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Nicolaou A, Mauro C, Urquhart P, Marelli-Berg F. Polyunsaturated Fatty Acid-derived lipid mediators and T cell function. Front Immunol 2014; 5:75. [PMID: 24611066 PMCID: PMC3933826 DOI: 10.3389/fimmu.2014.00075] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 02/11/2014] [Indexed: 01/10/2023] Open
Abstract
Fatty acids are involved in T cell biology both as nutrients important for energy production as well as signaling molecules. In particular, polyunsaturated fatty acids are known to exhibit a range of immunomodulatory properties that progress through T cell mediated events, although the molecular mechanisms of these actions have not yet been fully elucidated. Some of these immune activities are linked to polyunsaturated fatty acid-induced alteration of the composition of cellular membranes and the consequent changes in signaling pathways linked to membrane raft-associated proteins. However, significant aspects of the polyunsaturated fatty acid bioactivities are mediated through their transformation to specific lipid mediators, products of cyclooxygenase, lipoxygenase, or cytochrome P450 enzymatic reactions. Resulting bioactive metabolites including prostaglandins, leukotrienes, and endocannabinoids are produced by and/or act upon T leukocytes through cell surface receptors and have been shown to alter T cell activation and differentiation, proliferation, cytokine production, motility, and homing events. Detailed appreciation of the mode of action of these lipids presents opportunities for the design and development of therapeutic strategies aimed at regulating T cell function.
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Affiliation(s)
- Anna Nicolaou
- Manchester Pharmacy School, Faculty of Medical and Human Sciences, The University of Manchester , Manchester , UK
| | - Claudio Mauro
- Centre for Biochemical Pharmacology, William Harvey Research Institute, Queen Mary University of London , London , UK
| | - Paula Urquhart
- Manchester Pharmacy School, Faculty of Medical and Human Sciences, The University of Manchester , Manchester , UK
| | - Federica Marelli-Berg
- Centre for Biochemical Pharmacology, William Harvey Research Institute, Queen Mary University of London , London , UK
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Lone AM, Taskén K. Proinflammatory and immunoregulatory roles of eicosanoids in T cells. Front Immunol 2013; 4:130. [PMID: 23760108 PMCID: PMC3671288 DOI: 10.3389/fimmu.2013.00130] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 05/17/2013] [Indexed: 01/08/2023] Open
Abstract
Eicosanoids are inflammatory mediators primarily generated by hydrolysis of membrane phospholipids by phospholipase A2 to ω-3 and ω-6 C20 fatty acids that next are converted to leukotrienes (LTs), prostaglandins (PGs), prostacyclins (PCs), and thromboxanes (TXAs). The rate-limiting and tightly regulated lipoxygenases control synthesis of LTs while the equally well-controlled cyclooxygenases 1 and 2 generate prostanoids, including PGs, PCs, and TXAs. While many of the classical signs of inflammation such as redness, swelling, pain, and heat are caused by eicosanoid species with vasoactive, pyretic, and pain-inducing effects locally, some eicosanoids also regulate T cell functions. Here, we will review eicosanoid production in T cell subsets and the inflammatory and immunoregulatory functions of LTs, PGs, PCs, and TXAs in T cells.
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Affiliation(s)
- Anna Mari Lone
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo and Oslo University Hospital , Oslo , Norway ; Biotechnology Centre, University of Oslo , Oslo , Norway ; K.G. Jebsen Inflammation Research Centre, University of Oslo , Oslo , Norway
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Akhtar Khan N. Polyunsaturated fatty acids in the modulation of T-cell signalling. Prostaglandins Leukot Essent Fatty Acids 2010; 82:179-87. [PMID: 20189788 DOI: 10.1016/j.plefa.2010.02.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Indexed: 11/25/2022]
Abstract
n-3 polyunsaturated fatty acids (PUFA) have been shown to modulate immune responses. These agents, being considered as adjuvant immunosuppressants, have been used in the treatment of various inflammatory and autoimmune diseases. However, the molecular mechanisms of action of n-3 PUFA-induced immunosuppressive effects are not well-understood. Since exogenous n-3 PUFA, under in vitro and in vivo conditions, are efficiently incorporated into T-cell plasma membranes, a number of recent studies have demonstrated that these agents may modulate T-cell signalling. In this review, the interactions of n-3 PUFA with the second messenger cascade initiated during early and late events of T-cell activation are discussed. We particularly focus on how these fatty acids can modulate the production of diacylglycerol and the activation of protein kinase C, mitogen activated protein kinase, calcium signalling and translocation of transcriptional factors, implicated in the regulation of gene transcription in T-cells.
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Affiliation(s)
- Naim Akhtar Khan
- University of Burgundy, Department of Physiology, UPRES EA4183 Lipids and Cell Signalling, Faculty of Life Sciences, Dijon, France.
