The trophic actions of extracellular ATP, alone or in combination with polypeptide growth factors, may play an important role in brain development and may contribute to the reactive gliosis that accompanies brain injury and neurodegeneration. P2Y receptors in astrocytes are coupled to the ERK/MAPK cascade, a signal transduction mechanism crucial for cellular proliferation and differentiation. The mitogenic signaling pathway from P2Y receptors to ERK involves phospholipase D and a calcium-independent PKC isoform, PKCdelta. DNA array analysis reveals a number of changes in gene expression after P2Y receptor occupancy, indicating that this methodology will be a powerful tool in understanding the mechanisms underlying the trophic actions of extracellular nucleotides and nucleosides.
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Affiliation(s)
- J T Neary
- Research Service, VA Medical Center, and Departments of Pathology and Biochemistry & Molecular Biology, University of Miami School of Medicine, Miami, FL 33125, USA.
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158
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Fam SR, Gallagher CJ, Salter MW. P2Y(1) purinoceptor-mediated Ca(2+) signaling and Ca(2+) wave propagation in dorsal spinal cord astrocytes. J Neurosci 2000; 20:2800-8. [PMID: 10751431 PMCID: PMC6772222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
ATP is known to act as an extracellular messenger mediating the propagation of Ca(2+) waves in astrocyte networks. ATP mediates Ca(2+) waves by activating P2Y purinoceptors, which mobilize intracellular Ca(2+) in astrocytes. A number of P2Y purinoceptor subtypes have been discovered, but it is not known which P2Y subtypes participate in transmitting astrocyte Ca(2+) waves. Here, we show that ATP analogs that are selective agonists for the P2Y(1) subtype of purinoceptor caused release of intracellular Ca(2+) in astrocytes from the dorsal spinal cord. The Ca(2+) responses were blocked by adenosine-3'-phospho-5'-phosphosulfate, an antagonist known to selectively inhibit P2Y(1) but not other P2Y purinoceptor subtypes. Also, we show that P2Y(1) mRNA is expressed in dorsal spinal cord astrocytes. Furthermore, expression of P2Y(1) in an astrocytoma cell line lacking endogenous purinoceptors was sufficient to permit propagation of intercellular Ca(2+) waves. Finally, Ca(2+) wave propagation in dorsal spinal cord astrocytes was suppressed by pharmacologically blocking P2Y(1) purinoceptors. Together, these results indicate that dorsal spinal astrocytes express functional P2Y(1) purinoceptors, which participate in the transmission of Ca(2+) waves. Ca(2+) waves in astrocytes have been implicated as a major signaling pathway coordinating glial and neuronal activity; therefore, P2Y(1) purinoceptors may represent an important link in cell-cell signaling in the CNS.
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Affiliation(s)
- S R Fam
- Programme in Brain and Behaviour, Hospital For Sick Children, University of Toronto, Toronto, Ontario M5G 1X8, Canada
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159
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Lenz G, Gottfried C, Luo Z, Avruch J, Rodnight R, Nie WJ, Kang Y, Neary JT. P(2Y) purinoceptor subtypes recruit different mek activators in astrocytes. Br J Pharmacol 2000; 129:927-36. [PMID: 10696092 PMCID: PMC1571921 DOI: 10.1038/sj.bjp.0703138] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/1999] [Revised: 12/03/1999] [Accepted: 12/07/1999] [Indexed: 11/09/2022] Open
Abstract
Extracellular ATP can function as a glial trophic factor as well as a neuronal transmitter. In astrocytes, mitogenic signalling by ATP is mediated by metabotropic P(2Y) receptors that are linked to the extracellular signal regulated protein kinase (Erk) cascade, but the types of P(2Y) receptors expressed in astrocytes have not been defined and it is not known whether all P(2Y) receptor subtypes are coupled to Erk by identical or distinct signalling pathways. We found that the P(2Y) receptor agonists ATP, ADP, UTP and 2-methylthioATP (2MeSATP) activated Erk and its upstream activator MAP/Erk kinase (Mek). cRaf-1, the first kinase in the Erk cascade, was activated by 2MeSATP, ADP and UTP but, surprisingly, cRaf-1 was not stimulated by ATP. Furthermore, ATP did not activate B-Raf, the major isoform of Raf in the brain, nor other Mek activators such as Mek kinase 1 (MekK1) and MekK2/3. Reverse transcriptase-polymerase chain reaction (RT - PCR) studies using primer pairs for cloned rat P(2Y) receptors revealed that rat cortical astrocytes express P(2Y(1)), a receptor subtype stimulated by ATP and ADP and their 2MeS analogues, as well as P(2Y(2)) and P(2Y(4)), subtypes in rats for which ATP and UTP are equipotent. Transcripts for P(2Y(6)), a pyrimidine-preferring receptor, were not detected. ATP did not increase cyclic AMP levels, suggesting that P(2Y(11)), an ATP-preferring receptor, is not expressed or is not linked to adenylyl cyclase in rat cortical astrocytes. These signal transduction and RT - PCR experiments reveal differences in the activation of cRaf-1 by P(2Y) receptor agonists that are inconsistent with properties of the P(2Y(1)), P(2Y(2)) and P(2Y(4)) receptors shown to be expressed in astrocytes, i.e. ATP=UTP; ATP=2MeSATP, ADP. This suggests that the properties of the native P(2Y) receptors coupled to the Erk cascade differ from the recombinant P(2Y) receptors or that astrocytes express novel purine-preferring and pyrimidine-preferring receptors coupled to the ERK cascade.