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The role of mast cell-derived secreted phospholipases A2 in respiratory allergy. Biochimie 2010; 92:588-93. [PMID: 20219624 DOI: 10.1016/j.biochi.2010.02.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 02/19/2010] [Indexed: 11/23/2022]
Abstract
Secreted phospholipases A(2) (sPLA(2)s) are molecules released in plasma and biological fluids of patients with systemic inflammatory, autoimmune and allergic diseases. These molecules exert proinflammatory effects by either enzymatic-mechanisms or through binding to surface molecules expressed on inflammatory cells. sPLA(2)s are released at low levels in the normal airways and tend to increase during respiratory allergies (e.g., rhinitis and bronchial asthma) as the result of local secretion. Several sPLA(2) isoforms are expressed in the human lung and some of them (e.g., group IIA and group X) are released in the airways of patients with rhinitis or asthma. Mast cells play a major role in the pathogenesis of respiratory allergies and other chronic inflammatory lung diseases. Recent evidence indicates that mast cells purified from human lung express most of the sPLA(2) isoforms so far described. IgE-mediated activation of these cells induce the release of sPLA(2)s suggesting that mast cells are a main source of extracellular sPLA(2)s during allergic reactions. Once released, sPLA(2)s may contribute to the generation of eicosanoids (e.g., PGD(2) and LTC(4)) and to the release of preformed mediators (e.g., histamine) by an autocrine loop involving the interaction of sPLA(2)s with surface molecules such as heparan sulphate proteoglycans or the M-type receptor. Thus, mast cell-derived sPLA(2)s may play an important role in the initiation and amplification of the inflammatory reactions in patients with allergic rhinitis and bronchial asthma.
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Kim W, Khan NA, McMurray DN, Prior IA, Wang N, Chapkin RS. Regulatory activity of polyunsaturated fatty acids in T-cell signaling. Prog Lipid Res 2010; 49:250-61. [PMID: 20176053 DOI: 10.1016/j.plipres.2010.01.002] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 01/06/2010] [Accepted: 01/19/2010] [Indexed: 12/25/2022]
Abstract
n-3 Polyunsaturated fatty acids (PUFA) are considered to be authentic immunosuppressors and appear to exert beneficial effects with respect to certain immune-mediated diseases. In addition to promoting T-helper 1 (Th1) cell to T-helper 2 (Th2) cell effector T-cell differentiation, n-3 PUFA may also exert anti-inflammatory actions by inducing apoptosis in Th1 cells. With respect to mechanisms of action, effects range from the modulation of membrane receptors to gene transcription via perturbation of a number of second messenger cascades. In this review, the putative targets of anti-inflammatory n-3 PUFA, activated during early and late events of T-cell activation will be discussed. Studies have demonstrated that these fatty acids alter plasma membrane micro-organization (lipid rafts) at the immunological synapse, the site where T-cells and antigen-presenting cells (APC) form a physical contact for antigen initiated T-cell signaling. In addition, the production of diacylglycerol and the activation of different isoforms of protein kinase C (PKC), mitogen-activated protein kinase (MAPK), calcium signaling, and nuclear translocation/activation of transcriptional factors, can be modulated by n-3 PUFA. Advantages and limitations of diverse methodologies to study the membrane lipid raft hypothesis, as well as apparent contradictions regarding the effect of n-3 PUFA on lipid rafts will be critically presented.
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Affiliation(s)
- Wooki Kim
- Program in Integrative Nutrition and Complex Diseases, Center for Environmental and Rural Health, Texas A&M University, USA
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Tang F, Chen Z, Ciszewski C, Setty M, Solus J, Tretiakova M, Ebert E, Han J, Lin A, Guandalini S, Groh V, Spies T, Green P, Jabri B. Cytosolic PLA2 is required for CTL-mediated immunopathology of celiac disease via NKG2D and IL-15. ACTA ACUST UNITED AC 2009; 206:707-19. [PMID: 19237603 PMCID: PMC2699120 DOI: 10.1084/jem.20071887] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
IL-15 and NKG2D promote autoimmunity and celiac disease by arming cytotoxic T lymphocytes (CTLs) to cause tissue destruction. However, the downstream signaling events underlying these functional properties remain unclear. Here, we identify cytosolic phospholipase A2 (cPLA2) as a central molecule in NKG2D-mediated cytolysis in CTLs. Furthermore, we report that NKG2D induces, upon recognition of MIC+ target cells, the release of arachidonic acid (AA) by CTLs to promote tissue inflammation in association with target killing. Interestingly, IL-15, which licenses NKG2D-mediated lymphokine killer activity in CTLs, cooperates with NKG2D to induce cPLA2 activation and AA release. Finally, cPLA2 activation in intraepithelial CTLs of celiac patients provides an in vivo pathophysiological dimension to cPLA2 activation in CTLs. These results reveal an unrecognized link between NKG2D and tissue inflammation, which may underlie the emerging role of NKG2D in various immunopathological conditions and define new therapeutic targets.
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Affiliation(s)
- Fangming Tang
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
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Involvement of epigenetic mechanisms in the regulation of secreted phospholipase A2 expressions in Jurkat leukemia cells. Neoplasia 2008; 10:1195-203. [PMID: 18953428 DOI: 10.1593/neo.08640] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 08/12/2008] [Accepted: 08/12/2008] [Indexed: 02/03/2023] Open
Abstract
Epigenetic changes provide a frequent mechanism for transcriptional silencing of genes in cancer cells. We previously established that epigenetic mechanisms are important for control of group IIA phospholipase A(2) (PLA2G2A) gene transcription in human DU-145 prostate cells. In this study, we analyzed the involvement of such mechanisms in the regulation of five sPLA(2) isozymes and the M-type receptor of sPLA(2) (sPLA(2)-R) in human leukemic Jurkat cells. These cells constitutively expressed sPLA(2)-IB, sPLA(2)-III, sPLA(2)-X, and sPLA(2)-R but not sPLA(2)-IIA and sPLA(2)-V. Transcription of sPLA(2)-IIA and sPLA(2)-V was, however, detected after exposure of cells to the DNA demethylating agent, 5-aza-2'-deoxycytidine (5-aza-dC). Expression of sPLA(2)-IIA was further enhanced by additional exposure to interferon-gamma and blocked by inhibitors of specificity protein 1, nuclear factor kappaB, and Janus kinase/signal transducer and activator of transcription-dependent pathways. Sequence analysis and methylation-specific polymerase chain reaction of bisulfite-modified genomic DNA revealed two 5'-CpG sites (-111 and -82) in the sPLA(2)-IIA proximal promoter that were demethylated after 5-aza-dC treatment. These sites may be involved in the DNA binding of specificity protein 1 and other transcription factors. Similar findings after treatment of human U937 leukemia cells with 5-aza-dC indicate that this mechanism of PLA2G2A gene silencing is not restricted to Jurkat and DU-145 cells. These data establish that regulation of sPLA(2)-IIA and sPLA(2)-V in Jurkat and other cells involves epigenetic silencing by DNA hypermethylation.
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Cinque B, Fanini D, Di Marzio L, Palumbo P, La Torre C, Donato V, Velardi E, Bruscoli S, Riccardi C, Cifone M. Involvement of cPLA2 Inhibition in Dexamethasone-Induced Thymocyte Apoptosis. Int J Immunopathol Pharmacol 2008; 21:539-51. [DOI: 10.1177/039463200802100307] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Various molecular mechanisms have been suggested to be involved in dexamethasone induced thymocyte apoptosis. In this study we show that pharmacological inhibition of cytoplasmic PLA2 in mouse thymocytes for 18 h with arachidonyl trifluoromethyl ketone (AACOCF3) (10 μM) and palmitoyl trifluoromethyl ketone (PACOCF3) (10 μM) induced a drastic increase of thymocyte apoptosis comparable to that observed following Dex (10−7 M) treatment, while inhibition of secretory PLA2 with p-bromophenacyl bromide (pBPB) (20 μM) did not. AACOCF3-induced thymocyte apoptosis, similarly to Dex-induced thymocyte apoptosis, was eliminated by cell pre-treatment with the PI-PLCβ inhibitor, U73122, but not by the PC-PLC inhibitor D609. These observations were corroborated by the ability of AACOCF3, like Dex, to induce a rapid and transient increase in DAG generation. In addition, AACOCF3-induced apoptosis involved the activation of the acidic sphingomyelinase (aSMase) but not of the neutral sphingomyelinase (nSMase), as evaluated by measurements of enzyme activity in cell extracts following thymocyte exposure to AACOCF3 and by the ability of monensin to inhibit AACOCF3-induced thymocyte apoptosis. In addition, the AACOCF3 apoptotic effect resulted in an early increase of ceramide levels. AACOCF3-induced thymocyte apoptosis involved the activation of caspase 3, and cell pre-treatment with a caspase 3 inhibitor prevented AACOCF3-induced apoptosis. These observations suggest that cPLA2 inhibition may have a role in Dex-induced thymocyte apoptosis and highlight the importance of cPLA2 activity in thymocyte survival.