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Affiliation(s)
- Guido Lenz
- Department of Biophysics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Carmem Gottfried
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Zhijun Luo
- Diabetes Unit Medical Services, Massachusetts General Hospital, Boston, Massachusetts, U.S.A
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, U.S.A
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Joseph Avruch
- Diabetes Unit Medical Services, Massachusetts General Hospital, Boston, Massachusetts, U.S.A
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, U.S.A
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Richard Rodnight
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Wie-Jia Nie
- Research Service, Veterans Affairs Medical Center, Miami, Florida, U.S.A
| | - Yuan Kang
- Research Service, Veterans Affairs Medical Center, Miami, Florida, U.S.A
| | - Joseph T Neary
- Research Service, Veterans Affairs Medical Center, Miami, Florida, U.S.A
- Department of Pathology, University of Miami, School of Medicine, Miami, Florida, U.S.A
- Department of Biochemistry & Molecular Biology, University of Miami, School of Medicine, Miami, Florida, U.S.A
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160
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Pae HO, Yoo JC, Choi BM, Lee EJ, Song YS, Chung HT. 12-O-tetradecanoyl phorbol 13-acetate, protein kinase C (PKC) activator, protects human leukemia HL-60 cells from taxol-induced apoptosis: possible role for extracellular signal-regulated kinase. Immunopharmacol Immunotoxicol 2000; 22:61-73. [PMID: 10737257 DOI: 10.3109/08923970009016406] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The purpose of this study was to evaluate whether the mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) signaling pathway contributes to 12-O-tertadecanoyl phorbol 13-acetate (TPA)-mediated protection from taxol-induced apoptosis of human leukemia HL-60 cells. Treatment of cells with taxol for 12 h resulted in apoptosis of HL-60 cells. TPA was protective against taxol-induced apoptosis and this anti-apoptotic effect was reversible when TPA was used in conjunction with staurosporine and H-7, PKC inhibitors, suggesting that TPA may protect HL-60 cells against taxol-induced apoptosis via the PKC-dependent pathway. Since TPA stimulates MEK signal transduction pathway in HL-60 cells, we postulated that MEK pathway may be playing a role in the ability of TPA to inhibit taxol-induced apoptosis. PD098059, a specific MEK kinase inhibitor, abolished the ability of TPA to inhibit taxol-induced apoptosis. These results suggest that activation of PKC in HL-60 cells confers protection against taxol-induced apoptosis and that MEK mediates anti-apoptotic signaling of PKC.
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Affiliation(s)
- H O Pae
- Department of Microbiology and Immunology and Medicinal Resources Research Center of Wonkwang University, Iksan, Chonbug, Korea
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161
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Baricordi OR, Melchiorri L, Adinolfi E, Falzoni S, Chiozzi P, Buell G, Di Virgilio F. Increased proliferation rate of lymphoid cells transfected with the P2X(7) ATP receptor. J Biol Chem 1999; 274:33206-8. [PMID: 10559192 DOI: 10.1074/jbc.274.47.33206] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human leukocytes can express the P2X(7) purinergic receptor, an ionic channel gated by extracellular ATP, for which the physiological role is only partially understood. Transfection of P2X(7) cDNA into lymphoid cells that lack this receptor sustains their proliferation in serum-free medium. Increased proliferation of serum-starved P2X(7) transfectants is abolished by the P2X(7) receptor blocker oxidized ATP or by the ATP hydrolase apyrase. Both wild type and P2X(7)-transfected lymphoid cells release large amounts of ATP into the culture medium. These data suggest the operation of an ATP-based autocrine/paracrine loop that supports lymphoid cell growth in the absence of serum-derived growth factors.
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Affiliation(s)
- O R Baricordi
- Section of Medical Genetics, Department of Experimental Medicine, University of Ferrara, I-44100 Ferrara, Italy
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