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Affiliation(s)
| | | | - L. Di Marzio
- Department of Drug Science, University G. d'Annunzio, Chieti
| | | | | | - V. Donato
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Perugia, Perugia, Italy
| | - E. Velardi
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Perugia, Perugia, Italy
| | - S. Bruscoli
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Perugia, Perugia, Italy
| | - C. Riccardi
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Perugia, Perugia, Italy
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Differential expression of secretory phospholipases A2 in normal and malignant prostate cell lines: regulation by cytokines, cell signaling pathways, and epigenetic mechanisms. Neoplasia 2008; 10:279-86. [PMID: 18320072 DOI: 10.1593/neo.07965] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 01/07/2008] [Accepted: 01/10/2008] [Indexed: 12/31/2022]
Abstract
Upregulation of group IIA phospholipase A(2) (sPLA(2)-IIA) correlates with prostate tumor progression suggesting prooncogenic properties of this protein. Here, we report data on expression of three different sPLA(2) isozymes (groups IIA, V, and X) in normal (PrEC) and malignant (DU-145, PC-3, and LNCaP) human prostate cell lines. All studied cell lines constitutively expressed sPLA(2)-X, whereas sPLA(2)-V transcripts were identified only in malignant cells. In contrast, no expression of sPLA(2)-IIA was found in PrEC and DU-145 cells, but it was constitutively expressed by IFN-gamma in LNCaP and PC-3 cells. Expression of sPLA(2)-IIA is upregulated in PC-3 and in PrEC cell in a signal transducer and activator of transcription-1-dependent manner, but not in LNCaP cell. Additional signaling pathways regulating sPLA(2)-IIA expression include cAMP/protein kinase A, p38 mitogen-activated protein kinase, protein kinase C, Rho-kinase, and mitogen-activated/extracellular response protein kinase / extracellular signal-regulated kinase. No deletions were revealed in the sPLA(2)-IIA gene from DU-145 cells lacking the expression of sPLA(2)-IIA. Reexpression of sPLA(2)-IIA was induced by 5-aza-2'-deoxycytidine demonstrating that DNA methylation is implicated in the regulation of sPLA(2)-II. Together, these data suggest that sPLA(2)-IIA and sPLA(2)-V, but not sPLA(2)-X, are differentially expressed in normal and malignant prostate cells under the control of proinflammatory cytokines; epigenetic mechanisms appear involved in the regulation of sPLA(2)-IIA expression, at least in DU-145 cells.
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10
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Humphries JE, Yoshino TP. Regulation of hydrogen peroxide release in circulating hemocytes of the planorbid snail Biomphalaria glabrata. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2008; 32:554-62. [PMID: 17981329 PMCID: PMC2271030 DOI: 10.1016/j.dci.2007.09.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 08/31/2007] [Accepted: 09/16/2007] [Indexed: 05/18/2023]
Abstract
Biomphalaria spp. serve as obligate intermediate hosts for the human blood fluke Schistosoma mansoni. Following S. mansoni penetration of Biomphalaria glabrata, hemocytes of resistant snails migrate towards the parasite, encasing the larva in a multicellular capsule resulting in its destruction via a cytotoxic reaction. Recent studies have revealed the importance of hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) in parasite killing [Hahn UK, Bender RC, Bayne CJ. Killing of Schistosoma mansoni sporocysts by hemocytes from resistant Biomphalaria glabrata: role of reactive oxygen species. J Parasitol 2001;87:292-9; Hahn UK, Bender RC, Bayne CJ. Involvement of nitric oxide in killing of Schistosoma mansoni sporocysts by hemocytes from resistant Biomphalaria glabrata. J Parasitol 2001;87:778-85]. It is assumed that H(2)O(2) and NO production is tightly regulated although the specific molecules involved remain largely unknown. Consequently, the potential role of cell signaling pathways in B. glabrata hemocyte H(2)O(2) production was investigated by evaluating the effects of specific inhibitors of selected signaling proteins. Results suggest that both ERK and p38 MAPKs are involved in the regulation of B. glabrata H(2)O(2) release in response to stimulation by PMA and galactose-conjugated BSA. However, the involvement of the signaling proteins PKC, PI(3) kinase and PLA(2) differs between PMA- and BSA-gal-induced H(2)O(2) production.
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Affiliation(s)
- Judith E Humphries
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
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Triggiani M, Granata F, Frattini A, Marone G. Activation of human inflammatory cells by secreted phospholipases A2. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1289-300. [PMID: 16952481 DOI: 10.1016/j.bbalip.2006.07.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 07/07/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
Secreted phospholipases A(2) (sPLA(2)s) are enzymes detected in serum and biological fluids of patients with various inflammatory, autoimmune and allergic disorders. Different isoforms of sPLA(2)s are expressed and released by human inflammatory cells, such as neutrophils, eosinophils, T cells, monocytes, macrophages and mast cells. sPLA(2)s generate arachidonic acid and lysophospholipids thus contributing to the production of bioactive lipid mediators in inflammatory cells. However, sPLA(2)s also activate human inflammatory cells by mechanisms unrelated to their enzymatic activity. Several human and non-human sPLA(2)s induce degranulation of mast cells, neutrophils and eosinophils and activate exocytosis in macrophages. In addition some, but not all, sPLA(2) isoforms promote cytokine and chemokine production from macrophages, neutrophils, eosinophils, monocytes and endothelial cells. These effects are primarily mediated by binding of sPLA(2)s to specific membrane targets (heparan sulfate proteoglycans, M-type, N-type or mannose receptors) expressed on effector cells. Thus, sPLA(2)s may play an important role in the initiation and amplification of inflammatory reactions by at least two mechanisms: production of lipid mediators and direct activation of inflammatory cells. Selective inhibitors of sPLA(2)-enzymatic activity and specific antagonists of sPLA(2) receptors are current being tested for pharmacological treatment of inflammatory and autoimmune diseases.
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Affiliation(s)
- Massimo Triggiani
- Division of Clinical Immunology and Allergy, Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, 80131 Naples, Via Pansini 5, Italy.
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Jenkins CM, Yan W, Mancuso DJ, Gross RW. Highly selective hydrolysis of fatty acyl-CoAs by calcium-independent phospholipase A2beta. Enzyme autoacylation and acyl-CoA-mediated reversal of calmodulin inhibition of phospholipase A2 activity. J Biol Chem 2006; 281:15615-24. [PMID: 16595686 DOI: 10.1074/jbc.m511623200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calcium-independent phospholipase A2beta (iPLA2beta) participates in numerous diverse cellular processes, such as arachidonic acid release, insulin secretion, calcium signaling, and apoptosis. Herein, we demonstrate the highly selective iPLA2beta-catalyzed hydrolysis of saturated long-chain fatty acyl-CoAs (palmitoyl-CoA approximately myristoyl-CoA >> stearoyl-CoA >> oleoyl-CoA approximately = arachidonoyl-CoA) present either as monomers in solution or guests in host membrane bilayers. Site-directed mutagenesis of the iPLA2beta catalytic serine (S465A) completely abolished acyl-CoA thioesterase activity, demonstrating that Ser-465 catalyzes both phospholipid and acyl-CoA hydrolysis. Remarkably, incubation of iPLA2beta with oleoyl-CoA, but not other long-chain acyl-CoAs, resulted in robust stoichiometric covalent acylation of the enzyme. Moreover, S465A mutagenesis or pretreatment of wild-type iPLA2beta with (E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one unexpectedly increased acylation of the enzyme, indicating the presence of a second reactive nucleophilic residue that participates in the formation of the fatty acyl-iPLA2beta adduct. Radiolabeling of intact Sf9 cells expressing iPLA2beta with [3H]oleic acid demonstrated oleoylation of the membrane-associated enzyme. Partial trypsinolysis of oleoylated iPLA2beta and matrix-assisted laser desorption ionization mass spectrometry analysis localized the acylation site to a hydrophobic 25-kDa fragment (residues approximately 400-600) spanning the active site to the calmodulin binding domain. Intriguingly, calmodulin-Ca2+ blocked acylation of iPLA2beta by oleoyl-CoA. Remarkably, the addition of low micromolar concentrations (5 microM) of oleoyl-CoA resulted in reversal of calmodulin-mediated inhibition of iPLA2 beta phospholipase A2 activity. These results collectively identify the molecular species-specific acyl-CoA thioesterase activity of iPLA2beta, demonstrate the presence of a second active site that mediates iPLA2beta autoacylation, and identify long-chain acyl-CoAs as potential candidates mediating calcium influx factor activity.
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Affiliation(s)
- Christopher M Jenkins
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Joshi B, Khedouci S, Dagur PK, Hichami A, Sengupta U, Khan NA. On Cell Signalling Mechanism of Mycobaterium Leprae Soluble Antigen (MLSA) in Jurkat T Cells. Mol Cell Biochem 2006; 287:157-64. [PMID: 16583135 DOI: 10.1007/s11010-006-9132-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 01/10/2006] [Indexed: 11/28/2022]
Abstract
We investigated the role of Mycobaterium leprae soluble antigen (MLSA) in the modulation of calcium signalling, phosphorylation of mitogen-activated protein (MAP) kinases and IL-2 mRNA expression in human Jurkat T cells. We observed that MLSA induced an increase in free intracellular calcium concentrations, [Ca2+]i, via opening CRAC (Ca2+-release activated- Ca2+) channels. Furthermore, MLSA failed to potentiate both thapsigargin- and anti-CD3 antibodies-induced capacitative calcium influx in Jurkat T cells. We observed that MLSA failed to affect the degree of phosphorylation of two MAP kinases, i.e., ERK1/ERK2, stimulated by anti-CD3 antibodies alone or phorbol 12-myristate 13-acetate (PMA) alone. In order to mimic co-stimulation of T cells, we stimulated them by both PMA and anti-CD3 antibodies. MLSA significantly curtailed the phosphorylation of ERK1/ERK2, stimulated by both PMA and anti-CD3 antibodies in Jurkat T cells. Also MLSA was found to reduce the transcription of IL-2 gene in PMA plus anti-CD3 antibodies-activated Jurkat T cells. Our finding demonstrates that Ca2+ influx via CRAC channels, inhibition of ERK1/ERK2 phosphorylation and IL-2 gene transcription may be implicated in immunosuppressive effects of MLSA antigen.
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Affiliation(s)
- Beenu Joshi
- Central JALMA Institute for Leprosy and other Mycobacterial Diseases (ICMR), Taj Ganj, Agra, U.P, 282001, India
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Diaz O, Mébarek-Azzam S, Benzaria A, Dubois M, Lagarde M, Némoz G, Prigent AF. Disruption of Lipid Rafts Stimulates Phospholipase D Activity in Human Lymphocytes: Implication in the Regulation of Immune Function. THE JOURNAL OF IMMUNOLOGY 2005; 175:8077-86. [PMID: 16339545 DOI: 10.4049/jimmunol.175.12.8077] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent evidence suggests that phospholipase D (PLD) can be regulated through its association/dissociation to lipid rafts. We show here that modifying lipid rafts either by cholesterol depletion using methyl-beta-cyclodextrin and filipin or by conversion of sphingomyelin to ceramide with exogenous bacterial sphingomyelinase (bSMase) markedly activated the PLD of human PBMC. bSMase was the most potent PLD activator, giving maximal 6- to 7-fold increase in PLD activity. Triton X-100-treated lysates prepared from control PBMC and from bSMase-treated cells were fractionated by centrifugation on sucrose density gradient. We observed that bSMase treatment of the cells induced a larger ceramide increase in raft than in nonraft membranes and displaced both the Src kinase Lck and PLD1 out of the raft fractions. In addition, the three raft-modifying agents markedly inhibited the lymphoproliferative response to mitogenic lectin. To examine further the potential role of PLD activation in the control of lymphocyte responses, we transiently overexpressed either of the PLD1 and PLD2 isoforms in Jurkat cells and analyzed the phorbol ester plus ionomycin-induced expression of IL-2 mRNA, which is one of the early responses of lymphocyte to activation. We observed a 43% decrease of IL-2 mRNA level in Jurkat cells overexpressing PLD1 as compared with mock- or PLD2-transfected cells, which indicates that elevated PLD1, but not PLD2, activity impairs lymphocyte activation. Altogether, the present results support the hypothesis that PLD1 is activated by exclusion from lipid rafts and that this activation conveys antiproliferative signals in lymphoid cells.
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Affiliation(s)
- Olivier Diaz
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche (UMR) 585/Institut National des Sciences Appliquées-LYON, Physiopathologie des Lipides et Membranes, Villeurbanne, France
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15
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Triggiani M, Granata F, Giannattasio G, Marone G. Secretory phospholipases A2 in inflammatory and allergic diseases: not just enzymes. J Allergy Clin Immunol 2005; 116:1000-6. [PMID: 16275367 DOI: 10.1016/j.jaci.2005.08.011] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 08/04/2005] [Accepted: 08/08/2005] [Indexed: 12/30/2022]
Abstract
Secretory phospholipases A(2) (sPLA(2)s) are molecules released in plasma and biologic fluids of patients with systemic inflammatory, autoimmune, and allergic diseases. Several sPLA(2) isoforms are expressed and released by such human inflammatory cells as neutrophils, eosinophils, basophils, T cells, monocytes, macrophages, and mast cells. Certain sPLA(2)s release arachidonic acid, thereby providing the substrate for the biosynthesis of proinflammatory eicosanoids. However, there are other mechanisms by which sPLA(2)s might participate in the synthesis of lipid mediators. Interestingly, sPLA(2)s activate inflammatory cells through mechanisms unrelated to their enzymatic activity. Several sPLA(2)s induce degranulation of mast cells and eosinophils and activate exocytosis in macrophages. Furthermore, sPLA(2)s promote cytokine and chemokine production from macrophages, neutrophils, eosinophils, monocytes, and endothelial cells. Some of these effects are mediated by the binding of sPLA(2)s to specific receptors expressed on effector cells. Thus sPLA(2)s might play important roles in the initiation and amplification of the inflammatory reaction. Selective inhibitors of sPLA(2)s and specific antagonists of sPLA(2) receptors might prove useful in the treatment of allergic and autoimmune diseases, such as bronchial asthma and rheumatoid arthritis.
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Affiliation(s)
- Massimo Triggiani
- Division of Clinical Immunology and Allergy, Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, Naples, Italy
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Chen YJ. Phospholipase A(2) activity of beta-bungarotoxin is essential for induction of cytotoxicity on cerebellar granule neurons. ACTA ACUST UNITED AC 2005; 64:213-23. [PMID: 15849737 DOI: 10.1002/neu.20137] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The aim of this study was to investigate the mechanism of the cytotoxic effect of beta-bungarotoxin (beta-BuTX), a presynaptic neurotoxin, on rat cerebellar granule neurons (CGNs). The maturation of CGNs is characterized by the prominent dense neurite networks that became fragmented after treatment with beta-BuTX, and this cytotoxic effect of beta-BuTX on CGNs was in a dose- and time-dependant manner. The cytotoxic effect of beta-BuTX was found to be more potent than other toxins, such as alpha-BuTX, cardiotoxin, melittin, and Naja naja atra venom phospholipase A(2). Meanwhile, undifferentiated neuroblastoma neuronal cell lines, IMR-32 and SK-N-MC, and astrocytes were found to be resistant to beta-BuTX. These results indicated that only the mature CGNs were sensitive to beta-BuTX insults. None of the following chemicals: antioxidants, K(+)-channel activator, K(+)-channel antagonists, intracellular Ca(2+) chelator, Ca(2+)-channel blockers, NMDA receptor antagonists, and nitric oxide synthase inhibitor tested, were able to reduce beta-BuTX-induced cytotoxicity. However, secretory type phospholipase A(2) inhibitors (glycyrrhizin and aristolochic acid) and a free radical scavenger (5,5-dimethyl pyrroline N-oxide, DMPO) could attenuate not only beta-BuTX-induced cytotoxicity but also ROS production and caspase-3 activation. These data suggest that phospholipase A(2) activity of beta-BuTX may be responsible for free radical generation and caspase-3 activation that accounts for the observed cytotoxic effect. It is proposed that the CGNs can be a useful tool for studying interactions of the molecules on neuronal plasma membrane with beta-BuTX that mediates the specific cytotoxicity.
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Affiliation(s)
- Yu-Jen Chen
- Department of Medical Technology and Institute of Biotechnology, Yuanpei University of Science and Technology, Hsinchu, Taiwan.
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Denys A, Hichami A, Khan NA. n-3 PUFAs modulate T-cell activation via protein kinase C-α and -ε and the NF-κB signaling pathway. J Lipid Res 2005; 46:752-8. [PMID: 15627650 DOI: 10.1194/jlr.m400444-jlr200] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We elucidated the mechanisms of action of two n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in Jurkat T-cells. Both DHA and EPA were principally incorporated into phospholipids in the following order: phosphatidylcholine < phosphatidylethanolamine < phosphatidylinositol/phosphatidylserine. Furthermore, two isoforms of phospholipase A(2) (i.e., calcium-dependent and calcium-independent) were implicated in the release of DHA and EPA, respectively, during activation of these cells. The two fatty acids inhibited the phorbol 12-myristate 13-acetate (PMA)-induced plasma membrane translocation of protein kinase C (PKC)-alpha and -epsilon. The two n-3 PUFAs also inhibited the nuclear translocation of nuclear factor kappaB (NF-kappaB) and the transcription of the interleukin-2 (IL-2) gene in PMA-activated Jurkat T-cells. Together, these results demonstrate that DHA and EPA, being released by two isoforms of phospholipase A(2), modulate IL-2 gene expression by exerting their action on two PKC isoforms and NF-kappaB in Jurkat T-cells.
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Affiliation(s)
- Anne Denys
- University of Burgundy, Department of Physiology, Unité Propre de Recherche et de l'Enseignement Supérieur (UPRES) Lipids and Nutrition, Faculty of Life Sciences, Dijon 21000, France
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Aires V, Adote S, Hichami A, Moutairou K, Boustani ESE, Khan NA. Modulation of intracellular calcium concentrations and T cell activation by prickly pear polyphenols. Mol Cell Biochem 2004; 260:103-10. [PMID: 15228091 DOI: 10.1023/b:mcbi.0000026061.57326.28] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Opuntia ficus indica (prickly pear) polyphenolic compounds (OFPC) triggered an increase in [Ca2+]i in human Jurkat T-cell lines. Furthermore, OFPC-induced rise in [Ca2+]i was significantly curtailed in calcium-free buffer (0% Ca2+) as compared to that in 100% Ca2+ medium. Preincubation of cells with tyrphostin A9, an inhibitor of Ca2+ release-activated Ca2+ (CRAC) channels, significantly diminished the OFPC-induced sustained response on the increases in [Ca2+]i. Lanthanum and nifedipine, the respective inhibitors of voltage-dependent and L-type calcium channels, failed to curtail significantly the OFPC-induced calcium response. As OFPC still stimulated increases in [Ca2+]i in 0% Ca2+ medium, the role of intracellular calcium was investigated. Hence, addition of thapsigargin (TG), an inhibitor of Ca2+-ATPase of the endoplasmic reticulum (ER), during the OFPC-induced peak response exerted an additive effect, indicating that the mechanism of action of these two agents are different. Furthermore, U73122, an inhibitor of IP3 production, completely abolished increases in [Ca2+]i, induced by OFPC, suggesting that these polyphenols induce the production of IP3 that recruits calcium from ER pool. Polyphenolic compounds do act extracellularly as addition of fatty acid-free bovine serum albumin (BSA) significantly diminished the rise in [Ca2+]i evoked by the formers. OFPC also induced plasma membrane hyperpolarisation which was reversed by addition of BSA. OFPC were found to curtail the expression of IL-2 mRNA and T-cell blastogenesis. Together these results suggest that OFPC induce increases in [Ca2+]i via ER pool and opening of CRAC channels, and exert immunosuppressive effects in Jurkat T-cells.
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Affiliation(s)
- Virginie Aires
- UPRES Lipides and Nutrition, Université de Bourgogne, Faculté des Sciences de la vie 6, Dijon, France
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Ito M, Ishikawa Y, Kiguchi H, Komiyama K, Murakami M, Kudo I, Akasaka Y, Ishii T. Distribution of type V secretory phospholipase A2 expression in human hepatocytes damaged by liver disease. J Gastroenterol Hepatol 2004; 19:1140-9. [PMID: 15377291 DOI: 10.1111/j.1440-1746.2004.03435.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND AND AIM Type V secretory phospholipase A2 (sPLA2-V) is a key enzyme in the arachidonate cascade. However, the distribution of sPLA2-V in human liver has not yet been investigated. In this study, the significance of sPLA2-V expression in human hepatocytes damaged by liver disease was investigated. METHODS Samples of liver tissue from patients with chronic hepatitis B and C, hepatitis virus-related liver cirrhosis, and congestive hepatocyte injury were immunostained with antibodies against sPLA2-V, cyclooxygenase (COX)-2, hepatitis viral antigens, transforming growth factor (TGF)-beta1, interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. RESULTS In chronic hepatitis patients, sPLA2-V-positive hepatocytes were scattered in the liver lobules, while cyclooxygenase-2, IL-1beta, and TNF-alpha were diffusely expressed. Hepatocytes around necroinflammatory lesions were strongly positive for sPLA2-V. Some sPLA2-V-positive hepatocytes were also positive for viral antigens. TGF-beta1 was expressed only in fibrotic lesions. The pattern of distribution of these proteins in liver cirrhosis patients was similar to that in chronic hepatitis patients, but sPLA2-V expression tended to be more intense than in chronic hepatitis. In the congestive liver, sPLA2-V, COX-2, and the two cytokines were diffusely expressed in surviving hepatocytes. CONCLUSIONS sPLA2-V expression in hepatocytes is induced by viral infection, fibrosis, and circulatory disturbance. Immunostaining using sPLA2-V antibody is useful for the detection of injured hepatocytes in patients with liver diseases.
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Affiliation(s)
- Masamichi Ito
- Department of Pathology, Toho University School of Medicine, Tokyo, Japan.
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Ryu SB. Phospholipid-derived signaling mediated by phospholipase A in plants. TRENDS IN PLANT SCIENCE 2004; 9:229-235. [PMID: 15130548 DOI: 10.1016/j.tplants.2004.03.004] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Affiliation(s)
- Stephen B Ryu
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea.
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Hichami A, Joshi B, Simonin AM, Khan NA. Role of three isoforms of phospholipase A2 in capacitative calcium influx in human T-cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:5557-63. [PMID: 12423354 DOI: 10.1046/j.1432-1033.2002.03261.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study was conducted on human Jurkat T-cell lines in order to elucidate the role of phospholipase A2 in capacitative calcium entry. We have employed thapsigargin (TG) that induces increases in [Ca2+]i by emptying the calcium pool of endoplasmic reticulum, followed by capacitative calcium entry. We designed a Ca2+ free/Ca2+ reintroduction (CFCR) protocol for the experiments, conducted in Ca2+-free medium. By employing CFCR protocol, we observed that addition of exogenous arachidonic acid (AA) stimulated TG-induced capacitative calcium influx. The liberation of endogenous AA and its autocrine action seems to be implicated during TG-induced capacitative calcium influx: TG potentiates the induction of constitutively expressed mRNA of four PLA2 isoforms (type 1B, IV, V, VI), the inhibitors of the three PLA2 isotypes (type 1B, V, VI) inhibit TG-induced release of [3H]AA into the extracellular medium, and finally, these PLA2 inhibitors do curtail TG-stimulated capacitative calcium entry in these cells. These results suggest that stimulation of three isoforms of PLA2 by thapsigargin liberates free AA that, in turn, induces capacitative calcium influx in human T-cells.
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Affiliation(s)
- Aziz Hichami
- UPRES Lipides & Nutrition, Université de Bourgogne 21000 Dijon, France; Central Jalma Research Institute for Leprosy, Agra, UP, India
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